Outcomes of Left Heart Bypass Versus Circulatory Arrest in Elective Open Surgical Descending and Thoraco-abdominal Aortic Repair

Abstract

To compare early (30 day mortality and major complications) and midterm (survival) outcomes in elective open surgical descending and thoraco-abdominal aortic repair using left heart bypass (LHB) versus hypothermic circulatory arrest (HCA) for organ protection, hypothesising non-inferiority of HCA management. This was a retrospective clinical cohort study with cross sectional follow-up. All elective (n=90) descending or thoraco-abdominal aortic repairs performed between 2004 and 2015 using either LHB (n=57) or HCA (n=33) were included. Pre- and intra-operative variables were evaluated by univariate statistical analysis. Thirty day and follow-up mortality were primary endpoints; major complications were secondary endpoints. Propensity score matching was employed to adjust for selection bias. Kaplan-Meier methods were used to estimate midterm survival. Overall 30 day mortality was 8/90 (8.9%): 6/57 (10.5%) using LHB vs. 2/33 (6.1%) using HCA, p=.47. Five patients (5.6%) suffered paraplegia: 3/57 (5.3%) using LHB vs. 2/33 (6.1%) using HCA, p=.87. Stroke occurred in 6/57 (11%) vs. 2/33 (6.1%), p=.76; renal failure in 27/57 (47%) vs. 19/33 (58%), p=.90; and respiratory failure in 17/57 (30%) vs. 11/33 (33%), p=.68. In 26 propensity score matched pairs, findings remained unaltered. Total follow-up was 443 patient years (median 4.9 years). Estimated survival was 78% at 1year and 77% at 5 years in LHB vs. 72% and 67%, respectively, with HCA; there were no significant inter-group differences, before or after propensity score matching. In elective descending or thoraco-abdominal aortic repair, no statistically significant differences in 30 day mortality, major complications, or follow-up survival were found when LHB and HCA were compared. These findings remained after propensity score matching.