Rapid Progression of Coronary Atherosclerosis by Coronary Artery Spasm Leading to Acute Coronary Syndrome
A 67-year-old normotensive, normolipidemic man presented with short-lasting chest pain followed by syncope. Intracoronary ergonovine maleate (40 μg) provoked a severe spasm in the middle portion of right coronary artery (Figure 1A and 1B, arrow), but there was no significant (>50%) right or left coronary artery disease after intracoronary nitrates (Figure 1C). The patient was diagnosed as having vasospastic angina.
Three years later, he presented with sustained, nitroglycerin-resistant chest pain at our emergency room. Emergent coronary arteriography revealed a high-grade stenosis where coronary spasm had been documented earlier (Figure 2A, arrow). Intracoronary administration of isosorbide dinitrate improved distal filling but failed to dilate the stenosed segment (Figure 2B). Intravascular ultrasound confirmed coronary plaque at that segment (Figure 2B, inset), and a bare metal stent was successfully implanted (Figure 2C). Serial changes in serum enzymes confirmed the diagnosis of acute non–ST-elevation myocardial infarction.
Although coronary spasm has been implicated to cause atherosclerosis progression over years,1 there are few reports demonstrating a critical role of coronary artery spasm in rapid plaque progression and the development of acute coronary syndrome. Because there was no disease progression in left coronary artery segments, it was assumed that focal spasm might have contributed to a ruptured atheromatous plaque in our patient, leading eventually to myocardial infarction. Previous experimental studies have shown that coronary artery spasm could cause intraplaque hemorrhage and acute myocardial infarction in the swine model.2 Thus, coronary vasospasm may play an important role in the pathogenesis of not only variant angina but also acute coronary syndrome, as seen in this patient.
Kuga T, Tagawa H, Tomoike H, Mitsuoka W, Egashira S, Ohara Y, Takeshita A, Nakamura M. Role of coronary artery spasm in progression of organic coronary stenosis and acute myocardial infarction in a swine model: importance of mode of onset and duration of coronary artery spasm. Circulation. 1993; 87: 573–582.