Usefulness of Cardiovascular Magnetic Resonance Indices to Rule In or Rule Out Precapillary Pulmonary Hypertension

Abstract

Background: Various cardiovascular magnetic resonance (CMR) imaging indices are used to assess pulmonary hypertension (PH; mean pulmonary artery pressure >= 25 mm Hg). We compared the value of CMR indices to diagnose precapillary PH in treatment-naive patients evaluated for the first time for known or suspected pulmonary vascular disease. Methods: Right heart catheterization and CMR were performed within 48 hours of each other in 85 consecutive subjects. The tricuspid annular plane systolic excursion, right ventricular (RV) fractional area change (RVFAC), RV ejection fraction, systolic eccentricity index, and RV end-diastolic area over left ventricular end-diastolic area ratio were calculated. The pulmonary artery trunk diameter, main pulmonary artery relative area change, and mean flow velocity were also calculated. Results: There were 20 non-PH subjects (14 women/6 men, 55 +/- 14 years of age, mean pulmonary artery pressure [mPAP] = 20 +/- 4 mm Hg) and 65 precapillary PH subjects (32 women/33 men, 60 +/- 15 years of age; P = not significant; mPAP = 46 +/- 12 mm Hg; 54% with chronic thromboembolic PH). All CMR indices showed essentially the same (good) value to rule in precapillary PH. The RV end-diastolic area over left ventricular end-diastolic area ratio and RVFAC, which are relatively easy to measure, had a large area under the receiver operating characteristic curve (0.93, with optimal cut-off > 0.96, and 0.92, with optimal cut-off <= 35%, respectively), not significantly different from RV ejection fraction. In addition, RVFAC > 45% was documented in none of 65 PH and in 10 of 20 non-PH; thus, in a population similar to ours, RVFAC measurement could potentially have avoided unnecessary catheterization in 50% of non-PH subjects. Conclusions: In treatment-naive subjects in whom pulmonary vascular disease is highly suspected, right-sided CMR indices distinguish between PH and non-PH patients. RVFAC might have particular value in excluding precapillary PH.