Transient Collateral Circulation during Coronary Vasospasm
Article Outline
To the Editor:
A 62-year-old man who was a heavy smoker presented to the hospital with chest pain that occurred while he was sleeping. Coronary angiography was performed, which showed collateral vessels from the left anterior descending artery to the right coronary artery but no significant organic stenosis in the left coronary artery. Right coronary angiography was immediately performed, showing severe stenosis of the proximal right coronary artery (Figure 1), although no electrocardiographic changes were observed. Vasospasm of the right coronary artery was treated immediately by intracoronary administration of isosorbide dinitrate. A left coronary angiography performed immediately after the isosorbide dinitrate administration showed disappearance of the collateral vessels from the left anterior descending artery to the right coronary artery seen in the earlier test (Figure 2).
Figure 1.
Initial left coronary angiogram (left: left anterior oblique view) shows the collateral vessels from the left anterior descending artery to the right coronary artery (arrows). Right coronary angiogram (right: left anterior oblique view) shows severe stenosis of the proximal right coronary artery (arrow).
Figure 2.
The vasospasm of the right coronary artery was relieved by administration of isosorbide dinitrate to the right coronary artery, and moderate organic stenosis remained (arrow). The collateral vessels to the right coronary artery, which were seen on the initial left coronary angiogram, can no longer be visualized.
Discussion
A transient appearance of the collateral vessels was observed, which could serve to salvage otherwise jeopardized ischemic areas during coronary vasospasm. In this patient with coronary spastic angina, coronary vasospasm of a major coronary artery might have been associated with transient collateral augmentation supplied by the nonspastic artery during the anginal period.
The development of coronary collateral vessels has been described in a patient with coronary spastic angina associated with ST-segment depression. The collateral vessels disappeared after the vasospasm was relieved by intracoronary administration of isosorbide dinitrate, suggesting that the collateral vessels were formed during coronary vasospasm and localized to the perfused ischemic area, preventing transmural myocardial ischemia.1, 2, 3 These findings indicate that ST-segment depression during coronary vasospasm could be attributed to subendocardial ischemia caused by incomplete occlusion of a large coronary artery and transient reduction or augmentation of collateral blood flow.4
It has been speculated that recruitable collateral vessels can remain patent long after spontaneous attacks of angina have resolved and become visible in the event of a pressure difference between 2 small coronary arteries. This suggests that collateral blood supply may occur transiently through preexisting vessels to perfuse the ischemic area during coronary vasospasm and that such collateral flow might play a role in preventing transmural myocardial ischemia, reducing the severity of ischemia.5
In this case, the collateral vessels from the left anterior descending artery to the myocardial region perfused by the right coronary artery are speculated to have been formed gradually, by repeated myocardial ischemia caused by coronary vasospasm, even in the absence of severe organic stenosis of the right coronary artery. Such a situation is likely to exist in many patients with rest angina associated with ST-segment depression, in which coronary vasospasm has been implicated. The possible reasons why no ischemic ST changes were seen on the electrocardiogram in this case are as follows: the right coronary artery ischemia was released immediately, and the ischemic period was too short for the electrocardiographic changes to appear; the amount of blood supplied by the collateral vessels was sufficient, and significant myocardial ischemia potentially induced by right coronary vasospasm might have failed to occur.
References
- Appearance of collateral circulation in the absence of total occlusive spastic coronary artery: a case report. Angiology. 2005;56:331–334
- . Persistence of recruitable coronary collaterals in the absence of coronary vasospasm in a patient with variant angina. Cardiovasc Intervent Radiol. 1998;21:249–251
- Transient collateral augmentation during coronary arterial spasm associated with ST-segment depression. Circulation. 1983;67:693–698
- Functional significance of transient collaterals during coronary artery spasm. Am J Cardiol. 1985;56:407–412
- Arteriographic features of angina pectoris associated with ST segment depression during coronary arterial spasm. Jpn Circ J. 1983;47:1406–1414
Funding: None.
Conflict of Interest: The authors state that they have no conflict of interest regarding the content of the article.
Authorship: All authors meet the criteria for authorship, including acceptance of responsibility for the scientific content of the article. All authors had access to the data and a role in writing the article.
PII: S0002-9343(09)00955-3
doi:10.1016/j.amjmed.2009.08.021
© 2010 Elsevier Inc. All rights reserved.
