Mike Stafford Johnson

Catheter closure of patent ductus arteriosus in dogs: variation in ductal size requires different techniques.

BACKGROUND : Catheter closure of patent ductus arteriosus Botalli (PDA) is increasingly replacing traditional surgical ligation via thoracotomy. A variety of techniques have been described in dogs, although the technique and implant chosen may depend on the minimum ductus diameter. OBJECTIVES : To evaluate the feasibility and treatment of choice of catheter closure of large and small PDAs in dogs. METHODS : In 16 dogs with a PDA, catheter closure was performed using transarterial embolisation using detachable or free coils, or transvenously using an Amplatzer, duct occluder (ADO). RESULTS : In 8 dogs, closure of PDA with a minimum diameter of < 4 mm was achieved using detachable coils; 2 or more coils were required in 3 dogs. In 5 dogs with minimum ductus diameters of > 4 mm, detachable coils were not applicable. In one of these dogs, (incomplete) surgical ligation was performed and later a free coil placed for complete closure. In 2 dogs with moderately large PDA (5 mm), several free coils were implanted. Complete closure was not achieved in either dog and transient haemolysis occurred as a complication. In 2 dogs with a very large PDA (6 mm), implanted free coils embolised to pulmonary arteries and closure was then achieved using an ADO. In 3 dogs with an excessively large PDA (7.5-10 mm) closure was successfully achieved using an ADO with no complications. CONCLUSIONS : Coil embolisation is readily feasible for closure of PDA < 4 mm, less feasible for PDA < 5 mm and unlikely to be feasible to close PDA > 5 mm. Detachable coils are safe for PDA < 4 mm, and the ADO is an excellent device for PDA > 5 mm.

Outcome in 55 dogs with pulmonic stenosis that did not undergo balloon valvuloplasty or surgery

OBJECTIVE To determine the outcome, independent predictors of cardiac death, and the Doppler-derived pressure gradient cut-off for predicting cardiac death in dogs with pulmonic stenosis, with or without tricuspid regurgitation, that do not undergo balloon valvuloplasty or valve surgery. METHODS Review of medical records of two UK referral centres between July 1997 and October 2008 for all cases of pulmonic stenosis that had no balloon valvuloplasty or valve surgery. Inclusion criteria included a diagnosis of pulmonic stenosis; spectral Doppler pulmonic velocity greater than 1·6 m/s; characteristic valve leaflet morphological abnormalities. Exclusion criteria included concurrent significant cardiac defects, including tricuspid dysplasia. Dogs with tricuspid regurgitation were included. Dogs were classified according to Doppler-derived pressure gradients into mild, moderate or severe pulmonic stenosis categories. RESULTS Presence of tricuspid regurgitation and severe stenosis were independent predictors of cardiac death. A pulmonic pressure gradient of more than 60 mmHg was associated with 86% sensitivity, and 71% specificity of predicting cardiac death. CLINICAL SIGNIFICANCE There is an increased probability of cardiac death in those cases which have a pulmonary pressure gradient greater than 60 mmHg and tricuspid regurgitation, though the effect of severity of tricuspid regurgitation on outcome was not measurable because of small sample sizes. These animals might benefit from intervention.

Investigation of dyspnoea in dogs

DYSPNOEA is a relatively common presentation in dogs and has many possible aetiologies. The initial clinical assessment is essential to help identify the likely origin of the dyspnoea and determine the steps necessary to stabilise the clinical signs. Diagnostic techniques, such as radiography, bronchoscopy and thoracocentesis, can be easily performed in practice and will greatly aid investigation. This article describes the clinical signs of dyspnoea in dogs and outlines the approach to diagnosis in affected animals.

Association of QRS duration and survival in dogs with dilated cardiomyopathy: a retrospective study of 266 clinical cases.

OBJECTIVE The purpose of this study was to investigate the prognostic value of QRS duration in dogs with dilated cardiomyopathy (DCM) by studying its relationship with survival time. METHODS The medical records of dogs diagnosed with DCM were retrospectively searched for good quality ECG tracings. The QRS duration was measured from the ECG tracing and two different models were used: binary variable (dogs were divided into 2 groups based on a QRS duration of <60 ms or ≥60 ms) and continuous variable. The survival times were analysed by the Kaplan-Meier method and Coxs proportional hazard model. RESULTS 266 dogs met the inclusion and exclusion criteria. A QRS duration ≥60 ms was associated with a reduced survival time compared to those with a QRS duration <60 ms (Hazard Ratio of 1.34, 95% CI 1.05-1.71, P = 0.02). When considered as a continuous variable the Hazard Ratio was 1.015 for each increase in QRS duration of 1 ms (95% CI 1.006-1.024, p = 0.001).Dogs with a QRS duration < 60 ms had a median survival time (IQ range) of 25 weeks (97-65) and dogs with a QRS duration ≥60 ms had a median survival time (IQ range) of 13 weeks (3-34). CONCLUSION The measurement of QRS duration is relatively simple to perform from a surface ECG recording. A duration ≥60 ms is associated with shorter survival times in dogs with DCM, which may provide practitioners with additional prognostic information.

Assessing dogs and cats with heart disease

Mark A. Oyama, Marc S. Kraus and Anna R. Gelzer 96 pages, paperback, £24.99. CRC Press. 2013. ISBN 978 1 84076 198 6 ![Graphic][1] THIS purports to be a concise and practical guide to ECG interpretation for general practitioners and veterinary students. A more succinct or more practical guide would be difficult to find. The authors are all hands-on clinicians and they very much emphasise the practical rather than the theoretical aspects of electrocardiography. Four sections are included in the book. Section 1 covers principles of … [1]: /embed/inline-graphic-1.gif

An update on transcatheter occlusion of patent ductis arteriosus in dogs

A patent ductus arteriosus, PDA, is one of the most common congenital cardiac defects in dogs. Previously a variety of methods was used to repair a PDA. These methods have now largely been superseded by the use of the relatively new Canine Amplatz Duct Occluder. This article details the advantages of the new device – these include increased ease of repair, reduced length of procedure and reduced incidence of residual flow through the ductus after repair.