Radiation dose during interventional cardiology procedures: portable C-arm vs. a new generation fluoroscopy system.

INTRODUCTION: Occupational exposure to ionizing radiation poses health risks for veterinary interventionalists. There are limited veterinary studies evaluating radiation dose in the cardiac catheterization laboratory. The purpose of this study was to report direct radiation dose exposure to patients during common interventional cardiology procedures and compare these doses between two fluoroscopy units. ANIMALS: One hundred and fifty-four client-owned dogs. MATERIALS AND METHODS: Patient dose during procedures using a portable C-arm were retrospectively analyzed and compared to those performed in a contemporary interventional suite. Fluoroscopy equipment, procedure type, operator, patient weight, fluoroscopy time, dose area product, and air kerma were recorded and statistically modeled using univariable and multivariable linear regression to evaluate the effect of each factor. RESULTS: Patient dose population (154 dogs), comprised 61 patent ductus arteriosus occlusions, 60 balloon pulmonary valvuloplasties, and 33 pacemaker implantations. Patient dose was significantly lower in the group utilizing a newer generation fluoroscopy unit vs. the group utilizing an older portable C-arm, positively correlated with patient weight, and highest during balloon pulmonary valvuloplasties compared to patent ductus arteriosus occlusions or pacemaker implantations (all P<0.010). DISCUSSION: Newer fluoroscopy systems can be equipped with technologies that improve image quality while reducing patient dose and radiation exposure to interventional personnel. CONCLUSIONS: We documented a significant reduction in patient radiation dose using a newer fluoroscopy system as compared to an older portable C-arm for interventional cardiology procedures in animals. Improved knowledge of patient radiation dose factors may promote better radiation safety protocols in veterinary interventional cardiology.

Transcatheter closure of aneurysmal perimembranous ventricular septal defect with the canine duct occluder in two dogs.

Congenital membranous ventricular septal aneurysm has been reported in dogs and can be associated with a perimembranous ventricular septal defect (VSD). The windsock-like ventricular septal aneurysm is formed by tissue of the membranous ventricular septum and portions of the septal leaflet of the tricuspid valve. We report two dogs that underwent transcatheter closure of perimembranous VSD associated with membranous ventricular septal aneurysm using a commercial device marketed for transcatheter closure of patent ductus arteriosus, the canine duct occluder. Partial closure was achieved in the first dog with reduction in left heart dimensions documented on echocardiography both at one day and nine months after procedure. In the second dog, three-dimensional transesophageal echocardiography, cardiac computed tomography, and a three-dimensionally printed whole heart model were used to evaluate feasibility for transcatheter device closure. Complete closure of the VSD was subsequently achieved. Both cases had good short- to medium-term outcomes, no perioperative complications were observed, and both dogs are apparently healthy and receiving no cardiac medications at 34 months and 17 months after procedure. Transcatheter attenuation of perimembranous VSD with membranous ventricular septal aneurysm is clinically feasible using the canine duct occluder, and multimodal cardiac imaging allows accurate assessment and planning prior to transcatheter intervention for structural heart disease in dogs.

Medial insertion of the patent ductus arteriosus characterized by computed tomography angiography in a cat and dog.

Surgical ligation of a left-to-right shunting patent ductus arteriosus was attempted in two animals. In both cases, a young cat and dog, ligation was complicated by poor visualization of the ductus resulting in unsuccessful ligation. Post-operatively, both the cat and dog underwent computed tomography angiography to characterize the location and morphology of the patent ductus arteriosus. In both cases, computed tomography angiography revealed a left-to-right shunting patent ductus arteriosus with an insertion location medial to the left pulmonary artery branch compared to the typical location. We hypothesize that this atypical location resulted in a difficult surgical visualization from the left thoracotomy approach. Transvenous coil embolization of the duct from the external jugular vein was performed in both cases and resulted in successful occlusion. Variations in the medial-lateral insertion of the ductus arteriosus may have consequences for surgical intervention. If an atypical location of a patent ductus arteriosus is suspected on transthoracic echocardiography, computed tomography angiography prior to ligation may be useful to further define ductal location and help guide the surgical approach.

Transvenous occlusion of patent ductus arteriosus in a domestic chicken (Gallus gallus).

A 2.5-year-old intact female Marans domestic chicken was presented for lethargy, open beak breathing, and hyporexia. Echocardiography noted left atrial and left ventricular enlargement and computed tomography angiography revealed a type III left-sided patent ductus arteriosus. Retrograde catheterization of the ductus was performed via percutaneous access of the right external jugular vein, and transvenous ductal occlusion was achieved using an 8-mm Amplatzer™ Vascular Plug 4. Transient bradycardia and hypotension occurred during right heart catheterization, which were successfully treated with atropine and epinephrine. A two-week follow-up postoperative cardiac computed tomography scan confirmed appropriate placement of the occluder within the ductus, and echocardiography demonstrated reduced left heart size. The chicken showed an improvement in clinical signs and remains apparently well six months after the intervention. This report describes the computed tomographic findings of a patent ductus arteriosus in an avian species, minimally invasive transvenous closure of this congenital anomaly with a low-profile occlusion device, and the associated challenges and considerations specific to cardiac intervention in an avian patient.

Dilatable pulmonary artery banding for ventricular septal defect: surgical technique and case report of three cats.

Pulmonary artery banding (PAB) is a viable but underreported palliative option for hemodynamically significant ventricular septal defect in small animals. A significant challenge associated with PAB is judging the degree of band tightening, which can be further complicated when animals are immature and still growing at the time of PAB. If a pulmonary artery band is overtightened or becomes progressively too tight after surgery, the result can be reversal of shunt flow with potentially devastating consequences. Placement of a band that could be percutaneously dilated using a balloon catheter affords a minimally invasive option for partially or completely relieving the band should it become too tight after PAB. This report describes a surgical technique for placement of a dilatable pulmonary artery band, reviews guidelines for tightening the band, and reports the outcome of three cats undergoing the procedure. All three cats showed evidence of reduced hemodynamic load after PAB for a period of up to three years after PAB.

Association between Survival Time and Changes in NT-proBNP in Cats Treated for Congestive Heart Failure.

BACKGROUND: Reductions in N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations after treatment have been associated with improved survival in people with congestive heart failure (CHF), but have not been reported in cats with CHF. OBJECTIVES: To evaluate changes in NT-proBNP concentrations in cats with CHF after treatment and determine whether serial NT-proBNP measurements provide prognostic information. ANIMALS: Thirty-one client-owned cats. METHODS: Prospective, observational study in cats with new onset CHF secondary to cardiomyopathy. Concentrations of NT-proBNP were measured within 4 hours of admission to the hospital, on the day of discharge, and at re-evaluation 7-10 days later. RESULTS: Median NT-proBNP concentrations decreased significantly from admission (1,713 pmol/L [range, 160-3,784 pmol/L]) to discharge (902 pmol/L [range, 147-3,223 pmol/L]); P = .005) and from admission to re-evaluation (1,124 pmol/L [range, 111-2,727 pmol/L]; P = .024). Median survival time was 109 days (range, 1-709 days), with 5 cats still alive at the time of analysis. Cats with a larger percent decrease in NT-proBNP from admission to discharge had a longer survival time (P = .048). Cats with evidence of active CHF at the time of re-evaluation (P = .010) and cats whose owners had difficulty administering medications (P = .045) had shorter survival times. CONCLUSIONS AND CLINICAL IMPORTANCE: Cats with a larger percent decrease in NT-proBNP during hospitalization and no evidence of CHF at the time of re-evaluation had longer survival times. Additional studies are needed to determine whether NT-proBNP can help guide treatment in cats with CHF.

Pathology of hepatomas and other liver abnormalities in English sole (Parophrys vetulus) from the Duwamish River estuary, Seattle, Washington.

Liver abnormalities were found, by gross and histopathologic examination, in 92% of the English sole (Parophrys vetulus) from the Duwamish River Estuary, Seattle, Washington. Hepatomas were found in 32% (20 of 62) of the English sole. Other observed liver aberrations included increased fatty vacuolation, congestion, structure disarray, increased size and number of melanin-macrophage centers, centrolobular fatty degeneration and necrosis, increased amounts of perivascular connective tissue, intercellular melanin deposits, and hepatocellular hypertrophy often associated with the presence of bizarre nuclei and/or multiple nucleoli. Livers evidencing microscopic lesions were usually discolored. Livers containing hepatomas were often mottled yellow or tan and brown; occasionally, hepatomas were visible as tan or white nodules. Although the cause(s) of the liver abnormalities has not been conclusively identified, chemical analyses of Duwamish River English sole have detected polychlorinated biphenyl (PCB) levels of about 1.5 ppm (dry wt) in total body tissue. Many of the above-mentioned abnormalities, with the exception of hepatomas, have been observed in fish exposed to PCB's.