Comparison of diameter and length of subclavian arteries to external jugular veins in variably sized dogs: A cadaveric study.

OBJECTIVE: To evaluate the length and diameter of a left external jugular vein graft as a substitute for the left subclavian artery in the modified Blalock-Thomas-Taussig shunt (mBTTS) in differently sized dogs. STUDY DESIGN: Cadaveric study. ANIMALS: Dog cadavers of three weight categories (10/group): <9.5 kg, 9.5 to 27 kg, and > 27 kg. METHODS: The length and infused external diameters of harvested vessels were measured with vernier calipers and recorded. A matched-pairs t test was used to test the difference in vessel lengths. The agreement in vessel diameters was assessed by using Lin's concordance correlation coefficient (CCC). Pearson's correlation coefficients (CC) were determined for vessel diameter to weight category and vessel length to weight category. RESULTS: The external jugular vein measured longer than the subclavian artery in all dogs (52.0 ± 20.8 mm and 23.0 ± 8.9 mm, respectively), with a mean difference of 28 ± 14.3 mm (P < .001). The mean external infused subclavian and external jugular diameters measured 7.8 ± 2.2 mm and 8.0 ± 2.5 mm, respectively (P = .32). Lin's CCC was 0.87. Pearson's CC were 0.74 in both vessel diameters (P < .001); they were 0.36 and 0.43, respectively, for subclavian artery and external juglar vein length (P < .001). CONCLUSION: Autologous external jugular vein grafts had an external diameter similar to subclavian artery and a significantly longer length in variably sized dogs. CLINICAL SIGNIFICANCE: External jugular vein grafts may be an acceptable graft choice for mBTTS.

Canine mitral valve size as measured by computed tomography.

OBJECTIVE: To measure the mitral annulus in dogs. Our hypothesis was that mitral measurement would be possible and consistent among observers using CT. SAMPLE: Thoracic CT scans of dogs without known heart disease. PROCEDURES: Five trained investigators measured 4 aspects of the mitral valve and the fourth thoracic vertebrae (T4) length using multiplanar reformatting tools. Ten randomly chosen animals were measured by all investigators to determine interobserver reliability. RESULTS: There were 233 CT scans eligible for inclusion. Dogs weighed 2 to 96 kg (mean, 28.1 kg), with a variety of breeds represented. Golden Retrievers (n = 28) and Labrador Retrievers (n = 37) were overrepresented. The intraclass correlations were all greater than 0.9, showing excellent agreement between observers. The means and SDs of each measurement were as follows: trigone-to-trigone distance, 17.2 ± 4.7 mm; the remaining circumference, 79.0 ± 17.5 mm; commissure-to-commissure distance, 30.8 ± 6.5 mm; septal leaflet-to-lateral leaflet distance, 26.3 ± 6.0 mm; T4 length, 16.9 ± 3.1 mm; and the total circumference normalized by T4, 5.7 ± 0.7 mm. CLINICAL RELEVANCE: This study provides information that may help in the development of future treatment for mitral valve dysfunction and subsequent annular enlargement.