Cumulative incidence of coronary lesions with vulnerable characteristics in patients with stable angina pectoris: an intravascular ultrasound and angiographic study.

Background: Development of vulnerable lesion may take place simultaneously at many sites of coronary vasculature, therefore causing multisite instability. The prevalence of the phenomenon in stable angina (SA) patients remains unknown. The aim of our study was to assess, in patients with stable angina, the prevalence of coronary plaques with vulnerable characteristics and to ascertain whether the number of such lesions may accumulate.

Methods: Vulnerable plaques are characterised by positive remodelling on intravascular ultrasound (IVUS) and with complex appearance on angiography. We performed preprocedural IVUS in target lesion of 67 patients with SA (46 males, age 55.9). Remodelling index (RI) defined as vessel area at the target lesion divided by that of average reference segments > or = 1.05 was assumed as positive remodelling. Plaques of > or = 30% stenosis on angiography were classified into complex or smooth groups.

Results: Positive remodelling was found in 30 (44.8%) and complex plaque in 16 (23.9%) of 67 target lesions. Multiple complex plaques were present in 21 (31.3%) patients. Plaques with positive remodelling more often were complex on angiography (12/30 vs. 4/37, respectively; p=0.005) and were more often associated by complex plaques at other sites (35/30 vs. 23/37; p=0.04) than the remaining lesions. Moreover, the presence of positive remodelling predicted multiple complex lesions at other sites (OR 5.6; 95% CI 1.7-18.3).

Conclusion: Multiple coronary plaques with vulnerable characteristics are present in nearly one third of patients with stable angina. Incidence of vulnerable lesions may have cumulative character, i.e. the presence of one vulnerable lesion predicts occurrence of further vulnerable plaques.