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 pulmonary regurgitation.
Methods: Patients with ≥ moderate pulmonary regurgitation in our clinic, 2003–2015, were identified, and those with and without CMRI were enrolled into the study cohort and validation cohort respectively. Endpoint was to determine the association between echocardiographic indices of RV-PA coupling (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 history of atrial and/or ventricular arrhythmia)
Results: Of the 256 patients in the study cohort (age 33±6 years), 187 (73%) had tetralogy of Fallot while 69 (25%) had valvular pulmonic stenosis. TAPSE/RVSP (r=0.73, p<0.001) and FAC/RVSP (r=0.78, p<0.001) 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<0.001). These RV-PA coupling indices were tested in a validation cohort of 218 patients (age 37±9 years). Similar to the observation in the study cohort, TAPSE/RVSP (r=0.59, p<0.001) and FAC/RVSP (r=0.70, p<0.001) correlated with peak VO2.
Conclusion: Echocardiographic indices of RV-PA coupling were comparable to RVESVI in predicting exercise capacity in patients with pulmonary regurgitation, and may be important in the assessment of patients with contraindications to CMRI.