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We established an acute animal model for early, straightforward, and reproducible assessment of a biocompatible material interface. Bilateral femoral artery-to-vein shunts were created in 12 pigs: two tubes per shunt, the left two coated and the right two uncoated. We evaluated two groups: uncontrolled flow (UF; shunt flow unregulated) and controlled flow (CF; shunt flow ∼50 mL/min). For each case on each side, two shunts were evaluated: one for 1 h and the other for 3 h. Arterial blood gas and complete blood count were recorded at baseline, 1, and 3 h. Mean shunt flows were 532 ± 88 mL/min UF and 52 ± 8 mL/min CF. Differences in flow were much smaller in CF (0.5 mL/min; 1% of mean flow) than UF (24.8 mL/min; 5% of mean flow). In UF, significant changes occurred: in pH, from start of shunting through 1 h; in pO2 and pCO2, from start through 3 h. This swine model using bilateral femoral shunts with controlled blood flow provides a reliable, reproducible, easily implemented method by which to evaluate biocompatibility of device coatings at an early stage of investigation.

The purpose of this study was to evaluate in vivo the biocompatibility of BioMedFlex (BMF), a new resilient, hard-carbon, thin-film coating, as a blood journal bearing material in Cleveland Heart's (Charlotte, NC, USA) continuous-flow right and left ventricular assist devices (RVADs and LVADs). BMF was applied to RVAD rotating assemblies or both rotating and stator assemblies in three chronic bovine studies. In one case, an LVAD with a BMF-coated stator was also implanted. Cases 1 and 3 were electively terminated at 18 and 29 days, respectively, with average measured pump flows of 4.9 L/min (RVAD) in Case 1 and 5.7 L/min (RVAD) plus 5.7 L/min (LVAD) in Case 3. Case 2 was terminated prematurely after 9 days because of sepsis. The sepsis, combined with running the pump at minimum speed (2000 rpm), presented a worst-case biocompatibility challenge. Postexplant evaluation of the blood-contacting journal bearing surfaces showed no biologic deposition in any of the four pumps. Thrombus inside the RVAD inlet cannula in Case 3 is believed to be the origin of a nonadherent thrombus wrapped around one of the primary impeller blades. In conclusion, we demonstrated that BMF coatings can provide good biocompatibility in the journal bearing for ventricular assist devices.

Objective The purpose of this study was to evaluate the implantability of a novel epicardial mitral annuloplasty device and its ability to reduce the septal-lateral (S-L) dimension of the mitral annulus. Methods The devices were implanted on the beating heart in 2 healthy dogs (the 24-mm long device in dog A and the 27-mm and 24-mm standard devices in dog B) by sliding the anterior arm onto the floor of the transverse sinus and positioning the posterior arm just apical to the atrioventricular groove on the left ventricular posterolateral wall. The devices were secured with titanium helical tacks driven through the device into the ventricular wall. Two-dimensional epicardial echocardiograms were performed before and after device implantation to evaluate the degree of mitral regurgitation (MR) and the S-L dimension. Results Device implantation was uneventful, taking only ~30 seconds to deploy. MR (1 +) in both dogs at baseline was reduced to zero after implant. The reductions in S-L dimension in systole for the 24-mm device were 7.5% in dog A and 30.5% in dog B. For the 27-mm device in dog B, S-L reduction in systole was 29.9%. The leaflet coaptation length was increased in both cases. Conclusions The new device was effective in reducing S-L dimension and 1 + MR without requiring the use of cardiopulmonary bypass. We are currently evaluating this device for the treatment of MR in a rapid-pacing canine heart failure model.