Angiographic Quantification of Thrombus in ST-Elevation Acute Myocardial Infarction Presenting with an Occluded Infarct-Related Artery and Its Relationship with Results of Percutaneous Intervention

Introduction: Routine thrombectomy has been advocated for ST-segment-elevation myocardial infarction (STEMI), but it is unknown how many patients present with a large thrombus. We aimed to quantify the intracoronary thrombus in STEMI and to correlate it with procedure results.
Methods: In 98 patients with STEMI and TIMI flow grades 0–2 in the infarct-related artery, thrombus was qualified as small (ST) when its maximal dimension was <2 vessel diameters and large (LT) when ≥2. Main outcome measures were TIMI flow, myocardial blush grade (MBG), corrected TIMI frame count (cTFC), and ST-segment elevation resolution (STSER).
Results: Only a third of the patients presented with an LT. Thrombus grade was independent of the initial vessel patency. Diabetes (OR 3.1, 95% CI 1.20–8.02, P = 0.027) and pretreatment with clopidogrel (OR 0.27, 95% CI 0.08–0.86, P = 0.034) were independent predictors of LT. LT was an independent predictor of unfavorable results: <3 TIMI flow (OR 2.87, 95% CI 1.04–8.00, P = 0.043), MBG 0–1 (OR 3.36, 95% CI 1.10–10.26, P = 0.033), cTFC > 21 (OR 2.86, 95% CI 1.09–7.49, P = 0.033) and <50% STSER (OR 3.19, 95% CI 1.06–9.63, P = 0.039).
Conclusion: Only a third of STEMI patients present with an LT, being diabetes and lack of clopidogrel pretreatment independent predictors. An LT is strongly associated with worse PCI results.