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Stimulated prostacyclin release by conduits used for coronary artery bypass grafting
J Bonatti1, W Dichtl, E A Dworzak
1Division of Cardiac Surgery, University Clinic of Surgery, Innsbruck, Austria.
Insights
The internal mammary artery releases significantly more prostacyclin, a mediator that inhibits platelets and dilates blood vessels, compared to the right gastroepiploic artery and saphenous vein. This suggests the internal mammary artery may offer better protection against graft disease.
Area of Science:
- Cardiovascular Surgery
- Vascular Biology
- Biochemistry
Background:
- Coronary artery bypass grafting (CABG) relies on various conduits.
- The function of these conduits, particularly their release of prostacyclin, is crucial for graft patency.
- Prostacyclin is a key mediator for vasodilation and platelet inhibition.
Purpose of the Study:
- To directly compare prostacyclin release from three common CABG conduits: internal mammary artery (IMA), right gastroepiploic artery (RGEA), and saphenous vein (SV).
- To evaluate the impact of arachidonic acid (AA) stimulation on prostacyclin production in these conduits.
- To determine which conduit offers superior protection against thrombotic events and graft disease.
Main Methods:
- Vascular tissue samples (IMA, RGEA, SV) were obtained from patients undergoing CABG.
- Samples were incubated in HEPES medium, followed by stimulation with arachidonic acid (AA).
- Time-dependent production of 6-keto-prostaglandin F1 alpha, a stable prostacyclin metabolite, was measured.
Main Results:
- Under basal conditions, IMA and RGEA released more prostacyclin than SV.
- Following AA stimulation, IMA exhibited significantly higher prostacyclin metabolite release (806.0 ng/cm²) compared to RGEA (35.9 ng/cm²) and SV (82.3 ng/cm²).
- Statistical analysis (ANOVA) confirmed significant differences in prostacyclin release both within and between graft types (p < 0.0001).
Conclusions:
- The internal mammary artery demonstrates superior prostacyclin release compared to RGEA and SV after AA stimulation.
- Enhanced prostacyclin production by IMA may confer better protection against thrombotic events.
- IMA's inherent properties, mediated by prostacyclin, likely contribute to reduced development of coronary artery graft disease.
Abstract:
A direct comparison of the three coronary artery bypass conduits internal mammary artery (IMA), right gastroepiploic artery (RGEA), and saphenous vein (SV) concerning arachidonic acid (AA) stimulated release of the vasodilating and platelet inhibiting mediator prostacyclin was the aim of the present study. Pieces of saphenous vein (n = 16), right gastroepiploic artery (n = 8), and internal mammary artery (n = 19) were obtained from patients undergoing coronary artery bypass grafting. After a resting phase of 30 min in HEPES medium arachidonic acid (AA) was added in order to stimulate prostacyclin release. Time-dependent production of the stable prostacyclin metabolite 6-keto-prostaglandin F1 alpha was determined following stimulation. Under basal conditions the IMA (12.4 ng/cm2) and RGEA (12.0 ng/cm2) released more prostacyclin than saphenous vein (4.0 ng/cm2). After AA stimulation 6-keto-prostaglandin F1 alpha release at 30 min was as follows: IMA 806.0 ng/cm2, RGEA 35.9 ng/cm2, SV 82.3 ng/cm2 (p < 0.0001 within grafts, p < 0.0001 between grafts, ANOVA for repeated measures). The internal mammary artery in comparison with the right gastroepiploic artery and saphenous vein seems to be better protected against local thrombotic events and development of coronary artery graft disease with the aid of the vasodilating and platelet inhibiting mediator prostacyclin.