Cardiovascular Complications After Liver Transplant: A Shifting Clinical Presentation

SEE ARTICLE ON PAGE 1398 Predicting cardiovascular complications after liver transplantation (LT) has traditionally focused on acute coronary syndrome (ACS). Major noncardiac surgery is a well‐known risk factor for ACS,1 and immunosuppressive medications are known to accelerate atherosclerosis.2 Transplant programs typically have protocols for pretransplant cardiovascular risk stratification to identify transplant candidates at highest risk for cardiac events and to employ medical and surgical interventions to mitigate cardiovascular risk.1 In our program, we use the Framingham risk calculator to guide individualized testing protocols,3 and fortunately, posttransplant ACS has become a rare event. The report by Khurmi et al.4 in this issue of Liver Transplantation reflects a shift in clinical presentation, which we have noticed in our own practice: most posttransplant cardiovascular complications are now non‐ACS in nature. The authors note that among 4763 hospitalizations for cardiovascular complications in LT recipients, fewer than 10% of these complications were related to ACS (myocardial infarction or cardiac arrest). Conversely, dysrhythmias and congestive heart failure were both nearly 10‐fold more common, increasing in frequency over time. Although limited by the inability to determine timing of these hospitalizations after LT, this finding is clinically relevant because it suggests the need for transplant programs to develop risk stratification methods for non‐ACS complications. One particularly early clinical presentation that has occurred in 7/154 (5%) of our LT recipients in the past 2.5 years is acute nonischemic cardiomyopathy with a low ejection fraction. Although the pathophysiology of this entity is not well understood, it is thought to be related to massive catecholamine exposure and may be precipitated in LT recipients by preexisting structural changes associated with cirrhotic cardiomyopathy.5 Although referred to as “stress‐induced” or “takotsubo” cardiomyopathy in the literature, posttransplant cardiomyopathy can be associated with poor outcomes and thus may be a different clinical entity.6 Additional research is certainly needed, but several existing techniques may help identify patients with pretransplant cardiomyopathy and those at increased risk for posttransplant cardiomyopathy. Elevated right‐sided pressures, particularly in older patients, with any degree of right heart dysfunction are a major risk factor.7 Other risk factors include QT interval prolongation, systolic or diastolic left ventricular dysfunction, left ventricular hypertrophy, or elevated prohormone brain natriuretic peptide levels.8 In addition to preoperative risk factors, the major determinant of posttransplant cardiomyopathy may be what happens in the operating room. Further studies are needed to identify quasi‐modifiable factors such as blood transfusion, catecholamine usage, and management of the reperfusion syndrome. Finally, it remains unclear whether using beta‐blockers in the immediate posttransplant period would increase or decrease the incidence of cardiomyopathy. The second major finding of the Khurmi et al. study is that counter to what might have been expected, patients admitted at transplant hospitals had higher risk‐adjusted mortality than those admitted at nontransplant hospitals. We agree with the authors that this very well may reflect differences in coding and adverse selection, but a true underlying systematic difference cannot be discounted. One possible explanation could be that patients at transplant hospitals tend to be admitted to the transplant service, which is not as familiar with managing cardiovascular complications. However, the most likely explanation is that the sickest patients and those readmitted multiple times end up at transplant hospitals, and these factors are incompletely captured in risk adjustment. In summary, cardiovascular complications after LT remain very common but have shifted away from ACS to cardiomyopathy and dysrhythmias. LT programs would be wise to partner with their cardiologists to develop protocols for risk stratification and management of these conditions. Potential conflict of interest Nothing to report.