Assessment of Cardiac Risk Stratification in Liver Transplantation

Cardiac risk stratification based on traditional cardiac risk factors with the selective use of dobutamine stress echocardiography (DSE), computed tomography coronary angiography (CTCA), and coronary angiography (CA) is safe and efficacious in adult liver transplantation (LT) candidates. These findings are based on the results of a study published in the American Association for the Study of Liver Diseases.

Coronary artery disease (CAD) is associated with an increased perioperative risk in patients undergoing LT. Although routine screening for CAD is often advised, data on the effectiveness of screening strategies are limited. Thus, a team of investigators from the Austin Hospital in Melbourne, Australia, conducted a single-center, prospective, observational study to evaluate the safety and efficacy of a three-tiered cardiac risk stratification protocol in patients undergoing LT assessment.

Researchers stratified patients into 3 cardiac risk groups: low (LR), intermediate (IR), or high (HR) risk. They underwent standardized investigations with selective use of transthoracic echocardiography (TTE), DSE, CTCA, and CA. Cardiac events (CE) and cardiovascular death up to 30 days post-LT were the primary outcomes.

A total of 569 adult patients (76 LR; 256 IR; 237 HR) undergoing LT assessment at the Victorian Liver Transplant Unit from August 2010 to December 2017 were included in the study. The median age of the enrollees was 56 (interquartile range, 48-60) years, and 71.4% were male.

Cardiac risk factors were the following: diabetes (26%), smoking history (47%), hypertension (18%), dyslipidemia (7%), family (17%) or prior (6%) history of heart disease, and obesity (28%).

The investigators found that 42% of patients had ≥ 2 risk factors and overall adherence with the protocol was 90.3%.

Abnormal findings on TTE, DSE, and CTCA were noted in 3, 23 and 44 patients, respectively. In addition, 12 (2.2%) patients were deemed as unsuitable for LT  following cardiac assessment (1 LR, 2 IR, and 9 HR). The researchers identified moderate or severe CAD in 25% of patients with HR on CTCA undergoing a normal DSE.

A total of 397 patients received transplantation, and 7 CE (1.2%) were recorded with 2 cardiovascular deaths (0.4%).

This study was limited by the small number of patients who did not adhere to the protocol. Also, no association was found between non-alcoholic fatty liver disease and increased CE or delisting events. Lastly, additional studies are needed to evaluate the association between coronary microvascular dysfunction and CE, especially given the frequency of type 2 acute coronary syndrome in the cohort.

Nevertheless, this study was considered the largest prospective single-center series to evaluate the performance of cardiac risk stratification protocol in LT candidates.

The study authors concluded, “Cardiac risk stratification based on traditional cardiac risk factors with the selective use of DSE, CA and CTCA is a safe and feasible approach that results in low peri-operative CE and CVD rates.”

They added, “CTCA is well-tolerated in LT candidates and identifies CAD in a significant proportion of patients following normal DSE, which can affect suitability for transplantation.”

Reference

Robertson M, Chung W, Liu D, et al. Cardiac risk stratification in liver transplantation: results of a tiered assessment protocol based on traditional cardiovascular risk factors. Liver Transpl. Published online February 19, 2021. doi:10.1002/LT.26025