Results of balloon valvuloplasty in 40 dogs with pulmonic stenosis

The records of 43 dogs presenting with severe pulmonic stenosis in which balloon valvuloplasty was attempted were reviewed. Thirty-four dogs (79 per cent) were symptomatic at initial presentation. All patients were selected for balloon valvuloplasty on the basis of a Doppler-derived trans-stenotic pressure gradient of over 80 mmHg and concurrent evidence of mild to severe right ventricular hypertrophy. Forty dogs underwent balloon valvuloplasty; the procedure was not performed in three dogs because of an aberrant coronary artery in two cases and because catheterisation of the pulmonary artery was not possible in the third. Overall, 37 out of the 40 dogs (93 per cent) were successfully ballooned, resulting in a mean reduction in the pressure gradient of 46 per cent, with a mean pressure gradient of 124 mmHg on presentation and 67 mmHg six months after the procedure. Three dogs died during balloon valvuloplasty (all of which had a concurrent defect) and three dogs showed a poor clinical response to the procedure. Thus balloon valvuloplasty was successful and resulted in a sustained clinical improvement in 80 per cent of previously symptomatic cases. This study was undertaken to document the results of balloon valvuloplasty in a larger population of dogs than has previously been published.     

Treatment of Congenital Pulmonic Stenosis in Two Dogs by Balloon Valvuloplasty

Balloon valvuloplasty was performed on two dogs with pulmonic valve stenosis. Immediately following balloon valvuloplasty, peak right ventricular systolic pressure declined from 92 to 44 mm Hg in the first dog and from 108 to 46 mm Hg in the second dog. The peak systolic pressure gradient across the pulmonic valve declined from 60 to 12 mm Hg in the first dog and from 84 to 22 mm Hg in the second dog. Hemodynamic improvement was sustained in both dogs at the time of recatheterization 3 months later. Both dogs tolerated the procedure well and there were no serious complications. It was concluded that balloon valvuloplasty offers an alternative to surgery for the treatment of valvular pulmonic stenosis in dogs. The exact indications for and limitations of balloon valvuloplasty must await the results of additional and more long-term studies.     

Evaluation of closed pericardial patch grafting for management of severe pulmonic stenosis

Closed pericardial patch-grafting has been advocated for the treatment of severe pulmonic stenosis. In this study pre- and postoperative echocardiography was used to determine if the transvalvular pressure gradient was successfully lowered by this surgery and whether it remained lowered long term. The valvulotomy-ventriculectomy wire was passed using a blunt needle in four dogs (Bresnock technique1) and via a soft catheter in five dogs (Shores and Weirich modification). Eight of nine patients survived the perioperative period. These dogs were assessed up to 40 months following surgery for clinical and echocardiographic changes. Five cases showed significant decrease in peak pulmonic pressure gradient immediately after surgery (decreasing by 50-81%, P < 0.05), and six cases showed significant decrease 2 to 40 months postoperatively (decreasing by 31-80%, P < 0.005) when compared to preoperative values. There was no significant change in pulmonic pressure gradient from immediately postoperatively to 2 to 40 months postoperatively (P < 0.48). Six dogs showed clinical improvement postoperatively, however persistent right ventricular hypertrophy was observed in all cases. One dog died with symptoms of congestive heart failure 16 months postoperatively. Closed pericardial patch grafting can improve clinical signs in symptomatic patients, however the surgery has significant risks, long term prognosis for these patients is guarded and recurrence of clinical signs and development of congestive heart failure is possible. Cardiac changes can be monitored with Doppler flow echocardiography. Patients with extremely elevated preoperative pressure gradients may be expected to have poorer outcomes.     

Pulmonary artery dissection following pulmonary balloon valvuloplasty in dogs

Introduction/objectivesPulmonary artery dissection is a rare complication following balloon valvuloplasty for pulmonic stenosis. We sought to report the rate of this complication in dogs and describe the demographic, clinical, procedural, and outcome data in affected dogs.Animals, materials and methodsMedical records at a single academic institution between 2002 and 2021 were reviewed for dogs with pulmonic stenosis treated by a balloon valvuloplasty. Dogs were included for evaluation if there was evidence of pulmonary artery dissection on echocardiography or necropsy following balloon valvuloplasty. The demographic, clinical, surgical, and follow-up information were then recorded.ResultsSix dogs were included from 210 balloon valvuloplasty procedures for pulmonic stenosis giving a 3.9% rate of pulmonary dissection. There was a variety of signalment, pulmonary valve morphologies, and balloon catheter types used in each dog. All dogs had severe pulmonic stenosis (median pressure gradient of 208 mmHg, range 94–220 mmHg) with 5/6 dogs having a pressure gradient >144 mmHg. The median balloon to pulmonary valve annulus ratio was 1.35 (range 1.25–1.5). Three dogs died perioperatively, and three dogs were alive at follow up 3.3, 4.0, and 4.1 years postoperatively.ConclusionPulmonary artery dissection is a rare complication following balloon valvuloplasty for pulmonic stenosis. Extreme elevations in preoperative pulmonary valve flow velocity were common. Prognosis is variable, with a potential 50% perioperative survival rate, but extended survival times were noted in those patients discharged from hospital.     

Balloon Valvuloplasty for Treatment of Pulmonic Stenosis in English Bulldogs with an Aberrant Coronary Artery

Background: English Bulldogs (EB) with pulmonic stenosis (PS) sometimes have an aberrant coronary artery (CA) type R2A encircling the pulmonary artery (PA). Balloon valvuloplasty (BV) is treatment of choice for severe PS, but is considered to be contraindicated in dogs with aberrant CA. Hypothesis: Conservative BV in EB with aberrant CA is safe and improves clinical signs and quality of life. Animals: Four client‐owned EB with severe PS were retrospectively reviewed/analysed. Methods: Retrospective study: Case records, echocardiography, BV, and follow‐up investigations of EB diagnosed with severe PS and treated with BV were reviewed. The ratios of PA to aortic (Ao) velocity time integral (VTI) were calculated to assess progression/improvement of PS. Results: An aberrant CA was confirmed on angiography in all EB. Conservative BV was performed, using a balloon of the size of the PA annulus or smaller (0.6–1 × PA annulus size). All dogs survived the procedure, but only a mild reduction in pressure gradient was achieved. There was an improvement in PA to Ao VTI in 3 of 4 dogs (P≤ .017), which were free of evidence of congestive heart failure (CHF) 5, 10, and 15 months after BV. One dog that had right‐sided CHF when BV was performed died due to progressive right‐sided CHF within 3 months. Conclusions: Conservative BV in EB might be safe and might improve quality and quantity of life.     

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.     

Balloon dilation of right ventricular outflow tract in a dog with tetralogy of Fallot.

Balloon dilation was performed on a dog with tetralogy of Fallot. Immediately following balloon dilation, the peak systolic pressure gradient across the pulmonic valve declined from 97 to 63 mmHg. Doppler echocardiography following balloon dilation revealed increased pulmonary blood flow. Clinical symptoms obviously improved and the dog's improved condition was maintained for 4 months. There were no serious complications in performing the procedure. It was concluded that balloon dilation was a safe and effective treatment for a dog case with tetralogy of Fallot. Long-term follow-up studies will be required to identify the exact indications of balloon dilation for tetralogy of Fallot.     

Balloon valvuloplasty of congenital mitral stenosis

Radiographic, echocardiographic, fluoroscopic, and angiographic images from 2 dogs with severe congenital mitral valve stenosis that underwent cardiac catheterization and balloon valvuloplasty are presented. Both dogs displayed systolic doming of the mitral valve leaflets, increased diastolic pressure gradient across the left atrium and ventricle, and decreased mitral inflow E to F slope. Balloon valvuloplasty was performed on both dogs using atrial transeptal puncture.     

Primary pulmonic infundibular stenosis in 12 cats: Natural history and the effects of balloon valvuloplasty

ObjectivesTo evaluate the natural history of primary pulmonic infundibular stenosis in cats and the effects of balloon valvuloplasty.BackgroundPrimary pulmonic infundibular stenosis is an uncommon congenital defect in cats. The natural history of the disease has not been described. Information regarding balloon valvuloplasty in the cat is limited.AnimalsRecords between January 1, 1999 and December 31, 2005 were reviewed and cats with a confirmed echocardiographic diagnosis of primary pulmonic infundibular stenosis, a complete medical history, and no evidence of significant systemic disease were identified.MethodsEchocardiographic, electrocardiographic, and radiographic findings are described. The natural history of those with severe disease was compared to those with mild to moderate disease. Balloon valvuloplasty was performed in six of the cats. The technique used is described.ResultsA stenotic gradient ≥70 mmHg and a right ventricular outflow tract (measured at the level of the stenosis) to pulmonary valve annulus ratio of ≤0.25 were consistent with clinical and echocardiographic severe disease. Cats with severe disease had a very guarded prognosis with a high incidence of congestive heart failure (CHF). Balloon valvuloplasty was successfully performed in 4 of the cats and appeared to improve prognosis, especially if performed prior to the development of CHF. Concurrent hypertrophic cardiomyopathy complicated the outcome in some cats.ConclusionsSevere primary pulmonic infundibular stenosis carries a very guarded prognosis in the cat. Balloon valvuloplasty should be considered in the presence of severe disease and should be performed prior to the development of CHF if possible. The presence of concurrent hypertrophic cardiomyopathy may complicate the prognosis.     

How to perform combined cutting balloon and high pressure balloon valvuloplasty for dogs with subaortic stenosis

Subvalvular aortic stenosis (SAS) is one of the most common congenital cardiac malformations in dogs. Unfortunately, the long term success rate and survival data following either open heart surgery or catheter based intervention has been disappointing in dogs with severe subaortic stenosis. Medical therapy is currently the only standard recommended treatment option. A cutting balloon dilation catheter has been used successfully for resistant coronary artery and peripheral pulmonary arterial stenoses in humans. This catheter is unique in that it has the ability to cut, or score, the stenotic region prior to balloon dilatation of the stenosis. The use of cutting balloon valvuloplasty combined with high pressure valvuloplasty for dogs with severe subaortic stenosis has recently been reported to be a safe and feasible alternative therapeutic option. The following report describes this technique, outlines the materials required, and provides some ‘tips’ for successful percutaneous subaortic balloon valvuloplasty.     

Survival times in dogs with severe subvalvular aortic stenosis treated with balloon valvuloplasty or atenolol

OBJECTIVE: To determine survival times in dogs with severe subvalvular aortic stenosis (SAS) treated by means of balloon valvuloplasty or with atenolol, a beta-adrenoceptor blocking drug. DESIGN: Prospective study. ANIMALS: 38 dogs < 24 months old with severe SAS (peak systolic pressure gradient > or = 80 mm Hg). PROCEDURE: 10 dogs underwent balloon valvuloplasty and were reexamined 6 weeks later to determine the feasibility of the procedure. The remaining 28 dogs were randomly assigned to undergo balloon valvuloplasty (n = 15) or to be treated with atenolol long term (13) and were reexamined annually for 9 years or until the time of death. RESULTS: For the first 10 dogs, mean pressure gradient 6 weeks after balloon valvuloplasty (mean +/- SD, 119 +/- 32.6 mm Hg) was significantly decreased, compared with mean baseline pressure gradient (167 +/- 40.1 mm Hg). Median survival time for dogs that underwent balloon valvuloplasty (55 months) was not significantly different from median survival time for dogs treated with atenolol (56 months). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that balloon valvuloplasty can result in a significant decrease in the peak systolic pressure gradient in dogs with severe SAS, at least for the short term. No clear benefit in survival times was seen for dogs that underwent balloon valvuloplasty versus dogs that were treated with atenolol.     

Percutaneous catheter-based treatment of pulmonic stenosis and patent ductus arteriosus in a dog

A 6-months old female German shepherd dog was referred for management of congenital heart disease. A diagnosis of pulmonic stenosis (PS) and patent ductus arteriosus (PDA) was confirmed by Doppler echocardiography and cardiac catheterisation. The conditions were treated during a single cardiac catheterisation procedure using percutaneous techniques. Gianturco coil embolisation was used to close the PDA, and the PS was relieved using a balloon valvuloplasty technique.     

Cutting balloon and high-pressure balloon dilation for palliative treatment of congenital double-chambered right ventricle and primary infundibular stenosis in a Golden retriever dog

Combined cutting balloon and high-pressure balloon dilation was performed in a dog with a double-chambered right ventricle and severe infundibular stenosis of the right ventricular outflow tract. The peak systolic pressure gradient across the stenosis decreased by 65% after dilation (from 187 mmHg before to 66 mmHg after) affirming the intervention as successful. However, early re-stenosis occurred within 3 months leading to exercise intolerance, exercise-induced syncope, and right-sided congestive heart failure. Cutting balloon followed by high-pressure balloon dilation provided temporary but not long-term relief of right ventricular obstruction in this dog.     

Mitral Stenosis in 15 Dogs

Mitral stenosis was diagnosed in 15 young to middle-aged dogs. There were 5 Newfoundlands and 4 bull terriers affected, suggesting a breed predisposition for this disorder. Clinical signs included cough, dyspnea, exercise intolerance, and syncope. Soft left apical diastolic murmurs were heard only in 4 dogs, whereas 8 dogs had systolic murmurs characteristic of mitral regurgitation. Left atrial enlargement was the most prominent radiographic feature. Left-sided congestive heart failure was detected by radiographs in 11 dogs within 1 year of diagnosis. Electrocardiographic abnormalities varied among dogs and included atrial and ventricular enlargement, as well as atrial and ventricular arrhythmias. Abnormalities on M-mode and two-dimensional echocardiograms included abnormal diastolic motion of the mitral valve characterized by decreased leaflet separation, valve doming, concordant motion of the parietal mitral valve leaflet, and a decreased E-to-F slope. Increased mitral valve inflow velocities and prolonged pressure half-times were detected by Doppler echocardiography. Cardiac catheterization, performed in 8 dogs, documented a diastolic pressure gradient between the left atrial, pulmonary capillary wedge, or pulmonary artery diastolic pressures and the left ventricular diastolic pressure. Necropsy showed mitral stenosis caused by thickened, fused mitral valve leaflets in 5 dogs and a supramitral ring in another dog. The outcome in affected dogs was poor; 9 of 15 dogs were euthanatized or died by 2 1/2 years of age.     

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

OBJECTIVE: To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation. PROCEDURE: Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs. RESULTS: Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001). CONCLUSION: It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.     

Acute pulmonary edema in a dog with severe pulmonary valve stenosis: A rare complication after balloon valvuloplasty

Pulmonic stenosis is a frequent congenital heart disease in dogs, and the treatment of choice is balloon valvuloplasty which is usually safe and successful. The authors describe for the first time a severe complication after balloon valvuloplasty in a five-month-old dog. After effective treatment, with a considerable drop in right ventricular pressures, the dog developed hypoxemia and dyspnea due to pulmonary edema. The dog underwent intensive care and symptoms improved after a few hours of oxygen therapy, continuous positive airway pressure, and furosemide. Although this event is rare, it could have a large impact on patient survival and should be considered in the treatment of severe pulmonary valve stenosis in the future.     

Non‐electrocardiographic‐gated computed tomographic angiography can be used to diagnose coronary artery anomalies in Bulldogs with pulmonary valve stenosis

Coronary artery anomalies have been reported in Bulldogs and present an increased risk when performing balloon valvuloplasty. Identification of coronary anomalies has been reported using multidetector‐row computed tomographic (MDCT) angiography with electrocardiographic gating. However, the utility of non‐electrocardiographic‐gated 16‐row computed tomographic for MDCT for the identification of coronary artery anatomy or anomalies to the authors’ knowledge has not been fully investigated. The purpose of this study was to evaluate the feasibility of non‐electrocardiographic‐gated computed tomographic (CT) angiography to identify coronary anomalies in Bulldogs with pulmonary valve stenosis. In this prospective, observational study, Bulldogs with echocardiographically diagnosed pulmonary valve stenosis, an echocardiographically derived transpulmonic pressure gradient >70 mm Hg, and a clinician recommendation for balloon valvuloplasty were included. Anesthetized dogs underwent a 16‐row MDCT non‐electrocardiographic‐gated CT angiography. A board‐certified veterinary radiologist and board‐certified veterinary cardiologist reviewed the CT angiography studies and identified the coronary artery anatomy. When normal coronary artery anatomy was detected on CT angiography, a right ventricular outflow tract fluoroscopic angiogram was performed and evaluated during levophase to confirm normal coronary anatomy prior to balloon valvuloplasty. Dogs with coronary anomalies noted on CT angiography were recovered from anesthesia and balloon valvuloplasty was not performed. All dogs (10/10; 100%) had interpretable images from the non‐electrocardiographic‐gated CT angiography. Coronary anomalies were identified in six dogs based on non‐electrocardiographic‐gated CT angiography, five with type R2A anomaly and one had a single left coronary ostium. Four dogs had normal coronary anatomy based on non‐electrocardiographic‐gated CT angiography. Balloon valvuloplasty was performed without incident in these four dogs. We conclude that non‐electrocardiographic‐gated CT angiography represents a noninvasive method for diagnosing coronary anomalies in Bulldogs with pulmonary valve stenosis.     

Progression of aortic stenosis in the boxer

Thirty-five boxers that had been referred to the Royal (Dick) School of Veterinary Studies between 1989 and 1994 with left heart base murmurs and aortic velocities greater than 1.5 m/second on Doppler echocardiography were recalled for clinical examination and Doppler echocardiography between 1995 and 1996. Five dogs (14 per cent) showed an increase in murmur grade on repeat visit. Six dogs (17 per cent) showed an increase in aortic velocity of greater than 20 per cent. Eight dogs (23 per cent) had developed aortic valvular or subvalvular two-dimensional echocardiographic changes that had not been present at the initial visit. Seven dogs (20 per cent) had developed aortic regurgitation, and three dogs (8 per cent) mitral regurgitation.     

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

Objective To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation.
Procedure Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs.
Results Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocar-diography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001).
Conclusion It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.     

Balloon valvuloplasty for palliative treatment of tricuspid stenosis with right-to-left atrial-level shunting in a dog

A 3.75-year-old castrated male Chesapeake Bay Retriever was referred for evaluation of tachypnea, exercise intolerance, and cyanosis. Echocardiographically, there was severe tricuspid stenosis and right-to-left atrial-level shunting of blood. Marked compensatory polycythemia had developed; the PCV was 75%. Balloon dilation of the tricuspid stenosis was performed. Subsequent echocardiographic examinations demonstrated a reduction in the pressure gradient across the tricuspid valve. The PCV returned to the reference range, and the dog's clinical status improved during the 12 months after the procedure. Tricuspid stenosis is an uncommon lesion in dogs and, in the dog of this report, was assumed to have resulted from tricuspid dysplasia. Cyanosis was a result of right-to-left shunting of blood. Limited treatment is available for dogs with cyanotic heart disease. In this dog, balloon dilation of the stenotic tricuspid valve was palliative.