Impact of altitude environment on coronary artery calcification: comparative analysis in ecuadorian populations using coronary calcium score

Background Coronary artery calcification is a marker of atherosclerosis and a predictor of cardiovascular events. In recent years, the influence of non-traditional cardiovascular risk factors, called exposome, has gained relevance in the pathogenesis of cardiovascular disease. Moreover, chronic exposure to hypoxia at high altitudes generates cardiovascular adaptations, including systemic hypertension, pulmonary hypertension, and cardiac remodeling. However, its impact on coronary atherosclerosis has not been clearly established. This study aimed to compare coronary atherosclerotic plaque burden measured by coronary calcium scoring (CCS) by computed tomography (CT), between populations that permanently reside at sea level and at high altitudes in Ecuador. Methods Patients from three cities were included in the analysis: Guayaquil (sea level), Cuenca (2550m), and Quito (2850m above sea level). CCS was performed in three institutions of these cities and was acquired with the recommended protocols, quantifyin in Agatston units (AU). Results A total of 327 patients were included; the mean age was 62.9 years, and 40.3% were women. The main cardiovascular risk factors were arterial hypertension (58%), overweight/obesity, type 2 diabetes (17.4%), and dyslipidemia. 36.3% of the participants were under treatment with statins. Table 1 summarizes the baseline characteristics of the population, according to their city of origin. Populations at sea level had significantly lower values of total cholesterol, HDL-c, and LDL-c compared to higher altitude regions (Table 1). However, residents living at sea level had significantly more calcification in all coronary areas except the left main coronary artery territory (Table 2). The greatest variation was observed at the circumflex artery level among residents of Guayaquil, Cuenca, and Quito (SCC 69.1 ±223 versus 20.5 ±103.7 and 15.6 ±62; p=0.008 respectively) (Table 2). A zero coronary artery calcium score was found more frequently in patients living in high-altitude environments compared to sea level. Nevertheless, there were no significant differences between groups (SLR: 47.5% vs 2550mts: 58.9% vs 2850mts: 50%, p:0.3) Conclusions Our data suggest that living at high altitudes was not associated with a higher coronary atherosclerotic plaque burden, as measured by CCS. The higher coronary calcification in individuals at sea level, despite similar clinical characteristics, and even lower lipid levels, suggests the influence of other environmental and/or genetic factors. Therefore, further studies are needed to clarify the influence of altitude on the development of coronary atherosclerosis.Characteristics of total population SCC in different coronary arteries