VESS14. Hospital Volume Is Associated With Improved Outcomes of Elective and Urgent Thoracoabdominal Aortic Aneurysm Repair

Abstract

Contemporary data on outcomes in open thoracoabdominal aortic aneurysm (TAAA) repair are limited to reports from major aortic reference centers showing excellent outcomes. This study aimed to characterize the national experience of open TAAA repair using national outcomes data, with a primary focus on the influence of operative volume on mortality and morbidity. The Nationwide Inpatient Sample was queried from 1998 to 2011, and all patients with a diagnosis of TAAA who underwent open operative repair were included. Patients with a concomitant procedure code for cardioplegia, coronary bypass, heart valve surgery, and endovascular aortic repair were excluded, leaving 14,263 patients included in this analysis. These patients were further stratified into tertiles based on the operative volume of the institution that performed their operation: low volume (LV, <3 cases/y), medium volume (MV, 3-11 cases/y), and high volume (HV, >11 cases/y). Baseline demographics as well as perioperative outcomes were compared between these groups. Multivariable logistic regression was performed to determine predictors of operative mortality and morbidity. Subgroup analyses were performed for patients presenting for elective surgery (ESC) and for those presenting for urgent and emergent surgery (UEC). Overall operative mortality was 21% for the entire cohort. Operative mortality was higher at LV (26%) and MV (21%) centers compared with HV centers (15%; P < .05). This difference was similar in both the ESC (18% and 14% vs 12%) and the UEC (34% and 30% vs 19%). Furthermore, rates of blood transfusion and acute renal failure were significantly lower in the HV group. Multivariable analysis revealed that compared with the HV group, patients operated on at LV (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.7-2.1; P < .05) and MV (OR, 1.5; 95% CI, 1.4-1.7; P < .05) centers had at least 1.5 times the odds of in-hospital mortality. The HV group also has significantly lower odds of dying in the subgroup analyses of both the ESC and the UEC. Similarly, patients operated on at LV centers (OR, 1.3; 95% CI, 1.2-1.5; P < .05) had higher odds compared with HV centers of having major morbidity. National mortality for TAAA is much higher than the operative mortality quoted by national reference centers. Patients operated on at HV centers have a significant reduction in mortality and morbidity compared with other lower volume centers. This relationship is true in the elective as well as in the urgent/emergent population, suggesting referral to higher volume centers or centers of excellence for TAAA surgery when feasible.