Download INTERVENTIONAL CLOSURE

Veterinary Cardiorespiratory Centre
Martin Referral Services, Thera House, 43 Waverley Road, Kenilworth, Warwickshire CV8 1JL
Tel: 01926 863445
INFORMATION SHEET - VETS
INTERVENTIONAL CLOSURE OF PATENT DUCTUS ARTERIOSUS
Indications
Closure of a PDA is indicated in virtually all cases as the yearly mortality rate in untreated cases is
approximately 50%.
The most common outcome for dogs in which a PDA is not closed is the development of cardiomegaly and
left sided congestive heart failure. Closure can still be performed in these cases provided the left
ventricular contractility is still good and there is not excessive cardiomegaly. The development of
pulmonary hypertension and thus a reverse shunting (ie. right-to-left) PDA is uncommon - but this is a
contraindication to closure. Those dogs that do develop pulmonary hypertension do so by 6 months of age
and this seems not to be related to the size of the PDA but probably genetic factors.
Outcome
The Veterinary Cardiorespiratory Centre is one of the few specialist centres in the UK to regularly perform
interventional closure of PDAs (transcatheter embolisation). This is a difficult intervention and better
results will be achieved with an experienced veterinary cardiologist. Direct surgical closure is still
available, however this is associated with a mortality rate of 3 - 8% (depending upon the surgeon) and an
extended recovery time from the thoracotomy. Interventional closure appears to have an even lower
associated mortality rate and dogs can return home the following day with no after-effects or pain. In
addition owners do tend to prefer ‘keyhole’ surgery.
Closure device
There are an increasing number of embolisation devices for closure of PDAs and this continues to be an
area undergoing advances in paediatric cardiology, and we are keeping abreast of these developments.
Cook coils (detachable and non-detachable) are currently the main devices use in children and dogs,
however newer devices are Amplatzer occluders and vascular plugs. These range in price and which one is
most effective for which case depends upon the size and shape of the duct (certain breeds of dogs have
larger ducts). This decision is generally made after angiographic studies have been performed.
Complications
There can be some bruising and swelling around the femoral incision. Haematuria has been reported, but
seems to be rare. Loss of a coil into the pulmonary artery circulation is uncommon and to date has only
been reported with the non-detachable Cook coils. Residual flow is not uncommon with coils, but the
amount of flow is usually insignificant.
Prior to surgery
We prefer not to undertake anaesthesia in animals that are in congestive heart failure (pulmonary oedema
or ascites). Thus it is useful to obtain chest x-rays to screen for cardiomegaly and/or congestive heart
failure in case diuresis is required prior to anaesthesia. If congestive heart failure is present at time of
referral surgery will be postponed until this is satisfactorily controlled.
The dog should be free of any infections especially pyodermas and skin parasites - if present these should
be treated before surgery can proceed.
Post surgery follow-up
Sutures from the femoral area are due for removal 8 to 10 days post surgery.
If dogs are presented in heart failure and have been on medication, this should be continued until follow-up
echocardiography and chest x-rays have been obtained.
References
French A, Martin M et al (2001). Paper presentation: Coil embolisation of PDAs in dogs. European Society of Veterinary Cardiology, Dublin.
Glaus TM, Martin M, et al (2003) Catheter closure of patent ductus arteriosus in dogs: variation in ductal size requires different techniques.
Journal of Veterinary Cardiology 5, 7-12.
Martin, Johnson & Tofeig. (April 2003) My experience in the use of the Amplatzer occluder in dogs with very larges PDAs. Veterinary
Cardiovascular Society, Birmingham.