Regional coronary blood flow velocity and vasodilator reserve in patients with angiographically normal coronary arteries

Abstract

To assess the homogeneity of coronary vasodilator reserve between distinct myocardial regions, resting and maximal hyperemic intracoronary blood flow velocities were measured by a 3.0F Doppler 20-MHz catheter in the left anterior descending and circumflex arteries in 21 patients with angiographically normal coronary arteries. Coronary vasodilator reserve was calculated as the ratio of papaverine-induced hyperemic to resting mean coronary flow velocity. Resting coronary flow velocity was similar in both the proximal left anterior descending and circumflex arteries (11 ±9 and 8±5 cm/s, P=NS), but lower than coronary velocity measured more proximally in the left main location (16±8 cm/s, P< 0.05 versus both left anterior descending artery and circumflex artery). Hyperemic velocities measured in the left main location (43 ±14 cm/s) were also higher than those measured in the left anterior descending and circumflex arteries (3O±17 and 22 ±12 cm/s, both P 0.05 versus left main). However, coronary vasodilator reserve calculated for each region was not different (3.04 ± 1.07, 3.25 ±1.29, and 2.85 ±1.11 units for left main, left anterior descending, and circumflex locations, respectively). Coronary vasodilator reserve correlations indicated small differences in individual responses in regional reserve values between left anterior descending and circumflex arteries. These data demonstrate that in angiographically normal coronary arteries, a mild inhomogeneity of regional intracoronary flow velocity responses exists but that coronary vasodilator reserve is not regionally different. Coronary vasodilator reserve measured at a single coronary locus can be used to estimate more distal regional coronary reserve in patients without coronary disease.