Abstract
Abstract only
Introduction:
An abnormal right ventricular (RV) end-diastolic pressure-volume relationship (EDPVR) is an early marker of poor prognosis in pulmonary arterial hypertension (PAH). Prior studies assessing RV diastolic impairment utilized pressure (P) measured at right heart catheterization (RHC) and non-simultaneous volume (V) measured by cardiac magnetic resonance imaging (cMRI), which serves as the current reference standard for V. Our aims were: (a) to validate a single-beat (SB) method to assess RV EDPVR in an animal model against multi-beat (MB) measurements during preload variation, and (b) to use V obtained via transthoracic 3D echocardiography (3DE) during simultaneous RHC.
Methods:
In six anesthetized swine under an Institutional Animal Care & Use Committee-approved protocol, a SB method was used to derive EDPVR as V
15
, the previously described predicted ventricular V at a theoretical EDP of 15 mmHg. A multi-beat (MB) reference EDPVR was defined using conductance/micromanometer catheter-measured RVP and V during preload variation. The V
15
value derived from the SB method was compared by Bland-Altman analysis to that defined by the reference EDPVR. Clinically, the SB method was applied to 13 patients with PAH and 10 age- and gender-matched controls who underwent RHC with simultaneous transthoracic 3DE. V
15
values between groups were compared by t-test.
Results:
In the animal model there was strong correlation between MB and SB estimates of V
15
(r=0.95; p<0.0001) with acceptable accuracy and precision (bias -4.2±6.1 mL, overall error 8.4%). Consistent with previous reports using cMRI, PAH patients exhibited greater V
15
(166±43 mL vs. 131±30 mL; p=0.04)
(Figure 1)
.
Conclusion:
This study demonstrates validity of a SB assessment of RV EDPVR using data obtained from transthoracic 3DE performed during RHC, obviating the need for non-simultaneous cMRI. Further studies are needed to examine SB assessment of RV EDPVR across the spectrum of PH phenotypes.