Background: 

Stent implantation into atherosclerotic plaques releases, apart from particulate debris, soluble vasoconstrictor, thrombogenic and inflammatory substances which contribute to impaired microvascular perfusion. So far, the vasoconstrictor potential of such soluble mediators has been characterized in a bioassay using isolated rat mesenteric arteries, but not coronary arteries.

Methods: 

Using a distal protection/aspiration device, coronary arterial blood was retrieved during stent implantation in 15 patients with severe saphenous vein aorto-coronary bypass stenoses. The vasoconstriction of rat coronary and mesenteric arteries (2 mm length, each) in response to human coronary aspirate plasma was quantified in a small vessel myograph as isometric force development (mN). The arteries were challenged with KCl (120 mM) to define maximum vasoconstriction. On light microscopic examination at 80 mmHg, the diameter was 250±28 mm for coronary and 186±16 mm for mesenteric arteries.

Results: 

The KCl-induced maximal vasoconstriction was comparable for coronary and mesenteric arteries (5.8±1.8 mN vs. 7.2±1.7 mN; NS). However, human coronary aspirate plasma induced a greater vasoconstriction in coronary arteries than in mesenteric arteries (5.7±1.3 mN vs. 4.8±0.9 mN; p<0.05; paired t-test).

Conclusion: 

Human coronary aspirate, released during stenting of saphenous vein aorto-coronary bypass stenoses, induces profound, almost maximal vasoconstriction in rat coronary arteries.