Myocardial Fibrosis is Associated With Pulmonary Artery Pressure and Adverse Outcomes in Patients With Preserved Left Ventricular Systolic Function

Background: Elevated LV end diastolic pressure (LVEDP) leads to high pulmonary artery pressure (PAP) in type II pulmonary hypertension (PH) with preserved LV systolic function (pEF) through unclear mechanisms. Myocardial fibrosis (MF), quantifiable by cardiovascular magnetic resonance (CMR) extracellular volume fraction (ECV), is common in heart disease and predicts poor outcomes. Hypothesis: We sought to demonstrate an independent association of ECV with PAP as well as adverse outcomes in patients with pEF. Methods: 276 patients without infiltrative heart disease; type I, III, IV PH; or valvular disease, underwent clinical 1.5T CMR and echocardiogram (TTE) within 7 days. 193 patients had pEF (EFu003e40%), with 55 undergoing catheterization (RHC). ECV was determined as previously described. Events were defined as death or heart failure admission. Results: Median TTE PAP was 33mmHg (range: 10-68); median ECV was 29.5% (range: 19-44). Univariable analysis showed modest correlation of ECV with TTE PAP (R 2 =0.08, p 2 =0.13, p 2 =0.30, p=0.01). Multivariable stepwise regression in pEF identified ECV, E/e’, left atrial volume index, RV size to be predictive of TTE PAP (R 2 =0.34, p=0.01). ECV did not correlate with PAP among those with EF Survival analysis of pEF cohort demonstrated worse outcomes in patients with ECV u003e median (Figure 1, log-rank p Conclusions: In a type II PH enriched cohort, ECV independently associated with PAP as well as outcomes in patients with pEF after adjustment for relevant confounders. This observation suggests that MF may affect LVEDP and subsequent PAP elevations, thus leading to adverse outcomes.