The Cardiovascular Magnetic Resonance Phenotype of Lamin Heart Disease

Lamin (LMNA) heart disease is a lethal form of dilated cardiomyopathy (DCM). The authors explored its cardiovascular magnetic resonance (CMR) phenotype to discover prognostically useful and subclinical biomarkers. This prospective multicenter study recruited 4 groups: LMNA carriers with left ventricular ejection fraction ≥55% (Lamin+EF), LMNA carriers with left ventricular ejection fraction <50% (Lamin-EF), individuals with DCM with wild-type LMNA (DCMwt), and healthy volunteers. Phantom-calibrated CMR comprising cines, late gadolinium enhancement, and multiparametric mapping was undertaken. Left ventricular shapes were reconstructed using generalized Procrustes analysis. Serum biomarkers were collected at the time of CMR. Using a major adverse cardiovascular events (MACE) outcome of cardiovascular death, life-threatening ventricular tachyarrhythmia, heart transplantation, or atrioventricular block requiring pacing, we explored the prognostic value of CMR metrics using Cox regression. A total of 187 individuals were recruited (50% male): 29 with Lamin+EF (38 ± 14 years), 38 with Lamin-EF (45 ± 17 years), 73 with DCMwt (45 ± 15 years), and 47 healthy volunteers (44 ± 20 years). Compared to HVs, Lamin+EF had longer phantom-normalized T2 by 10 (95% CI: 2-20), higher ECV by 3% (95% CI: 1%-6%), and worse myocardial dynamics. Compared with DCMwt participants, Lamin+EF participants had better myocardial dynamics, higher phantom-normalized T2 (20 vs 12; P = 0.010), higher serum troponin (27 ng/L vs 5 ng/L; P < 0.001), and higher C-reactive protein (8 mg/L vs 3 mg/L; P = 0.021). Lamin-EF participants had similar myocardial dynamics but higher serum troponin (13 ng/L vs 5 ng/L; P < 0.001), higher N-terminal pro-B-type natriuretic peptide (668 pg/mL vs 228 pg/mL; P = 0.025), longer phantom-normalized T2 by 16 (95% CI: 1-31), and higher extracellular volume by 5% (95% CI: 1%-9%) than DCMwt participants. Over 4 years, 21% of lamin and 6% of DCMwt participants experienced MACE (P < 0.001). In lamin participants, each 1% increase in global late gadolinium enhancement and each 1% decrease in Procrustes trajectory sizes associated with HRs for MACE of 1.15 (95% CI: 1.02-1.30) and 1.01 (95% CI: 1.01-1.02), respectively (both P ≤ 0.025). The CMR phenotype of LMNA carriers with preserved left ventricular systolic function consists of longer T2, higher serum troponin levels, higher extracellular volume, and impaired strain. CMR-derived focal fibrosis and strain biomarkers are prognostic, and future studies should explore their added clinical utility beyond the currently available MACE risk prediction tools. (The Deep Phenotype of Lamin A/C Cardiomyopathy; NCT03860454).