The Adjacent Relationship Between Coronary Artery And Vein In Mitral Valve Isthmus

Purposes: To Study the relationship between coronary artery and vein adjacent to the mitral isthmus,to understand some of the factors affecting the coronary arterial and venous connections in the region,to guide the linear ablation of the mitral isthmus,to improve the success rate of bidirectional block after ablation,and to reduce the radiofrequency catheter ablation complications.Methods: From March 1,2017 to November 20,2017,in the staff hospital of Handan Iron and Steel Group,256-slice spiral coronary computed tomography angiography examinations were performed on 421 suspected coronary heart disease patients(243 males and 178 females).Select the phase with the most clear coronal and venous images to generate the original image of the cross-section.Transfer the original image of the cross-section to a dedicated workstation.Techniques such as the volume rendering(VR),maximum-density projection(MIP),Surface Reconstruction(CPR),and Multi-planar Reconstruction(MPR)are used to reconstruct coronary arterial and venous systems in the workstation.Images are classified into 1-3 levels by quality.The coronary arteries were graded on a scale of 1 to 5 with a curved reconstruction image as the standard.The coronary venous system scored from 0 to 3 points according to the image condition.The observed coronary arteries contain the left coronary artery(including the left main trunk,anterior descending branch,circumflex branch)and the right coronary artery.The coronary venous system included the coronary sinus,the great cardiac vein,the anterior inter-ventricular vein,the posterior inter-ventricular vein(also known as the middle cardiac vein),posterior left ventricular vein,left marginal vein.Measure the length of the endocardial side of the mitral valve isthmus.Observed and recorded the great cardiac vein or coronary sinus and adjacent coronary arteries in the mitral valve isthmus.Observed and recorded the spatial relationship between the great cardiac vein or coronary sinus of the mitral valve isthmus and the adjacent left circumflex coronary,and measured the distance between the great cardiac vein or coronary sinus and the left coronary circumflex branch.Results: 243 male(57.7%)and 178 female(42.3%)patients were studied.Their age is from 26 to 82 years old and the average age is(59.46±10.81)years old.There were 34 young people(8.1%),middle-aged patients aged from 45 to 60,and 144 elderly patients(34.2%)over 65 among them.There were 90 patients(21.4%)with atherosclerotic stenosis less than 30%,183 patients(43.5%)with coronary atherosclerotic stenosis greater than or equal to 30% and less than 50%,there were 148 patients(35.1%)with atherosclerotic stenosis greater than or equal to 50%.In 421 patients,the Coronary computed tomography angiography image quality was Grade 1 or Grade 2,and arterial scores were greater than or equal to 3,and venous scores were greater than or equal to 2 points.The left coronary artery(left main trunk,left anterior descending artery,and left circumflex artery)and right coronary artery showed a 100% rate in the coronary system;the coronary sinus,great cardiac vein,anterior inter-ventricular vein,posterior inter-ventricular vein(or middle cardiac vein)display rate was 100%;the total display rate of the left ventricle posterior vein or left border vein was 75.1%.In the coronary computed tomography angiography images of 421 patients,the length of the mitral valve isthmus(MI)was(21.8-63)mm,and the average length was(38.7 ± 8.1)mm;there are three adjacent relationships between the arterial and the venous regions of the mitral valve isthmus: the left circumflex coronary artery(LCX)and the great cardiac vein-coronary sinus(GCV-CS)adjoining 97.6%(411/421),right coronary artery(RCA)and GCV-CS adjoining 1.7%(7/421),GCV-CS without LCX or RCA accounted for 0.7%(3/421).LCX and GCV-CS are adjacent to arterial veins that are mainly adjacent in the mitral isthmus area.There are four spatial relationships in the 411 adjacent LCX and GCV / CS relationships: GCV-CS and LCX in epicardial side of MI accounted for 51.6%(212/411),the LCX is located between the GCV/ CS and the mitral valve isthmus accounting for 19.0%(78/411),GCV / CS is located between mitral isthmus and LCX accounting for 6.8%(28/411),GCV-CS arrayed on the epicardium side of MI and LCX arrayed on the same side of the left ventricle epicardium was 22.6%(93/411).There was no significant difference in the spatial distribution of LCX adjacent to GCV-CS in the mitral valve isthmus in patients of different genders,ages,and coronary atherosclerotic stenosis.The distance between LCX and GCV-CS measured in the mitral valve isthmus was(0.2-23.5)mm,with an average of(2.75±2.38)mm.There was no significant difference in the distance between LCX and GCV-CS in people of different genders,ages,and different degrees of coronary atherosclerosis.In the different adjacent spatial distributions of LCX and GCV-CS,there was a significant difference in the distance between LCX and GCV-CS.Conclusions: The 256-slice coronary computed tomography angiography clearly showed the spatial relationship between coronary arteries,veins,and coronary arteries and veins and adjacent tissue structures.LCX and GCV-CS are the most common adjacent arteries and veins in the mitral isthmus area.In different degrees of coronary atherosclerosis,there was a significant difference in the distance between LCX and GCV-CS.In the different adjacent spatial distributions of LCX and GCV-CS,there was a significant difference in the distance between LCX and GCV-CS.It has important clinical significance in guiding the linear ablation of the mitral valve isthmus,improving the success rate of bidirectional block after ablation,and reducing the complications of radiofrequency catheter ablation.