Left heart bypass versus circulatory arrest for open repair of thoracoabdominal aortic pathologies

Background Most large-volume centres use left heart bypass (LHB) as their preferred organ protection strategy during repair of descending thoracic aortic (DTA) and thoracoabdominal aortic (TAA) pathologies. We investigate the use of hypothermic circulatory arrest (HCA) for similar pathologies and compare the outcomes of both. Methods A PubMed, Embase and Scopus search for studies in English on LHB versus HCA for repair of DTA and TAA pathologies published from inception till February 2020 was performed. Our analysis excluded studies without direct comparison of the two organ protection strategies. Clinical endpoints that were studied were 30-day mortality, post-operative stroke, spinal cord deficit, renal failure and respiratory failure. Random effects meta-analyses of the effect of the two strategies across all clinical endpoints were conducted. Results HCA is non-inferior to LHB across all clinical endpoints. In terms of 30-day mortality (odds ratio (OR) 1.19, 95% confidence interval (CI) 0.31-4.59,P= 0.14,I-2= 49%), stroke (OR 0.41, 95% CI 0.12-1.39,P= 0.97,I-2= 0%), spinal cord deficit (OR 0.56, 95% CI 0.22-1.45,P= 0.78,I-2= 0%), renal failure (OR 1.33, 95% CI 0.37-4.76,P= 0.98,I-2= 0%) and respiratory failure (OR 0.86, 95% CI 0.37-1.97,P= 0.16,I-2= 46%), there was no statistically significant difference between the two cohorts. Conclusion Evidence is limited, but suggests that HCA alone provides adequate organ protection during repair of DTA and TAA pathologies, and has equivalent outcomes when compared to LHB.