Native T1 time of right ventricular insertion points by cardiac magnetic resonance: relation with invasive haemodynamics and outcome in heart failure with preserved ejection fraction

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Increased afterload to the right ventricle (RV) has been shown to induce myocardial fibrosis at the RV insertion points (RVIPs). Such changes can be discrete but potentially detected by cardiac magnetic resonance (CMR) T1-mapping. Whether RVIP fibrosis is associated with prognosis in heart failure with preserved ejection fraction (HFpEF) is unknown. We prospectively investigated 167 consecutive HFpEF patients, a population frequently suffering from post-capillary pulmonary hypertension, who underwent CMR including T1-mapping. About 92.8% also underwent right heart catheterization for haemodynamic assessment.Native T1 times were 995 ± 73 ms at the anterior and 1040 ± 90 ms at the inferior RVIP. By Spearman's rank order testing, RVIP T1 times were significantly correlated with pulmonary artery pressure (mean PAP, r = 0.313 and 0.311 for anterior and inferior RVIP), pulmonary artery wedge pressure (r = 0.301 and 0.251) and right atrial pressure (r = 0.245 and 0.185; P for all <0.05). During a mean follow-up of 43.2 ± 22.6 months, 30 (18.0%) subjects died. By multivariable Cox regression, NTproBNP [Hazard ratio (HR) 2.105, 95% confidence interval (CI) 1.332-3.328; P = 0.001], systolic PAP (HR 1.618, 95% CI 1.175-2.230; P = 0.003), and native T1 time of the anterior RVIP (HR 1.659, 95% CI 1.125-2.445; P = 0.011) were significantly associated with outcome. Also, by Kaplan-Meier analysis, T1 times at the anterior RVIPs had a significant effect on survival (log-rank, P = 0.002). Interstitial expansion of the anterior RVIP as detected by CMR T1-mapping reflects haemodynamic alterations, and is independently related with prognosis in HFpEF.