Rapid reperfusion has been shown to decrease mortality and improve left ventricular (LV) function. Previous studies have reported that LV thrombus (LVT) is a major complication of ST-segment elevation acute anterior wall myocardial infarction (AMI). There are little data on LVT in the current primary percutaneous coronary intervention (PPCI) era. We sought to demonstrate the incidence of LVT after AMI in patients treated with PPCI compared with those treated with thrombolysis or with conservative management.

In a 6-year period, 642 patients with anterior wall AMI and echocardiography were treated with PPCI (n = 297), thrombolysis (n = 128), or conservative treatment (n = 217). Left ventricular thrombus was defined as an echodense mass adjacent to an abnormally contracting myocardial segment.

The rate of LVT among anterior wall AMI was 6.2%. Predictors for LVT were reduced ejection fraction (adjusted relative risk 0.71, 95% CI 0.52-0.96) and severe mitral regurgitation (adjusted relative risk 2.48, 95% CI 1.0-6.44). There was no statistical difference in LVT rate according to treatment: 21 (7.1%) of 297 patients in the PPCI group, 10 (7.8%) of 128 patients in the thrombolytic group, and 9 (4.1%) of 217 patients in the conservative group (P = .28). Those in the thrombolytic group were characterized by shorter duration from symptom onset and were generally also treated with heparin/low–molecular weight heparin.

This is the largest report to evaluate the incidence of LVT formation after AMI. In the current era of rapid reperfusion by PPCI, the rate of thrombus formation is similar to that reported in the past and not different than for patients currently treated conservatively or with thrombolysis.