[Intraventricular thrombi in acute myocardial infarct. The Iberian Multicenter Study. Presentation of the study protocol and various preliminary results].

OBJECTIVE

To evaluate the incidence of left intraventricular thrombosis and systemic embolism after acute myocardial infarction, as well as to determine the risk factors of each one of them. To study the morphologic aspects of the thrombus and its relation with systemic embolism. CONCEPTION AND POPULATION: 1505 consecutive patients with acute myocardial infarction from six Iberian Hospital Coronary Care Units--five from Spain and one from Portugal--were studied. All protocols included a clinical evaluation and a M-mode and 2D echocardiographic study at days 1, 3, 7 at hospital discharge, as well as at months 1, 3, 6, 12, and 24 of the follow-up. In the intraventricular thrombus evaluation just the III and IV Asinger grades were considered.

RESULTS

From the total studied patients an echocardiographic study of good quality for thrombus evaluation was found in 1360, and 305 (22.3%) of these had a left ventricular thrombus. In anterior infarctions the incidence of thrombus was 39.9%, and in the other localizations was 11.2%. In what concerns the thrombus morphologic aspects, we found a small thrombus (less than 4 cm2) in 71% of the cases, and a big one (greater than or equal to 4 cm2) in 29%; the shape was laminar in 53.6%, protuberant in 41.7% and pediculated in 4.6%; the outline was smooth in 56.7% and irregular in 43.3%; the echodensity was considered homogeneous in 60.1% heterogeneous in 37.6% and cavitated in 3.3%. Of the several parameters evaluated the following were correlated with left intraventricular thrombosis: anterior localization of the infarction, left ventricular failure, ventricular aneurysm, post infarction angina, bundle branche block and no thrombolytic therapy. The incidence of systemic embolism in a mean follow-up of 290 days was 3.96%, being maximum in the first month (3.4%), but an embolic episode still occurred in the following months in 3.02% of the cases. Systemic embolism correlated with left ventricular thrombus, the pediculated shape and the big size of it, as well as with the oldest patients.

CONCLUSIONS

A high incidence of left intraventricular thrombosis after acute myocardial infarction correspond to a low incidence of systemic embolism. Some parameters correlated with intraventricular thrombus or with embolism, what allowed us to consider them as risk factors of these clinical entities.