Angina and Myocardial Infarction Without Significant Coronary Stenosis

• Myocardial Infarction and Unstable Angina with Absence of Significant Angiographic Stenosis
• Overview
• Severe Reversible Acute Cardiomyopathy Secondary to Severe Stress
• Coronary Spasm and Myocardial Infarction or Unstable Angina

Coronary spasm and myocardial infarction or unstable angina

The CASPER study published in 2008 (J Am Coll Cardiol 2008;52:523–7) found that of consecutive patients with myocardial infarction or unstable angina

• spproximately one in four did not have a culprit lesion at angiography
• only a small proportion of those with STEMI or NSTEMI did not have a culprit lesion at angiography
• more than half of patients with a diagnosis of unstable angina did not have a culprit lesion at angiography

Provocative testing for spasm was performed using acetyl-choline in most of those without a culprit lesion, finding

• 49% had some inducible spasm
• of those that had inducible spasm
  • 58% had severe (>75% stenosis) spasm
  • Most of those with severe spasm had symptoms at the time of infusion of acety-choline. Some of those with less severe spasm also had symptoms.

The prevalance of inducible spasm in this study was higher than another study of caucasian subjects but not as high as some studies from Japan.

In this same issue (J Am Coll Cardiol 2008;52) Japanese investigators reported on the prevalence of inducible spasm in those that had had myocardial infarction treated with coronary artery stenting. Spasm was seen in 70% of infarct related arteries and 50% of non-infarct related arteries. Those with inducible spasm were more likely to have an adverse cardiac event during follow-up. It is thought that spasm occurs at the sites of minor plaque with associated endothelial dysfunction.

Hitesh Patel, Cardiologist
May, 2009