Provoked Coronary Spasm and Acute Coronary Syndromes

Posted By Joel Hernandez
Journal of the American College of Cardiology Vol. 52, No. 7, 2008
Background
Chest pain at rest is a frequent symptom in the emergency room. Acute coronary syndrome (ACS) is suspected in patients with elevation of cardiac markers, ischemic electrocardiographic changes, or simply typical clinical symptoms of unstable (usually resting) angina. However, of all patients with suspected ACS who undergo coronary angiography, up to 30% have nonobstructed coronary arteries. We sought to clarify how many of these patients suffer from coronary spasm as a possible cause of their chest pain.
Methods
In a prospective study from June to December 2006, all patients with suspected acute coronary syndrome (ACS) who underwent coronary angiography and had no culprit lesion underwent intracoronary provocation with acetylcholine (ACH). The ACH testing was considered positive at a vasoconstriction of ≥75% relative to the diameter after intracoronary nitroglycerine when the initially reported symptoms could be reproduced.
Results
Of 488 consecutive patients, 138 had no culprit lesion (28%). Twenty-two were found to have another diagnosis. The ACH testing was performed in 86 of the remaining 116 patients. In 42 patients, coronary spasm was verified (49%).
Conclusions
Every fourth patient with ACS had no culprit lesion. Coronary spasm could be documented in nearly 50% of the patients tested by ACH. Coronary spasm is a frequent cause of ACS and should regularly be considered as a differential diagnosis.

Comment: Very interesting, since this contributes to the idea that many patients (up to 30%) can have acute coronary syndromes without having fixed coronary lesions. Of this 30%, 50% could be attributed to vasospasm. In previous studies, intravenous ergonovine was used instead of intracoronary acetylcholine, being the proportion of patients positive for vasospasm inferior, thus it seems that the test with intracoronary acetylcholine is more sensitive.