Left Ventricular Thrombi After STEMI in the Primary PCI Era: A Systematic Review and Meta-analysis

Background: Left ventricular (LV) thrombus formation following myocardial infarction (MI) has not been well characterized since the advent of primary percutaneous coronary intervention (pPCI). Ascertainment of the utility of prophylactic anticoagulation is hindered by the lack of reliable information on its modern incidence. We sought to provide an estimate of the rate of LV thrombus formation in patients treated with pPCI for ST segment elevation MI (STEMI) by means of a systematic review and meta-analysis.

Methods: We searched Ovid MEDLINE and Ovid EMBASE databases for studies between 1990 and 2015 documenting LV thrombi after STEMI treated with pPCI. We estimated the rate of echocardiographically-diagnosed LV thrombi within 90days of pPCI, calculating the rate of LV thrombi after STEMI in any infarct territory as well as only anterior infarcts.

Results: From an initial yield of 1144 studies, inclusion criteria were met by 19 studies, including 10,076 patients across 27 centers in 9 countries. Rate of LV thrombi after all STEMI was 2.7% (95% CI 1.9%-3.5%) and 9.1% (95% CI 6.6%-11.6%) after anterior STEMI. Among anterior STEMI, there was an inverse relationship between size of study and rate of LV thrombi.

Conclusions: LV thrombi persist as an important part of the management of STEMI after pPCI, particularly among anterior infarcts. Estimating risk of thrombus formation and embolization as well as utility of treatment remains critical.