The Value Of CK-MB In Risk Stratification And Prediction Of In-hospital Major Adverse Cardiovascular Events Among Patients With Nonst-segment-elevation Myocardial Infarction

Objective: Part of patients who were diagnosed with non-ST-segment-elevation myocardial infarction( NSTEMI) on the basis of serum cardiac troponin I had elevated CK-MB at the same time. Therefore, we aimed to study the value of CK-MB in risk stratification and prediction of in-hospital major adverse cardiovascular events( MACE) among patients with NSTEMI, which the diagnosis standard was on the basis of cardiac troponin I.Methods: The study included a analysis of consecutive NSTEMI patients diagnosed on the basis of cardiac troponin I, who were admitted in the second hospital of Tianjin medical university between January 2015 and January 2016. According to CK-MB level, the object were divided into CK-MB elevated group( elevated group) and CKMB normal group( normal group). Elevated group was defined as the higher one of two collections carrying to test CK-MB( the interval time of 6 to 12 hours) was more than 16 ng/m L, and normal group was defined as the higher one was below 16 ng/m L. The inclusion criteria was: patients who were definitely diagnosed with NSTEMI, which was defined by detection of a rise and( or) fall of cardiac troponin with at least one value above the 99 th percentile of the upper reference level and with at least one of the following situations: symptoms of ischaemia; new or presumed new significant ST-T changes or new left bundle branch block; development of pathological Q waves; imaging evidence of new loss of viable myocardium or new regional wall motion abnormality; identification of an intracoronary thrombus by angiography. The exclusion criteria were: complicated with kidney dysfunction; serious infection, malignant tumor, hematopoietic diseases, thyroid disease or autoimmune diseases; other organic heart diseases except for coronary heart disease, such as rheumatic heart disease, hypertrophic heart diease, dilated heart diease, heart diease caused by thyroid dysfunction, valvular heart dieases, arteritis disease; the existence of dual antiplatelet drug contraindications: cerebrovascular diseases, alimentary tract hemorrhage or major surgeries nearly six months; those patients with incomplete clinical data. All selected patients were collected medical histories in detail, such as high blood pressure, diabet, smoking, stroke and previous history of myocardial infarction. Two blood collections( the interval time of 6 hours to 12 hours) were carried out to test cardiac troponin I and CK-MB. Fasting blood in the next morning was sampled to test biochemical detection, high sensitivity C-reactive protein( hs-CRP) and N-terminal pro-brain natriuretic peptide( NT-pro BNP). Forever, TIMI scores and the modified TIMI( M-TIMI) scores were calculated in all selected patients. The M-TIMI scoring was defined as adding CK-MB to the TIMI score and giving elevated CK-MB level( ≥16ng/m L) 1 point. Additionally, we analyzed the results in those patients who accepted coronary artery angiography.Results: 1. According to two blood collections after admission, the c Tn I levels in elevated group was remarkably higher than that in normal group( p?0.05). That trend was also similar on total white blood cells(( 9.45±6.64 vs. 7.50±2.25)×109/L, P=0.002), neutrophilic granulocyte percentage, absolute monocyte(( 0.50±0.30 vs. 0.42±0.17)×109/L, P=0.009) and hs-CRP( 47.59±68.60 vs. 21.78±34.92, P=0.042). Moreover, compared with normal group, the levels of blood urea nitrogen( 6.98±3.07 vs. 6.09±2.21, P=0.008) and aspartate aminotransferase( 81.45±178.79 vs. 35.59±48.14, P=0.006) were increased in elevated group.2. In the comparison of Killip classes, there was more patients with class Ⅲ( 15 vs. 6,11.4% vs. 4.4%, P=0.042) in elevated group, no pronounced statistic difference in classⅠ, classⅡ, class Ⅳ( p?0.05). The level of NT-pro BNP in elevated group was higher than that in normal group( 1304.5( 360.3, 3231) vs. 601( 83.5, 3979), P=0.045).3. 170 patients performed coronary angiography in current study with 73 cases in elevated group and 97 cases in normal group. Additionally, 166( 97.6%) cases had at least one of the coronary artery stenosis degree more than 70%, and then 46 cases( 27.1%) had at least one totally occluded lesion. The criminal lesion in elevated group was more serious than that in normal group( 0.96±0.07 vs. 0.89±0.21, P=0.002).4. Compared with normal group, the proportion of cardiac death was higher in elevated group( p?0.05). Nevertheless, the following variables did not have statistical significance: acute heart failure, acute stroke, in-hospital MACE( p?0.05).5. Risk factors of MACE were analyzed by multiple logistic regression. The result showed that age, diabetes and Killip class Ⅲ were independent risk factors of inhospital MACE.6. There were no pronounced statistic difference in assessing risk stratification of the two groups by TIMI scores( p?0.05). After using a M-TIMI score, the scores of MTIMI in elevated group was significantly higher than that in normal group in the levels of 5 scores, 6 scores and 7/8 scores( p?0.05). The ROC curve analysis showed that M-TIMI could be as a predictor of in-hospital MACE in patients with NSTEMI( area under the curve=0.589, 95% confidence interval( 0.511, 0.667), P=0.026).Conclusion: NSTEMI patients with elevated CK-MB had more serious criminal lesion and higher in-hospital cardiac death rate than normal ones, which the diagnosis standard was on the basis of cardiac troponin I. Moreover, after CK-MB participating in the risk stratification score system, it is more accurate to assess risk stratification among patients with NSTEMI. Additionally, age, diabetes and Killip class Ⅲ were independent risk factors of in-hospital MACE.