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

Objectives. This study was designed to determine whether coronary vasospasm in patients with variant angina pectoris (VAP) may produce focal organic l esions at the site of vasospasm that would contribute to disease progressio n. Background. Recent clinical angiographic and experimental studies have demo nstrated the potential role of vasospasm in the worsening of organic corona ry stenosis. Methods. We studied histologically the coronary plaques obtained at atherec tomy in 202 patients with moderate to severe coronary stenosis. This popula tion included 22 patients with VAP, 100 patients with chronic stable angina and 80 patients with restenosis following angioplasty or atherectomy. Diag nosis of VAP was based on both the clinical feature of angina at rest assoc iated with ST elevation and a positive response to acetylcholine provocatio n test. Results. The most common histological appearance in 92% of patients with st able angina was hypocellular fibroatheromatous plaques, whereas neointimal hyperplasia was the characteristic feature of the plaque observed in 90% of patients with restenosis. The coronary specimens at the site of spasm in 1 5 of the 22 patients (68%) with VAP demonstrated intimal injuries such as n eointimal hyperplasia (15), thrombus formation (2), and intimal hemorrhage (3). Neointimal hyperplasia was significantly more common in the patients w ith VAP as compared with those with stable angina (68% vs. 8%; p < 0.0001). A rapid progression of organic stenosis within three years was angiographi cally found in 5 of the 22 patients with variant angina. In all five cases, neointimal hyperplasia was the main contributor to the worsening of the or ganic 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 pr imary coronary lesions. Conclusions. Coronary vasospasm may provoke vascular injury that leads to t he formation of neointima in VAP patients similar to that seen with resteno sis, Coronary spasm may thus play a key role in the rapid coronary stenosis progression in certain patients with VAP. (C) 1998 by the American College of Cardiology.