Correspondence
Antiplatelet Therapy and Patency of Saphenous-Vein Bypass Grafts in the Legs
N Engl J Med 1998; 338:1387-1388May 7, 1998
- Article
To the Editor:
Becquemin (Dec. 11 issue) 1 reports the results of a randomized, prospective study demonstrating the improved patency of infrainguinal-vein bypass grafts in patients treated with the antiplatelet agent ticlopidine as compared with placebo. The data appear to demonstrate an important effect and to confirm a widely held belief that properly administered antiplatelet therapy promotes the patency of vascular reconstructions.
Several factors, however, may limit widespread application of these findings. First, it should be noted that the patency rates in the placebo group were significantly inferior to those reported in single-institution studies at high-volume centers. In general, the current literature indicates secondary patency rates for infrainguinal-vein grafts of 80 percent at five years, which is similar to the trend of early results noted in the ticlopidine-treated group.2-4 The multi-institutional nature of the study by Becquemin and colleagues, with the associated potential for variations in surgical technique and postoperative surveillance or intervention, may be an important factor in the overall inferior results. For example, were there significant differences among the centers in the indications for or frequency of reinterventions to maintain graft patency?
These issues notwithstanding, the differences observed with treatment are quite striking. To understand better the potential effects of ticlopidine, some further analysis of the graft failures would be useful. The curves separate most dramatically at two to four months, a period when intimal hyperplasia is a prominent cause of failure. Were there any differences between the groups in the anatomy of lesions causing graft failure? Was the difference in patency of similar magnitude in patients with claudication and those with critical ischemia? Were the results better at the institutions performing a larger volume of procedures?
Most important, the utility of the study is greatly diminished by the absence of a comparison with the standard antiplatelet agent, aspirin. Although there are conflicting reports in the literature regarding the effects of aspirin on lower-extremity bypass, meta-analysis suggests that vascular-graft occlusions may be reduced by approximately one third in treated patients.5 We routinely prescribe aspirin both before and after surgery for patients with lower-extremity arterial disease, on the basis of the well-documented benefit of aspirin in preventing adverse cardiovascular events. Unless and until ticlopidine can be demonstrated to offer a clear advantage over aspirin in patients who require lower-extremity bypass, there appears to be no justification for incurring its higher cost and risk of side effects.
5 ReferencesMichael S. Conte, M.D.
Michael Belkin, M.D.
Magruder C. Donaldson, M.D.
Anthony D. Whittemore, M.D.
Brigham and Women's Hospital, Boston, MA 021151
Becquemin J-P . Effect of ticlopidine on the long-term patency of saphenous-vein bypass grafts in the legs. N Engl J Med 1997;337:1726-1731
Full Text | Web of Science | Medline2
Taylor LM Jr ,Edwards JM ,Porter JM . Present status of reversed vein bypass grafting: five-year results of a modern series. J Vasc Surg 1990;11:193-206
CrossRef | Web of Science | Medline3
Donaldson MC ,Mannick JA ,Whittemore AD . Femoral-distal bypass with in situ greater saphenous vein: long-term results using the Mills valvulotome. Ann Surg 1991;213:457-465
CrossRef | Web of Science | Medline4
Belkin M ,Conte MS ,Donaldson MC ,Mannick JA ,Whittemore AD . The impact of gender on the results of arterial bypass with in situ greater saphenous vein. Am J Surg 1995;170:97-102
CrossRef | Web of Science | Medline5
Antiplatelet Trialists' Collaboration
CrossRef | Web of Science
Author/Editor Response
Dr. Becquemin replies:
To the Editor: We agree that in the placebo group the patency rate was inferior to that reported in single-institution series. We found at least two reasons for this result. First, multicenter controlled studies always have poorer results than those of retrospective single-institution series. This was true in our study of femoropopliteal bypasses and in trials involving carotid surgery,1 as well as in studies of abdominal aortic-aneurysm repair.2 The reasons for these discrepancies are multiple, one being the effect of an independent committee evaluating the end points.
Second, in one series of femoropopliteal-vein grafts,3 patients were given aspirin, which, as stated by Conte et al., who cite the Antiplatelet Trialists' Collaboration study,4 may improve the patency rate. We were unable to find any statistically significant differences in patency according to any of the following factors: lesions causing graft failure, preoperative symptoms, indications for or frequency of reintervention, or volume of procedures per center.
The use of aspirin in the control group rather than placebo is obviously an important issue. In the Discussion section of our article, we gave the reasons for our choice. Nevertheless, since the efficacy of ticlopidine for this indication is now clearly established, there may be a need for subsequent studies with different antiplatelet agents. In the light of recent studies of the coronary circulation,5 we would suggest the evaluation of aspirin plus ticlopidine or aspirin plus clopidogrel. Clopidogrel has fewer side effects than ticlopidine.
5 ReferencesJean-Pierre Becquemin, M.D.
Centre Hospitalier Universitaire Henri Mondor, 94000 Créteil, France1
European Carotid Surgery Trialists' Collaborative Group
CrossRef | Web of Science | Medline2
Becquemin JP ,Chemla E ,Allaire E ,Desgranges P ,Melliere D . Anevrisme de l'aorte abdominale: résultats du traitement chirurgical moderne à froid. J Cardiovasc Surg (Torino) 1998;39:15-21
Web of Science | Medline3
Donaldson MC ,Mannick JA ,Whittemore AD . Femoral-distal bypass with in situ greater saphenous vein: long-term results using the Mills valvulotome. Ann Surg 1991;213:457-465
CrossRef | Web of Science | Medline4
Antiplatelet Trialists' Collaboration
CrossRef | Web of Science5
Leon MD ,Bain DS ,Gordon P , et al. Clinical and angiographic results from the Stent Anticoagulation Regimen Study (STARS). Circulation 1996;94:Suppl I:I-685 abstract.
