Incidence and predictors of left ventricular thrombus by cardiovascular magnetic resonance in acute ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention: a meta-analysis

Abstract

IntroductionThe incidence of left ventricular (LV) thrombus formation in ST-segment elevation myocardial infarction (STEMI) patients in the current era of primary percutaneous coronary intervention (PCI) is not well established. We performed a meta-analysis to assess the actual incidence and predictors of LV thrombus by cardiovascular magnetic resonance (CMR) in STEMI treated by primary PCI.MethodsWe searched MEDLINE and EMBASE databases up to February 2018. We included all studies published as a full-text article, reporting the incidence of LV thrombus by CMR within 1 month following acute STEMI in patients treated by primary PCI. A binary random-effects model was used to estimate the pooled incidence of LV thrombus. The diagnostic performance of transthoracic echocardiography (TTE) as compared with CMR was pooled to obtain the sensitivity and specificity of TTE with CMR as the gold standard. Embolic and bleeding complications of LV thrombus were also evaluated.ResultsTen studies were included in the meta-analysis. The incidence of LV thrombus by CMR in all-comer STEMI patients (n = 2072) was 6.3% with 96% of LV thrombus occurring in those with anterior STEMI (12.2% incidence). When only anterior STEMI with LVEF< 50% were considered (n = 447), the incidence of LV thrombus was 19.2%. Compared with CMR, the sensitivity of TTE to detect LV thrombus was 29% with a specificity of 98%. The sensitivity of TTE increased to 70% in those with anterior STEMI and reduced LVEF. LV thrombus resolved in 88% of cases by 3 to 6 months. After 1–2 years follow-up, the embolic complication rate was similar at 1.5% (P = 0.25) but the bleeding complication rate was significantly higher (8.8% versus 0.5%, P < 0.001) in the LV thrombus group on triple therapy when compared to the no LV thrombus group on dual antiplatelet therapy.ConclusionIn the primary PCI era, CMR detection of an LV thrombus post-STEMI remains high with incidence of nearly 20% in anterior STEMI with depressed LVEF. Patients with LV thrombus treated by triple therapy had similar embolic complications but higher bleeding complications than those with no LV thrombus treated with dual antiplatelet therapy. A 3 month follow-up CMR scan to guide anticoagulation duration might help mitigate bleeding risk.

Role of Cardiac Magnetic Resonance to Improve Risk Prediction following Acute ST-elevation Myocardial Infarction

“…The risk of LV thrombus is highest in patients with anterior infarction and reduced LV ejection fraction. In fact, in the subgroup with anterior STEMI and LV ejection fraction <50%, LV thrombus was described in one in five patients [123]. It is important to note that CMR imaging has a much higher sensitivity for LV thrombus detection when compared with echocardiography [123].…”

“…Formation of LV thrombus post-STEMI is well described and present in approximately 6% of patients undergoing CMR within the first week after the acute event [123]. The risk of LV thrombus is highest in patients with anterior infarction and reduced LV ejection fraction.…”

“…In fact, in the subgroup with anterior STEMI and LV ejection fraction <50%, LV thrombus was described in one in five patients [123]. It is important to note that CMR imaging has a much higher sensitivity for LV thrombus detection when compared with echocardiography [123]. Case examples of patients with and without an LV thrombus are shown in Figure 5.…”

Perfusion cardiovascular magnetic resonance as the first-line technique in patients with stable chest pain

“…[12][13][14][15][16][17][18] Importantly, CMR hugely facilitates identification of complications related to CAD, including thrombus or postinfarction ventricular aneurysm. [19][20][21][22] Accurate detection of the cardiac thrombus is important in patients undergoing stress tests, because safety of such procedure in the presence of thrombus is unknown. 23,24 Perfusion -CMR allows to detect cardiac thrombus with higher sensitivity than transthoracic echocardiography.…”

“…23,24 Perfusion -CMR allows to detect cardiac thrombus with higher sensitivity than transthoracic echocardiography. 20,25 In contrary to dobutamine stress echocardiography, vasodilatators used in perfusion -CMR do not exert positive inotropic effect, which reduces potential risk of thromboembolic complications. Besides, perfusion -CMR with vasodilatators, unlike dobutamine tests, does not cause real ischemia, and thus, adverse effects due to ischemia are avoided.…”