Abstract 1937: Relief of Chronic Pulmonary Regurgitation with Percutaneous Valve Implantation Acutely Improves Ventricular Performance But Not Exercise Capacity
Background: Pulmonary regurgitation (PR) is a common problem in patients with repaired congenital heart defects. Percutaneous pulmonary valve implantation (PPVI) is a unique model to study the effect of chronic volume overload on right ventricular (RV) function and its potential for recovery, without the confounding effect of cardiopulmonary bypass.
Methods: 16 patients (median age 21, 75% tetralogy of Fallot), with peak RV outflow tract velocity < 3.5m/s on echo and PR fraction > 35% on magnetic resonance imaging (MRI) were studied before and within 3 months of PPVI with tissue Doppler, MRI and cardiopulmonary exercise testing. Hemodynamics were recorded at the time of PPVI.
Results: Following PPVI, MRI showed a reduction in PR (41.2 ± 7.3 v. 4.3 ± 6.2%, p < 0.001), a fall in RV end diastolic volume (117.8 ± 33.1 v. 100.6 ± 32.3 mL/m2, p < 0.001) and an increase in effective RV stroke volume (34.5 ± 8.0 v. 43.9 ± 13.8 mL/m2, p = 0.01). RV end systolic volume and ejection fraction did not change. Left ventricular (LV) end diastolic volume (66.0 ± 18.5 v. 77.1 ± 40.1 mL/m2, p = 0.13), stroke volume (38.3 ± 11.5 v. 46.0 ± 10.5 mL/m2, p = 0.002) and ejection fraction (58.3 ± 8.1 v. 63.5 ± 5.4 mL/m2, p = 0.002) all increased. RV systolic pressure fell (51.3 ± 13.6 v. 42.0 ± 9.7mmHg, p = 0.003) but end diastolic pressure did not change at catheterisation. Pulmonary artery diastolic pressure rose (8.9 ± 11.9 v. 11.9 ± 5.0mmHg, p = 0.041). Tissue Doppler showed no change in systolic parameters but there was a significant increase in mitral E/Ea (9.0 ± 2.0 v. 11.4 ± 3.2, p = 0.006) suggesting an increase in left atrial pressure. Though patients reported a symptomatic improvement there was no change in objective exercise capacity.
Conclusion: The pattern of hemodynamic and volumetric changes in the RV is consistent with a reduction in preload following restoration of a competent pulmonary valve. The increased stroke volume suggests that the RV is, however, decompensated prior to intervention and shifts back to the compensatory limb of the Frank-Starling curve following PPVI. This has associated benefits for LV function and should encourage early intervention before RV function becomes irreversibly damaged. Further follow-up is required to study the potential for improvement in exercise capacity.