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Antithrombotic therapy in patients with saphenous vein and internal mammary artery bypass grafts
Insights
Aspirin effectively prevents saphenous vein bypass graft occlusion for one year when initiated around surgery. Extended aspirin use beyond one year offers no additional graft patency benefits.
Area of Science:
- Cardiovascular Surgery
- Pharmacology
Background:
- Saphenous vein graft (SVG) occlusion is a significant complication after coronary artery bypass grafting (CABG).
- Antiplatelet therapy is crucial for maintaining graft patency.
Purpose of the Study:
- To evaluate the efficacy and safety of aspirin, alone and in combination with dipyridamole, in preventing SVG occlusion.
- To determine the optimal timing and duration of aspirin therapy for SVG patency.
Main Methods:
- Systematic review and meta-analysis of studies investigating aspirin and dipyridamole for SVG occlusion prevention.
- Analysis of graft occlusion rates, bleeding complications, and long-term patency based on treatment regimens and timing.
Main Results:
- Aspirin (100-975 mg/d) is effective in reducing SVG occlusion for one year when started perioperatively.
- Combination therapy with aspirin and dipyridamole showed no added benefit over aspirin alone for graft occlusion.
- Increased bleeding risk was observed with aspirin initiated one day before surgery and with combination therapy.
Conclusions:
- Perioperative aspirin initiation is effective for short-term SVG patency.
- Extended aspirin use beyond one year does not improve long-term graft patency.
- Combination therapy with dipyridamole increases bleeding risk without enhancing SVG occlusion prevention compared to aspirin alone.
Abstract:
In most studies, aspirin has been shown to be effective for a period of 1 year in reducing the frequency of saphenous vein bypass graft occlusion when begun 1 day before surgery, on the day of surgery, or the day after surgery. Effective doses of aspirin range from 100 to 975 mg/d. Aspirin in combination with dipyridamole is effective in the prevention of saphenous vein bypass graft occlusion if aspirin and dipyridamole therapy is started 1 or 2 days before surgery or aspirin therapy is started on the day of surgery but dipyridamole therapy is started before surgery or if treatment with both aspirin and dipyridamole is started 1 day after surgery. Aspirin in combination with dipyridamole is not more effective than aspirin alone in the prevention of saphenous vein graft occlusion. Bleeding is higher among patients treated with aspirin alone than among controls if aspirin therapy is started 1 day before surgery. Bleeding is not greater in comparison to controls if aspirin therapy is started the day of surgery or 1 day after surgery. When aspirin and dipyridamole are used in combination, bleeding is higher than in controls, and bleeding is higher than with aspirin alone. The continued use of aspirin for 2 additional years after an initial year of aspirin therapy for the prevention of saphenous vein bypass graft occlusion showed no additional long-term benefit on graft patency at the end of the third year.