Caudal vena cava point-of-care ultrasound in dogs with degenerative mitral valve disease without clinically important right heart disease.

Objectives: Caudal vena cava (CVC) diameter and collapsibility index (CVC and CVC) have been used to assess intravascular volume status (IVS). Maladaptations with progressive degenerative mitral valve disease (DMVD) lead to hypervolemia. We hypothesised that stages of DMVD will affect ultrasonographic CVC variables in dogs without clinically important right heart disease.

Animals, Materials And Methods: This retrospective study included 79 dogs with DMVD presented to the cardiology department between January 2017 and 2019. Subxiphoid views were used to obtain CVC cineloops. By visual inspection, CVC was subjectively scored as flat, normal or fat. Maximal and minimal CVC were measured and indexed to aortic diameter (CVC and CVC); CVC was calculated as (CVC-CVC)/CVC. Fisher's exact and Kruskal-Wallis tests were used to compare CVC variables.

Results: Subjective assessment was associated with American College of Veterinary Internal Medicine (ACVIM) stages (P < 0.001). The proportion of fat CVC was greater in stages C and D. In stage D, CVC was larger compared with stages B1, B2 and C (P = 0.002, P = 0.002 and P = 0.035, respectively). In stages C and D, CVC was larger compared with B1 (P = 0.016 and P = 0.001) and B2 (P = 0.002 and P < 0.001. In stages C and D, CVC was less than stage B1 (P = 0.016 and P = 0.044) and B2 (P = 0.001 and P = 0.010).

Conclusions: In dogs with DMVD without clinically important right heart disease, CVC variables differ across ACVIM stage. Subjective and objective CVC variables may be used to predict hypervolemia.