Influence of stent expansion states on platelet deposition in an extracorporeal porcine arteriovenous shunt model using a multichannel perfusion chamber

Limited data are available about incomplete stent expansion (SE) on platele t deposition (PD). We examined PD following different SE using an extracorp oreal porcine arteriovenous shunt model to which a perfusion chamber with f our parallel silastic tubes were connected. Blood flow was set at a 20 and 100 mL/min in 1.8 and 3.1 mm diameter tubes, respectively. P154 stents were deployed completely (Group A, n=15) or incompletely (Group B, n=15) in 1.8 mm (n=13) and 3.1 mm (n=17) tubes. Cr-51-labelled platelet autologous bloo d was injected 1 hr before the perfusion. After 15 min-perfusion, the testi ng tubes were assessed for radioactivity counts. In-stent cross sectional a rea was measured by intravascular ultrasound. There was a significant diffe rence in PD between group A and B regardless of channel size (118+/-18.4 vs 261.4+/-52.1 plts x 10(6)/cm(2), p<0.05). With adjusted shear rate and sim ilar stenosis, PD was similar in both tubes. In smaller 1.8 mm tubes, a ste nosis as subtle as 10% was associated with a significant PD difference (226 .1+/-20 vs 112.9+/-20.5 plts x 10(6)/cm(2), p<0.005). This model enabled a repetitive, simultaneous comparison of PD following different SE states. It seems that the quality of SE remains crucial in smaller channels.