Non-cardiogenic pulmonary oedema complicating balloon valvuloplasty and stent angioplasty of severe pulmonary valve stenosis in four dogs

In dogs, balloon valvuloplasty is considered the treatment of choice for severe pulmonary valve stenosis, and this technique is currently performed routinely in specialist referral practices with low morbidity and mortality. Stent angioplasty has also been recently proposed as a viable treatment option. The present case series describes the clinical course of four dogs with severe pulmonary valve stenosis, treated with balloon valvuloplasty or stent angioplasty at four different institutions, which developed non-cardiogenic pulmonary oedema perioperatively after apparently successful dilation of the pulmonary valve. In three cases, there was evidence of some degree of pulmonary hypertension before ballooning. Despite intensive care, the complication proved fatal in three cases. Clinicians should therefore be aware of this life-threatening complication, previously undescribed in dogs.     

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.     

Assessment of balloon pulmonary valvuloplasty in six dogs

The effectiveness of balloon valvuloplasty was assessed, clinically and haemodynamically, in six dogs with moderate to severe pulmonic stenosis. The haemodynamic assessment was based on Doppler echocardiography, with colour flow mapping, in the conscious dog and by direct catheterisation in the anaesthetised dog, before and after balloon valve dilatation. Four of the six dogs were presented with exercise intolerance, of which two were in congestive heart failure. Balloon valvuloplasty resulted in improved exercise tolerance and resolution of congestive heart failure in these dogs. The average Doppler and catheter transvalvular pressure gradients were reduced to 43 per cent and 46 per cent of the preoperative gradient, respectively. The average pressure gradient obtained by catheter, in the anaesthetised dog, was 59 per cent of the pressure gradient obtained by spectral Doppler echocardiography in the conscious dog. Balloon valvuloplasty was considered successful in five out of the six dogs. Postoperative pulmonic regurgitation was not found to be a complication of balloon valvuloplasty.     

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.     

Fatal acute lung injury after balloon valvuloplasty in a dog with pulmonary stenosis

A one-year-old French Bulldog was referred for the management of a severe form of pulmonary valve stenosis (PS) complicated by right-sided congestive heart failure.Echocardiography showed severe valvular PS with right ventricular concentric hypertrophy, dilatation and severe right atrial enlargement. A pulmonary balloon valvuloplasty (PBV) was performed with a balloon-to-pulmonary annulus ratio of 1.36. Echocardiography immediately after PBV showed a significant reduction in right atrial and ventricular size, improved opening and mobility of the pulmonary valve leaflets, and a 75% reduction in the pulmonary pressure gradient from 158 mmHg pre-operative to 40 mmHg post-operative. The dog recovered well from anesthesia, but 2 h later, it suddenly showed severe respiratory distress. Focus cardiac ultrasound showed increased left cardiac size with echocardiographic signs of high left ventricular filling pressure. Bedside lung ultrasound showed diffuse numerous-to-confluent B lines, compatible with a severe alveolar-interstitial syndrome. The dog was treated with furosemide, helmet continuous positive airway pressure, and then mechanical ventilation but without success.At post-mortem evaluation, histological examination of the lung showed diffuse, severe broncho-alveolar edema with mixed leukocyte, fibrin, and red blood cell infiltrate. Moreover, severe congestion and multifocal alveolar hemorrhages were evident. All findings were compatible with fatal acute lung injury after PBV secondary to pulmonary reperfusion-ischemia injury and increased pulmonary capillary hydrostatic pressure. Based on the present case, acute lung injury should be considered as a rare but serious complication of PBV.     

Combined interventional procedure and cardiopulmonary bypass surgery in a dog with cor triatriatum dexter,patent foramen ovale,and pulmonary stenosis

A 2‐year‐old American Pit Bull dog was presented for surgical evaluation of imperforate cor triatriatum dexter (CTD) and patent foramen ovale (PFO). Echocardiography identified an imperforate CTD associated with a right‐to‐left shunting PFO and valvular pulmonary stenosis. A 2‐step interventional and surgical approach was used. Initially, a pulmonary balloon valvuloplasty was performed, and subsequently the dog underwent a surgical correction of the atrial anomaly under cardiopulmonary bypass.     

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.     

Restenosis after balloon valvuloplasty in a dog with pulmonary stenosis

A two-month-old female Chihuahua was diagnosed as severe pulmonary valvular stenosis (PS). Although balloon valvuloplasty (BV) was successfully performed, restenosis was observed 19 months after the procedure. Euthanasia was chosen due to low output syndrome during the surgical repair attempted when the dog was 5 years old. Postmortem examination revealed markedly thickened pulmonary valve due to the increase of extracellular matrix which might be produced by increased α smooth muscle actin-positive myofibroblasts. The thickening of the valve was associated with restriction of the valve’s motion, resulting in restenosis in the present case. This is the first case report documented histopathological and immunohistochemical findings of the restenotic pulmonary valve in dogs with PS after BV.     

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.     

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.     

Persistent left cranial vena cava draining into the left atrium associated with pulmonary stenosis in a French bulldog

A 5-month-old female French bulldog was evaluated for the presence of a heart murmur. Through clinical and echocardiographic evaluations, a severe Type A pulmonary stenosis was diagnosed. Angiography during right ventricular catheterization for valvuloplasty revealed drainage from a persistent left cranial vena cava (PLCVC) into the left atrium; this was confirmed later by contrast echocardiography. This report is the first to describe this anatomical variant of a PLCVC in a dog.     

Stenting of the right ventricular outflow tract in 2 dogs for palliation of dysplastic pulmonary valve stenosis and right-to-left intracardiac shunting defects

Two dogs with severe dysplastic pulmonary valve stenosis and right-to-left shunting defects (patent foramen ovale, perimembranous ventricular septal defect) underwent palliative stenting of the right ventricular outflow tract and pulmonary valve annulus using balloon expandable stents. One dog received 2 over-lapping bare metal stents placed 7 months apart; the other received a single covered stent. Both procedures were considered technically successful with a reduction in the transpulmonary valve pressure gradient from 202 to 90 mmHg in 1 dog and from 168 to 95 mmHg in the other. Clinical signs of exercise intolerance and syncope were temporarily resolved in both dogs. However, progressive right ventricular concentric hypertrophy, recurrent stenosis, and erythrocytosis were observed over the subsequent 6 months leading to poor long-term outcomes. Stenting of the right ventricular outflow tract is feasible in dogs with severe dysplastic pulmonary valve stenosis, though further study and optimization of the procedure is required.     

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.     

Stent angioplasty for treatment of canine valvular pulmonic stenosis

Four dogs presented for evaluation and treatment of severe pulmonic valve stenosis and underwent stenting of the pulmonic valve annulus using bare-metal balloon-expandable stents. All dogs survived the procedure with immediate reduction of the transpulmonary valve pressure gradient and increase in activity levels. One dog had a stent fracture and migration 1 month after the intervention. This dog underwent a second procedure, in which multiple stents were used to alleviate the obstruction. The stents that were placed at the level of the right ventricular outflow tract fractured within 1 month of the procedure, and the patient died when a third (surgical) approach was attempted. The other three dogs remain alive 54, 42, and 29 months after the procedure. Stent angioplasty may be a viable option for dogs with valvular pulmonic stenosis in which routine balloon valvuloplasty does not provide a successful outcome. Aggressive attempts to diminish RVOT dynamic obstruction with high-dose beta blockade and avoiding deployment of the stent within the RVOT are recommended to prevent stent fracture and migration.     

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.     

Percutaneous balloon valvuloplasty in four dogs with pulmonic stenosis

Four young dogs with severe pulmonic stenosis were treated by percutaneous balloon valvuloplasty. Pressure gradients between the right ventricle and pulmonary artery were markedly reduced by the procedure resulting in dramatic improvements in growth rate and clinical condition. No postoperative problems were encountered.     

Percutaneous balloon valvuloplasty for treatment of pulmonic stenosis in a dog

A 2.5-year-old dog with congenital pulmonary valve dysplasia was treated by percutaneous balloon dilation of the stenotic orifice. Clinical and hemodynamic improvement was apparent immediately and for 9 months after the valvuloplasty procedure.     

Balloon valvuloplasty in 30 dogs with pulmonic stenosis: effect of valve morphology and annular size on initial and 1-year outcome

Case records of 30 dogs in which valvular pulmonic stenosis (PS) was treated by balloon dilation were reviewed retrospectively. Physical examination, thoracic radiographs, 9-lead ECG, echocardiography, and Doppler studies were performed in all dogs. Two-dimensional and Doppler echocardiography were repeated after 24 h and 1 year after treatment. Dogs were divided into 2 groups based on their valvular anatomy on echocardiography and aortic:pulmonary ratio: 18 had type A PS with normal annulus diameter and aortic:pulmonary ratio < or = 1.2, and 12 had type B PS with pulmonary annulus hypoplasia and aortic:pulmonary ratio > 1.2. Most dogs in the type B group were brachycephalic and had no poststenotic dilatation on thoracic radiographs. Of the dogs with type A stenosis, 100% survived valvuloplasty with resolution of clinical signs. At 1-year follow-up, 94.4% were still alive and remained asymptomatic. Of those with type B stenosis, 66.6% had favorable outcome postvalvuloplasty. At 1-year follow-up, 66.6% of dogs were alive, and resolution of clinical signs was obtained in 50%. This study revealed the immediate and long-term efficacy of balloon valvuloplasty in dogs with PS.     

Echoguided closed commissurotomy for mitral valve stenosis in a dog

Surgical treatment of mitral stenosis (MS) usually consists of open mitral commissurotomy (MC) or percutaneous balloon MC, which require a cardiopulmonary bypass or transseptal approach, respectively. We describe here the first surgical management of congenital MS in a dog using a less invasive procedure, a surgical closed MC under direct echo guidance. A 5-year-old female Cairn terrier was referred for ascites, weakness, and marked exercise intolerance for 2 months, which was refractory to medical treatment. Diagnosis of severe MS associated with atrial fibrillation (AF) was confirmed by echo-Doppler examination and electrocardiography. Poor response to medical treatment suggested a corrective procedure on the valve was indicated. However, due to the cost and high mortality rate associated with cardiopulmonary bypass, a hybrid MC was recommended. A standard left intercostal thoracotomy was performed and three balloon valvuloplasty catheters of differing diameters were sequentially inserted through the left atrium under direct echo guidance. Transesophageal echocardiography revealed a 62% reduction in the pressure half-time compared to the pre-procedure. Thirteen months after surgery the dog is still doing well with resolution of ascites and a marked improvement of most echo-Doppler variables.