Evaluation of St. Jude Medical mitral valve function by exercise Doppler echocardiography

The aim of this study was to detect borderline mitral valve dysfunction in 100 asymptomatic patients with a St. Jude Medical valve. We studied rest and exercise hemodynamics by Doppler echocardiography. Study patients were divided into two groups according to the time since surgery: group A had valves implanted less than 5 years ago (44 patients), group B had valves implanted more than 5 years ago (56 patients). Although patients had no clinical signs of valve dysfunction, group B was found to have significant reduction of mitral valve area (p < 0.05). In the group A patients, mean gradients at rest increased from 4 +/- 2, 4 +/- 2, and 3 +/- 1 mmHg in valve sizes of 25, 27, and 29 mm, respectively, to 7 +/- 2, 7 +/- 3, and 5 +/- 2 mmHg with exercise. In the group B patients, mean gradients at rest increased from 7 +/- 1, 6 +/- 2, and 5 +/- 1 mmHg to 14 +/- 3, 13 +/- 3, and 10 +/- 4 mmHg, respectively, after exercise. The percent increase (mean) in peak pressure gradient with exercise was significantly higher in group B (more than 100%) than in group A (less than 80%) (p < 0.01). The percent increase in mean gradient with exercise was also significantly higher in group B (more than 100%) than in group A (less than 75%). In conclusion, patients with reduced valve area and more than a 100% increase of peak and mean gradients should be followed up carefully. If any signs or symptoms of heart failure develop, they must be considered as candidates for surgery.