Cerebral venous thrombosis at high altitude: more severe symptoms and specific predisposing factors than plain areas

Abstract Background Exposure to high-altitude environment is a risk factor of cerebral venous thrombosis (CVT) probably due to the hypercoagulability. The study aims to explore the unique characteristics of CVT patients in high-altitude areas of China by comparing them with CVT patients in plain areas. Methods We retrospectively included consecutive patients with CVT admitted to Tibet Autonomous Region People’s Hospital (altitude 3650m) and Peking Union Medical College Hospital (altitude 43.5m) between January 2015 and December 2023.The risk factors, clinical and radiological presentations, treatment, and outcomes were analyzed and compared between two groups. Results A total of 169 patients with CVT were included in the study, 48 patients from plateau and 121 patients from plain. The median age was 27 and 34 years old, and women accounted for 66.7% and 54.5% respectively. Headache (91.7% vs. 71.1%, P = 0.004), altered consciousness (31.3% vs. 16.5%, P = 0.033), hemorrhage (41.7% vs. 19.0%, P = 0.002) and venous infarction (50.0% vs. 25.6%, P = 0.002) on imaging were more common in patients from plateau than those from plain. Pregnancy or puerperium was significantly more common in highland patients (25% vs. 5.8%, P < 0.001). The levels of D-Dimer (1.7 vs. 0.8mg/L FEU, P = 0.01), Fbg (3.7 vs. 3.0g/L, P < 0.001), HGB (157 vs. 129g/L, P = 0.01), WBC (9.6 vs. 7.5*1012/L, P < 0.001) and C-reactive protein (20.2 vs. 3.2 mg/L, P = 0.005) were remarkably higher in highland patients. The percentage of receiving anticoagulant therapy was lower in high-altitude patients (70.8% vs. 93.4%, P < 0.001). Favorable outcome at follow-up was observed in 81.4% of highland patients and 90.7% of lowland patients, with the median follow-up time of 330 days and 703 days respectively. Conclusions The more severe clinical and imaging manifestations along with prominent inflammatory and hypercoagulable state were observed in plateau CVT patients, probably due to exposure to the hypoxic environment at high altitude. Pregnancy or puerperium were more common in highland patients. The overall prognosis of CVT patients from both groups were favorable.