Valve prosthesis-patient mismatch: hemodynamic, echocardiographic and clinical consequences.

OBJECTIVES: The purpose is to evaluate in vivo at rest and under stress conditions hemodynamic performance of the small size St. Jude Medical Regent (SJMR) prosthetic valve in patients with a body surface area (BSA) of 1.8 ± 0.11 m(2) and to define the role of valve prosthesis- patient mismatch on left ventricular mass regression following aortic valve replacement.

METHODS: We evaluated 25 cases (12 males and 13 females, mean age 65.2 ± 8 years) of aortic valve replacement (17 mm SJMR in three cases and 19 mm SJMR in 22 cases). All the patients underwent at rest Doppler echocardiography before and after surgery and both basal and dobutamine stress echocardiography (DSE) at follow-up. The mean duration of follow-up was 41.3 ± 24 months.

RESULTS: A significant reduction in mean and peak transaortic gradients and peak transaortic velocity over time following valve replacement has been identified. After surgery, there was a significant increase of ejection fraction. DSE significantly increased heart rate, ejection fraction, peak transaortic gradient and peak transaortic velocity. All patients passed DSE without complication. Even if a significant mismatch was present in 76% of cases, the left ventricular mass decreased significantly from preoperative value of 278.7 ± 51.1 g to 181.5 ± 52.73 g, respectively.

CONCLUSION: Aortic valve replacement with 17 mm SJMR or 19 mm SJMR prostheses appear to provide satisfactory clinical and hemodynamic results at rest and under DSE, even in those patients with BSA of 1.8 ± 0.11 m(2) where it was not possible to enlarge the aortic annulus. Prosthesis-patient mismatch is not associated with lesser regression of left ventricular mass. Dobutamine stress echocardiography should be a useful and effective means for evaluating prosthesis hemodynamic aspects.