Comparison of Carotid Atherosclerosis between Patients at High Altitude and Sea Level: A Chinese Atherosclerosis Risk Evaluation Study

To investigate the differences in characteristics of carotid plaques between patients Xining at high altitude and Jinan at sea level using magnetic resonance (MR) imaging.

Subjects were recruited from a cross-sectional, observational, multicenter imaging study of CARE-II study. Forty-nine (mean age 63.3 ± 12.0 years, 33 males) and 51 (mean age 64.5 ± 12.0 years, 34 males) patients were recruited from a site located in a high altitude region and a site located near sea level, respectively. All patients underwent multicontrast MR vessel wall imaging for carotid arteries on 3.0 T MR scanner. The carotid plaques features were compared between 2 patient groups.

Compared with patients at sea level, those at high altitude had significantly greater lumen area (58.5 ± 17.8 mm² versus 50.0 ± 19.6 mm², P = .008), smaller maximum normalized wall index (48.6% ± 14.2% versus 57.8% ± 16.3%, P = .002), and smaller percentage volume of calcium (0.9% versus 5.6%, P < .001) in the symptomatic carotid artery. After adjustment for clinical risk factors including age, sex, systolic blood pressure, LDL-C, and statin use, these differences in plaque morphology and composition remained statistically significant. After further adjustment for normalized wall index as a measure of plaque burden, percentage volume of calcification was still significantly smaller in patients at high altitude area than that in patients at sea level area (P = .047).

Symptomatic subjects from a high altitude area have lower plaque burden and less calcification in the carotid artery compared to those from an area near sea level.