Abstract
ObjectivesLongitudinal hemodynamic follow-up is important in the management of pulmonary hypertension (PH). This study aimed to evaluate the potential of MR 4-dimensional (4D) flow imaging to predict changes in the mean pulmonary arterial pressure (mPAP) during serial investigations.MethodsForty-four adult patients with PH or at risk of developing PH repeatedly underwent routine right heart catheterization (RHC) and near-term MR 4D flow imaging of the main pulmonary artery. The duration of vortical blood flow along the main pulmonary artery was evaluated from MR 4D velocity fields using prototype software and converted to an MR 4D flow imaging-based mPAP estimate (mPAPMR) by a previously established model. The relationship of differences between RHC-derived baseline and follow-up mPAP values (ΔmPAP) to corresponding differences in mPAPMR (ΔmPAPMR) was analyzed by means of regression and Bland-Altman analysis; the diagnostic performance of ΔmPAPMR in predicting mPAP increases or decreases was investigated by ROC analysis.ResultsAreas under the curve for the prediction of mPAP increases and decreases were 0.92 and 0.93, respectively. With the natural cutoff ΔmPAPMR = 0 mmHg, mPAP increases (decreases) were predicted with an accuracy, sensitivity, and specificity of 91% (91%), 85% (89%), and 94% (92%), respectively. For patients in whom 4D flow allowed a point estimate of mPAP (mPAP > 16 mmHg), ΔmPAPMR correlated strongly with ΔmPAP (r = 0.91) and estimated ΔmPAP bias-free with a standard deviation of 5.1 mmHg.ConclusionsMR 4D flow imaging allows accurate non-invasive prediction and quantification of mPAP changes in adult patients with PH or at risk of developing PH.Trial registrationClinicalTrials.gov identifier: NCT00575692 and NCT01725763Key Points• MR 4D flow imaging allows accurate non-invasive prediction of mean pulmonary arterial pressure increases and decreases in adult patients with or at risk of developing pulmonary hypertension.• In adult patients with mean pulmonary arterial pressure > 16 mmHg, MR 4D flow imaging allows estimation of longitudinal mean pulmonary arterial pressure changes without bias with a standard deviation of 5.1 mmHg.
Highlights
Pulmonary hypertension (PH) is a progressive, heterogeneous, potentially life-shortening pathophysiological condition diagnosed invasively by right heart catheterization (RHC) as a mean pulmonary arterial pressure exceeding 20 mmHg at rest [1]
There are sparse reports of cases featuring changes in the appearance of vortical blood flow patterns in chronic thromboembolic PH after percutaneous transluminal pulmonary angioplasty [29] and pulmonary thromboendarterectomy [30], it remains unknown whether the observed pressure relationship of vortical blood flow in the main pulmonary artery persists during PH therapy and whether differences in the duration of vortical blood flow along the main pulmonary artery can predict mean pulmonary arterial pressure (mPAP) changes during treatment
PH was diagnosed by RHC in 28 of 44 patients: 16 subjects were classified as having PH due to pulmonary arterial hypertension (PAH), 2 subjects as having PH due to lung diseases, 7 subjects as having chronic thromboembolic PH (CTEPH), and 3 subjects as having PH secondary to multifactorial mechanisms
Summary
Pulmonary hypertension (PH) is a progressive, heterogeneous, potentially life-shortening pathophysiological condition diagnosed invasively by right heart catheterization (RHC) as a mean pulmonary arterial pressure (mPAP) exceeding 20 mmHg at rest [1]. Allowing for an accurate evaluation of cardiac function and morphology, various quantitative MRI parameters have been reported to be significantly altered in PH [7,8,9,10,11,12,13,14,15,16,17,18,19,20] including, among others, the appearance of vortical blood flow along the main pulmonary artery as assessed by time-resolved, three-directional MR phase contrast (4D flow) imaging [19, 21,22,23,24,25,26,27,28]. There are sparse reports of cases featuring changes in the appearance of vortical blood flow patterns in chronic thromboembolic PH after percutaneous transluminal pulmonary angioplasty [29] and pulmonary thromboendarterectomy [30], it remains unknown whether the observed pressure relationship of vortical blood flow in the main pulmonary artery persists during PH therapy and whether differences in the duration of vortical blood flow along the main pulmonary artery can predict mPAP changes during treatment
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