Myocardial hypertrophy: the differentiation of uremic, hypertensive, and hypertrophic cardiomyopathies by cardiac MRI.

Objectives: To apply cardiac magnetic resonance imaging (CMR) for detailed myocardial characterization in uremic cardiomyopathy (UC), hypertensive cardiomyopathy (HTN), and hypertrophic cardiomyopathy (HCM) aiming to enrich the understanding of UC's etiology and further support the development of therapeutic strategies.

Methods: A total of 152 patients (age: 49.2 ± 9.9 years; 65.8% male) underwent routine CMR from June 2016 to March 2023. Retrospectively, 53 patients with UC, 39 patients with HTN, 30 patients with HCM, and 30 healthy controls were included. Functional analysis, feature tracking of the left ventricle and left atrium, and myocardial T1, T2, and T2* mapping were performed. Statistical analysis included Pearson correlation and ROC analysis to define correlations and discriminators between groups.

Results: UC patients demonstrated significantly higher native T1 (p < 0.001 for all) and T2 (p < 0.002 for all) values compared with the other three groups. UC patients revealed higher left atrial reservoir strain rate (p < 0.001 for all) and left atrial conduit strain rate (p < 0.001 for all) absolute values as compared with HTN and HCM patients. A significant correlation between T1 and T2 values in UC patients (r = 0.511, p < 0.001) was found. The combination of T1 values and strain parameters was the best discriminator between UC and HTN patients (AUC = 0.872, 95% CI: 0.801-0.943) and between UC and HCM patients (AUC = 0.840, 95% CI: 0.746-0.934).

Conclusion: UC reveals distinguishing tissue characteristics as evidenced by T1 and T2 mapping, as well as distinguishing functional strain parameters as compared with other hypertrophic phenotypes such as HTN and HCM.

Critical Relevance Statement: The use of CMR imaging in UC patients offers incremental information to elucidate its complex etiology, contributing to ongoing discourse on effective treatment pathways.

Key Points: This study investigated uremic, hypertensive, and hypertrophic cardiomyopathies using cardiac MRI. UC patients have higher T1 and T2 values and better preserved cardiac function. Combined strain and T1 values distinguish UC from other cardiomyopathies.