RESUMEN
BACKGROUND: In patients with a small aortic root, the use of 19-mm valve prostheses for valve replacement is controversial because of the small orifice area of these valves. METHODS: To assess stress hemodynamics in patients with 19-mm valve prostheses, to find predictors of unfavorable hemodynamics, and to document the long-term follow-up, we examined 30 patients (age, 64 +/- 19 years; 27 women and 3 men; follow-up, 38 +/- 50 months) clinically and with the use of dobutamine stress echocardiography. A history was taken, and a physical examination was performed. At rest and during dobutamine stress, Doppler echocardiography was performed. RESULTS: At rest, transprosthetic gradients were moderately elevated with mean and peak gradients of 15 +/- 7 and 32 +/- 14 mmHg, and effective orifice areas were small (0.91 +/- 0.31 cm(2)). Gradients rose markedly during stress (mean, 37 +/- 14 mmHg; peak, 83 +/- 41 mmHg). Predictors of high transprosthetic gradients were larger body surface area, younger age, and valve type. Mean and peak gradients were lower with St. Jude Medical Hemodynamic Plus valves than with standard St. Jude Medical (P < 0.05) and other valves, and the effective orifice area was highest (1.07 +/- 0.29 cm(2); P < 0.05 versus standard St. Jude Medical) in this valve model. Sixty percent of patients developed significant dynamic subvalvular or intraventricular gradients (84 +/- 41 mmHg) during dobutamine stress. CONCLUSIONS: After aortic valve replacement with 19-mm prostheses in patients with a small aortic root, dobutamine stress leads to high transvalvular gradients, which are dependent on valve model, age, and body surface area. In addition, 60% of patients develop significant dynamic outflow obstructions. These findings and the persistence of some degree of exercise-induced symptoms in 70% of patients suggest that alternative surgical techniques should be considered if the size of the aortic annulus demands a 19-mm valve, especially if the patient seeks physical activity, is young, or is of larger body size.