Open heart closure of an atrial septal defect by use of an atrial septal occluder in a dog

Sonya G. Gordon Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.
Michael E. DeBakey Institute for Comparative Cardiovascular Sciences and Biomedical Devices, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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David A. Nelson Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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Sarah E. Achen Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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Matthew M. Miller Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.
Michael E. DeBakey Institute for Comparative Cardiovascular Sciences and Biomedical Devices, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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Risa M. Roland Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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Ashley B. Saunders Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.
Michael E. DeBakey Institute for Comparative Cardiovascular Sciences and Biomedical Devices, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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Lori T. Drourr Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4474.

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Abstract

Case Description—A 3-year-old sexually intact male Standard Poodle was admitted to the veterinary teaching hospital for transcatheter closure of a large atrial septal defect (ASD).

Clinical Findings—The dog had exercise intolerance and was thin. Findings on physical examination were within normal limits with the exception of a left base systolic heart murmur (grade 5/6). The dog was not receiving any medications. Echocardiography and thoracic radiography confirmed the diagnosis of ASD and revealed compensatory changes consistent with a large left to right shunting ASD. Results of serum biochemical analysis and CBC were within reference range limits.

Treatment and Outcome—Transcatheter ASD closure with an atrial septal occluder (ASO) was performed and failed. An open heart surgical approach under cardiopulmonary bypass was declined by the dog's owners. The dog underwent a novel hybrid approach involving active device fixation under temporary inflow occlusion after transatrial device deployment. The dog recovered with some manageable postoperative complications. As of the last follow-up examination, the dog had 10 months of event-free survival.

Clinical Relevance—Transcatheter closure by use of an ASO and open heart patch repair with cardiopulmonary bypass to surgically treat dogs with ASD has been reported. Transcatheter closure is not possible in dogs with large ASD. The novel hybrid procedure reported herein represented a viable alternative to euthanasia.

Abstract

Case Description—A 3-year-old sexually intact male Standard Poodle was admitted to the veterinary teaching hospital for transcatheter closure of a large atrial septal defect (ASD).

Clinical Findings—The dog had exercise intolerance and was thin. Findings on physical examination were within normal limits with the exception of a left base systolic heart murmur (grade 5/6). The dog was not receiving any medications. Echocardiography and thoracic radiography confirmed the diagnosis of ASD and revealed compensatory changes consistent with a large left to right shunting ASD. Results of serum biochemical analysis and CBC were within reference range limits.

Treatment and Outcome—Transcatheter ASD closure with an atrial septal occluder (ASO) was performed and failed. An open heart surgical approach under cardiopulmonary bypass was declined by the dog's owners. The dog underwent a novel hybrid approach involving active device fixation under temporary inflow occlusion after transatrial device deployment. The dog recovered with some manageable postoperative complications. As of the last follow-up examination, the dog had 10 months of event-free survival.

Clinical Relevance—Transcatheter closure by use of an ASO and open heart patch repair with cardiopulmonary bypass to surgically treat dogs with ASD has been reported. Transcatheter closure is not possible in dogs with large ASD. The novel hybrid procedure reported herein represented a viable alternative to euthanasia.

A 3-year-old sexually intact male (22.4-kg [49.4-lb]) Standard Poodle was admitted to the Texas A&M University Veterinary Teaching Hospital for transcatheter closure of a large ASD. The dog was observed to have exercise intolerance and was thin with a body condition score of 2.5 (9-point scale, with 1 indicating emaciation and 9 indicating severe obesity). Findings on physical examination were within normal limits with the exception of a left base systolic heart murmur (grade 5/6). The dog was not receiving any medications. On TTE (Figure 1), a large ASD (21.4 mm in diameter as measured from a TTE image) was evident that was resulting in severe compensatory right atrial and right ventricular dilation and moderate pulmonary hypertension. The estimated right atrial to right ventricular pressure gradient was 86 mm Hg. Thoracic radiography revealed modest generalized cardiomegaly with accentuation of the right atrium and ventricle and pulmonary trunk (Figure 2). The peripheral pulmonary blood vessels were mildly accentuated, consistent with pulmonary overcirculation secondary to a left to right shunt. As an incidental finding, there were multiple metallic objects in the craniodorsal area of the abdomen on the left side presumed to be vascular clips from a previous surgery for gastric dilatation and volvulus. Findings on serum biochemical analysis and CBC were within reference range limits.

Figure 1—
Figure 1—

Right parasternal 4-chamber TTE image. Right atrial and ventricular dilation with a large (arrow) ASD is evident. LA = Left atrium. LV = Left ventricle. RA = Right atrium. RV = Right ventricle.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

Figure 2—
Figure 2—

Preoperative right lateral (A) and ventrodorsal (B) radiographic views of the thorax. Notice the moderate generalized cardiomegaly with accentuation of the right atrium and ventricle and of the pulmonary trunk. The peripheral pulmonary blood vessels are mildly accentuated consistent with overcirculation associated with a left to right shunt. As an incidental finding, there are multiple metallic objects in the left craniodorsal portion of the abdomen presumed to be vascular clips.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

General anesthesia was induced by use of a standardized protocol that included premedication with hydromorphone and glycopyrrolate followed by induction with diazepam and etomidate. Balanced anesthesia was maintained with a constant rate infusion of fentanyl and midazolam along with inhalation of sevoflurane. Perioperatively, the dog also received cefazolin, procainamide (15 mg/kg [6.8 mg/lb], IM, once, then as needed via IV bolus), lidocaine (2 mg/kg [0.9 mg/lb], IV, once, then at a constant rate infusion of 50 μg/kg/min [22.7 μg/lb/min] with the bolus repeated as needed), and heparin (100 U/kg [45.5 U/lb], IV).

The right jugular vein was approached percutaneously via the Seldinger technique.1 A 12-F sheath introducera was placed within the jugular vein. Introducer size was determined on the basis of the expected delivery sheath size, which in turn was determined on the basis of the expected ASO size estimated from preoperative TTE and TEE measurements. The commercially available delivery sheath packageb was complete, with everything needed to load and deploy the ASO.b

Transesophageal echocardiography was performed throughout the interventional catheterization procedure to further characterize ASD size and morphology. The use of TEE was also crucial for ASO deployment, confirmation of secure deployment prior to release, assessment of ASD closure after release, and positioning catheters, in particular while gaining access to the left atrium. Concurrent fluoroscopic imaging was performed as needed to pass appropriate catheters, deploy the ASO, and release the ASO. To confirm secure ASO deployment prior to device release, TTE was used. Following determination of a secure ASO position, the device was released. While preparing to close the catheterization site, intermittent TEE was continued and, within 10 minutes of release, revealed device embolization into the right atrium. The device was captured with a snare catheter but was too large to be successfully removed via a catheter-based system, and an emergency thoracotomy was performed.

A right-side fourth intercostal thoracotomy was performed. The pericardium dorsal to the right phrenic nerve was incised and the right atrium exposed. The occlusion device could readily be palpated through the wall of the right atrium. A purse-string suture was placed in the mid portion of the right atrium (4-0 polypropylene). A second purse-string suture was placed just outside the circumference of the first as a safety measure in the event the first suture failed. Both pursestring sutures were secured with Rumel tourniquets. A 32-F straight thoracic catheterc was shortened to a length of 17 cm, with a bevel cut in 1 end. With the tube occluded by a preplaced tubing clamp, the tube was inserted via a stab incision through the purse-string suture and into the right atrium (Figure 3). Because right atrial pressures were too low to force blood all the way up and out of the catheter, it was possible to remove the clamp and insert long alligator forceps into the atrial chamber. The occlusion device was palpated through the atrial wall and positioned below the modified chest tube, where it could be blindly grasped in the alligator forceps. The device was then deformed by traction and extracted through the catheter while slack was provided on the existing snare. The purse-string suture was then closed as the catheter was removed from the atrium. The second purse-string suture was also tied. The pericardial sac was left unsutured and the thoracic cavity closed in routine fashion. The total anesthesia time for both procedures combined was 6 hours 15 minutes. Recovery from anesthesia was uncomplicated.

Figure 3—
Figure 3—

Intraoperative photograph of the modified thoracic catheter secured in the right atrium.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

Following unsuccessful transcatheter closure, an open heart patch repair under cardiopulmonary bypass was discussed with and declined by the owner. However, a modified open heart procedure was elected and scheduled for 7 days after the first procedure.

General anesthesia was as described previously with some modifications. Active surface cooling to a target core body temperature between 32° and 34°C (89.6° and 93.2°F) was initiated immediately after induction, and dobutamine was administered as needed to support systemic blood pressure. The incision from the prior thoracotomy was reopened, and an approach to the right atrium performed while surface cooling was continued. Electrosurgical dissection was used to isolate the cranial and caudal vena cavae as well as the terminal end of the azygous vein as it coursed into the junction of the cranial cava and right atrium. Moistened umbilical tape was passed separately around each vessel and secured with Rumel tourniquets. Use of TEE in real time allowed the surgeon to depress the lateral atrial wall with a finger. The finger pressure could be viewed as it related to the orientation of the ASD, and the pathological geometry could be determined. A double purse-string suture secured with Rumel tourniquets was again placed in the atrium so that a straight line from the purse-string suture in a caudomedial direction would intersect the middle of the ASD. A 12-F sheath introducera was then advanced through the atrial wall and secured with the purse-string suture–Rumel tourniquet combination. With TEE guidance, the introducer was advanced across the ASD into the left atrium where the first ASO disk was deployed, and with gentle backward tension, the second disk was deployed within the right atrium. The device was demonstrated to be securely deployed across the ASD by use of TEE but was not released from the deployment cable so that control of ASO position could be maintained.

Polytetrafluoroethylene-coated pledgets were sutured to the atrium at the proposed cranial and caudal limits of the atrial incision. The suture (4-0 polypropylene) was left attached to the pledgets. The suture was used to lift the atrial wall and to temporarily place it between the jaws of a large-size Satinsky side-biting vascular clamp.

In preparation for inflow occlusion and atriotomy, the dog was placed in a deep Trendelenburg position to minimize potential transport of air emboli to the head. The thoracic cavity was flooded with CO2 to displace any room air. Because the ASD provided a pathway for air to pass into the left side of the heart and then out the aortic valve, efforts were made to minimize the severity of any room air emboli by replacing the air in the thoracic cavity with more readily diffusible CO2. As a sensitive method to detect micro and macro air emboli, TEE was performed continuously throughout the procedure and there was no evidence of air emboli. The dog was hyperventilated for 2 minutes with 100% O2 to both reduce CO2 concentrations as well as maximize O2 content in the blood.

Tightening the 3 venous tourniquets commenced inflow occlusion. Ventilation was halted, and a timekeeper called out each 30-second interval. A planned time of < 6 minutes was deemed safe at the current core body temperature of 32°C.

The atrial wall was incised with a No. 11 scalpel blade, and the incision extended with Cooley scissors. The blood in the atrium was forced out with direct entry of the CO2 outflow catheter. The remaining blood was suctioned. The Cooley suction tip attached to a CO2 gas source (1.5 L/min) was left in the right atrial lumen to limit room air from crossing the ASD. Four sutures (4-0 polypropylene) were quickly placed through the nitinol wires of the ASO and into the remaining atrial septum (Figure 4). The area adjacent to the atrioventricular node was not sutured. The traction sutures were lifted, the CO2 source was removed from the thoracic cavity, and the atrium was flooded with blood by releasing the azygous tourniquet. As the final bubbles were flooded out of the right atrium, the Satinsky clamp was placed and the remaining tourniquets were released. During this time, TEE revealed no air emboli in the left atrium. Ischemic time was 4 minutes 30 seconds. Normal sinus rhythm was maintained throughout the procedure. Ventilation was commenced, and the heart was able to pump the venous blood as it was presented. Systemic blood pressures rapidly returned to physiologic values. The atrium was closed with redundant continuous sutures (4-0 polypropylene). The Satinsky clamp was removed, and complete hemostasis was observed.

Figure 4—
Figure 4—

Intraoperative photograph of the ASO (arrow) viewed through the open right atrium during suture placement within the atrium. Pledgets mark cranial (left) and caudal (right) limits of the atriotomy. The surgeon is standing on the dorsal side of the patient.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

The device position was reevaluated by TEE and then released from the delivery cable. The introducer was removed, and the purse string sutures closed. The thorax was closed in a routine manner. An autotransfusion machined (cell saver) was used, and 375 mL of packed washed RBCs was returned to the dog at the end of surgery.

The dog was managed for pain with a constant rate infusion of fentanyl, and treatment with gastrointestinal protectants was instituted because of the prolonged use of TEE during surgery. Recovery from anesthesia was prolonged, and substantial ventricular and supraventricular arrhythmias required specific treatment with antiarrhythmics. Initial antiarrhythmic treatment included a constant rate infusion of lidocaine and magnesium sulfate in combination with IV administration of procainamide and diltiazem. The dog maintained hemodynamic stability, and only ventricular arrhythmias persisted after the first 12 hours after surgery. Constant rate infusion of lidocaine and magnesium sulfate and IV administration of procainamide were continued as needed; administration of sotalol was initiated (0.89 mg/kg [0.41 mg/lb], PO, q 12 h). In addition, as planned, an antiplatelet dosage of aspirin (0.45 mg/kg [0.20 mg/lb], PO, q 24 h) was initiated the day after surgery. This was in accordance with standard medical treatment for all dogs undergoing transcatheter ASD closures and was continued for 6 months.

The day following surgery, TTE revealed good device position with some reductions in right atrial and ventricular size. By day 3 after surgery, the dog was cardiovascularly more stable, although the ventricular arrhythmias persisted. The dog was moved to the intermediate care unit and was doing well clinically. The following day, the dog continued to thrive and a second postoperative TTE was performed (fourth day after surgery) that revealed substantial reductions in right atrial and ventricular size to near normal proportions with resolution of pulmonary hypertension; however, there was a large curvilinear thrombus on the right atrial side of the device (Figure 5). The thrombus was thought to originate from the sutures. Hematologic evaluation revealed that the dog had thrombocytopenia, low serum fibrinogen concentration, and a prolonged prothrombin time and partial thromboplastin time. Administration of clopidogrel was initiated (1.67 mg/kg [0.76 mg/lb], PO, q 24 h), aspirin treatment was continued, and exercise was restricted to short walks on a leash. Serial TTE was performed over the next 4 days and revealed thrombus expansion (Figure 6). The dog did not develop clinical signs of thrombus or pulmonary thromboembolism; however, because of thrombus expansion, the dog was readmitted to the intensive care unit. Sotalol and aspirin administration were continued, the dose of clopidogrel was doubled (3.34 mg/kg [1.52 mg/lb], PO, q h), and treatment with doxycycline (4.46 mg/kg [2.02 mg/lb], PO, q 12 h) and dalteparin sodiume (98 U/kg [45 U/lb], SC, q 12 h) was initiated. Strict exercise restriction was also initiated. The dog continued to thrive, and although the coagulation profile results remained abnormal, the thrombus began to decrease in size and developed long mobile tags. The dog developed a cough that was attributed to pulmonary thromboembolism secondary to thrombus breakdown. Administration of dalteparin sodium was continued for 10 days and then discontinued because, in part, of financial constraints and the fact that the thrombus was much decreased in size and the cough was static. The dog was maintained in the intensive care unit for 5 additional days while receiving clopidogrel, aspirin, sotalol, and doxycycline. After that time, the dog was moved to the intermediate care unit to await hospital discharge. The dog was discharged 30 days following successful ASO implantation and had a residual thrombus (Figure 7). Thoracic radiography at the time of discharge revealed good device position and resolution of cardiomegaly and pulmonary overcirculation. Clopidogrel and sotalol administration were continued for 2 months, and aspirin administration was continued for 6 months. To date, the dog has done well for 10 months without clinical signs of heart failure or pulmonary thromboembolism and is currently not receiving any medications.

Figure 5—
Figure 5—

Left apical 4-chamber TTE image. Notice the curvilinear (dumbbell-shaped) thrombus (arrows) on the right atrial side of the ASO. The ASO is appropriately positioned across the ASD, and the right atrial and ventricular volume overload have almost resolved. See Figure 1 for key.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

Figure 6—
Figure 6—

Left apical 4-chamber TTE image. Notice the large thrombus (arrows) completely covering the right atrial side of the ASO and filling a large portion of the right atrium. The ASO continues to be appropriately positioned across the ASD. See Figure 1 for key.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

Figure 7—
Figure 7—

Left apical 4-chamber TTE image. Notice the residual thrombus (arrows) at the time of hospital discharge. The thrombus is now cavitated and still adherent to the right atrial side of the ASO but now occupies less of the right atrial volume. The ASO continues to be appropriately positioned across the ASD. See Figure 1 for key.

Citation: Journal of the American Veterinary Medical Association 236, 4; 10.2460/javma.236.4.434

Discussion

Atrial septal defect is a rare congenital cardiovascular defect in dogs. Its prevalence has been reported to vary from 0.7% to 3.7% of all congenital cardiovascular defects in dogs.2–4 The prevalence is reportedly higher in specific breeds, including Standard Poodles and Boxers.2,3,f The long-term prognosis for dogs with isolated small-sized ASD is usually good but can be compromised by the presence of concurrent congenital or adult onset cardiac disease. Dogs with defects > 12 mm may develop clinical signs of heart disease, including respiratory distress, exercise intolerance, and failure to thrive. However, many dogs have no obvious clinical signs until > 3 to 5 years of age.2–5,f

Traditionally, open heart surgery under cardiopulmonary bypass has been performed to close large ASDs in dogs.6 However, limited procedure availability and high postoperative morbidity have limited this approach. Transcatheter ASD closure by use of the same ASOb as in the present report has been described previously for dogs.5,7 The ASOb used in our study is a selfexpandable, double disk, nitinol wire mesh device filled with a thrombogenic polyester material. The size of the ASO is determined by its deployed waist size (3 to 38 mm diameter). The ASO is deployed with a 6- to 12-F sheath introducer delivery system.a

Recommended dog selection criteria for transcatheter ASD closure with an ASO are predominantly related to identification of a hemodynamically substantial left to right shunting ASD along with adequate rim tissue. To ensure secure ASO deployment, adequate rim tissue is defined as rim tissue around a minimum of 75% of the ASD circumference. Additionally, the ASD should not have a size estimate in excess of 38 mm (largest available ASO). Evaluation of these criteria is typically accomplished by use of a combination of transthoracic echocardiography and TEE and ASD balloon sizing under fluoroscopic guidance at the time of the procedure. A large ASD in particular may have insufficient rim tissue to allow transcatheter ASD closure by use of an ASO.

Open heart patch repair requires cardiopulmonary bypass. This approach is not routinely available and results in a high degree of morbidity. The modified hybrid procedure reported herein may represent a viable alternative to open heart patch repairs under cardiopulmonary bypass in situations when it is not available or it is declined or in lieu of euthanasia. The 2 life-threatening complications incurred by the dog of this report were severe arrhythmias and thrombus formation on the device (most likely associated with the sutures). Severe arrhythmias can usually be managed and may have been worse than anticipated in this dog because of the preceding long anesthetic procedure and atriotomy 7 days prior to the modified ASO implantation procedure. Arrhythmias may have also been related to coronary air emboli, although no air emboli were seen with continuous TEE imaging throughout the procedure. Arrhythmias in the dog of this report were worse than those associated with other atriotomies the authors have performed under temporary inflow occlusion. The rapidity and severity of thrombus formation were not anticipated in this dog. Although intraprocedural administration of heparin and postoperative administration of aspirin are routinely used in transcatheter ASD closure, this protocol is likely not sufficient when the modified approach is used and could be addressed prophylactically by administration of clopidogrel with a loading protocol before surgery and administration of dalteparin sodium during surgery.g Thrombogenesis in this dog may have been potentiated by the prior atriotomy. Finally, the risk of room air emboli in this procedure, although minimized by patient positioning and flooding of the right atrium and thorax with CO2, does represent a limitation of this procedure that could contribute to postoperative morbidity or even death. Prospective evaluation of clinical outcome in more dogs is required to better define the usefulness of this novel procedure for closure of large ASDs in dogs.

ABBREVIATIONS

ASD

Atrial septal defect

ASO

Atrial septal occluder

TEE

Transesophageal echocardiography

TTE

Transthoracic echocardiography

a.

Supersheath XL, 12-F sheath introducer, Boston Scientific Corp, Natick, Mass.

b.

Amplatzer Atrial Septal Occluder and Delivery System, AGA Medical Corp, Minneapolis, Minn.

c.

Argyle straight thoracic catheter, Tyco/Healthcare-Kendall, Mansfield, Mass.

d.

Terumo Frezenius, autotransfusion machine (cell saver), Sorin Group Italia SRL, Mirandola (Mo), Italy.

e.

Fragmin, Pfizer Inc, New York, NY.

f.

Gordon SG, Miller MW, Meurs K, et al. Atrial septal defects in an extended family of standard poodles (abstr). J Vet Intern Med 2006;20:730.

g.

Goodwin JC, Hogan HW, Green HW. The pharmacodynamics of clopidogrel in the dog (abstr). J Vet Intern Med 2007;22:609.

References

  • 1.

    Hill JA, Lambert CR, Vlietstra RE, et al. Review of general catheterization techniques. In: Pepine CJ, Hill JA, Lambert CR, eds. Diagnostic and therapeutic cardiac catheterization. 3rd ed. Baltimore: Williams & Wilkins, 1998;107.

    • Search Google Scholar
    • Export Citation
  • 2.

    Buchanan J. Prevalence of cardiovascular disorders. In: Fox PR, Sisson D, Moise NS, eds. Textbook of canine and feline cardiology. 2nd ed. Philadelphia: WB Saunders Co, 1999;457470.

    • Search Google Scholar
    • Export Citation
  • 3.

    Oyama MA, Sisson DD, Thomas WP, et al. Congenital heart disease. In: Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal medicine. 6th ed. St Louis: Elsevier, 2005;9711021.

    • Search Google Scholar
    • Export Citation
  • 4.

    Guglielmini C, Diana A, Pietra M, et al. Atrial septal defect in five dogs. J Small Anim Pract 2002;43:317322.

  • 5.

    Sanders RA, Hogan DE, Green HW III, et al. Transcatheter closure of an atrial septal defect in a dog. J Am Vet Med Assoc 2005;227:430434.

  • 6.

    Eyster GE, Anderson LK, Krehbeil JD, et al. Surgical repair of atrial septal defect in a dog. J Am Vet Med Assoc 1976;169:10811084.

  • 7.

    Gordon SG, Miller MW, Roland RM, et al. Transcatheter atrial septal defect closure with the Amplatzer atrial septal occluder in 13 dogs: short- and mid-term. J Vet Intern Med 2009;23:9951002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Figure 1—

    Right parasternal 4-chamber TTE image. Right atrial and ventricular dilation with a large (arrow) ASD is evident. LA = Left atrium. LV = Left ventricle. RA = Right atrium. RV = Right ventricle.

  • Figure 2—

    Preoperative right lateral (A) and ventrodorsal (B) radiographic views of the thorax. Notice the moderate generalized cardiomegaly with accentuation of the right atrium and ventricle and of the pulmonary trunk. The peripheral pulmonary blood vessels are mildly accentuated consistent with overcirculation associated with a left to right shunt. As an incidental finding, there are multiple metallic objects in the left craniodorsal portion of the abdomen presumed to be vascular clips.

  • Figure 3—

    Intraoperative photograph of the modified thoracic catheter secured in the right atrium.

  • Figure 4—

    Intraoperative photograph of the ASO (arrow) viewed through the open right atrium during suture placement within the atrium. Pledgets mark cranial (left) and caudal (right) limits of the atriotomy. The surgeon is standing on the dorsal side of the patient.

  • Figure 5—

    Left apical 4-chamber TTE image. Notice the curvilinear (dumbbell-shaped) thrombus (arrows) on the right atrial side of the ASO. The ASO is appropriately positioned across the ASD, and the right atrial and ventricular volume overload have almost resolved. See Figure 1 for key.

  • Figure 6—

    Left apical 4-chamber TTE image. Notice the large thrombus (arrows) completely covering the right atrial side of the ASO and filling a large portion of the right atrium. The ASO continues to be appropriately positioned across the ASD. See Figure 1 for key.

  • Figure 7—

    Left apical 4-chamber TTE image. Notice the residual thrombus (arrows) at the time of hospital discharge. The thrombus is now cavitated and still adherent to the right atrial side of the ASO but now occupies less of the right atrial volume. The ASO continues to be appropriately positioned across the ASD. See Figure 1 for key.

  • 1.

    Hill JA, Lambert CR, Vlietstra RE, et al. Review of general catheterization techniques. In: Pepine CJ, Hill JA, Lambert CR, eds. Diagnostic and therapeutic cardiac catheterization. 3rd ed. Baltimore: Williams & Wilkins, 1998;107.

    • Search Google Scholar
    • Export Citation
  • 2.

    Buchanan J. Prevalence of cardiovascular disorders. In: Fox PR, Sisson D, Moise NS, eds. Textbook of canine and feline cardiology. 2nd ed. Philadelphia: WB Saunders Co, 1999;457470.

    • Search Google Scholar
    • Export Citation
  • 3.

    Oyama MA, Sisson DD, Thomas WP, et al. Congenital heart disease. In: Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal medicine. 6th ed. St Louis: Elsevier, 2005;9711021.

    • Search Google Scholar
    • Export Citation
  • 4.

    Guglielmini C, Diana A, Pietra M, et al. Atrial septal defect in five dogs. J Small Anim Pract 2002;43:317322.

  • 5.

    Sanders RA, Hogan DE, Green HW III, et al. Transcatheter closure of an atrial septal defect in a dog. J Am Vet Med Assoc 2005;227:430434.

  • 6.

    Eyster GE, Anderson LK, Krehbeil JD, et al. Surgical repair of atrial septal defect in a dog. J Am Vet Med Assoc 1976;169:10811084.

  • 7.

    Gordon SG, Miller MW, Roland RM, et al. Transcatheter atrial septal defect closure with the Amplatzer atrial septal occluder in 13 dogs: short- and mid-term. J Vet Intern Med 2009;23:9951002.

    • Crossref
    • Search Google Scholar
    • Export Citation

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