Pimobendan in preclinical MMVD (stage B2): delaying heart failure — PROBABLE

In dogs with stage B2 myxomatous mitral valve disease, does pimobendan vs placebo delay the onset of congestive heart failure or cardiac death?

Shelf #201 · gate-verified and approved by the developer

PROBABLE: Pimobendan delays the onset of heart failure in dogs with preclinical myxomatous mitral valve disease and cardiomegaly. In EPIC, a prospective, randomized, placebo-controlled, blinded, multicenter trial of 360 dogs, the median time to the composite primary endpoint (onset of congestive heart failure, cardiac-related death, or euthanasia) was 1228 days on pimobendan vs 766 days on placebo (hazard ratio 0.64, 95% CI 0.47-0.87; P = .0038) — a 36% relative reduction in hazard, with the absolute median prolongation of the preclinical period about 15 months — and median survival time was also longer (1059 vs 902 days; P = .012). One large decisive blinded placebo-controlled trial with a hard composite endpoint is exactly the charter's PROBABLE case. This pack is Tier C because its claim includes cardiac death and survival. Drafted Nov 10, 2026 (VetMed build, topic #201); all figures from abstracts fetched and verified at drafting.

EPIC (Boswood 2016): pimobendan prolonged the preclinical period by a median of about 15 months in 360 dogs with stage B2 MMVD

Prospective, randomized, placebo-controlled, blinded, multicenter clinical trial (EPIC)

Who: Dogs: 360 client-owned dogs with myxomatous mitral valve disease and cardiomegaly — left atrial-to-aortic ratio >=1.6, normalized left ventricular internal diameter in diastole >=1.7, and vertebral heart sum >10.5 — not receiving other cardiovascular medications; pimobendan 0.4-0.6 mg/kg/day in divided doses vs placebo.

Result: Median time to the primary endpoint (composite of onset of congestive heart failure, cardiac-related death, or euthanasia) was 1228 days (95% CI: 856-NA) in the pimobendan group and 766 days (95% CI: 667-875) in the placebo group (P = .0038). The hazard ratio for the pimobendan group was 0.64 (95% CI: 0.47-0.87) — a 36% relative reduction in hazard — and the benefit persisted after adjustment for other variables. Dogs in the pimobendan group lived longer: median survival time 1059 days (95% CI: 952-NA) vs 902 days (95% CI: 747-1061) (P = .012). Adverse events were not different between treatment groups.

Watch out: The entry criteria are specific (enlarged left atrium and ventricle by the stated cut-offs): the result does not extend to stage B1 dogs without cardiomegaly. The survival figure is all-cause median survival time as reported in the abstract, secondary to the composite primary endpoint.

Boswood A, Häggström J, Gordon SG et al. Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study-A Randomized Clinical Trial. J Vet Intern Med. 2016;30(6):1765-1779. PMID: 27678080. Registry ID: none in the record. MeSH: Animals · Cardiomegaly · Cardiotonic Agents · Dog Diseases · Dogs · Female · Heart Failure · Male · Mitral Valve Insufficiency · Pyridazines

Synthesis: a single decisive blinded placebo-controlled trial carries this shelf (the VetMed single-trial exception)

Synthesis

Who: Synthesis of the card above: EPIC (Boswood 2016), the single trial on this shelf — a prospective, randomized, placebo-controlled, blinded, multicenter trial of 360 dogs.

Result: This shelf rests on one trial, stated on its face. EPIC is large for veterinary cardiology, blinded and placebo-controlled, and its primary endpoint is a hard clinical composite (heart failure onset, cardiac death, or euthanasia), met with a hazard ratio of 0.64 and a median prolongation of the preclinical period of about 15 months (1228 vs 766 days), with median survival also longer (1059 vs 902 days). Under the VetMed charter's single-trial exception, a trial of this force carries a benefit shelf at PROBABLE. The survival component makes the pack Tier C.

Watch out: A single trial, however strong, has not been replicated in this exact population; dogs without cardiomegaly (stage B1) were not studied, and EPIC does not answer whether other drugs started at B2 add anything.

Synthesis of Boswood A et al. PMID: 27678080. Registry ID as on the individual card.

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