You Can't Find What You Aren't Looking For: Over Half of Heart Transplant Patients Have Moderate or Strong Likelihood of Genetic Disease

Abstract

Approximately half of patients undergoing heart transplant (HTX) have a primary cardiomyopathy. There is growing evidence for a genetic basis in many primary cardiomyopathies, with HFSA guidelines recommending genetics evaluations for many of these. We sought to assess the frequency of genetic disease in a single HTX center. Chart review of consecutive patients scheduled in the post-HTX clinic from 6/2019 to 09/2019. Patients were divided into four categories of probability of genetic etiology based upon their pre-HTX diagnosis and family history, per their cardiologist (Figure 1). Guideline-indicated cardiovascular genetics evaluations were initiated and the frequency of positive genetic testing, abnormal family history, and at-risk relatives needing screening were assessed. Of 53 patients, 42 (79%) had pre-HTX diagnosis with a "very likely," "likely," or "possible" genetic basis. More than half of patients (n=29, 54%) had a pre-HTX diagnosis with strong (n=18) or moderate (n=11) probability of genetic disease, corresponding to a mean of 5.8 patients per clinic having an indication for a cardiovascular genetics evaluation. Familial and idiopathic dilated cardiomyopathy were the most common diagnoses of strong and moderate suspicion (n=25, 47%). Of the 23 patients evaluated to date, 10 (43%) had a positive genetic test result. Comprehensive 3-4 generation family histories taken by a cardiovascular genetic counselor revealed evidence of familial disease in 21 of 23 patients (91.3%). Cardiovascular evaluations are indicated in a mean of 7.7 relatives per patient. More than half of HTX patients have an indication for referral to cardiovascular genetics. HTX patients should be proactively screened for potential genetic etiology and referred for genetic counseling and testing given the potential impact on their family members.