Cardiovascular magnetic resonance 4D flow analysis has a higher diagnostic yield than Doppler echocardiography for detecting increased pulmonary artery pressure

Abstract

Background: Pulmonary hypertension is definitively diagnosed by the measurement of mean pulmonary artery (PA) pressure (mPAP) using right heart catheterization. Cardiovascular magnetic resonance (CMR) four-dimensional (4D) flow analysis can estimate mPAP from blood flow vortex duration in the PA, with excellent results. Moreover, the peak systolic tricuspid regurgitation (TR) pressure gradient (TRPG) measured by Doppler echocardiography is commonly used in clinical routine to estimate systolic PA pressure. This study aimed to compare CMR and echocardiography with regards to quantitative and categorical agreement, and diagnostic yield for detecting increased PA pressure. Methods: Consecutive clinically referred patients (n = 60, median [interquartile range] age 60 [48-68] years, 33% female) underwent echocardiography and CMR at 1.5 T (n = 43) or 3 T (n = 17). PA vortex duration was used to estimate mPAP using a commercially available time-resolved multiple 2D slice phase contrast three-directional velocity encoded sequence covering the main PA. Transthoracic Doppler echocardiography was performed to measure TR and derive TRPG. Diagnostic yield was defined as the fraction of cases in which CMR or echocardiography detected an increased PA pressure, defined as vortex duration ≥15% of the cardiac cycle (mPAP ≥25 mmHg) or TR velocity > 2.8 m/s (TRPG > 31 mmHg). Results: Both CMR and echocardiography showed normal PA pressure in 39/60 (65%) patients and increased PA pressure in 9/60 (15%) patients, overall agreement in 48/60 (80%) patients, kappa 0.49 (95% confidence interval 0.27-0.71). CMR had a higher diagnostic yield for detecting increased PA pressure compared to echocardiography (21/60 (35%) vs 9/60 (15%), p < 0.001). In cases with both an observable PA vortex and measurable TR velocity (34/ 60, 56%), TRPG was correlated with mPAP (R 2 = 0.65, p < 0.001).

Cardiac Magnetic Resonance Imaging in Pulmonary Arterial Hypertension: Ready for Clinical Practice and Guidelines?

“…A more recent, and direct, method for estimating MPAP by CMR assesses the presence and duration of vortical blood flow in the main PA (Table 1 ) [ 81 ••, 82 – 85 ]. A vortex is a formation of concentric ring- or spiral-shaped curves [ 86 – 89 ] and is an effect of coexisting forward flow and retrograde flow at the posterior wall during systole in the main PA (Fig.…”

“…A vortex is a formation of concentric ring- or spiral-shaped curves [ 86 – 89 ] and is an effect of coexisting forward flow and retrograde flow at the posterior wall during systole in the main PA (Fig. 1(N) ) [ 81 ••, 82 – 85 ]. The premises for estimating MPAP from vortex formation are (1) detection of a vortex (indicating increased resistance and decreased elastance) and (2) the time it exists in relation to the full cardiac phase (to evaluate the pressure increase).…”

The heart as a spring, the measurement of myocardial bounce to assess left ventricular function on cardiac MR

“…Very little has been written about the use of cardiac MR to evaluate left diastolic function. Recently, Ramos et al [23,24] concluded good agreement and diagnostic yield for pulmonary hypertension and diastolic dysfunction between cardiac MR and echocardiography. This contributes to expanding the diagnostic capabilities of cardiac MR in patients with cardiac dysfunction.…”

Quantification of Vortex Flow in Pulmonary Arteries of Patients With Chronic Thromboembolic Pulmonary Hypertension

“…However, it is not possible to calculate the absolute blood pressure solely from a velocity field. Previous studies have investigated the relationship between mean PAP and velocity field [7,19,20,21]. 3D structure and coexists with helical flow, it is difficult to accurately make a visual assessment of changes in its size and duration.…”

“…Reiter et al (2015)[10] observed vortices in the pulmonary trunk for patients with pulmonary hypertension, and successfully demonstrated a strong correlation between appearance time of vortices and mean PAP. Using the same technique, Ramos et al(2020)[21] demonstrated a correlation between mean PAP, estimated by the duration, and the transtricuspid pressure gradient (TRPG). Because vortical flow in the PA has a…”