Association Between Coronary Collaterals And Myocardial Viability In Patients With A Chronic Total Occlusion And Its Effect On Prognosis Of Percutaneous Coronary Intervention

Objective: To investigate the relationship between collateral circulation evaluated by coronary angiography and viable myocardium assessed by PET in patients with CTO.And to analyze its impact on prognosis of PCI.Methods: Patients diagnosed with CTO confirmed by coronary angiography and undergoing myocardial perfusion/metabolic imaging during hospitalization at the Department of Cardiology,The People’s Hospital of Liaoning Province from December2018 to June 2020 were included.Patients with CTO included in the study were grouped by combining the Werner CC grading and rentrop grading methods.Among them,CC grade 2 and Rentrop grade 3 were classified as the group with well-developed collateral circulation(WDC),and CC grade 0-1 or Rentrop grade 0-2 as the group with poorly-developed collateral circulation(PDC).The parameters of viable myocardium and left ventricle ejection fraction were compared among different groups.And their effects on the patients’ percutaneous coronary interventions were compared.We also analyzed the effects of different collateral circulation and viable myocardium on patients’ Seattle angina score(SAQ)and recovery of cardiac function after PCI.Results: A total of 55 patients were included in the study,including 27 in the group with well-developed collateral circulation and 28 in the group with poorly-developed collateral circulation,and the baseline data of the two groups were not statistically different and were comparable.The left ventricular ejection fraction was higher in the WDC group compared to the PDC group [(50.04±9.28)% vs.(47.14±5.89)%,P>0.05],and the number of viable myocardium was higher in the WDC group compared to the PDC group [(16.07±7.91)% vs.(12.89±6.93)%,P>0.05],all differences were not statistically significant.The success rate of PCI was 96.3% in the WDC group and 75.0%in the PDC group and the difference was statistically significant.There was no significant correlation between the grade of collateral circulation and the recovery of cardiac function after PCI in patients.Patients with ≥10% viable myocardium had a statistically significant improvement in cardiac function 6 months after PCI compared with before.SAQ scores were higher in all subgroups of patients than before PCI,and the difference was statistically significant.Conclusion: In patients with CTO,well-developed collateral circulation is more favorable for patients treated with PCI,and there is no significant correlation between the grade of collateral circulation and the number of viable myocardium.recovery of cardiac function after PCI in patients with CTO is related to the number of viable myocardium.