Canine Duct Occluder Research Articles

Comparative transcatheter occlusion of patent ductus arteriosus: multicenter collaborative study across pediatric and veterinary cardiology centers

Introduction/ObjectiveTranscatheter therapeutics have revolutionized treatment of patent ductus arteriosus (PDA). Greater understanding of corrective interventions across species can advance best practices, protocols, and outcomes while minimizing adverse events. The objective of this study was to describe characteristics and outcomes in children and dogs undergoing transcatheter PDA occlusion. Animals, Materials and MethodsThis was a multicenter, retrospective cohort study from two pediatric and three veterinary centers. Demographics, procedural characteristics, and outcomes were assessed. ResultsData included 202 children and 106 dogs treated from July 2019 to June 2021. Forty-five (23%) children and 19 (18%) dogs had congestive heart failure prior to catheterization. Transvenous and transarterial approaches for deployment were most used in children and dogs, respectively. All children had percutaneous vascular access compared to 17 (16%) dogs. Intraprocedural anticoagulation was standard for children (100% of 165 reported), but not for dogs (2/103). The median (interquartile range) pulmonary ostium diameter in children was 2.2 mm (1.5–3.0 mm) and 3.0 mm (2.0–4.2 mm) in dogs when all body sizes were considered (P<0.001). Amplatzer™ Duct Occluder was most commonly used in children (64/202, 32%); the Amplatz® Canine Duct Occluder was used in dogs (96/100, 96%). Closure was manual compression in all children, whereas vessel ligation was most used in dogs (74/104, 73%). Successful device deployment was achieved in 197 (98%) children and 98 (93%) dogs (P=0.03). Major reasons for failure included device embolization in six (2.9%) children and PDA morphology concerns in four (3.8%) dogs. ConclusionsTranscatheter PDA occlusion is successful in children and dogs. Study data might be useful for optimizing transcatheter therapeutics and animal models for interventional cardiology.

Two- and three-dimensional transesophageal echocardiographic assessment and successful occlusion of a window-like patent ductus arteriosus in two dogs

A 16-month-old Labrador-Poodle cross (case 1) and a 3-month-old German shorthaired pointer (case 2) were referred for patent ductus arteriosus (PDA) occlusion. Two-dimensional transthoracic and two- and three-dimensional transesophageal echocardiography revealed a window-like PDA characterized by a wide and short ductus. Due to the atypical PDA morphology with no ampulla in case 1, ductal occlusion was attempted with non-canine-specific Amplatzer occluder devices. However, these were too small and failed to remain stable. Amplatz Canine Duct Occluder (ACDO) devices were used with success in both cases. Due to the defects' morphology, the proximal ACDO disc protruded into the aorta but there were no signs of obstruction to aortic blood flow 16 months (case 1) and 1 month (case 2) post-occlusion. We describe two cases of a window-like type PDA that were successfully occluded with an ACDO.

Transjugular Patent Ductus Arteriosus Occlusion in Seven Dogs Using the Amplatzer Vascular Plug II.

Simple SummaryThis study outlines the authors’ experience using the Amplatzer Vascular Plug II device for occlusion of patent ductus arteriosus (PDA) in dogs through a right transjugular approach, never before described in veterinary medicine for this purpose. The obtained results demonstrate that the use of the Amplatzer Vascular Plug II via a transvenous right jugular approach is a feasible and effective method, even in small-sized patients. The authors’ experience is that the transvenous approach is a safe and effective method for PDA occlusion in dogs. Furthermore, the right jugular approach provides easier and faster vascular access than the femoral one. The authors affirm that this approach, together with the properties of the Amplatzer Vascular Plug II and its wide size selection, potentially provide a novel method that can complement the current available methods for transcatheter PDA occlusion.Although vascular plugs for the closure of patent ductus arteriosus (PDA) have been validated in dogs, studies are lacking on its use as a first-choice device with a transjugular approach. The present case series describes the transvenous right jugular embolization of PDA using an Amplatzer Vascular Plug II in seven dogs of different ages, breeds, and body weights. Complete closure of the PDA was demonstrated in all cases. All dogs showed significant hemodynamic reduction of pulmonary overcirculation and left heart size after the procedure and at following echocardiographic check-ups. Transjugular PDA occlusion using an Amplatzer Vascular Plug II can thus be considered as a safe alternative to the arterial or venous femoral approach using an Amplatzer canine ductal occluder (ACDO), particularly in puppies with small femoral vessels.

Case Report: Aortic Regurgitation of Postocclusion and Long-Term Outcome Following PDA Correction in an Adult Dog

A 9-year-old intact female Maltese dog was admitted for further evaluation of previously diagnosed patent ductus arteriosus (PDA). The dog showed severe coughing and exercise intolerance. On physical examination, a grade VI/VI continuous heart murmur was auscultated. Thoracic radiography demonstrated cardiomegaly, pulmonary overcirculation, and moderate bronchointerstitial pattern. Echocardiography revealed severe dilation of the left ventricle and atrium, decreased left ventricular contractility, and left-to-right PDA. On electrocardiography (ECG), R amplitude was increased. Computed tomographic angiography revealed type IIA PDA. The serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration was >10,000 pmol/L. Transarterial occlusion was performed and the Amplatz® Canine Duct Occluder was successfully deployed. On echocardiography 48 h after the procedure, aortic regurgitation (AR) and residual ductal flow were noted. Long-term follow-up on clinical signs, physical examination, radiography, echocardiography, ECG, and serum NT-proBNP were evaluated until 30 months after correction of PDA. The clinical indices of physical examination, thoracic radiography, echocardiography, ECG, and serum NT-proBNP concentration were improved, although the postocclusion AR and residual ductal flow persisted. The dog followed up without clinical signs for 41 months following the correction. To our knowledge, this is the first case report to demonstrate quite a long time of follow-up (41 months) in an older dog with transarterial occlusion of PDA with postocclusion AR and residual flow.

Transcatheter closure of patent ductus arteriosus in 11 dogs and one cat after incomplete or aborted surgical ligation

ObjectiveTo describe the characteristics and outcomes of transcatheter patent ductus arteriosus (PDA) occlusion after incomplete or aborted surgical ligation in dogs and cats. AnimalsTwelve client-owned animals (11 dogs and one cat). Materials and methodsThis retrospective study describes data from animals with aborted or incomplete surgical PDA ligation that subsequently underwent transcatheter closure using endovascular methods. Patient demographics, reason for incomplete or aborted surgery, complications, and method of transcatheter occlusion were recorded. Data are presented as mean ± standard deviation or median (interquartile range), where appropriate. ResultsFor all cases, median age at surgery was 12.2 months (4.9–15.1 months) and at catheterization was 15.4 months (8.9–21.9 months), with 79 days (29–209 days) between surgical and interventional procedures. Median weight at catheterization was 4.5 kg (2.5–12.6 kg). Reasons for failed surgical ligation included hemorrhage during ductal dissection in seven dogs, residual flow in four dogs, and inability to identify the ductus in one cat. Transcatheter closure was successfully performed using a canine duct occluder in eight dogs, transarterial coil embolization in two dogs, and transvenous coil embolization in one dog and one cat. Metallic hemoclips partially obscured angiographic findings in three cases with prior surgical hemorrhage but did not prevent transcatheter closure. In all cases, ductal flow was successfully attenuated, with no or trace residual shunting on angiography and complete occlusion the following day on echocardiography. ConclusionsWhen surgery is unsuccessful, either owing to hemorrhage or residual flow, transcatheter closure of PDA is feasible, even in small patients.

Late recanalization after complete occlusion of patent ductus arteriosus in a Pembroke Welsh Corgi with von Willebrand disease

A 36‐month‐old female Pembroke Welsh Corgi with a cardiac murmur weighing 12.6 kg was referred to the Matsubara Animal Hospital cardiology service. Echocardiography revealed a patent ductus arteriosus. The dog underwent ductus arteriosus closure using an Amplatz Canine Duct Occluder. After the operation, we suspected coagulation and a platelet disorder because of the slightly increased haemorrhage during the operation, postoperative purpura around the surgical wound inside of the thigh, and dog breed, which is known to be commonly affected with von Willebrand disease (vWD). Subsequently, type 1 vWD was confirmed. Complete occlusion was achieved 1 month after the operation; however, 2 months after the operation, recanalization appeared. Recanalization progressed gradually; cardiac redilation was not detected 6 years after the operation. The late recanalization was most likely associated with vWD. In canine breeds pre‐disposed to developing vWD, pre‐operative testing may be indicated prior to patent ductus arteriosus occlusion, though the prevalence of vWD is rare.

Transarterial correction of patent ductus arteriosus in small dogs with the Amplatz™ Vascular Plug 4: A pilot study

ObjectivesDetermine if the Amplatz™ Vascular Plug 4 (AVP4) can be used to occlude left-to-right shunting patent ductus arteriosus (PDA) in dogs with inadequate arterial vascular access for the Amplatz Canine Duct Occluder (ACDO). AnimalsSix adolescent dogs with PDA whose femoral artery was too small for insertion of a 4 Fr vascular access sheath. Materials and methodsStandard femoral arterial vascular access and a 4 Fr diagnostic catheter were used to deploy an appropriately sized AVP4 into the PDA of each dog. Successful occlusion was defined as no residual ductal flow and determined by color Doppler echocardiography and angiography. ResultsThe AVP4 was successfully deployed, and complete occlusion of the PDA was achieved in all dogs. There were no complications encountered in any of the dogs. ConclusionsThe AVP4 is a viable option for the correction of PDA in dogs with inadequate arterial vascular access for the ACDO and should be considered as one of the options available for PDA correction in this challenging animal population.

Branham sign in dogs undergoing interventional patent ductus arteriosus occlusion or surgical ligation: a retrospective study.

Background:The Branham sign is a baroreceptor response that follows patent ductus arteriosus (PDA) closure. Although described in dogs following both interventional and surgical ductal closure, a direct comparison of the Branham sign elicited by these two techniques has not been made.Aim:Since closure with an Amplatz canine ductal occluder (ACDO) occurs over 10 minutes and surgical ligation (SL) is more rapid, we hypothesized that the Branham sign following occlusion of a PDA with an ACDO would be less severe than following SL.Methods:Clinical records of dogs diagnosed with left-to-right shunting PDA between 2008 and 2018 were retrospectively reviewed. Of 139 dogs undergoing PDA occlusion, only 41 dogs (ACDO n = 32, SL n = 9) were included after applying exclusion criteria. Heart rate (HR) and blood pressure (BP) from occlusion time (T0) until 30 minutes post occlusion (T30) were recorded. Signalment and anesthetic protocol were also recorded. The influence of age and weight on the hemodynamic variations was assessed. Hemodynamic variables and calculations were compared between and within groups using a repeated measures general linear model, and post hoc tests were applied if significance was identified.Results:A mild Branham sign was present in both groups, and hemodynamic changes were not significantly different between groups. In both groups, there was a significant decrease in HR (11 bpm, 5.3–16.3; p < 0.001) (10.4%, 5.4–15.5; p < 0.001) and increase in diastolic BP (9.5 mmHg, 3–16; p = 0.002) (23.5%, 7.1–39.9; p = 0.002), but systolic BP did not change significantly (p = 0.824). Age and weight did not influence Branham sign.Conclusion:The Branham sign in dogs is mild in both groups, lasts for at least 30 minutes, and is independent of the method of PDA closure.

Low profile vascular plug for transarterial occlusion of patent ductus arteriosus in small dogs.

BackgroundMinimally invasive transcatheter occlusion using Amplatz canine duct occluder (ACDO) is the treatment of choice for dogs with left‐to‐right shunting patent ductus arteriosus (PDA). However, in small dogs the femoral artery diameter is often too small to accommodate the guiding catheter required for ACDO deployment.ObjectiveDescribe the effectiveness of transarterial implantation of Amplatzer Vascular Plug 4 (AVP‐4), the only self‐expandable nitinol mesh occlusion device which can be implanted through a 4 French diagnostic catheter, in small dogs with left‐to‐right shunting PDA.AnimalsSeven client‐owned dogs.MethodsDescriptive case series. Dogs with hemodynamically relevant left‐to‐right shunting PDA and a femoral artery diameter less than 2.0 mm measured preoperatively with ultrasonography were prospectively enrolled.ResultsAngiography after releasing the device showed complete immediate PDA closure in 5 dogs, where the manufacturers' recommendation were strictly followed (30%‐50% device oversizing of the ductal ampulla's diameter). Trivial residual flow on angiography in the 6th dog, whose device was slightly undersized, had resolved on echocardiography within 2 hours after placement. Marked device undersizing in the 7th dog resulted in severe residual shunting, which necessitated the addition of a coil. In this dog, the AVP‐4 embolized into the pulmonary artery within 2 weeks after placement.Conclusions and Clinical ImportanceTransarterial implantation of AVP‐4 is a safe, effective and technically easy procedure for PDA occlusion in small dogs and offers a valuable alternative to coil implantation. Accurate PDA measurement and device sizing is essential to prevent residual shunting, inadvertent device embolization, and protrusion of the device into the aorta.

Anaesthetic management of a patent ductus arteriosus (PDA) occlusion using an Amplatz canine duct occluder (ACDO) in a dog

Patent ductus arteriosus (PDA) is one of the most common diagnosed congenital disease in dogs that usually causes heart failure and death unless corrected at a young age. A 2.5-year-old...

Anatomy, baseline characteristics, and procedural outcome of patent ductus arteriosus in German Shepherd dogs.

BackgroundGerman Shepherd dogs (GSD) are predisposed to developing patent ductus arteriosus (PDA) and are reportedly prone to type III (tubular) PDA anatomy. Dogs with type III anatomy are not considered favorable candidates for device‐based intervention.ObjectiveTo describe the PDA anatomy, baseline characteristics, and procedural outcome of GSD with PDA.AnimalsTwenty‐eight client‐owned GSD.MethodsRetrospective review of medical records of 28 GSD diagnosed with PDA that underwent surgical ligation or transcatheter device closure between 2007 and 2017.ResultsGerman Shepherd dogs with PDA often presented with clinical signs (50%), concurrent congenital heart disease (35.7%), and arrhythmias (29%). Dogs were typically mature at presentation (median age, 12.1 months) and evenly distributed by sex (57% female). The PDA anatomy was classified in 24 of 28 GSD, with type II anatomy being most common (21/24). Three dogs had unusual anatomy (type IV in 1, type V in 2). Median minimal ductal diameter (MDD) in this population was larger than previously reported in a mixed population and ranged between 4.4 and 4.9 mm depending upon imaging modality. Successful closure was achieved using an Amplatz canine duct occluder (ACDO) in 22 dogs or by surgical ligation in 6 dogs. No cases of type III anatomy were confirmed.Conclusions and Clinical ImportanceThe majority of GSD in this population had type II PDA anatomy that was amenable to ACDO deployment. Predisposition for large MDD and occasional, unusual PDA anatomy suggests that transesophageal echocardiography may be beneficial for optimal procedural planning in this breed.

Comparison of major complication and survival rates between surgical ligation and use of a canine ductal occluder device for treatment of dogs with left-to-right shunting patent ductus arteriosus.

OBJECTIVE To compare rates of major intraoperative complications and survival to hospital discharge between surgical ligation (SL) and canine ductal occluder (CDO) implantation for treatment of dogs with left-to-right shunting patent ductus arteriosus (PDA). DESIGN Retrospective cohort study. ANIMALS 120 client-owned dogs with left-to-right shunting PDA (62 treated by SL and 58 treated by CDO implantation). PROCEDURES Data were retrieved from medical records of included dogs regarding signalment, medical history, vertebral heart scale, preoperative echocardiographic findings, complications encountered during surgery, and durations of anesthesia and surgery (SL or CDO implantation). Data were compared between dogs treated by SL and those treated by CDO implantation. RESULTS Dogs treated by CDO implantation were significantly older and heavier than dogs treated by SL and had more pathological cardiac remodeling (as indicated by mitral regurgitation scores, left atrial-to-aortic root diameter ratios, and fractional shortening values). Durations of anesthesia and surgery were also significantly longer for CDO implantation versus SL. The major complication rate for dogs treated by SL (6/62 [10%]) was significantly greater than that for dogs treated by CDO implantation (0/58 [0%]). One dog in the SL group died during surgery. Overall rate of survival to hospital discharge was 99% (119/120). CONCLUSIONS AND CLINICAL RELEVANCE Both SL and CDO implantation were viable methods for PDA attenuation in the evaluated dogs. Although a greater proportion of dogs had major complications during the SL procedure, the 2 procedures had comparable rates of survival to hospital discharge.

Relationship between Device Size and Body Weight in Dogs with Patent Ductus Arteriosus Undergoing Amplatz Canine Duct Occluder Deployment.

BackgroundDeployment of the Amplatz Canine Duct Occluder (ACDO) is the preferred method for minimally invasive occlusion of patent ductus arteriosus (PDA) in dogs, with appropriate device sizing crucial to successful closure. Dogs of any body weight can be affected by PDA.ObjectivesTo describe the range of ACDO sizes deployed in dogs of various body weights for improved procedural planning and inventory selection and to investigate for correlation between minimal ductal diameter (MDD) and body weight.AnimalsA total of 152 dogs undergoing ACDO deployment between 2008 and 2016.MethodsBody weight, age, breed, sex, and MDD obtained by angiography (MDD‐A), MDD obtained by transesophageal echocardiography (MDD‐TEE), and ACDO size deployed were retrospectively evaluated.ResultsCorrelation between body weight and ACDO size, MDD‐A and MDD‐TEE was poor, with R‐squared values of 0.4, 0.36, and 0.3, respectively. Femoral artery diameter in the smallest population of dogs placed inherent limitations on the use of larger device sizes, with no limitations on the wide range of device sizes required as patient size increased. The most commonly used ACDO devices were size 3 through 6, representing 57% of the devices deployed within the entire study population.Conclusions and Clinical ImportancePatent ductus arteriosus anatomy varies on an individual basis, with poor correlation between MDD and body weight. Weight‐based assumptions about expected ACDO device size for a given patient are not recommended.

Prolonged reflex bradycardia after occlusion of patent ductus arteriosus with an Amplatz canine duct occluder in a dog

Prolonged reflex bradycardia after occlusion of patent ductus arteriosus with an Amplatz canine duct occluder in a dog

Closure of Patent Ductus Arteriosus in a Maltese Dog Using Amplatz Canine Duct Occluder through Femoral Vein

Closure of Patent Ductus Arteriosus in a Maltese Dog Using Amplatz Canine Duct Occluder through Femoral Vein

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.

Transesophageal echocardiography as the sole guidance for occlusion of patent ductus arteriosus using a canine ductal occluder in dogs.

BackgroundTranscatheter occlusion of patent ductus arteriosus (PDA) is usually performed by fluoroscopy alone or together with transesophageal echocardiography (TEE). Transthoracic echocardiography (TTE) guidance has been used for deployment of Amplatz Canine Ductal Occluder (ACDO), but sometimes is limited by suboptimal acoustic windows. Transesophageal echocardiography can overcome such issues and provides higher image resolution at the level of the great vessels.ObjectivesTo determine if TEE without fluoroscopy could be used to successfully perform ductal occlusion for the treatment of PDA in dogs.AnimalsTwenty client‐owned dogs with PDA.MethodsA prospective consecutive case series of PDA occlusion was performed using only TEE guidance. Dogs were positioned in right lateral recumbency and the TEE probe was positioned to visualize the descending aorta, PDA, and pulmonary artery. The guide wire, long introducer sheath, and ACDO were imaged by TEE to direct deployment.ResultsDuctal occlusion was performed successfully without need for fluoroscopy and without complications in 19 dogs. One dog required a second larger ACDO because of embolization of the first device 18 hours after positioning.Conclusions and Clinical ImportanceWe have demonstrated that TEE monitoring without concurrent fluoroscopy can guide each step of transcatheter ACDO embolization thereby providing an alternate method of visualization for this procedure. Use of TEE alone can reduce radiation exposure or is an option when fluoroscopy is not available, and, therefore, should be evaluated in a larger case series to better assess procedural failure rates.

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.

Transthoracic echocardiographically-guided interventional cardiac procedures in the dog

ObjectivesInterventional cardiac procedures are traditionally performed using fluoroscopy, or, more recently, transesophageal echocardiography (TEE). Neither modality is widely available to practicing cardiologists worldwide. We examined whether balloon valvuloplasty of pulmonic stenosis (PS) and transarterial occlusion of patent ductus arteriosus (PDA) in dogs could be performed safely with transthoracic echocardiography (TTE). AnimalsA prospective consecutive case series of 26 client-owned dogs with PS (n = 10) and PDA (n = 16). MethodsThe cardiovascular procedures were performed using TTE. Each dog was positioned on a standard echocardiography table in right lateral recumbency (dogs with PS) or left lateral recumbency (dogs with PDA). Guide wires, balloon catheters, Amplatz® Canine Ductal Occluder (ACDO) delivery sheaths, and ACDO were imaged by standard echocardiographic views optimized to allow visualization of the defects and devices. ResultsProcedures were performed successfully without major complications in 20 dogs. In 2 dogs (German shepherds) with Type III PDA, ACDO placement was unsuccessful; 2 other German Shepherds were excluded from the procedure because their ductal diameters, measured echocardiographically, exceeded the limits of the maximal ACDO size. Two dogs weighing ≤3.5 kg had suboptimal echocardiographic visualization of the PDA and were considered too small for safe ACDO deployment. All intravascular devices at the level of the heart and great vessels appeared hyperechoic on TTE image and could be clearly monitored and guided in real-time. ConclusionsWe have demonstrated that TTE monitoring can guide each step of pulmonic balloon valvuloplasty and PDA occlusion without fluoroscopy.