Intraoperative heparin thromboembolic prophylaxis in primary total hip arthroplasty. A prospective, randomized, controlled, clinical trial.
Academic Article
Overview
abstract
Venous thromboembolic disease remains the most common and potentially fatal complication after total hip arthroplasty (THA). Proximal femoral deep vein thrombosis (DVT) is especially prone to propagate and embolize. The authors' hypothesis was that intraoperative intravenous heparin administration could reduce proximal DVT in THA. There were 286 patients who entered into a prospective, double-blind, randomized clinical trial at the authors' institution between June 1988 and May 1990. All patients had unilateral primary THA under hypotensive epidural anesthesia. The epidural catheter was placed at least 60 minutes before heparin administration. Intravenous heparin was given during surgery only. All patients received aspirin twice daily (650 mg/day) after surgery. Detection of DVT was by contrast venography on Postoperative Day 6 or 7. The study was divided into three phases. There was four groups: control (intraoperative saline), 30 minutes (1000 U heparin at beginning of surgery followed by 500 U every 30 minutes), continuous adjusted (1000 U or 1500 U initial bolus followed by continuous heparin infusion maintaining anticoagulation at 30%-50% elevation from baseline), and fixed dose (1000 U bolus before hip dislocation, and 500 U bolus before femoral canal preparation). Proximal femoral DVT was effectively reduced from 9.1% in the control group to 1.7% in the heparin groups (1.7% in 30 minute, 1.6% in continuous adjusted, 1.7% in fixed dose) (p less than 0.02). The overall DVT rate was also significantly reduced from 24.3% to 10% (p less than 0.01). No adverse effects from heparin administration were noted. Postoperative drainage, hematocrit levels on Postoperative Day 2 and at discharge, and transfusion requirements were not significantly different among the groups. The current recommended protocol is 1000 U bolus five minutes before hip dislocation, followed by 500 U bolus five minutes before femoral preparation. This, in conjunction with hypotensive epidural anesthesia and postoperative aspirin, is effective in reducing proximal DVT to less than 2% in primary THA.
