Coronary flow reserve improves after aortic valve replacement for aortic stenosis: An adenosine transthoracic echocardiography study

OBJECTIVES The goal of this study was to assess coronary flow reserve (CFR) before and after aortic valve replacement (AVR). BACKGROUND Coronary flow reserve is impaired under conditions of left ventr icular (LV) hypertrophy. It is not known whether CFR improves with regressi on of LV hypertrophy in humans. METHODS We investigated 35 patients with pure aortic stenosis, LV hypertrop hy and normal coronary arteriograms. Patients underwent adenosine transthor acic echocardiography on two occasions-immediately before AVR and six month s postoperatively. Left ventricular mass, distal left anterior descending c oronary artery (LAD) diameter, flow and CFR were assessed on each occasion. RESULTS Distal LAD diameter was successfully imaged in 30 patients (86%), a nd blood flow was successfully imaged in 27 (77%). Paired data were subsequ ently available in 24 patients, of whom 14 were men, mean age 68.1 +/-: 12. 5 years, body mass index 24.5 +/- 2.0 kg/m(2), aortic valve gradient 93 +/- 32 mm Hg. Pre- to post-AVR a significant decrease nas seen in LV mass (271 +/- 38 vs. 236 +/- 32g, p < 0.01) and LV mass index (154 +/- 21 vs. 134 +/ - 21g/m(2), p < 0.01). Distal LAD diameter fell from 2.27 +/- 0.37 to 2.23 +/- 0.35 mm, p = 0.08). Pre- to post-AVR there was no significant change in resting parameters of peak diastolic velocity (0.43 +/- 0.16 vs. 0.41 +/- 0.11 m/s), distal LAD flow 23.3 +/- 10.1 vs. 20.9 +/- 5.2 ml/min or distal LAD flow scaled for LV mass (8.7 +/- 3.8 vs. 9.0 +/- 2.5 ml/min/100 g LV ma ss), but there was significant increase in hyperemic peak diastolic velocit y(0.71 +/- 0.26 vs. 1.08 +/-. 0.24 m/s; p < 0.01), distal LAD how (37.8 +/- 11.3 vs. 53.5 +/- 16.1 ml/min; p < 0.01) and distal LAD flow scaled for LV mass (14.3 +/- 5.0 vs. 23.3 +/- 8.5 ml/min/100 g LV mass; p < 0.01). Coron ary flow reserve, therefore, increased from 1.76 +/- 0.5 to 2.61 +/- 0.7. CONCLUSIONS Coronary flow reserve increases after AVR for aortic stenosis. This increase occurs in tandem with regression of LV hypertrophy. (C) 2000 by the American College of Cardiology.