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Background: The aims of this study were to investigate the evolution of the transprosthetic pressure gradient and effective orifice area (EOA) during dynamic bicycle exercise in bileaflet mechanical heart valves and to explore the relationship with exercise capacity., Methods: Patients with bileaflet aortic valve replacement (n = 23) and mitral valve replacement (MVR; n = 16) prospectively underwent symptom-limited supine bicycle exercise testing with Doppler echocardiography and respiratory gas analysis. Transprosthetic flow rate, peak and mean transprosthetic gradient, EOA, and systolic pulmonary artery pressure were assessed at different stages of exercise., Results: EOA at rest, midexercise, and peak exercise was 1.66 ± 0.23, 1.56 ± 0.30, and 1.61 ± 0.28 cm 2 , respectively (P = .004), in aortic valve replacement patients and 1.40 ± 0.21, 1.46 ± 0.27, and 1.48 ± 0.25 cm 2 , respectively (P = .160), in MVR patients. During exercise, the mean transprosthetic gradient and the square of transprosthetic flow rate were strongly correlated (r = 0.65 [P < .001] and r = 0.84 [P < .001] for aortic valve replacement and MVR, respectively), conforming to fundamental hydraulic principles for fixed orifices. Indexed EOA at rest was correlated with exercise capacity in MVR patients only (Spearman ρ = 0.68, P = .004). In the latter group, systolic pulmonary artery pressures during exercise were strongly correlated with the peak transmitral gradient (ρ = 0.72, P < .001)., Conclusions: In bileaflet mechanical valve prostheses, there is no clinically relevant increase in EOA during dynamic exercise. Transprosthetic gradients during exercise closely adhere to the fundamental pressure-flow relationship. Indexed EOA at rest is a strong predictor of exercise capacity in MVR patients. This should be taken into account in therapeutic decision making and prosthesis selection in young and dynamic patients., (Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Objectives: Restrictive mitral valve annuloplasty combined with coronary artery bypass grafting is the treatment of choice for ischemic mitral regurgitation. Postoperative functional mitral stenosis and its potential impact on functional capacity remain the object of debate. The aim of this study was to assess functional and hemodynamic outcome at rest and during exercise in a population with ischemic mitral regurgitation after a standardized restrictive mitral valve annuloplasty., Methods: A total of 23 patients with ischemic mitral regurgitation who were previously treated with coronary artery bypass grafting and restrictive mitral valve annuloplasty underwent a semi-supine (bicycle) exercise test with Doppler echocardiography and ergospirometry. The surgical technique was identical in all patients, using a complete semi-rigid ring downsized by 2 sizes after measuring the height of the anterior mitral leaflet, to achieve a coaptation length of at least 8 mm., Results: At a mean follow-up of 28 ± 15 months, mean transmitral gradients at rest and maximal exercise were 4.4 ± 1.8 mm Hg and 8.2 ± 4.2 mm Hg, respectively (P < .001). Transmitral gradients did not correlate with exercise capacity (maximal oxygen uptake) or pulmonary artery pressures. Patients with a resting mean gradient of 5 mm Hg or greater (n = 9) reached a significantly higher maximal oxygen uptake; however, they had a better ejection fraction and cardiac output at rest and reached a higher cardiac output at peak exercise., Conclusions: Transmitral gradients after restrictive mitral valve annuloplasty for ischemic mitral regurgitation did not correlate with functional capacity as measured by maximal oxygen uptake during semi-supine bicycle testing. Functional capacity and transmitral gradients are determined not only by the severity of mitral stenosis but also by hemodynamic factors, such as ejection fraction and cardiac output. Transmitral gradients should be interpreted with respect to patient hemodynamics and not necessarily be considered as detrimental for functional capacity., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)