Treatment of Ruptured Abdominal Aortic Aneurysms

Objective To explore the diagnosis and treatment of ruptured abdominal aortic aneurysm (RAAA). Methods Between January 1996 and December 2009, 14 patients with RAAA were treated. There were 13 males and 1 female with an average age of 65 years (range, 50-82 years). The main clinical manifestations were abdominal pain and/or back pain. Ten cases had low blood pressure or shock. All cases were accurately diagnosed with CT, Doppler ultrasonography, or operation. The aneurysm diameter was from 4.5 cm to 8.0 cm. Eleven cases were treated by conventional operation, 1 by endovascular aortic repair, 1 by conservative treatment, and 1 case died after admission treatment. Results Perioperative death occurred in 6 cases (mortality rate was 50%) in 12 surgical patients. One case died after conservative treatment. The overall mortality rate was 57.14% (8/14). The causes of death included circulatory failure in 2 cases and multiple organ failure in 4 cases. The other 6 cases were cured. The postoperative hospitalization days were 12 to 34 days (14 days on average). A total of 4 cases were followed up 11 to 40 months without related complication. Conclusion Surgical treatment is still a main method to treat RAAA. Early diagnosis, appropriate resuscitation, and urgent surgical repair are crucial to reduce the mortality rate of RAAA.

aged between 65-85 years in developed countries (Sakalihasan et al., 2005).This percentage is probably even higher due to underestimation of AAA related mortality, since AAAs generally exist without symptoms (Acosta et al., 2006).In patients with an identified AAA and abdominal and/or back pain in combination with pain at palpation of the aneurysm (a so called symptomatic AAA), pending rupture of the AAA is assumed.However, evidence for a symptomatic AAA representing pending rupture is lacking (Scott et al., 2005).When rupture occurs, the mortality rate is as high as 80% (Semmens et al., 2000;Veith et al., 2003;Gorham et al., 2004).Forty percent of the patients with a ruptured AAA do not reach the hospital alive (Semmens et al., 2000) and in patients reaching the hospital and undergoing surgery, the mortality rate is approximately 50% (Sayers et al., 1997).Despite progression in surgical techniques, anaesthetical management, vascular prostheses and perioperative care, there is only a gradual decline in operative mortality rate over the past decades (Heller et al., 2000;Bown et al., 2002).In 1991, a new minimally invasive technique was described by Parodi et al. to treat AAA, endovascular aneurysm repair (EVAR) (Parodi et al., 1991).In the elective setting, EVAR showed an absolute and relative mortality risk reduction of approximately 3 and 75%, respectively (Prinssen et al., 2004;EVAR-trial-participants 2005).In the acute setting, emergency EVAR (eEVAR) is a strategy that might allow for improvement in above mentioned poor prognosis.Since 1994 an increasing amount of publications of eEVAR to treat acute AAAs is published.Currently, eEVAR has become an accepted treatment option which is increasingly being performed to treat acute AAA.However, the potential reduction in peri-operative mortality of eEVAR compared to conventional open repair in patients with an acute AAA is still open to debate. in this chapter, we will discuss the role of endovascular AAA repair in patients with a ruptured AAA.inhibition of sympathetic arterial tone.The hypotension and subsequent inadequate oxygenation might induce or accelerate cerebral en cardiac ischemia, resulting in a poor clinical prognosis.Furthermore, loss of abdominal muscle tone can occur during the induction of general anaesthesia which might cause free rupture of the retroperitoneal haematoma with related haemodynamical consequences (Lachat et al., 2002).During surgical exposure, blood loss is generally extensive (Sadat et al., 2008).Hypotension and subsequent inadequate oxygenation might induce or accelerate cerebral en cardiac ischemia, resulting in poor clinical prognosis.Furthermore, after removing the clamps, considerable ischemia-reperfusion injury of the lower extremities and the intra-abdominal organs might occur (Bown et al., 2003).

Minimally invasive endovascular ruptured AAA repair
In 1991, Parodi et al described a less invasive alternative to conventional 'open' aneurysm repair for the treatment of AAA, Endovascular Aneurysm Repair (EVAR) (Parodi et al., 1991).EVAR involves groin incisions in order to expose the femoral arteries.Using a catheter and guidewire a synthetic stentgraft is fed through the artery up to the AAA neck until positioned correctly just below the renal arteries and subsequently unfolded, excluding the aneurysm sac from blood flow and pressure.Control angiography is performed to assure correct placement of the endovascular stentgraft.Aorto-uni-iliac stentgrafts, reaching one of the common iliac arteries as well as bifurcated stentgrafts, reaching both iliac arteries are available.In case of aorto-uni-iliac stentgrafting, femoro-femoral bypass graft surgery has to be performed in order to restore blood flow to the contralateral leg.A controlateral endovascular occluder is used to stop retrograde bleeding up into the iliac artery into the aneurysm sac.Due to increasing expertise and continuous improvement of both stentgrafts and their delivery systems, increasing success rates and decreasing complications and reintervention rates are observed (Lovegrove et al., 2008).After several years of experience in EVAR for unruptured AAAs this technique has gradually extended its indication and is currently used to treat feasible patients with a ruptured AAA (Yusuf et al., 1994).However, the applicability for EVAR depends on several anatomical and logistic conditions.Anatomical suitability for EVAR is assessed on a preoperative CTA scan and evaluated for infrarenal aortic neck length, neck angulation and iliac and femoral access arteries that need to be large enough to accommodate the introducer system (Kapma et al., 2005).Approximately half of the ruptured AAAs is considered anatomically suitable for eEVAR according to the preoperative CTA scan (Hoornweg et al., 2007).However, logistic problems are often reported which frequently led to the exclusion of EVAR-suitable patients for undergoing endovascular repair (Yilmaz et al., 2002;Reichart et al., 2003;Kapma et al., 2005;Franks et al., 2006;Peppelenbosch et al., 2006;Visser et al., 2006;Acosta et al., 2007).Logistic criteria for EVAR in patients with a ruptured AAA are the instant availability of a CT-scanner, the 24/7 availability of an operating room that is adequately equipped to perform endovascular procedures as well as an endovascular trained staff.Financial burden is sometimes the availability of a large variety of 'off-theshelf' stent-grafts (Mehta et al., 2006).

Discussion
Theoretically, both the endovascular and the conventional open technique have benefits.During open repair the aorta is clamped short after the initiation of the procedure, ceasing the blood loss.During endovascular repair on the other hand, the ruptured aneurysm remains part of the circulation until the entire endograft is deployed and correctly positioned without major endoleak.Reported results of reduced early mortality after EVAR for the treatment of a ruptured AAA compared to open surgery seems conclusive (table 1).However, the currently available, mainly observational, studies are small and add considerable heterogeneity and methodological limitations (Yilmaz et al., 2002;Reichart et al., 2003;Resch et al., 2003;Lee et al., 2004;Alsac et al., 2005;Brandt et al., 2005;Castelli et al., 2005;Hechelhammer et al., 2005;Kapma et al., 2005;Larzon et al., 2005;Vaddineni et al., 2005;Arya et al., 2006;Coppi et al., 2006;Franks et al., 2006;Hinchliffe et al., 2006;Peppelenbosch et al., 2006;Visser et al., 2006;Acosta et al., 2007;Ockert et al., 2007).Heterogeneity is signified by the broad range in percentages of patients treated with EVAR (15-50%) and in percentage of haemodynamical unstable patients (33-73% in the eEVAR group).Even the definition of haemodynamical instability varied between the studies from a systolic blood pressure below 50 mmHg to 100 mmHg.Furthermore, the comparative studies reported so far are flawed by methodological inadequacies such as high potential of selection bias and lack of randomisation (Dillon et al., 2007).Selection bias is created by selecting patients for EVAR constituting a lower-risk category, presuming they need to be haemodynamically more stable for preoperative imaging and have a more favourable (EVAR-suitable) anatomic configuration.In a previous report, though not randomized, we eliminated selection bias due to inadequate patient matching by reporting a comparison of EVAR and open surgery in patients who all had the same preoperative imaging protocol, irrespective of haemodynamic condition, and who were all anatomically suitable for EVAR (Ten Bosch et al., 2010).This study showed a significant reduction in 30-day and 6-month mortality of EVAR compared to open ruptured AAA repair.However, a larger conducted prospective randomised trial such as the Amsterdam Acute Aneurysm Trial, which is currently performed in the Netherlands, is needed to identify possible benefits of EVAR over open surgery in patients with a ruptured AAA.The pilot study of Hinchliffe et al showed the possibility to recruit patients with a ruptured AAA to a randomised trial of open surgery and EVAR (Hinchliffe et al., 2006).However, a RCT might give ethical concerns, given the accumulation of superior results with EVAR based on the available observational studies.In addition, a RCT in an acute, severe condition like a ruptured AAA, appears difficult to perform (Hinchliffe et al., 2006).Furthermore, long term effects on outcome still need further investigation.In case randomised trials demonstrate a clinically relevant reduction in mortality and morbidity for endovascular repair, consequences for care organisation will be major.Treatment of ruptured AAAs has to be performed in hospitals that are able to guarantee permanent availability of endovascular trained staff, implicating regionalisation and centralisation of acute AAA care.

Conclusion
The minimally invasive endovascular procedure (EVAR) is theoretically likely to reduce early mortality in patients with a ruptured AAA.The majority of observational studies show a clear trend toward an improved short term effect of EVAR and a significant reduction in early mortality compared to conventional open surgery.Therefore, EVAR has become a generally accepted treatment option for ruptured AAAs.However, studies comparing EVAR with conventional open surgery have to be interpreted with caution due to the likelihood of methodological inadequacies such as selection bias, heterogeneity, and lack of randomisation.Can endovascular repair of the ruptured AAA be considered as the treatment option of first choice?This question has not been answered yet.Further research in terms of randomised controlled trials with adequate follow-up will be required in order to clarify the role of endovascular repair as treatment option for ruptured abdominal aortic aneurysms.
and therefore no longer significant.