What clinical factors predict the incidence of deep venous thrombosis and pulmonary embolism in neurosurgical patients?

Object. Venous thromboembolisms (VTEs) occur frequently in surgical patients and can manifest as pulmonary emboli (PEs) or deep venous thromboses (DVTs). While many medical therapies have been shown to prevent VTEs, neurosurgeons are concerned about the use of anticoagulants in the postoperative setting. To better understand the prevalence of and the patient-level risk factors for VTE, the authors analyzed data from the National Surgical Quality Improvement Program (NSQIP).

Methods. Retrospective data on 1,777,035 patients for the years from 2006 to 2011 were acquired from the American College of Surgeons NSQIP database. Neurosurgical cases were extracted by querying the data for which the surgical specialty was listed as "neurological surgery." Univariate statistics were calculated using the chi-square test, with 95% confidence intervals used for the resultant risk ratios. Multivariate models were constructed using binary logistic regression with a maximum number of 20 iterations.

Results. Venous thromboembolisms were found in 1.7% of neurosurgical patients, with DVTs roughly twice as common as PEs (1.3% vs 0.6%, respectively). Significant independent predictors included ventilator dependence, immobility (that is, quadriparesis, hemiparesis, or paraparesis), chronic steroid use, and sepsis. The risk of VTE was significantly higher in patients who had undergone cranial procedures (3.4%) than in those who had undergone spinal procedures (1.1%).

Conclusions. Venous thromboembolism is a common complication in neurosurgical patients, and the frequency has not changed appreciably over the past several years. Many factors were identified as independently predictive of VTEs in this population: ventilator dependence, immobility, and malignancy. Less anticipated predictors included chronic steroid use and sepsis. Venous thromboembolisms appear significantly more likely to occur in patients undergoing cranial procedures than in those undergoing spinal procedures. A better appreciation of the prevalence of and the risk factors for VTEs in neurosurgical patients will allow targeting of interventions and a better understanding of which patients are most at risk.