PVDOMICS has the goal of understanding pulmonary vascular disease (PVD) across traditional WSPH Groups, including clinical and OMIC determinants of PVD severity and of RV compensation/failure. Although RV compensation to afterload is heterogeneous in Group 1, it is not known if similar phenotypes exist across Groups. The aim of this analysis is to compare global RV function relative to afterload (mPAP, mean pulmonary artery pressure or PVR, pulmonary vascular resistance) across WSPH Groups.
Patients (N= 155) at risk for PVD who enrolled in PVDOMICS underwent comprehensive evaluation including right heart catheterization, echocardiography, MRI, blood draws for OMICS, and adjudicated classification into WSPH Groups. Relationship between severity of PH and degree of RV dysfunction was assessed across groups. RV strain was analyzed using vector velocity imaging, Siemens Health©. RV ejection fraction (RVEF) was analyzed with Circle Cardiovascular Imaging© post-processing software in a subset cohort (N=86) across all WSPH Groups 1-5 from University of Arizona was stratified based on median mPAP (35mmHg). Data are expressed as number/%.
RV strain demonstrated high sensitivity especially to low afterload across Groups (Figure 1A, PVR vs RV free wall strain) (R=0.45, P=0.001 for all Groups, R=0.56 Group1, R=0.12 Group 2, R=0.45 Group 3, and R=0.34 Group 4). With low mPAP, RVEF was preserved across groups (Figure 1B). However, when afterload is high, Groups 1 and Group 3 appear to have the lowest RVEF (P<0.05 vs. Groups 2 and 4). A low RVEF (<median 40%) was seen in 29/59.2%, 1/11.1%, 5/31.3%, 4/44.4% of Groups 1-4, respectively.
PVDOMICS holds promise to improve understanding of determinants of RV function in varying forms of PVD. RV strain appears to be particularly sensitive to RV dysfunction at low afterload across Groups. In Groups 1 and 3, RV dysfunction may be more prominent when afterload is high.