Correlations Between Recruitable Coronary Collateral Flow Velocities, Distal Occlusion Pressure, and Electrocardiographic Changes in Patients Undergoing Angioplasty

: Direct assessment of coronary collateral flow has been difficult in humans. The goal of this study was to correlate the magnitudes and waveform characteristics of recruitable coronary collateral flow velocity measured with Doppler guidewire with other hemodynamic and functional indexes of collateral circulation in patients during angioplasty. Twenty-six patients [age 60 +/- 10 (SD) years] were studied for measurements of flow velocity at the distal segment of the dilated vessel. Collateral flow signals were demonstrated in 18 patients (69%) during balloon inflation. There was a weak yet significant positive correlation between the magnitude of collateral flow velocity and distal occlusion pressure (p < 0.01). The sum of ischemic ST elevation on the 12-lead electrocardiogram was inversely correlated with distal occlusion pressure, but not with the magnitude of collateral flow velocity. Subgroup analysis between patients with (n = 18) and without (n = 8) ST elevation during balloon inflation revealed higher collateral flow velocity signals (p < 0.0001) and greater systolic components of collateral flow in the latter group (p < 0.0001). Thus, functionally significant coronary collaterals showed greater velocity signals and systolic predominance in flow pattern. The functional capacity of human coronary collaterals may be semiquantitated using the Doppler guidewire technique.