Intracoronary Thrombus Types Of Patients With ST-segment Elevation Myocardial Infarction

Research background Rupture of vulnerable plaque with subsequent thrombus formation is the mainly pathogenesis of acute myocardial infarction.Pathological and imaging studies have demonstrated that thrombus in coronary artery can be classified as red and white thrombus.The traditional paradigm is that the type of thrombus in patients with ST-segment elevation myocardial infarction(STEMI)is red.However,Yasushi used Optical Coherence tomography(OCT)to analyse the culprit lesion of 40 patients with STEMI and found that 78% of the thrombus in STEMI were red and 22% were white.Quadros et al distinguished aspirated intracoronary thrombus by macroscopy and reported that white thrombi were present in about one-third of STEMI patients.Since pathological analysis is the golden standand of differentiating thrombus and thrombus aspiration has enabled us to acquire intracoronary thrombus economically and conveniently,we want to identify whether there are different types of aspirated thrombus in patients with STEMI.Objective The aim of this study was to investigate the types and constituent ratio of thrombus aspirated from patients with STEMI;to study the associated factors related with thrombus type in patients with STEMI.Method STEMI patients within 12 hours of symptom onset undergoing primary percutaneous coronary intervention in Henan Provincial People’s Hospital were included.The study period for enrollment was from March 2014 to February 2016.All of the patients accepted thrombus aspiration.Both macropathological and histopathological analysis were observed on the aspirated thrombus.Thrombus materials were classified as red/mixed or white thrombus based on the histopathological constitute.The clinical baselines,angiographic characteristics and macropatholgy of thrombus were compared between the two groups.Univariate and multivariate Logistic regression were made to study the associated factors related with thrombus type in patients with STEMI.Results137 patients undergoing primary percutaneous coronary intervention were included in this study.Thrombus aspiration was performed among the participants.The pathology analysis can be retained in 97 patients,including 64 cases(66%)with red/mixed thrombus and 33 cases(34%)with white thrombus.More patients tended to be smokers in the red/mixed thrombus group than the control group(P=0.031).The total ischeamic time was significantly longer in red/mixed thrombus group compared with that in white thrombus group(p=0.013).The white thrombus group had more patients with coronary collateral circulation than that in the red/mixed thrombus group(p=0.001).The histopathogy verified red/mixed thrombus tended to be grey-red in colour and strip in shape;while the white thrombus tended to be grey-white in colour and fagment in shape.The diameter(P<0.001)and length(P=0.001)of red/mixed thrombus were significantly longer than that of white thrombus.Multi-variable logistic analysis showed that total ischemic time and coronary collateral circulation were predictors for thrombus constitute.Total ischemic time was a risk factor for red/mixed thrombus(Odds ratio: 1.741 [95% confidence interval:1.203 to 2.520];P=0.003);while coronary collateral circulation was a protecting factor for red/mixed thrombus(Odds ratio: 0.109[95% CI,0.032 to 0.376];P <0.001).Conclusion Red/mixed thrombi were present in nearly two-third of STEMI patients;while white thrombi account for one-third of the cases.The ischemic period and coronay collateral circulation were related with the thrombus constitute.The possibility of red/mixed thrombi increased with the extention of ischemic time;red/mixed thrombi tender to be in patients without coronary collateral circulation while white thrombi tended to be in patients with coronay collateral circulation.