Comparison of coronary flow reserve between focal and diffuse vasoconstriction induced by ergonovine in patients with vasospastic angina.

Decreased coronary flow reserve has been reported in patients with ergonovine-induced coronary vasoconstriction by the thermodilution method. To assess the difference of coronary flow reserve between patients with focal and diffuse vasospasm, after the vasospasm is discontinued by injection 3 mg of isosorbide dinitrate, phasic flow velocities of the diseased coronary artery were recorded at rest and during hyperemia (140 microg/kg/min of adenosine infusion intravenously) using a 0.014-inch, 15-MHz Doppler guidewire in 26 patients with ergonovine-induced coronary vasospasm (0.2-mg ergonovine injection intravenously), including 12 patients with focal (>90% stenosis), 14 patients with diffuse vasospasm (>50%), and 11 controls with normal coronary arteries without vasospasm. Although time-averaged peak velocity in cases with diffuse and focal vasospasm was not significantly different compared with that in controls at baseline (22 +/- 7, 18 +/- 5 vs 20 +/- 7 cm/s, respectively, NS), it was significantly lower in patients with diffuse vasospasm than in cases with focal vasospasm and in controls during hyperemia (43 +/- 13 vs 64 +/- 18, 61 +/- 19 cm/s, respectively, p <0.01). As a result, coronary flow reserve obtained from the ratio of hyperemic/baseline time-averaged peak velocity was significantly lower in patients with diffuse vasospasm than that in controls (1.9 +/- 0.4 vs 3.1 +/- 0.4, p <0.01), although it was not significantly different between the subjects with focal vasospasm and controls (3.5 +/- 0.7 vs 3.1 +/- 0.4, NS). Thus, coronary flow reserve is maintained normally in patients with focal vasospasm and limited in those with diffuse vasospasm. Microvascular impairment could exist further in cases with diffuse vasospasm, although similar endothelial dysfunction of the epicardial coronary artery is observed in focal and diffuse vasospasm.