Patent ductus arteriosus

Veterinary PDA

1. Patent Ductus Arteriosus (PDA) Annie Thomson

2. Leo Stokesley 4 week old male entire Cavalier King Charles Spaniel Presented for investigation of heart murmur

3. History Slightly smaller than littermates No exercise intolerance Breeders felt he seemed like a normal healthy puppy Clinical Exam BAR, pink MMs, CRT <2sec Dynamic pulse quality Heart rate 204 bpm Grade VI continuous murmur over left heart base Resp rate 48 breaths/min NAD on auscultation of lungs Bodyweight 1.28kg

4. Leo’s Echocardiogram Left ventricular dilatation Turbulent flow in pulmonary artery Visualisation of PDA

5. Ductus arteriosus physiology Important part of foetal circulation Shunt between pulmonary trunk and aorta (R L) Allows deoxygenated blood to bypass the lungs and enter the aorta When first breath is taken: Aortic pressure increases Blood flows back into ductus arteriosus Ductus arteriosus pressure increases Walls of ductus arteriosus collapse Ductus arteriosus closes

6. PDA – Pathophysiology Ductus arteriosus fails to close at birth Patent v ascular channel connecting pulmonary artery and aorta Blood shunts L R Over-circulation of pulmonary vasculature and lung fields Volume overload in LHS of heart … Or blood shunts RL Left sided heart failure LV dilatation and mitral regurgitation LV myocardial failure LA enlargement Atrial fibrillation

7. PDA – Aetiology Proven to be hereditary in some breeds Miniature Poodles Genetic defect in structure of DA Polygenic Distinct sex predispostion for females (3:1) Predisposed breeds: Maltese Pomeranian Shetland Sheepdog English Springer Spaniel Bichon frise Poodle Yorkshire Terrier German Shepherd

8. PDA – Clinical Presentation History Poor growth compared to littermates Weight loss Exercise intolerance Coughing However in a lot of cases it is an incidental finding when puppy is in for first vaccination Clinical Signs Loud continuous murmur (grade V or VI) with PMI at dorsal left heart base Hyperdynamic femoral pulses Signs of left sided heart failure

9. PDA – Confirming the Diagnosis Clinical findings: Continuous grade V/VI heart murmur Thoracic radiography “triple knuckle” Cardiomegaly Distended pulmonary vessels +/- pulmonary oedema ECG Signs of left sided enlargement +/- arrhythmias Echocardiography B-mode and Doppler For specific diagnosis of PDA

10. PDA – Treatment Options Surgical ligation of PDA Percutaneous transarterial coil or plug occlusion of PDA Vascular occlusion coils Amplatz Canine Duct Occluder (ACDO) Treat congestive heart failure Furosemide Pimobendan (ACE inhibitors) (Spironolactone)

11. Surgical Ligation of PDA Thoracotomy Non-absorbable ligatures around ductus Referral procedure

12. Transarterial Occlusion of PDA Coil Occlusion Amplatz Canine Duct Occluder Catheter passed via femoral artery  aorta  ductus arteriosus Suitable size of occluder chosen Occluder released in DA Encourage embolus formation  ductus occlusion Referral procedure

13. Surgical ligation vs. Transarterial Occlusion Surgical Ligation Advantages (Shorter procedure time) High initial success rates Can be performed in animals <4kg Low mortality and morbidity rates Disadvantages Invasive Higher risk of major complications Transarterial Coil Occlusion Advantages Minimally invasive Lower risk of major complications Low mortality and morbidity rates Disadvantages Risk of coil embolising Cannot be used in dogs <4kg Amplatz Canine Duct Occluder Advantages Minimally invasive Lower risk of major complications Low mortality and morbidity rates Disadvantages Cannot be used in dogs <4kg

14. PDA – Prognosis Excellent Normal life span following correction Cardiac changes present prior to correction may or may not reverse Left ventricular systolic dysfunction Cardiomegaly/enlarged chamber size Mitral regurgitation Negative prognostic indicators: Confirmed CHF Age: > 2 years old? Weight: >23kg ?

15. Back to Leo… Surgical ligation at 12 weeks old Chest drain placed during surgery Post-op medications: Methadone Meloxicam Synulox Frusemide Pimobendan Rocky recovery Home on medication Booked in for repeat echo in 4 weeks time

16. References Saunders, A.B. et al. 'Long-Term Outcome In Dogs With Patent Ductus Arteriosus : 520 Cases (1994-2009)'.  Journal of Veterinary Internal Medicine  28.2 (2013): 401-410. Web . GOODRICH, KIMBERLY R. et al. 'Retrospective Comparison Of Surgical Ligation And Transarterial Catheter Occlusion For Treatment Of Patent Ductus Arteriosus In Two Hundred And Four Dogs (1993?2003)'.  Veterinary Surgery  36.1 (2007): 43-49. Web . Hamabe , L. et al. 'Echocardiographic Evaluation Of Myocardial Changes Observed After Closure Of Patent Ductus Arteriosus In Dogs'.  Journal of Veterinary Internal Medicine  29.1 (2015): 126-131. Web . Israel, N. Van, J. Dukes-McEwan, and A. T. French. 'Long-Term Follow-Up Of Dogs With Patent Ductus Arteriosus '.  Journal of Small Animal Practice  44.11 (2003): 480-490. Web . Stokhof , A. A., N. Sr eeram , and W. Th. C. Wolvekamp . ' Transcatheter Closure Of Patent Ductus Arteriosus Using Occluding Spring Coils'.  J Vet Int Med  14.4 (2000): 452. Web . Buchanan, James W., and Donald F. Patterson. ' Etiology Of Patent Ductus Arteriosus In Dogs'.  J Vet Int Med  17.2 (2003): 167. Web . Hogan, Daniel F. et al. ' Transarterial Coil Embolization Of Patent Ductus Arteriosus In Small Dogs With 0.025-Inch Vascular Occlusion Coils: 10 Cases'.  Journal of Veterinary Internal Medicine  18.3 (2004): 325-329. Web . Luis Fuentes, Virginia, Lynelle R Johnson, and Simon Dennis.  BSAVA Manual Of Canine And Feline Cardiorespiratory Medicine . Quedgeley : British Small Animal Veterinary Association, 2010. Print . Brockman, Daniel J, and David E Holt.  BSAVA Manual Of Canine And Feline Head, Neck And Thoracic Surgery . Quedgeley , Gloucester: British Small Animal Veterinary Association, 2005. Print.