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 ... -  《-》

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 ... -  《-》

Higher surgeon annual volume, but not years of experience, is associated with reduced rates of postoperative complications and reoperations after open abdominal aortic aneurysm repair.

Volume-outcome relationships for open abdominal aortic aneurysm (AAA) repair have received less attention in publicly funded health systems. Furthermore, the roles of surgeon seniority (years of experience) and composite volume (encompassing all major arterial cases) on outcomes after open AAA repair are less well known. We sought to determine the effects of surgeon volume, surgeon years of experience, and composite volume on outcomes after elective open AAA repairs performed in Ontario, Canada. Using a population-based, prospectively collected health administrative database, all elective open AAA repairs occurring in the province of Ontario from 2005 to 2014 were identified. Surgeon annual volume was classified by quintiles, with the highest volume quintile acting as the reference category. Multivariable logistic regression modeling was used, adjusting for patient factors (age, sex, comorbidities, year of procedure, income) to investigate the relationship between surgeon annual volume and 30-day mortality, 30-day major complications, 30-day reoperations, 1-year mortality, and 1-year reoperations (related to index procedure). The potential effects of annual surgeon composite volume and surgeon years of experience on postoperative outcomes were also explored. A total of 7211 elective open AAA repairs performed by 101 surgeons were identified between 2005 and 2014. Most of the operations were performed by vascular surgeons (81.5%), followed by cardiac (12.1%) and general surgeons (6.1%). Median number of procedures in the lowest quintile group was 3 repairs/y, whereas the highest quintile group performed 54 repairs/y. Overall 30-day mortality was 3%. No difference in mortality was detected in comparing the lowest with the highest volume groups (1.89% vs 3.01%; adjusted odds ratio [OR], 0.60; 95% confidence interval [CI], 0.27-1.33). The lowest volume group exhibited a higher 30-day complication rate (28.0% vs 20.4%; OR, 1.54; 95% CI, 1.15-2.06) and 30-day reoperation rate (10.53% vs 6.73%; OR, 1.64; 95% CI, 1.13-2.38) compared with the highest volume group. No effect of surgeon volume on 1-year mortality or 1-year reoperation was observed. Similarly, composite volume and surgeon years of experience were not associated with postoperative outcomes. In a single-payer system with a relatively high number of open AAA repairs/surgeon per year, surgeon annual volume had no effect on postoperative mortality but was associated with lower postoperative complication and reoperation rates.

Dubois L ，Allen B ，Bray-Jenkyn K ，Power AH ，DeRose G ，Forbes TL ，Duncan A ，Shariff SZ ... -  《-》

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 ... -  《-》

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 ... -  《-》