SAN ANTONIO – Initiation of venous thromboembolism prophylaxis within 72 hours of severe traumatic brain injury (TBI) reduced the odds of venous thromboembolism by 50% without increasing subsequent intracranial complications or death in a large, propensity-matched cohort study from the University of Toronto.
The investigators matched 1,234 adult patients given prophylaxis before 72 hours – the early-prophylaxis (EP) group – to 1,234 given prophylaxis at 72 hours or later – the late-prophylaxis (LP) group – based on demographics, injury characteristics, intracranial lesions, early neurosurgical procedures, and prophylaxis type.
EP patients had a significantly lower rate of pulmonary embolism (1.1% vs. 2.4%; odds ratio, 0.48; 95% confidence interval, 0.25-0.91) and deep vein thrombosis (4.2% vs. 7.9%; OR, 0.51; 95% CI, 0.36-0.72), with no significant increase in the risk of death (9.8% EP vs. 9% LP; OR, 1.1; 95% CI 0.84-1.4) or late secondary craniotomy/-ectomy (EP 2.5% vs. LP 2.9%; OR, 0.86; 95% CI 0.53-1.4) or intracranial monitoring/drainage (EP 1.1% vs. LP 1.4%; OR, 0.76; 95% CI 0.37-1.6) from VTE complications or other reasons.
“Practice guidelines say we should initiate VTE [venous thromboembolism] prophylaxis” in severe TBI “as early as possible. It’s a very loose recommendation,” so some centers wait 72 hours or longer for fear of extending intracranial hemorrhages. Pending results from prospective trials, “our study lends evidence that early prophylaxis in this population may be safe,” said investigator and University of Toronto general surgery resident, Dr. James Byrne.
The study included 3,634 severe, adult TBI patients in the American College of Surgeons Trauma Quality Improvement Program database from 2012-2014. The subjects had head Abbreviated Injury Scale (AIS) scores of at least 3, Glasgow Coma Scale scores of no more than 8, and, in almost all cases, initial surgeries within 48 hours. Injury was due to blunt trauma. Patients who died or were discharged within 5 days of their injury and those with severe injuries to other body areas were excluded from the analysis.
The median time to starting VTE prophylaxis was 84 hours across the 186 trauma centers in the study, but ranged from 48-150 hours. Centers started prophylaxis within 72 hours in 18%-54% of patients. Fifty-five percent of patients had prophylaxis with low-molecular-weight heparin, and the rest with unfractionated heparin. Overall, 1.7% of patients developed pulmonary emboli, and 6.5% deep vein thromboses. Less than 3% had secondary neurosurgical interventions.
Prophylaxis was more likely to be delayed past 72 hours in patients with higher head AIS scores; subdural hematomas; subarachnoid hemorrhages; blood transfusions within 12 hours of admission; and early neurosurgery. Low-molecular-weight heparin was the more likely option past 72 hours.
Among the 114 centers who treated 10 or more patients, there was a continuous trend toward lower VTE rates with higher EP use, a rate of 9.1% in centers using EP in 18% of patients, but 6.1% in centers using it in 54% (P = .126).
The decision of when to start prophylaxis in severe TBI “still needs to be made at the patient level, but it may be safe to start earlier than 72 hours,” Dr. Byrne said.
The median age in the study was about 43 years, and three-quarters of the subjects were men. Most of the injuries were due to falls or motor vehicle crashes.
Dr. Byrne had no disclosures.