Chlorhexidine-coated peripherally inserted central catheters reduce fibroblastic sleeve formation in an in vivo ovine model.

PURPOSE:: This study compared an antimicrobial and anti-thrombogenic peripherally inserted central catheter treated with a chlorhexidine-based technology, a peripherally inserted central catheter with bulk distributed fluoro-oligomers, and a poly 2-methoxyethyl acrylate-based peripherally inserted central catheter to an untreated peripherally inserted central catheter (control) in an ovine model at 14 and 30 days post-implant. METHODS:: One of four types of peripherally inserted central catheters was surgically implanted into the left jugular vein of each of 18 sheep for 14 or 30 days. Blood analysis consisted of complete blood counts, serum chemistries, and coagulation (fibrinogen, prothrombin time, and partial thromboplastin time) profiles. Sheep were sacrificed to examine the vein and thorax. Histological analysis was performed on serial catheter sections using standard microscopy on hematoxylin and eosin-stained tissues. RESULTS:: All catheters developed fibroblastic sleeves at both 14 and 30 days. The chlorhexidine-peripherally inserted central catheter showed a 64% lower mean fibroblastic sleeve weight and a 66% shorter mean fibroblastic sleeve length compared to the untreated control at 14 days. By 30 days, compared to untreated control, the chlorhexidine-peripherally inserted central catheter showed 81% lower mean fibroblastic sleeve weight with 75% shorter mean fibroblastic sleeve length, the fluoro-oligomer-peripherally inserted central catheter showed 54% lower mean sheath weight with 40% shorter mean fibroblastic sleeve length, and the poly 2-methoxyethyl acrylate-peripherally inserted central catheter had 41% lower mean fibroblastic sleeve weight with 57% lower fibroblastic sleeve length. CONCLUSION:: Among the three anti-thrombogenic peripherally inserted central catheter technologies, the chlorhexidine-peripherally inserted central catheter had the smallest fibroblastic sleeves, followed by the fluoro-oligomer-peripherally inserted central catheter, poly 2-methoxyethyl acrylate-peripherally inserted central catheter, and control peripherally inserted central catheter.

In vivo evaluation of the HeartWare MVAD Pump.

OBJECTIVE: The current design trend for left ventricular assist devices (LVADs) is miniaturization, which aims to increase the treatable patient population and enable new treatment indications by reducing surgical trauma and the complications associated with device implantation. The MVAD Pump (HeartWare Inc, Framingham, MA) is a small, axial VAD that uses magnetic and hydrodynamic impeller technology and incorporates wide helical flow channels to minimize shear stress. In this study, we implanted the MVAD Pump in an ovine model to evaluate device hemocomaptiblity, biocompatibility, performance, and safety. METHODS: The MVAD Pump was implanted in an ovine model (n = 9) for 90 days. The pump was implanted through a thoracotomy and secured to the LV apex with a gimbaled sewing ring, which allowed for intraoperative adjustment of the insertion depth and angle of the inflow cannula. Serum analytes and coagulation parameters were analyzed at specific intervals throughout the study period. Pump flow, speed, and power were recorded daily to monitor device performance. Sheep were electively euthanized at 90 days for pathologic and histologic analysis. RESULTS: In this study, results demonstrated the safety, reliability, hemocompatability, and biocompatibility of the MVAD Pump. Nine animals were implanted for 90 ± 5 days. No complications occurred during surgical implantation. Seven of the 9 animals survived until elective sacrifice. Each sheep that survived to the scheduled explant appeared physically normal, with no signs of cardiovascular or other organ compromise. The 2 sheep that were euthanized early showed no evidence of device-related issues. CONCLUSIONS: The MVAD Pump was successfully implanted through a thoracotomy and demonstrated excellent hemodynamic support with no device malfunctions throughout the study period.

Percutaneous implantation of an intraventricular device for the treatment of heart failure: experimental results and proof of concept.

BACKGROUND: A percutaneous system to implant a ventricular partitioning device (VPD) has been developed to partition the left ventricular (LV) cavity for treating regional wall motion abnormalities associated with post-left anterior descending (LAD) infarction, dilated left ventricle, and systolic dysfunction. The hemodynamic effects of this novel approach were evaluated in an ovine model with an anteroapical infarction created by a coil placed in the LAD. METHODS AND RESULTS: LV anteroapical infarction (MI) was induced in 10 animals. The VPD device was implanted at 6 weeks after MI in 5 animals. The hemodynamic status of each animal was evaluated at 30 weeks post-MI in treated ("VPD+MI" group, n=5) and nontreated ("MI" group, n=5). The comparison of end-point hemodynamic variables shows a significantly smaller end-systolic LV volume in the animals receiving the implant (70.1+/-9.0 mL in "VPD+MI" group vs. 102.9+/-10.3 mL in "MI" group, P < .02), improved ejection fraction (46.9+/-5.2% in "VPD+MI" group vs. 34.7+/-6.8% in "MI" group, P < .04) and preserved cardiac output (5.2+/-0.7 L/min in "VPD+MI" group vs. 5.0+/-1.8 L/min in "MI" group, P=NS), suggesting more efficient mechanical performance of the LV with the implanted VPD. CONCLUSIONS: A significant reduction in LV volumes and corresponding improvement in LV function occurred after device implantation indicating a potential beneficial effect of this new device in treatment of post MI LV dilation.

Resuscitating hypothermic dogs after 2 hours of circulatory arrest below 6 degrees C.

BACKGROUND: Ultraprofound hypothermia may have a place in trauma rescue and resuscitation. We describe resuscitation of dogs after asanguineous perfusion and circulatory arrest of 2 hours at 2 degrees to 4 degrees C. METHODS: Nine dogs were cooled using a bypass apparatus and their circulating blood replaced with bicarbonated Hextend (Abbott, North Chicago, IL). Perfusion was continued to 2 degrees to 4 degrees C, and 60 mL of 2 mol/L KCl and 20 mL of 50% MgSO(4).7H(2)O were infused intra-arterially, and circulation was arrested for 2 hours. The dogs were then rewarmed, transfused, defibrillated, weaned from bypass, and allowed to awaken. Preoperative and postoperative biochemistry and hematology were compared. RESULTS: Six dogs recovered fully. One of these dogs died of an infection 2 weeks later. Three other dogs never recovered because of technical or procedural difficulties. Biochemical and hematologic parameters were normal by 3 weeks. CONCLUSION: Hypothermic blood substitution with Hextend allows resuscitation after 2 hours of ice-cold circulatory arrest in dogs.