Thrombosis and Prognosis Following ST-Elevation Myocardial Infarction: Left Ventricular Thrombus Assessment by Cardiac Magnetic Resonance.

Abstract

Acute ST-segment–elevation myocardial infarction (STEMI) is estimated to occur in over 3 million patients each year.1 Left ventricular (LV) thrombus is a serious complication of STEMI, which has been attributed to blood stasis resulting from LV contractile dysfunction and altered geometry (aneurysm). Advances in STEMI management bear particular relevance to LV thrombus: improved coronary reperfusion has augmented myocardial salvage, resulting in improved LV function and remodeling. Newly adopted standard of care therapies, such as thienopyridines, inhibit platelet aggregation, thereby potentially decreasing risk for thrombus. However, despite widespread changes in post-STEMI care, limited data exists concerning LV thrombus in the current era. Given that LV thrombus provides a substrate for embolic events and a rationale for anticoagulation, better understanding of prevalence, predictors, and prognostic significance of post-STEMI LV thrombus is of substantial importance. See Article by Poss et al Beyond changes in clinical management, advances in noninvasive imaging provide a strong rationale for revisiting post-STEMI LV thrombus. Echocardiography (echo) has traditionally been used as the primary modality for evaluating STEMI patients because it is widely available, inexpensive, and supported by ample data demonstrating that echo-based quantification of LV structure and function stratifies post-STEMI prognosis.2,3 However, echo can be limited with respect to LV thrombus. Image quality can be compromised by near field artifacts that obscure the LV apex, a location in which thrombus is often suspected. More broadly, echo limitations may stem from the approach by which thrombus is diagnosed. Echo identifies thrombus based on morphology. This approach can be straightforward when thrombus is large or protuberant, but challenging when thrombus is small or flat (mural). Consistent with these concepts, echo studies have reported marked variability in thrombus prevalence and prognostic significance4,5 and reported substantial inter-reader variability concerning diagnosis of LV thrombus.6 Given …