TRANSIENT POSTOPERATIVE STENOSIS IN SMALL-VESSEL ANASTOMOSES

Using a newly developed Doppler probe, we have found that a standard s uture anastomosis in a rat femoral artery is accompanied by significan t (30-60%) cross-sectional area stenosis, which dissipates to baseline levels within 24 hours. We hypothesized that spasm, deposition of coa gulation products, or the suture technique itself was responsible. Top ical vasodilators (papaverine, sodium nitroprusside, lidocaine) and in travenous thromboxane A(2) synthetase inhibitor and receptor blocking agent (Ridogrel, 4 mg/ml), anticoagulants heparin and SC4992 (an exper imental platelet inhibitor/arginine-glycine-aspartic acid analogue), w ere administered. No drug had any significant effect on preventing pos toperative stenosis. Varied suture bites affected stenosis measurement s. Scanning electron microscopy and light microscopy displayed ''bunch ing'' of vessel wall in the suture ties. This was confirmed with methy l methacrylate corrosion casts and microangiography. ''Sham'' anastomo ses also produced stenosis, which was relieved when sutures were remov ed. We conclude that suture anastomosis of small vessels is accompanie d by significant cross-sectional stenosis caused by the physical actio n of tensioned sutures. This effect dissipates over a 24-hour postoper ative period. The mechanism behind these changes and the clinical impo rtance of this effect are still under investigation.