Blood velocity measurements during selective coronary angiography before and after percutaneous transluminal coronary angioplasty

The velocity of blood flowing down a coronary artery may provide an index of myocardial perfusion, independent of the need for measuring the amount of myocardium supplied by a vessel. The velocity of the leading edge of contrast material was therefore measured before and after percutaneous transluminal coronary angioplasty in 15 patients utilizing digitized images from routine coronary angiography. The velocity (mean +/- SD) before percutaneous transluminal coronary angioplasty in the 15 patients was 11.9 +/- 6.0 cm/s, increasing to 21.7 +/- 8.7 cm/s after (P less than 0.01). There was a correlation between the percent change in velocity and the change in percent stenosis before and after percutaneous transluminal coronary angioplasty (r = 0.65; P less than 0.001). The mean absolute interobserver and intraobserver variabilities for the velocity measurements were 2.1 and 1.8 cm/s, respectively. Measurement of coronary flow velocity from data obtained at the time of routine coronary angiography is an easily performed reproducible technique, which may be used to assess the results of an intervention such as percutaneous transluminal coronary angioplasty.