The Diagnosis Value Of LM-LAD Bifurcation And Tortuosity For Evaluation Of Bifurcation Lesions By Dual Source CCTA

ObjectiveTo evaluate the value of dual-source coronary CT angiography in assessment of bifurcation lesions by measuring the LM-LAD angle and tortuosity.Materials and Methods1.Clinical data:A total of 300 patients with suspected or confirmed coronary heart disease from October 2016 to January 2018 in Linfen City People’s Hospital were selected,and a total of 88 patients were treated with coronary artery CT angiography(CCTA)and invasive coronary angiography(CAG)and conformed to the inclusion criteria.2.Coronary CTA examination:Coronary CT angiography was performed on a dual-source CT(DSCT)scanner(Siemens Somatom Definition flash).The patient underwent respiratory training to confirm that all patients held breath time not less than 20s.Patients with heart rates>90 beats/min were administered metoprolol(dose reference product instruction)one hour before the scan for droping to 70 beats/min and 0.5 mg of sublingual nitroglycerin 1 minutes prior to the CT scan.An intravenous channel was established in the anterior cubital vein and a 18 G trocar was placed for injection of iopromide nonionic contrast agent(370 mgI/ml)in a dose of 60~70 ml at a flow rate of 4~6 ml/s.The subjects took a supine position,raised their hands and advanced their feet.The scanning was carried out one by one according to the sequence of location,calcification and CTA imaging.During the examination,the patients’ECG,heart rate,blood pressure,clinical symptoms and other indexes were monitored throughout the course.After the examination,the observation was left after half an hour.3.Coronary angiography(CAG)examination:Invasive coronary angiography(CAG)was performed on the PHILPS digital X-ray angiography machine(PHILIPS,Allura Xper FD10).The patient is in supine position.After 1%lidocaine local anesthesia,the Seldinger method was used to place the sheath through the radial artery and then heparin 3000u was injected.Different postures were used to visualize the plaque in the left coronary bifurcation.4.Image Analysis:The CCTA image was analyzed by 2 senior medical imaging diagnostics(deputy chief physician).The LM-LAD angle and the tortuosity of the coronary artery were measured in 88 patients,and the stenosis of the lumen was measured by CTA diameter method.88 patients were divided into bifurcation lesions and non-bifurcation lesions with the stenosis of the left coronary artery bifurcated at or above 50%.5.Statistical analysis:Using statistical analysis software SPSS 20.0.Independent sample t-test was used to analyze the measurement data of LM-LAD bifurcation angle,tortuosity and patient’s age.χ~2test was used to analyze the count data of patients’gender,body mass index,blood pressure,blood lipid,blood sugar,smoking,drinking and family history.Receiver operating characteristic(ROC)curves were used to analyze the diagnostic value of LM-LAD angle and LM-LAD tortuosity of bifurcation lesions.P<0.05for the difference was statistically significant.Results1.CAG as the gold standard,dual-source CT coronary angiography through the measurement of lumen stenosis assessed bifurcation lesion with a sensitivity of 80.0%,specificity of 81.6%,positive predictive value of 85.1%,negative predictive value of75.6%,and Youden index of 0.61.2.There was no significant difference in the LM-LAD angle between the bifurcation lesion group and the non-bifurcation lesion group.Using ROC curve,LM-LAD angle assessed bifurcation lesion with a sensitivity of 56.0%,specificity of 60.5%,the positive predictive value of 65.1%,the negative predictive value of 51.1%,and Youden index of0.17.3.The LM-LAD tortuosity in the bifurcation lesion group was significantly greater than that of the non bifurcation lesion group.In the ROC curve analysis,LM-LAD tortuosity assessed bifurcation lesion with a sensitivity of 76.0%,specificity of 92.1%,the positive predictive value of 92.7%,the negative predictive value of 74.5%,and Youden index of 0.68.4.The measurement of lumen stenosis combine with the LM-LAD tortuosity assessed bifurcation lesion with a sensitivity of 54%,specificity of 97.4%,positive predictive value of 96.4%,and negative predictive value of 61.7%,Youden index of 0.51.5.The measurement of lumen stenosis combine with the LM-LAD angle assessed bifurcation lesion with a sensitivity of 24.0%,specificity of 92.1%,positive predictive value of 80.0%,and negative predictive value of 47.9%,Youden index of 0.16.Conclusions1.The clinical value of left coronary artery LM-LAD angle in evaluating bifurcation lesions is limited.2.The left coronary artery LM-LAD tortuosity and bifurcation lesions has certain correlation,ie,the greater tortuosity suggests possible bifurcation lesions.3.Compared with a single measurement of luminal diameter,combined LM-LAD tortuosity measurement can significantly improve the detection accuracy and diagnostic value of CCTA for bifurcation lesions;combined LM-LAD angle measurement is not superior to a single luminal diameter measurement in diagnosing bifurcation lesions.