Internal mammary artery and saphenous vein graft patency. Effects of aspirin
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S Goldman1, J Copeland, T Moritz
1Department of Veterans Affairs Medical Center, Tucson, AZ 85723.
Insights
Internal mammary artery and saphenous vein grafts show excellent 1-year patency after bypass surgery. Aspirin treatment did not significantly alter graft patency rates for either type of coronary artery bypass graft.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Pharmacology
Background:
- Coronary artery bypass grafting (CABG) is a common procedure to restore blood flow to the heart.
- Graft patency is crucial for long-term CABG success, with internal mammary artery (IMA) and saphenous vein grafts (SVG) being primary options.
- The role of aspirin in influencing graft patency post-CABG requires continued investigation.
Purpose of the Study:
- To compare the 1-year angiographic patency rates of internal mammary artery (IMA) versus saphenous vein grafts (SVG) to the left anterior descending (LAD) coronary artery.
- To evaluate the effect of aspirin, alone or in combination with dipyridamole, on IMA and SVG patency at 1 year post-CABG.
Main Methods:
- Angiographic data were collected at 1 year post-CABG in patients from two Department of Veterans Affairs Cooperative Trials.
- Patients received varying aspirin dosages (325 mg q.d., 325 mg t.i.d.), aspirin plus dipyridamole, or placebo.
- Aspirin administration timing (pre- or post-operation) and patient stratification by disease extent were employed.
Main Results:
- Overall IMA graft patency was 92.8% (220/237), and SVG patency was 90.1% (345/383) at 1 year (p = 0.309).
- No significant differences in IMA graft patency were observed between aspirin and placebo groups (92.1% vs. 100.0%, p = 0.385).
- No significant differences in SVG graft patency were observed between aspirin and placebo groups (90.4% vs. 88.8%, p = 0.675).
Conclusions:
- Both IMA and SVG grafts demonstrate excellent 1-year patency rates following coronary artery bypass surgery.
- Aspirin therapy, at the dosages and timings studied, did not significantly impact the patency of either IMA or SVG grafts at 1 year.
- There were no significant differences in 1-year patency between IMA and SVG grafts to the LAD coronary artery.
Abstract:
As part of two Department of Veterans Affairs Cooperative Trials, we obtained angiographic patency data for internal mammary artery (IMA) and saphenous vein grafts to the left anterior descending (LAD) coronary artery at 1 year after coronary artery bypass surgery. Patients received either aspirin 325 mg q.d., aspirin 325 mg t.i.d., aspirin 325 mg and dipyridamole 75 mg t.i.d., or placebo. Aspirin was initiated either 12 hours before or 6 hours after operation. Patients were stratified preoperatively for extent of disease and randomized to the therapies outlined above. There was no randomization to IMA versus saphenous vein grafts to the LAD. When the patients taking placebo were compared with those taking aspirin, there were no differences in the IMA (100.0% versus 92.1%, p = 0.385) or vein graft (88.8% versus 90.4%, p = 0.675) patency rates. The patency rate, irrespective of treatment, for all IMA grafts was 92.8% (220 of 237) versus 90.1% (345 of 383) for all vein grafts to the LAD (p = 0.309). Thus, both the IMA and vein grafts had excellent patency rates at 1 year. Aspirin did not alter this at 1 year, and there were no differences between IMA and vein graft patency to the LAD.