Monitoring ecological recovery of reclaimed wellsites: Protocols for quantifying recovery on forested lands.

We developed a scientifically robust and financially sustainable monitoring protocol to enable a consistent assessment of ecological recovery of physical, chemical, and biological indicators at certified reclaimed industrial wellsites in forested lands in noutheastern Alberta. Using the developed protocols, data can be generated from measurement of soil, vegetation, and landscape indicators at reclaimed wellsites and adjacent reference sites. We selected the appropriate vegetation, soil, and habitat indicators for a long-term reclamation monitoring program and have provided sampling protocols for the selected indicators here. The protocols may be used to identify and prioritize indicators of reduced ecosystem health and to track ecological recovery of reclaimed sites over time. The development of these integrated monitoring protocols is a first step towards successful and consistent long-term monitoring to assess ecological recovery of certified wellsites in Alberta. These protocols can be applied to wellsites and other similar sized disturbances in other forested regions too.

Initial clinical experience with the VentrAssist left ventricular assist device: the pilot trial.

BACKGROUND: The VentrAssist (VA) is a novel, continuous flow left ventricular assist device (LVAD). The purpose of this trial was to investigate the safety and efficacy of the VA in elderly patients with end-stage heart failure. METHODS: In this prospective trial, patients requiring circulatory support either as destination therapy (DT) or as a bridge to transplant (BTT) were implanted with a VA device. RESULTS: Between June 2003 and August 2006, 9 elderly patients (mean age 65 years) were implanted. The median support time was 454 (range 73 to 977) days for the DT and 35 (range 26 to 508) days for the BTT cohort. All patients survived implantation; 30-day mortality was 22% (n = 2). The adverse event profile was encouraging, with no embolic neurologic events and minimal sepsis. Cumulative trial support time was 7.3 patient-years. CONCLUSIONS: The VentrAssist shows promise as a safe and reliable "third-generation" VAD. Having demonstrated potential as a DT and prolonged BTT device, extended clinical trials are warranted.

First clinical implant of the VentrAssist left ventricular assist system as destination therapy for end-stage heart failure.

The VentrAssist device left ventricular assist system, designed for permanent implantation, is a novel centrifugal pump with a hydrodynamically suspended rotor. The first human implant was into a 72-year-old man with New York Heart Association (NYHA) class IV heart failure due to idiopathic dilated cardiomyopathy. The implant and recovery were uneventful, and the patient survives at 17 months, is NYHA class II, and lives at home. This device shows promise in end-stage heart failure for permanent implantation and bridge to transplantation.

Implantation of the VentrAssist Implantable Rotary Blood Pump in sheep.

The VentrAssist Implantable Rotary Blood Pump (IRBP) is a hydrodynamically suspended, electromagnetically driven, centrifugal blood pump that provides continuous flow of up to 10 L/min at 3,000 rpm. In vivo studies in sheep were conducted to assess system design and performance. Surgery involved thoracotomy with subdiaphragmatic pump placement. Cannulae were transdiaphragmatic, with inflow in the left ventricular apex and outflow anastomosed to the descending aorta. Animals had no anticoagulation or antiplatelet therapy after surgery and no prophylactic antibiotics after recovery. Twelve sheep were supported for 622 pump days. Estimated pump flow ranged from 1 to 5.5 L/min at 1,800 to 2,000 rpm using 2.5 to 4.5 W. There was no clinical evidence of hemolysis or cardiovascular, renal, or hepatic dysfunction. Adverse outcomes included kinking/disconnection of the outflow cannula caused by the graft bend relief (n = 4), which was addressed through cannula redesign. Pump electrical malfunction (n = 4), caused by a silicone potting compound, was corrected using a neutral curing potting material. Surgical/husbandry issues (n = 2) also were addressed. The VentrAssist IRBP provides high flow at low rotational speed and power consumption. Further trials are in progress in advance of in vivo studies of the safety and efficacy of the final system.

Initial in vivo experience of the VentrAssist implantable rotary blood pump in sheep.

VentrAssist (VentrAssist Division, Ventracor Ltd., Chatswood, NSW, Australia) has developed an implantable centrifugal blood pump with an integrated rotor and impeller that is hydrodynamically suspended. Bench testing has been used to assess the performance of the pump under a broad range of operating conditions. This study examined the performance of the pump in vivo up to 90 days implantation. Pumps were implanted via a left lateral thoracotomy. The inflow cannula was inserted at the apex of the left ventricle. The outflow cannula was anastomosed to the descending thoracic aorta. Eighteen implants were performed. Poor recovery from surgery was the main cause of early study termination. These studies demonstrate the suitability of the animal model for evaluation of the VentrAssist rotary blood pump. Further in vivo studies prior to preclinical trials are in progress.