Shorter Premature Atrial Complex Coupling Interval Leads to Mechanical Dysfunction, Fibrosis, and AF in Swine.

Background: We have previously shown that dyssynchronous premature atrial complexes (PACs) from the lateral left atrium (LA) lead to greater atrial mechanical dysfunction, remodeling, and sustained atrial fibrillation (AF) than synchronous PACs from the interatrial septum. However, the impact of PAC coupling interval (CI) on atrial remodeling is unclear.

Objectives: This study sought to explore the effect of PAC CI on atrial mechanics and remodeling in the swine model.

Effect of Epicardial Pulsed Field Ablation Directly on Coronary Arteries.

Background: The unique tissue selectivity of pulsed field ablation (PFA) allows for minimizing collateral damage to the nerves/esophagus. However, the safety profile of epicardial PFA on coronary arteries (CAs) has not been well defined.

Objectives: This study sought to evaluate the effect of epicardial PFA directly on CAs in a swine model.

Pulsed Field Ablation of Left Ventricular Myocardium in a Swine Infarct Model.

Background: Pulsed field ablation (PFA) leads to cell death by irreversible electroporation. There are limited data about PFA lesion characteristics in the ventricle, particularly in the presence of myocardial scar.

Objectives: This study sought to evaluate the lesion characteristics of PFA and radiofrequency energy (RFA) in healthy and infarcted left ventricular (LV) myocardium in swine.

Evaluating Radioactive Analogs of Doxorubicin to Quantify ChemoFilter Binding and Whole-Body Positron Emission Tomography/Magnetic Resonance Imaging for Drug Biodistribution.

Purpose: To evaluate radiolabeled doxorubicin (Dox) analogs as tracers of baseline Dox biodistribution in vivo during hepatic intra-arterial chemotherapy and to assess the efficacy of ChemoFilter devices to bind Dox in vitro.

Materials And Methods: In an in vitro static experiment, [fluorine-18]N-succinimidyl 4-fluorobenzoate ([F]SFB) and [fluorine-18]fluorobenzoyl-doxorubicin ([F]FB-Dox) were added to a beaker containing a filter material (Dowex cation exchange resin, single-stranded DNA (ssDNA) resin, or sulfonated polymer coated mesh). In an in vitro flow model, [F]FB-Dox was added into a Dox solution in phosphate-buffered saline, and the solution flowed via a syringe column containing the filter materials.

Effect of Low-Frequency Therapeutic Ultrasound on Induction of Nitric Oxide in CKD: Potential to Prevent Acute Kidney Injury.

Introduction: Post-contrast acute kidney injury (PC-AKI) develops in a significant proportion of patients with CKD after invasive cardiology procedures and is strongly associated with adverse outcomes.

Objective: We sought to determine whether increased intrarenal nitric oxide (NO) would prevent PC-AKI.

Methods: To create a large animal model of CKD, we infused 250 micron particles into the renal arteries in 56 ± 8 kg pigs.

Endovascular Ion Exchange Chemofiltration Device Reduces Off-Target Doxorubicin Exposure in a Hepatic Intra-arterial Chemotherapy Model.

Purpose: To determine if endovascular chemofiltration with an ionic device (ChemoFilter [CF]) can be used to reduce systemic exposure and off-target biodistribution of doxorubicin (DOX) during hepatic intra-arterial chemotherapy (IAC) in a preclinical model.

Materials And Methods: Hepatic IAC infusions were performed in six pigs with normal livers. Animals underwent two 10-minute intra-arterial infusions of DOX (200 mg) into the common hepatic artery.

Wireless Resonant Circuits Printed Using Aerosol Jet Deposition for MRI Catheter Tracking.

Interventional magnetic resonance imaging (MRI) could allow for diagnosis and immediate treatment of ischemic stroke; however, such endovascular catheter-based procedures under MRI guidance are inherently difficult. One major challenge is tracking the tip of the catheter, as standard fabrication methods for building inductively coupled coil markers are rigid and bulky. Here, we report a new approach that uses aerosol jet deposition to three-dimensional (3-D) print an inductively coupled RF coil marker on a polymer catheter.

An Intravascular Tantalum Oxide-based CT Contrast Agent: Preclinical Evaluation Emulating Overweight and Obese Patient Size.

Purpose To compare the CT imaging performance of a carboxybetaine zwitterionic-coated tantalum oxide (TaCZ) nanoparticle CT contrast agent with that of a conventional iodinated contrast agent in a swine model meant to simulate overweight and obese patients. Materials and Methods Four swine were evaluated inside three different-sized adipose-equivalent encasements emulating abdominal girths of 102, 119, and 137 cm. Imaging was performed with a 64-detector row CT scanner at six scan delays after intravenous injection of 240 mg element (Ta or I) per kilogram of body weight of TaCZ or iopromide.

Interventional magnetic resonance imaging guided carotid embolectomy using a novel resonant marker catheter: demonstration of preclinical feasibility.

To assess the visualization and efficacy of a wireless resonant circuit (wRC) catheter system for carotid artery occlusion and embolectomy under real-time MRI guidance in vivo, and to compare MR imaging modality with x-ray for analysis of qualitative physiological measures of blood flow at baseline and after embolectomy. The wRC catheter system was constructed using a MR compatible PEEK fiber braided catheter (Penumbra, Inc, Alameda, CA) with a single insulated longitudinal copper loop soldered to a printed circuit board embedded within the catheter wall. In concordance with IACUC protocol (AN103047), in vivo carotid artery navigation and embolectomy were performed in four farm pigs (40-45 kg) under real-time MRI at 1.

Endovascular MR-guided Renal Embolization by Using a Magnetically Assisted Remote-controlled Catheter System.

Purpose To assess the feasibility of a magnetically assisted remote-controlled (MARC) catheter system under magnetic resonance (MR) imaging guidance for performing a simple endovascular procedure (ie, renal artery embolization) in vivo and to compare with x-ray guidance to determine the value of MR imaging guidance and the specific areas where the MARC system can be improved. Materials and Methods In concordance with the Institutional Animal Care and Use Committee protocol, in vivo renal artery navigation and embolization were tested in three farm pigs (mean weight 43 kg ± 2 [standard deviation]) under real-time MR imaging at 1.5 T.

Endovascular biopsy: Technical feasibility of novel endothelial cell harvesting devices assessed in a rabbit aneurysm model.

The lack of safe and reliable methods to sample vascular tissue in situ limits discovery of the underlying genetic and pathophysiological mechanisms of many vascular disorders, including aneurysms. We investigated the feasibility and comparable efficacy of in vivo vascular endothelial cell sampling using a spectrum of endovascular devices. Using the rabbit elastase carotid aneurysm model we evaluated the performance of existing aneurysmal coils, intracranial stents, and stent-like devices to collect vascular endothelial cells.

The effect of a peptide-modified thermo-reversible methylcellulose on wound healing and LV function in a chronic myocardial infarction rodent model.

Myocardial infarction is the main contributor to heart failure. In this study we examined whether modification of a thermo-reversible cellulose-based polymer with extracellular-matrix derived functional groups could promote wound healing and improve cardiac function in a chronic rodent model of ischemic cardiomyopathy. To beneficially influence the microenvironment of the injured myocardium, we conjugated either the RGD peptide or the HepIII peptide to the polymer.

The variable functional effects of the pacing site in normal and scarred ventricles.

Background: The pacing site has been shown to influence functional improvement with cardiac resynchronization therapy. We evaluated the effects of the pacing site on left ventricular (LV) function in an animal model.

Methods And Results: Equilibrium radionuclide angiography was acquired in sinus rhythm (NSR) and with ventricular pacing, from three pacing sites in seven normal and eight infarcted dogs.

Safety and efficacy of endovascular cooling and rewarming for induction and reversal of hypothermia in human-sized pigs.

Background And Purpose: Numerous studies indicate that mild hypothermia provides substantial neuroprotection. However, current systems transfer insufficient heat to rapidly vary core temperature. We thus evaluated the safety and efficacy of endovascular cooling and rewarming for the induction and reversal of hypothermia.

Effect of endovascular cooling on myocardial temperature, infarct size, and cardiac output in human-sized pigs.

Mild hypothermia reduces myocardial infarct size in small animals; however, the extent of myocardial protection in large animals with greater thermal mass remains unknown. We evaluated the effects of mild endovascular cooling on myocardial temperature, infarct size, and cardiac output in 60- to 80-kg isoflurane-anesthetized pigs. We occluded the left anterior descending coronary artery for 60 min, followed by reperfusion for 3 h.