Abstract
            Introduction: In patients with coronary chronic total occlusion (CTO), adequate coronary collateral circulation  (CCC) supports myocardial tissue versus ischemia. Vitamin D deficiency is a risk factor for osteoporosis and other  chronic diseases, including type 1 diabetes, hypertension, metabolic syndrome and ischemic heart disease.  
  Objectives: In this study, we evaluated whether coronary CTO is associated with serum levels of vitamin D and  CCC.  
  Patients and Methods: Around 216 patients with coronary CTO at coronary angiography were incorporated in  this investigation. Serum 25(OH)D level and low-density lipoprotein (LDL-C), triglyceride (TG), total cholesterol,  fasting blood sugar (FBS), serum creatinine, high-density lipoprotein (HDL-C), were assessed before angiography.  Patients were divided into a poor coronary collateral circulation group (Rentrop grades 0-1) or good coronary  collateral circulation group (Rentrop grades 2-3).  
  Results: A total of 216 patients (mean age 61.48±9.5 years) were included in this study. Regression analysis  results displayed that serum 25(OH)D level had a significant correlation with CCC according to Rentrop scoring  system (P<0.0001). We also found that variables such as gender (P=0.05), HDL-C (P=0.01) and serum creatinine  (P=0.05) were a predictor for CCC. This model described 33% of the CCC’s variance in the study patients.  Besides, in the analysis of clinical levels of vitamin D, it can be stated that the probability of having a high degree  of Rentrop criterion in the patients with adequate level of vitamin D is 24.5 times higher than the patients with  vitamin D deficiency (P<0.001).  
  Conclusion: The results of this study emphasize the importance of informing patients with CTO commonly  associated with serum vitamin D level.