Comparative Endothelial Effects Of The Arterial Balloon Catheter On Elastic Versus Muscular Arterial Conduits

Background: Harvesting of arterial grafts such as the elastic internal mammary artery (IMA) or the muscular radial artery ( RA) for use in myocardial revascularization may result in severe spasm which can impair early graft flow. A new long intravascular balloon (ABC: Arterial Balloon Catheter, Applied Medical, CA, USA) has been developed to relieve arterial spasms without exerting any longitudinal shearing stress that could be damaging to the endothelial layer. The purpose of this study was to determine the effects of ABC balloon dilatation and reperfusion on the endothelial function of muscular and fibroelastic arteries.Methods: Two groups of swine were studied: group 1 had dilatation of both internal mammary arteries with a 3.5-mm via a medial sternotomy approach and group 2 had dilatation of both femoral arteries with a 3.5-mm ABC balloon. Left femoral and internal mammary arteries were reperfused during 45 minutes before harvesting. Non-instrumented segments of femoral and mammary arteries served as control. Endothelium-dependent relaxations to serotonin (5-HT: an agonist that binds to 5-HT1 receptors coupled to G(i) protein), bradykinin (BK: an agonist that binds to receptors coupled to G(q) protein) and the calcium ionophore A23187 (endothelium-dependent receptor independent agonist) were studied in standard organ chambers experiments.Results: In IMAs, there was a significant decrease in endothelium-dependent relaxations to 5-HT (p < 0.05) but not to BK and A23187 after dilatation with the 3.5-mm ABC balloon, with and without reperfusion, compared to controls. Reperfusion did not increase the endothelial dysfunction observed with 5-HT. In femoral arteries, there was a statistically significant decrease of endothelium-dependent relaxations to 5-HT, BK and A23187 after dilatation with the 3.5-mm ABC balloon in comparison with controls (p < 0.0005). Reperfusion further decreases endothelium-dependent relaxations to all agonists observed after balloon dilatation (p < 0.005).Conclusions: Arterial balloon catheter dilatation of muscular arteries using the 3.5-mm balloon causes a generalized endothelial dysfunction increased by reperfusion. The 3.5-mm arterial balloon dilatation causes a selective endothelial dysfunction in the swine internal mammary artery not aggravated by reperfusion. This suggests that the 3.5-mm arterial balloon catheter may be used safely for the fibroelastic IMA but may not be adequate for dilating the muscular RA. Undersizing of the ABC balloon may be crucial for these arteries.