The Analysis Of CK-MB And CTnI Accordance Measured On Admission And Related Clinical Features In 1074 Acute Coronary Syndrome Patients

ObjectiveACS (Acute Coronary Syndrome) is an important subtype of CHD(Coronary Heart Disease). It is composed of UAP (Unstable AnginaPectoris), NSTE-MI (non ST segment Elevation Myocardial Infarction),and STE-MI (ST segment Elevation Myocardial Infarction), and theproportion of each component is 12.86%, 66.14%, 21.00% respectively.UAP and NSTE-MI are also called NSTE-ACS (non ST segment ElevationAcute Coronary Syndrome). The main mechanism of ACS is rupture orerosion of the unstable atherosclerotic plaque and thereby incompleteocclusion of the coronary artery by thrombosis. The pathologicalevolution of UAP is uncertain, which can either develop into AMI or runto stable angina pectoris (SAP). Evaluation of the risks in ACS patientsand early initiation of proper therapy is very important for ameliorationof clinical outcome. The purpose of present study is to evaluate theassociation between markers of cardiac injury and early coronaryangiography results, in-hospital myocardial infarction, cardiac death,revascularization and treatment patterns in patients with NSTE-ACS, andto provide a rationale for the interpretation of double detection of cardiacbiomarkers in clinical settings.Methods1074 NSTE-ACS patients admitted in the division of cardiology,Medical College Affiliated Hospital of Chinese People's Armed PoliceForces (CPAPF) during Apr, 2004～Jul 2007, whose CK-MB and cTnI were measured within the first 36 hours from symptom onset afteradmission, were enrolled in the present study. All patients receivedcoronary angiography within 48h. Positive results were recorded ifbiomarker＞1×upper limit of normal (ULN), and negative result wasrecorded when biomarker≤1×ULN.1. We examined relationships between results of four markercombinations (CK-MB~-/cTnI~-, CK-MB~+/cTnI~-, CK-MB~-/cTnI~+, andCK-MB~+/cTnI~+) and incidences of in-hospital myocardial infarction,cardiac death and early catheter-based interventions.2. All patients were assigned to cTnI~+ group and cTnI~- groupaccording to level of cTnI. We examined the relationships between cTnIlevel with demographic and clinical data and incidence of in-hospitalmyocardial infarction, cardiac death and early catheter-basedinterventions.3. All patients were re-analyzed according to the results of CK-MB.4. We analyzed the data in CK-MB~+/cTnI~- group and CK-MB~-/cTnI~+group, and evaluated their roles in risk stratification of NSTE-ACS.5. In another subset of analysis, patients with renal dysfunction(Cr＞132μmol/L) were all excluded. Then we reevaluated the data in fourgroups, in order to identify the impact of slight renal functioninsufficiency on the level of cardiac biomarkers.Results1. Among 1074 NSTE-ACS patients, 318 were cTnI~+, and 356 wereCK-MB~+. Results from 930 patients were accordant in CK-MB and cTnIlevel, and the other 144 were discordant (n=90 [8.38%] CK-MB~+/cTnI~-;n=54 [5.03%] CK-MB~-/cTnI~+).2. The incidences of stroke(P=0.008), proteinuria(P=0.006),WBC(White Blood Corpuscle)count(P=0.01), number of damagedcoronary artery(2, P=0.018; 3, P=0.002), SCAI(Society for CardiacAngiography and Interventions)typeⅡ(P＜0.001),Ⅲ(P=0.001) and Ⅳ(P＜0.001) coronary artery damage and MACE (Main Adverse CardiacEvent) were higher in cTnI~+ group regardless the level of CK-MB.3. Except for the incidence of MACE (P=0.201), similarly resultswere observed from CK-MB group regardless the level of cTnI.4. The number and types of damaged coronary artery and theincidence of MACE did not have statistical difference between theCK-MB~-/cTnI~+ and CK-MB~+/cTnI~- group.5. WBC count was found effective in risk stratification, whetherpatients were grouped by cTnI or by CK-MB.Conclusions1. Elevation of cTnI alone can predict a higher risk of NSTE-ACSpatients.2. Prognostic value of isolated CK-MB~+ is equal to isolated cTnI~+when the tests performed early after admission (＜36h).3. cTnI is considered as both a biomarker of cardiac injury and anindex for the severity of left ventricular systolic function.4. Poor coronary angiographic and prognostic results seem to beassociated with elevated cTnI level and increased incidence of MACE.5. The relationship between proteinuria and elevated level of cTnI isstill not very clear. Slight renal dysfunction does not affect the result ofcTnI in MI.6. WBC count is of clinical importance in risk stratification of ACSpatients.Recognition of these risk differences may contribute to moreappropriate early use of antithrombotic therapy and invasive managementfor all cTn~+ patients.