Optimizing Screening Intervals for At-Risk Relatives of Dilated Cardiomyopathy Carrying a TTNtv

BACKGROUND: Cardiomyopathy guidelines recommend routine screening of at-risk relatives with dilated cardiomyopathy (DCM). Titin-truncating variants are the most prevalent cause. However, the diagnostic yield of screening is low. Risk-based stratification could optimize screening intervals and resource allocation. This study aims to develop a safe, evidence-based gene-specific longitudinal screening algorithm for DCM development. METHODS: We included likely pathogenic/pathogenic titin-truncating variant relatives from 7 centers who underwent cardiac screening. Relatives were stratified based on their baseline clinical phenotype: genotype-positive/phenotype-negative (no left ventricular dysfunction and dilatation) or partial DCM (ie, fulfilling only 1 criterion). DCM development predictors were identified based on follow-up data. Risk profiles were established and used to develop a multistate model to create a longitudinal screening algorithm to safely and effectively monitor titin-truncating variant relatives. RESULTS: Among 413 relatives, follow-up data were available in 301 relatives (median follow-up 5.7 years), of whom 24.6% developed left ventricular dysfunction or dilatation and 17.3% developed DCM. In total, 16 relatives (5.3%) experienced a major adverse cardiac event after DCM diagnosis. Based on the identified risk factors, age ≥30 years, male sex, and partial DCM, 3 distinct profiles were established: (1) relatives with partial DCM, (2) females ≥30 years and males, and (3) female relatives <30 years. A screening algorithm was developed, recommending intervals of 1, 3, and 5 years, optimizing the balance between safety and effectiveness. CONCLUSIONS: An evidence-based genotype-specific longitudinal screening algorithm that integrates age, sex, and echocardiographic measurements may improve patient care and improve efficiency of clinical resource allocation.