Prevalence and Clinical Characteristics of Post-Thrombotic Syndrome in High-Altitude-Induced Deep Vein Thrombosis: Experience of a Single Tertiary Care Center from Real-World Settings.

Uday, Yanamandra, Revanth Boddu, Suman Pramanik, Kundan Mishra, Rajan Kapoor, Ankur Ahuja, Tathagata Chatterjee, and Satyaranjan Das. Prevalence and clinical characteristics of post-thrombotic syndrome in high-altitude-induced deep vein thrombosis: experience of a single tertiary care center from real-world settings. High Alt Med Biol. 00:000-000, 2020. Background: Exposure to high altitude (HA) is a recognized predisposing factor for venous thrombosis. Post-thrombotic syndrome (PTS) is a significant late complication, occurring in ∼30%-50% of patients of deep vein thrombosis (DVT). There are not many studies about the characteristics of PTS in patients with HA-DVT. Aim: The aim was to study the epidemiology and clinical characteristics of PTS using a noninvasive Villalta score and identify the risk factors for its development in patients with HA-DVT. Methodology: This is a retrospective single-center observational study (n = 47). The diagnosis of HA-DVT was confirmed using color Doppler ultrasonography at HA. The patients were managed with low molecular weight heparin, followed by vitamin K antagonist therapy till normalization of D-dimer and imaging. The therapeutic target range of >80% was ensured. Villalta scale was used for PTS assessment. JMP 15.0 was used for statistical analysis. Results: All study participants were male with a median age of 34 years, of which 46.81% developed PTS with mean Villalta of 5.29 ± 4.25. The most common symptom was pain (87.23%; n = 41), whereas the most common sign was hyperpigmentation (42.5%; n = 20). On multivariate analysis, the time from onset of DVT and the extent of DVT were related to the development of PTS (degree of freedom [dF] = 5, χ2 = 17.34, p = 0.0039) with a likelihood ratio of 4.95 (p = 0.026) and 4.96 (p = 0.026), respectively. The extent of DVT was associated with the severity of PTS (dF = 5, χ2 = 12.6, p = 0.0273) with a likelihood ratio of 5.24 (p = 0.022). Conclusions: PTS develops in approximately half of the patients with HA-DVT. The extent of DVT is a significant risk factor for both development of PTS and its severity, whereas time to assessment of PTS from the onset of DVT was associated only with the occurrence of PTS.