Effect of shear stress on plaque rupture

Abstract

Apreviously asymptomatic 40-year-old woman was admitted to the emergency department with acute onset of left-sided chest pain on exertion. The initial electrocardiogram showed ST-segment elevation in the anterior leads, suggesting an anterior ST-segment elevation myocardial infarction. Symptoms improved after treatment with oxygen, acetylsalicylic acid and oral nitroglycerin, although the ST-segment elevation persisted. Emergency cardiac catheterization demonstrated an ulcerated culprit lesion just at the entrance of an intramyocardial coronary segment (Figure 1). No other coronary lesions were documented. The disruption of the normal left coronary artery anatomy created by the presence of the intramyocardial segment may have induced changes in vessel wall shear stress at this point, and may have prompted plaque rupture. An intra-coronary 3 mm × 24 mm paclitaxel-eluting stent was successfully implanted; this modified the left anterior descending artery architecture by correcting the angle of the intramyocardial segment entrance (Figure 2). No incidents occurred during admission, and the patient was discharged on day 4, with treatment with acetylsalicylic acid, clopidogrel, enalapril, atenolol and atorvastatin. Figure 1 Coronary angiogram showing an ulcerated plaque (arrow) at the entrance of an intramyocardial segment in the left anterior descending artery. Inset: Area in detail Figure 2 Coronary angiogram after stent implantation at the entrance of the intramyocardial segment (arrow). The angle of the intramyocardial segment entrance has been successfully corrected