The Effect of Collateral Circulation on Myocardial Perfusion during PTCA in Patients with Angina Pectoris

ABSTRACT

BACKGROUND: The coronary collateral circulation has been frequently observed in significant coronary artery disease and its protective role in ischemic myocardium is still remained unclear. But the study on the anti-ischemic effect in human model of ischemic myocardium is rare. METHODS: To observe the anti-ischemic role of coronary collateral circulation in ischemic myocardium, perfusion defect areas were measured during PTCA(percutaneous transluminal coronary angioplasty) in angina patients with single vessel disease and analyzed according to the grade of collateral circulation. The 99mTc-MIBI myocardial scanning images were obtained at 24 hours before PTCA with dipyridamole stress, at ballooning during PTCA and at 24 hours after the opening of the artery and perfusion defect volume ratios(DVR) were measured in each of the images of the patient with angina and single vessel disease. RESULTS: 1) Studied subjects were 14 patients(10 male, 4 female, mean age 56.6+/-103) and subdivided into two groups. All patients had angina with single vessel disease, 7 proximal left anterior descending artery(LAD) stenosis, 4 middle LAD stenosis, 1 middle right coronary artery(RCA) stenosis and 2 proximal left circumflex artery(LCX) stenosis. Group A was composed of 7 patients with angina and coronary collateral circulation more than grade 1. Group B was 7 patients with angina and grade 0 collateral. 2) Mean age of group A was 62.4+/-8.2 years, 5 male and 2 female patients, That of group B was 56.6+/-8.9 years and all male patients. Group A was composed of 7 patients ; 5 unstable and 2 stable angina ; 2 proximal LAD stenosis, 3 midddle LAD stenosis, 1 middle RCA stenosis and 1 proximal LCX stenosis. One patients had grade 1, two patients grade 2 and four patients grade 3 coronary collateral circulation. All of the patients were unstable angina in group B showing 5 proximal LAD stenosis, 1 middle RCA stenosis and 1 proximal LCX stenosis. No collateral circulation was demonstrated in group B. 3) In group A, DVR was 17.5+/-13.9% on stress image before PTCA and 7.1+/-1.4% on the ballooning image during PTCA. DVR was smaller in ballooning image than in stress image(p<0.01). 4) In group B, DVR was 12.4+/-16.0% on stress image before PTCA and 26.6+/-10.0% on ballooning image during PTCA. DVR was larger in ballooning image than in stress image(p<0.001). 5) DVR on stress image and open image were not different in both groups, but DVR on ballooning image were 7.1+/-4.7% in group A and 26.6+/-10.0% in group B, which was larger than in group A(p<0.01). CONCLUSION: These results suggest that myocardial perfusion defect area may be smaller in angina patients with good collateral circulation than patients with no collateral, and coronary collateral circulation have a protective role on the jeopardized myocardium during coronary artery occlusion.