Animal model to compare the effects of suture technique on cross-sectional compliance on end-to-side anastomoses

Objective: An animal model has been developed to compare the effects of suture technique on the luminal dimensions and compliance of end-to-side vascular anastomoses. Methods: Carotid and internal mammalian arteries (IMAs) were exposed in three pigs (90 kg). IMAs were sectioned distally to perform end-to-side anastomoses on carotid arteries. One anastomosis was performed with 7/0 polypropylene running suture. The other was performed with the automated suture delivery device (Perclose/Abbott Labs Inc.) that makes a 7/0 polypropylene interrupted suture. Four piezoelectric crystals were sutured on toe, heel and both lateral sides of each anastomosis to measure anastomotic axes. Anastomotic cross-sectional area (CSAA) was calculated with: CSAA = pi x mM/4 where m and M are the minor and major axes of the elliptical anastomosis. Cross-sectional anastomotic compliance (CSAC) was calculated as CSAC = Delta CSAA/DeltaP where DeltaP is the mean pulse pressure and Delta CSAA is the mean CSAA during cardiac cycle. Results. We collected a total of 1 200 000 pressure-length data pel animal. For running suture we had a mean systolic CSAA of 26.94 +/- 0.4 mm(2) and a mean CSAA in diastole of 26.30 +/- 0.5 mm(2) (mean Delta CSAA was 0.64 mm(2)). CSAC for running suture was 4.5 x 10(-6)m(2)/kPa. For interrupted suture we had a mean CSAA in systole of 21.98 +/- 0.2 mm(2) and a mean CSAA in diastole of 17.38 +/- 0.3 mm(2) (mean Delta CSAA was 4.6 +/- 0.1 mm(2)). CSAC for interrupted suture was 11x10(-6)m(2)/kPa. Conclusions: This model, even with some limitations, can be a reliable source of information improving the outcome of vascular anastomoses. The study demonstrates that suture technique has a substantial effect on cross-sectional anastomotic compliance of end-to-side anastomoses. Interrupted suture may maximise the anastomotic lumen and provides a considerably higher CSAC than continuous suture, that reduces flow turbulence, shear stress and intimal hyperplasia. The Heartflo(TM) anastomosis device is a reliable instrument that facilitates performance of interrupted suture anastomoses. (C) 2001 Elsevier Science B.V. All rights reserved.