National outcomes for the treatment of ruptured abdominal aortic aneurysm: comparison of open versus endovascular repairs

Abstract

Objectives: Endovascular repair (EVAR) of ruptured abdominal aortic aneurysms (rAAA) has been shown to acutely decrease procedural mortality compared to open aortic repair (OAR). However, little is known about the effect of choice of procedure; EVAR vs OAR, or the impact of physician and institution volume on long-term survival and outcome.

Methods: Patients hospitalized with rAAA who underwent either OAR or EVAR, were derived from the Medicare inpatient dataset (1995-2004) using ICD9 codes. We evaluated long-term survival after OAR and EVAR in the entire fee-for-service Medicare population, and then in patients matched by propensity score to create two similar cohorts for comparison with Kaplan-Meier analysis. Annual surgeon and hospital volumes of EVAR (elective and ruptured), OAR (elective and ruptured), and rAAA (EVAR and OAR) were divided into quintiles to determine if increasing volumes correlate with decreasing mortality. Predictors of survival were determined by Cox modeling.

Results: A total of 43,033 Medicare beneficiaries had rAAA repair: 41,969 had OAR and 1,064 had EVAR. The proportions of patients with diabetes, hypertension, cardiovascular, cerebrovascular, renal disease, hyperlipidemia, and cancer were statistically higher in the EVAR than in the OAR group, whereas lower extremity vascular disease was higher in the OAR group. The initial evaluation of EVAR vs OAR, prior to propensity matching, showed no statistical advantage in EVAR-survival after 90 days. The survival analysis of patients matched by propensity score showed a benefit of EVAR over OAR that persisted throughout the 4 years of follow-up (P = .0042). Perioperative and long-term survival after rAAA repair correlated with increasing annual surgeon and hospital volume in OAR and EVAR and also with rAAA experience. EVAR repair had a protective effect (HR = 0.857, P = .0061) on long-term survival controlling for comorbidities, demographics, and hospital and surgeon volume.

Conclusion: When EVAR and OAR patients are compared using a reliable statistical technique such as propensity analysis, the perioperative survival advantage of rAAA repaired endovascularly is maintained over the long term. Institutional experience with rAAA is critical for survival after either OAR or EVAR.

Fig 1

Percent of patients with ruptured aortic abdominal aneurysms repaired endovascularly (A), percent of surgeons using endovascular procedures for ruptured aortic abdominal aneurysm repair (B), and percent of hospitals using endovascular repair for ruptured aortic abdominal aneurysm (C) from 2001-2004. P values of trends shown in the parenthesis.

Fig 2

Kaplan-Meier analysis of survival of patients treated with endovascular (EVAR) and open (OAR) repair of ruptured aortic abdominal aneurysm. Cases were matched by patients baseline demographic (age, gender and race), comorbidities, annual hospital and surgeon volume and year of surgery using propensity score analysis.

Fig 3

Thirty-day mortality after ruptured aortic abdominal aneurysm surgery in relation to annual surgeon volume of aortic abdominal aneurysm repair by quintiles: A, open (ruptured and elective), B, endovascular (ruptured and elective), or C, ruptured (open and endovascular). *P <.05 for volume quintiles vs the first quintile.

Fig 4

Kaplan-Meier survival analysis after ruptured aortic abdominal aneurysm surgery by surgeon volume. A - survival after open repair of ruptured abdominal aortic aneurysm in relation to annual surgeon volume of open aortic abdominal aneurysm repair (ruptured and elective) by quintiles. B - survival after endovascular repair of ruptured abdominal aortic aneurysm in relation to annual performing surgeon volume of endovascular aortic abdominal aneurysm repair (ruptured and elective) by quintiles. C - survival after repair of ruptured abdominal aortic aneurysm in relation to annual performing surgeon volume of ruptured aortic abdominal aneurysm repair (open and endovascular) by quintiles.

Fig 5

Thirty-day mortality after ruptured aortic abdominal aneurysm surgery in relation to annual hospital volume of aortic abdominal aneurysm repair by quintiles: A, open (ruptured and elective), B, endovascular (ruptured and elective), or C, ruptured (open and endovascular). *P <.05 for volume quintiles vs the first quintile.

Fig 6

Kaplan-Meier survival analysis after ruptured aortic abdominal aneurysm surgery by hospital volume. A, survival after open repair of ruptured abdominal aortic aneurysm in relation to annual hospital volume of open aortic abdominal aneurysm repair (ruptured and elective) by quintiles. B, survival after endovascular repair of ruptured abdominal aortic aneurysm in relation to annual hospital volume of endovascular aortic abdominal aneurysm repair (ruptured and elective) by quintiles. C, survival after repair of ruptured abdominal aortic aneurysm in relation to annual hospital volume of ruptured aortic abdominal aneurysm repair (open and endovascular) by quintiles.