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Outcome of dogs with PDA | VETgirl Veterinary CE Podcasts

In this VETgirl podcast, we review patent ductus arteriosus (PDA) and the long-term outcome. Should you be recommending your puppies for PDA closure?

PDA is a congenital cardiac anomaly that allows for left-to-right shunting of blood from the descending aorta to the main pulmonary artery (in most cases). This results in volume overload to the left sided cardiac chambers, and ultimately, congestive heart failure, if left untreated. Left sided cardiac dimensions are usually significantly reduced following PDA closure and outcome is generally considered good in dogs but published data on long-term outcome is limited and factors affecting this outcome have not been well investigated. So what’s the outcome? Before my client spends a few thousand for a coil, is it worth it?

So, Saunders et al out of Texas A&M wanted to evaluate the  long-term outcome, and the factors affecting this outcome, in a large group of dogs with PDA. In this study, they retrospectively evaluated 520 dogs (with the majority of them – 513 – having a left-to-right PDA). The top dogs represented: Bichon Frise, mixed breed, Chihuahua, Poodle, and German shepherd. The majority of dogs (87.7%) had closure attempted via catheter-based procedures (e.g., such as coils, ductal occluders, etc) or surgical ligation. The good news? The majority of dogs survived immediately post-operatively (with a 3-day post-operative mortality of 2.6%). Most importantly? This study found that it worked: PDA closure resulted in a median survival time of 12 years, as compared to only 2 years when the PDA was not surgically corrected! This study also found that not having PDA closure and presence of other congenital HD at time of diagnosis were negatively correlated with survival. Another finding? If clinical signs already exist at the time of presentation for referral, or if the dog has concurrent congenital HD, or severe mitral regurgitation within 24 hours of the procedure, there was a decreased survival.

So, what’s VETgirl’s take on this? Diagnose the PDA fast, and encourage closure ASAP! Don’t wait for clinical signs to develop, and encourage your pet owners to proceed, as the survival is dramatically longer once corrected.

Overall, findings from this study are similar to previous studies in demonstrating a significant survival benefit to the PDA patient with closure of the PDA (by either method) and significant (although not always complete) reverse remodeling of cardiac enlargement in most patients following closure. With PDA closure, preload is significantly reduced but afterload actually increases, which can result in a significant decrease in left ventricular systolic function following closure. This is of particular concern for PDA patients with evidence of left ventricular dysfunction on baseline evaluation (pre-closure).

What we liked about this study? This study is of relatively large size and confirms some of the previously reported survival data for dogs undergoing PDA closure. In short, PDA closure is highly successful, provides excellent long-term survival in most cases, and NOT closing a canine PDA results in markedly shortened life span. It is not surprising that the presence of concurrent other congenital heart disease, symptoms pre-closure, or significant mitral regurgitation post-operatively would correlate with worse survival as these will complicate short and long-term hemodynamics and management techniques. It is also not surprising that parameters of systolic function prior to closure were highly predictive of these same parameters prior to closure for all dogs. It’s important to note that systolic dysfunction pre-closure did not appear to result in worse clinical outcome, however. This conclusion must be interpreted with caution as only a small number of dogs in the study had reduced systolic function pre-closure.

Copyright, VETgirl, 2014.

Suggested reading:

1. Saunders AB, Gordon SG, Boggess MM, et al. Long-term outcome in dogs with patent ductus arterioles: 520 cases (1994-2009)J Vet Intern Med 2014;28(2):401-410.

2. White P. Treatment of patent ductus arterioles by the use of an Amplatz canine ductal occluder device. Can Vet J2009; 50(4): 401–404.

Great client handouts on PDA:

UMINNhttp://www.cvm.umn.edu/vmc/prod/groups/cvm/@pub/@cvm/documents/asset/cvm_asset_317435.pdf

Animal Medical Centerhttp://www.animalmedcenter.com/faqs/category/patent-ductus-arteriosis-surgery

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