Predictive value of cardiac magnetic resonance in ambulatory patients with non-ischemic dilated cardiomyopathy and elevated NT-proBNP levels
V Popadic, M Popovic, P Zafirovska, D Zdravkovic, P Djuran, N Ninkovic, L Memon, S Klasnja, M ZdravkovicAbstract
Background
In patients with non-ischemic dilated cardiomyopathy (NIDCM), risk stratification remains challenging, particularly in clinically stable patients with persistently elevated N-terminal pro–B-type natriuretic peptide (NT-proBNP) levels in the ambulatory setting. Cardiac magnetic resonance (CMR) offers comprehensive ventricular function assessment and myocardial tissue characterization, which may provide incremental prognostic value beyond biomarkers alone.
Materials and Methods
This prospective longitudinal study included 84 stable ambulatory patients with previously diagnosed NIDCM and elevated NT-proBNP levels. All patients underwent comprehensive CMR at baseline, while follow-up CMR examinations were performed at 1 and 2 years. Patients were followed for 24 months for the occurrence of heart failure–related hospitalizations. The predictive value of baseline and longitudinal CMR parameters for adverse outcomes was assessed.
Results
Eighty-four stable ambulatory patients with non-ischemic dilated cardiomyopathy and elevated NT-proBNP levels were followed for 24 months. The majority of patients were in NYHA II (57%) and NYHA III class (29%), while 26 patients (31%) experienced heart failure hospitalization during the follow-up period. Mean ambulatory NT-proBNP levels at baseline were 1245 ± 610 pg/mL (range 420–3280 pg/mL). At baseline, patients with events had higher LV end-diastolic volume index (HR per 10 mL/m² increase 1.18, 95% CI 1.01–1.38; P = 0.04), lower left ventricular ejection fraction (34.6 ± 6.9% vs. 42.8 ± 7.4%; P<0.001), higher global T2 (HR per 1 ms increase 1.14, 95% CI 1.02–1.27; P = 0.02), and native T1 (HR per 10 ms increase 1.16, 95% CI 1.02–1.31; P = 0.02), higher prevalence of LGE (69% vs. 32%; P=0.002), and increased ECV (30.4 ± 3.6% vs. 26.2 ± 2.9%; P<0.001). On multivariable Cox regression adjusted for age, sex, and NT-proBNP, ejection fraction (HR per 5% decrease 1.46, 95% CI 1.11–1.92; P=0.007), presence of LGE (HR 2.08, 95% CI 1.06–4.10; P=0.03), and ECV (HR per 1% increase 1.15, 95% CI 1.04–1.29; P=0.01) independently predicted heart failure hospitalization.
Conclusions
In stable ambulatory patients with non-ischemic dilated cardiomyopathy and elevated NT-proBNP levels, CMR-derived measures of ventricular function and tissue characterization provide strong predictive value for heart failure hospitalization. Ejection fraction, presence of LGE, and ECV were identified as the most important predictors, supporting the role of serial CMR in the stratification and management of this high-risk population.