Coronary aspirate TNFα reflects saphenous vein bypass graft restenosis risk in diabetic patients

Background: Patients with diabetes mellitus (DM) have an increased risk for periprocedural complications and adverse cardiac events after percutaneous coronary intervention. We addressed the potential for coronary microvascular obstruction and restenosis in patients with and without DM undergoing stenting for saphenous vein bypass graft (SVG) stenosis under protection with a distal occlusion/aspiration device. Methods: SVG plaque volume and composition were analyzed using intravascular ultrasound before stent implantation. Percent diameter stenosis was determined from quantitative coronary angiography before, immediately after and 6 months after stent implantation. Coronary aspirate was retrieved during stent implantation and divided into particulate debris and plasma. Total calcium, several vasoconstrictors, and tumor necrosis factor (TNF)alpha in particulate debris and coronary aspirate plasma were determined. Results: Patients with and without DM had similar plaque volume, but larger necrotic core and greater particulate debris release in patients with than without DM (20.3 +/- 2.7 vs. 12.7 +/- 2.6% and 143.9 +/- 19.3 vs. 75.1 +/- 10.4 mg, P<0.05). The TNF alpha concentration in particulate debris and coronary aspirate plasma was higher in patients with than without DM (15.9 +/- 6.6 vs. 5.1 +/- 2.4 pmol/mg and 2.2 +/- 0.7 vs. 1.1 +/- 0.2 pmol/L, P<0.05), whereas total calcium and vasoconstrictors were not different. Patients with DM had a greater percent diameter stenosis 6 months after stent implantation than those without DM (22.17 +/- 5.22 vs. 6.34 +/- 1.11%, P<0.05). The increase in TNF alpha immediately after stent implantation correlated with restenosis 6 months later (r=0.69, P<0.05). Conclusion: In diabetics, particulate debris and coronary aspirate plasma contained more TNF alpha, which might reflect the activity of the underlying atherosclerotic process.