Prevalence and Risk Factors of Asymptomatic Lower Extremity Deep Venous Thrombosis in Asian Neurorehabilitation Admissions in Singapore

Chua K, Kong KH, Chan SP. Prevalence and risk factors of asymptomatic lower extremity deep venous thrombosis in Asian neurorehabilitation admissions in Singapore.ObjectiveTo determine the local prevalence and risk factors of asymptomatic lower limb deep venous thrombosis (DVT) among neurorehabilitation admissions.DesignA prospective observational single-center study.SettingTertiary rehabilitation center affiliated to a public hospital.ParticipantsA total of 419 Asian neurorehabilitation admissions with a mean of 26 days to rehabilitation.InterventionAdmission screening protocol included quantitative D-dimer assay within 24 to 48 hours of rehabilitation admission and targeted hemiplegic/weaker lower-extremity venous duplex ultrasonography was performed if D-dimer assay level was elevated at 0.34 μg/mL or higher.Main Outcome MeasuresThere were 251 (59.9%) men, and the subjects were predominantly Chinese (76.6%). Subjects had a mean age of 59±15 years. Admitting diagnoses included ischemic stroke (212), hemorrhagic stroke and subarachnoid hemorrhage (129), traumatic brain injury (59), and nontraumatic brain injury (19). The screening protocol included a quantitative D-dimer assay within 24 to 48 hours of rehabilitation admission, and hemiplegic/weaker lower-extremity venous duplex ultrasonography was performed if D-dimer assay level was elevated at 0.34 μg/mL or higher.ResultsAltogether, 247 (58.9%) patients had an elevated D-dimer assay, and all underwent venous duplex ultrasonography. The incidence of lower-limb DVT was 5.01% (21), including 11 proximal and 10 distal DVT. No patients had clinical pulmonary embolism. Using 247 venous duplex ultrasonography results for analyses of correlates with logistic regression analyses, no significant demographic or clinical predictive factors for DVT were found.ConclusionsThis study confirms that asymptomatic lower limb DVT is indeed uncommon in Asian neurorehabilitation admissions. Possible reasons include genetic or ethnic protective factors, early walking initiated at rehabilitation, and timing of the admission protocol (median of 14 days postevent) when the maximal thrombotic risk was on the decline.