Thrombolysis for acute deep vein thrombosis.
BACKGROUND
Standard treatment for deep vein thrombosis aims to reduce immediate complications. Use of thrombolysis or clot dissolving drugs could reduce the long-term complications of post-thrombotic syndrome (PTS) (pain, swelling, skin discolouration, or venous ulceration) in the affected leg. This is the second update of a review first published in 2004.


OBJECTIVE
To assess the effects of thrombolytic therapy and anticoagulation versus anticoagulation in the management of people with acute deep vein thrombosis (DVT) of the lower limb as determined by the effects on pulmonary embolism, recurrent venous thromboembolism, major bleeding, post-thrombotic complications, venous patency and venous function.


METHODS
For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched April 2013) and CENTRAL (2013, Issue 4).


METHODS
Randomised controlled trials (RCTs) examining thrombolysis and anticoagulation versus anticoagulation for acute DVT were considered.


METHODS
In the previous review of 2010, one review author (LW) selected trials, extracted data and assessed study quality, with checking at all stages by the other review author (MPA). If necessary, we sought additional information from trialists. For this update (2013), LW and CB selected trials, extracted data independently, and sought advice from MPA where necessary. All studies, existing and new, required full risk of bias assessment in line with current Cochrane procedures. Two of LW, CB and MA independently assessed risk of bias with discussion with the third author where necessary.


RESULTS
Seventeen studies with 1103 participants were included. Complete clot lysis occurred significantly more often in the treatment group in early follow up (risk ratio (RR) 4.91; 95% confidence interval (CI) 1.66 to 14.53, P = 0.004) and at intermediate follow up (RR 2.37; 95% CI 1.48 to 3.80, P = 0.0004). A similar effect was seen for any degree of improvement in venous patency. Significantly less PTS occurred in those receiving thrombolysis, (RR 0.64; 95% CI 0.52 to 0.79, P < 0.0001). Leg ulceration was reduced although the data were limited by small numbers (RR 0.48; 95% CI 0.12 to 1.88, P = 0.29). Those receiving thrombolysis had significantly more bleeding complications (RR 2.23; 95% CI 1.41 to 3.52, P = 0.0006). Three strokes occurred in the treatment group, all in trials conducted pre-1990, and none in the control group. There was no significant effect on mortality detected at either early or intermediate follow up. Data on the occurrence of pulmonary embolism (PE) and recurrent DVT were inconclusive. Systemic thrombolysis is now not commonly used and catheter-directed thrombolysis (CDT) is the more favoured means of administration. This has been studied in iliofemoral DVT, and results from two trials are consistent with those from trials of systemic thrombolysis in DVT at other levels of occlusion.


CONCLUSIONS
Thrombolysis increases the patency of veins and reduces the incidence of PTS following proximal DVT by a third. Strict eligibility criteria are necessary to reduce the risk of bleeding complications and this limits the applicability of this treatment. In those who are treated there is a small increased risk of bleeding. In recent years CDT is the most studied route of administration, and results appear to be similar to systemic administration.
Cameron House, Cameron Bridge, Windygates, Leven, UK, KY8 5RG.
Lorna
L
Watson
Cathryn
C
Broderick
Matthew P
MP
Armon
D000925:Anticoagulants / Q000627:therapeutic use; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D015912:Thrombolytic Therapy / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome; D014647:Varicose Ulcer / Q000517:prevention & control; D020246:Venous Thrombosis / Q000150:complications / Q000188:drug therapy*
D000925:Anticoagulants