Right ventricular and pulmonary vascular function indices for risk stratification of patients with pulmonary regurgitation

Background: We hypothesized that echocardiographic indices of right ventricular to pulmonary artery (RV-PA) coupling were comparable to cardiac magnetic resonance imaging (CMRI)-derived RV volumetric indices in predicting disease severity in chronic pulmonary regurgitation (PR). Methods: Patients with ≥ moderate PR (2003-2015) with and without prior CMRI scans were enrolled into the study cohort and validation cohort, respectively. Endpoint was to determine the association between noninvasive RV-PA coupling indices (tricuspid annular plane systolic excursion/right ventricular systolic pressure [TAPSE/RVSP] and fractional area change [FAC]/RVSP ratio) and markers of disease severity, and compared this association to that of CMRI-derived RV volumetric indices and markers of disease severity (peak oxygen consumption [VO₂], NT-proBNP and atrial and/or ventricular arrhythmias). Results: Of the 256 patients in the study cohort (age 33 ± 6 years), 187 (73%) had tetralogy of Fallot (TOF) while 69 (27%) had valvular pulmonic stenosis (VPS). TAPSE/RVSP (r = 0.73, P <.001) and FAC/RVSP (r = 0.78, P <.001) correlated with peak VO₂. Among the CMRI-derived RV volumetric indices analyzed, only right ventricular end-systolic volume index correlated with peak VO₂ (r = −0.54, P <.001) and NT-proBNP (r = 0.51, P <.001). These RV-PA coupling indices were tested in the validation cohort of 218 patients (age 37 ± 9 years). Similar to the study cohort, TAPSE/RVSP (r = 0.59, P <.001) and FAC/RVSP (r = 0.70, P <.001) correlated with peak VO₂. TAPSE/RVSP (but not FAC/RVSP) was also associated with arrhythmia occurrence in both the study cohort and validation cohorts. Conclusion: Noninvasive RV-PA coupling may provide complementary prognostic data in the management of chronic PR. Further studies are required to explore this clinical tool.