Perspective Chapter: The ProtekDuo® Cannula for Acute Mechanical Circulatory Support

Abstract

The ProtekDuo® is a dual lumen cannula that can be used in numerous configurations to treat cardiogenic shock and hypotension. Its default function is as a temporary percutaneous right ventricular assist device (RVAD) system, however, other configurations both alone and with other mechanical circulatory support (MCS) devices have evolved. In addition to its use as a component of a ventricular assist device (VAD), it can be used as a cannula for extracorporeal membrane oxygenation (ECMO) and may serve as double lumen drainage cannula on cardiopulmonary bypass (CPB). The role of the cannula in ECMO has been described in multiple configurations including traditional veno-pulmonary (V-P) or “oxygenated RVAD” (oxyRVAD), veno-venopulmonary (V-VP), or venopulmonary-arterial (VP-A). This book chapter summarizes various configurations and technical aspects of the ProtekDuo(R) cannula in the management of hypotension and cardiogenic shock.

1. Introduction

Despite improved treatment and outcomes for many forms of cardiovascular disease, cardiogenic shock (CS) remains a common cause of mortality [1, 2, 3]. CS is classically recognized as a state of inadequate cardiac output, which if left uncorrected, may lead to tissue malperfusion and organ failure. Vasopressors and inotropes become necessary as conventional treatment options to maintain adequate organ perfusion [4].

Over the past decade, only marginal improvements have been noted in outcomes and mortality rates of CS. When complicated by acute myocardial infarction (AMI-CS), the mortality rate ranges from 50 to 60%, while mortality from acute decompensated heart failure-related CS is approximately 40% [5].

Whether due to impaired function of the right ventricle (RV), left ventricle (LV), or both, implementation of prompt medical management to correct low cardiac output and hypotension is necessary. However, when medical management fails, use of acute mechanical circulatory support (MCS) should be considered [2]. In this chapter, we focus on a particular device, the ProtekDuo® cannula, and its role in the management of patients with cardiogenic shock with acute RV failure. We also discuss its evolving roles in the treatment of LV and biventricular failure, both alone and in combination with other devices, as well as use in the treatment of combined cardiac and respiratory failure, which commonly co-exist in clinical practice.

2. Cardiogenic shock

Cardiogenic shock occurs most frequently as a result of acute myocardial infarction (MI) [6], though any disease process that impairs the functional capacity of the left ventricle (LV) or right ventricle (RV) can lead to cardiogenic shock [1]. For years, numerous definitions and clinical criteria for cardiogenic shock have existed [7, 8, 9, 10], but in 2019 the Society for Cardiovascular Angiography & Interventions published a consensus statement on the classification of cardiogenic shock [2] that has been useful for assessment of patients as well as predicting outcomes [11]. In this consensus document, stages of cardiogenic shock are described based on physical exam findings, biochemical markers, and hemodynamic parameters [2]. A standardized, team-based approach to management of cardiogenic shock has been recommended due to the complexity of disease and number of treatment options [12]. Though a complete discussion of cardiogenic shock is beyond the scope of this chapter, a brief discussion of LV and RV failure follow.

2.1 Left ventricular failure

Numerous diseases can cause LV failure and cardiogenic shock though the most common are acute MI and acute decompensation of end-stage heart failure [3, 6]. In the setting of acute MI, there is impairment of regional myocardial contractility, which if significant, can become self-perpetuating as a result of further worsening coronary ischemia [6, 13]. Patients with chronic, end-stage heart failure may enter into an acutely decompensated state and progress to cardiogenic shock due to a number of factors including disease progression, medication or treatment non-adherence, or an acute cardiac insult [3]. Numerous other conditions can also lead to acute LV failure including, but not limited to, acute myocarditis, stress cardiomyopathy, and post-cardiotomy syndrome [13].

Management of cardiogenic shock with predominant LV failure begins with prompt recognition based on clinical criteria followed by a team-based approach to assessment including echocardiogram and hemodynamic values [12]. If acute MI is suspected or confirmed, a coronary angiogram should be performed with revascularization if able [13]. Patients are treated with inotropes and vasopressors to maintain adequate cardiac index and blood pressure. Failure to achieve goals with medications alone should prompt consideration of acute MCS [1, 12].

2.2 Right ventricular failure

Right ventricular failure is a complex clinical syndrome of fluid overload, low systolic function and cardiac output, and atrial or ventricular arrhythmias [14]. The two pathophysiologies of RV pressure and volume overload typically occur as a result of injury or stress and can occur alone or in combination to cause acute RV failure and reduced cardiac output [14, 15]. Acute rise in RV afterload can occur in the setting of acute pulmonary embolus or subacutely in the acute respiratory distress syndrome due to prolonged hypoxia and/or respiratory acidosis. Acute reductions in right ventricular contractility can occur from either ischemic etiology such as MI or from inflammatory etiologies such as myocarditis. Patients may also have chronic RV failure for which they are normally able to compensate yet may become acutely decompensated in the setting of additional increases in RV afterload or reduction in RV contractility [14, 16, 17].

Medical management of acute RV failure begins with fluid volume management, enhancing myocardial contractility, and optimizing RV afterload often with echocardiographic and pulmonary artery catheter (PAC) guidance [2, 13, 15, 17, 18]. Additionally, for patients with hypotension, peripheral vasopressors and inotropes may be required. If the shock state does not resolve with medical management, utilization of acute mechanical circulatory support (MCS) must be considered. Acute RV failure is a major cause of morbidity and mortality [17], thus timely evaluation and initiation of acute MCS is essential [15, 16].

Acute MCS can be used as a bridge to recovery for up to 75% of patients with acute RV failure [16], or if recovery is not possible, a bridge to durable assist devices or heart transplant. Multiple acute MCS devices capable of directly or indirectly bypassing the failed RV are available [16, 17]. In this chapter we will focus particularly on the ProtekDuo® cannula as a component of a right ventricular assist device (RVAD) system.

3. ProtekDuo® cannula

The ProtekDuo® is a single-site, dual-lumen cannula that is most commonly placed in the right internal jugular vein (IJV). When in its intended position, the cannula drains blood from its proximal ports in the right atrium and blood flow is directed through an extracorporeal circuit with or without oxygenator before being returned via the distal ports into the pulmonary artery. The cannula is available in two sizes, 29 and 31 French (Fr.) Placement in the IJV allows for ambulation of the patient. The percutaneous placement of this device has allowed it to be a less invasive support option in patients requiring mechanical (RV) support. See Figure 1.

Figure 1.

a: Percutaneous right ventricular assist device (RVAD) with a Protek Duo cannula. b: Without oxygenator, and c: with oxygenator. From: Condello, I. Percutaneous right ventricular assist device, rapid employment in right ventricular failure during septic shock. Crit Care 24, 674 (2020).With kind permission from Critical Care (Open access).

3.1 ProtekDuo® cannulation technique

Placement of a ProtekDuo® involves use of the modified Seldinger technique. Initially the right IJV is assessed for adequate size and an 8-Fr to 9-Fr introducer sheath is placed. Using the sheath, a balloon tipped catheter is guided and placed into the right pulmonary artery (PA) under fluoroscopy. Then a long 0.035-inch Lunderquist Extra Stiff Wire Guide (Cook Medical, Denmark) is guided through the balloon tipped catheter under fluoroscopic guidance and inserted into the right PA. The balloon-tipped catheter is then removed carefully under fluoroscopic guidance to ensure that the stiff wire remains in place in the right PA. Then the neck sheath is removed, and the site is progressively dilated to a size below the size of the cannula being used. A heparin bolus, dosed to achieve an activated clotting time of 300 seconds is given and then the ProtekDuo® cannula is placed under continuous fluoroscopy with the goal of having the cannula outflow port in the main PA [19]. Alternative anticoagulation may be achieved with direct thrombin inhibitors (DTI) [20], such as argatroban [21] or bivalirudin [22].

Transesophageal echocardiography (TEE) is useful to verify position of the cannula in the PA if fluoroscopy is not available. Both ports are clamped and then a wet-to-wet connection is made with the drainage and return ports. Pump flow is increased per the clinician’s discretion. The device is secured in place with a purse-string suture around the insertion site. Direct suturing to cannula body should be avoided as it may provoke erosion of the cannula wall. Suture rings are provided with the cannula which enable indirect fixation.

Once flow is initiated, a heparin or DTI infusion is initiated to maintain a partial thromboplastin time of 40-60 seconds, depending on the circuit used, which can later be adjusted to institutional protocols [19].

3.2 ProtekDuo® cannulation complications

There is limited data about ProtekDuo® related complications. Some authors have reported vascular injury during insertion, cannula thrombosis and cannula migration requiring repositing, but the occurrence of these seems to be low [23, 24, 25, 26]. Additionally, there is also a case report about right coronary artery compression caused by the cannula which was resolved by repositioning [27] and a case series of superior vena cava syndrome in two patients [28].

3.3 Device weaning

Patients should be evaluated daily for readiness-to-wean from support with the ProtekDuo cannula® once myocardial recovery occurs in addition to improvement in hemodynamic parameters including [29, 30]. While no standardized protocol currently exists for device weaning, recommended strategies include incremental reduction of device flow by 0.5 L/min until flow is at 2 L/min [29, 30]. Once device flow is low, assessment of hemodynamic parameters as well as ventricular function by echocardiography and laboratory parameters such as lactate are performed [29, 30]. If needed, low doses of vasopressors or inotropes can be used to provide hemodynamic support [29]. If weaning parameters are acceptable, then device removal can be considered if appropriate [29, 30].

4. ProtekDuo® as a ventricular assist device

The ProtekDuo® cannula, when placed in the intended location and connected to an extracorporeal pump, is able to provide direct bypass of the RV. As clinicians have become more experienced with using the cannula, its use has been adapted to other situations where ventricular assistance is needed.

4.1 ProtekDuo® as an RVAD

In studies of RVADs as treatment for acute RV failure, survival has improved with earlier initiation of mechanical support [16, 23, 26, 31]. RVADs can be inserted surgically, via sternotomy or thoracotomy, or percutaneously. Most RVADs, especially the percutaneous type, are intended for temporary use. The ProtekDuo® cannula is a particularly advantageous component of a percutaneous RVAD system as it allows for expedient, upper body, percutaneous access with a single cannula, thus avoiding surgical implantation and explantation via sternotomy. See Figure 1b.

Use of the ProtekDuo® cannula as a component of an RVAD has been increasingly reported in the literature since its approval for use in humans in 2016. Retrospective cohort studies, case reports, and case series have described its use alone for isolated acute RV failure as well as in combination with a left ventricular assist device (LVAD) for biventricular support in the setting of concomitant left ventricular failure [23, 24, 26, 32, 33, 34, 35].

4.1.1 ProtekDuo® for isolated acute RV failure

Acute RV failure can occur due to multiple etiologies including after temporary and durable left ventricular assist device (LVAD) implantation [23, 35], primary graft dysfunction after heart transplant [36], myocardial infarction [32], as well as other causes [24, 26, 33, 34].

Nicolais and colleagues [37] were among the first groups to report a larger series of patients with acute RV failure treated with the ProtekDuo®. In the series of 13 patients; four had acute myocardial infarction; three were bridge to lung or heart transplant; two had severe pulmonary hypertension; and one patient each had acute myocarditis, post-LVAD RV failure, or post-heart transplant graft dysfunction. The group reported a median duration of support of 6 days and 54% survival to device explantation. They concluded that the ProtekDuo® cannula could be used for short-term isolated RV support or in conjunction with a left ventricular support device for cases of biventricular failure while using single-site access [37].

Kremer et al. [32] conducted a retrospective study of 10 patients with acute myocardial infarction complication by acute RV failure who underwent ProtekDuo® implantation for RVAD support. Patients had significant reduction in right heart filling pressures and increase in cardiac output after device implantation. The mean duration of RVAD support with ProtekDuo® was 10 ± 7.4 days. The authors reported a 30-day and 1-year survival of 60% with four patients having complete recovery and two patients requiring placement of durable RVAD. A total of four patients required an interposed membrane oxygenator and there were no device-related complications. The authors concluded that the use of the ProtekDuo® cannula as a temporary RVAD was safe and feasible for patients with acute RV failure secondary to myocardial infarction [32].

Badu et al. [24] conducted a retrospective cohort study of 40 patients with acute RV failure grouped by primary cause: post-cardiotomy (n = 18), other cardiac causes including myocardial infarction and exacerbation of heart failure (n = 12), and severe respiratory failure (n = 10). The authors reported a significant reduction in vasopressor and inotrope requirements in all groups within 48 hours of device implantation. Device-related complications were reported including cannula migration in three patients, SVC syndrome in three patients, and right internal jugular vein thrombus in one patient. The authors reported duration of RVAD support with ProtekDuo® for patients who successfully weaned from support and patients who died on support. For patients who successfully weaned, the overall duration of support was a median of 14 days with patients in the post-cardiotomy group requiring support for a median of 15 days, other cardiac causes group 11 days, and respiratory failure group 10 days. For patients who died on support, the overall duration of support was a median of 5 days with patients in the post-cardiotomy group requiring support for a median of 43 days, other cardiac causes group 3 days, and respiratory failure group 15 days. The authors reported overall survival to discharge of 68% in the cohort. When survival to discharge was analyzed by cause of acute RV failure, the authors reported 89% survival in the post-cardiotomy group, 42% survival in the group of other cardiac causes, and 60% survival in the group with respiratory failure. The authors concluded that use of the ProtekDuo® cannula resulted in improved hemodynamics with reduced need for vasopressors and inotropes as well as high rates of weaning, low complications, and low mortality [24].

Oliveros and colleagues [34] conducted a retrospective study of 11 patients with acute RV failure from multiple causes including post-partum cardiomyopathy (with biventricular failure requiring simultaneous V-A ECMO support), following lung transplant, massive pulmonary embolism, myocardial infarction, and acute respiratory distress syndrome. The mean duration of RVAD support with ProtekDuo® was 58 ± 47 days. The authors reported 30-day survival of 82% and 180-day survival of 73%. The authors did not report device-related complications for the cohort [34].

Carrozzini et al. [36] reported a case series of three patients with acute RV failure due to primary graft dysfunction after heart transplant. Of note, all three patients required V-A ECMO prior to transplant due to end-stage biventricular failure. The authors reported complete unloading of the failed RV without distention of the LV by transesophageal echocardiogram. One patient experienced a right internal jugular vein thrombus. The patients required support from four to 12 days. All patients were successfully weaned and discharged alive. In treating these patients, the authors were able to avoid V-A ECMO or central right ventricular support. The authors concluded that the ProtekDuo® cannula was easy to insert, safe and effective and is the preferred temporary mechanical support device for patients with isolated RV primary graft dysfunction after heart transplant [36].

4.1.2 ProtekDuo® for biventricular failure

Biventricular shock is characterized by elevated CVP (>14 mmHg), normal or elevated PCWP (>18 mmHg) and hypotension, along with reduced LV function. At least 40% of patients diagnosed with LV-dominant CS, in fact have biventricular failure [5].

The use of temporary [38] and durable [39, 40] LVADs has continued to increase over the last decade. Acute RV failure after LVAD implantation is reported to occur in up to 40% of cases [26, 41, 42, 43, 44]. Multiple causes, either alone or in combination, including unmasking of chronic RV dysfunction once RV preload increases, distortion of RV geometry due to bowing of the intraventricular septum toward the LV due to mechanical LV unloading, ventricular dysrhythmias, and embolic phenomenon to the coronary or pulmonary circulation are thought to precipitate RV failure [45]. Patients with LVADs who develop additional acute RV failure and require biventricular support have a high mortality [26].

Patients with shock in the setting of biventricular failure refractory to medical management are usually supported with V-A ECMO. However, if an LVAD is present, then the addition of isolated RV support can provide adequate cardiovascular support while avoiding potential challenges imposed by V-A ECMO including retrograde flow with increased LV afterload, complications of arterial access including extremity ischemia, and low transpulmonary flow [36]. The ProtekDuo® cannula may offer additional benefits including non-surgical, single-site access in the upper body, which may allow for earlier extubation and/or mobilization.

4.1.2.1 ProtekDuo® with temporary LVADs

A number of authors have presented cases of the ProtekDuo® cannula used in combination with an Impella temporary percutaneous LVAD for biventricular support. Our group has reported our experience with the combination of devices, which we describe using the novel portmanteau “PROpella” [46].

The Impella CP is a percutaneous LVAD capable of delivering up to 3.5 liters per minute of flow. Patel and colleagues reported a case of a patient with biventricular failure who was supported with the combination of a ProtekDuo® and Impella CP inserted via the axillary artery thus allowing the patient to be awake and ambulate. Chivasso et al. reported a case of a 38-year-old patient who underwent emergent coronary artery bypass grafting that was complicated by electrical storm initially supported with V-A ECMO, but was later converted to biventricular support with ProtekDuo® cannula and Impella CP. See Figure 2.

Figure 2.

PROpella approach with ProtekDuo® and oxygenator in RVAD/V-P ECMO position and Impella CP in LVAD position. Modified from: Maybauer MO et al. The ProtekDuo® in percutaneous peripheral venopulmonary-arterial ECMO and PROpella configuration for cardiogenic shock with biventricular failure. Ann Card Anaesth. In Press. With kind permission from Ann Card Anaesth.

The Impella 5.0 (no longer available) and the newer Impella 5.5 are surgically placed and capable of delivering up to 5.5 liters per minute of flow. Routh and co-authors reported a case of a 61-year old man with inotrope-dependent nonischemic cardiomyopathy who developed acute cardiogenic shock initially treated with Impella 5.5. The patient subsequently developed acute RV failure and a ProtekDuo® cannula was placed, allowing for biventricular support [45]. Ramamurthi et al. reported a case series of six patients who underwent carotid placement of an Impella 5.5 for left ventricular support. One patient in the series, a 49-year-old woman, required placement of a ProtekDuo® cannula for concomitant RV failure. Care was later withdrawn due to inability to wean from mechanical support [47]. Kataria and colleagues described three cases of successful use of ProtekDuo® for acute right heart failure in patients with Impella 5.5 placed for heart failure-related cardiogenic shock, though specific outcomes of these patients were not discussed [48]. See Figure 3.

Figure 3.

PROpella approach with ProtekDuo® and oxygenator in RVAD/V-P ECMO position and Impella 5.5 in LVAD position. Modified from: Maybauer MO et al. The ProtekDuo® in percutaneous peripheral venopulmonary-arterial ECMO and PROpella configuration for cardiogenic shock with biventricular failure. Ann Card Anaesth. In Press. With kind permission from Ann Card Anaesth.

4.1.2.2 ProtekDuo® with durable LVADs

A number of authors have presented larger case series and retrospective cohort studies of patients supported with ProtekDuo® after implantation of durable LVAD.

Ravichandran and co-authors published a case series of 17 patients with acute RV failure supported with ProtekDuo® cannula. In their series, acute RV failure occurred mostly following implantation of an LVAD: 12 patients after durable LVAD implantation and one patient after temporary percutaneous LVAD implantation. The remaining four patients had acute RV failure due to other causes. Device-related complications including vessel injury occurred in one patient and bleeding from the cannula site in two patients. The mean duration of RVAD support with ProtekDuo® was 10.5 ± 6.5 days and six patients required conversion to surgical or durable RVAD for extended support [26].

In a retrospective study of 11 patients with acute RV failure at the time of durable LVAD implantation, Schmack et al. reported a mean duration of support with ProtekDuo® of 16.8 ± 9.5 days. The authors reported no device-related complications. In the series, 91% of patients survived to device weaning. The cohort had a 30-day survival of 73% and 180-day survival of 64% [35].

Salna and colleagues performed a retrospective study of 27 patients who underwent durable LVAD implantation and subsequently developed acute RV failure. All patients were placed on RVAD support using a ProtekDuo® cannula and were supported a median duration of 11 days. The median reported dose of required vasopressor and inotrope was significantly lower at 6-hours post-insertion. The authors reported an 85% survival to both discharge and at 30-days. Complications related to the ProtekDuo® cannula were few with cannula migration occurring in two patients and device-related thrombosis occurring in one patient. A total of three patients required conversion to surgical RVAD for prolonged support [23].

Lim and colleagues conducted a retrospective analysis of 11 patients with acute RV failure due to various etiologies. Most patients in the series had RV failure after LVAD: seven after durable LVAD and two with end-stage heart failure cardiogenic shock after temporary percutaneous LVAD implantation. The remaining two patients had post-heart transplant graft dysfunction. The authors reported a significant reduction in right heart filling pressures, but no significant difference in vasopressor and inotrope dose at 3-hours post-cannulation. The patients in this cohort required RVAD support with ProtekDuo® for a median duration of 10 days and had a 90-day survival of 64%. Device-related complications were not reported in this study [33].

4.2 ProtekDuo® as a left ventricular assist device

While uncommon, the ProtekDuo® cannula has also been used as an LVAD. Rao and colleagues described the use of a combined 21-Fr peripheral venous drainage cannula with a transapical 31-Fr ProtekDuo® cannula inserted via mini-thoracotomy for biventricular support in a 44-year-old with non-ischemic cardiomyopathy in cardiogenic shock [49]. Alaeddine and co-authors described the transapical placement of a 29-Fr ProtekDuo® cannula in a 10-year-old for temporary mechanical support prior to implantation of a total artificial heart [50]. Goodwin et al. described the use of a transapical 31-Fr ProtekDuo® cannula inserted via mini-thoracotomy for temporary left heart support in a 51-year-old patient with ischemic cardiomyopathy and cardiogenic shock, who was not expected to tolerate peripheral V-A ECMO due to significant aortic valve pathology [51].

4.3 ProtekDuo® as a biventricular assist device

Khalpey and colleagues first described the use of dual ProtekDuo® cannulas for biventricular support in three patients. The first patient was a 22-year-old with non-ischemic cardiomyopathy complicated by acute decompensated biventricular heart failure. The second patient was a 46-year-old with ischemic cardiomyopathy who underwent coronary artery stent placement with Impella support complicated by electrical storm. In both patients, a 29-Fr ProtekDuo® was modified and placed transapically into the left ventricle through a mini-thoracotomy followed by standard placement of a 29-Fr ProtekDuo® cannula in the pulmonary artery. This configuration allowed for extubation and ambulation of both patients until placement of total artificial heart while awaiting heart transplant in the first patient and recovery in the second patient. The third patient was a 63-year-old with anterior STEMI complicated by cardiogenic shock despite intra-aortic balloon counterpulsation. He underwent transapical placement of a ProtekDuo® cannula for LV support but had electrical storm and required placement of a ProtekDuo® cannula for RV support. The ProtekDuo® RVAD was weaned, but his family later consented to withdraw life support. The authors concluded that use of dual ProtekDuo® cannulas for biventricular support was a safe and effective method of establishing biventricular assist device (Bi-VAD) placement allowing avoidance of sternotomy, cardiopulmonary bypass with its associated complications, and peripheral ECMO while allowing for early extubation and ambulation [52].

5. The ProtekDuo® for extracorporeal membrane oxygenation

Conventional management for ARDS includes low tidal volume ventilation, neuromuscular blockage, and prone positioning. Pulmonary vasodilators are often used for temporary improvement of oxygenation and to bridge a patient to ECMO. Veno-venous (V-V) ECMO can be used in refractory hypoxemia and/or hypercapnia, or ventilator induced lung injury, and may typically be provided by single lumen dual site cannulation (femoro-internal jugular) or dual lumen single site cannulation (DLSC), typically via internal jugular vein approach. In the venous system, flow is dependent on the capacitance of the vessels, tricuspid competence, as well as systolic and diastolic function of both ventricles. In addition, pulmonary artery pressure, RV afterload, and total systemic cardiac output play an important role. V-V ECMO may display varying degrees of recirculation of blood depending on the flow rate, proximity of the inflow to outflow cannula(s), cannula location, and cannula size [53].

Impaired RV function occurs frequently in patients with ARDS [54, 55] and is associated with increased mortality [55, 56]. During the COVID-19 pandemic, clinicians observed a particularly high incidence of acute and subacute RV failure [57] with dramatic increases in pulmonary vascular resistance due to the combined effects of hypoxia, hypercapnia, lung injury, and attempted sedation weaning [58]. Additionally, hypercoagulation associated with COVID-19 frequently led to both macro- and micro-pulmonary emboli, which further increased pulmonary pressures, RV dilation, and failure of systolic pump function resulting in hypotension and need for inotropes and vasopressors [59]. Understanding RV biomechanics and, in particular, the relationship between the RV and PA is key to identifying different phases of RV dysfunction leading to RV failure, hypotension and death. ECMO cannulas bypassing the RV are now being increasingly utilized for COVID-19 ARDS to counterbalance RV dysfunction.

The ProtekDuo® dual lumen cannula is similar to other dual lumen cannulas and may be used for V-V ECMO in cases of ARDS. If significant RV dysfunction or failure is present and resulting in the requirement of inotropes and vasopressors to counterbalance hypotension, the cannula can be used for combined V-V ECMO and RV support, a configuration commonly referred to as V-P ECMO or oxyRVAD [60]. See Figure 1c. The main difference between the ProtekDuo® and other dual lumen cannulas is that the tip of the ProtekDuo® terminates in the main PA and not in the inferior vena cava as it is the case with other dual lumen cannulas. The ProtekDuo®‘s V-P ECMO default position may be a particularly beneficial feature in ARDS, not only because it is able to bypass the RV, but because the area of venous blood drainage from the RA and area of oxygenated blood return in the main PA are separated by two cardiac valves (tricuspid and pulmonic valve) thus preventing recirculation, a phenomenon commonly seen with other dual lumen ECMO cannulas. Considering the length and diameter of the cannula, an average flow of 4.5 LPM may be achieved, which usually provides adequate blood flow and oxygenation [53].

The COVID 19 pandemic resulted in much longer ECMO run times than ECMO teams were accustomed to, the incidence of RV failure and hypotension increased because of prolonged ARDS with the development of some degree of pulmonary hypertension and the ProtekDuo® was used more frequently in V-P ECMO configuration, even as primary device to initiate ECMO. Several interesting configurations have been developed during the COVID-19 pandemic, mostly due to clinical desperation and medical necessity, as described below.

5.1 ProtekDuo® in V-P ECMO configuration

In a recent systematic review on the utilization of the Protek Duo cannula for V-P ECMO (Figure 1c) in ARDS secondary to COVID-19 infection, our group identified five suitable articles including 194 patients who underwent ProtekDuo® implantation in combination with an oxygenator. The ProtekDuo® demonstrated survival rates of 59–89% throughout the studies with a significant survival benefit [61].

Mustafa et al. presented their experience with the ProtekDuo® in V-P ECMO configuration for patients with ARDS secondary to COVID-19. The authors presented a case series of 40 patients with an average duration of mechanical ventilation of 13 days. They reported an 80 percent (32 patients) rate of successful ECMO weaning with a 73% (29 patients) survival rate [62].

Cain and colleagues compared 39 patients in a V-P ECMO group of 18 patients and an invasive mechanical ventilation (IMV) group of 21 patients. The authors displayed a significant reduction of in-hospital (52.4 vs. 11.1%, P = 0.0008) and 30-day mortality rates (42.9 vs. 5.6%, P = 0,011) in favor of the V-P ECMO group without complications related to the device. While the IMV group presented with 15 cases of acute kidney injury (AKI, 71.4%, P < 0.001), the V-P ECMO group did not display a single patient with AKI [63].

Saeed et al. compared the cannulation approach in a retrospective multicenter trial of 435 adult patients. They compared dual-site vs. single-site cannulation. For dual site they used the two most common approaches, femoral vein to femoral vein and femoral vein to internal jugular vein access. For the single site approach, they used either the Protek Duo, Crescent, or Avalon cannulas through an internal jugular vein. Out of 435 patients, 99 (23%) received the ProtekDuo®, 89 (20%) had single site inferior vena cava (IVC) approach, and 247 (57%) had dual site approach. The authors demonstrated that the 90-day in hospital mortality for the entire cohort was 55%. The unadjusted 90-day in hospital mortality was 60% for dual site, 41% for ProtekDuo®, and 61% IVC approach. The 90-day in-hospital mortality was significantly lower in the ProtekDuo® group (p = 0.029), but not significantly different between single site IVC compared to dual site approach (p = 0.86). However, patients who were cannulated with the ProtekDuo® had longer duration of the ECMO runs compared to the other approaches but had shorter periods of mechanical ventilation and were more commonly discharged home [64].

A cohort of 54 patients was investigated by Smith and colleagues, comparing the ProtekDuo® with V-V ECMO for a one-year period during the pandemic. Thirty percent of their patients had V-V and 70% had V-P ECMO with a median time of 7 days from admission to ECMO cannulation. The authors reported a median ECMO support time of 30.5 days (V-V ECMO 35.0 days vs. V-P ECMO 26.0 days). Their mortality with V-P ECMO was 39.5%, with a 50.0% mortality for V-V ECMO with a total in-hospital mortality of 42.6%. The mortality after 120 days for V-V ECMO was 60.8% and only 40% for V-P ECMO, with a total cumulative mortality of 45.7%. This group concluded that ECMO support for ARDS secondary to COVID-19 is beneficial and that V-P ECMO support displayed consistent advantages in survival compared to V-V ECMO [65].

In addition to these studies, an interesting case was reported by Gianni et al., that may be very useful in patients with pulmonary embolism. In this patient, an inferior vena cava filter was positioned to prevent embolization from a left femoral deep venous thrombosis. The patient also had a large lesion of the tracheal posterior wall. Tracheal stenting required V-V ECMO support to safely perform the bronchoscopic procedure. Due to the presence of the inferior vena cava filter, the patient was cannulated with the ProtekDuo® cannula, since it does not interfere with the IVC, while dual site or double lumen cannulas typically end in the IVC. The patient could be weaned off ECMO after the procedure and the tracheal stent was removed after 40 days with full recovery, expanding the potential indications for the ProtekDuo® cannula [66].

5.2 Protek duo in V-VP ECMO configuration

This new technique and configuration for the ProtekDuo® was developed by Maybauer during the COVID-19 pandemic when treating a patient with persistent, severe hypoxia while on V-P ECMO with blood flows of 4.5 to 5 LPM. In an attempt to achieve more blood flow, a 25-Fr femoral multistage cannula was inserted for venous drainage. The post-pump tubing was spliced with a 3/8-in Y-connector to distribute the blood flow to both lumina of the ProtekDuo®, which resulted in return of oxygenated blood to the right atrium and main pulmonary artery in a configuration that could be best described as V-VP ECMO [67] (See Figure 4).

Figure 4.

Chest X-ray of ProtekDuo® in V-P ECMO position with additional 25Fr drainage cannula with tip in right atrial/inferior vena cava junction through a femoral vein. Drainage through the femoral cannula and return through both lumens of the ProtekDuo® using a Y-piece after the oxygenator. Modified from: Maybauer MO et al. The ProtekDuo® as double lumen return cannula in V-VP ECMO configuration: A first-in-man method description. Ann Card Anaesth. 2022;25(2):217-9. With kind permission from Ann Card Anaesth.

Returning blood flow improved to 7 LPM resulting in resolution of hypoxia and maintenance of SpO2 > 90%, which finally allowed for the use of ventilator “rest settings” (Inspiratory Plateau Pressure < 25 to <30 cmH₂O, Respiration Rate 4-15 breaths per minute, PEEP >10 cmH₂O, FiO2 0.3 to 0.5). Using ultrasonic flow probes, blood flows to both ProtekDuo® lumina were measured and monitored independently. Due to length and diameter of the cannula, about 60% of flow returned into the RA and about 40% of flow returned into the pulmonary artery. Still, about 3 LPM bypassed the RV, which was sufficient to protect the RV in this patient. Frequently repeated transthoracic echocardiograms confirmed adequate decompression of the RV. The patient was able to separate from V-P-ECMO after 44 days with 29 days on the new configuration. The patient did not have any complications associated with this new configuration [67].

Most recently, the group of Maybauer presented a case series of nine patients, using the ProtekDuo® in V-P and V-VP ECMO configuration [19]. The authors could show that in contrast to the above-mentioned studies where V-P ECMO was the initial configuration, this study showed that V-P or V-VP ECMO configuration was established weeks after the onset of ARDS with initial dual site V-V ECMO. This selected group of patients still displayed good outcomes with a survival rate of 67%, indicating the Protek Duo has been a game changer when used in patients with ARDS secondary to COVID-19 [68].

5.3 Protek duo in VP-A ECMO configuration

Budd et al., described the “central” VP-A ECMO configuration for a patient who was to receive a bilateral, sequential native pneumonectomy and donor lung transplantation after having V-P ECMO in situ. Following a sternotomy, they inserted an 18-Fr cannula (Edwards Lifesciences, Irvine, CA) into the ascending aorta. Thereafter, blood was drained through both lumens of the ProtekDuo® cannula and oxygenated blood was returned into the aorta as intraoperative central V-A ECMO configuration or more precisely called central VP-A configuration. After initiation, good decompression of the heart was achieved, which allowed for completion of pneumonectomy and donor lung transplantation. Before chest closure, the arterial cannula was removed and V-P ECMO was reinstated through the ProtekDuo® [69]. Similar techniques have been described by Settepani et al. for orthotopic heart transplantation [70] and by Sinha et al. in a combined heart and lung transplantation [71]. Either ECMO or cardiopulmonary bypass was used as pump in the above-mentioned circumstances of short intraoperative support.

Most recently, Maybauer et al. described a case with a patient who had a non ST elevation myocardial infarction (NSTEMI) and suffered a cardiac arrest on the catheter laboratory table. After return of spontaneous circulation (ROSC) was achieved, the patient developed biventricular failure with severe refractory hypotension and an Impella CP was placed. The patient remained in shock, requiring high doses of inotropes and vasopressors. A follow up echocardiogram demonstrated ongoing biventricular failure. A 29 Fr ProtekDuo® cannula was placed as RVAD with ECMO circuit in V-P configuration. With the Impella CP already in situ, a PROpella configuration was created (Figure 2), and the patient was stabilized. After a few hours, the patient displayed signs of limb ischemia due to occlusion of the femoral artery by the Impella CP. A thrombectomy and left calf fasciotomy was necessary and the Impella CP had to be removed. Because the patient developed pulmonary edema after Impella CP removal, a 17 French arterial and 5 Fr distal perfusion cannula were placed in the contralateral proximal femoral artery. The circuit tubing connected to the ProtekDuo® was clamped, cut, and wet connected to a new ECMO circuit using a Y-piece and used for dual-lumen venous drainage from both the RA and main PA. Oxygenated blood was returned through the 17-Fr arterial cannula, creating a “peripheral” VP-A ECMO configuration (Figure 5). This peripheral configuration however could be used for about 24 h without complications in comparison with the use of central VP-A configuration on CPB [46].

Figure 5.

ProtekDuo® in VP-A ECMO position for double lumen drainage from right atrium and pulmonary artery and return flow into femoral artery through 17 Fr cannula and 5 Fr distal perfusion cannula. Modified from: Maybauer MO et al. The ProtekDuo® in percutaneous peripheral venopulmonary-arterial ECMO and PROpella configuration for cardiogenic shock with biventricular failure. Ann Card Anaesth. In Press. With kind permission from Ann Card Anaesth.

In a similar configuration, Kumar and colleagues described left ventricular unloading utilizing pulmonary artery drainage in cardiorespiratory failure due to COVID-19 infection. They described ProtekDuo® insertion for LV venting who was first on V-V ECMO and then converted to V-A and developed LV distention [72].

6. Conclusion

CS is a serious and life threating problem with high mortality rates. In case of acute ventricular failure, the main goal is to quickly implement measures to allow for ventricular recovery, by offloading volume and pressure, while maintaining adequate end-organ perfusion. When conventional treatment options fail, acute mechanical circulatory support is indicated. The ProtekDuo in RVAD configuration has the particular advantage over other single-site cannula-based temporary percutaneous RVADs because it is placed in the upper body versus the groin, thus allowing the patient to freely use the lower extremities in case of mobilization. Further, the ProtekDuo is compatible with a variety of blood pumps and may be used with a membrane oxygenator (ECMO) in case of concomitant respiratory failure, which is not an available option with other single-site, temporary percutaneous RVADs. When used in ECMO configuration, the ProtekDuo® may be used for V-P, V-VP, and VP-A ECMO as well as in PROpella configuration. Each option has specific benefits for patients requiring individual support for respiratory, right heart, left heart or biventricular failure. In V-P position, a mean blood flow of 4.5 LPM may be achieved but can be increased to 7 LPM in patients with V-VP configuration for ARDS. With increasing blood flow, increasing oxygenation may be achieved. Most literature on the ProtekDuo® in ARDS exists for COVID-19, where it has been shown to improve outcomes, reduce AKI and consecutively reduce the need for CRRT. The use of the ProtekDuo® for other ARDS etiologies has not yet been described. Cardiocirculatory support may be provided in PROpella or VP-A configuration. All options have been used and shown to be feasible. With a limited number of cases, safety cannot be guaranteed but may be likely.

Acknowledgments

The authors thank the Editor of Annals of Cardiac Anesthesia, Professor Mukul Chandra Kapoor, for kind permission to use figures from our previous publications in his journal, and LivaNova for covering the open access publication costs.

Conflict of interest

LivaNova covered the cost of publication. The authors have not received direct support.