Postoperative Thromboembolic Prophylaxis with Low-Molecular-Weight Heparin and Risk of Rebleeding in Patients with Chronic Subdural Hematomas: A Comparative Retrospective Cohort Study.

Abstract

Early postoperative administration of low-molecular-weight heparin (LMWH) to prevent thromboembolic events in patients with chronic subdural hematoma (CSDH) is controversial. Our goal was to investigate impact of early postoperative LMWH administration on recurrence rate of CSDHs. Retrospective review was performed of 136 patients with CSDHs who were operated on during an 18-month period. Early postoperative administration of LMWH was at the discretion of the treating surgeon. This resulted in patients treated (heparin [H] group) or not treated with LMWH (no heparin [NH] group). All patients underwent imaging 4 weeks after surgery or earlier in cases of deterioration. The primary outcome variable was reoperation. Secondary outcomes were reoperation, important residual hematoma (defined as hematoma depth of more than one third of original size), and incidence of thromboembolic complications. Relative risk and absolute risk reduction were calculated. We included 105 patients, 50 (47.6%) in the NH group and 55 (52.4%) in the H group. Nine patients (18%) in the NH group and 6 patients (10.9%) in the H group required secondary surgery (relative risk 0.61, 95% confidence interval 0.23-1.58, P= 0.404, absolute risk reduction 0.07). Eleven patients (22%) in the NH group and 15 patients (27.3%) in the H group presented with important residual hematoma or underwent surgery for hematoma recurrence (relative risk 1.24, 95% confidence interval 0.63-2.44, P=0.532, absolute risk reduction-0.05). Our data provide preliminary evidence that early postoperative administration of LWMH does not increase risk of clinically relevant recurrence of CSDHs.