Percutaneous Atrial Septal Defect Occlusion Using the Amplatzer® Septal Occluder in 9 Dogs: Short and Mid-Term Outcome
The Michael E. DeBakey Institute, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University
College Station, TX, USA
Percutaneous atrial septal defect (ASD) occlusion in the dog was first reported by Sanders et al in 2005. Herein we report the results of Amplatzer® septal occluder deployment in 10 dogs with ASD seen between 01/11/05 and 01/10/07. Breeds included Standard poodle (7/10), Boxer (2/10) and Dalmatian. All dogs were female with a mean age of 3.9 ± 2.4 (mean ± SD), weighing 21 ± 3.5 kg. All dogs had isolated left to right shunting septum secundum ASD. Six dogs had left base systolic heart murmurs ranging in grade from I-IV/VI. All dogs had echocardiographic evidence of moderate (4/10) to severe (6/10) right atrial and ventricular enlargement. Four of 6 dogs had evidence of pulmonary hypertension (PH) with Doppler estimated systolic pulmonary artery pressures of 60 ± 28 mmHg. Eight dogs had no clinical signs, 1 dog had exercise intolerance and 1 dog had congestive heart failure.
All devices were deployed via a right jugular approach. The femoral vein approach was attempted in the initial dog but was unsuccessful. This dog was subsequently occluded from the right jugular. Transthoracic echocardiographic estimates of ASD size were 12.7 ± 5.4 mm with a range of 7-22 mm. Device size selection was based on the stop flow balloon inflation estimate of ASD size. Devices were successfully deployed in 9 of 10 dogs. One dog had inadequate ASD rim tissue which precluded occlusion. This dog was subsequently recovered and offered open heart repair which the owners declined. Deployed Amplatzer® septal occluder size was 16.4 ± 3.4 mm with a range of 12-22 mm. Median fluoroscopy time was 17.5 minutes with an interquartile range of 9-33 minutes and absolute range of 7-112 minutes. Transthoracic color Doppler echocardiography performed the day following the procedure revealed complete occlusion in 4 of 9 dogs, trivial to mild residual flow in 4 of 9 dogs and moderate residual flow in one dog. Follow-up echocardiograms (6.0 ± 4.0 months after the procedure) were available for 7 of 9 dogs. Right atrial and ventricular enlargement resolved in 3 of 7 and reduced to mild in the remaining 4 of 7 dogs. PH resolved in all 4 dogs in which it was documented prior to device deployment. Severity of residual ASD flow was unchanged and judged to be hemodynamically insignificant. The only complication was inadvertent device deployment into the right ventricle in 1 dog requiring catheter based retrieval. Following device retrieval this dog was successfully occluded. All dogs were discharged on aspirin 1.3 ± 0.6 mg/kg PO q 24 hrs for 6 months. The total mean follow-up time in these 9 dogs is 14.2 ± 9.1 months. Clinical signs resolved in the two symptomatic dogs and no dog has had mid-term complications.