Retrieval of Chronically Implanted Dual-chamber Leadless Pacemakers in an Ovine Model.

Background: The clinical utilization of leadless pacemakers (LPs) as an alternative to traditional transvenous pacemakers is likely to increase with the advent of dual-chamber LP systems. Since device retrieval to allow LP upgrade or replacement will become an important capability, the first such dual-chamber, helix-fixation LP system (Aveir DR; Abbott, Abbott Park, IL) was specifically designed to allow catheter-based retrieval. In this study, the preclinical performance and safety of retrieving chronically implanted dual-chamber LPs was evaluated.

Preclinical safety and electrical performance of novel atrial leadless pacemaker with dual-helix fixation.

Background: Complications associated with transvenous pacemakers, specifically those involving the lead or subcutaneous pocket, may be avoided with leadless pacemakers (LPs). The safety and efficacy of single-chamber right ventricular LPs have been demonstrated, but their right atrium (RA) use poses new design constraints.

Objectives: The purpose of this study was to evaluate the implant success, electrical performance, and safety of a novel RA LP design in benchtop and preclinical studies.

A novel suprachoroidal microinvasive glaucoma implant: in vivo biocompatibility and biointegration.

Background: A major challenge for any glaucoma implant is their ability to provide long-term intraocular pressure lowering efficacy. The formation of a low-permeability fibrous capsule around the device often leads to obstructed drainage channels, which may impair the drainage function of devices. These foreign body-related limitations point to the need to develop biologically inert biomaterials to improve performance in reaching long-term intraocular pressure reduction.

Pathology Approaches to Determine Safety and Efficacy of Cardiac Ablation Catheters.

Cardiac electrophysiology utilizes nonimplantable, catheter-based devices for diagnosis and treatment of arrhythmias as well as electroanatomical mapping of cardiac chambers. Gross pathology and histopathological assessments in preclinical studies play critical roles in determining the safety and efficacy of cardiac ablation systems used to treat tachyarrhythmias. The pathologist must assess ablation sites, adjacent structures and organs, and downstream organs to characterize the effects of the ablation treatment and determine whether adverse local reactions, collateral injury, or downstream thromboembolism are present.

Balloons and Stents and Scaffolds: Preclinical Evaluation of Interventional Devices for Occlusive Arterial Disease.

Atherosclerosis places a significant burden on humankind; it is the leading cause of mortality globally, and for those living with atherosclerosis, it can significantly impact quality of life. Fortunately, treatment advances have effectively reduced the morbidity and mortality related to atherosclerosis, with one such modality being percutaneous intervention (PCI) to open occluded arteries. Over the 40-year history of PCI, preclinical models have played a critical role in demonstrating proof of concept, characterizing the in vivo behavior (pharmacokinetics, degradation) and providing a reasonable assurance of biologic safety of interventional devices before entering into clinical trials.

Evaluation of absorbable PLA nasal implants in an ovine model.

Objective: To examine biocompatibility and absorption profile of a poly (L-lactide-co-D,L-lactide) 70:30 nasal implant.

Methods: In an ovine model, 66 rod-shaped absorbable implants were placed in 11 nasal dorsa. The sheep were sacrificed at 1.

Percutaneous Retrieval of Implanted Leadless Pacemakers: Feasibility at 2.5 Years Post-Implantation in an In Vivo Ovine Model.

Objectives: This in vivo ovine study describes the feasibility and safety of retrieving implanted leadless pacemakers (LPs).

Background: Although LPs have been shown to be removable soon after implantation, there are no data on the feasibility of removing chronically implanted LPs.

Methods: This study was performed in 2 phases.

Feasibility and efficacy of percutaneously delivered leadless cardiac pacing in an in vivo ovine model.

Introduction: In this in vivo ovine study, we describe the course of pacing and sensing parameters during follow-up as well as the gross and histopathological features at the implant site of the recently described leadless cardiac pacemaker (LCP).

Methods And Results: All sheep underwent LCP implantation in the right ventricular (RV) apex. Serial pacing/sensing thresholds were assessed.

Comparison of scanning electron microscopy and optical coherence tomography for imaging of coronary bifurcation stents.

Background: Optical coherence tomography (OCT) is a new intracoronary imaging modality that has excellent resolution and image quality and has been used to image neointimal coverage after stent implantation. OCT has been compared to histologic, intravascular ultrasound, and scanning electron microscopy (SEM) studies. However, OCT has not been compared with SEM for imaging stent coverage over side branches.

Effective method to remove wound bacteria: comparison of various debridement modalities in an in vivo porcine model.

Background: Debridement is one of the crucial steps for successful wound care. In addition to removing necrotic tissue, debridement has been shown to reduce wound-associated bacteria that delay healing. Using an in vivo porcine model, we compared the effects of various methods of debridement, including hydrosurgery and plasma-mediated bipolar radiofrequency ablation (PBRA), on bacterial removal and wound healing.

Catheter-based renal sympathetic denervation: chronic preclinical evidence for renal artery safety.

Background: Renal sympathetic hyperactivity is associated with hypertension, a leading cause of mortality worldwide. Renal sympathetic denervation via the Symplicity Catheter System has been shown to decrease blood pressure by 33/11 mmHg by 6 months, with no radiofrequency (RF)-related adverse sequelae visible by CT/MR angiography or renal duplex ultrasound 6 months after the procedure. Here, we present preclinical work predating those clinical results.

Evaluation of a novel ventricular support device with defibrillation capabilities in canine and porcine animal models.

Introduction: Sudden death is prevalent in heart failure patients. We tested an implantable ventricular support device consisting of a wireform harness with one or two pairs of integrated defibrillation electrode coils.

Methods And Results: The device was implanted into six pigs (36-44 kg) through a subxiphoid incision.

A placebo controlled, dose-ranging, safety study of allogenic mesenchymal stem cells injected by endomyocardial delivery after an acute myocardial infarction.

Aims: Although mesenchymal stem cells (MSCs) show promising signs in reducing myocardial infarct (MI) size, the safety of endomyocardial delivery and the most efficacious dose is unknown.

Methods And Results: Three days after MI, female Yorkshire swine (25-32 kg, age 2 months, n = 32) were randomized to endomyocardial delivery of one of three MSC doses (2.4 x 10(7), 2.