Qualification of Ventricular Flow in Patients With Precapillary Pulmonary Hypertension With 4-dimensional Flow Magnetic Resonance Imaging

Abstract

Purpose: Our goal was to study both right and left ventricular blood flow in patients with precapillary pulmonary hypertension (pre-PH) with 4-dimensional (4D) flow magnetic resonance imaging (MRI) and to analyze their correlation with cardiac functional metrics on cardiovascular magnetic resonance (CMR) and hemodynamics from right heart catheterization (RHC).

Materials and methods: 129 patients (64 females, mean age 47 ± 13 y) including 105 patients with pre-PH (54 females, mean age 49 ± 13 y) and 24 patients without PH (10 females, mean age 40 ± 12 y) were retrospectively included. All patients underwent CMR and RHC within 48 hours. 4D flow MRI was acquired using a 3-dimensional retrospectively electrocardiograph-triggered, navigator-gated phase contrast sequence. Right and left ventricular flow components including the percentages of direct flow (PDF), retained inflow (PRI), delayed ejection flow (PDE), and residual volume (PRVo) were respectively quantified. The ventricular flow components between patients with pre-PH and non-PH were compared and correlations of flow components with CMR functional metrics and hemodynamics measured with RHC were analyzed. Biventricular flow components were compared between survivors and deceased patients during the perioperative period.

Results: Right ventricular (RV) PDF and PDE significantly correlated with RVEDV and RV ejection fraction. RV PDF negatively correlated with pulmonary arterial pressure (PAP) and pulmonary vascular resistance. When the RV PDF was <11%, the sensitivity and specificity of RV PDF for predicting mean PAP ≥25 mm Hg were 88.6% and 98.7%, respectively, with an area under the curve value of 0.95 ± 0.02. When RV PRVo was more than 42%, the sensitivity and specificity of RV PRVo for predicting mean PAP ≥25 mm Hg were 85.7% and 98.5%, respectively, with an area under the curve value of 0.95 ± 0.01. Nine patients died during the perioperative period. Biventricular PDF, RV PDE, and PRI of survivors were higher than nonsurvivors whereas RV PRVo increased in deceased patients.

Conclusions: Biventricular flow analysis with 4D flow MRI provides comprehensive information about the severity and cardiac remodeling of PH and may be a predictor of perioperative death of patients with pre-PH.

Keywords: 4-dimensional flow; function; hemodynamics; magnetic resonance imaging; precapillary pulmonary hypertension.

FIGURE 1

A flowchart detailing how participants were selected.

FIGURE 2

A, LV flow component illustration. B, RV blood flow component illustration. DF represented by green; RI, yellow; DE, blue; RVo, red.

FIGURE 3

Visualization of LV and RV flow in a female patient with CTEPH (MPAP = 44 mm Hg and PVR = 1200 dyne.s.cm⁵). A, Pathline visualization of the LV flow components (DF, RI, DE flow, and residual volume) in systole. B, Pathline visualization of the LV flow components (DF, RI, DE flow, and residual volume) in diastole. C, Pathline visualization of the RV flow components (DF, RI, DE flow, and residual volume) in systole. D, Pathline visualization of the RV flow components (DF, RI, DE flow, and residual volume) in diastole. Ao indicates aorta; LA, left atrium; LVOT, left ventricular outflow tract; PA, pulmonary artery; RA, right atrium; RVOD, RV outflow tract.

FIGURE 4

Visualization of left and RV flow in a male patient with chronic thromboembolism (MPAP = 16 mm Hg, PVR = 160 dyne.s.cm⁵). A, Pathline visualization of the LV flow components (DF, RI, DE flow, and residual volume) in systole, B, Pathline visualization of the LV flow components (DF, RI, DE flow, and residual volume) in diastole. C, Pathline visualization of the RV flow components (DF, RI, DE flow, and residual volume) in systole. D, Pathline visualization of the RV flow components (DF, RI, DE flow, and residual volume) in diastole. Ao indicates aorta; LA, left atrium; LVOT, left ventricular outflow tract; PA, pulmonary artery; RA, right atrium; RVOD, RV outflow tract.

FIGURE 5

Correlations of RV flow components with NT-proBNP. A, RV-PDF negatively correlates with NT-proBNP. B, RV-PDE negatively correlates with NT-proBNP. C, RV-PRI negatively correlates with NT-proBNP. D, RV-PRVo positively correlates with NT-proBNP.

FIGURE 6

The ROC of the ability of RV-PDF (A) and RV-PRVo (B) to detect MPAP ≥25 mm Hg. A, When RV-PDF is <11%, the sensitivity and specificity of RV-PDF for predicting PH (MPAP ≥25 mm Hg) respectively are 88.6% and 98.7% with an area under ROC value of 0.95 ± 0.02. B, When RV-PRVo is more than 42%, its sensitivity and specificity for predicting PH (MPAP ≥25 mm Hg) respectively were 85.7% and 98.5% with an area under the curve value of 0.95 ± 0.01. AUC indicates area under the curve.