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 ... -  《-》

Endovascular treatment of ruptured abdominal aortic aneurysms in the United States (2001-2006): a significant survival benefit over open repair is independently associated with increased institutional volume.

McPhee J ，Eslami MH ，Arous EJ ，Messina LM ，Schanzer A ... -  《-》

Defining the type of surgeon volume that influences the outcomes for open abdominal aortic aneurysm repair.

Prior studies have reported improved clinical outcomes with higher surgeon volume, which is assumed to be a product of the surgeon's experience with the index operation. We hypothesized that composite surgeon volume is an important determinant of outcome. We tested this hypothesis by comparing the impact of operation-specific surgeon volume versus composite surgeon volume on surgical outcomes, using open abdominal aortic aneurysm (AAA) repair as the index operation. The Nationwide Inpatient Sample was analyzed to identify patients undergoing open AAA repairs for 2000 to 2008. Surgeons were stratified into deciles based on annual volume of open AAA repairs ("operation-specific volume") and overall volume of open vascular operations ("composite volume"). Composite volume was defined by the sum of several open vascular operations: carotid endarterectomy, aortobifemoral bypass, femoral-popliteal bypass, and femoral-tibial bypass. Multiple logistic regression analyses were used to examine the relationship between surgeon volume and in-hospital mortality for open AAA repair, adjusting for both patient and hospital characteristics. Between 2000 and 2008, an estimated 111,533 (95% confidence interval [CI], 102,296-121,232) elective open AAA repairs were performed nationwide by 6,857 surgeons. The crude in-hospital mortality rate over the study period was 6.1% (95% CI, 5.6%-6.5%). The mean number of open AAA repairs performed annually was 2.4 operations per surgeon. The mean composite volume was 5.3 operations annually. As expected, in-hospital mortality for open AAA repair decreased with increasing volume of open AAA repairs performed by a surgeon. Mortality rates for the lowest and highest deciles of surgeon volume were 10.2% and 4.5%, respectively (P < .0001). A similar pattern was observed for composite surgeon volume, as the mortality rates for the lowest and highest deciles of composite volume were 9.8% and 4.8%, respectively (P < .0001). After adjusting for patient and hospital characteristics, increasing composite surgeon volume remained a significant predictor of lower in-hospital mortality for open AAA repair (odds ratio, 0.994; 95% CI, .992-.996; P < .0001), whereas increasing volume of AAA repairs per surgeon did not predict in-hospital deaths. The current study suggests that composite surgeon volume-not operation-specific volume-is a key determinant of in-hospital mortality for open AAA repair. This finding needs to be considered for future credentialing of surgeons.

Modrall JG ，Rosero EB ，Chung J ，Arko FR 3rd ，Valentine RJ ，Clagett GP ，Timaran CH ... -  《-》

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 ... -  《-》

Measure what matters: institutional outcome data are superior to the use of surrogate markers to define "center of excellence" for abdominal aortic aneurysm repair.

Goshima KR ，Mills JL Sr ，Awari K ，Pike SL ，Hughes JD ... -  《-》