Selection of Patients with Aortic Aneurysms for Open Surgical or Endovascular Repair



Selection of Patients with Aortic Aneurysms for Open Surgical or Endovascular Repair



K. Brigitte, Smith and K. Craig Kent


An abdominal aortic aneurysm (AAA) is lethal; if associated with rupture, it carries an 85% risk of death. In patients with AAA, early diagnosis and prophylactic surgical intervention are essential to prevent rupture.


Open AAA repair was originally pioneered in the 1950s, and surgical techniques have continuously improved since then. Endovascular aneurysm repair (EVAR) was pioneered in the 1990s and also has evolved significantly since then. Endovascular grafts were first FDA approved in the United States in 1999, and by 2005, the incidence of endovascular repair overtook that of open repair. Currently, more than 70% of AAA repairs are performed using endovascular techniques. However, uncertainty remains regarding long-term outcomes, cost, and quality of life in patients receiving EVAR. Despite advances in EVAR technology, a significant number of patients still have anatomic contraindications. Thus, which patients benefit from open repair and in which patients EVAR is the preferred technique, remains controversial.



Open Repair of Abdominal Aortic Aneurysm


Improvements in patient selection, preoperative preparation, anesthesia, surgical technique, and postoperative care have made open AAA repair a safe surgical option for most patients.


Reported morbidity following open AAA repair varies widely and increases with age. Early postoperative complications are related to underlying comorbidities and include respiratory (8%–16%), major cardiac (3%–8%), renal (2%–10%), visceral ischemic (1%–3%), and sexual (erectile dysfunction and retrograde ejaculation) (≤85%) complications. Late graft-related complications are uncommon but can be associated with mortality and include anastomotic pseudoaneurysm (1%–3% proximal, 8%–9% distal), graft infection (0.3%–1.3%), aortoenteric fistula (0.3%–1.6%), limb thrombosis (1.6%–5.3%) and aneurysmal expansion of the residual aorta (5%). Nonvascular late complications also occur including ventral hernia, small bowel obstruction, and ischemic colitis. Moreover, it has recently been recognized that the incidence of these complications is relatively high. Mortality for open repair has remained relatively stable since the 1990s, with 30-day mortalities of less than 3% at centers of excellence and 4% to 6% when large data sets are queried.



Endovascular Aneurysm Repair


Since the turn of the century, EVAR devices have continued to improve. This poses a significant problem when attempting to assess the long-term outcomes of technically laden surgical interventions. Even the most recently reported long-term studies of EVAR evaluate grafts that are a decade old. The indications for EVAR have also evolved and have become less constrained. Initially, grafts were implanted only in patients with infrarenal necks less than 28 mm in diameter and greater than 15 mm in length as well as through large and nondiseased iliac vessels. However, currently grafts are placed in patients with short and large-diameter necks and also in patients with significant iliac disease. Thus, from an anatomic standpoint, the scope of patients for whom EVAR is an option has varied widely.


The improved early outcomes of EVAR have made it a desirable option in treating AAAs. EVAR does not routinely require general anesthesia or postoperative ICU admission. The surgical exposure is limited to the femoral arteries and can be totally percutaneous. Laparotomy and aortic cross clamping are avoided, with the attendant physiologic stress, blood loss, and fluid shifts. Hospital stays are shortened compared to those for open repair, and time to full recovery following EVAR is significantly shortened. Thirty-day mortalities following EVAR have improved over time, and recently reported mortalities from both prospective trials and larger data sets are less than 1%. Although there is significant early advantage to EVAR, there are a plethora of late complications including endoleak, graft migration, limb occlusion, and rupture, all of which mandate lifelong monitoring of these patients.



Open Versus Endovascular Aneurysm Repair: The Data


Over the years, hundreds of studies have been published reporting outcomes of open and endovascular aneurysm repair. However, only recently several long-term randomized, comparative trials have been reported. Before the publication of these studies, there was significant concern that late complications of EVAR would lead to substantial late mortality and perhaps long-term outcomes that are unfavorable compared to those of open repair. A summary of the findings of the most significant of these recent reports follows and is shown in Table 1.



TABLE 1


Sentinel Trials of Open Surgical Repair versus Endovascular Repair to Treat Large Abdominal Aortic Aneurysm∗
































































Study Year N Total Years of Follow-Up 30-DAY MORTALITY (%) SURVIVAL (%) %REINTERVENTION RATE (%)
EVAR Open EVAR Open EVAR Open
EVAR-1 1999–2003 1,252 8 1.8 4.3 54 54 20 6
DREAM 2000–2003 351 6 1.2 4.6 69 70 30 18
OVER 2002–2008 881 2 0.5 3.0 93 90 14 13
Schermerhorn
et al.		 2001–2004 45,660 4 1.2 4.8 65 65 13 11


image


DREAM, Dutch Randomized Endovascular Aneurysm Management trial; EVAR, endovascular aneurysm repair; EVAR-1, Endovascular versus Open Repair of Abdominal Aortic Aneurysm trail; N, number of patients randomized; OVER, Open Versus Endovascular Repair trial.


∗Numbers presented are estimates from figures.



Endovascular versus Open Repair of Abdominal Aortic Aneurysm Trial


The Endovascular versus Open Repair of Abdominal Aortic Aneurysm (EVAR-1) trial was a randomized clinical trial that included patients from 37 centers in the United Kingdom. Between 1999 and 2004, 1252 patients with AAAs that were 5.5 cm or larger and suitable for either repair technique were randomly assigned to undergo either open repair (n = 626) or EVAR (n = 626). The median follow-up was 6.0 years. There was an early benefit in the EVAR group in 30-day mortality (1.8% compared to 4.3% in the open repair group). However, by the end of the 8-year follow-up period, there was no significant difference between the two groups in overall mortality (7.5 deaths per 100 person-years in the EVAR group and 7.7 deaths per 100 person-years in the open repair group [p = .72]). The aneurysm-related mortality was also not significantly different between the two groups at 1.0 death per 100 person-years in the EVAR group and 1.2 deaths per 100 person-years in the open repair group (p = .73).


The rates of graft-related complications and reinterventions were higher in the EVAR group than in the open repair group by a factor of three to four. Out to 8 years of follow-up, the percentage of patients surviving without a complication was 48% in the EVAR group and 85% in the open repair group, and the percentage of patients surviving without a reintervention was 72% and 90%, respectively. Complications and reintervention rates might have been underestimated in the open repair cohort because data were not collected for abdominal wall hernia, small bowel obstruction, or other complications specifically related to open repair. The average cost of the primary aneurysm repair was $19,698 for EVAR and $17,917 for open repair. During 8 years of follow-up, the total average cost of aneurysm-related procedures was $4,568 more for EVAR than for open repair.


The authors concluded that compared with open repair, EVAR offers an early survival advantage. However, no long-term differences were seen between the two in total or aneurysm-related mortality. EVAR was also found to be associated with an increased rate of complication and reintervention and was more costly.

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Aug 25, 2016 | Posted by in CARDIOLOGY | Comments Off on Selection of Patients with Aortic Aneurysms for Open Surgical or Endovascular Repair

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