Coronary spasm: It's common, but it's still unsolved

Abstract

Coronary spasm is caused by a transient coronary narrowing due to the constriction of epicardial coronary artery, which leads to myocardial ischemia. More than 50 years have passed since the first recognition of coronary spasm, and many findings on coronary spasm have been reported. Coronary spasm has been considered as having pivotal roles in the cause of not only rest angina but also exertional angina, acute coronary syndrome, and heart failure. In addition, several new findings of the mechanism of coronary spasm have emerged recently. The diagnosis based mainly on coronary angiography and spasm provocation test and the mainstream treatment with a focus on a calcium-channel blocker have been established. At a glance, coronary spasm or vasospastic angina (VSA) has become a common disease. On the contrary, there are several uncertain or unsolved problems regarding coronary spasm, including the presence of medically refractory coronary spasm (intractable VSA), or an appropriate use of implantable cardioverter defibrillator in patients with cardiac arrest who have been confirmed as having coronary spasm. This editorial focused on coronary spasm, including recent topics and unsolved problems.

Keywords: Coronary vasospasm; Medically refractory coronary spasm; Variant angina; Vasospastic angina.

Figure 1

A representative case with coronary spasm and coronary stenosis. The patient, who had chest symptoms for 20 min at rest, accompanied with cold sweating, was admitted to our institution for the evaluation of his chest symptoms. A: Coronary angiography showed coronary stenosis at the distal segment of the left circumflex coronary artery, which cannot be considered as the cause of his chest symptoms; B: The spasm provocation test using 100 µg of acetylcholine showed diffuse coronary spasm throughout the left anterior descending coronary artery, accompanied with usual chest pain, which had been restored after nitroglycerin injection. Coronary stenosis and spastic segments were indicated by bold arrow and plain arrows, respectively.

Figure 2

A case of coronary spasm, which was documented by sequential spasm provocation test, which was performed after the routine coronary angiography, vasodilator administration, and preprocedural infusion of nitroglycerin. A: The patient had chest symptoms at exercise early in the morning. Coronary computed tomography angiography showed stenosis of the left anterior descending coronary artery. However, the coronary angiography showed no significant coronary stenosis; B: Because the presence of vasospastic angina was suspicious, the spasm provocation test was performed despite the intracoronary infusion of nitroglycerin and calcium channel blocker intake. The standard doses of acetylcholine (ACh, up to maximal 200 μg) did not cause coronary spasm; C: Consequently, we performed the sequential spasm provocation test: 120 μg of ergonovine maleate was infused first followed by 200 μg of ACh, showing the presence of coronary spasm (right panel) and obtained the diagnosis of vasospastic angina. The spastic site was indicated by an arrow. Ach: Acetylcholine; EM: Ergonovine maleate.