Abstract 15590: Genetic Testing and Cardiac Magnetic Resonance Imaging Results Improve Precision Stratification in Dilated Cardiomyopathy

Abstract

Introduction: Dilated cardiomyopathy (DCM) has a heterogenous aetiology. Precise disease stratification enabling personalised therapy may be key to improving management. Genetic testing and cardiac magnetic resonance (CMR) may help stratify the cause of DCM. Hypothesis: Adding genetic testing and CMR to routine tests will improve confidence and reproducibility in DCM stratification and, in turn, guide management. Methods: Case profiles for 60 consecutive patients with DCM were sent to 4 independent experts. Using routinely available clinical information, they were asked to determine the aetiology of the phenotype, based on the classification in the ESC Position Statement on DCM, and record their confidence (score 1-3) in the diagnosis. This was repeated after the addition of genetic testing and CMR results in a step-wise manner. Clinicians were also asked whether they would make changes to patient management. Results: Overall, 4 physicians reviewed 60 cases, giving 240 responses. Adding genetic testing and CMR resulted in changes to disease stratification ( Table 1 ). The most common change was from idiopathic to genetic DCM, following the identification of pathogenic or likely pathogenic variants in 13 cases. Confidence scores improved with the addition of genetic testing and CMR results (routine 1.69±0.53; routine & genetic 1.93±0.61, p<0.0005; routine, genetic & CMR 2.26±0.69, p<0.0005). Adding genetic testing and CMR led to changes in management, with family screening the most common. Where LMNA or DSP variants were identified (n=3, 5.0%), new recommendations for device therapy were made. Adding genetic and CMR data improved interobserver agreement in stratification (routine κ=0.40; routine & genetic κ=0.66; routine, genetic & CMR κ=0.68). Conclusion: Adding genetic testing and CMR to routine tests changed how DCM was stratified, improved confidence and interobserver variability in making this diagnosis, and subsequently, directed management.