Estimate of traffic from Spain and the UK (source:
\r\n\tThis book will intend to provide the reader all the necessary information on apheresis with a comprehensive overview including techniques for therapeutic apheresis, indications of apheresis in the light of guidelines, adverse events associated with apheresis, as well as the care of the apheresis patient.
The ACC/AHA Task Force on Practice Guidelines herein revises and updates the original “Guidelines for Coronary Angiography,” published in 1987 The frequent and still-growing use of coronary angiography, its relatively high costs, its inherent risks and the ongoing evolution of its indications have given this revision urgency and priority.
The expert committee appointed included private practitioners and academicians. Committee members were selected to represent both experts in coronary angiography and senior clinician consultants. Representatives from the family practice and internal medicine professions were also included on the committee .
Coronary angiography is defined as the radiographic visualization of the coronary vessels after the injection of radiopaque contrast media. The radiographic images are permanently recorded for future review with either 35 mm cine film or digital recording. Percutaneous or cutdown techniques, usually from the femoral or brachial artery, are used for insertion of special intravascular catheters. Coronary angiography further requires selective cannulation of the ostium of the left and right coronary arteries and, if present, each saphenous vein graft or internal mammary artery graft to obtain optimal selective contrast injection and imaging. Numerous specialized catheters have been designed for this purpose. Physicians performing these procedures must be technically proficient in all aspects of the procedure and have a complete understanding of the clinical indications and risks of the procedure and of coronary anatomy, physiology and pathology. It is also important that these physicians understand the fundamentals of optimal radiographic imaging and radiation safety. Coronary angiography is usually performed as part of cardiac catheterization, which may also involve angiography of other vessels or cardiac chambers, and hemodynamic assessment as needed for a complete invasive diagnostic evaluation of the individual patient’s cardiovascular condition[2,3].
The purpose of coronary angiography is to define coronary anatomy and the degree of luminal obstruction of the coronary arteries. Information obtained from the procedure includes identification of the location, length, diameter, and contour of the coronary arteries; the presence and severity of coronary luminal obstruction(s); characterization of the nature of the obstruction (including the presence of atheroma, thrombus, dissection, spasm, or myocardial bridging), and an assessment of blood flow. In addition, the presence and extent of coronary collateral vessels can be assessed.
Coronary angiography remains the standard for assessment of anatomic coronary disease, because no other currently available test can accurately define the extent of coronary luminal obstruction. Because the technique can only provide information about abnormalities that narrow the lumen, it is limited in its ability to accurately define the etiology of the obstruction or detect the presence of nonobstructive atherosclerotic disease.A coronary angiography, which can help diagnose heart conditions, is the most common type of heart catheter procedure. [2,3]
Coronary atherosclerosis is a slowly progressive process that can be clinically inapparent for long periods of time [78–80]. Coronary disease often becomes clinically evident because of the occurrence of symptoms, such as angina or those associated with MI. Patients with known CAD are those in whom the disease has been documented by either angiography or MI. “Suspected coronary disease” means that a patient’s symptoms or other clinical characteristics suggest a high likelihood for significant CAD and its related adverse outcomes but that evidence of CAD has not yet been documented as defined above.
Patients may develop symptoms at one point in time but may become asymptomatic thereafter as the result of a change in the disease or as the result of therapy. For instance, many patients are symptomatic after an uncomplicated MI, as are patients with mild angina, who can be rendered asymptomatic by medications. The severity of clinical presentations and the degree of provocable ischemia on noninvasive testing are the principal factors used in determining the appropriateness of coronary angiography.
Patients with CAD may become symptomatic in many different ways but most commonly develop angina pectoris. In this document, angina pectoris (or simply angina) means a chest discomfort due to myocardial ischemia, often described as a transient squeezing, pressure-like precordial discomfort. Angina is generally provoked by physical effort (particularly during the postprandial state), with exposure to cold environment or by emotional stress. The discomfort on effort is relieved by rest, its duration being a matter of minutes. The ease of provocation, frequency and duration of episodes may remain relatively unchanged in individuals for extended time periods, leading to the term “stable angina pectoris.”
Recommendations for Coronary Angiography in Patients With Nonspecific Chest Pain Class I
High-risk findings on noninvasive testing. (Level of Evidence: B)
Class IIa: None.
Patients with recurrent hospitalizations for chest pain who have abnormal (but not high-risk) or equivocal findings on noninvasive testing. (Level of Evidence: B)
All other patients with nonspecific chest pain. (Level of Evidence: C)
The acute coronary syndromes include unstable angina, non–Q-wave MI, and acute Q-wave MI. The diagnosis of unstable angina has been complicated by a broad range of presentations that can vary between atypical chest pain and acute MI. An expert panel of clinicians attempted to clarify the definition of unstable angina in the recently published “Clinical Practice Guideline for Unstable Angina”[129,130]. Three possible presentations are described:
Symptoms of angina at rest (usually prolonged 20 minutes);
New-onset (<2 months) exertional angina of at least CCS class III in severity;
Variant angina, non–Q-wave MI and recurrent angina24 hours after MI are considered part of the spectrum of unstable angina. However, in this document, non–Q-wave MI is discussed in the section on acute MI. [4,5]
Recommendations for Coronary Angiography in Patients With Postrevascularization Ischemia
Suspected abrupt closure or subacute stent thrombosis after percutaneous revascularization. (Level of Evidence: B)
Recurrent angina or high-risk criteria on noninvasive evaluation (Table 5) within nine months of percutaneous revascularization. (Level of Evidence: C)
Recurrent symptomatic ischemia within 12 months of CABG. (Level of Evidence: B)
Noninvasive evidence of high-risk criteria occurring at any time postoperatively. (Level of Evidence:B)
Recurrent angina inadequately controlled by medical means after revascularization. (Level of Evidence: C)
Asymptomatic post-PTCA patient suspected of having restenosis within the first months after angioplasty because of an abnormal noninvasive test but without noninvasive high-risk criteria. (Level of Evidence: B)
Recurrent angina without high-risk criteria on noninvasive testing occurring >1 year postoperatively. (Level of Evidence: C)
Asymptomatic postbypass patient in whom a deterioration in serial noninvasive testing has been documented but who is not high risk on noninvasive testing. (Level of Evidence: C)
Symptoms in a postbypass patient who is not a candidate for repeat revascularization. (Level of Evidence: C)
Routine angiography in asymptomatic patients after PTCA or other surgery, unless as part of an approved research protocol. (Level of Evidence: C)
Coronary angiography during the initial management of patients in the emergency department
Patients Presenting With Suspected MI and ST- segment Elevation or Bundle-Branch Block Of all patients who ultimately are diagnosed with acute MI, those resenting with ST-segment elevation have been studied most extensively. Patients with ST-segment elevation have a high likelihood of thrombus occluding the infarct-related artery [6,7]. Considerable data exist showing that coronary reperfusion can be accomplished either by intravenous thrombolytic therapy or direct mechanical intervention within the infarct-related artery. Because the benefit obtained is directly linked to the time required to reestablish normal distal blood flow [8–10], rapid triage decisions are mandatory, and delays in instituting reperfusion therapy must be minimized. The “ACC/AHA Guidelines for the Management of Patients with Acute Myocardial Infarction” provide a comprehensive discussion of the indications, contraindications, advantages, and disadvantages of thrombolytic therapy and direct coronary angioplasty . Although it is not the purpose of these guidelines to re-examine in detail the merits of these two reperfusion strategies, this is a rapidly evolving area, and some new information exists.
Recommendations for coronary angiography during the initial management of acute MI (MI suspected and ST-segment elevation or bundle-branch block present)
Coronary angiography coupled with the intent to perform primary PTCA
As an alternative to thrombolytic therapy in patients who can undergo angioplasty of the infarct artery within 12 hours of the onset of symptoms or beyond 12 hours if ischemic symptoms persist.
In patients who are within 36 hours of an acute ST elevation/Q-wave or new LBBB MI who develop cardiogenic shock, are less than 75 years of age and revascularization can be performed within 18 hours of the onset of shock
As a reperfusion strategy in patients who are candidates for reperfusion but who have a contraindication to fibrinolytic therapy, if angioplasty can be performed as outlined above in class I. (Level of Evidence: C)
In patients who are beyond 12 hours from onset of symptoms and who have no evidence of myocardial ischemia. (Level of Evidence: A)
In patients who are eligible for thrombolytic therapy and are undergoing primary angioplasty by an unskilled operator in a laboratory that does not have surgical capability. (Level of Evidence: B)
Recommendations for early coronary angiography in the patient with suspected MI (ST-segment elevation or BBB present) who has not undergone primary PTCA
Class I: None.
Class IIa: Cardiogenic shock or persistent hemodynamic instability.(Level of Evidence: B)
Evolving large or anterior infarction after Thrombolytic treatment when it is believed that reperfusion has not occurred and rescue PTCA is planned. (Level of Evidence: B)
Marginal hemodynamic status but not actual cardiogenic shock.(Level of Evidence: C)
In patients who have received thrombolytic therapy and have no symptoms of ischemia. (Level of Evidence:A)
Routine use of angiography and subsequent PTCA within 24 hours of administration of thrombolytic agents. (Level of Evidence: A)
Recommendations for early coronary angiography in acute MI (MI suspected but no st-segment elevation)
Persistent or recurrent (stuttering) episodes of symptomatic ischemia, spontaneous or induced, with or without associated ECG changes. (Level of Evidence:A)
The presence of shock, severe pulmonary congestion,or continuing hypotension. (Level of Evidence: B)
Class II: None.
Class III: None.
Hospital-management phase of acute MI
The hospital-management phase of acute MI can encompass several clinical situations. Some patients with acute MI present too late in their course to be candidates for reperfusion therapy, and in others, the occurrence of infarction may not be appreciated at he time of presentation. These groups skip the acute-treatment phase of MI and enter the hospital-management phase directly. During the hospital management phase, the actions of the clinician are driven by the consequences of the infarction, such as congestive heart failure, hemodynamic instability, recurrent ischemia or arrhythmias. Although it is still convenient to divide patients into those with Q-wave and non–Q-wave infarctions, some indications for coronary angiography are common to all patients with MI regardless of how they have been treated initially and whether or not Q waves ultimately develop.
Recommendations for use of coronary angiography in patients with valvular heart disease Class I
Before valve surgery or balloon valvotomy in an adult with chest discomfort, ischemia by noninvasive imaging, or both. (Level of Evidence: B)
Before valve surgery in an adult free of chest pain but with multiple risk factors for coronary disease. (Level of Evidence: C)
Infective endocarditis with evidence of coronary embolization. (Level of Evidence: C)
During left-heart catheterization performed for hemodynamic evaluation before aortic or mitral valve surgery in patients without preexisting evidence of coronary disease, multiple CAD risk factors or advanced age. (Level of Evidence: C)
Before cardiac surgery for infective endocarditis when there are no risk factors for coronary disease and no evidence of coronary embolization. (Level of Evidence: C)
In asymptomatic patients when cardiac surgery is not being considered. (Level of Evidence: C)
Before cardiac surgery when preoperative hemodynamic assessment by catheterization is unnecessary, and there is neither preexisting evidence for coronary disease, nor risk factors for CAD. (Level of Evidence: C)
Congenital heart disease
Although there are no large trials to support its use, coronary angiography is performed in congenital heart disease for two broad categorical indications. The first indication is to assess the hemodynamic impact of congenital coronary lesions (375). The second is to assess the presence of coronary anomalies, which by themselves may be innocent but whose presence, if unrecognized, may lead to coronary injury during the correction of other congenital heart lesions. Congenital anomalies with hemodynamic significance include congenital coronary artery stenosis or atresia, coronary artery fistula , anomalous left coronary artery arising from the pulmonary artery , and anomalous left coronary artery arising from the right coronary artery or right sinus of Valsalva and passing between the aorta and right ventricular outflow tract . Patients with congenital coronary stenosis may present with angina or unexplained sudden death in childhood, whereas patients whose left coronary passes between the pulmonary artery and aorta often have the same symptoms later in life. Patients with a coronary arteriovenous fistula often present with a continuous murmur or may have unexplained angina or congestive heart failure. Anomalous origin of the left coronary artery from the pulmonary artery should be suspected when there is unexplained MI or heart failure in early childhood. Other coronary anomalies of position or origin may cause no physiologic abnormality by themselves. Some, such as origin of the circumflex artery from the right sinus of Valsalva, are not associated with other congenital anomalies and present only as incidental findings and are significant only because they complicate the performance and interpretation of coronary angiograms.
Recommendations for use of coronary angiography in patients with congenital heart disease
Before surgical correction of congenital heart disease when chest discomfort or noninvasive evidence is suggestive of associated CAD. (Level of Evidence: C)
Before surgical correction of suspected congenital coronary anomalies such as congenital coronary artery stenosis, coronary arteriovenous fistula and anomalous origin of left coronary artery. (Level of Evidence: C)
Forms of congenital heart disease frequently associated with coronary artery anomalies that may complicate surgical management. (Level of Evidence: C)
Unexplained cardiac arrest in a young patient. (Level of Evidence: B)
Before corrective open heart surgery for congenital heart disease in an adult whose risk profile increases the likelihood of coexisting coronary disease. (Level of Evidence: C)
During left-heart catheterization for hemodynamic assessment of congenital heart disease in an adult in whom the risk of coronary disease is not high. (Level of Evidence: C)
In the routine evaluation of congenital heart disease in asymptomatic patients for whom heart surgery is not planned. (Level of Evidence: C)
Congestive heart failure
1. Systolic dysfunction
Although it was once believed that myocardial ischemia was either short-lived and resulted in little or no muscle dysfunction or resulted in infarction with permanent damage, it is now clear that a middle state may exist in which chronic ischemic nonfunctioning myocardium is present, to which function may return after myocardial revascularizations [15,16]. This intermediate state has been termed “myocardial hibernation.” Although most cases of myocardial dysfunction resulting from CAD are probably irreversible when due to infarction and subsequent deleterious ventricular remodeling (ischemic cardiomyopathy) , some patients with hibernating myocardium have been shown to experience a doubling of resting ejection fraction with resolution of congestive heart failure after coronary revascularization [18,19]. However, in most cases of hibernation, a more modest improvement in ejection fraction of 5% occurs after revascularization .
2. Diastolic dysfunction
Isolated diastolic dysfunction is the cause of heart failure in 10% to 30% of affected patients. This disorder is common in older patients with hypertension and often is suspected because of echocardiographically detected concentric left ventricular hypertrophy, normal systolic function and abnormal transmitral flow velocity patterns . However, in some patients with normal systolic function, the abrupt onset of pulmonary edema raises the suspicion that transient ischemia was the cause of decompensation, because elderly patients with hypertension have, by definition, at least two risk factors for coronary disease. In these patients, who are often too ill to undergo stress testing, coronary angiography may be necessary to establish or rule out the diagnosis of ischemically related diastolic dysfunction and heart failure.
Recommendations for use of coronary angiography in patients with congestive heart failure
Congestive heart failure due to systolic dysfunction with angina or with regional wall motion abnormalities and/or scintigraphic evidence of reversible myocardial ischemia when revascularization is being considered. (Level of Evidence: B)
Before cardiac transplantation. (Level of Evidence: C)
Congestive heart failure secondary to postinfarction ventricular aneurysm or other mechanical complications of MI. (Level of Evidence: C)
Systolic dysfunction with unexplained cause despite noninvasive testing. (Level of Evidence: C)
Normal systolic function, but episodic heart failure raises suspicion of ischemically mediated left ventricular dysfunction. (Level of Evidence: C)
Congestive heart failure with previous coronary angiograms showing normal coronary arteries, with no new evidence to suggest ischemic heart disease. (Level of Evidence: C)
1. Aortic dissection
The need for coronary angiography before surgical treatment for aortic dissection remains controversial because there are no large trials to support its use. In young patients with dissection due to Marfan syndrome or in dissection in peripartum females, coronary angiography is unnecessary unless there is suspicion that the dissection has affected one or both coronary ostia. In older patients, in whom dissection is usually related to hypertension, coronary angiography is often necessary, especially if patients are suspected of having coronary disease because of a history of angina or objective evidence of myocardial ischemia. In patients who have no history of coronary disease, the indications for coronary angiography are much less certain. Because of the high incidence of coronary disease in older patients with dissection, some studies have advocated routine coronary angiography , whereas others have found increased mortality when angiography is performed .
2. Hypertrophic cardiomyopathy
Significant CAD due to atherosclerosis is found in 25% of patients aged >45 years with hypertrophic cardiomyopathy . Because symptoms due to CAD and hypertrophic cardiomyopathy are similar, patients with ischemic symptoms not well controlled with medical therapy may require coronary angiography to resolve the cause of chest pain. Coronary angiography also is indicated in patients with chest discomfort and hypertrophic cardiomyopathy in whom a surgical procedure is planned to correct outflow tract obstruction.
Some patients with inflammatory processes affecting the aorta, such as Takayasu arteritis, may have coronary artery involvement requiring coronary artery revascularization. In such patients, coronary angiography is required before the surgical procedure. Kawasaki disease can result in coronary artery aneurysm and coronary artery stenosis producing myocardial ischemia or silent occlusion and may require coronary angiographic assessment [24,25].
4. Chest trauma
Patients who have an acute MI shortly after blunt or penetrating chest trauma may have atherosclerotic CAD, but coronary artery obstruction or damage has been reported in the absence of coronary atherosclerosis . Furthermore, myocardial contusion may simulate acute MI. Infrequently, coronary angiography is indicated in the management of such patients.
Recommendations for use of coronary angiography in other conditions
Diseases affecting the aorta when knowledge of the presence or extent of coronary artery involvement is necessary for management (e.g., aortic dissection or aneurysm with known coronary disease). (Level of Evidence: B)
Hypertrophic cardiomyopathy with angina despite medical therapy when knowledge of coronary anatomy might affect therapy. (Level of Evidence: C)
Hypertrophic cardiomyopathy with angina when heart surgery is planned. (Level of Evidence: B)
High risk for coronary disease when other cardiac surgical procedures are planned (e.g., pericardiectomy or removal of chronic pulmonary emboli). (Level of Evidence: C)
Prospective immediate cardiac transplant donors whose risk profile increases the likelihood of coronary disease. (Level of Evidence: B)
Asymptomatic patients with Kawasaki disease who have coronary artery aneurysms on echocardiography. (Level of Evidence: B)
Before surgery for aortic aneurysm/dissection in patients without known coronary disease.
Recent blunt chest trauma and suspicion of acute MI, without evidence of preexisting CAD. (Level of Evidence: C)
Cineangiographic images of coronary arteries have been the principal clinical tool for determining the severity of coronary luminal stenosis. Modern angiographic equipment has a resolution of four to five line pairs per millimeter with a six-inch field of view, the usual image magnification for coronary angiography . Validation studies that use known phantoms show a high correlation between actual size and that measured by quantitative coronary angiography (QCA) (r = 0.95) [29–32]. The resolution of these phantom studies indicates the precision of coronary angiography to be 0.02 to 0.04 mm. Factors that limit resolution in the clinical setting include grainy films from “quantum mottling” and motion artifact that, in a clinical setting, limit resolution to 0.2 mm, far less than that realized from static images of known phantoms. Other factors, such as angulation, overlap of vessels and image tube resolution can also influence accuracy in the clinical setting. Nevertheless, the accuracy of coronary angiography does allow for anatomic detail that is not obtainable by current noninvasive or other invasive technology. Only intravascular ultrasound, which is discussed in Appendix C, has an image resolution greater than that of coronary angiography. However, intravascular ultrasound cannot visualize the entire coronary tree nor define the anatomic course of the coronary vessels. It is also limited by shadowing from heavy calcification and by its inability to image very small vessels or very severe stenosis.
Recent advances in computer storage technology have made feasible digital acquisition, processing and archival storage of angiographic images obtained during cardiac catheterization. Widespread conversion from cineangiographic film to digital archiving and storage is anticipated during the next decade. Analog storage technologies such as super VHS videotape and analog optical disks have inadequate resolution to faithfully record coronary angiography. Digital storage methods are generally adequate but until recently have lacked standardization, which precluded easy exchange of digital angiograms between centers with different equipment. The development of the Digital Imaging and Communication standard (DICOM) for cardiac angiography ensures compatibility between equipment from participating vendors.
In the interventional era, the advantages of digital angiography are important. The image quality provided by digital angiography is better than any common videotape format. Improvements in computer speed and processing capability enable rapid replay of coronary injection sequences, as well as evaluation of the results of each intervention and identification of complications such as intraluminal thrombus and dissection. In many laboratories, the availability of high-quality images during catheterization permits diagnostic and therapeutic catheterization to consist of a single procedure, a capability with significant implications for the cost of interventional procedures. Industry sources now estimate that >75% of existing laboratories are equipped with digital imaging capability.
The ACC Cardiac Catheterization Committee is coordinating efforts to develop and promote a standard for archival storage and exchange of digital cardiac angiography. The committee has joined in this common cause with an industry organization, the National Electrical Manufacturers Association (NEMA), and representatives of the American College of Radiology (ACR). The ACR and NEMA have recently released an interim standard known as Digital Imaging Communication in Medicine (DICOM version 3.0).
The initial efforts of the standards committee have focused on adoption of a file format and physical medium for interchange of digital angiographic studies. To transfer images between medical centers, the sender would generate a DICOM-compatible file for review by the receiver. Recently, this working group has chosen a recordable form of the common CD-ROM, termed CD-R, as the official exchange medium. Nearly all equipment vendors have announced support for this format.
In clinical practice, the degree of coronary artery obstruction is commonly expressed as the percent diameter stenosis. This is done by comparing the diameter of the site of greatest narrowing (minimal lumen diameter) to an adjacent segment assumed to be free of disease. In clinical practice, the most common method used to estimate the percent diameter narrowing is subjective visual assessment. Because vasomotor tone can alter the reference diameter, nitroglycerin is frequently administered before angiography to improve the reproducibility of the measurement. Several studies have shown that measurement of the degree and extent of luminal narrowing correlates with symptoms as well as with assessments of coronary flow reserve (CFR) and abnormalities on treadmill exercise testing, perfusion imaging with Tl or sestamibi, stress echocardiography and fast computerized tomography [33– 37]. In addition, the percent diameter reduction and the number of stenosis of >50% to 70% correlate with long-term outcome [33–37].
Although coronary angiography is considered the reference standard for anatomic assessment of coronary obstructions, there are limitations to the technique. When luminal narrowings are present on coronary angiography (in the absence of spasm), pathological analyses almost always demonstrate severe atherosclerotic obstruction. Even minor angiographic abnormalities are associated with a poorer long-term outcome than are completely normal appearing angiograms. Coronary angiography has a high predictive value for the presence of CAD when abnormalities are present. However, the converse is not true. A normal coronary angiogram does not exclude atherosclerosis, and in fact, most pathological studies suggest that angiography grossly underestimates the extent and severity of atherosclerosis [38–42]. Several factors contribute to this discrepancy.
First, angiography depicts coronary anatomy from a planar two-dimensional silhouette of the contrast-filled vessel lumen. However, coronary lesions are often geometrically complex, with an eccentric luminal shape such that one angle of view may misrepresent the extent of narrowing . Two orthogonal angiograms should demonstrate more correctly the severity of most lesions, but adequate orthogonal views are frequently unobtainable because the stenosis may be obscured by overlapping side branches, disease at bifurcation sites, diographic foreshortening or tortuosity. This can be especially difficult in the left main coronary artery, where identifying a significant stenosis is of utmost clinical importance .
Second, an adaptive phenomenon, coronary remodeling,” contributes to the inability of coronary angiography to identify mild atherosclerosis . Remodeling was initially observed on histology as the outward displacement of the external vessel wall in vascular segments with significant atherosclerosis. In the early phases of atherosclerosis, this vessel enlargement “compensates” for luminal encroachment, thereby concealing the atheroma from the angiogram. When the atherosclerotic plaque becomes severe, luminal encroachment becomes evident. Although such mild lesions do not restrict blood flow, clinical studies have demonstrated that these minimal or even unseen angiographic lesions represent an important predisposing cause of acute coronary syndromes, including MI .
Third, assessment of luminal diameter narrowing is complicated by the frequent absence of a normal reference segment. Angiography visualizes only the lumen of the vessel and cannot determine if the wall of the reference segment has atherosclerosis [38–42]. In the presence of diffuse reference segment disease, percent stenosis will predictably underestimate the true amount of diameter narrowing.
Finally, in the setting of percutaneous intervention, the assumptions underlying simple projection imaging of the lumen are further impaired. Necropsy studies and intravascular ultrasound demonstrate that most mechanical coronary interventions exaggerate the extent of luminal eccentricity by fracturing or dissecting the atheroma within the lesion [45– 49]. The angiographic appearance of the postintervention vessel often consists of an enlarged, although frequently “hazy” lumen . In this setting, the lumen size on angiography may overestimate the vessel cross-sectional area and misrepresent the actual gain in lumen size.
Experimental and clinical studies have shown that when percent stenosis is >50%, the ability to increase blood flow in response to metabolic demands is impaired . This augmentation of coronary blood flow to demand is termed the coronary flow reserve. Determination of CFR requires measurement of blood flow at rest and after induction of reactive hyperemia, usually by administration of a coronary vasodilator. Several methods for measurement of CFR in patients have been developed, including intracoronary Doppler flow probes, digital angiography and quantitative PET [51– 54].
Coronary collaterals can provide significant additional blood flow to territories served by stenotic vessels . In general, collaterals are not evident unless resting ischemia is present, such as that which occurs with a stenosis.90%. In many patients, collateral flow merely restores normal resting blood flow but does not provide adequate flow when metabolic demand increases. The presence of collaterals, however, is associated with preservation of myocardial function after MI, reduced myocardial ischemia on noninvasive stress testing, and reduced ischemia during angioplasty [59,60]. Paradoxically, a greater ischemic response on noninvasive functional testing with adenosine than with exercise has been reported in the presence of collaterals, presumably due to an increase in the coronary steal phenomenon . Collateral blood flow can only be semiquantified by angiography , and precise assessment of perfusion by angiography is poor. This inability to adequately measure collateral flow is one of the factors that prevent accurate assessment of the functional significance of coronary stenosis by angiography alone .
For an understanding of the pharmacologic properties and adverse effects of contrast agents, the reader is referred to the 1993 review of the subject by the ACC Cardiovascular Imaging Committee  and the 1996 review by Hirshfeld .
Except for a less potent anticoagulant effect, nonionic agents are better tolerated and have fewer side effects than ionic agents . Several randomized trials have compared their use during cardiac angiography. Barrett et al.  compared a nonionic low-osmolar contrast agent with an ionic high-osmolar contrast agent. Although adverse events were reduced, severe reactions were confined to patients with underlying severe cardiac disease. These authors supported the use of nonionic low-osmolar agents in these high-risk patients. Steinberg et al. 
The difference in the incidence of any major contrast reaction is proportional to the New York Heart Association clinical function class, rising from 0.5% for class I patients to 3.6% for class IV patients . Given these observations, it has been suggested that nonionic agents should be reserved for patients who are at high risk for adverse reactions and that ionic agents should be used for all other patients .
Factors that have been associated with high risk of adverse reactions to contrast media include prior adverse reaction to contrast agents, age >65 years, New York Heart Association functional class IV (or hemodynamic evidence of congestive heart failure), impaired renal function (creatinine >2.0 mg/dL), acute coronary syndromes (unstable angina or acute MI) and severe valvular disease (aortic valve area <0.7 cm2 or mitral valve area <1.25 cm2) . It is recommended that the individual practitioner appropriately assess the cost and benefit relationship when selecting contrast agents in any individual patient and that a strategy of reserving nonionic agents for patients who are at high risk of adverse reactions is prudent and cost-effective.
ACC/AHA classifications of class I, II, and III. These classes summarize the indications for coronary angiography as follows:\n\t\t\t\t
Class I: Conditions for which there is evidence and/or general agreement that this procedure is useful and effective.
Class II: Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of performing the procedure. Class IIa: Weight of evidence/opinion is in favor of usefulness/ efficacy. Class IIb: Usefulness/efficacy is less well established by evidence/opinion. Class III: Conditions for which there is evidence and/or general agreement that the procedure is not useful/effective and in some cases may be harmful.[70,71]
Coronary angiography indications
Unstable angina or Chest pain [uncontrolled with medications or after a heart attack]
Before a bypass surgery
Abnormal treadmill test results
Determine the extent of coronary artery disease
Disease of the heart valve causing symptoms (syncope, shortness of breath)
To monitor rejection in heart transplant patients
Syncope or loss of consciousness in patients with aortic valve disease
Pain in the Jaw,Neck or Arm
Generally the risk of serious complications ranges from 1 in 1,000 to 1 in 500. Risks of the procedure include the following :
Irregular heart beats
Low blood pressure
Injury to the coronary artery
Allergic reaction to contrast dye
Rare risks and complications include:
Need for emergency heart surgery or angioplasty.
Surgical repair of the groin/arm puncture site or blood vessel.
Abnormal heart rhythm that continues for a long time. This may need an electric shock to correct.
An allergic reaction to the x-ray dye.
Other, less common complications include:
Arrhythmias. These irregular heartbeats often go away on their own. However, your doctor may recommend treatment if they persist.
Kidney damage caused by the dye that’s used during the test.
Blood clots that can trigger a stroke,heart stroke, or other serious problems.
Low blood pressure.
Coronary angiography contraindications
Kidney failure or dysfunction
Problems with blood coagulation (Coagulopathy)
Active systemic infection
Uncontrolled Blood Pressure (Hypertension)
Allergy to contrast (dye) medium
Transient Ischemic attack
Uncontrolled rhythm disturbances (arrhythmias)
Uncompensated heart failure
In recent decades, the wine sector has undergone major structural changes due to globalisation and increased international competition . It is a highly fragmented sector where exports from the traditional producer countries (France, Italy and Spain) are being challenged by new producers, such as Australia, California, Chile, Argentina and South Africa, the latter dubbed ‘New World Producers’.\n
Consumers are also changing globally. This is not only a geographic shift in terms of where exports are being directed, with the emergence of new markets such as China, but also a shift in terms of consumer tastes, whereby they are now opting for better quality wines and the satisfaction of more complex needs , something legitimate and linked to the cultural attributes associated with the product itself.\n
All these changes have had an impact on production, with numerous wineries, territories and countries battling to position their wines worldwide. Hence Denominations of Origin (DOs) are created, which help to certify the particular quality of wine products, whose production is limited to certain geographical areas, which in turn protects them from competition and fosters their promotion, status and international recognition. The most globally recognised DOs of sparkling wine are French Champagne, Spanish Catalan Cava and Italian Prosecco.\n
Although bottled still wine was the highest selling product worldwide in 2017, with a market share of 71% in value and 54% in volume, sparkling wines are gaining ground, with exports rising globally by 11.2% in volume and 8.9% in value; although they only represent 8% of the total exported volume, in terms of value that figure rises to 19% .\n
The main exporters of sparkling wine worldwide are Italy, with a market share of 41%, followed by France, with 24% and Spain with 22%. However, the average value of an exported bottle of Italian sparkling wine is €2.80, while that of Spanish sparkling wine is €1.84, and that of French is as high as €12.60, due to the high average price of champagne, €18.20 a bottle .\n
Champagne is a sparkling wine produced using the champenoise method whereby the second fermentation occurs inside each bottle, thus obtaining a superior quality product. Such high quality, status and global reputation make it the indisputable market leader. In 2017, global consumption of champagne amounted to 40% of the value and 13% of the volume of all sparkling wine, with France and the UK being the main consumer markets for this precious liquid .\n
Catalan cava is an alternative to champagne. It is made by the same production process as champagne, but the price is lower, so it is highly appreciated on the market for offering good value for money. Because of this, exports have grown exponentially since the 1990s to reach 162 million bottles in 2017, with sales led by the Freixenet and Codorníu companies.\n
Likewise, in recent years, Italian Prosecco has become one of the leading sparkling wines on the international market, regarded as a fashionable but cheaper alternative to French champagne. It costs less than champagne and cava because it is produced using the charmat method by which the second fermentation occurs in stainless steel tanks, which brings down production costs in comparison with the champenoise method. In 2016, Prosecco exports to the UK exceeded those of champagne in terms of value, and forecasts suggest it will become the fastest-rising sparkling wine in terms of worldwide sales [4, 5].\n
As for the main countries that import sparkling wine, the UK tops the ranking in terms of value, playing its part in the upward trend in sparkling wine consumption, with a 76% increase in sales from 2012 to 2017 . In 2015, 80.4 million litres of Italian sparkling wine were sold in the UK, followed by the 28 million litres of French sparkling wines and 20.2 million litres of Spanish sparkling wines [6, 7].\n
The Spanish wine sector, through the internationalisation of its wineries and designation of origin (DO) wines, is highly prestigious and internationally renowned. It is a key sector of the Spanish economy, culture and gastronomy, and has now reached full maturity . However, the economic crisis that began in 2007 led to a decrease in domestic sales and stock accumulation, leading many companies, especially SMEs, to begin or intensify internationalisation processes (ICEX, 2013).\n
In this chapter, we shall be analysing the visibility of websites when searching for Spanish cava or sparkling wine using the UK version of the Google search engine.\n
In consideration of technological progress and the increase in online sales, a recent report by the RAW agency on ‘The digital behaviour of Spanish wineries’  states that only two out of every 10 Spanish wineries get more than 10,000 visits to their website per month and in most cases these are limited to visits from inside Spain. In turn, a large proportion of Spanish wineries’ foreign sales are made through wholesalers, since most of their websites are not addressed at the international digital market or at direct sales of their products. All of this suggests that there is a huge opportunity for them to increase their sales through a greater presence in the digital market, especially in the UK market that tops the rankings for the online sale of alcoholic beverages.\n
Estimates of international traffic generated with the SemRush digital marketing instrument show that only seven of the 10 highest selling Spanish wineries receive traffic from the UK (Table 1).\n
|\n||\n||Spanish traffic (%)\n||UK traffic (%)\n|
Although the instrument does not define the types of traffic (whether it is direct, via social networks, via links in newsletters or via search engines), the purpose of our study is to measure a website’s visibility based on of the contents that appear on Search Engine Result Pages (SERPs).\n
The main objective of this study is to analyse the visibility of the Spanish sparkling wine brands on the UK version of the Google search engine, that is, to identify the websites that appear in the results of searches for ‘cava’ and thereby determine how well positioned Spanish cava brands are.\n
Our specific goals are:\n
1. Mapping of all websites visible on
2. Analyse the Google visibility of the websites of Spanish sparkling wine brands. By mapping, we are able to identify sparkling wine websites and classify them by nationality, in order to accurately measure the visibility of websites belonging to Spanish brands and/or with a Spanish IP address.\n
3. Analyse the
4. Analyse the visibility of retailers that appear in Google results and which offer Spanish sparkling wine brands, from specialist stores to major supermarket chains.\n
Bearing these objectives in mind, the research questions that this study will be looking to answer are the following:\n
RQ1. What kind of information does
RQ2. What is the relative weight of the websites of Spanish sparkling wine brands in
RQ3. What media, social networks and sector websites are shown by Google when searching for Spanish sparkling wines from the UK? What is their relative weight?\n
RQ4. Which are the main e-commerce websites in terms of their visibility?\n
It is well known that the vast majority of Europeans routinely use search engines to access the information available on the web, and that the links appearing on SERPs are their main point of access to the web immediately after performing a search using their search engine of choice. In the UK in 2018, Google had a market share of 89.1% of all searches made on search engines, thereby acting as gatekeeper  in terms of access to information, meaning that its search engine results pages are the best showcase for companies seeking to promote their products or services.\n
Search engine results pages (hereinafter SERPs) are one of the central objects of study in Search Engine Optimization (SEO), because they reveal what Google ‘considers’ to be the best possible response to the searches made by users, and if a website is viewed by Google to be one of the best answers to a query, that page will be ranked high on SERPs and will therefore benefit from the enormous flow of traffic that stems from being in the top positions.\n
At first, Google’s SERP offered 10 organic results, that is, 10 links to web content that had previously been located by Google crawlers and that the search engine ordered by how relevant they were to its algorithm’s criteria. However, since the incorporation of the Google Universal and Blended Results algorithm , its SERPs have undergone constant change and currently consist of a variety of elements that appear along with the 10 original organic results. These elements include images, videos, news, local results, social network content and special results generated by the search engine itself based on web content that it has been discovered during its page crawling and indexing processes. The most prominent of these elements include the Knowledge Graph , ‘One Box’ responses and, since 2018, the ‘Related Searches’ that appear in more than 80% of the searches we make.\n
However, despite the many elements that the search engine displays on its results page, as many as 84% of clicks are concentrated in the first four results , which makes the highest part of the SERP an extremely competitive space, not only for the websites that are looking to gain traffic by appearing in the top results, but also for the search engine itself, which fills up much of this space with its own elements.\n
With the aim of cataloguing and measuring the visibility of contents appearing on SERPs when performing searches related to Spanish cava and sparkling wine, the following study analyses SERP composition using the Infosphere model proposed by Peretti  and Bennett . This media ecology applied as an open system of categorisation  can classify any content and measure its weight and importance on SERPs using a system composed of three well-differentiated and clearly identifiable strata, namely:
The Conventional Layer corresponds to the media and is made up of cybermedia, meaning both the conventional press, and any other newspaper or magazine that is published on the web.
The Middle Layer consists of millions of websites and includes leading domains on any subject.
The Micro Layer includes social networks and the blogosphere.
Each of these layers contains different sectors and conglomerates, groups of domains that all share a characteristic sector or theme. The system includes a database of websites thanks to which it is possible to identify and measure the proportion of websites appearing on SERPs individually or together with other sites in the same category. In addition, as it is an open system, the database can be expanded with new thematic conglomerates depending on the nature of the research, as we have done with our sample.\n
This research is a longitudinal study over a period of time that analyses the composition of the SERPs shown by Google when we search for a specific topic, in our case related to the Spanish sparkling wine. The study combines quantitative and qualitative methodologies to analyse a series of samples of potentially visible SERPs in searches conducted from the UK. The qualitative analysis allows us to recognise different types of results shown by Google in its SERPs, as well as the different types of websites depending on their characteristics and themes. On the other hand, a quantitative analysis is applied to the categorisation derived from the qualitative analysis, thanks to which we can measure the weight of any of the sample categories.\n
Thus, the present study analyses a sample of
Using the Google Ads ‘Keyword Planner’ tool, previously known as Google Adwords, we were able to extract lists of keywords related to any term along with its monthly frequency in the last 4 years. The interface can be used to select any country in the world and extract results that are broadly or closely related to the initial search term.\n
In order to find out the search frequency of the different terms associated with this search niche, we checked four ‘seed terms’ in the planner: on the one hand, the term ‘cava’ together with its biggest French and Italian competitors, ‘champagne’ and ‘prosecco’, and on the other hand, the generic term ‘sparkling wine’.\n
These four initial terms, after several iterations, produced a total of 2280 queries that had gathered an average of 481,640 searches per month during the previous 4 years.\n
There were 752 retrieved queries including the term ‘prosecco’, which accumulated an average of 215,000 searches a month, followed by those that include the term ‘champagne’, of which there were 691, but which accumulated a higher average of around 224,000 searches a month. At a considerable distance behind, we were able to identify 289 searches that included the term ‘cava’ and which accumulated around 22,000 searches per month, a lower figure than the 682 queries in which the term ‘sparkling’ appeared, which accumulated about 24,000 searches per month. Also, and to a lesser extent, 42 related terms were identified that include the term ‘fizzy’ and accumulated about 1500 searches a month (see Table 2).\n
|Seed term\n||Number of retrieved queries\n||Searches per month\n|
In the aforesaid large groups, we can find searches that include more than one of the national terms that we use to describe sparkling wine. Searches that include ‘champagne’ and ‘prosecco’ have an average monthly frequency of 2610 searches, followed by those featuring the term ‘champagne’ together with ‘cava’ with 700 searches a month and ‘cava’ and ‘Prosecco’ with 640.\n
Once the keywords had been retrieved, we selected a subset of 24 representative terms, including the term ‘cava’ along with various search modifiers, which we proceeded to use as the main terms for extracting Google UK search engine results, both organic and those paid for using the Google Ads service. Table 3 shows the keywords used along with their monthly and accumulated average frequency for the years 2016–2018.\n
|Keyword\n||Searches per month\n||2016\n||2017\n||2018\n|
|Spanish sparkling wine\n||1300\n||11,720\n||13,150\n||19,820\n|
|Bottle of cava\n||140\n||1450\n||1350\n||1570\n|
|Spanish fizzy wine\n||40\n||790\n||320\n||280\n|
|Cava sparkling wine\n||70\n||680\n||540\n||730\n|
|Spanish cava brands\n||40\n||490\n||360\n||420\n|
|Cava Spanish wine\n||20\n||320\n||170\n||270\n|
|Best Spanish cava\n||10\n||240\n||170\n||160\n|
|Spanish sparkling white wine\n||30\n||230\n||320\n||560\n|
|Spanish sparkling wine list\n||10\n||180\n||110\n||80\n|
|Spanish champagne cava\n||10\n||140\n||110\n||110\n|
|Spanish sparkling red wine\n||10\n||100\n||100\n||100\n|
|Best cava sparkling wine\n||10\n||90\n||60\n||70\n|
|Cava sparkling wine brands\n||10\n||70\n||40\n||40\n|
|Spanish sparkling wine brands\n||10\n||60\n||70\n||70\n|
|Spanish sparkling wine cava\n||10\n||110\n||120\n||110\n|
As mentioned before, we start from a database of more than 60,000 sites, which include media websites from different countries, the most popular online social networks, as well as relevant sites and blogs on a variety of topics. We can use this database to take any sample of results and identify and measure those that belong to the Conventional Layer or the Micro Layer. Depending on the subject of the seed terms, each new capture of results presented new websites that had not been identified previously and that needed to be categorised.\n
The new capture of results with a set of terms related to cava allowed us to locate unknown websites that are categorised via a semi-automatic process that recognises the type and topic from the domain name, elements of the Uniform Resource Locator (hereinafter, URLs) and the metadata that we extract afterwards. These new websites mostly belong to the Middle Layer, especially when the thematic niche had not been mapped before.\n
Once the keywords had been selected, we applied Search Engine Optimization (hereinafter, SEO) tools to extract the
The data capture period lasted for 29 weeks from May to November 2018 (see Table 4), resulting in a sample of 72,302 organic results taken from
To measure and analyse the size of the different sectors and conglomerates, we have a database of previously categorised sites, a pre-established group of homogeneous conglomerates common to samples from different niches (press, social networks, government websites, etc.). However, during this data capture process, new sites were discovered and to categorise them, new conglomerates were created that fit specific types of websites that appeared in our sample, such as international sites of sparkling wine brands, liquor stores, websites and blogs on the wine world and a series of lesser sites that showed up in the sample. In this case, a database of national and international websites linked to the wine world was developed that includes more than 4000 Spanish wineries and thousands of websites and blogs.\n
Then all the results with visibility were categorised by layer, sector and conglomerate, followed by analysis of the complete dataset according to type of site, which of these categories they belong to and their position.\n
All the visibility calculations were performed on Excel spreadsheets, and dynamic tables were used to analyse the subsets of data.\n
To summarise, the following process was observed in order to answer the research questions:
Extraction of a list of searches made from the UK related to sparkling wine and cava using the keyword research features of the Adwords and SEMrush instrument.
Selection of a set of 24 representative searches.
Scraping of the first five pages of results of each search on
From the resulting package of SERPs, the URLs were extracted and the domain names to which they belong were isolated.
The domains were categorised by type and grouped into homogeneous conglomerates.
The composition of the results of the sample was analysed.
The top five SERPs for each term were retrieved using scraping processes, extracting a sample of 74,495 URLs from
The first research question asked what kind of information
Table 5 shows the distribution of results by device used and the type of content that appeared in the Top5 SERPs. Most of the retrieved contents are organic results, 77.23% of the total, followed by images with 7.73%, Accelerated Mobile Pages (AMP) only detected on Mobile with 7.15%, and Related Questions with 5.98%.\n
|Type of content\n||\n\n||%\n||\n\n||%\n||Total\n||%\n|
The weight of the remaining content is considerably lower, as shown in Table 5. Videos, mostly from YouTube, account for 1.08% of the total, and ‘One Box’ only amounted to 0.75%.\n
The aforesaid proportions change substantially when we focus on the results that appear in the visible part of the SERP, that is, the top four results. Table 6 shows the same distribution as in the previous table but only for the Top4.\n
|Type of content\n||\n\n||%\n||\n\n||%\n||Total\n||%\n|
When analysing this sample we note that the organic results represent only 32.79% of the results (28.74% on mobile and 36.85% on desktop) and the remarkably high visibility achieved by the Related Questions section in the top part of the SERP with an average of 43.86%, while that figure rises to 48.96% in the desktop version. The sample hence evidences the visual preponderance of these questions generated by Google over the other contents, even above the organic results.\n
Next, we applied the different Infosphere levels to the sample of results for the Top4, which allowed us to group the different websites according to which of the three main layers they belong to, and at a lower level by grouping them into sectors and conglomerates (see Table 7).\n
|Strata > sectors > conglomerates\n||\n\n||%\n||\n\n||%\n||Total\n||%\n|
|1. Conventional Layer\n||1424\n||51.15\n||1721\n||61.82\n||3145\n||56.48\n|
|2. Middle Layer\n||1104\n||39.66\n||829\n||29.78\n||1933\n||34.72\n|
|Food and drink\n||335\n||12.03\n||258\n||9.27\n||593\n||10.65\n|
|3. Micro Layer\n||256\n||9.20\n||234\n||8.41\n||490\n||8.80\n|
On the first level of analysis, we distinguish the three layers into which the Infosphere model is divided. The results from the Conventional Layer make up 56.48% of the total (3.145 URLs), followed by the Middle Layer with 34.72% (1.933 URLs) and the Micro Layer with an average of 8.80% (490 URLs). However, we note that the proportions of the first two layers vary considerably in terms of Mobile and Desktop results, with a difference of 10 points more for media content in the Desktop version.\n
On the next level of analysis, we find a subcategory called Sector that encompasses sites that share common characteristics either in terms of sector or topic. In the Conventional Layer, we find two very distinct sectors, results coming from the press on the one hand, and results generated by Google on the other. On this level, we observe that the results generated by the search engine accumulate 43.89% compared to those by the press, which only amount to 12.59%. The most prominent sectors in the Middle Layer include the group of sites dealing with e-commerce (14.03%), followed by websites on various topics (13.06%) and sites about the wine sector (6.72%).\n
Finally, we calculated the proportions on a conglomerate level, where 43.89% of the search engine’s results are ‘Related Questions’, followed by the British Press conglomerate with 12.07%. In third place, we find the Middle Layer conglomerates that group food and drink websites with 10.65%, followed in fourth and fifth place by the conglomerates that group Supermarkets and Liquor Stores with 8.21 and 3.95%, respectively.\n
Focusing now on the second research question that enquires about the weight of the websites of Spanish sparkling wine brands in
|Cava brands\n||\n\n||Average ranking\n||%\n||\n\n||Average ranking\n||%\n|
There is no brand of cava that appears in the Top4, and in the case of Freixenet, despite the fact that the domain
These average URL rankings of the 10 Spanish brands in 25–46th place out of 50 confirm the information published by the RAW agency on the digital behaviour of Spanish wineries, claiming that they have not been launched onto the digital market. This is why we advise these companies to work to get their websites into the Top10 of Google search engines, through SEO optimization or payment for keywords to appear in SEM, and thus achieve greater international visibility for their brands and products, focusing first on the international markets where the company has the highest sales and, secondly, on developing markets where there are good sales prospects.\n
The third research question asked what media, social networks and wine sites are retrieved by Google when searching for Spanish sparkling wines from the UK and what their weight is.\n
After performing an analysis of the media that appear in the Top4
In a prominent second place, we found the
From this analysis, we observed that these Spanish cava companies’ marketing plans do not include public relations or advertising actions with these media, since their visibility is very limited.\n
Regarding the visibility of social networks in searches related to cava or sparkling wine (see Table 10), we should note that only
These results suggest that Spanish cava companies do not prioritise communication of their products on the web pages shown in Table 10 and from which they could obtain much better visibility among British users.\n
As shown in Table 11, the leading wine website in terms of visibility is
The fourth and final question asks what the main e-commerce websites are in terms of their visibility.\n
As we mentioned earlier, by mapping websites on the sample of results, we can measure the visibility of any website whose contents are visible on Google SERPs. The database resulting from this mapping procedure includes a series of e-commerce sites that we classified into three different conglomerates based on the products offered. So, we have a first conglomerate where all the results from
The analysis also shows that the e-commerce domain that appears most frequently and has the best SEO rankings is
In this chapter, we have quantified a representative set of queries related to sparkling wine used by British users when searching for information on Google. From this set of queries, we have selected the ones that are directly linked to cava and extracted search engine results for a 29-week period so as to generate a database of all visible websites on
Using the Google Ads Keyword Planner instrument, we retrieved the monthly frequency of a set of queries related to sparkling wine that include the generic term ‘sparkling’, the word ‘cava’, or the names of its direct competitors, namely ‘champagne’ and ‘prosecco’.\n
From analysing this frequency data, we could confirm the rising tendency of the term ‘prosecco’, which is the most in-demand sparkling wine on international markets and the one that accumulates the highest number of queries in the UK; we also confirm the hegemony of ‘champagne’, which accumulates the highest number of searches a month, with searches for ‘cava’ and ‘sparkling wine’ in third and fourth place.\n
After this initial analysis, a set of 24 keywords related to Spanish sparkling wine were selected and SEO techniques were applied to extract the URLs that are shown when British users search using these keywords. The result was a sample of URLs and websites with which we could map all the websites that are visible on
Based on this mapping of results from
This is how we were able to measure the visibility of the websites of Spanish sparkling wine brands, noting that no cava brand is ranked in the Top4, and that the site with the highest visibility,
Likewise, all the web contents that appear in the results have been identified, especially those belonging to the media, social networks, wine websites and e-commerce sites. These data can be used as the basis to suggest content strategies that will gain visibility in the search niche, and offer guidance on where Spanish brands should focus in order to increase their visibility among British users and overcome barriers for the sale of wine.\n
Finally, we should stress that the mapping of websites in the sector shows what contents are chosen by the Google algorithm from among thousands of possible candidate sites. This selection showcases the best contents that any winery should take into account when creating their digital identity.\n
As a final conclusion, we could comment that if Google’s Consumer Barometer mentions that ‘By understanding what consumers look for, businesses are able to ensure the right information is available on their websites’, by understanding what results appear on Google, we can make the contents available on cava websites visible from any search engine.\n
The managerial applications derived from this study are aimed at improving the marketing strategies of Spanish wineries. The results of the research can help to optimise a company’s digital identity and lead to a variety of actions aimed at improving not only the visibility of its website but also sales of products.\n
The following are four particular actions derived from this study whose real application will help to boost the ranking of cava brands and products.\n
Our first recommended action is to improve SEO strategies, that is, optimise websites to position their contents at the top of SERPs and thus achieve greater international visibility for brands and products. Brands should first focus on the international markets where the company has the highest sales and secondly, on developing markets where there are good sales prospects.\n
The second action is aimed at improving knowledge about consumers through search engine analysis. On the one hand, quantitative analysis of the frequency of Google queries related to cava, champagne and prosecco can be used to measure the level of relative and absolute interest in these three products that compete not only in the British market but also on a global scale. On the other hand, qualitative analysis of long-tail queries offers specific details about the perception of cava, prosecco and champagne among the population of any country.\n
The third action is directly related to improved website visibility, as knowledge of the ranking and level of optimisation of a website can reveal whether the content marketing plan is working in a certain market. That is why this third action is based on finding out what types of content are preferred by Google, which will help us to develop optimised content strategies based on the data extracted from the sample.\n
In the case of cava, it has been detected that
In conclusion, we are able to make recommendations to improve the digital identity of cava brands aiming to gain visibility in a specific market.\n
This study is not free of limitations. First, the selection of a single national search engine tells us about the visibility of Spanish sparkling wine sites in that specific country, but the results cannot be extrapolated to markets other than the UK. Secondly, although the AWR instrument can be used to select IPs from a specific country, the personalization of Google results based on the user’s location can cause variations in the rankings and proportions of results for the same search. It would therefore be advisable to perform the data extractions from different locations in the UK and compare the results. Thirdly, constant modifications to Google’s ranking algorithms can cause considerable variations in the results, so this study is only valid in the short or medium term. Therefore, the recommendations derived from these analyses need to be adjusted to further monitoring of the Google rankings over time in order to cater for evolutions in terms of results.\n
Future research derived from this study includes increasing the sample size by expanding the list of analysed terms and/or analysing a higher number of locations.\n
This study was conducted on the basis of a limited group of searches, that is, a set of keywords limited to 24 generic terms related to cava and Spanish sparkling wine. However we could expand the list of terms in different ways by adding new combinations of keywords belonging to the same semantic field.\n
For example, we could add new generic searches related to the different types of cava and their variants (‘cava’ + ‘type of grape’ / ‘cava’ + DO / ‘cava’ + ‘brand’ / ‘cava’ + ‘name of supermarket’, ‘cava’ + ‘search transaction modifiers’) and measure the exact, real-time visibility of Catalan sparkling wine brands in Google results viewed from the UK or from any other country. Another option would be to use a set of keywords that includes terms related to wine tourism in Spain, which would allow us to measure the visibility, from any country in the world, of websites selling trips to Spanish vineyards.\n
The exercise could also be replicated with new sets of keywords using generic searches related to ‘champagne’ and ‘prosecco’, in order to measure the visibility of Italian and French wineries in the UK or on any other search engine.\n
As well as keywords, we could also increase the number of locations in the UK in order to measure deviations from this data capture, or choose any other Spanish wine-buying market by selecting different Google search engines designed for specific countries or cities.\n
Also, and in a similar way to what the SEMrush instrument does, at present we can only estimate the traffic from
In the long term, with a large database both of terms and sector websites, an observatory of the wine search niche focused on measuring Spanish websites in potential importer countries could be created.\n
This research has been carried out under the project eMarketwine (CSO2016-78775-R), financed by the Spanish Minister of Economy.\n