Low-Dose versus Therapeutic Range Intravenous Unfractionated Heparin Prophylaxis in the Treatment of Patients with Severe Aneurysmal Subarachnoid Hemorrhage After Aneurysm Occlusion.

BACKGROUND: While prophylaxis with intravenous unfractionated heparin (UFH) can effectively prevent venous thromboembolism (VTE) during the neurocritical care of patients with severe aneurysmal subarachnoid hemorrhage (aSAH), the risk for intracranial bleeding complications might increase. Owing to this therapeutic dilemma, the UFH administration regimen in this critical patient population remains highly controversial.

METHODS: We performed a retrospective analysis of patients with severe aSAH (Fisher grade 3-4) receiving either low-dose (activated partial thromboplastin time [aPTT] <40 seconds) or therapeutic range (aPTT 50-60 seconds) UFH during intensive care unit (ICU) treatment after complete surgical/endovascular aneurysm occlusion. The primary outcome was the rate of bleeding/VTE complications and the investigation of potential risk factors.

RESULTS: This study series comprised 410 patients with aneurysmal SAH (aSAH), with a mean age of 54.7 ± 12.6 years, a male:female ratio of 1:2.2, and aSAH-associated intracerebral hemorrhage (ICH) in 33.2%. After complete aneurysm occlusion, 112 patients (27.3%) received therapeutic dose UFH and 298 patients (72.7%) received low-dose UFH. VTE events occurred in 5.4% of the low-dose UFH cohort and in 6.3% of the therapeutic dose UFH cohort, with no significant differences in the rate and severity of VTE events. However, an increase in initial SAH-associated ICH was significantly (P = 0.007) more frequent in the therapeutic dose cohort (18.8% vs. 3.4%). Heparin-induced thrombocytopenia (HIT) was the sole risk factor for VTE (P < 0.001), and both an aPTT ≥50 seconds under UFH administration (P = 0.007) and the initial presence of SAH-associated ICH (P = 0.035) were significant risk factors for intracranial bleeding complications.

CONCLUSIONS: Even in high-risk neurocritical patients with severe SAH and prolonged ICU treatment, low-dose UFH-administration for VTE prophylaxis is equally effective as therapeutic UFH administration and carries a lower risk of bleeding complications.