Prognostic value of left ventricular hypertrophy in patients with myocardial fibrosis by ECV mapping on cardiac MRI

Abstract

Abstract Background Cardiovascular magnetic resonance (CMR) can noninvasively identify myocardial fibrosis using extracellular volume (ECV) mapping. In patients with elevated ECV, and without hypertrophic cardiomyopathy (HCM) or cardiac amyloidosis, the prognostic significant of mild-to-moderate left ventricular hypertrophy (LVH) has not been well established. Purpose To determine if the presence of mild to moderate LVH has an impact on major adverse cardiovascular outcomes (MACE) in patients with elevated ECV without HCM or cardiac amyloidosis. Methods This was a retrospective cohort study assessing a group of patients referred for CMR between July 2019 and January 2023 to Mount Sinai Morningside. Patients with ECV>30% and left ventricular wall thickness <1.6 cm (to exclude patients with the possible diagnosis of HCM or cardiac amyloidosis) were considered for inclusion. Those with an established diagnosis of HCM or cardiac amyloidosis were also excluded. The LVH group comprised of patients with mild-to-moderate LVH, defined as a maximum wall thickness of 1.2-1.5 cm. The control group included patients without LVH (wall thickness <1.2 cm). Patients were further stratified by ECV, using the median value for our sample, as "high ECV" (≥35%) or "low ECV" (<35%). The outcome of interest was time-to-first MACE (all-cause death, or incident acute coronary syndrome, acute heart failure, or arrhythmia). Time-to-first MACE within 1 year was compared among groups using unadjusted Kaplan-Meier curves. Additional Cox regression analyses were performed to adjust for significant univariate analysis, including hypertension, hyperlipidemia, diabetes mellitus, use of beta-blocker, use of diuretic, and category of glomerular filtration rate. The results are presented as hazard ratios and 95% confidence intervals. All analyses were performed in SAS Enterprise using α<0.05. Results Out of the cohort, we identified 186 patients that met our selection criteria. The mean age was 61.1 ± 15.5 years, and 58.1% of patients were female. The median follow-up was 175 days in the control group and 115 days in the LVH group. There were 61 MACE (32.8%) in our sample. After adjusting for covariates, mild-to-moderate LVH was associated with 2.2 times the risk of MACE (95%CI 1.3 to 3.8; p=0.0047) at 1 year, compared to patients without LVH. A higher ECV (≥35%) was not significantly associated with worse outcomes within each study arm (p=0.3450). Kaplan Meier survival curves for patients with and without LVH are shown in Figure 1 (p=0.0002). Conclusions In patients with evidence of elevated ECV without underlying cardiac amyloidosis or hypertrophic cardiomyopathy, mild-to-moderate LVH is associated with 2.2 times the risk of MACE compared to normal left ventricular wall thickness.Figure 1