Abstract
Background: We hypothesized that noninvasively measured right ventricular (RV) to pulmonary arterial (RV-PA) coupling would be abnormal in chronic pulmonary regurgitation (PR) even in the setting of normal RV ejection fraction, and that RV-PA coupling indices would have a better correlation with peak oxygen consumption (VO2) compared with RV systolic indices alone. Methods: This was a retrospective study of 129 adults (repaired tetralogy of Fallot [TOF] n = 84 and valvular pulmonic stenosis [VPS] with previous intervention n = 45) with ≥ moderate native PR and RV ejection fraction > 50%. The 84 TOF patients were propensity matched with 84 patients with normal echocardiogram (control); age 28 ± 7 years and male sex n = 39 (46%). RV-PA coupling was measured according to fractional area change (FAC)/RV systolic pressure (RVSP) and tricuspid annular plane systolic excursion (TAPSE)/RVSP. Results: RV systolic function indices were similar between TOF and control groups (FAC 43 ± 6% vs 41 ± 5% [P = 0.164] and TAPSE 22 ± 5 mm vs 24 ± 6 mm [P = 0.263]). However, RV-PA coupling was lower in the TOF group (FAC/RVSP 1.10 ± 0.29 vs 1.48 ± 0.22 [P < 0.001]; TAPSE/RVSP 0.51 ± 0.15 vs 0.78 ± 0.11 [P < 0.001]) because of higher RV afterload (RVSP 42 ± 3 mm Hg vs 31 ± 3 mm Hg [P = 0.012]). FAC/RVSP (r = 0.61; P < 0.001) and TAPSE/RVSP (r = 0.69; P < 0.001) correlated with peak VO2 especially in the patients with impaired exercise capacity whereas FAC and TAPSE were independent of peak VO2. Similar comparisons between VPS and control groups showed no difference in TAPSE and FAC between groups, but lower FAC/RVSP and TAPSE/RVSP in the VPS group. Conclusions: There is abnormal RV-PA coupling in chronic PR, and noninvasively measured RV-PA coupling might potentially be prognostic because of its correlation with exercise capacity. © 2019 Canadian Cardiovascular Society