Elastic recoil contributes to the residual lumen reduction immediately after PTCA. We evaluated the factors to influence on immediate elastic recoil after the successful PTCA.

88 patients(96 lesions) were studied by quantitative angiography. Angiograms were obtained in two identical near orthogonal projection before PTCA and immediately after the last balloon deflation.

Immediately after PTCA, minimal luminal diameter increased from 0.7±0.6mm to 1.9±0.6mm and percent diameter stenosis was reduced from 77±20 to 34±21%. The calculated mean elastic recoil was 0.5±0.7mm in diameter and % elastic recoils were lesser both in calcified(3±23 vs 23±24%, p=0.04) and thrombotic(9±20 vs 23±35%, p=0.02) lesions. The elastic recoil increased significantly according to the inflation diameter of balloon(r=0.32, p<0.01. No significant correlation between the immediate elastic recoil and age, sex, risk factors, eccentricity and lesion length was shown.

The elastic recoil immediately after a successful PTCA was dependent on the existance of calcium and thrombus on the target lesion and on the balloon size at the maximal inflation.