In patients with pulmonary hypertension (PH), right ventricle (RV) extracellular volume correlates significantly with noninvasive measures of pulmonary artery (PA) stiffness, according to research published in American Journal of Respiratory and Critical Care Medicine.

Researchers assessed the relationship between PA stiffness and RV fibrosis using noninvasive cardiac magnetic resonance imaging (cMRI) methods in patients with PH.

Study participants included 16 adult men and women from the Providence Veterans Affairs Medical Center in Providence, Rhode Island. Investigators conducted cMRI and used societal guidelines to quantify and analyze left ventricular (LV) and RV volumes, mass, and function, and PA pulse wave velocity (PWV) was measured.


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All patients in the cohort had PH, with mean pulmonary artery pressure (mPAP) ranging from 22 to 45 mm Hg with elevated pulmonary vascular resistance (PVR) (3.1 ± 1.3 Wood U). After cMRI, investigators noted that participants had preserved left ventricular ejection fraction (LVEF) (mean 58%±7%) and lower right ventricular ejection fraction (RVEF) (mean 46% ± 12%). Right ventricular hypertrophy was also frequent (RV mass 50.7 ± 16.7 g; median, 58 g).

Right ventricular extracellular volume was significantly correlated with PA PWV (0.73; P =.001) and was negatively correlated with PA relative area change (−0.69; P =.003); RV extracellular volume was not significantly correlated with age, body mass index, mPAP, PVR, LV or RV mass, LVEF, or RVEF.

Univariate regression analyses found that approximately half of the RV extracellular volume variance could be explained through measures of PA stiffness: 53% was by PA PWV and 47% was by PA relative area change.

Models adjusting for either age, body mass index, LVEF or RVEF, LV or RV mass, mPAP, or PVR found that these relationships remained “significant and unchanged or stronger.”

Study limitations included the small sample size, the recruitment of a referral population, and limited generalizability because of the older, almost entirely male population studied. Researchers also noted that because of the cross-sectional nature of the study, a causal relationship between RV fibrosis and PA stiffness could not be inferred.

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“Our study shows a relationship of RV fibrosis to PA stiffness on cMRI,” the researchers concluded. They added that “noninvasive assessment of RV fibrosis on cMR will allow further longitudinal exploration of the relationship of RV remodeling, central artery stiffening, and clinical outcomes in PH patients.”

Abbasi is an employee of Amgen, Inc. Please see the original reference for a full list of author’s disclosures.

Reference

Jankowich M, Abbasi SA, Vang A, Choudhary G. Right ventricular fibrosis is related to pulmonary artery stiffness in pulmonary hypertension: a cardiac magnetic resonance imaging study [published online May 30, 2019]. Am J Respir Crit Care Med. doi:10.1164/rccm.201903-0580LE