The pathological basis and microanatomy of occlusive thrombus formation in human coronary arteries

Abstract

Myocardial necrosis, usually called infarction, occurs in different patterns. A common form is necrosis of one segment of the left ventricle, i.e., anterior, septal, lateral or posterior. This regional infarction is consistently associated with an acute occlusive thrombosis of the artery supplying that region. Diffuse necrosis involving the whole circumference, usually the subendocardial zone, of the ventricle is not consistently associated with thrombi. Occlusive thrombi identified in post-mortem coronary arteriograms have been reconstructed in their entirety from serial sections at 150 μm intervals. Most occlusive thrombi were found to be associated with a dissection track into the intima at an atheromatous plaque. The break into the plaque usually extended over several millimetres, often in spirals, so that a mass of thrombus within the plaque compressed the original lumen. Previous accounts of plaque rupture or cracking greatly underestimated the magnitude of the dissection of blood into the intima.