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Endovascular AAA repair associated with better early survival, more late rupture vs. open repair
Compared with open repair, endovascular repair of abdominal aortic aneurysm was associated with a better survival rate in the first 3 years, but a higher rate of late rupture in Medicare beneficiaries, according to recent findings.
Researchers assessed perioperative and long-term survival, reinterventions and complications after endovascular aneurysm repair (EVAR) compared with open repair of abdominal aortic aneurysm (AAA). The study population comprised a propensity-matched cohort (n = 39,966 matched pairs) of Medicare beneficiaries who underwent AAA repair from 2001 to 2008 and were followed through 2009.
Overall perioperative mortality was 1.6% for EVAR vs. 5.2% for open repair (P < .001), Marc L. Schermerhorn, MD, from the department of surgery at Beth Israel Deaconess Medical Center, and colleagues reported.
From 2001 to 2008, perioperative mortality decreased by 0.8 percentage points among patients who underwent EVAR (P = .001) and by 0.6 percentage points among those who underwent open repair (P = .01).
The rate of conversion from endovascular to open repair declined from 2.2% in 2001 to 0.3% in 2008 (P < .001), Schermerhorn and colleagues wrote.
Survival benefit for EVAR
EVAR was associated with a lower rate of death compared with open repair at 30 days (HR = 0.32; 95% CI, 0.29-0.35) and the next 60 days (HR = 0.64; 95% CI, 0.58-0.71). The survival benefit for EVAR persisted for 3 years, after which the survival curves for the two strategies came together, according to the researchers. Overall survival rates were higher from 2005 to 2008 than from 2001 to 2004.
Because of the early survival advantage, survival at 4 years in the EVAR group was 12.4 days longer, on average, compared with the open-repair group (95% CI, 9-15.6; P < .001) and 8.2 days longer at 7 years (95% CI, 1.5-14.4; P = .02), according to the results.
At 8 years, aneurysm-related interventions were more common in the EVAR group compared with the open-repair group (18.8% vs. 3.7%; P < .001); this was true both for major interventions (2.3% vs. 0.8%; P < .001) and minor interventions (17.5% vs. 3.1%; P < .001). However, interventions for complications related to laparotomy were more common in the open-repair group (17.7% vs. 8.2%; P < .001), according to the researchers.
Rupture and EVAR
Aneurysm rupture was more common at 8 years in the EVAR group (5.4% vs. 1.4%; P < .001).
The rate of total reinterventions in the EVAR group at 2 years declined from 10.4% in 2001 to 9.1% in 2007. The researchers attributed this improvement to a decrease in minor reinterventions, especially coil embolization.
“Our analysis confirmed the findings of previous studies that have shown that perioperative mortality and rates of complications are lower with endovascular repair than with open repair of [AAA],” Schermerhorn and colleagues concluded. “Late rupture after endovascular repair is a concern and warrants further study.” – by Erik Swain
Disclosures: Schermerhorn reports receiving grants from Cook Medical, Gore and Medtronic and personal fees from Endologix. The other researchers report no relevant financial disclosures.
Perspective
Back to TopPeople who perform EVAR need to pay attention to this trial, because it uses a very large matched-cohort population of Medicare patients and confirms previous trial results with much longer follow-up. The DREAM and EVAR-1 trials also compared open vs. endovascular AAA repair and found a short-term survival advantage for endovascular repair, which was lost after 1 to 4 years (EVAR Trial Participants. Lancet. 2005;doi:10.1016/S0140-6736(05)66627-5 and Prinssen M, et al. N Engl J Med. 2004;doi:10.1056/NEJMoa042002). The in-hospital mortality for DREAM was 4.6% for open repair and 1.2% for EVAR (risk ratio = 3.9), whereas the in-hospital mortality for EVAR-1 was 6% for open repair and 1.6% for EVAR (risk ratio = 3.9). Neither trial was designed to show a long-term difference in mortality, creating a concern for the long-term benefit in real-world nonselected patients. The present study is very large, with almost 40,000 matched pairs of patients in a nonselected population without extensive exclusion criteria. It’s everybody over 67 years in Medicare who had an aneurysm repair in the United States from 2001 to 2008 with 8 years of follow up. It essentially looks at all-comers. This study noted a perioperative mortality of 1.6% with EVAR vs. 5.2% with open repair. The study also shows that we got better at both EVAR and open repairs, with lower mortality for both during the study period. The survival advantage of EVAR did diminish over time in this study, with similar survival in the two groups after 3 years. The early survival advantage of EVAR is estimated to persist through 7 years.
I was very concerned seeing the high mortality rate for open surgery in patients older than 85. A 12.7% mortality in this population raises the question as to whether or not those patients should have no repair or be referred to a high-volume center of excellence with better results.
The study also points out that EVAR is not a perfect solution to treating an aneurysm. This is evidenced by the aneurysm-related intervention rate of 18.8% for EVAR. In contrast, it was only 3.7% for open repair. The 8-year rupture risk for endovascular repair was also much higher than the risk for open surgery (5.4% vs. 1.4%). Clearly, we are not where we need to be with results for EVAR.
This study doesn’t help us further define who is best suited for endovascular repair and who is best suited for open repair. If you look at the instructions for use (IFU) for FDA-approved endovascular devices during this time, only 60% of the patients had anatomy treatable according to the IFU. The discussion notes that in 2010, 78% of AAA repairs in Medicare patients are EVAR, so clearly many are done outside of an IFU, which may affect the risk for reintervention and rupture. This supports a study which found only 42% of 10,288 patients treated met the device IFU (Schanzer A, et al. Circulation. 2011;doi:10.1161/CIRCULATIONAHA.110.014902).
The study provides some important points to discuss with patients when offering a minimally invasive aneurysm repair. With EVAR through 7 years, they have a survival advantage, but it comes at the cost of a 1-in-5 chance of reintervention, and a 1-in-20 chance that the aneurysm may still rupture. Most patients have a difficult time grasping late risk, but clearly understand the difference between chances of dying at 30 days of 1.6% vs 5.2%. This early risk difference clearly has contributed to the increased utilization of EVAR in the US to almost 80% of patients.