Clinical implications of the anatomical variation of deep venous thrombosis.

Introduction Little is known about the anatomic variation and its implication in patients with lower limb deep venous thrombosis (DVT). We studied the clinical presentation, site of thrombosis and risk factors based on the anatomic distribution of lower limb DVT. Methods A retrospective analysis of clinically suspected DVT cases was conducted between 2008 and 2012. DVT was categorized by the location of the thrombosed segment and limb involved. The DVT anatomic segments were assessed according to left-to-right ratio, predisposing factors and clinical presentations. Results A total of 637 patients with DVT were included with a mean age of 50 ± 17 years (51%; females). The most frequently thrombosed segments were popliteal, posterior tibial and profunda femoris veins. DVT was more common at the left side, with a left-to-right ratio of 1.5:1. Bilateral DVT cases (38.5%) had more prior history of DVT as compared to left- (20.3%) and right-sided DVTs (22.6%); p = 0.01. Bilateral DVT was complicated more with post-thrombotic syndrome (leg ulcer) ( p = 0.02). The rates of pulmonary embolism (25%) and mortality (23.1%) were significantly higher for bilateral DVT in comparison to left- and right-sided DVT. Abnormal coagulation profile was significantly associated with posterior tibial DVT (81% vs. 71.4%; p = 0.01) as compared to patients with normal coagulation profile. Conclusion Lower limb DVTs are more common at the left side; however, patients with bilateral DVT have higher frequency of recurrence, post-thrombotic syndrome, pulmonary embolism and mortality. The anatomic segments of DVT show specific distribution depending on the predisposing factors. These findings could improve our understanding of the pathophysiology and management of DVT patients.