Prolonged prophylaxis after joint replacement: another step sideways?

The Post-thrombotic Syndrome: The Forgotten Morbidity of Deep Venous Thrombosis

The postthrombotic syndrome (PTS) is the most common complication of deep venous thrombosis (DVT) yet has received little attention from clinicians and researchers. Clinically, PTS is characterized by chronic pain, swelling, heaviness and other signs in the affected limb. In severe cases, venous ulcers may develop. PTS is burdensome and costly to patients and society because of its high prevalence, severity and chronicity. Preventing DVT with the use of effective thromboprophylaxis in high-risk patients and settings and minimizing the risk of ipsilateral DVT recurrence are likely to reduce the frequency of PTS. Compression stockings worn daily after DVT appear to reduce the incidence and severity of PTS but questions regarding their use and effectiveness remain. Future research should focus on identifying patients at high risk for PTS, assessing the role of thrombolysis in preventing PTS and evaluating the optimal use of compression stockings in preventing and treating PTS. In addition, new therapies to treat PTS should be sought and evaluated.

The post-thrombotic syndrome: current knowledge, controversies, and directions for future research

The post-thrombotic syndrome (PTS) is a long-term complication of deep venous thrombosis (DVT) that is characterized by chronic, persistent pain, swelling and other signs in the affected limb. PTS is common, burdensome and costly. It is likely to increase in prevalence, since despite widespread use of and improvements in the efficacy of thromboprophylaxis, the incidence of DVT has not decreased over time. About 20-50% of patients develop PTS within 1-2 years of symptomatic DVT, and severe PTS, which can include venous ulcers, occurs in 5-10% of cases. Although there is no gold standard for the diagnosis of PTS, the presence of typical clinical features in a patient with previous DVT provides strong supporting evidence. Objective evidence of venous valvular incompetence helps to confirm the diagnosis in symptomatic patients. Preventing ipsilateral recurrence of DVT, by ensuring an adequate duration and intensity of anticoagulation for the initial DVT and by prescribing situational thromboprophylaxis after discontinuation of oral anticoagulants, is likely to reduce the risk of developing PTS. There is no proven role for thrombolysis of the initial DVT to prevent PTS. Daily use of graduated compression stockings after DVT may reduce the risk of PTS, and may prevent worsening of established PTS. Pending the results of ongoing studies, stockings are recommended in patients with persistent symptoms or swelling after DVT. Future research should focus on standardizing criteria for PTS diagnosis, identification of DVT patients at high risk for PTS, and rigorously evaluating the effectiveness of stockings, thrombolysis, and venoactive drugs in preventing or treating PTS.

Extended-duration prophylaxis against venous thromboembolism after total hip or knee replacement: a meta-analysis of the randomised trials

BACKGROUND

The optimum duration of prophylaxis against venous thromboembolism after total hip or knee replacement is uncertain. Our primary objective was to establish the efficacy of extended-duration prophylaxis on symptomatic venous thromboembolic events.

METHODS

We identified randomised trials comparing extended-duration prophylaxis using heparin or warfarin with placebo or untreated control in patients undergoing elective total hip or knee replacement by searching electronic databases (MEDLINE, EMBASE), references from retrieved articles, and abstracts from conference proceedings, and by contact with pharmaceutical companies and investigators. Two reviewers independently extracted data on study design, symptomatic and symptomless venographic venous thromboembolism, death, and bleeding outcomes. Results from individual trials were combined with the Mantel-Haenszel method.

FINDINGS

Nine studies met our inclusion criteria (3999 patients), eight with low molecular weight heparin, and one with unfractionated heparin. Extended-duration prophylaxis for 30-42 days significantly reduced the frequency of symptomatic venous thromboembolism (1.3% vs 3.3%, OR 0.38; 95% CI 0.24-0.61, numbers needed to treat [NNT]=50), with no statistical evidence of heterogeneity (x(2) test, p=0.69). There was a greater risk reduction in patients undergoing hip replacement (1.4% vs 4.3%, 0.33; 0.19-0.56, 34) compared with knee replacement (1.0% vs 1.4%, 0.74; 0.26-2.15, 250). A significant reduction in symptomless venographic deep vein thrombosis was also observed (9.6% vs 19.6%, 0.48; 0.36-0.63, 10). There was no increase in major bleeding but extended-duration prophylaxis was associated with excess minor bleeding (3.7% vs 2.5%, 1.56; 1.08-2.26, numbers needed to harm [NNH]=83).

INTERPRETATION

Among patients undergoing total hip or knee replacement, extended-duration prophylaxis significantly reduces the frequency of symptomatic venous thromboembolism. The reduction in risk is equivalent to about 20 symptomatic events per 1000 patients treated.