Preductal Segmental Tubular Aortic Hypoplasia in Perinatally Died Stabyhoun Puppies

SIMPLE SUMMARY: Because of an unexplained rise in the death rate of newborn puppies of the Stabyhoun breed, one of the Dutch breeders’ organizations contacted the reporting institution for help. Consequently, eight Stabyhoun puppies that were stillborn, died or were euthanized within weeks after birth were submitted to post-mortem examination at the reporting institution over a period of 18 months. In five of the eight Stabyhoun puppies, the aorta, which is the largest artery of the body, showed a severe local narrowing in the chest. Narrowing of the aorta in dogs has extremely rarely been documented. Therefore, the relatively high rate of occurrence in these eight examined Stabyhoun puppies is an unexpected finding, which might have been caused by a genetic predisposition. In children, narrowing of the aorta is believed to develop as a result of constriction of an abnormally located muscle in the vascular wall at birth. If this constriction cannot happen before birth, this vascular anomaly cannot explain the death of the stillborn puppies. However, the condition might lead to heart failure and other clinical signs later in life. Because the aorta is not routinely examined at post-mortem examinations, the frequency of this anomaly in puppies is unknown. ABSTRACT: Background: A high perinatal mortality rate in the Stabyhoun breed prompted one of the Dutch breeding organizations to start an investigation. Preductal segmental tubular aortic hypoplasia is an extremely rarely documented congenital vascular anomaly in dogs, and it is suspected to be the result of constriction of ectopic ductal tissue in the aortic wall at birth. Methods: Over a period of 18 months, Stabyhoun puppies that were stillborn, died or were euthanized before 3 weeks of age were submitted to post-mortem examination at the reporting institution. Pathologic findings were documented. Results: Eight Stabyhoun puppies were submitted during the study period. In five of them, a severe preductal segmental tubular aortic hypoplasia was found. Two of the five puppies were stillborn, and three died spontaneously or were euthanized. Conclusions: Preductal tubular aortic hypoplasia was found in an unusually high frequency in the examined Stabyhoun puppies. Because the condition is believed to cause clinical signs only after birth, this anomaly cannot explain the death of the stillborn puppies. However, it might be responsible for cardiogenic pulmonary edema in the postnatal period. Routine dissection of the great vessels in perinatally deceased puppies would help to establish the prevalence of congenital anomalies of the aorta.