Background: Vasodilator therapy with nifedipine reduces left ventricular volume and mass and increases the ejection fraction in asymptomatic patients with severe aortic regurgitation.
Methods: To assess whether vasodilator therapy reduces or delays the need for valve replacement, we randomly assigned 143 asymptomatic patients with isolated, severe aortic regurgitation and normal left ventricular systolic function to receive either nifedipine (20 mg twice daily, 69 patients) or digoxin (0.25 mg daily, 74 patients).
Results: By actuarial analysis, we determined that after six years a mean (+/- SD) of 34 +/- 6 percent of the patients in the digoxin group had undergone valve replacement, as compared with only 15 +/- 3 percent of those in the nifedipine group (P < 0.001). In the digoxin group, valve replacement (in a total of 20 patients) was performed because of left ventricular dysfunction (ejection fraction < 50 percent) in 75 percent, left ventricular dysfunction plus symptoms in 10 percent, and symptoms alone in 15 percent. In the nifedipine group, all six patients who underwent valve replacement did so because of the development of left ventricular dysfunction. In addition, all the patients in both groups who underwent aortic-valve replacement had an increase of 15 percent or more in the left ventricular end-diastolic volume index. After aortic-valve replacement, 12 of the 16 patients (75 percent) in the digoxin group and all six patients in the nifedipine group who had had an abnormal left ventricular ejection fraction before surgery had a normal ejection fraction.
Conclusions: Long-term vasodilator therapy with nifedipine reduces or delays the need for aortic-valve replacement in asymptomatic patients with severe aortic regurgitation and normal left ventricular systolic function.