Detachable Coils for Occlusion of Patent Ductus Arteriosus in 2 Dogs

OBJECTIVE: To describe the use of a detachable coil for transcatheter closure (TCC) of patent ductus arteriosus (PDA) in 2 dogs. STUDY DESIGN: Clinical study. ANIMALS: Two female Pembroke Welsh Corgi dogs with PDA. METHODS: Using fluoroscopic guidance, an 8-mm-diameter coil stent with 5 loops (detachable coils for PDA closure) was inserted via catheterization of the femoral artery. The catheter was passed through the PDA into the pulmonary artery. The coil was withdrawn so that 1.5 loops remained on the pulmonary side of the orifice of the ductus. The rest of the loops were pushed out from the catheter into the ductus. After confirming the correct placement of the coil and the effectiveness of the occlusion, the delivery wire was detached from the coil. RESULTS: Insertion of the coil was easily performed, even without previous experience. Immediate and marked decrease of the cardiac murmur was auscultated. Only slight residual flow was detected by angiography conducted 3 months' postoperatively. The dogs experienced quick and uneventful recovery after coil placement and required minimal postoperative care. Follow-up evaluation of the dogs showed no functional clinical signs of PDA, and no cardiac abnormalities were detected on electrocardiographic, phonocardiographic, and echocardiographic examination. In dog 1, the residual flow had disappeared on the color-flow Doppler echocardiographic examination at 18 months' postoperatively. CONCLUSION: TCC using a detachable coil was easy, safe, and effective in 2 dogs with PDA. The minimal residual shunting observed only by echocardiography seemed hemodynamically insignificant. CLINICAL RELEVANCE: This method can be used as an alternative to traditional surgical methods.     

Transthoracic echocardiographic measurement of patent ductus arteriosus in dogs

BACKGROUND: Patent ductus arteriosus (PDA) size and morphology influence the selection of the kind and the size of the embolization device used to effect shunt closure. HYPOTHESIS: That echocardiographic measurement of PDA in dogs is accurate. ANIMALS: Forty-five client-owned dogs with PDA. METHODS: Prospective observational study. Echocardiographic and angiographic data were compared. RESULTS: Measurement of the ductus in color Doppler echocardiography (CD-E) and 2-dimensional echocardiography (2D-E) was achieved from left parasternal views in 43 of 45 unsedated dogs (96%). In these 43 dogs, the angiographic minimal PDA diameter was 3.72 +/- 1.59 mm, and the diameter of the PDA ampulla was 8.46 +/- 3.01 mm. The CD-E minimal PDA diameter ranged from 2.3 to 9.5 mm (median, 4.0 mm). There was a significant mean difference to the angiographic measurements (1.15 +/- 0.95 mm; P < .0001). An agreement in a 1-mm range was found in 21 of 43 dogs (48%). The 2D-E minimal PDA diameter was 3.73 +/- 1.78 mm, and the mean difference to the angiographic measurements was not significant (0.00 +/- 0.72 mm; P = .98). An agreement in a 1-mm range was found in 31 of 43 dogs (72%). The 2D-E measurement of the PDA ampulla revealed a significant mean difference to the angiographic data (1.95 +/- 2.43 mm, P < .0001). An agreement in a 2-mm range was found in 21 of 43 dogs (49%). CONCLUSIONS AND CLINICAL IMPORTANCE: The 2D-E from the left cranial parasternal view is an excellent noninvasive method to estimate the PDA minimal diameter before doing catheter intervention.     

Coil occlusion of residual shunts after surgical closure of patent ductus arteriosus

OBJECTIVE; To describe use of coil embolization to occlude residual flow through a patent ductus arteriosus (PDA) after incomplete surgical ligation. STUDY DESIGN: Clinical study. ANIMALS: Dogs (n=4) with continuous murmur after surgical ligation of PDA. METHODS: After PDA ligation, residual ductal flow through the PDA was visible on color-flow Doppler examination and left ventricular end-diastolic diameter remained increased. Coil embolization by an arterial approach was performed to achieve complete occlusion of the PDA. RESULTS: Embolization coils were delivered without complications and hemodynamically successful occlusion was achieved. Doppler-visible flow resolved in 2 dogs within 3 months after embolization. Left ventricular end-diastolic diameter indexed to body weight decreased in all dogs. CONCLUSIONS: Transcatheter coil embolization appears to be a safe and minimally invasive procedure for complete occlusion of residual PDA flow after incomplete surgical ligation. CLINICAL RELEVANCE: Transcatheter coil embolization should be considered for correction of hemodynamically significant residual shunts in dogs that have incomplete PDA occlusion after open surgical ligation.     

Coil embolization of patent ductus arteriosus via the carotid artery in seven dogs

This study was designed to evaluate the feasibility and limitations of transcatheter embolization coil occlusion of patent ductus arteriosus in dogs using a carotid artery approach. Seven dogs examined at the University of California, Davis Veterinary Medical Teaching Hospital in 2002-2003 for evaluation of heart disease had congenital patent ductus arteriosus diagnosed by characteristic physical, electrocardiographic, radiographic, and anatomic and Doppler echocardiographic findings. Dogs were anesthetized for transesophageal echocardiography and transcatheter coil embolization of the ductus via the right external carotid artery. Coil embolization was achieved in all seven cases, using one to four detachable embolization coils. There were no major complications. Minor complications occurred in two dogs (additional coils placed using a femoral arterial approach and coil embolization of a left femoral artery branch). One dog was examined only 24 h post-operatively and had no murmur and trivial residual ductal flow by Doppler echocardiography. The other 6 dogs were clinically healthy when examined up to three years post-intervention. One dog had a very soft continuous murmur and mild residual ductal flow; the other five had no audible continuous murmur, with only one dog having trivial residual ductal flow identified by Doppler echocardiography. Although technically challenging, coil embolization via the carotid artery is a viable alternative approach for transcatheter closure of patent ductus arteriosus in some dogs.     

Transcatheter closure of patent ductus arteriosus using occluding spring coils

The purpose of this study is to report our initial experience with the use of spring coils to close the patent ductus arteriosus in the dog. There are few large-patient series reported in the veterinary literature. Coil closure was attempted in 15 dogs (median weight, 6.5 kg; range, 1.2 to 38.7 kg) presenting with a patent ductus arteriosus between May 1997 and May 1999. Arterial catheterization followed by angiography was used to decide if coil placement was adequate. A 5- or 8-mm embolization coil, depending on the angiographic diameter of the ductus, was delivered, with 1 loop in the pulmonary arterial side and the remainder of the coil in the aortic side of the duct. Additional coils were used if a residual shunt was present, and closure was confirmed by aortography. Patients were discharged the day after the procedure. Successful coil closure, without residual shunt on angiography, was achieved in 11 of 13 dogs in which coils were released. In 6 dogs, a coil embolized to the pulmonary artery. Four of these dogs had successful closure with multiple coils, and 2 others had surgery. None of these dogs experienced adverse effects. In 2 dogs with conical patent ductus arteriosus >5 mm in minimal diameter, coil closure was not done. We conclude that the patent ductus arteriosus size and anatomical shape are crucial in deciding whether coil closure is the method of choice. In selected cases, coil closure represents an elegant alternative to surgical ligation. Although pulmonary embolism occurred commonly, it did not cause any obvious clinical problem.     

Long-term follow-up after transvenous single coil embolization of patent ductus arteriosus in dogs

Background: Long‐term follow‐up studies after interventional therapy of patent ductus arteriosus (PDA) in dogs are rare. Hypothesis: Transvenous PDA embolization with a single detachable coil is a highly effective method in patients with an angiographically determined PDA ≤ 4.0 mm. Animals: Twenty‐eight dogs with an angiographic PDA ≤ 4.0 mm were included. Methods: Prospective follow‐up study after PDA coil embolization. Results: The median follow‐up time was 792 days (range, 2–3, 248 days). The rate of complete closure demonstrated by Doppler color flow was 54% at day 3 after intervention and the final cumulative rate was 71%. The rate of complete closure was significantly different between small and moderately sized PDA over the study period (P < .0001) and finally was 100 and 50%, respectively. In 16 dogs with complete closure, no recanalization was found. Disappearance of the continuous heart murmur was found in 89% after 3 days, and this increased to a final cumulative rate of 96%. Indexed left ventricular internal diameter in diastole (LVDd‐I) decreased significantly (P < .0001). In the group with moderately sized PDA, a significant difference (P= .0256) was seen in LVDd‐I between patients with and without residual shunt after exclusion of patients with persistent severe mitral valve regurgitation. Conclusion and Clinical Importance: Long‐term follow‐up after single coil embolization showed complete closure in all small PDA but a residual shunt with mild hemodynamic consequences was present in half of the moderately sized PDA.     

Transvenous coil embolization of patent ductus arteriosus in small (≤3.0 kg) dogs

Background: Surgical and interventional therapy for occlusion of a patent ductus arteriosus (PDA) in small dogs is challenging. Interventional closure of a PDA is rarely described in small dogs. Hypothesis: Transvenous single‐coil occlusion of a PDA in small (≤3.0 kg) dogs is possible and safe. Animals: Twenty‐one client‐owned dogs with a left‐to‐right shunting PDA. Methods: Prospective clinical study. Inclusion criteria were a left‐to‐right shunting PDA and a body weight ≤3.0 kg. Dogs with additional congenital cardiac diseases were excluded. Without arterial access, a single detachable coil was implanted by a transvenous approach with a 4 Fr catheter. Results: Twenty‐one dogs were the study population with Chihuahua and Yorkshire Terrier being the commonest breeds (n = 6 and n = 5, respectively). There were 14 female and 7 male dogs. The age range was 1.9–83.5 months (median, 7.7 months), and the body weight was 1.0–2.9 kg (1.87 ± 0.45). By angiography, the minimal ductal diameter measured 1.2–2.4 mm (median, 1.8 mm) and the PDA ampulla diameter was 2.4–5.9 mm (median, 4.6 mm). Coil implantation was successful in all dogs. After detachment of the coil from the delivery cable, repositioning of the pulmonary loop of the coil became necessary in 1 dog. The prevalence of immediate closure was 76%. The prevalence of cumulative closure was 90%. Conclusion: For an experienced cardiologist, transvenous occlusion of a PDA in small dogs is possible with a 4 Fr catheter and a commercial single detachable coil. Arterial access is not essential. The procedure is safe and successful in experienced hands.     

Transarterial coil embolization of patent ductus arteriosus in small dogs with 0.025-inch vascular occlusion coils: 10 cases

Patent ductus arteriosus (PDA) is the most common congenital cardiac disease in the dog and generally leads to severe clinical signs, including left-sided congestive heart failure. Historically, definitive treatment consisted of surgical ligation; however, the use of vascular occlusion devices by minimally invasive techniques has gained popularity in veterinary medicine during the past decade. Adequate vascular access is a major limiting factor for these minimally invasive techniques, precluding their use in very small dogs. The clinical management of PDA with 0.025-in vascular occlusion coils in a minimally invasive transarterial technique in 10 dogs is described. The dogs were small (1.38 +/- 0.22 kg), were generally young (6.70 +/- 5.74 months), and had small minimal ductal diameters (1.72 +/- 0.81 mm from angiography). Vascular access was achieved, and coil deployment was attempted in all dogs with a 3F catheter uncontrolled release system. Successful occlusion, defined as no angiographic residual flow, was accomplished in 8 of 10 (80%) dogs. Successful occlusion was not achieved in 2 dogs (20%), and both dogs experienced embolization of coils into the pulmonary arterial tree. One of these dogs died during the procedure, whereas the other dog underwent a successful surgical correction. We conclude that transarterial PDA occlusion in very small dogs is possible with 0.025-in vascular occlusion coils by means of a 3F catheter system and that it represents a viable alternative to surgical ligation. The risk of pulmonary arterial embolization is higher with this uncontrolled release system, but this risk may decrease with experience.     

Closure of a persistent ductus arteriosus of Botallo in two dogs using transarterial coil embolization

Non-surgical occlusion of persistent ductus arteriosus (PDA) by catheter guided coil embolisation was performed in two dogs. In both dogs the procedure was performed through the femoral artery. The exact location and the narrowest diameter of the PDA were evaluated angiographically after contrast medium injection into the ascending aorta. Based on shunt diameter measurements of 4 mm in dog no. 1 and 2.4 mm in dog no. 2, a coil of 8 mm diameter was chosen for dog no. 1, and of 5 mm diameter for dog no. 2. The coils were placed within the shunt vessel under fluoroscopic guidance using the Cook delivery-system for detachable PDA coil. The success of the intervention was documented angiographically 10 minutes after coil release. The shunt vessel was completely occluded in dog no. 1, while minimal blood flow was detected in dog no. 2 at that time. The technique of transvascular PDA closure compares favorably with the traditional surgical technique due to minimal invasiveness and hence excellent postinterventional comfort to the patient.     

Catheter closure of patent ductus arteriosus in dogs: variation in ductal size requires different techniques

Background:Catheter closure of patent ductus arteriosus Botalli (PDA) is increasingly replacing traditional surgical ligation via thoracotomy. A variety of techniques have been described in dogs, although the technique and implant chosen may depend on the minimum ductus diameter.Objectives:To evaluate the feasibility and treatment of choice of catheter closure of large and small PDAs in dogs.Methods:In 16 dogs with a PDA, catheter closure was performed using transarterial embolisation using detachable or free coils, or transvenously using an Amplatzer, duct occluder (ADO).Results:In 8 dogs, closure of PDA with a minimum diameter of < 4 mm was achieved using detachable coils; 2 or more coils were required in 3 dogs. In 5 dogs with minimum ductus diameters of > 4 mm, detachable coils were not applicable. In one of these dogs, (incomplete) surgical ligation was performed and later a free coil placed for complete closure. In 2 dogs with moderately large PDA (5 mm), several free coils were implanted. Complete closure was not achieved in either dog and transient haemolysis occurred as a complication. In 2 dogs with a very large PDA (6 mm), implanted free coils embolised to pulmonary arteries and closure was then achieved using an ADO. In 3 dogs with an excessively large PDA (7.5-10 mm) closure was successfully achieved using an ADO with no complications.Conclusions:Coil embolisation is readily feasible for closure of PDA < 4 mm, less feasible for PDA < 5 mm and unlikely to be feasible to close PDA > 5 mm. Detachable coils are safe for PDA < 4 mm, and the ADO is an excellent device for PDA > 5 mm.     

Pulmonary embolization of vascular occlusion coils in dogs with patent ductus arteriosus

Transcatheter coil embolization of patent ductus arteriosus (PDA) was performed in 206 dogs between 1994 and 2003 at Texas A&M University, of which 7 (3%) had embolization of coils to the pulmonary vasculature. Thoracic radiographs indicated that coils were located in the right pulmonary artery in 6 of the 7 dogs. Pulmonary perfusion scans were available for review in 5 dogs, and moderate perfusion defects were observed in the right caudal lung lobe in 4 dogs within 24 hours of embolization. Perfusion deficits observed initially in 2 of the dogs resolved on perfusion scans performed at 6 months and 3.1 years. One dog did not have evidence of focal perfusion defects on a perfusion scan performed 4.5 months after embolization. All pulmonary embolizations occurred during the procedure. Attempts at retrieval of coils were unsuccessful in the 2 dogs in which it was attempted. No short- or long-term clinical complications were observed in any of the dogs with pulmonary embolization. We conclude that pulmonary embolization of vascular occlusion coils is an uncommon event and is not typically associated with adverse clinical effects in dogs with PDA.     

Transvenous detachable coiling of patent ductus arteriosus in small dogs

ObjectiveTo report on transvenous detachable coiling in small dogs deemed ineligible for traditional transarterial patent ductus arteriosus occlusion and compare transthoracic echocardiographic and angiographic measurements to determine their equivalence.Materials and methodsA retrospective study of 35 dogs that underwent transvenous coiling of a patent ductus arteriosus. Demographic information, echocardiographic and angiographic studies, surgery reports, and follow-up evaluation of residual flow were obtained. A Bland-Altman analysis was used to compare echocardiographic and angiographic measurements of the minimal ductal diameter (Echo-MDD, Ang-MDD) and ampulla diameter (Echo-A, Ang-A).ResultsThirty-four of 35 dogs had successful deployment of a coil, with one dog undergoing occlusion with a different device after the exteriorized coil pulled through the ductus. Complete occlusion was achieved in 18 dogs within 24 h; four dogs were lost to follow-up, and the remaining 12 dogs had no residual flow or a significant reduction in shunting with normalization in cardiac chamber dimensions by a median of 99 days. Thirty percent of dogs (11/35) experienced perioperative complications of which 10 were minor complications. The analysis of 26 dogs with both echocardiographic and angiographic ductal measurements showed a −0.14 mm mean difference (95% limits of agreement −1.08 to 0.8 mm) in minimal ductal diameter and −0.68 mm mean difference (95% limits of agreement −2.73 to 1.37 mm) in ampulla diameter.ConclusionsDogs less than 3 kg deemed too small for transarterial occlusion can successfully undergo transvenous coil embolization of patent ductus arteriosus.     

Transcatheter closure of congenital ventricular septal defects in 3 dogs with a detachable coil

The purpose of this study was to evaluate the feasibility, safety, and efficacy of transcatheter closure in dogs with a congenital perimembranous ventricular septal defect (VSD) by using a detachable coil. No dogs showed any symptoms, and results of chest X-rays and ECGs were normal. The diameters of VSD ranged from 2 to 4 mm on echocardiogram. The defect was 2-2.5 mm from the aortic valve. A detachable coil (size 5 mm with 5 loops) designed for patent ductus arteriosus was delivered via the transarterial route. The device was successfully employed in all dogs. A minimal residual shunt was observed in all dogs even though Qp/Qs decreased. Hemolysis and a rate-dependent right-bundle branch block were observed in 1 dog, but there was no clinical significance. No major complication was noted. Pathologic examination after 1 year revealed that the coils were covered with tissue without significant damage to the His-Purkinje conduction system. In conclusion, transcatheter closure of a small perimembranous VSD with a detachable coil can be achieved without major complications or significant pathologic damage at the lesion site.     

Treatment of patent ductus arteriosus by placement of two intravascular embolisation coils in a puppy

A 14-week-old border collie with a history of exercise intolerance was confirmed to have a patent ductus arteriosus (PDA) from colour flow Doppler echocardiography. Under general anaesthesia, angiography was performed to gauge accurately the width of the ductus, and then two intravascular embolisation coils were introduced into the ductus via percutaneous catheterisation of the femoral vein. The coils were both 8 mm in diameter, each with four loops. This led to an immediate disappearance of the murmur. Some slight residual flow was detected at the time of the procedure by angiography, but by 10 days postoperatively there was no PDA flow detectable. The time taken to complete the procedure was 55 minutes, with a total fluoroscopy time of 15 minutes. Placement of intravascular embolisation coils represents a viable alternative to traditional surgical methods of ductus closure.     

Transarterial ductal occlusion with the Amplatzer vascular plug in 31 dogs

Background: Transarterial ductal occlusion with the Amplatzer vascular plug was first reported in dogs by Hogan et al in 2005. Hypothesis: Use of the Amplatzer vascular plug is a safe, efficacious method of patent ductus arteriosus (PDA) occlusion. Animals: Thirty‐one client‐owned dogs with PDA. Methods: Records of 31 dogs in which transarterial occlusion of PDA with an Amplatzer vascular plug was attempted were reviewed. Results: All dogs had a type II PDA, with 27 dogs having type IIA morphology and 4 dogs having type IIB morphology. Appropriate device deployment was achieved in 29 of 31 dogs. Postdeployment angiography in 21 dogs documented complete occlusion in 10 dogs, trivial residual flow in 5 dogs, mild residual flow in 2 dogs, moderate residual flow in 3 dogs, and severe residual flow in 1 dog. Transthoracic color Doppler echocardiography documented complete occlusion in 22 dogs, whereas 2 dogs had trivial residual flow, 2 dogs had mild residual flow, 2 dogs had mild to moderate residual flow, and 1 dog had severe residual flow. Of the 7 dogs with residual flow, 2 had complete occlusion 2–4 months postoperatively, 1 had moderate residual flow 1 month postoperatively, and 4 were lost to follow‐up. One dog required a larger device than was able to be deployed through the largest sheath placed in the femoral artery. Pulmonary embolization of the device occurred in 1 dog. Conclusion: We conclude that ductal occlusion with an Amplatzer vascular plug is a safe and efficacious therapy for PDA in dogs.     

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 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.     

Evaluation of the efficacy and safety of coil occlusion for patent ductus arteriosus in dogs

We performed a retrospective study of 56 dogs with Patent Ductus Arteriosus (PDA) to evaluate the indications for and efficacy of transarterial PDA coil embolization. Transarterial PDA coil embolization was conducted in 37 cases (66.1%) and surgical ligation was conducted in 16 cases (28.6%). Three cases (5.4%) were diagnosed as pulmonary hypertension and were excluded from surgical intervention. Although coil dislodgement was observed in the pulmonary artery in one case, no death occurred during coil embolization or surgical ligation. Echocardiography showed that fractional shortening decreased from 35.4 +/- 6.8% to 30.2 +/- 5.9% (P<0.05) after transarterial PDA coil embolization. Although slight residual shunts were observed in 18 cases, transarterial PDA coil embolization was effective treatment of PDA.     

Echocardiographic and angiographic comparison of ductal dimensions in dogs with patent ductus arteriosus

BACKGROUND: Transcatheter occlusion of patent ductus arteriosus (PDA) is a minimally invasive treatment option in dogs. Device selection based on appropriately acquired PDA dimensions and morphology can minimize procedural complications, including minimizing residual ductal flow and inappropriate embolization. HYPOTHESIS: Transesophageal echocardiographic (TEE) derived minimum ductal diameter measurements would most accurately reflect angiographic measurements. Color Doppler (CD) TEE and transthoracic echocardiographic (TTE) ductal measurements would overestimate two-dimensional (2D) measurements. ANIMALS: Fifteen client-owned dogs with PDA. METHODS: PDA dimensions obtained with angiography, 2D and CD TTE, 2D and CD TEE from the right and left views were prospectively evaluated. RESULTS: PDA dimensions were measured by using TEE most closely approximated angiographic measures. CD TTE and TEE frequently overestimated angiographic measures of minimum ductal diameter. TEE accurately identified a type III (tubular) PDA morphology in 1 dog. Fourteen of 15 dogs were determined to have hemodynamically significant reductions in left to right shunting documented by a first-pass nuclear angiocardiographic ratio of pulmonary to systemic blood flow < or = 1.2 and trivial (n = 3) to no (n = 11) CD TTE flow at approximately 1 month after PDA occlusion. CONCLUSIONS: TEE provided accurate anatomic information regarding PDA morphology and closely approximated angiographic ductal dimensions while aiding in both coil deployment and confirmation of intra-operative ductal closure.