Angiographic thrombus burden classification in patients with ST-segment elevation myocardial infarction treated with percutaneous coronary intervention.
The presence of thrombus is associated with adverse clinical outcomes. Our aim was to develop a classification of thrombus burden (TB) in patients with ST-segment elevation myocardial infarction (STEMI).


METHODS
We retrospectively analyzed 900 consecutive patients treated with percutaneous coronary intervention for STEMI. Drug-eluting stents were used in 90.1%. TB was graded (G) as G0 = no thrombus, G1 = possible thrombus, G2 = small [greatest dimension ≤ 1/2 vessel diameter (VD)], G3 = moderate (> 1/2 but < 2VD), G4 = large (≥ 2VD), G5 = unable to assess TB due to vessel occlusion. Patients with G5 were reclassified to a thrombus category after flow achievement either with a guidewire or a small (1.5 mm) balloon. The incidence of major adverse cardiac events (MACE) - defined as death, myocardial infarction and infarct-related artery revascularization - was computed using the Kaplan-Meier method.


RESULTS
Median duration of follow-up was 18.5 months. G5 patients constituted 57.7% of all patients and reclassification was achieved in 97.9%. TB after reclassification was G0, 8.1%; G1, 19%; G2, 24.5%, G3,16.6%, G4, 30%, G5, 1.9%. The 2-year cumulative MACE-free survival was comparable in G1, G2, G3 (84.5%, 85.9% and 87% respectively, p = 0.83), while G0 (75.8%) and G4 (75%) did significantly worse (p = 0.001). After stratification in two groups of small (G0-3) and large (G4) TB, the latter was found to be an independent predictor for 2-year mortality (HR: 1.66, 95% CI: 1.04-2.68, p = 0.035) and MACE rate (HR: 2.04, 95% CI: 1.44-2.88, p < 0.001).


CONCLUSIONS
In patients with STEMI, TB can be reliably estimated in occluded infarct-related arteries. Large thrombus (≥ 2 VD) is a significant independent predictor for mortality and MACE.
Sianos
Georgios
G
Department of Cardiology, AHEPA University Hospital, Stilp. Kiriakidi 1, 54636 Thessaloniki, Greece. gsianos@auth.gr
Papafaklis
Michail I
MI
Serruys
Patrick W
PW
D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D003328:Coronary Thrombosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D018572:Disease-Free Survival; D054855:Drug-Eluting Stents; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D012189:Retrospective Studies