The natural history of unheralded complex coronary plaques

Objectives. This study sought to assess the behavior of unheralded complex lesions in patients with no previous history of acute coronary ischemia. Background. Angiographically complex coronary stenoses appear to originate from plaque disruption and are associated with rapid progression early and late after acute coronary events. Complex lesions may occur without symptoms, but neither the incidence nor the behavior of these unheralded complex lesions is known. Methods. We studied 222 patients with chronic stable angin who were on waiting list for single-vessel percutaneous transluminal coronary angioplasty of an unoccluded lesion and underwent repeat angiography immediately before the procedure as part of routine practice or shortly after coronary event. Patients with previous episode of myocardial infarction or unstable angin were not included. Angiograms were analyzed quantitatively and qualitatively using established methods. change of ±15% stenosis severity or total coronary occlusion defined categoric change. Results. At first angiography, there were 52 unheralded complex target lesions (23%) and 170 smooth target stenoses (77%). Stenosis severity did not differ between complex and smooth target lesions at first and second angiography at mean (±SD) interval of 7 ± 4 months. At follow-up, seven complex lesions had progressed (14%) compared with six smooth lesions (4%, p < 0.02). Total occlusion developed in four complex lesions and one smooth lesion. Overall, complex stenoses progressed by 3 ± 13% compared with 0.5 ± 7% in the smooth stenoses (p = 0.15). Complex stenoses were 4.2 times more likely to progress than smooth stenoses (95% confidence interval 1.2 to 15.2 [Cornfields method]). Clinical events developed in seven patients. One complex lesion regressed and became smooth, and three smooth stenoses became complex at follow-up. Conclusions. Morphologically complex stenosis can develop without an episode of acute coronary ischemi and are relatively common in patients awaiting single-vessel angioplasty. Our study demonstrates that like their clinically heralded counterparts, these unheralded complex stenoses are at higher risk of progression than smooth stenoses.