Analysing the Society for Vascular Surgery and American Association for Vascular Surgery scoring systems for outcomes post-endovascular aortic repair

Background and aims: Assess the association between the Society for Vascular Surgery/American Association for Vascular Surgery (SVS/AVSS) (Rutherford et al., J Vasc Surg 26: 517–38, 1997; Chaikof et al., J Vasc Surg 35:1061–6, 2002) medical comorbidity scoring scheme (MCS), and the global scoring system (GS) and major morbidity and mortality after elective endovascular aneurysm repair. Primary end points were peri-operative morbidity and mortality. Secondary end points were intensive care unit admission, high dependency unit admission, total stay > 5 days and 2-year mortality. Methods: The project was approved by the Galway Clinical Research Ethics Committee. This project followed the Declaration of Helsinki. Binary logistic regression was performed to assess the association of the scores and their individual components with the primary and secondary outcomes. Results were reported as odds ratio (OR) per point increase in score with 95% confidence intervals (CI) and the Hosmer-Lemeshow (HL). Results: Between 2002 and 2015, 401 patients underwent elective EVARs. MCS was calculated for 396 patients while GS was calculated for 183 patients. The MCS (OR 1.906, CI 1.017–3.574, p = 0.044) was associated with perioperative morbidity. The MCS was associated with perioperative mortality (OR 8.875, CI 1.918–41.070, p = 0.005). The GS was associated with perioperative morbidity (OR 11.929, CI 1.151–123.584, p =.038) but not associated with perioperative mortality (OR 3.62, CI 0.006–2118.148, p =.692). Conclusions: The MCS shows association with perioperative morbidity and mortality. GS shows association with perioperative morbidity but not perioperative mortality; however, this may be due to our study being underpowered. We believe that the analysis of higher numbers of patients could unmask trends in both of these scores and individual components of both scores changed.