Outcomes following emergent open repair for thoracic aortic dissection are improved at higher volume centers

Previous studies have demonstrated that patients undergoing complex surgical procedures at high-volume centers have improved outcomes. The goal of this study was to determine if this volume-outcomes relationship persists at a national level among patients undergoing emergent open repair for thoracic aortic dissection.

De-identified patient-level data were obtained from the Nationwide Inpatient Sample (2005 to 2008). Patients undergoing emergent aortic surgery for thoracic aortic dissection (n = 1230) were identified by ICD-9 codes and stratified by annual center volume into low volume (≤5 cases/year), intermediate volume (6 to 10 cases/year), and high volume (≥11 cases/year). The Deyo-Charlson co-morbidity score was used to adjust for differences in comorbidity between groups. Major outcomes of interest included: in-hospital morbidity and mortality, length of hospitalization, total hospital costs, and discharge disposition.

There was a significant association between in-hospital mortality and center volume (p = 0.014), with low, intermediate, and high-volume centers having mortality rates of 23.4% (n = 187), 20.1% (n = 62), and 12.1% (n = 15), respectively. This relationship persisted when controlling for severity of co-morbid illness (p = 0.007). The number of complications per patient varied significantly by center volume (p = 0.044), with a higher proportion of patients at high-volume centers having no complications. Also, the highest proportion of home discharges was observed among patients at high-volume centers (p = 0.011).

Survival following emergent open repair for thoracic aortic dissection was significantly greater at high-volume centers. These findings suggest that understanding the processes at high-volume centers that underlie this volume-outcomes relationship may improve in-hospital survival and postoperative complications.