Aims: To determine the incidence of intraventricular thrombi in patients who died of acute myocardial infarction, as well as to define the clinico-anatomical parameters of the population with thrombi. CONCEPT OF THE STUDY: To apply a clinical as well as an anatomical protocol of prospective study, in patients who died of acute myocardial infarction. The clinical protocol contemplates 64 parameters and the anatomical protocol contemplates 34. in the anatomical study were used very discriminative technics, already presented in previous papers. PLACE OF THE STUDY: The study took place in a CCU and pathological department of an University Hospital.
Material and methods: 193 patients who died successively of acute myocardial infarction in a CCU between 1983 and 1986. The only criteria for the inclusion in the study was the possibility of doing a necropsy study, which was done in 77% of the patients who died in that period. The study was a prospective one, being excluded only the patients in whom the anatomical study didnt confirm recent myocardial infarction. The clinical data were observed during the stay in the CCU using a protocol developed for this study. In the anatomical study a protocol developed by the authors was applied, using very discriminative anatomical quantification technics of the infarct size as well as of the coronary obstruction degree by atherosclerotic plaques. All data were stored and treated in a computer program developed for this study.
Results: From the 193 cases that have been studied, 88 (43%) presented thrombus in at least one of the ventricular cavities, 38 (26%) only in left ventricle, 15 (8%) only in right ventricle and 35 (18%) in both ventricles. The set with thrombus has presented a few characteristics which granted it some individuality. Thus, this group presented: a higher delay between the beginning of acute myocardial infarction and the admission in the CCU (and so in the beginning of the anticoagulant therapy), lower prevalence of diabetes, higher prevalence of left ventricular failure (Killip class III or IV), higher prevalence of cardiogenic shock and so a higher need of inotropic therapy, higher heart weight, higher prevalence of auricular thrombi and bigger infarct size when evaluated by a QRS score. In the group with left ventricular thrombi, the anterior infarct was more frequent and in the group with right ventricular thrombi the right ventricular infarct was also more frequent. The systemic embolism was uncommon in this group (1 case in 193 patients).
Conclusions: 1. The intraventricular thrombi occurs in about half of the patients who died of acute myocardial infarction. 2. The group with thrombi has presented some characteristics which makes it different from the group with no thrombi. 3. The delay in the beginning of the anticoagulant therapy seems to be a risk factor of intraventricular thrombosis.