Strebel Niklaus, Prins Martin, Agnelli Giancarlo, Büller Harry R
Department of Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands.
Arch Intern Med. 2002 Jul 8;162(13):1451-6. doi: 10.1001/archinte.162.13.1451.
Prophylaxis of venous thromboembolism with low-molecular-weight heparins in patients undergoing major orthopedic surgery is currently initiated according to at least 3 different regimens. In Europe, traditionally, prophylaxis is started 12 hours before surgery, whereas in North America it is initiated 12 to 48 hours postoperatively. The third regimen (perioperative) begins prophylaxis either earlier than 12 hours before or 12 hours after surgery. Unfortunately, the optimal regimen is uncertain because direct comparisons among these regimens with sufficiently large sample sizes are not available.
To assess, in a systematic review, the relative efficacy and safety of the 3 low-molecular-weight heparin regimens used to prevent thrombosis after total hip replacement. The incidence of postoperative thrombosis detected by contrast venography was used as the measure of efficacy and the rate of major bleeding was used as the measure of safety.
We pooled the results of all published studies, which met the following criteria: (1) inclusion of in at least 1 arm of the study of a dose of low-molecular-weight heparin that is approved for both preoperative and postoperative initiation of prophylaxis; (2) the use of mandatory bilateral contrast venography, performed between days 6 and 15 postoperatively; (3) thromboprophylaxis continued until venography; (4) independent reading of venograms; and (5) assessment of clinically overt major bleeding by predefined criteria. Articles were excluded if no separate data could be obtained for patients undergoing elective hip surgery (in case of patient mix), or if they were reported more than once.
In the 1926 patients who used a preoperative regimen, the incidence of postoperative deep vein thrombosis was 19.2% (95% confidence interval [CI], 17%-21%). In the cohort of 925 patients who received a perioperative regimen, the rate of deep vein thrombosis was 12.4% (95% CI, 10%-14%), whereas in the group of 694 patients who received a postoperative regimen, it was 14.4% (95% CI, 12%-17%). The rate of major bleeding was 1.4% (95% CI, 1%-2%) in the preoperative group, 6.3% (95% CI, 5%-7%) in the perioperative group, and 2.5% (95% CI, 1%-3%) in the postoperative group.
We find no convincing evidence that starting prophylaxis preoperatively is associated with a lower incidence of venous thromboembolism than starting postoperatively. Perioperative regimens may lower the risk of postoperative thrombosis, but if so, this positive effect is offset by an increase in postoperative major bleeding.
目前，接受大型骨科手术的患者使用低分子量肝素预防静脉血栓栓塞至少有3种不同的方案。在欧洲，传统上预防措施在手术前12小时开始，而在北美则在术后12至48小时开始。第三种方案（围手术期）在手术前12小时之前或手术后12小时开始预防。不幸的是，由于无法获得足够大样本量的这些方案之间的直接比较，最佳方案尚不确定。
通过系统评价评估用于预防全髋关节置换术后血栓形成的3种低分子量肝素方案的相对疗效和安全性。将通过静脉造影检测到的术后血栓形成发生率用作疗效指标，将大出血发生率用作安全性指标。
我们汇总了所有符合以下标准的已发表研究结果：（1）研究的至少一个组中使用了一种既被批准用于术前也被批准用于术后预防的低分子量肝素剂量；（2）在术后第6至15天进行强制性双侧静脉造影；（3）血栓预防持续到静脉造影检查；（4）静脉造影照片独立判读；（5）根据预定义标准评估临床明显的大出血情况。如果无法获得择期髋关节手术患者的单独数据（如果是混合患者情况），或者文章被重复报道，则将其排除。
在1926例采用术前方案的患者中，术后深静脉血栓形成的发生率为19.2%（95%置信区间[CI]，17%-21%）。在925例接受围手术期方案的患者队列中，深静脉血栓形成率为12.4%（95%CI，10%-14%），而在694例接受术后方案的患者组中，该率为14.4%（95%CI，12%-17%）。术前组的大出血发生率为1.4%（95%CI，1%-2%），围手术期组为6.3%（95%CI，5%-7%），术后组为2.5%（95%CI，1%-3%）。
我们没有找到令人信服的证据表明术前开始预防与术后开始预防相比，静脉血栓栓塞的发生率更低。围手术期方案可能会降低术后血栓形成的风险，但即便如此，这种积极效果会被术后大出血的增加所抵消。
