Timing of Hospital-Acquired Venous Thromboembolism (VTE) and its Relationship With VTE Prevention Measures in Immobile Patients

Abstract

This study describes the timing of venous thromboembolism (VTE) diagnosis in patients with cerebral or spinal trauma and stroke and the relationships between VTE prevention and timing of VTE diagnosis at a community hospital. This was a retrospective cohort observational study over a span of 10 years. Routine ultrasound surveillance identified 138 patients (61% men; mean age, 62 years) who developed VTE during their hospital stay. Mechanical prophylaxis was used in 79.7%, and pharmacologic prophylaxis in 78.3% of patients. The average time of admission to administration of mechanical prophylaxis was 1.92 days, and was 7.7 days for pharmacologic prophylaxis. In patients who received chemical prophylaxis within 2 days, 51.5% of all VTE events occurred during the first week, 73.5% during the first 2 weeks, and 91.2% during the first 3 weeks of the hospital stay. In patients who started chemical prophylaxis after the second day in the hospital, 85% of all VTE events occurred within the first week and 90% within the first 10 days of their hospital stay. The difference was statistically significant (P < .01). The timing of initiation of mechanical prophylaxis did not influence the timing of VTE events. In addition, the placement of inferior vena cava filters (IVCF) did not influence the incidence of pulmonary embolism in patients who received pharmacologic prophylaxis (18% with IVCF; 17% without IVCF). This study suggests that VTE screening in patients with cerebral or spinal trauma and stroke may be performed at a different schedule based on the timing of initiation of pharmacologic prophylaxis. In patients who did not start prophylaxis during the first 2 days, most VTEs can be diagnosed during the first 10 days. It appears that use of IVCF in patients who received pharmacological prophylaxis does not decrease the incidence of pulmonary embolism.