D-dimer screening for deep venous thrombosis in traumatic cervical spinal injuries

Background contextDeep venous thrombosis (DVT) in spinal cord injury (SCI) patients is a life-threatening comorbidity. Despite its seriousness, prophylaxis and screening for DVT in SCI patients are still not sophisticated.PurposeThis study aimed to define the epidemiology and incidence of DVT in acute traumatic cervical SCI in a Japanese population, determine the best timing for DVT screening, and determine the optimal D-dimer threshold level for use as an easy and minimally invasive screening tool.Study designThis is a prospective clinical study.Patient sampleThe patient sample included acute traumatic cervical SCI patients who were admitted to our facility within 2 weeks after injury.Outcome measureMultivariate logistic regression was performed for outcome measure.MethodsWe enrolled 268 patients (223 men and 45 women), from April 2007 to December 2012. After excluding early drop-out patients, 211 patients remained. Assessment for neurological status and blood chemistry, especially blood coagulation levels (prothrombin time, prothrombin time-international normalized ratio, activated partial thromboplastin time, and serum D-dimer), was performed every week until 1 month after injury. Ultrasonography was performed for DVT detection every 2 weeks.ResultsDeep venous thromboses were detected in 22 patients (10.4% of patients studied). All DVT-positive patients demonstrated severe paralysis classified as C or greater on the American Spinal Injury Association (ASIA) Impairment Scale. Multivariate logistic regression of clinical and laboratory parameters revealed that only the D-dimer level at 2 weeks after injury was an accurate predictor of DVT formation. The optimal threshold of D-dimer for prediction was determined to be 16 μg/dL. The sensitivity and specificity for detecting DVT were 77.3% and 69.2%, respectively.ConclusionsD-dimer levels may be used to predict the likelihood of DVT development in patients with acute cervical SCI. Furthermore, the optimal timing for screening test by D-dimer is 2 weeks after injury, and optimal threshold level for D-dimer for diagnosing DVT is 16 μg/dL. Such a screening test would be cost-efficient and simple to administer and could then be followed with additional investigations, such as ultrasonography or venography.