Background: Clarification of frequency and distribution of yellow plaques and disrupted plaques will increase understanding of acute coronary syndrome (ACS) onset.
Methods and results: Consecutive patients with ACS (n=75) or without ACS (n=90) who received coronary angioscopic examination were studied. Distance from ostium to yellow plaques, diameter stenosis and vessel wall irregularity at the site of yellow plaques, their yellow color grade (grade 13) and if they had thrombus were analyzed. Yellow plaques with thrombus were regarded as disrupted. Average number of yellow plaques, grade-3 yellow plaques and disrupted yellow plaques per vessel was 4.0, 0.87 and 1.0, respectively. The number of grade-3 yellow plaques and disrupted yellow plaques per vessel were larger in ACS than in non-ACS patients. Yellow plaques were distributed diffusely in the right coronary artery but more in mid-segments in the left anterior descending coronary artery and left circumflex coronary artery. Diameter stenosis in the non-culprit segments was severer at disrupted than at non-disrupted yellow plaques. Vessel wall irregularity was detected more frequently at disrupted than at non-disrupted yellow plaques.
Conclusions: Approximately 4 yellow plaques, 1 grade-3 yellow plaque and 1 disrupted yellow plaque were detected per vessel. About 25% of detected yellow plaques were disrupted. More grade-3 yellow plaques and disrupted yellow plaques were detected in ACS than in non-ACS patients. These findings strengthen the association between yellow plaques detected by angioscopy and ACS events.