Existing Models to Assess Perioperative Cardiac Risk Demonstrate Poor Predictive Validity in Patients Undergoing Liver Transplantation

Abstract

Background: Liver transplantation (LT) is associated with risk for perioperative cardiovascular events. Although guideline recommended risk scores are well validated in non-cardiac surgery, there is uncertainty regarding their utility in LT. Methods: Consecutive adult patients undergoing LT at the Victorian Liver Transplantation Unit between 2010 and 2017 were evaluated. Perioperative 30-day major adverse cardiovascular events (MACE) and all-cause death were recorded from a prospectively maintained transplantation database and supplemented by electronic medical record review. Perioperative risk for each patient was calculated using the Revised Cardiac Risk Index (RCRI), Charlson Comorbidity Index (CCI) and American Society of Anaesthesiologists Score (ASA) and subsequently assessed for predictive validity. Results: Among the 704 adult patients that underwent workup for LT, 462 proceeded to transplantation (mean age 52 ± 13, 67.5% male). A total of 51 (11%) patients had perioperative MACE within the 30-day post-operative period. Events included 26 episodes of cardiac failure, 15 resuscitated cardiac arrests, 16 acute coronary syndromes and 10 episodes of ventricular tachycardia. Predictive capability of the assessed scores is reported in Table 1. The risk predictive ability of the RCRI, CCI and ASA scores were low, with all reporting an area under the curve (AUC) <0.60. A high risk score, as defined by guideline recommendations, demonstrated a modest negative predictive value (NPV) and a low positive predictive value (PPV). Conclusion: Current preoperative risk prediction algorithms have poor predictive ability for cardiac events in a contemporary cohort of LT patients. Better risk prediction algorithms in this group of patients are warranted.