Angiographic measurement of coronary blood flow by video dilution technique

A simplified video dilution technique has been developed whereby neither coronary dimensions nor contrast velocity need be measured to obtain coronary blood flow relative to a control flow. In 6 dogs, the distal left anterior descending coronary artery flow was measured by simultaneous electromagnetic flowmeter and video dilution technique. For the 236 paired measurements, the electromagnetic flow ranged from 23 to 196 ml/min for each series. When the first measure of a series was considered the control, the flow ratio difference between electromagnetic and video dilution values had a standard deviation of 12 per cent. When each series was broken into pairs, flow ratio difference between these values had a standard deviation of 10 per cent. Thus, the video dilution technique allows accurate measurement of coronary blood flow relative to a control state, utilizing only the known amount of contrast medium injected and the image from videotape replay of the injection. A patient is presented to illustrate the technique during coronary angiography. Applications include determination of coronary reserve during reactive hyperemia to assess the hemodynamic significance of coronary lesions, and determination of the effects of drugs upon coronary blood flow.