Antiplatelet agents for preventing thrombosis after peripheral arterial bypass surgery.
BACKGROUND
Peripheral arterial disease (PAD) may cause occlusions (blockages) in the main arteries of lower limbs. One treatment option is bypass surgery using autologous (the patient's own tissue) vein graft or artificial graft. A number of factors influence occlusion rates, including the material used. To prevent graft occlusion patients are usually treated with antiplatelet, antithrombotic drugs, or a combination of both.


OBJECTIVE
To evaluate whether antiplatelet treatment in patients with symptomatic PAD undergoing infrainguinal bypass surgery improves graft patency, limb salvage and survival.


METHODS
The authors searched the Cochrane Peripheral Vascular Diseases Group Specialised Register (January 2008) and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 4). Additional trials were sought through reference lists of papers and proceedings from the vascular surgical society meetings.


METHODS
For this update the methodological quality of each original trial was assessed independently by review authors (JB, HM, AW) with emphasis on concealment of allocation.


METHODS
Details of the selected studies were extracted independently by JB and HM for the update. The treatment and control groups were compared for important prognostic factors and differences described. If any data were unavailable, further information was sought from authors. Data were synthesised by comparing group results. Unit of analysis issues were addressed by subgroup analysis.


RESULTS
The administration of a variety of platelet inhibitors resulted in improved venous and artificial graft patency when compared to no treatment. However, analysing patients for graft-type indicated that those patients receiving a prosthetic graft were more likely to benefit from administration of platelet inhibitors than patients treated with venous grafts.


CONCLUSIONS
Antiplatelet therapy with aspirin had a slight beneficial effect on the patency of peripheral bypass grafts but seemed to have an inferior effect on venous graft patency compared with artificial grafts. The effect of aspirin on cardiovascular outcomes and survival was small and not statistically significant. This might be due to the fact that the majority of patients receiving a peripheral graft have an advanced stage of PAD with critical ischaemia. They are usually seriously ill as a result of cardiovascular disease and have high mortality rates, of 20% per year. Additionally, the number of patients included in this analysis might be too small to reach a statistically significant effect for mortality and cardiovascular morbidity.
Brown
Julie
J
Obstetrics and Gynaecology , University of Auckland, FMHS, Auckland, New Zealand. j.brown@auckland.ac.nz
Lethaby
Anne
A
Maxwell
Heather
H
Wawrzyniak
Andrew J
AJ
Prins
Martin H
MH
D000714:Anastomosis, Surgical / Q000009:adverse effects / Q000379:methods; D001161:Arteriosclerosis / Q000601:surgery; D006083:Graft Occlusion, Vascular / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D007383:Intermittent Claudication / Q000601:surgery; D016491:Peripheral Vascular Diseases / Q000601:surgery*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D013927:Thrombosis / Q000517:prevention & control*; D014654:Vascular Patency
D010975:Platelet Aggregation Inhibitors