Evaluation of Risk Factors in Individuals with Vascular Thrombosis at High Altitude

Abstract

Objective: To evaluate the risk factors for developing vascular thrombosis at high altitude. Study Design: Prospective longitudinal study. Place and Duration of Study: Combined Military Hospital, Skardu Pakistan, from Mar 2018 to Feb 2020. Methodology: All individuals evacuated from high altitude with suspicion of vascular thrombosis were consecutively inducted and evaluated radiologically. Subjects diagnosed as VT were further categorized on basis of height of evacuation into high altitude, very high altitude and extremely high altitude categories. Results: Out of 295 individuals evacuated from HA, 54(18.3%) were diagnosed as VT. All patients were males. Mean age was 31+5.3 years. Cerebral venous thrombosis was diagnosed in 19(35%) and was the most frequent followed by pulmonary embolism in 18(33%) and deep venous thrombosis in 14(26%) patients. Risk of VT increased with increase in altitude as 05(10%) cases were from high altitude, 18(33%) were from very high altitude and 31(57%) from extremely high altitude. VT was more frequent in smokers [36 cases (67%), p<0.05] and in cold weather (37 cases (69%), p<0.05). Duration of stay has significant inverse correlation with height of deployment (r= -0.592, p< 0.001). Significant difference was found in duration of stay (p<0.001), haemoglobin (p=0.016) and haematocrit (p=0.012) among different categories of high altitude. Conclusion: Cases of vascular thrombosis increase with increasing altitude even in shorter period of stay. Increasing haemoglobin and haematocrit with increase in altitude, cold environmental temperature and smoking are important risk factors for development of VT.

Keywords

• Altitude, Embolism, Haemoglobin, Haematocrit veinous thrombosis