| Objective:In May 2016,the European Society of Cardiology(ESC)proposed the concept of myocardial infarction with non-obstructive coronary arteries(MINOCA)however,the current research on MINOCA is relatively lacking,and the clinical features and Cardiac magnetic resonance(CMR)characteristics of MINOCA patients are not entirely clear.Therefore,the clinical features and the myocardial infarction of CMR characteristics of MINOCA were analyzed,and in contrast to the differences between MINOCA and myocardial infarction with obstructive coronary artery disease(MIC AD),to investigate the difference between MINOCA and MIC AD and the clinical value of CMR multi-parameter imaging in the diagnosis of MINOCA.Ultimately,the goal is to increase awareness of MINOCA,to reduce the number of major heart attacks,and to improve the prognosis.Method:Patients were diagnosed with acute myocardial infarction in the department of Cardiology,Second Affiliated Hospital of Kunming from January 2013 to February 2018,and underwent coronary angiography(CAG)or Coronary computed tomographie angiography(CCTA),according to CAG or CCTA,the results were divided into the MINOCA group and the MICAD group,and the patients had a week to finish CMR,electrocardiogram,cardiocardial enzyme and so on.Cardiac magnetic resonance imaging(CMR)mainly includes cardiac morphological scans,cardiac movie sequences,myocardial perfusion imaging,and delayed-enhanced magnetic resonance,Cardiac functional parameters,myocardial infarct size and myocardial perfusion curves were analyzed by MR cardiac explorer.Cardiac function indexes include left ventricular end-diastolic volume(EDV),left ventricular end-systolic volume(ESV),left ventricular ejection fraction(EF),stroke volume(SV),cardiac index(CI),peak filling rate(PFR),peak ejection rate(PER),and myocardial mass(MM),cardiac output(CO).The study is divided into four parts:(1)The clinical data,heart structure,left ventricular function,myocardial infarction characteristics,myocardial infarction characteristics were compared between the two groups of patients.(2)According to the characteristics of myocardial perfusion image and perfusion curve,MINOCA were divided into perfusion defect,perfusion reduction and perfusion normal segment,and compared with the results of myocardial viability,whether there is level correlation between the grades of different transmural degrees and different types of perfusion were analyzed.(3)According to LGE-MRI results,the left ventricular segment was divided into myocardial infarction segment,no myocardial infarction segment,distribution location and number were statistically analyzed;according to coronary angiography or coronary CTA results,the corresponding relationship between the number of segments and coronary blood supply in the MINOCA group was analyzed,and whether there is difference in myocardial viability results corresponding to mild coronary stenosis and no significant stenosis.(4)In the MINOCA group,LVEF values were compared with myocardial infarct size by Pearson linear correlation analysis;analysis was used to correlate the LVEF value with the number of segments involved in myocardial infarction and myocardial infarction transmural extent score.Results:1.The comparison of general clinical data between 21 patients in the MINOCA group and 30 patients in the MICAD group showed a statistically significant difference in age,smoking history,dyslipidemia,hyperhomocysteinemia,ECG characteristics,and Serum troponin cTnT levels(P<0.05),but the BMI,gender,history of hypertension,history of diabetes,obesity,and family history of coronary heart disease were not statistically significant between the two groups(P>0.05).2.The cardiac structure and function parameters were compared between MINOCA group and MICAD group,the ventricular wall movement and the formation of ventricular aneurysm in the two groups were different.The probability of abnormal ventricular wall motion and the formation of ventricular aneurysm in the MINOCA group were smaller than those in the MICAD group,and had statistical significance(P<0.05);In terms of left ventricular function parameters,the values of LVEF,SV,CO,MM,PER and PFR in group MINOCA were all higher than those in MICAD group(51.85ER and vs 39.90±13.34,56.46±28.82 vs 34.75±13.63,3.726±28.vs 2.30±0.75,109,4628.vs vs 63.38±20.20,2.834628.vs 2.52±0.47,2.514628.vs 2.06±0.55),and the difference was statistically significant(P<0.05).3.Comparing myocardial viability results between the two groups,there were differences myocardial infarct size,number of myocardial infarction involving segments,grade of myocardial infarction transmural score,and transmurality(12.35±8.94 vs 19.88±9.44,4.00±2.05 vs 5.60±2.47,7.90±5.19 vs 14.50±7.66,7/14 vs 20/10),and the difference was statistically significant difference,but the difference in myocardial infarction(anterior/non-anterior wall)was not statistically significant(P>0.05).Compared with group MICAD,the score of infarct area and the degree of permeability of myocardial infarction was smaller in the MINOCA group than that in the MICAD group,and the number of segments and the transmural myocardial infarction were less.4.Of 21 patients in the MINOCA group,coronary CTA or coronary angiography showed that 21 patients had no stenosis of the left main artery(LM),4 patients had no obvious coronary artery stenosis,and mild stenosis-the degree of stenosis less than 50%-occurred in 14 patients the left anterior descending artery(LAD),1 left lateral branches(LCX)and 4 right coronary arteries(RCA);The correlation between the degree of coronary stenosis and the incidence of MINOCA was analyzed by Pearson?2 test.The results showed that there was a difference in the probability of myocardial infarction between the mild coronary stenosis and the non stenosis of the coronary artery(x2=6.652,P=0.01).Compared with no significant coronary stenosis,the probability of MINOCA in the myocardium dominated by mild coronary stenosis was greater(OR=1.924,95%CI=1.165-3.177,P=0.012).The difference of MI probability between LAD and LCX(x2=4.733,P=0.03)was statistically significant,but the difference between LAD and RCA(?2=0.307,P=0.579),LCX and RCA(?2=2.369,P=0.124)was not statistically significant.5.The first-pass perfusion normal segment are 235,the number of reduced perfusion segments are 62,defect segments are 39 in MINOCA group,and Perfusion reduction,their relative peak value of signal intensity are:45.04%±3.35%?32.29%±4.45%and 20.86%±4.45%respectively,the differences of relative peak signal intensity between groups has statistically significant(P<0.01).Kendall's rank correlation analysis was used to analyze the correlation between myocardial perfusion and myocardial infarct size in group N.The grade correlation coefficient ?b was 0.801,P=0.03<0.05.The lower the first perfusion of myocardium,the higher the degree of myocardial infarction transmural.6.Pearson correlation analysis was used to analyze the correlation between LVEF values and myocardial infarct size in the MINOCA group.The correlation coefficient r was-0.819,P<0.001,indicating a negative correlation between cardiac function and myocardial infarct size.Spearman rank correlation analysis was used to correlate the heart function scores with the number of myocardial infarction involving segments and myocardial infarction transmural scores.The correlation coefficients respectively were rs=-0.621 and rs=-0.761,and P was less than 0.01,indicating that heart function and myocardial infarction involving the number of segments,myocardial infarction transmural degree score were negatively correlated.Conclusion:1.Myocardial infarction with non-obstructive coronary artere has certain clinical characteristics;compared with patients with obstructive coronary arterymyocardial infarction,it is younger in age,unusual in dyslipidemia,and more non-ST-elevation myocardial infarction in ECG.2.Compared with the MICAD group,patients in the MINOCA group have smaller myocardial infarct size and transmural degree score,fewer involved segments,and better heart function.3.In the MINOCA group,mild stenosis of the left anterior descending artery(LAD)was common in the three branches of the coronary artery,and the probability of MI in the myocardium dominated by LAD is larger than that of the LCX;.Coronary artery with mild stenosis has greater probability of MINOCA formation than that of the coronary artery without significant stenosis.4.In patients with MINOCA,there is a good correlation between the different myocardial perfusion status and the transmural degree of myocardial infarction detected by LGE.5.In patients with MINOCA,heart function was generally decreased after myocardial infarction,and the larger the area of myocardial infarction,the more number of segments involved,the worse the heart function,which indicated that the size of infarcted myocardium is helpful for predicting cardiac function. |
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