Genetic Testing Practices and Pathological Assessments in End Stage Heart Failure Patients Undergoing Heart Transplantation and Left Ventricular Assist Device.

Background: Genetic cardiomyopathies (CM) are increasingly recognized as causes of end-stage heart failure (ESHF). Identification of a genetic etiology in ESHF has important prognostic and family implications. However, genetic testing practices are understudied in ESHF patients.

Methods: This single-center, retrospective study included consecutive ESHF patients who underwent heart transplantation (HT) or left ventricular assist device (LVAD) from 2018 to 2023. Data, including genetic testing and pathology reports, were collected from the electronic medical record. Analyses of demographic and clinical characteristics were stratified by genetic testing completion and presence of clinically actionable variant. Logistic regression was performed to evaluate for associations between histology findings and genetic variants.

Results: A total of 529 adult patients (mean age 57 years) were included in the study and were predominantly male (79%, 422/529) and non-white (61%, 322/529). Genetic testing was performed in 54% (196/360) of patients with either non-ischemic or mixed CM. A clinically actionable result was identified in 36% (70/196) of patients, of which, only 43% (30/70) had a genetic counselor referral. The most common genetic variants were TTN (32%, 24/75), MYBPC3 (13%, 10/75), and TTR (11%, 8/75). Clinically actionable variants were identified in patients with known heart failure precipitators, such as alcohol use. In multivariable analysis, presence of interstitial fibrosis, specifically diffuse, on pathology was significantly associated with a clinically actionable variant (aOR 2.29, 95% CI [1.08-4.86], p = 0.03).

Conclusion: ESHF patients with non-ischemic or mixed CM undergoing advanced therapies had a low uptake of genetic services, including testing and counselors, despite a high burden of genetic disease. Pathology findings, such as interstitial fibrosis, may provide insight into genetic etiology. The underutilization of services suggests a need for implementation strategies to improve uptake.