Hybrid balloon valvuloplasty for management of severe mitral stenosis in four symptomatic,adult dogs

Four adult dogs weighing <10 kg presented for the evaluation of severe mitral valve stenosis with clinical signs. Owing to the size of the dogs, a hybrid surgical and interventional approach was utilized for balloon valvuloplasty. A left lateral thoracotomy was performed to allow direct entry through the left atrial wall. Transesophageal echocardiography was utilized for the entirety of the procedure in all dogs, and fluoroscopy was additionally used in two dogs. One dog had mild to moderate intra-operative bleeding from the left atrial wall during the procedure, but no other intra-operative complications were observed. No dogs developed a clinically relevant amount of worsened mitral regurgitation. Based on mitral leaflet mobility and transmitral flow profiles, there was perceived improvement in all four dogs. One dog died 6 h after extubation due to respiratory arrest. The remaining dogs survived to discharge and had resolution of clinical signs at home and discontinuation of heart failure medications. One dog died of an unknown cause at five months and another developed atrial fibrillation, and the owners elected to euthanize at ten months after the procedure. One dog continues to do well six months after the procedure as of the time of this writing. Hybrid balloon valvuloplasty can be a viable management option for small breed dogs with severe mitral stenosis exhibiting clinical signs, and both transesophageal echocardiography and fluoroscopy can be used intra-operatively to assist in successful procedural outcomes.     

Cardiac troponin I and C-reactive protein concentrations in dogs with severe pulmonic stenosis before and after balloon valvuloplasty

Objective

To report cardiac troponin I (cTnI) and C-reactive protein (CRP) concentrations in dogs with severe pulmonic stenosis (PS) before and after balloon valvuloplasty (BV).

Background

Increased morbidity and mortality have been reported with severe PS and histopathologic evidence of myocardial damage is demonstrated with BV. Severity of myocardial injury and inflammation associated with severe PS and BV, as assessed by cTnI and CRP, is unknown.

Animals, materials and methods

Serum cTnI and CRP concentrations were measured in dogs with severe PS (n = 23) and following BV (n = 16).

Results

Baseline cTnI and CRP were elevated in 7/23 (30.4%) and 8/23 (34.8%) dogs. Median cTnI at baseline and post-BV were 0.20 ng/mL (range, 0.20-1.29 ng/mL) and 2.85 ng/mL (range, 0.21-55.40 ng/mL), respectively. Median CRP at baseline and post-BV were 3.40 μg/mL (range, 0-14.70 μg/mL) and 11.70 μg/mL (range, 4.20-120 μg/mL), respectively. Post-BV concentrations were significantly increased compared to baseline for cTnI (p < 0.001) and CRP (p = 0.001).

Conclusions

Serum cTnI and CRP are increased in dogs with severe PS and following BV. Future studies should evaluate whether biomarkers correlate with severity and prognosis of PS or can be used to guide therapy.     

Utility of Transesophageal Echocardiography for Transcatheter Occlusion of Patent Ductus Arteriosus in Dogs: Influence on the Decision‐Making Process

Background: Appropriate device selection for transcatheter occlusion of patent ductus arteriosus (PDA) is essential to procedural success. Objectives: To determine if transesophageal echocardiography (TEE) influences device selection for PDA occlusion and to report benefits, limitations, and complications associated with TEE. Animals: Twenty‐two client‐owned dogs with left‐to‐right shunting PDA. Methods: PDA dimensions were obtained via transthoracic echocardiography (TTE) and then TEE followed by angiography. Based solely on information from TTE and angiography, an initial device type and size were selected. After initial device selection, TEE measurements were disclosed and changes in device selection were recorded. After device release, angiography, TEE, or both were performed to assess occlusion. Results: An Amplatz canine duct occluder (ACDO) was securely positioned and released in 21 dogs and an embolization coil was deployed in 1 dog. Based on TEE evaluation, initial selected device type was unchanged but ACDO size was changed in 3 dogs. TEE was utilized throughout the procedure allowing real time visualization of device deployment, release and assessment of closure in 17 dogs. No complications occurred related to TEE. Complete PDA closure was achieved in all dogs. Conclusions and Clinical Importance: TEE provided anatomic information regarding PDA morphology that closely approximated angiographic ductal dimensions while aiding in device deployment, release and confirmation of closure. We conclude that TEE provides complementary anatomical and intraprocedural information and is well tolerated in dogs.     

Transvenous correction of patent ductus arteriosus in two toy-breed dogs with the Amplatzer™ Vascular Plug 4

Two Pomeranian dogs referred for interventional correction of a left-to-right shunting patent ductus arteriosus (PDA) had inadequate femoral arterial access for any occlusion device other than micro coils. The decision was made to attempt correction of the PDA using the Amplatzer™ Vascular Plug 4 (AVP4) from a femoral venous approach. An AVP4 was successfully deployed in each dog with complete occlusion noted within 5 min. Complete occlusion was persistent at 24 h after the procedure, while both dogs were subclinical, had no residual ductal flow, and complete or near complete reverse cardiac remodeling at subsequent visits. This report demonstrates the feasibility of PDA occlusion with the AVP4 from the femoral venous approach in small dogs where femoral arterial access is inadequate for other occlusion devices.     

Delayed embolization of an Amplatz® canine duct occluder in a dog

A 5-year old, 5.8 kg, castrated male Pomeranian was diagnosed with a type IIa patent ductus arteriosus (PDA) with a minimal ductal diameter of 3.5 mm and ampulla width of 7.1 mm based on angiographic assessment. A 6 mm Amplatz^® Canine Duct Occluder (ACDO) was deployed within the PDA. Once deployed, the device assumed it's native shape and back-and-forth maneuvering was performed with the delivery cable to assess device stability. Device position and complete occlusion were confirmed with both angiography and transesophageal echocardiography prior to and after release of the device. The device location was confirmed within the ductus arteriosus by echocardiography prior to discharge. The dog was discharged with instructions for strict activity restriction. Two days after discharge, the dog was left unsupervised in the backyard and shortly afterwards was found coughing with severe respiratory distress. The dog was evaluated at an emergency hospital and thoracic radiographs documented embolization of the ACDO to the main pulmonary artery along with a severe alveolar pattern throughout the right lung fields. Shortly after obtaining thoracic radiographs, the dog experienced cardiopulmonary arrest with unsuccessful resuscitation. This case describes a possible complication of transcatheter PDA occlusion with an ACDO, which has not been previously reported. An incident report, or catalog of adverse events with these devices, may prove useful in identifying additional fatal complications that others may have encountered, but are not reported in the literature. The report of this complication emphasizes the importance of strict activity restriction after device placement in dogs.     

Long‐Term Outcome in Dogs with Patent Ductus Arteriosus: 520 Cases (1994–2009)

Background

Published information regarding survival and long‐term cardiac remodeling after patent ductus arteriosus (PDA) closure in dogs is limited.

Objectives

To report outcome and identify prognostic variables in dogs with PDA, and to identify risk factors for persistent remodeling in dogs with a minimum of 12 months of follow‐up after closure.

Animals

Five hundred and twenty client‐owned dogs.

Methods

Retrospective review of medical records of 520 dogs with PDA. Outcome was determined by contacting owners and veterinarians. Dogs with PDA closure and ≥ 12 months of follow‐up were asked to return for a re‐evaluation.

Results

In multivariable analysis of 506 dogs not euthanized at the time of diagnosis, not having a PDA closure procedure negatively affected survival (HzR = 16.9, P < .001). In 444 dogs undergoing successful PDA closure, clinical signs at presentation (HzR = 17, P = .02), concurrent congenital heart disease (HD) (HzR = 4.8, P = .038), and severe mitral regurgitation (MR) documented within 24 hours of closure (HzR = 4.5, P = .028) negatively affected survival. Seventy‐one dogs with ≥ 12 months follow‐up demonstrated a significant reduction in radiographic and echocardiographic measures of heart size (P = 0) and increased incidence of acquired HD (P = .001) at re‐evaluation. Dogs with increased left ventricular size and low fractional shortening at baseline were more likely to have persistent remodeling at re‐evaluation.

Conclusions and Clinical Importance

Patent ductus arteriosus closure confers important survival benefits and results in long‐term reverse remodeling in most dogs. Clinical signs at presentation, concurrent congenital HD, and severe MR negatively affect survival. Increased left ventricular systolic dimensions and systolic dysfunction at baseline correlated significantly with persistent remodeling.     

Pre-procedural femoral vessel ultrasound in dogs with patent ductus arteriosus: diameter,image quality and relationship with arterial catheterization

IntroductionObjectives: Patent ductus arteriosus (PDA) in dogs is often treated via minimally invasive transvascular occlusion using femoral artery access. This study compared ultrasound-derived diameter and image quality of the right femoral artery (RFA) and vein (RFV) in dogs with PDA using a linear ultrasound probe (L-P) and phased-array transthoracic echocardiography probe (TTE-P). The case outcome was assessed.Animals, materials & methodsForty-five client-owned dogs with PDA were prospectively enrolled. Ultrasound-measured RFA and RFV diameters were obtained on images acquired with both probes pre-operatively and compared using Bland–Altman plots. The image quality of RFA and RFV was scored on L-P and TTE-P images.ResultsComparison of RFA and RFV diameter from L-P versus TTE-P images revealed: [Mean difference (limits of agreement): RFA = 0.009 mm (−0.78–0.79 mm), RFV = 0.523 mm (−1.75–2.79 mm)]. Image quality scores were significantly higher for L-P than TTE-P (P < 0.0001). In six small dogs, measurable images were unattainable with TTE-P. Dogs of similar body weight had variable RFA diameters. Twenty-seven dogs had RFA catheterization. In 21/27 dogs, RFA diameter exceeded the external diameter of the introducer used for catheterization, and in 6/27, it was smaller.ConclusionsPre-procedural ultrasound of the RFA in dogs with PDA is useful given variable RFA diameter relative to body weight. Despite poorer image quality, RFA diameters from TTE-P images were very similar to L-P images on average, suggesting TTE-Ps are suitable for pre-procedural planning in most dogs. Vasospasm, hypotension or differences in the location of ultrasound measurement versus catheterization might produce variation in pre-procedural versus intraoperative RFA size.     

Transthoracic echocardiographic measurement of patent ductus arteriosus in dogs

BACKGROUND: Patent ductus arteriosus (PDA) size and morphology influence the selection of the kind and the size of the embolization device used to effect shunt closure. HYPOTHESIS: That echocardiographic measurement of PDA in dogs is accurate. ANIMALS: Forty-five client-owned dogs with PDA. METHODS: Prospective observational study. Echocardiographic and angiographic data were compared. RESULTS: Measurement of the ductus in color Doppler echocardiography (CD-E) and 2-dimensional echocardiography (2D-E) was achieved from left parasternal views in 43 of 45 unsedated dogs (96%). In these 43 dogs, the angiographic minimal PDA diameter was 3.72 +/- 1.59 mm, and the diameter of the PDA ampulla was 8.46 +/- 3.01 mm. The CD-E minimal PDA diameter ranged from 2.3 to 9.5 mm (median, 4.0 mm). There was a significant mean difference to the angiographic measurements (1.15 +/- 0.95 mm; P < .0001). An agreement in a 1-mm range was found in 21 of 43 dogs (48%). The 2D-E minimal PDA diameter was 3.73 +/- 1.78 mm, and the mean difference to the angiographic measurements was not significant (0.00 +/- 0.72 mm; P = .98). An agreement in a 1-mm range was found in 31 of 43 dogs (72%). The 2D-E measurement of the PDA ampulla revealed a significant mean difference to the angiographic data (1.95 +/- 2.43 mm, P < .0001). An agreement in a 2-mm range was found in 21 of 43 dogs (49%). CONCLUSIONS AND CLINICAL IMPORTANCE: The 2D-E from the left cranial parasternal view is an excellent noninvasive method to estimate the PDA minimal diameter before doing catheter intervention.     

Real-time 3D transesophageal echocardiography-guided closure of a complicated patent ductus arteriosus in a dog

Advanced imaging modalities are becoming more widely available in veterinary cardiology, including the use of transesophageal echocardiography (TEE) during occlusion of patent ductus arteriosus (PDA) in dogs. The dog in this report had a complex history of attempted ligation and a large PDA that initially precluded device placement thereby limiting the options for PDA closure. Following a second thoracotomy and partial ligation, the morphology of the PDA was altered and device occlusion was an option. Angiographic assessment of the PDA was limited by the presence of hemoclips, and the direction of ductal flow related to the change in anatomy following ligature placement. Intra-operative TEE, in particular real-time three-dimensional imaging, was pivotal for assessing the PDA morphology, monitoring during the procedure, selecting the device size, and confirming device placement. The TEE images increased operator confidence that the size and location of the device were appropriate before release despite the unusual position. This report highlights the benefit of intra-operative TEE, in particular real-time three-dimensional imaging, for successful PDA occlusion in a complicated case.     

Transient high-grade second-degree atrioventricular block secondary to transvenous atrial septal defect occlusion in a dog

A 1.2-year-old male-intact Standard Poodle underwent transvenous placement of an Amplazter™ atrial septal occluder for correction of a large secundum atrial septal defect. Thirty-six hours post-operatively, the dog developed high-grade Mobitz type II second-degree atrioventricular block, which resolved with time and corticosteroid administration by 12 days after the procedure. This case report outlines the observation, treatment, and resolution of high-grade Mobitz type II second-degree atrioventricular block, a known complication of atrial septal occluder placement in humans, not previously reported in veterinary literature.     

Transesophageal Echocardiography as the Sole Guidance for Occlusion of Patent Ductus Arteriosus using a Canine Ductal Occluder in Dogs

Background

Transcatheter occlusion of patent ductus arteriosus (PDA) is usually performed by fluoroscopy alone or together with transesophageal echocardiography (TEE). Transthoracic echocardiography (TTE) guidance has been used for deployment of Amplatz Canine Ductal Occluder (ACDO), but sometimes is limited by suboptimal acoustic windows. Transesophageal echocardiography can overcome such issues and provides higher image resolution at the level of the great vessels.

Objectives

To determine if TEE without fluoroscopy could be used to successfully perform ductal occlusion for the treatment of PDA in dogs.

Animals

Twenty client‐owned dogs with PDA.

Methods

A prospective consecutive case series of PDA occlusion was performed using only TEE guidance. Dogs were positioned in right lateral recumbency and the TEE probe was positioned to visualize the descending aorta, PDA, and pulmonary artery. The guide wire, long introducer sheath, and ACDO were imaged by TEE to direct deployment.

Results

Ductal occlusion was performed successfully without need for fluoroscopy and without complications in 19 dogs. One dog required a second larger ACDO because of embolization of the first device 18 hours after positioning.

Conclusions and Clinical Importance

We have demonstrated that TEE monitoring without concurrent fluoroscopy can guide each step of transcatheter ACDO embolization thereby providing an alternate method of visualization for this procedure. Use of TEE alone can reduce radiation exposure or is an option when fluoroscopy is not available, and, therefore, should be evaluated in a larger case series to better assess procedural failure rates.