The effect of balloon angioplasty on vasa vasorum blood flow in canine coronary arteries.

To assess the effects of balloon dilatation on vasa vasorum flow, we performed percutaneous transluminal coronary angioplasty on the circumflex arteries of 12 dogs. Left anterior descending and circumflex coronary vasa vasorum flows were measured with radioactive microspheres at baseline, during, and 10 minutes after a 3-minute, 8 atm balloon inflation. With inflation, vasa vasorum flow at the balloon dilatation site profoundly decreased (from 0.25 +/- 0.08 to 0.03 +/- 0.01 ml/min/gm). The flow returned to normal within 10 minutes after deflation. This effect was not mediated by hemodynamic deterioration during coronary occlusion and did not occur in the contralateral coronary artery. Endomyocardial flow in the distribution of the dilated artery decreased markedly during balloon inflation (from 1.14 +/- 1.9 to 0.08 +/- 0.04 ml/min/gm), which confirmed coronary occlusion. We conclude that a prolonged decrease in vasa vasorum flow is not produced by experimental balloon angioplasty, which makes it unlikely that a sustained vasa vasorum flow reduction plays a role in the maintenance of patency or the induction of restenosis.