Histological evaluation of coronary plaque in patients with variant angina: relationship between vasospasm and neointimal hyperplasi in primary coronary lesions

Objectives. This study was designed to determine whether coronary vasospasm in patients with variant angin pectoris (VAP) may produce focal organic lesions at the site of vasospasm that would contribute to disease progression. Background. Recent clinical angiographic and experimental studies have demonstrated the potential role of vasospasm in the worsening of organic coronary stenosis. Methods. We studied histologically the coronary plaques obtained at atherectomy in 202 patients with moderate to severe coronary stenosis. This population included 22 patients with VAP, 100 patients with chronic stable angin and 80 patients with restenosis following angioplasty or atherectomy. Diagnosis of VAP was based on both the clinical feature of angin at rest associated with ST elevation and positive response to acetylcholine provocation test. Results. The most common histological appearance in 92% of patients with stable angin was hypocellular fibroatheromatous plaques, whereas neointimal hyperplasi was the characteristic feature of the plaque observed in 90% of patients with restenosis. The coronary specimens at the site of spasm in 15 of the 22 patients (68%) with VAP demonstrated intimal injuries such as neointimal hyperplasi (15), thrombus formation (2), and intimal hemorrhage (3). Neointimal hyperplasi was significantly more common in the patients with VAP as compared with those with stable angin (68% vs. 8%; p < 0.0001). rapid progression of organic stenosis within three years was angiographically found in 5 of the 22 patients with variant angina. In all five cases, neointimal hyperplasi was the main contributor to the worsening of the organic lesion at the site of spasm. These histological findings in patients with VAP extremely resembled those in restenosis. Except for vasospasm, no factors significantly predicted the presence of neointimal formations in primary coronary lesions. Conclusions. Coronary vasospasm may provoke vascular injury that leads to the formation of neointim in VAP patients similar to that seen with restenosis. Coronary spasm may thus play key role in the rapid coronary stenosis progression in certain patients with VAP.