The combination of creatine kinase-myocardial band isoenzyme and point-of-care cardiac troponin/contemporary cardiac troponin for the early diagnosis of acute myocardial infarction

BACKGROUND:The early diagnosis of acute myocardial infarction(AMI)remains challenging,especially for institutions without the high-sensitive cardiac troponin(hs-c Tn)assay.Herein,we aim to assess the value of creatine kinase-myocardial band isoenzyme(CK-MB)combined with different cardiac troponin(c Tn)assays in AMI diagnosis.METHODS:This multicenter,observational study included 3,706 patients with acute chest pain from September 1,2015,to September 30,2017.We classified the participants into three groups according to the c Tn assays:the point-of-care c Tn(POC-c Tn)group,the contemporary c Tn(c-c Tn)group,and hs-c Tn group.The diagnostic value was quantified using sensitivity and the area under the curve(AUC).RESULTS:Compared to the single POC-c Tn/c-c Tn assays,combining CK-MB and POC-c Tn/c-c Tn increased the diagnostic sensitivity of AMI(56.1%vs.63.9%,P<0.001;82.7%vs.84.3%,P=0.025).In contrast,combining CK-MB and hs-c Tn did not change the sensitivity compared with hs-c Tn alone(95.0%vs.95.0%,P>0.999).In the subgroup analysis,the sensitivity of combining CKMB and c-c Tn increased with time from symptom onset<6 h compared with c-c Tn alone(72.8%vs.75.0%,P=0.046),while the sensitivity did not increase with time from symptom onset>6 h(97.5%vs.98.3%,P=0.317).The AUC of the combination of CK-MB and POC-c Tn significantly increased compared to the single POC-c Tn assay(0.776 vs.0.750,P=0.002).The AUC of the combined CKMB and c-c Tn/hs-c Tn assays did not significantly decrease compared with that of the single c-c Tn/hs-c Tn assays within 6 h.CONCLUSIONS:The combination of CK-MB and POC-c Tn or c-c Tn may be valuable for the early diagnosis of AMI,especially when hs-c Tn is not available.