Long-term palliation of tetralogy of Fallot in dogs by use of a modified Blalock-Taussig shunt

Daniel J. Brockman Department of Clinical Science, Royal Veterinary College, North Mymms, Hatfield, Hertfordshire, AL9 7TA, England

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David E. Holt Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6010

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J. William Gaynor The Children's Hospital of Philadelphia, 34th St and Civic Center Blvd, Philadelphia, PA 19104-4399

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Terrill E. Theman Cardiovascular and Thoracic Surgical Associates of St Luke's Hospital, 701 Ostrum St, Ste 201, Bethlehem, PA 18015

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Abstract

Objective—To describe a modified Blalock-Taussig shunt (mBT) procedure and assess its use in dogs with clinical signs associated with tetralogy of Fallot (TOF).

Design—Descriptive report.

Animals—6 dogs with severe TOF-associated clinical signs.

Procedures—Each dog had TOF (confirmed echocardiographically or angiographically) and underwent an mBT shunt procedure for surgical palliation of signs. The surgery was performed through a left fourth rib resection or a left fifth intercostal thoracotomy. The left subclavian artery was dissected free from surrounding mediastinal tissue. The main pulmonary artery trunk was exposed through an incision in the overlying pericardium. A shunt comprised of a 6-mm-diameter tube of expanded polytetrafluoroethylene (5 dogs) or a segment of carotid artery (1 dog) was sutured end to side between the left subclavian artery and pulmonary artery trunk.

Results—5 of the 6 dogs survived the immediate postoperative period. The dog that died shortly after surgery was the smallest of the dogs (weight, 2.9 kg [6.38 lb]) and had received the carotid artery autograft. Three dogs survived long term and 2 dogs died of unknown causes 6 years after undergoing the mBT shunt procedure. In all dogs that survived the mBT procedure, shunt patency was confirmed and quality of life appeared improved.

Conclusions and Clinical Relevance—These findings have suggested that the mBT shunt procedure safely provides long-term palliation of TOF-associated clinical signs in dogs. In addition, it may offer an effective low-risk and lower-cost alternative to open heart repair of TOF.

Abstract

Objective—To describe a modified Blalock-Taussig shunt (mBT) procedure and assess its use in dogs with clinical signs associated with tetralogy of Fallot (TOF).

Design—Descriptive report.

Animals—6 dogs with severe TOF-associated clinical signs.

Procedures—Each dog had TOF (confirmed echocardiographically or angiographically) and underwent an mBT shunt procedure for surgical palliation of signs. The surgery was performed through a left fourth rib resection or a left fifth intercostal thoracotomy. The left subclavian artery was dissected free from surrounding mediastinal tissue. The main pulmonary artery trunk was exposed through an incision in the overlying pericardium. A shunt comprised of a 6-mm-diameter tube of expanded polytetrafluoroethylene (5 dogs) or a segment of carotid artery (1 dog) was sutured end to side between the left subclavian artery and pulmonary artery trunk.

Results—5 of the 6 dogs survived the immediate postoperative period. The dog that died shortly after surgery was the smallest of the dogs (weight, 2.9 kg [6.38 lb]) and had received the carotid artery autograft. Three dogs survived long term and 2 dogs died of unknown causes 6 years after undergoing the mBT shunt procedure. In all dogs that survived the mBT procedure, shunt patency was confirmed and quality of life appeared improved.

Conclusions and Clinical Relevance—These findings have suggested that the mBT shunt procedure safely provides long-term palliation of TOF-associated clinical signs in dogs. In addition, it may offer an effective low-risk and lower-cost alternative to open heart repair of TOF.

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