Use of unfractionated heparin to reduce venous thromboembolism in patients with aneurysmal subarachnoid hemorrhage: Results from a single-center retrospective cohort study.

Abstract

Introduction Patients with aneurysmal subarachnoid hemorrhage (a-SAH) are at high risk for venous thromboembolism (VTE). While risk factors for VTE in this patient population are well known, there is currently paucity of data regarding optimal chemical prophylaxis practices, and it is left to individual provider to decide on drug, dose and timing of initiation of chemical prophylaxis. Purpose of the study The University of Kansas Medical Center's dedicated neurocritical care unit implemented a VTE prophylaxis protocol (subcutaneous unfractionated heparin) in 2011. This study was undertaken to gain insight into practices surrounding the adoption of the protocol and rates of VTE events over 5 years as a quality improvement initiative. Materials and methods A retrospective cohort study was conducted on patients with confirmed SAH after cerebral aneurysm rupture admitted between July 1, 2008 and December 31, 2013 were included in this study. Exposure of interest was unfractionated heparin, and the outcome measures were venous thromboembolism events (VTEs), and adverse events due to UFH. Descriptive analysis was performed to study time to initiation of heparin, utilization of heparin and incidence of VTE. Result. There were 125 patients who met inclusion criteria and 95 (75.8%) received chemical prophylaxis. Implementation of VTE prophylaxis protocol led to an increase from 42.9% to 100% UFH initiation within five years. Time to initiation of UFH also dropped (168.3 hours to 92 hours, p-value 0.0148, 95% CI 18.644 -134). There were a total of 19 VTE events (15.32 % incidence) were identified in our study cohort but the rate of VTE declined over time. . Adverse events noted with use of UFH included; retroperitoneal hematoma (2 events), heparin induced thrombocytopenia (3 events), worsening of pre-existing hemorrhage (1 event), and hemorrhage along external ventricular track (1 event). None of the adverse events related to UFH were fatal. Conclusions Chemical prophylaxis can be safely used in patients with a-SAH, after securement of aneurysm, and establishment of clinical stability, and may reduce the risk of VTE. VTE events are possible despite the use of UFH.