Can Coronary Vasospasm Cause Myocardial Infarction?
Yes, coronary vasospasm can definitively cause myocardial infarction—prolonged vasospasm results in MI, high-degree AV block, life-threatening ventricular arrhythmias, or sudden death. 1
Classification and Mechanism
Coronary vasospasm is formally recognized as a cause of MI in the Universal Definition of Myocardial Infarction classification system. Vasospasm-induced MI is classified as Type 2 MI, where coronary vasospasm and/or endothelial dysfunction create an imbalance between myocardial oxygen supply and demand, leading to myocardial necrosis. 1
The mechanism involves:
- Focal coronary spasm causing complete or near-complete coronary occlusion of an epicardial artery, resulting in transmural ischemia 1
- Dysfunctional endothelium exposing smooth muscle to vasoconstrictors (catecholamines, thromboxane A2, serotonin, histamine, endothelin) 1
- Imbalance between vasodilator factors (prostacyclin, nitric oxide) and vasoconstrictor factors (endothelin, angiotensin II) favoring vasoconstriction 1
Clinical Presentation and Risk
Most vasospastic angina attacks resolve spontaneously without MI, but prolonged spasm is the critical determinant for progression to infarction. 1
Key clinical features indicating higher MI risk:
- Syncope during chest pain episodes suggests severe ischemia from acute occlusion due to focal spasm 1
- Attacks occurring in clusters with early morning predominance (circadian variation) 1
- Multivessel disease present in 19% of vasospastic angina patients, increasing MI and death risk 1
In the active "waxing phase" of vasospastic disease, patients face elevated risk of MI and sudden cardiac death, with cardiovascular death rate of 0.5% per year and MI risk of 1.2% per year. 1
Diagnostic Considerations
The diagnosis requires documentation of transient ST-segment elevation during chest pain that resolves when symptoms abate, typically responding exquisitely to nitroglycerin 1. However, this represents the classic presentation—persistent vasospasm leading to MI may not show the periodic, reversible pattern of variant angina. 1
Critical diagnostic points:
- Even angiographically normal coronary segments often harbor mural atherosclerosis on intravascular ultrasound, predisposing to localized endothelial dysfunction and spasm 1
- Provocative testing with ergonovine is positive in up to 20% of patients with recent MI, suggesting vasospasm as a contributing mechanism 1
- Spasm can occur simultaneously at multiple sites and may be superimposed on either obstructive or non-obstructive coronary disease 1
Clinical Pitfalls
Do not dismiss vasospasm as a benign condition—it causes serious complications including MI, particularly when spasm is prolonged or involves multiple vessels 2, 3, 4. Transient spasm causes chest pain; persistent spasm causes acute MI. 4
The greater the number of diseased arteries with vasospastic tendency, the higher the risk of death or acute MI during follow-up. 1 This underscores that vasospasm in the setting of underlying coronary disease carries particularly elevated MI risk.