Edge detection versus videodensitometry for quantitative angiographic assessment of directional coronary atherectomy.

of the angioplasty segment between the concentric and eccentric lesion subgroups was not significant (analysis of variance) at any time after PTCA. The degree of vasoconstriction observed in the angioplasty segment of both the concentric and eccentric lesion subgroups were significantly greater than that of the control segment at 15 and 30 minutes after PTCA (p CO.01 and <0.005, respectively). Figure 4 shows an example of similar spontaneous vasocon-striction after PTCA in 1 patient with a concentric lesion and in a patient with an eccentric lesion. This study demonstrates that the severity and incidence of spontaneous vasoconstriction in the dilated segment after PTCA does not differ in eccentric versus concentric lesions. On the basis of these findings we would propose that the " release " of the media from the diseased intima after PTCA may restore more normal vasomotor reactivity in concentrically diseased coronary segments. This hypothesis may explain why the vasocon-striction in the treated concentric lesions is equal to that observed in eccentric lesions, which have an arc of relatively disease-free wall. Were it not for this " releasing " effect of PTCA one might expect the vasoconstrictor and vasodilator responses in these concentrically diseased segments to be limited by circumferential atherosclerosis.10 The ability of intracoronary nitroglycerin to actively va-sodilate the angioplasty segment provides further evidence of improved segmental arterial compliance in concentric lesions after PTCA. Although lesion eccentricity has been regarded as a " risk factor " for complications after PTCA, this study does not support the notion that these complications are attributable to greater vasospasm in eccentric compared with concentric stenoses. However, given the magnitude of the vasoconstrictor responses observed in some of these patients, it is likely that spontaneous vasoconstriction after PTCA does contribute to acute closure syndromes after PTCA of both eccentric and concentric lesions. Despite prior hypotheses to the contrary, coronary lesion eccentricity does not appear to influence the incidence or severity of spontaneous vasoconstriction in the dilated segment after PTCA. Coronary artery vasoconstriction routinely occurs after percutaneous transluminal coronary angioplasty: a quantitative arteriographic analysis. Evidence for altered epicardial coronary artery autoregulation as a cause of distal coronary vasoconstriction after successful percutaneous transhnninal coronary angioplasty. Coronary vase spasm culminating in thrombosis and infarction following " successful " coronary angioplasty. Relation of restenccis after percutaneous transhnninal coronary angioplasty to vasomotion of the dilated coronary arterial segment. Reactivity of eccentric and concentric stenoses in patients with …