Background: The mechanisms underlying the high interindividual variability demonstrated for right-ventricular (RV) adaptation to exercise have not yet been identified, but different pulmonary vascular adaptations among individuals could be involved. Pulmonary transit of agitated saline (PTAS) during exercise has been demonstrated to be a good estimator of vascular reserve.
Aim: The aim of this study was to evaluate the presence of PTAS among endurance athletes (EAs) of both sexes and its influence on RV adaptation to exercise.
Methods: A total of 100 highly trained EAs performed a maximal cardiopulmonary exercise test. Bi-ventricular functional and structural characteristics as well as PTAS were evaluated at baseline and at peak exercise. Athletes were distributed between two groups based on the amount of PTAS during exercise as high (HTPAS; >12 bubbles) and low (LPTAS; ≤12 bubbles).
Results: Overall, 11 EAs exhibited an intra-cardiac shunt at rest and 1 met the criteria for chronic pulmonary disease and were excluded from the study. Among the remaining 88 EAs (51% women), 47 (53%) athletes were classified as HPTAS and 41 (47%) as LPTAS. HPTAS capability was associated with significantly larger RV contractile reserve, larger pulmonary vascular reserve and an enhanced maximal exercise capacity. On multivariate analysis, females were the only independent correlate of the HPTAS capability.
Conclusion: In highly trained endurance athletes, a HPTAS capability during exercise corresponded to an increase in pulmonary vascular and RV contractile reserves as well as an enhanced maximal exercise capacity. The long-term clinical or performance implications of the absence or presence of pulmonary shunting, and the subsequent RV afterload increase while performing exercise, remains to be determined.
Keywords: Pulmonary circulation; contrast echocardiography; exercise echocardiography; right-ventricle.