Influence of Beta Blockers on Survival in Dogs with Severe Subaortic Stenosis

Abstract

BackgroundSubaortic stenosis (SAS) is one of the most common congenital cardiac defects in dogs. Severe SAS frequently is treated with a beta adrenergic receptor blocker (beta blocker), but this approach largely is empirical.ObjectiveTo determine the influence of beta blocker treatment on survival time in dogs with severe SAS.MethodsRetrospective review of medical records of dogs diagnosed with severe, uncomplicated SAS (pressure gradient [PG] ≥80 mmHg) between 1999 and 2011.ResultsFifty dogs met the inclusion criteria. Twenty‐seven dogs were treated with a beta blocker and 23 received no treatment. Median age at diagnosis was significantly greater in the untreated group (1.2 versus 0.6 years, respectively; P = .03). Median PG at diagnosis did not differ between the treated and untreated groups (127 versus 121 mmHg, respectively; P = .2). Cox proportional hazards regression was used to identify the influence of PG at diagnosis, age at diagnosis, and beta blocker treatment on survival. In the all‐cause multivariate mortality analysis, only age at diagnosis (P = .02) and PG at diagnosis (P = .03) affected survival time. In the cardiac mortality analysis, only PG influenced survival time (P = .03). Treatment with a beta blocker did not influence survival time in either the all‐cause (P = .93) or cardiac‐cause (P = .97) mortality analyses.ConclusionsBeta blocker treatment did not influence survival in dogs with severe SAS in our study, and a higher PG at diagnosis was associated with increased risk of death.

Aortic Stenosis in Dogs and Cats: Past, Present and Future

“…Administration of beta-blockers can decrease heart rate, prolong diastole and coronary filling, thereby reducing myocardial hypoxia and protect against arrhythmia. Dogs do clinically well on beta-blockers; however, a study proved no benefit in terms of survival versus untreated dogs with severe SAS [59]. There is no literature on evaluation of other medical treatment.…”

Breed does not affect the association between murmur intensity and disease severity in dogs with pulmonic or subaortic stenosis

“…The severity of stenosis ranges from “equivocal” to “severe” (Hollmer et al , Stern et al , ), and outcomes for dogs with pulmonic or subaortic stenosis are dependent on the severity. In most cases, mild stenosis is well tolerated and infrequently affects survival, whereas severe stenosis can result in sudden death or, rarely, congestive heart failure and often warrants medical, surgical or endovascular intervention (Kienle et al , Johnson et al , Eason et al ). Both forms of stenosis present with murmurs, and screening exams usually rely on the accurate characterisation of the murmurs, both in intensity and location.…”

Sound advice for heart murmurs

“…) of aortic stenosis in dogs have failed to show a survival benefit over medical therapy (beta‐blockers), while a recent study of dogs with aortic stenosis showed no survival benefit for therapy with beta‐blockers over no therapy (Eason et al . ). Furthermore, some interventional procedures are associated with perioperative risk, including cardiopulmonary arrest (Margiocco et al .…”