New insights into the hemodynamics of pulmonary homograft patients under stress echocardiography - The contribution of pressure recovery

Background: The importance of pulmonary artery pressure recovery (PR) in patients with Ross procedures in whom a homograft substitutes the resected pulmonary valve, is unknown. The aim of the study was to evaluate the occurrence and extent of PR in the pulmonary artery in 65 asymptomatic patients with pulmonary homograft after Ross surgery during rest and exercise. Methods: Stress echocardiography was performed in 65 pulmonary homograft patients and 31 controls with native pulmonary valves up to 75 watts (W). Right ventricular systolic pressure (RVSP), transvalvular flow, mean pressure gradient (P ), valve resistance and RV stroke work were determined in the exercise (max. 75 W) and recovery phases in increments of 25W each. Results: Pulmonary homografts demonstrated significantly elevated P compared to controls at all stages. When considering pressure recovery (absolute and relative PR at rest 3.8+/-1.8 mmHg, 42.6+/-7.2%, respectively) and transvalvular energy loss (EL; at rest 4.5+/-4.3 mmHg) the homograft hemodynamics reached the level of controls. In a subgroup of patients with tricuspid regurgitation, resting RVSP was the same in homograft patients and controls (21.3 +/- 6.1 vs. 20.4 +/- 6.3, p=0.62), despite significant different P values. Conclusions: Ross patients with pulmonary homograft showed systematically increased hemodynamic parameters compared to normal pulmonary valves. These differences were abolished when PR was considered for homograft patients. The equality of RVSP values at rest in both groups shows non-invasive evidence for PR in the pulmonary system after homograft implantation. Therefore, PR appears to be an important measure in calculating the actual hemodynamics in pulmonary homografts.