Background: In patients with aortic stenosis and a normal coronary angiogram, a coronary flow reserve (CFR) is impaired. The aim of the present study was to examine the effect of aortic valve replacement (AVR) on the CFR after a long-term follow-up.
Patients and methods: 30 patients with aortic stenosis and a normal coronary angiogram were enrolled in the study. CFR measurements were made on 21 patients 123 +/- 137 days before and 497 +/- 167 days after AVR. CFR measurements were carried out according to a standard protocol, with a vasodilator stimulus dipyridamole (0.56 mg/kg for 4 min) and peak diastolic velocity measurements at 6 min.
Results: Initially, the average peak gradient of aortic stenosis was 89.5 +/- 22.4 mm Hg. After AVR, it decreased to 26.2 +/- 9 mm Hg. Left ventricular mass was significantly lower after AVR: 354.9 +/- 107.9 g versus 223.8 +/- 73.6 g (p < 0.001). The average baseline diastolic velocity measured by pulsed Doppler in the left anterior descending coronary artery amounted to 62.2 +/- 25.5 cm/s before and 40.1 +/- 13.6 cm/s after AVR. The difference was statistically significant (p < 0.01). The average diastolic velocity at maximum stress equaled 117 +/- 42.8 cm/s pre- and 91.5 +/- 34 cm/s postoperatively (p < 0.005). The calculated CFR before AVR amounted to 1.96 +/- 0.5 and increased to 2.37 +/- 0.8 postoperatively. The difference was statistically significant (p < 0.05).
Conclusion: Prosthetic AVR is of considerable benefit concerning the CFR in patients with a normal coronary angiogram after a long-term follow-up.