Study questions urine sodium as a stage B2 MMVD marker

Urinary sodium markers fell short as a screening tool for preclinical stage B2 myxomatous mitral valve disease in a new prospective study published in Frontiers in Veterinary Science. Investigators compared spot urine sodium concentration, the urine sodium-to-potassium ratio, and a corrected urine sodium measure in healthy dogs and dogs with ACVIM stage B2 MMVD, and found no significant differences between groups. The study also found limited associations between those urinary sodium indices and echocardiographic measures of disease severity, suggesting the markers have little practical value for distinguishing stage B2 MMVD from healthy dogs under routine clinical conditions. (frontiersin.org)

Why it matters: For veterinarians, that’s a useful negative finding. Stage B2 MMVD is the point at which treatment decisions become more consequential, because ACVIM guidance defines it as asymptomatic disease with cardiac enlargement severe enough to justify starting pimobendan, based on evidence that earlier treatment can delay the onset of congestive heart failure. This study suggests spot urine sodium testing is unlikely to help clinicians identify those dogs or serve as a dependable surrogate for preclinical neurohormonal activation, reinforcing that staging still depends on imaging and established clinical criteria rather than a simple urine-based shortcut. (vdc.vet)

What to watch: Expect continued interest in practical biomarkers for earlier MMVD staging, but for now, echocardiographic and radiographic criteria remain the standard for identifying true stage B2 patients. (vdc.vet)