Non obstructive coronary plaques need not percutaneous coronary interventions, but some of them may lead on to acute coronary events later on. The calcified plaques may not lead on to events, but the vulnerable plaques with a lipid rich core and a thin fibrous cap are the ones prone for fissuring of the cap or rupture which leads an intra coronary thrombus formation and a consequent acute coronary event.
Kristensen TS and associates [Kristensen TS et al. Prognostic Implications of Nonobstructive Coronary Plaques in Patients With Non–ST-Segment Elevation Myocardial Infarction. A Multidetector Computed Tomography Study. J Am Coll Cardiol, 2011; 58:502-509] evaluated non obstructive coronary plaques in those with non ST elevation myocardial infarction and followed them up. Over three hundred patients were underwent 64 slice multidetector computed tomography (MDCT) coronary angiography and coronary artery calcium scoring before conventional coronary angiography. Plaque composition and volume were measured quantitatively for all non obstructive coronary lesions. Standard guideline based invasive treatment was given. Twenty three patients had a cardiac event at a median follow up of sixteen months. Increasing amount of non calcified plaque was associated with age, male sex and diabetes mellitus. Total volume of non calcified plaque was independently associated with an increased hazard ratio. But Agatston score or the amount of calcium in the non obstructive lesions were not associated with increased risk.