Comparison of peak flow velocity through the left ventricular outflow tract and effective orifice area indexed to body surface area in Golden Retriever puppies to predict development of subaortic stenosis in adult dogs

• Autores: Romain Javard
• Localización: JAVMA: Journal of the American Veterinary Medical Association, ISSN-e 0003-1488, Vol. 245, Nº. 12, 2014, págs. 1367-1374
• Idioma: inglés
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• Resumen

  • Objective—To evaluate the usefulness of Doppler-derived peak flow velocity through the left ventricular outflow tract (LVOT Vmax) and effective orifice area indexed to body surface area (EOAi) in puppies to predict development of subaortic stenosis (SAS) in the same dogs as adults.

    Design—Prospective, longitudinal, observational study.

    Animals—38 Golden Retrievers.

    Procedures—Cardiac auscultation and echocardiography were performed on 2- to 6-month-old puppies, then repeated at 12 to 18 months. Subaortic stenosis was diagnosed when LVOT Vmax was ≥ 2.3 m/s in adult dogs with left basilar systolic murmurs.

    Results—All puppies with EOAi < 1.46 cm2/m2 had SAS as adults. All adults with EOAi < 1.29 cm2/m2 had SAS. An LVOT Vmax > 2.3 m/s in puppyhood was 63% sensitive and 100% specific for SAS in adulthood. In puppies, LVOT Vmax was more strongly associated with a future diagnosis of SAS (area under the curve [AUC], 0.89) than was EOAi (AUC, 0.80). In puppies, the combination of LVOT Vmax and EOAi yielded slightly higher sensitivity (69%) and specificity (100%) for adult SAS than did LVOT Vmax alone. In unaffected and affected dogs, LVOT Vmax increased significantly from puppyhood to adulthood but EOAi did not.

    Conclusions and Clinical Relevance—In Golden Retriever puppies, LVOT Vmax > 2.3 m/s and EOAi < 1.46 cm2/m2 were both associated with a diagnosis of SAS at adulthood. The combination of these 2 criteria may result in higher sensitivity for SAS screening. Unlike LVOT Vmax, EOAi did not change during growth in either unaffected Golden Retrievers or those with SAS.

    Subaortic stenosis is one of the most common congenital heart defects in Golden Retrievers.1,2 It appears to be inherited in this breed.3 Subaortic stenosis is a progressive defect, and the stenosis phenotype typically develops in the first months after birth.1,4–9 Because of its progressive nature, early detection of SAS remains challenging, and assessment prior to 1 year of age may underestimate its severity or fail to identify its existence altogether.6 Whereas mild and moderate forms of the disease are associated with a good prognosis, many dogs with severe SAS die suddenly, often within the first 3 years after birth.1 Definitive diagnosis of SAS typically involves Doppler echocardiography, but clear criteria for SAS screening in dogs are controversial.1,3,6 Despite being highly flow dependent, measurement of LVOT Vmax or left ventricular-to-aortic pressure gradient is commonly used as the principal diagnostic means to assess the severity of SAS and establish a prognosis.4,10 In human medicine, valvular EOA is often considered a better indicator of aortic stenosis severity than LVOT Vmax or pressure gradient because it is less flow dependent.11–13 It has been demonstrated that the LVOT EOAi is an accurate indicator of SAS severity in dogs.14 However, because of the potentially progressive nature of the disease during growth, the usefulness of EOAi in puppies as an early marker for SAS is unknown. The aim of the study reported here was to evaluate and compare the LVOT Vmax and EOAi measured in Golden Retriever puppies as a predictor of SAS at adulthood.