Massive PE cause 50,000 deaths per year. Incidence probably rising with increasing surgical interventions, advances in intensive care, and longevity. A dark red clot forming a cast, equivalent to clotted blood in a test tube, due to stasis. Postmortem clots are ruled out by gross features, lacking cast form, wall and valve impressions. Occur in cardiac chambers, aorta, and iliacs.
Postmortem clots are cord like and elastic.
Fibrin component not visible. Outer rims may show a few lines of Zahn. This is proof of antemortem genesis because blood flow needed. But, meticulous study of total thrombus will reveal focus of endothelial injury with nidus of platelet and fibrin thrombus. Vegetations of endocarditis can also embolize to coronary arteries with myocardial infarction.