Relationship Between Serum Lipoprotein(a) Level And Microvascular Angina

Objective:To discuss the correlation between serum lipoprotein（a）[Lp（a）]and microvascular angina（MVA）,so as to guide clinical intervention.Methods:35 patients with exertional angina pectoris,whose electrocardiogram showed Ischemic ST-T changes,coronary arteriography（CAG）or coronary artery CT angiography（CTA）showed no obvious coronary artery stenosis（one or more major coronary artery stenosis<50 persent）,including 12 males and 23 females,who were admitted to The People’s Hospital of Liaoning Provincial from January 2019 to October2020.The average age was（55.3±8.5）years.All patients were examined by TTDE.The collected TTDE parameters included the diastolic mean blood flow velocity peak of（LAD）in resting state and the diastolic mean blood flow velocity peak value of LAD in loading state（intravenous injection of adenosine）.The ratio of the latter to the former was used to reflect CFR.The patients were divided into MVA group（n=21）and control group（n=14）according to CFR<2.0.Collect baseline clinical data of all patients in the group:including age,sex,body mass index,etc.The laboratory indexes including serum lipoprotein（a）[Lp（a）],total cholesterol,high density lipoprotein cholesterol and low density lipoprotein cholesterol were collected.SPSS 25.0 was used as the statistical software in this study.The measurement data were expressed as mean±standard deviation（（?）±s）（consistent with normal distribution）or median（non normal distribution）.The comparison between groups was performed by t test or Mann Whitney U test.The count data was expressed as percentage（%）.The comparison between groups was performed byχ²test or Fisher test.Pearson test Correlation analysis of the factors affecting CFR,and multiple stepwise regression analysis of the salient element influencing CFR.Drawing the receiver operating characteristic curve to evaluate the predictive value of Lp（a）on MVA,P<0.05 that the difference was statistically significant.Results:1.Comparison of baseline clinical data:The age of the MVA group was higher than that of the control group（53,65）vs（43,56）,P=0.013,the difference was statistically significant（P<0.05^*）,while the gender between the two groups（P=1.000）History of diabetes（P=0.486）,history of hypertension（P=0.486）,history of smoking（P=0.884）,history of drinking（P=0.863）,BMI（23.77±2.66）vs（25.45±2.31）,P=0.056,The difference is not statistically significant（P>0.05）2.Comparison of laboratory indicators:serum Lp（a）444.45（212.9,571）mg/L, serum HDL-C1.07（1.04,1.45）mmol/L,and serum TC（4.46±1.11）mmol/L in MVA group were all higher than The control group 68.20（42.35,204.23）mg/L,0.88（0.84,1.07）mmol/L,（3.58±0.97）mmol/L,the difference was statistically significant（P<0.05^*）,the serum Lp（a）in the MVA group)Value was significantly higher than the control group,the difference was significant(P<0.001^**),the serum TG level between the two groups was 1.18（0.83,2.06）vs 1.11（0.66,1.58）mmol/L,P=0.578,serum LDL-C（2.79±0.76）vs（2.19±0.46）mmol/L,P=0.133,the difference is not statistically significant（P>0.05）3.Correlation analysis between CFR value and baseline clinical data:CFR value is negatively correlated with age(r=-0.614,P<0.001^**),and related to smoking history（r=-0.947,P=0.012^*）;while CFR value There was no correlation with gender（P=0.775）,history of diabetes（P=0.312）,history of hypertension（P=0.775）,history of drinking（P=0.810）,and BMI（P=0.219）.4.Correlation analysis between CFR value and laboratory indicators:CFR value is negatively correlated with Lp（a）,HDL-C,and TC(r=-0.814,P<0.001^**;r=-0.347,P=0.027^*;r=-0.350,P=0.039^*),and the CFR value has no correlation with TG（P=0.963）and LDL-C（P=0.360）.5.Stepwise multiple regression analysis of CFR value:Taking CFR as the dependent variable,age,Lp（a）,LDL-C,HDL-C,TC as independent variables,stepwise multiple regression analysis was performed,and the results showed that plasma age（r=-0.325）,P=0.041^*),Lp（a）(r=-0.486,P=0.003^**),LDL-C（r=-0.415,P=0.010^*）are the main factors affecting the CFR value.There was no significant correlation between plasma HDL-C（r=0.022,P=0.850）,TC（r=-0.061,P=0.547）and CFR.6.Predictive analysis of lipoprotein（a）on MVA:Draw ROC curve,get the area under the curve of Lp（a）to predict MVA respectively:0.884[95%CI（0.743,0.994）],the best cut-off value is 488.85 mg,respectively/L,the sensitivity is 85.7%,and the specificity is 85.7%.Conclusion:1.Age,serum Lp（a）are risk factors for MVA2.Serum Lp（a）has a good predictive value for MVA.When serum Lp（a）is greater than 488.85 mg/L,MVA may be considered.