Dexter versus Sinister Deep Vein Thrombosis: Which Is the More Sinister? Findings from the NRITLD DVT Registry

Deep vein thrombosis (DVT) is a major health problem. Despite the wealth of studies on its epidemiology, few have described the thrombus sidedness and particularly the association of thrombus sidedness with clinical presentation and subsequent complications. This article reviews current knowledge regarding this topic and in light of recent data from a large prospective study. This is the first report from the prospective National Research Institute of Tuberculosis and Lung Disease DVT registry. Patients with ultrasound-confirmed symptomatic DVT were enrolled, and thrombus sidedness was investigated in each case. Computed tomography pulmonary angiography was used to diagnose coexisting pulmonary embolism (PE) in DVT patients with suggestive symptoms. Embolic burden score was calculated for those with PE. From the total of 100 patients, 45 had left-sided DVT, 41 had right-sided DVT, and 14 had bilateral DVT. Presenting symptoms and comorbidities were comparable, except for cancer, which was more common in those with right-sided involvement (either right-sided or bilateral DVT; P = 0.004). Compared with those with left-sided DVT, PE happened more frequently in right-sided DVT patients. Right-sided DVT patients also had a higher rate of massive PE ( P = 0.03) and a greater mean embolic burden (13.32 ± 1.63 versus 6.05 ± 1.06; P = 0.001). These findings support raised awareness for global reconsideration of the assumption of complete identicalness of right-sided and left-sided DVT. Although future studies are needed to better elucidate epidemiological and prognostic differences based on the thrombus sidedness, our preliminary findings suggest that the two are not completely identical and right-sided DVT might be more ominous.