Restoration of coronary blood flow in severely narrowed and chronically occluded coronary arteries before and after angioplasty: implications regarding restenosis.

The restenosis rate after recanalization of chronic totally occluded coronary arteries is high. This may be due to a competitive flow or a low coronary flow velocity. This study was designed to assess differences in coronary blood flow velocity between severely narrowed and occluded arteries before and after successful percutaneous transluminal coronary angioplasty. Thirty-five patients were studied including 12 with an occluded vessel (group 1) and 23 with a stenosis (group 2). Rest and peak hyperemic (papaverine) coronary blood flow velocities were measured. Before successful percutaneous transluminal coronary angioplasty, velocity was lower in occlusions than in stenoses (3.8 +/- 2.1 vs 7.9 +/- 4.8 cm/sec; p < 0.02), whereas resistance was higher (31.7 +/- 20.8 vs 13.7 +/- 7.0 mm hg/cm/sec, respectively; p = 0.0009). There was no significant difference in vasodilator reserve between the two groups. After successful percutaneous transluminal coronary angioplasty, the velocity increased in both groups and the resistance index decreased. Velocity and resistance were similar in the two groups. The vasodilator reserve did not change after the procedure. It was concluded that the coronary flow velocity achieved after successful recanalization of chronic totally occluded arteries is similar to that observed after dilation of stenoses. These results do not support the hypothesis that the high rate of restenosis in recanalized chronically occluded vessels is due to differences in post-percutaneous transluminal coronary angioplasty blood flow velocity.