Association between coronary chronic total occlusion and living in extreme natural and climatic conditions

Aim . To study the relationship between coronary chronic total occlusion (CTO) and living in extreme natural and climatic conditions of the Far North in patients with coronary artery disease (CAD). Material and methods . A total of 5679 patients with coronary artery disease (CAD) were selected from the "Registry of Coronary Angiography Operations". The main group consisted of 2588 non-native residents of the Far North, while the comparison group — 3091 patients living in the south of the Tyumen Oblast. CTO was defined as the absence of antegrade coronary flow for more than 3 months according to the medical history or previous coronary angiography. In order to eliminate the initial imbalance between the study groups, the propensity score matching method was used. Results . Patients living in the Far North were younger (53,2±7,49 years vs 56,8±8,34 years, p<0,001), and were more often men. After propensity score matching, in groups balanced by the main risk factors for CAD, Far North patients were more likely to have significant coronary atherosclerosis. At the same time, CTO was significantly more often determined in patients permanently residing in the Far North (50,3% vs 41,7%, p<0,001). In patients of the main group, CTO was more often located in the proximal (35,0% vs 29,0%, p<0,001) and middle coronary segments (39,0% vs 33,0%, p<0,001) in comparison with the group of the South of the Tyumen Region. The most frequent occlusion location was determined in the anterior descending artery (22,0% vs 17,0%, p<0,001) and the right coronary artery (28,0% vs 24,0%, p=0,001). According to multivariate analysis, residence in the Far North was associated with an increase in detection rate of CTO during coronary angiography by 39% (odds ratio 1,39; 95% confidence interval: 1,25-1,54; p<0,001). Conclusion . CTO is more common in patients with CAD living in the Far North compared to patients living in the South of the Tyumen Region. According to multivariate analysis, living in extreme natural and climatic conditions was an independent predictor of CTO according to coronary angiography.