Serial pulmonary vascular resistance assessment in patients late after ventricular septal defect repair

The long-term evolution of pulmonary vascular resistance (PVR) after ventricular septal defect (VSD) repair is unknown. This study serially evaluated resting and exercise PVR after VSD repair in childhood.

Patients were enrolled from the outpatient Adult Congenital Heart Disease clinic of the University Hospitals Leuven and compared to age- and gender-matched controls. Participants underwent resting and exercise echocardiography and cardiopulmonary exercise testing at baseline and follow-up. Total PVR was calculated as the ratio of mean pulmonary artery pressure (mPAP) to cardiac output (CO). The slope of the mPAP-CO curve (exercise PVR) was obtained using linear regression analysis.

Twenty-seven patients (mean age 31 ± 7 years, 70% male) and 18 controls were included. At baseline, patients had larger right ventricular (RV) end-diastolic areas (10 ± 2 vs 9 ± 1 cm²/m², p = 0.001) and lower tricuspid annular plane systolic excursion (TAPSE) (17 (17-19) vs 26 (22-28) mm, p < 0.001). After 1.1 (1.0-1.5) years follow-up, similar differences in RV areas and TAPSE were found. Patients reached lower peak workload and cardiac index compared to controls at each time point. Peak total PVR was higher (Baseline: 2.7 ± 0.8 vs 2.2 ± 0.3 mm Hg/L/min, p = 0.005; Follow-up: 2.9 ± 0.9 vs 2.1 ± 0.3 mm Hg/L/min, p < 0.001) and the mPAP-CO slope was steeper (Baseline: 2.2 ± 0.8 vs 1.7 ± 0.3 mm Hg/L/min, p = 0.008; Follow-up: 2.5 ± 0.9 vs 1.6 ± 0.3 mm Hg/L/min, p < 0.001) in patients. The mPAP-CO slope in patients correlated inversely with peak oxygen uptake (R = -0.41 and - 0.45, p = 0.036 and 0.022, baseline and follow-up, respectively).

Despite repair, VSD patients seem to show altered pulmonary hemodynamics and RV impairment at rest and exercise, supporting life-long follow-up.