EFFECTS OF LUMINAL ECCENTRICITY ON SPONTANEOUS CORONARY VASOCONSTRICTION AFTER SUCCESSFUL PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

Over the past several years there has been increasing recognition that spontaneous coronary artery vasoconstriction, or spasm, can occur in the dilated coronary segment after percutaneous transluminal coronary angioplasty (PTCA). This vasoconstriction after PTCA has been quantitated in clinical studies,1,2 and has been well described in clinical series and in case reports.3-6 Although the etiology of vasoconstriction after PTCA is not fully understood, several mechanisms have been postulated, including the release of vasoactive substances from aggregating platelets at the site of endothelial injury and the release of endothelium-derived constricting factor(s) after balloon trauma.7 Coronary spasm has been demonstrated to be one possible mechanism of acute vessel closure after successful PTCA.5,6 Furthermore, clinical studies have suggested a significant correlation between spontaneous or provoked vasospasm in the dilated coronary segment with increased restenosis rates after PTCA.8. It has been demonstrated that lesion eccentricity may be a risk factor for acute coronary closure after PTCA.9 The observations that eccentric lesions may have a greater potential for dynamic changes in caliber in response to vasoactive stimuli10 has led to speculation that vasospasm may be more pronounced after PTCA in eccentric compared with concentric lesions, leading to a greater incidence of acute closure, and possibly late restenosis.11,12 This study was designed to examine whether there is any relationship between angiographically determined lesion eccentricity and the severity of spontaneous vasoconstriction early after PTCA in the dilated coronary segment. © 1991.