Outcome After Open and Laparoscopic Aortic Surgery in Matched Cohorts Using Propensity Score Matching

Abstract

To compare the post-operative and mid-term outcomes of laparoscopic aortic surgery with those of conventional aortic surgery performed by a surgical team trained in laparoscopic aortic surgery. A prospective study was conducted between January 2006 and December 2011 with 228 consecutive patients having undergone aortic bypass surgery for either an abdominal aortic aneurysm (n=139) or occlusive aorto-iliac disease (n=89). Conventional open aortic surgery was carried out in 145 patients, and total laparoscopic repair in 83 patients. The composite primary end point measure grouped together the following adverse events (AEs): (1) any deaths<30 days or later deaths related to the operation; (2) post-operative hemorrhage necessitating reoperation; (3) myocardial infarction≤30 days; (4) stroke≤30 days; (5) post-operative respiratory failure necessitating re-intubation or assisted ventilation≥4 days; (6) aortic prosthesis infection; (7) aortic prosthesis occlusion; (8) any re-operation related to aortic surgery. In order to diminish bias attributable to the absence of randomization, the two surgical groups were matched by a propensity score enabling analysis of 50 pairs of patients having presented with identical pre-operative characteristics. Univariate analysis of the AE occurring during the first 30 post-operative days was followed by multivariate analysis through logistic regression. The rate of AE during follow up was calculated using the Kaplan-Meier method and the roles of the different co-variables were analyzed using the Cox model. Univariate analysis of the groups adjusted for propensity score showed that laparoscopic repair was associated with a significantly higher risk of AE over the first 30 post-operative days (p=.03). Logistic regression analysis showed that laparoscopic aortic technique (odds ratio [OR] 4.50; p=.01) and coronary artery disease (OR 4.67; p=.02) were independently related to the occurrence of an AE during the post-operative period. The occurrence of AEs during follow up was analyzed using the Cox model. Only two variables, laparoscopic aortic surgery (hazard ratio [HR] 4.40; p = .002) and coronary artery disease (HR 2.70, p = .02), were independently associated with the occurrence of an AE during follow up. The small number of patients included prevented a separate analysis with regard to aneurysmal and occlusive aortic disease. This study suggests that even with a well trained surgical team, the laparoscopic approach increases the risk for AEs observed in the course of aortic surgery. ClinicalTrials.gov Identifier: NCT02325700.