Quantitative demonstration of dipyridamole-induced coronary steal and alteration by angioplasty in man: analysis by simultaneous, continuous dual Doppler spectral flow velocity.

In the course of studying the effects of coronary angioplasty on branch vessel flow using two Doppler flow velocity guidewires, we quantitated simultaneous blood flow responses proximal and distal to a stenosis. The alterations of flow documented a horizontal epicardial steal induced during dipyridamole hyperemia, hyperemic flow reversal by intravenous aminophylline, and subsequent normalization of distal hyperemia after endoluminal enlargement by successful angioplasty. The quantitative physiology of the patient described here confirms one postulated mechanism of abnormal myocardial perfusion stress scintigraphy. Continuous dual flowire spectral coronary flow determinations appear to be a valuable method in verifying postulated mechanisms of various pharmacologic and mechanical stimuli influencing coronary blood flow in patients with atherosclerotic coronary artery disease.