Background: The underlying pathophysiology of heart failure with preserved ejection fraction (HFPEF) is incompletely understood, but myocardial extracellular matrix accumulation is thought to play a major role. Our aims were to estimate myocardial extracellular matrix using cardiac magnetic resonance T1 mapping and to assess the relationship between pathobiology/pathophysiology and prognosis.
Methods and results: Patients with suspected HFPEF (n=100) were enrolled in this prospective, observational study. Confirmatory diagnostic tests, cardiac magnetic resonance imaging including T1 mapping, and invasive hemodynamic assessments were performed at baseline. Sixty-one patients with confirmed HFPEF entered a longitudinal outcome-monitoring phase (mean, 22.9±5.0 months), during which 16 had a cardiac event. Cardiac magnetic resonance T1 time (hazard ratio, 0.99; 95% confidence interval, 0.98-0.99; P=0.046), left atrial area (hazard ratio, 1.08; 95% confidence interval, 1.03-1.13; P<0.01), and pulmonary vascular resistance (hazard ratio, 1.01; 95% confidence interval, 1.00-1.01; P=0.03) were significantly associated with cardiac events. Patients with T1 times below the median (<388.3 ms) were at greater risk of cardiac events than the rest of the group (P<0.01). Extracellular matrix of left ventricular biopsies (n=9), quantified by TissueFAXS technology correlated with T1 time (R=0.98; P<0.01). T1 time also correlated with right ventricular-pulmonary arterial coupling (pulmonary vascular resistance: R=-0.36; P<0.01; right ventricular ejection fraction: R=0.28; P=0.01).
Conclusions: In the present preliminary study, cardiac magnetic resonance postcontrast T1 time is associated with prognosis in HFPEF, suggesting postcontrast T1 as possible biomarker for HFPEF.
Keywords: hypertension, pulmonary; magnetic resonance imaging; prognosis.