Mario Vastano¹, Alex Brown², Jo Dukes McEwan¹, Siddharth Sudunagunta³, Alex German¹, Chris Linney²

¹University of Liverpool-Small Animal Teaching Hospital, Neston, United Kingdom. ²Paragon Veterinary Referrals, Wakefield, United Kingdom. ³Willows Veterinary Centre, Solihull, United Kingdom

Objectives

To identify clinical, echocardiographic and therapeutic variables causally associated with survival in UK-based French Bulldogs (FB) with pulmonic stenosis (PS).

Methods

Electronic records of FB with PS from three UK referral centers (2016–2024) were retrospectively reviewed.  Clinical, echocardiographic, and treatment data were analyzed using Bayesian multilevel, survival (time-to-event) models, with a directed acyclic graph used to inform covariable selection.  Hazard ratios and associated probabilities were estimated using Hamiltonian Monte Carlo.  The accuracy of estimates was improved by incorporating previous research findings into prior distributions.

Results

Of 113 study dogs, 78 underwent interventional management (59 balloon valvuloplasty, 21 transvalvular pulmonic stent angioplasty). Variables causally associated with shortened survival included clinical signs (hazard ratio [HR] 2.56; 89% highest density interval [89-HDI] 0.95,4.62; probability 97.8%), congestive heart failure (HR 3.65; 89-HDI 1.31,6.90; probability 99.7%) and concurrent congenital disease (HR 3.18; 89-HDI 1.64,5.11; probability >99.9%), but not stenosis type. Echocardiographic variables causally associated with shortened survival included Vmax-PV:Vmax-AV (HR 1.56; 89-HDI 1.20,1.91; probability 99.5%), end-diastolic right ventricular free wall thickness (HR 1.96; 89-HDI 1.39,2.58; probability 99.6%) and maximum right atrial diameter (HR 1.93; 89-HDI 1.23,2.73; probability 99.6%). Interventional management improved survival (HR 0.42; 89-HDI 0.16,0.73; probability 98.0%); suffering complications reduced survival (HR 3.24; 89-HDI 1.17,5.97; probability 99.2%), but atenolol had limited impact (HR 0.83; 89-HDI 0.23,1.78).

Statement: Impact/ Clinical Significance

Survival of FB with PS is causally-associated with disease severity, right-sided cardiac remodeling and non-flow dependent echocardiographic indices rather than stenosis type. Interventional management improves survival, unless complications occur, whilst beta-blocker therapy offers limited benefit.