Visual coronary artery calcium assessment on routine chest CT can readily and cheaply identify liver transplant recipients with a low cardiac risk

Abstract

Abstract Background Peri- and postoperative cardiac complications play an important role in survival of patients after liver transplantation (LT). However, the optimal approach for cardiac risk prediction in these patients has been debated on. LT recipients routinely receive non-gated computed tomography (CT) of the abdomen and chest to follow-up on their liver diseases. This study analyzed whether performance of coronary artery calcium (CAC) assessment on freely available scans can enhance cardiac risk stratification of LT recipients. Methods Consecutive LT recipients from 2008-2023 were included and analyzed retrospectively. CAC was scored visually on non-gated CT on a semi-quantitative ordinal scale and stratified in two groups according to CAC severity. Peri-operative (≤90 days) and post-operative all-cause mortality and cardiac events were analyzed. Furthermore, all-cause mortality and cardiac events were analyzed and compared between the groups with a Kaplan Meier curve and Cox proportional hazard regression. Results A total of 149 patients were included with a median age of 58 years. The median follow-up time was 5 years. The majority (74%) of patients had no or mild CAC. None of these patients died perioperatively due to cardiac causes, or experienced peri-operative cardiac events. The post-operative 10-year survival of LT recipients with no or mild calcifications was significantly better (p<0.01) than patients with severe CAC. The 10-year cardiac event-free survival was significantly better in patients with no or mild CAC (p<0.01) and the incidence increased >4-fold from only 4% in patients with no-mild CAC to 18% in patients with severe CAC. Of interest, severe CAC was a significant predictor of cardiac events (HR 4.6, p=0.02), while classical cardiovascular risk factors e.g. diabetes were not. Conclusion CAC assessment on routinely available non-gated CT can readily enhance peri- and postoperative cardiac risk stratification of LT recipients, as it identifies a selection of low-risk individuals for having peri- and post-operative cardiac events and all-cause mortality. Thereby, reducing test burden for the patients and saving healthcare expenses.