Abstract 16938: Serial Phase-Contrast MRI for Prediction of Pulmonary Haemodynamic Changes in Patients with Pulmonary Arterial Hypertension
Introduction: In pulmonary arterial hypertension (PAH), changes over time in pulmonary artery (PA) pressures and pulmonary vascular resistance (PVR) represent the best-established indicators of disease course. Accurate non-invasive evaluation of serial pulmonary hemodynamics would be desirable. Strong linear correlations of pulmonary hemodynamics with PA flow velocity and PA dimensions have been previously demonstrated using phase-contrast magnetic resonance imaging (PC-MRI).
Hypothesis: Changes in flow velocity and cross-sectional dimensions of the main PA as defined by serial PC-MRI can characterize temporal variations in invasive pulmonary hemodynamics evaluated by right heart catheterization (RHC).
Methods: The study was conducted in 20 patients with PAH and RHC and PC-MRI performed at baseline and after 11±5 months (range, 6–18 months). From PC-MRI the following parameters were derived: peak and average PA velocities; and maximum, minimum and average PA areas. Changes observed at follow-up (Δ) were correlated with Δ mean PA pressure, Δ systolic PA pressure and Δ PVR index at follow-up RHC. The diagnostic ability of PC-MRI to identify hemodynamic improvement (follow-up reduction in mean PA pressure >10 mmHg) was evaluated by ROC curve analysis.
Results: Overall, Δ PA areas significantly correlated with Δ mean PA pressure (r ≥ 0.61, p < 0.01 for all), Δ systolic PA pressure (r ≥ 0.68, p < 0.01 for all) and Δ PVR index (r ≥ 0.40, p < 0.05 for all). Δ peak PA velocity showed a significant negative correlation with Δ PVR index (r = −0.43, p < 0.01) only. PC-MRI showed good ability to identify patients with haemodynamic improvement by using Δ average PA velocity (sensitivity, 75% specificity, 92%) and Δ PA areas (sensitivity, 75–88%, specificity, 77–92%).
Conclusions: Variations in PA flow velocity and cross-sectional areas on serial PC-MRI significantly correlate with changes over time in pulmonary hemodynamics. PC-MRI shows a good diagnostic accuracy in the identification of patients with significant reduction in mean PA pressure at follow-up.
- © 2010 by American Heart Association, Inc.