Canine Duct Research Articles

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

ObjectivesTo 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. AnimalsTwenty-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. MethodsProspective 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. ResultsAll 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. ConclusionsThe 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.

Use of Amplatz® canine duct occluder for closing a patent ductus arteriosus in a small-sized dog

A 2-year-old intact female pomeranian dog presented dyspnea, labored breathing, cough, exercise intolerance, machinery heart murmur, and precordial thrill. A left-to-right patent ductus arteriosus (PDA) was diagnosed based on two-dimensional echocardiography, thoracic radiography, electrocardiography, and blood work. An angiography was performed to accurately evaluate the size and shape of the duct. An interventional approach for transcatheterial occlusion of the PDA was achieved using an Amplatz® Canine Duct Occluder (ACDO), which is a commercially available ductal occluding device. Due to the limited size of the dog’s femoral artery, a device smaller [125% of minimal ductal diameter (MDD); recommended size: 150~200% of MDD] than recommended was mounted. After placement of the ACDO, precordial thrill and continuous heart murmur disappeared, and the patient was discharged the next day after stabilization with O2 supply. Upon follow up examination, dyspnea, labored breathing, cough, exercise intolerance, and cardiomegaly were improved with no complications after the procedure. The ACDO was well maintained in position. This case represents successful clinical application of the Amplatz® Canine Duct Occluder to achieve closure of a PDA using a slightly smaller device than the recommended size.

Delayed embolization of an Amplatz® canine duct occluder in a dog

A 5-year old, 5.8 kg, castrated male Pomeranian was diagnosed with a type IIa patent ductus arteriosus (PDA) with a minimal ductal diameter of 3.5 mm and ampulla width of 7.1 mm based on angiographic assessment. A 6 mm Amplatz® Canine Duct Occluder (ACDO) was deployed within the PDA. Once deployed, the device assumed it's native shape and back-and-forth maneuvering was performed with the delivery cable to assess device stability. Device position and complete occlusion were confirmed with both angiography and transesophageal echocardiography prior to and after release of the device. The device location was confirmed within the ductus arteriosus by echocardiography prior to discharge. The dog was discharged with instructions for strict activity restriction. Two days after discharge, the dog was left unsupervised in the backyard and shortly afterwards was found coughing with severe respiratory distress. The dog was evaluated at an emergency hospital and thoracic radiographs documented embolization of the ACDO to the main pulmonary artery along with a severe alveolar pattern throughout the right lung fields. Shortly after obtaining thoracic radiographs, the dog experienced cardiopulmonary arrest with unsuccessful resuscitation. This case describes a possible complication of transcatheter PDA occlusion with an ACDO, which has not been previously reported. An incident report, or catalog of adverse events with these devices, may prove useful in identifying additional fatal complications that others may have encountered, but are not reported in the literature. The report of this complication emphasizes the importance of strict activity restriction after device placement in dogs.

Clinical forum: canine pancreatitis and biliary duct obstruction

Part 3: The surgeon's perspective The first two of these three articles have looked at the issues of management of extrahepatic biliary tract obstruction from diagnostic and therapeutic view points. By the time the case has been transferred to the surgical team, the patient may still be in a critical condition. Extra hepatic biliary duct obstruction (EHBDO) has a number of systemic physiologic effects, other than the obvious clinical sign of jaundice ( Figure 1 ). Patients may be inappetant, and in a cachectic condition, they may have an anaemia of chronic disease, intestinal sloughing or haemorrhage, hepatic compromise, coagulopathy, endotoxaemia, decreased myocardial contractility, acute tubular necrosis and be at risk of biliary tract rupture.

Clinical Forum: canine pancreatitis and biliary duct obstruction

Part 2: The radiologist's perspective This clinical forum will review pancreatic disease in dogs, primarily focusing on those patients that go on to develop obstruction of the biliary tree. A series of commonly asked questions relating to pancreatitis and concurrent biliary tract obstruction will be asked of a panel of specialists with varying views expressed! In the August 2013 issue of Companion Animal, a further article on this topic will be published giving both a surgeon's perspective on canine pancreatitis and biliary duct obstruction.

Clinical Forum: canine pancreatitis and biliary duct obstruction

Part 1: The medic's perspective This clinical forum will review pancreatic disease in dogs, primarily focusing on patients that go on to develop obstruction of the biliary tree. A panel of specialists will be asked a series of commonly asked questions relating to pancreatitis and concurrent biliary tract obstruction, with varying views expressed! Over the coming weeks, further articles on this topic will be published, giving both an imager's and surgeon's perspective on canine pancreatitis and biliary duct obstruction.

Comparative Anatomy of the Human and Canine Efferent Tear Duct System – Impact of Mucin MUC5AC on Lacrimal Drainage

Purpose: To investigate the histomorphology of the canine tear drainage system and to show the distribution of mucin MUC5AC within the tissue.Methods: Conjunctiva and tear drainage systems of 19 long-nosed dogs were investigated histologically and ultrastructurally. The tissues were stained with eight different antibodies reactive against less glycosylated and highly-glycosylated MUC5AC. Results were compared with findings in human tissue received from 12 body donors.Results: Except for a distinctly longer nasolacrimal duct and several accessory openings of the duct into the nasal cavity, the morphology of the canine tear drainage system is very similar to that of humans. MUC5AC in less- and highly-glycosylated forms was present in the conjunctival tissue of dogs as well of humans. Within the tear sac and the nasolacrimal duct only less-glycosylated MUC5AC could be found in dogs and in human.Conclusions: These findings demonstrate that the canine tear drainage system is very similar to its human equivalent. In particular the distribution of MUC5AC, supposed to play an important role within the pathogenesis of dry eye syndrome (DES), is the same as in humans. Therefore the canine model seems to be an appropriate model for further DES research.

Occlusion Devices and Approaches in Canine Patent Ductus Arteriosus: Comparison of Outcomes

A comparison of transvascular occlusion methods for closing patent ductus arteriosus (PDA) in dogs has not been done. To determine if clinically important differences exist between the approaches and devices currently used. A total of 112 client-owned dogs with left-to-right shunting PDA. Retrospective study. Records from dogs that underwent attempted transvascular PDA occlusion from January 2006 to December 2009 were examined. Dogs were placed into 4 groups: Group 1: Amplatz Canine Duct Occluder (ACDO) (transarterial) - 36 dogs; Group 2: Gianturco or MReye Flipper Detachable Embolization (Flipper) coil (transarterial) - 38 dogs; Group 3: Amplatzer Vascular Plug (AVP) (transarterial) - 23 dogs; Group 4: Flipper coil (transvenous) - 15 dogs. The overall success rate of the procedures was high (92%) with comparable success rates among groups (87-97%). There were significantly fewer complications (P < .0001) in dogs receiving an ACDO than in the remaining groups (3% for ACDO versus 26-33% for the other groups). Fluoroscopy time for the transvenous method was significantly longer (median, 13 minutes) than for the other groups (median, 6 minutes) (P < .0001). Severity of residual flow 24 hours postprocedure was significantly less in the ACDO group than in the remaining groups (P = .0001-.05). The ACDO appears superior in ease of use, complication rate, and completeness of occlusion. The remaining limiting factor with this device is patient size. Until a smaller ACDO device is marketed, coils remain the only choice for interventional closure in very small dogs.

An update on transcatheter occlusion of patent ductis arteriosus in dogs

A patent ductus arteriosus, PDA, is one of the most common congenital cardiac defects in dogs. Previously a variety of methods was used to repair a PDA. These methods have now largely been superseded by the use of the relatively new Canine Amplatz Duct Occluder. This article details the advantages of the new device – these include increased ease of repair, reduced length of procedure and reduced incidence of residual flow through the ductus after repair.

Utility of Transesophageal Echocardiography for Transcatheter Occlusion of Patent Ductus Arteriosus in Dogs: Influence on the Decision-Making Process

Appropriate device selection for transcatheter occlusion of patent ductus arteriosus (PDA) is essential to procedural success. To determine if transesophageal echocardiography (TEE) influences device selection for PDA occlusion and to report benefits, limitations, and complications associated with TEE. Twenty-two client-owned dogs with left-to-right shunting PDA. PDA dimensions were obtained via transthoracic echocardiography (TTE) and then TEE followed by angiography. Based solely on information from TTE and angiography, an initial device type and size were selected. After initial device selection, TEE measurements were disclosed and changes in device selection were recorded. After device release, angiography, TEE, or both were performed to assess occlusion. An Amplatz canine duct occluder (ACDO) was securely positioned and released in 21 dogs and an embolization coil was deployed in 1 dog. Based on TEE evaluation, initial selected device type was unchanged but ACDO size was changed in 3 dogs. TEE was utilized throughout the procedure allowing real time visualization of device deployment, release and assessment of closure in 17 dogs. No complications occurred related to TEE. Complete PDA closure was achieved in all dogs. TEE provided anatomic information regarding PDA morphology that closely approximated angiographic ductal dimensions while aiding in device deployment, release and confirmation of closure. We conclude that TEE provides complementary anatomical and intraprocedural information and is well tolerated in dogs.

Transarterial ductal occlusion using the Amplatz ® Canine Duct Occluder in 40 dogs

Objectives Describe the result of patent ductus arteriosus (PDA) occlusion using the Amplatz ® Canine Duct Occluder (ACDO) in 40 dogs. Animals, material and methods Records of the first 41 dogs at Texas A&M University in which ductal occlusion with an ACDO was attempted were reviewed. Results Appropriate device release was achieved in 40 of 41 dogs. Post-release angiography in 39 dogs documented complete occlusion in 27 dogs, trivial residual flow in 7, mild residual flow in 1 and moderate residual flow in 4; angiography was not recorded in one dog. The following day transthoracic color Doppler echocardiography documented complete occlusion in all 40 dogs. One dog required a larger device than could be deployed through the largest sheath accommodated by the femoral artery and the PDA was subsequently closed by surgical ligation. Conclusions Ductal occlusion using an ACDO has a high rate of initial and 24-h complete occlusion. Ductal occlusion using an ACDO is a safe and efficacious therapy for PDA in dogs. This report confirms the positive clinical outcome of the original report in a large cohort of dogs.

Erratum

Journal of Veterinary Internal MedicineVolume 22, Issue 3 p. xxviii-xxviii Open Access Erratum This article corrects the following: Minimally Invasive Per-Catheter Patent Ductus Arteriosus Occlusion in Dogs Using a Prototype Duct Occluder T. P. Nguyenba, A. H. Tobias, Volume 22Issue 1Journal of Veterinary Internal Medicine pages: 129-134 First Published online: February 14, 2008 First published: 10 July 2008 https://doi.org/10.1111/j.1939-1676.2008.00102.xAboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat In the recently published manuscript by Nguyenba and Tobias,1 reference 16 was inadvertently omitted. Here is that reference: Nguyenba TP, Tobias AH. The Amplatz® canine duct occluder: A novel device for patent ductus arteriosus occlusion. J Vet Cardiol 2007;9: 109–117. We apologize for this error. Reference 1 Nguyenba TP, Tobias AH. Minimally invasive per-catheter patent ductus arteriosus occlusion in dogs using a prototype duct occluder. J Vet Int Med 2008; 22: 129– 134. Volume22, Issue3May–June 2008Pages xxviii-xxviii ReferencesRelatedInformation

Minimally Invasive Per‐Catheter Patent Ductus Arteriosus Occlusion in Dogs Using a Prototype Duct Occluder

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. 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. 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. 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. 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. 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.

The Amplatz ® canine duct occluder: A novel device for patent ductus arteriosus occlusion

The Amplatz ® canine duct occluder (ACDO) is a nitinol mesh device with a short waist that separates a flat distal disc from a cupped proximal disc. The device is designed to conform to the morphology of the canine patent ductus arteriosus (PDA). PDA dimensions are determined by angiography, and a guiding catheter is advanced into the main pulmonary artery via the aorta and PDA. An ACDO with a waist diameter approximately twice the angiographic minimal ductal diameter (MDD) is advanced via the catheter using an attached delivery cable until the flat distal disc deploys within the main pulmonary artery. The partially deployed ACDO, guiding catheter, and delivery cable are retracted until the distal disc engages the pulmonic ostium of the PDA. With the delivery cable stabilized, the catheter is retracted to deploy the waist across the pulmonic ostium and cupped proximal disc within the ductal ampulla. Tension on the delivery cable is released, and correct ACDO positioning and stability are confirmed by observing that the device assumes its native shape, back-and-forth maneuvering of the delivery cable, and a small contrast injection made through the guiding catheter. The delivery cable is detached and removed with the guiding catheter. To assess for any residual ductal flow, an angiogram is performed at the conclusion of the procedure, followed by Doppler echocardiography at 1 day and 3 months post-procedure. PDA occlusion in dogs with the ACDO is straightforward and extremely effective across a wide range of body weights, somatotypes, MDDs, and ductal morphologies.

Microvascularization of the Canine Hepatic Ducts

The angioarchitecture of the proximal and distal segments of the hepatic duct in the dog was investigated by means of vascular corrosion casts under a scanning electron microscope. The results of observations indicated a change of the pattern of vascularization of the hepatic duct along with the increasing distance of the hepatic duct from the liver and increasing diameter of the duct. In the proximal hepatic duct, the main blood vessels run along the duct as a pair of supplying arteriole and voluminous collecting venule, while in the distal segments of the hepatic duct on the opposite margin of the duct two vascular triads were observed, composed of two venules and one medial arteriole. On the surface of both segments of the hepatic duct, there are well-anastomosed outer venous plexuses. In the distal segments of the hepatic duct, the outer venous plexus accompanies a fine outer arterial rete. Observations of the intramural network indicate the presence of single terminal arterioles running to mucosa and supplying a subepithelial capillary network. Differences were observed in the blood drainage from the mucosa, as in the proximal segment of the hepatic duct single post-capillary venules are found, while in the distal segment in the mucosa a well-developed mucosal venous plexus is formed. In the well-developed venous system of the hepatic duct no valves were observed.

Regeneration of the endothelium in the canine and feline thoracic duct

Recent improvements in microsurgical techniques on lymphatic vessels facilitated the treatment of lymphoedema. But it is becoming clear that a successful treatment of lymphatic disease has to be based on knowledge of ongoing processes. Particularly, one of the important and unclear issue is cellular mechanisms of lymphatic regeneration. The regeneration of endothelial and the smooth muscle cells of the thoracic duct has been experimentally tested in vivo. The canine and feline thoracic duct was cryo-injured using 3 mm-based copper rod. Damaged endothelial cells remained attached to the substrate and lost unthrombogenecy within 48 hr. Adjacent EC restored the defect within 3 days by migration and proliferation. We observed that on the first day, the endothelial monolayer included some elongated multinuclear cells with blind silver lines whereas, on the third day, they were replaced by a population of smaller ECs with numerous mitoses. Organization of the monolayer was restituted within 7 days. The newly formed endothelium was similar to regenerating endothelium of arteries. In general, the clot that appeared at the zone of injury on the second day was dissolved by the third day. Occasionally, the dense polymorphic clot adhered to the wall and caused a delay in reendothelisation. Complete restitution of the tunica media which involved migration and proliferation mechanisms accompanied the endothelium regeneration.

The Tunica media of the Thoracic Duct Contains a Heterogeneous Population of Muscle Cells

The three-dimensional cyto-architecture and ultrastructure of cells composing the different regions of the tunica media of canine and feline thoracic ducts (ThD) were investigated by scanning and transmission electron microscopy. The tunica media of the intervalvular regions consists of 2-4 layers of circulatory oriented ribbon-like smooth muscle cells (SMCs) of the contractile phenotype. Spot-like membrane contacts similar to gap junctions were observed between SMCs. In the parietal part of the valve's sinus (PPVS), modified SMCs containing large lipid droplets were found. Occasionally, in the upper thoracic part of the ThD in the PPVS, we observed cardiomyocyte-like cells (CMLCs) arranged as circularly oriented bundles. Frequent interdigitation contacts were formed between SMCs and CMLCs, suggesting a possible involvement of the latter cell type in pacemakers activity in the ThD.

Free and conjugated catecholamines and serotonin in canine thoracic duct lymph: effects of feeding

The source and fate of sulfoconjugated catecholamines present in plasma are not known. Sulfated norepinephrine has been shown to overflow together with free norepinephrine from a typical peripheral neuroeffector junction. Some released free norepinephrine is removed via the lymphatic system, but it is not known whether sulfated catecholamines are removed similarly. Serotonin, another biogenic amine, is released from the enterochromaffin cells into portal blood. The aims of the present study were to determine whether conjugated catecholamines and serotonin could be detected in thoracic duct lymph of dogs and to compare concentrations in lymph with those in samples of portal blood collected before and after the dogs were fed. A method is described for the extraction and purification of free and conjugated catecholamines and serotonin from lymph. In lymph and in plasma, there were similar concentrations of free (0.2-0.4 ng/ml) and conjugated (0.1-0.2 ng/ml) norepinephrine and of conjugated dopamine (0.2-1.0 ng/ml). The concentrations of free serotonin were much lower in lymph (0.1-0.2 ng/ml) than in portal blood (100-200 ng/ml). Small amounts of conjugated serotonin (0.1-0.4 ng/ml) were detected in lymph but were not detected in plasma. Feeding caused increases in concentration of conjugated dopamine in lymph and in plasma and small increases in the output of free norepinephrine and free and conjugated serotonin in lymph.

Role of pancreatic vagal and sympathetic afferents in the reflex increase of renal sympathetic activity after injection of bile into the canine pancreatic duct

Role of pancreatic vagal and sympathetic afferents in the reflex increase of renal sympathetic activity after injection of bile into the canine pancreatic duct

Canine bile contains anticrystallization factors that inhibit precipitation of calcium carbonate*1, *2

Previous studies have strongly suggested that human bile contains a substance(s) that interferes with the precipitation of calcium phosphate and carbonate from solution. These studies, however, did not distinguish between calcium binding by biliary constituents resulting in decreased calcium carbonate saturation (alterations in solution thermodynamics) and true inhibition of calcium salt precipitation by kinetic factors. Because our recent studies have shown that canine common duct bile is always supersaturated with calcium carbonate (thermodynamically at risk for precipitation), we hypothesized that it must contain kinetic factors that inhibit formation and/or growth of calcium carbonate crystals. Effects of canine bile, bovine albumin and the bile salt taurocholate on calcium carbonate precipitation were studied in highly supersaturated solutions of calcium carbonate that spontaneously undergo rapid precipitation. Measured free ionized calcium concentrations, [Ca++], and calculated calcium carbonate saturation indices were compared in test solutions and controls to evaluate the thermodynamic effects of test solutions on the degree of saturation in the assay system. It is shown that addition of only 0.2 ml of normal canine gallbladder bile to the assay system (a 1:101 dilution of biliary components) abolished precipitation. A lesser inhibitory effect (a decrease in the rate of precipitation) was observed when gallbladder bile was diluted but was lost after 10-fold dilution. Canine common duct bile caused a decrease in the rate of precipitation similar to diluted gallbladder bile. In contrast, sodium taurocholate (250 mmol/L), the major bile salt in the dog, and albumin (1.5 gm/L), the most abundant protein in bile, had only a minimal inhibitory effect.(ABSTRACT TRUNCATED AT 250 WORDS)