Perioperative Cardiovascular Risk Assessment and Management in Liver Transplant Recipients: A Review of the Literature Merging Guidelines and Interventions

Liver transplantation (LT) is the second most performed solid organ transplant. Coronary artery disease (CAD) is a critical consideration for LT candidacy, particularly in patients with known CAD or risk factors, including metabolic dysfunction associated with steatotic liver disease. The presence of severe CAD may exclude patients from LT; therefore, precise preoperative evaluation and interventions are necessary to achieve transplant candidacy. Cardiovascular complications represent the earliest nongraft-related cause of death post-transplantation. Timely intervention to reduce cardiovascular events depends on adequate CAD screening. Coronary disease screening in end-stage liver disease is challenging because standard noninvasive CAD screening tests have low sensitivity due to hyperdynamic state and vasodilatation. As a result, there is overuse of invasive coronary angiography to exclude severe CAD. Coronary artery calcium scoring using a computed tomography scan is a tool for the prediction of cardiovascular events, and can be used to achieve risk stratification in LT candidates. Recent literature shows that qualitative assessment on both noncontrast- and contrast-enhanced chest computed tomography can be used instead of calcium score to assess the presence of coronary calcium. With increasing prevalence, protocols to address CAD in LT candidates must be reconsidered. Percutaneous coronary intervention could allow a shorter duration of dual-antiplatelet therapy in simple lesions, with safer perioperative outcomes. Hybrid coronary revascularization is an option for high-risk LT candidates with multivessel disease nonamenable to percutaneous coronary intervention. The objective of this review is to evaluate existing methods for preoperative cardiovascular risk stratification, and to describe interventions before surgery to optimize patient outcomes and reduce cardiovascular event risk.

Postoperative troponin surveillance to detect myocardial infarction: an observational cohort modelling study

BACKGROUND

Clinical presentation of postoperative myocardial infarction (POMI) is often silent. Several international guidelines recommend routine troponin surveillance in patients at risk. We compared how these different guidelines select patients for surveillance after noncardiac surgery with our established risk stratification model.

METHODS

We used outcome data from two prospective studies: Measurement of Exercise Tolerance before Surgery (METS) and Troponin Elevation After Major non-cardiac Surgery (TEAMS). We compared the major American, Canadian, and European guideline recommendations for troponin surveillance with our established risk stratification model. For each guideline and model, we quantified the number of patients requiring monitoring, % POMI detected, sensitivity, specificity, diagnostic odds ratio, and number needed to screen (NNS).

RESULTS

METS and TEAMS contributed 2350 patients, of whom 319 (14%) had myocardial injury, 61 (2.5%) developed POMI, and 14 (0.6%) died. Our risk stratification model selected fewer patients for troponin monitoring (20%), compared with the Canadian (78%) and European (79%) guidelines. The sensitivity to detect POMI was highest with the Canadian and European guidelines (0.85; 95% confidence interval [CI] 0.74-0.92). Specificity was highest using the American guidelines (0.91; 95% CI 0.90-0.92). Our risk stratification model had the best diagnostic odds ratio (2.5; 95% CI 1.4-4.2) and a lower NNS (21 vs 35) compared with the guidelines.

CONCLUSIONS

Most postoperative myocardial infarctions were detected by the Canadian and European guidelines but at the cost of low specificity and a higher number of patients undergoing screening. Patient selection based on our risk stratification model was optimal.