Evaluation of resuscitative endovascular balloon occlusion of the aorta catheter placement and comparison to resuscitative thoracotomy with aortic clamping in cadaver dogs.

OBJECTIVE: To describe placement of an aortic occlusion catheter in aortic zone 1 (Z1) and aortic zone 3 (Z3) in dogs and to compare time to placement in these zones with and without external chest compressions (ECC). Additional evaluations of time to placement in Z1 with time for resuscitative thoracotomy with aortic clamping (RT-AC) were performed. DESIGN: Prospective ex vivo study. SETTING: University teaching hospital. ANIMALS: Ten canine cadavers. INTERVENTIONS: Ten cadaver dogs were obtained from client donation after euthanasia. Cadavers were randomized to have balloon catheter placement into the right or left femoral artery via cutdown, with or without ECC. The xiphoid was used as an external anatomical landmark for Z1, and the spinous process of the 5th lumbar vertebra was used for Z3. Balloon placement was confirmed with radiography. Time to balloon placement in Z1 and Z3 and time to RT-AC were recorded. MEASUREMENTS AND MAIN RESULTS: Median body weight was 23.5 kg (9-40 kg). Median time to Z1 placement was 6.6 minutes (4.6-12.4 minutes) with ECC and 6.9 minutes (3.3-13.1 minutes) without ECC and was not statistically different (P = 0.5). Median time to RT-AC was 1 minute (0.6-1.4 minutes), which was significantly faster than time to balloon placement in Z1 with or without ECC (P = 0.004 and P = 0.002, respectively). CONCLUSIONS: Endovascular balloon occlusion of the aorta can be achieved by cutdown with and without ECC, but RT-AC is faster. Successful balloon position in Z1 could be achieved with knowledge of external anatomical landmarks, but landmarks for Z3 need further study.

Balloon catheter occlusion of the maxillary, internal, and external carotid arteries in standing horses.

OBJECTIVE: To assess the feasibility of balloon catheter occlusion of the internal carotid artery (ICA), external carotid artery (ECA), and maxillary artery (MA) in standing horses. STUDY DESIGN: Experimental and clinical cases series. ANIMALS: Eight healthy horses (phase 1) and 11 clinical cases (phase 2). METHODS: Occlusions were performed on standing horses under sedation and local anesthesia. In phase 1, four horses underwent bilateral ICA balloon catheter occlusion, and four horses underwent balloon catheter occlusion of the ECA and MA. In phase 2, horses were treated by occlusion of ICA (n = 7), ECA (n = 2), or ECA and ICA (n = 2). RESULTS: Internal carotid artery occlusion was successful in seven of eight and seven of nine arteries in phases 1 and 2, respectively. The procedures lasted 53 and 50 minutes, respectively, and catheters were inserted over 13 ± 0.7 cm (mean ± SD). External carotid artery occlusion was successful in seven of seven and four of four arteries in phases 1 and 2, respectively, with mean durations of 31 and 26 minutes, respectively, and a mean distance of catheter insertion of 11.9 cm. Maxillary artery occlusion was successful in five of seven arteries (phase 1), with a mean surgical duration of 47 minutes and a mean distance of catheter insertion of 42.8 cm. CONCLUSION: Balloon catheter occlusion of the ICA, ECA, and MA was achieved in most standing horses. CLINICAL SIGNIFICANCE: Balloon catheter occlusion in standing horses provides an alternative to prevent or treat hemorrhage related to guttural pouch mycosis, particularly in horses in which general anesthesia might pose a risk.

Placement of a balloon for resuscitative endovascular balloon occlusion of the aorta without fluoroscopic guidance in canine cadavers.

OBJECTIVE: To determine whether a balloon for resuscitative endovascular balloon occlusion of the aorta (REBOA) could be accurately placed in the descending aorta between the left subclavian and celiac arteries (zone I) by using external anatomic landmarks in dogs. STUDY DESIGN: Cadaver study. SAMPLE POPULATION: Fifteen canine cadavers of 3 weight categories (10-20, 20-30, and ≥ 30 kg). METHODS: Percutaneous catheterization of the femoral artery was attempted under ultrasonographic guidance; when unsuccessful, an arterial cutdown was performed to place an introducer sheath. Distance was measured between the introducer sheath and the target region, located ventral to the epaxial muscles at the level of the 12th thoracic vertebra. The balloon was advanced the measured distance, and placement was confirmed with fluoroscopy. The volume of iohexol solution required to inflate balloons was recorded. Histopathology was performed on the aortas of the first 5 dogs. RESULTS: Three catheters were placed under ultrasonographic guidance. Balloons were successfully placed into zone I in 15 of 15 cadavers. Balloons were inflated with a median 0.4 mL/kg (range, 0.21-0.67) of iohexol solution. Minor changes were identified in 2 of 5 dogs examined with histopathology (linear defects in 1 dog, small focal dissection in the other). CONCLUSION: A balloon for REBOA was consistently placed in the target zone I without fluoroscopic guidance. CLINICAL SIGNIFICANCE: Fluoroscopy may not be required for zone I REBOA in dogs. Additional studies are warranted to evaluate the feasibility of REBOA in clinical dogs with hemoperitoneum.

Location is everything: The hemodynamic effects of REBOA in Zone 1 versus Zone 3 of the aorta.

OBJECTIVES: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging technology to augment proximal blood pressure during the resuscitation of patients with noncompressible torso hemorrhage. Currently, placement choice, supraceliac (Zone 1) versus infrarenal (Zone 3) aorta, depends on injury patterns, but remains a highly debated topic. We sought to compare the proximal hemodynamic support provided by Zone 1 versus Zone 3 REBOA placement and the degree of hemodynamic instability upon reperfusion following intervention. METHODS: Eighteen anesthetized swine underwent controlled hemorrhage of 25% total blood volume, followed by 45 minutes of Zone 1 REBOA, Zone 3 REBOA, or no intervention (control). They were then resuscitated with shed blood, aortic balloons were deflated, and 5 hours of critical care ensued prior to euthanasia. Physiologic parameters were recorded continuously, and blood was drawn for analysis at specified intervals. Significance was defined as p < 0.05. RESULTS: There were no significant differences between groups at baseline or during the initial 30 minutes of hemorrhage. During the intervention period, average proximal MAP was significantly greater in Zone 1 animals when compared with Zone 3 animals (127.9 ± 1.3 vs. 53.4 ± 1.1 mm Hg) and greater in Zone 3 animals when compared with control animals (42.9 ± 0.9 mm Hg). Lactate concentrations were significantly higher in Zone 1 animals (9.6 ± 0.4 mmol/L) when compared with Zone 3 animals (5.1 ± 0.3 mmol/L) and control animals (4.2 ± 0.8 mmol/L). CONCLUSIONS: In our swine model of hemorrhagic shock, Zone 3 REBOA provided minimal proximal hemodynamic support when compared with Zone 1 REBOA, albeit with less ischemic burden and instability upon reperfusion. In cases of impending hemodynamic collapse, Zone 1 REBOA placement may be more efficacious regardless of injury pattern, whereas Zone 3 should be reserved only for relatively stable patients with ongoing distal hemorrhage.

Clinical Characteristics of Adult Dogs More Than 5 Years of Age at Presentation for Patent Ductus Arteriosus.

BACKGROUND: The median age at presentation for dogs with patent ductus arteriosus (PDA) is <6 months of age, and closure is associated with a decrease in heart size and increased survival time, which are not well described in older dogs. OBJECTIVES: To describe the clinical characteristics of dogs with PDA ≥5 years of age at the time of presentation to a veterinary referral hospital. ANIMALS: 35 client-owned dogs. METHODS: Retrospective case series. RESULTS: PDA was diagnosed at a median age of 7.4 years (range, 5.1-12.3 years). Females represented 23/35 (65.7%) of the patients. Concurrent heart disease included degenerative mitral valve disease (DMVD; 13), arrhythmias (11), pulmonary hypertension (7), and other congenital defects (2). Cardiomegaly was documented in the majority of dogs consisting of left ventricular enlargement (91%) and left atrial enlargement (86%). Median vertebral heart size in 24 dogs was 12.9 (range, 10.7-18.2). The PDA shunt direction was left-to-right in 33 and bidirectional in 2 dogs. Closure was performed in 26 dogs, including 4 with pulmonary hypertension. In 10 dogs receiving furosemide pre-operatively for management of heart failure, furosemide was discontinued (8) or the dosage decreased (2) at the time of discharge. CONCLUSIONS AND CLINICAL IMPORTANCE: Adult dogs can present with a left-to-right shunting PDA that results in cardiomegaly and clinical signs that can improve or resolve with PDA closure. This improvement is also apparent in dogs with PDA complicated by DMVD. Pulmonary hypertension that does not result in complete right-to-left shunting should not be considered a contraindication to closure.

Collateral circulation in ferrets (Mustela putorius) during temporary occlusion of the caudal vena cava.

OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes. ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females). PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later. RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O. CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

Patent ductus arteriosus occlusion in small dogs utilizing a low profile Amplatz® canine duct occluder prototype.

OBJECTIVES: To develop procedural methodology and assess the safety, utility and effectiveness of a low profile Amplatz(®) canine duct occluder (ACDO) prototype in dogs deemed too small to undergo ductal occlusion with the commercially-available ACDO device. ANIMALS: Twenty-one dogs with left-to-right shunting patent ductus arteriosus (PDA). Dogs were ≥1.5 kg but considered too small to accommodate a 6 Fr catheter or 4 Fr sheath within the femoral artery. METHODS: Prospective canine study using a low profile ACDO prototype delivered through a 4 Fr catheter via a femoral arterial approach. Procedural methods, fluoroscopy time, perioperative complications, and residual ductal flow were evaluated, and angiographic ductal morphology and dimensions were tabulated. RESULTS: All 21 dogs underwent successful ductal occlusion using the prototype device, 4 Fr catheter, and right femoral artery approach. No perioperative complications or device embolization occurred. The median minimal ductal diameter was 1.9 mm (range, 0.4-3.4), and the median device size deployed was 4 mm (range, 3-6). Complete ductal occlusion was noted in 17 dogs (81%) on post-deployment angiography. Twenty dogs (95%) had no residual flow on echocardiography performed the following day. In the 17 dogs (81%) that returned for a long-term (≥3months) follow-up evaluation, all had complete ductal occlusion based on echocardiography. CONCLUSIONS: The low profile ACDO prototype is a safe and effective method of PDA occlusion in the small dog. The deployment procedure appears of similar technical difficulty to the commercially available ACDO.

Pulmonary artery dissection in eight dogs with patent ductus arteriosus.

OBJECTIVES: To describe a series of dogs with pulmonary artery dissection and patent ductus arteriosus (PDA). ANIMALS: Eight dogs. METHODS: Retrospective case series. RESULTS: Pulmonary artery dissection was diagnosed in 8 dogs, 3 were Weimaraners. Four dogs presented in left-sided congestive heart failure, 4 presented for murmur evaluation and without clinical signs, and 1 presented in right-sided congestive heart failure. In 7 dogs the dissection was first documented concurrent with a diagnosis of uncorrected PDA. In the other dog, with pulmonary valve stenosis and PDA, the dissection was observed on autopsy examination 17 months after balloon pulmonary valvuloplasty and ductal closure. Median age at presentation for the 7 dogs with antemortem diagnosis of pulmonary artery dissection was 3.5 years (range, 1.5-4 years). Three dogs had the PDA surgically ligated, 2 dogs did not undergo PDA closure, 1 dog failed transcatheter occlusion of the PDA with subsequent surgical ligation, 1 dog underwent successful transcatheter device occlusion of the PDA, and 1 dog had the PDA closed by transcatheter coil delivery 17 months prior to the diagnosis of pulmonary artery dissection. The 2 dogs that did not have the PDA closed died 1 and 3 years after diagnosis due to heart failure. CONCLUSIONS: Pulmonary artery dissection is a potential complication of PDA in dogs, the Weimaraner breed may be at increased risk, presentation is often in mature dogs, and closure of the PDA can be performed and appears to improve outcome.

Balloon occlusion of the caudal vena cava for vascular contrast studies as an aid to intravascular coil embolisation for the treatment of intrahepatic portosystemic shunts in three dogs.

CASE REPORT: Three dogs were treated with fluoroscopically guided coil embolisation of intrahepatic portosystemic shunts. A large-diameter vascular occlusion balloon was used to improve the vascular contrast studies required to perform this procedure. This technique improved identification of vascular structures and allowed completion of the procedures without the need for digital subtraction angiography. CLINICAL SIGNIFICANCE: Interventional radiological procedures are an emerging area of veterinary medicine and procedural modifications may help expand their use in clinical practice.

[Patent ductus arteriosus in the dog: a retrospective study of clinical presentation, diagnostics and comparison of interventional techniques in 102 dogs (2003-2011)]. / Persisterende ductus arteriosus bij de hond: een retrospectieve studie naar klinische presentatie, diagnostiek, en vergelijking van toegepaste therapeutische mogelijkheden bij 102 honden (2003-2011).

A left-to-right shunting patent ductus arteriosus (PDA) is a common congenital heart defect in dogs. If it is left uncorrected, life expectancy in most cases is decreased due to the development of left-sided congestive heart failure. The aim of this study was to describe the dogs diagnosed with PDA in the Utrecht University Companion Animal Clinic from 2003 to 2011. The medical records of 102 patients were retrieved, and the clinical presentation and outcome of PDA closure by surgical ligation or transarterial catheter occlusion (TCO) were reviewed. In the TCO group, the result of coiling was compared with the placement of an Amplatz Canine Duct Occluder (ACDO). A predisposition to PDA was found in the German Brak, Stabyhoun, and Schapendoes. Dogs treated with surgical ligation were significantly older and heavier than those treated with TCO; within the TCO group, dogs treated with ACDO were significantly older and heavier The initial success rate (complete disappearance of the audible murmur in a patient that survived the procedure) was not significantly different between the different treatment modalities. Major complications were more common with surgical ligation, but the incidence of minor complications was not significantly different. There was no diference in survival between dogs treated with surgical ligation and dogs treated with TCO. This study shows a previously unreported predisposition to PDA in certain breeds. Both surgical ligation and TCO are suitable techniques for PDA closure, although major complications were more common with surgical ligation. ACDO appears to be the method with the least complications and thus can be considered the safest method.

Feasibility of percutaneous catheterization and embolization of the thoracic duct in dogs.

OBJECTIVE: To develop and determine the feasibility of a novel minimally invasive technique for percutaneous catheterization and embolization of the thoracic duct (PCETD) in dogs and to determine thoricic duct TD pressure at rest and during short-term balloon occlusion of the cranial vena cava (CrVC). ANIMALS: Fifteen 7- to 11-month-old healthy mixed-breed dogs. PROCEDURES: Efferent intestinal lymphangiography was performed, and the cisterna chyli was punctured with a trochar needle percutaneously under fluoroscopic guidance. When access was successful, a guide wire was directed into the TD through the needle and a vascular access sheath was advanced over the guide wire. Thoracic duct pressure was measured at rest and during acute balloon occlusion of the CrVC. The TD was then embolized cranial to the diaphragm with a combination of microcoils and cyanoacrylate or ethylene vinyl alcohol. RESULTS: Successful puncture of the cisterna chyli with advancement of a wire into the TD was possible in 9 of 15 dogs, but successful catheterization was possible in only 5 of 9 dogs. Acute balloon occlusion of the CrVC led to a substantial TD pressure increase in 4 of 4 dogs, and embolization of the TD was successful in 4 of 4 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: PCETD can successfully be performed in healthy dogs; however, this minimally invasive technique cannot currently be recommended for routine treatment of chylothorax, in part because of the technically demanding nature of the procedure. An increase in jugular venous pressure led to an increase in TD pressure, potentially predisposing some dogs to developing chylothorax.

Percutaneous occlusion of a muscular ventricular septal defect with an Amplatzer muscular VSD occluder.

Ventricular septal defects are a relatively common congenital cardiac disease that, when severe, can be associated with substantial morbidity and mortality. Several minimally invasive methods of repair have been described in the human literature. This report describes the first case of percutaneous closure of a naturally occurring muscular septal defect using an Amplatzer occluder in a dog affected by concurrent pulmonic stenosis. Based on this experience catheter-based occlusion of muscular ventricular septal defects is a feasible option in dogs. Further studies are necessary to identify the attributes and limitations of the technique.

Minimally invasive per-catheter patent ductus arteriosus occlusion in dogs using a prototype duct occluder.

BACKGROUND: Per-catheter patent ductus arteriosus (PDA) occlusion in dogs with devices intended for humans is associated with technical difficulties, high rates of procedure abandonment, device migration, and residual ductal flow. HYPOTHESIS: Use of a custom-made canine duct occluder (Amplatz Canine Duct Occluder, ACDO) would be feasible in dogs of varying weights and somatotypes and effective in occluding a wide range of PDA shapes and sizes. ANIMALS: Eighteen client-owned dogs of various breeds with PDA. Weights ranged from 3.8 to 32.3 kg (median, 17.8 kg), and angiographic minimal ductal diameters ranged from 1.1 to 6.9 mm (median, 3.7 mm). Ductal morphologies included types IIA, IIB, and III. METHODS: Per-catheter PDA occlusion with the ACDO was performed in all dogs. Persistent or recurrent ductal flow was assessed at the end of the procedure by angiography and at 1 day, 3 months, and >or=12 months after the procedure by echocardiography. RESULTS: Successful ACDO placement was achieved in all 18 dogs. One dog required a 2nd procedure with a larger ACDO after the 1st device migrated to the pulmonary vasculature. Complete occlusion was confirmed in 17 of 18 dogs during the procedure, as well as at 1 day and 3 months after the procedure, and in 12 of 13 dogs evaluated at >or=12 months after the procedure. CONCLUSIONS AND CLINICAL IMPORTANCE: Per-catheter PDA occlusion in dogs with the ACDO is feasible and effective in dogs of a wide range of weights and somatotypes and with PDAs of varying shapes and sizes.

Transcatheter embolisation of patent ductus arteriosus using an Amplatzer vascular plug in six dogs.

OBJECTIVES: The objective of this study was to assess the feasibility of transcatheter embolisation of a patent ductus arteriosus using an Amplatzer vascular plug (Amplatzer Medical UK) in six dogs. METHODS: The Amplatzer vascular plug is a self-expandable, cylindrical device attached to a delivery cable. In all the dogs, the device was delivered transvenously. Successful device implantation was defined as firm anchorage of the device squarely within the distal part of the ductus arteriosus with no intra- or postoperative dislodgement. Successful occlusion of the ductus arteriosus occurred if a disappearance of the continuous murmur was achieved 24 hours after placement of the Amplatzer vascular plug. RESULTS: The age of the dogs ranged from 16 weeks to 7.5 years. Their weights ranged from 2.9 to 27.6 kg (median 6 kg). Two dogs had congestive heart failure before embolisation. Successful device implantation was achieved in all dogs. Successful occlusion of the ductus arteriosus was achieved in four of the six dogs. Complications included mild lameness, residual shunting, and bruising and pruritus around the surgical wound site. At follow-up, two dogs had a continuous murmur and one required treatment for congestive heart failure. CLINICAL SIGNIFICANCE: This technique may represent a clinically effective and less expensive alternative to the use of an Amplatzer duct occluder (Amplatzer Medical UK) in dogs with medium-sized patent ductus arteriosus. Further investigations are required to fully evaluate its efficacy and safety in various sizes and types of patent ductus arteriosus, and to determine the optimal device size in relation to the size of the ductus.