Mortality variability after endovascular versus open abdominal aortic aneurysm repair in a large tertiary vascular center using a Medicare-derived risk prediction model.

Previous reports have documented better outcomes after open abdominal aortic aneurysm (AAA) repair in tertiary centers compared with lower-volume hospitals, but outcome variability for endovascular AAA repair (EVAR) vs open AAA repairs in a large tertiary center using a Medicare-derived mortality risk prediction model has not been previously reported. In the current study, we compared the observed vs predicted mortality after EVAR and open AAA repair in a single large tertiary vascular center. We retrospectively analyzed all patients who underwent repair of a nonruptured infrarenal AAA in our center from 2003 to 2012. Univariable and multivariable logistic regression were used to evaluate 30-day mortality. Patients were stratified into low-risk, medium-risk, and high-risk groups, and mortality was predicted for each patient based on demographics and comorbidities according to the Medicare risk prediction model. We analyzed 297 patients (EVAR, 72%; open AAA repair, 28%; symptomatic, 25%). Most of our patients were of high and moderate risk (48% and 28%, respectively). The observed 30-day mortality was 1.9% after EVAR vs 2.4% after open repair (odds ratio [OR], 0.77; 95% confidence interval [CI], 0.14-4.29; P = .67). There was no difference in mortality with EVAR vs open repair after adjusting for predefined patient characteristics (OR, 0.92; 95% CI, 0.16-7.43; P = .93); only preoperative renal disease was predictive of 30-day mortality after AAA repair in our cohort (OR, 8.39; 95% CI, 1.41-67.0). The observed mortality within our study was significantly lower than the Medicare-derived expected mortality for each treatment group within patients stratified as high risk or medium risk (P ≤ .0002 for all). Despite treating patients with high preoperative risk status, we report a 10-fold decrease in operative mortality for EVAR and open AAA repair in a tertiary vascular center compared with national Medicare-derived predictions. High-risk patients should be considered for aneurysm management in dedicated aortic centers, regardless of approach.

Hicks CW ，Black JH 3rd ，Arhuidese I ，Asanova L ，Qazi U ，Perler BA ，Freischlag JA ，Malas MB ... -  《-》

Surgeon case volume, not institution case volume, is the primary determinant of in-hospital mortality after elective open abdominal aortic aneurysm repair.

Studies analyzing the effects of volume on outcomes after abdominal aortic aneurysm (AAA) repair have primarily centered on institutional volume and not on individual surgeon volume. We sought to determine the relative effects of both surgeon and institution volume on mortality after open and endovascular aneurysm repair (EVAR) for intact AAAs. The Nationwide Inpatient Sample (2003-2007) was queried to identify all patients undergoing open repair and EVAR for nonruptured AAAs. To calculate surgeon and institution volume, 11 participating states that record a unique physician identifier for each procedure were included. Surgeon and institution volume were defined as low (first quintile), medium (second, third, or fourth quintile), and high (fifth quintile). Stratification by institution volume and then by surgeon volume was performed to analyze the primary endpoint: in-hospital mortality. Multivariable models were used to evaluate the association of institution and surgeon volume with mortality for open repair and EVAR, controlling for potential confounders. During the study period, 5972 open repairs and 8121 EVARs were performed. For open AAA repair, a significant mortality reduction was associated with both annual institution volume (low <7, medium 7-30, and high >30) and surgeon volume (low ≤ 2, medium 3-9, and high >9). High surgeon volume conferred a greater mortality reduction than did high institution volume. When low and medium volume institutions were stratified by surgeon volume, mortality after open AAA repair was inversely proportional to surgeon volume (8.7%, 3.6%, and 0%; P < .0001, for low, medium, and high-volume surgeons at low-volume institutions; and 6.7%, 4.8%, and 3.3%; P = .02, for low, medium, and high-volume surgeons at medium-volume institutions). High-volume institutions stratified by surgeon volume demonstrated the same trend (5.1%, 3.4%, and 2.8%), but this finding was not statistically significant (P = .57). Multivariable analysis was confirmatory: low surgeon volume independently predicted mortality (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.3-3.1; P < .001); low institution volume did not (P = .1). For EVAR, neither institution volume nor surgeon volume influenced mortality (univariate or multivariable). The primary factor driving the mortality reduction associated with case volume after open AAA repair is surgeon volume, not institution volume. Regionalization of AAAs should focus on open repair, as EVAR outcomes are equivalent across volume levels. Payers may need to re-evaluate strategies that encourage open AAA repair at high-volume institutions if specific surgeon volume is not considered.

McPhee JT ，Robinson WP 3rd ，Eslami MH ，Arous EJ ，Messina LM ，Schanzer A ... -  《-》

Failure to rescue trends in elective abdominal aortic aneurysm repair between 1995 and 2011.

Factors affecting mortality after abdominal aortic aneurysm (AAA) repair have been extensively studied, but little is known about the effects of the shift to endovascular aneurysm repair (EVAR) vs open repair on failure to rescue (FTR). This study examines the impact of treatment modalities on FTR for elective AAA surgery during the years 1995 to 2011. Data for 491,779 patients undergoing elective AAA surgery were collected from Medicare files. Patient demographics, comorbidities, hospital volume, and repair type were collected. Primary outcome was FTR: the percentage of deaths in patients who had a complication within 30 days of surgery. Data were analyzed by univariate and multivariate analysis. Patients undergoing AAA surgery have become progressively more complex, with 84.96%, 89.33%, 93.76%, and 95.72% presenting with one or more comorbidities in 1995, 2000, 2005, and 2011, respectively. Despite this, overall FTR after AAA surgery was stable from 1995 to 2000 (P = .38) and decreased from 2.68% to 1.58% between 2000 and 2011 (P < .001). In addition, FTR in EVAR decreased from 1.70% to 0.58% from 2000 to 2006 (P = .03) and then stabilized at 0.88% ± 0.9% after 2007 (P = .45). Unlike for EVAR, FTR for open repair remained stable at 3.06% ± 0.17% to 2.74% ± 0.16% from 1995 to 2000 (P = .38) but increased to 4.51% ± 0.21% in 2011 (P < .001). Mortality was highest after transfusion (20.86%), prolonged ventilation (17.37%), and respiratory complications (29.78%) for all AAA surgeries. Of note, high-volume hospitals had lower FTR rates than low-volume hospitals for both open (2.73% vs 5.66%; P < .001) and endovascular (0.7% vs 1.69%; P < .001) repair. Multivariate analysis showed that high annual volume hospital status (odds ratio, 0.6; confidence interval, 0.58-0.63) and endovascular repair (odds ratio, 0.3; confidence interval, 0.28-0.31) were associated with decreased FTR. The success in AAA surgery of rescuing patients from 30-day mortality after a complication is associated with increased volume of EVAR. This increased success can also be attributed to the improved FTR outcomes and complication rates when surgeries are performed at high-volume hospital centers.

Ilonzo N ，Egorova NN ，McKinsey JF ，Nowygrod R ... -  《-》

Effect of gender on long-term survival after abdominal aortic aneurysm repair based on results from the Medicare national database.

Historically, women have higher procedurally related mortality rates than men for abdominal aortic aneurysm (AAA) repair. Although endovascular aneurysm repair (EVAR) has improved these rates for men and women, effects of gender on long-term survival with different types of AAA repair, such as EVAR vs open aneurysm repair (OAR), need further investigation. To address this issue, we analyzed survival in matched cohorts who received EVAR or OAR for both elective (eAAA) and ruptured AAA (rAAA). Using the Medicare Beneficiary Database (1995-2006), we compiled a cohort of patients who underwent OAR or EVAR for eAAA (n = 322,892) or rAAA (n = 48,865). Men and women were matched by propensity scores, accounting for baseline demographics, comorbid conditions, treating institution, and surgeon experience. Frailty models were used to compare long-term survival of the matched groups. Perioperative mortality for eAAAs was significantly lower among EVAR vs OAR recipients for both men (1.84% vs 4.80%) and women (3.19% vs 6.37%, P < .0001). One difference, however, was that the survival benefit of EVAR was sustained for the 6 years of follow-up in women but disappeared in 2 years in men. Similarly, the survival benefit of men vs women after elective EVAR disappeared after 1.5 to 2 years. For rAAAs, 30-day mortality was significantly lower for EVAR recipients compared with OAR recipients, for both men (33.43% vs 43.70% P < .0001) and women (41.01% vs 48.28%, P = .0201). Six-year survival was significantly higher for men who received EVAR vs those who received OAR (P = .001). However, the survival benefit for women who received EVAR compared with OAR disappeared in 6 months. Survival was also substantially higher for men than women after emergent EVAR (P = .0007). Gender disparity is evident from long-term outcomes after AAA repair. In the case for rAAA, where the long-term outcome for women was significantly worse than for men, the less invasive EVAR treatment did not appear to benefit women to the same extent that it did for men. Although the long-term outcome after open repair for elective AAA was also worse for women, EVAR benefit for women was sustained longer than for men. These associations require further study to isolate specific risk factors that would be potential targets for improving AAA management.

Egorova NN ，Vouyouka AG ，McKinsey JF ，Faries PL ，Kent KC ，Moskowitz AJ ，Gelijns A ... -  《-》

Comparable mortality with open repair of complex and infrarenal aortic aneurysm.

A consequence of endovascular aneurysm repair (EVAR) of anatomically straightforward infrarenal abdominal aortic aneurysm repair cohort (AAA) is that open aneurysm repair is more commonly performed for complex anatomy. Complex aneurysm repair with visceral vessel involvement (CAA) or combined aneurysm repair and visceral vessel reconstruction (VVR) has traditionally been considered to increase morbidity and mortality compared with repair of infrarenal AAA. This study evaluated contemporary outcomes of open abdominal aneurysm surgery, including AAA, CAA, and VVR using the National Surgical Quality Improvement Program (NSQIP) database. The NSQIP Participant Use File was queried by CPT code to identify patients undergoing AAA, CAA, and VVR (2005-2008). Comparative analysis of clinical features, technical details and 30-day outcomes was performed using univariate methods. Logistic regression analysis was used to identify predictors of morbidity and mortality. A total of 2820 patients underwent AAA and 592 CAA. Renal insufficiency (ie, creatinine >1.4 mg/dL) rates were similar in AAA and CAA patients, however, more frequent in patients with VVR (51% vs 31% [no bypass]; P < .01). CAA was less likely to be performed urgently (6.3% vs 9.1%; P < .05) and was associated with increased operative time (254 ± 100 vs 224 ± 93; P < .01) compared with AAA. Univariate analysis showed that CAA did not increase mortality (5.7% vs 5.1%; P = .5). CAA slightly increased overall complications (32% vs 27%; P = .01) compared with AAA. 73 (2.5%) AAA and 84 (12%) CAA patients had simultaneous VVR and these patients exhibited a trend toward increased mortality (8.9% vs 5.2%; P = .07). VVR increased complications (43% (VVR) vs 26% [no bypass]; P < .01), including ventilation >48 hours (21% [VVR] vs 12% [no bypass]; P < .01), renal failure (7.6% [VVR] vs 4.1% [no bypass]; P = .04), and sepsis (13% [VVR] vs 6.3% ([no bypass]; P < .01). Multivariate analysis demonstrated that CAA (odds ratio [OR], 1.3 [95% confidence interval (CI), 1.1-1.6]; P = .01) and VVR (OR, 2.2 [95% CI, 1.8-3.6]; P < .01) increased the odds of any complication. Independent predictors of mortality included dependent functional status (OR, 3.6 [95% CI, 2.3-5.4]; P < .01), elevated pre-op creatinine (OR, 2.9 [95% CI, 2.2-4.0]; P < .01), type II diabetes (OR, 1.6 [95% CI, 1.05-2.4]; P = .03), and age (OR, 1.06 [95% CI, 1.03-1.08]; P < .01). Neither CAA (OR, 1.2 [95% CI, 0.84-1.8]; P = .3) nor VVR (OR, 1.6 [95% CI, 0.89-2.9]; P = .11) were associated with increased mortality compared with AAA. In contemporary practice the migration of open repair to increasingly complex cases has been achieved with 30-day mortality essentially equivalent to open repair of infrarenal AAA. Patients who require VVR do sustain increased complications, in particular renal failure. These data also emphasize the importance of baseline renal insufficiency in clinical decision making. CAA and VVR are associated with increased morbidity in comparison to AAA repair; however, both procedures can be safely performed in patients without increased risk of operative mortality.

Patel VI ，Lancaster RT ，Conrad MF ，Lamuraglia GM ，Kwolek CJ ，Brewster DC ，Cambria RP ... -  《-》