Clinical Presentation and Therapy of d-Transposition of the Great Arteries.

d-Transposition of the great arteries (d-TGA) is the most common form of congenital heart disease that presents with cyanosis in a newborn. The aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle. It constitutes 3-5% of all congenital heart defects. In a simple d-TGA (about two-thirds of patients), there is no other cardiac abnormality other than a patent foramen ovale (PFO) and a patent ductus arteriosus (PDA). In a complex d-TGA additional cardiac abnormalities such as VSD, pulmonary stenosis or coronary abnormalities are present. About one-third to 40% of patients with d-TGA have an associated ventricular septal defect. Among patients with d-TGA, 6% of those with intact ventricular septum and 31% of those with ventricular septal defect have associated pulmonary stenosis. Coronary abnormalities are of importance with regard to the complexity of surgical repair.

Balloon pulmonary valvuloplasty: A systematic review.

There is conclusive evidence for relief of pulmonary valve obstruction immediately after balloon pulmonary valvuloplasty (BPV) and at follow-up. Development of infundibular obstruction is seen in more severe PS cases and in older subjects. Reappearance of PS was observed in approximately 10 % of patients following BPV. The reasons for recurrence were found to be balloon/annulus ratio less than 1.2 and immediate post-BPV pulmonary valve peak gradients greater than 30 mmHg. Recurrent stenosis is successfully addressed by repeating BPV with lager balloons than used initially. Long-term results revealed continue relief of obstruction, but with development of pulmonary insufficiency, some patients requiring replacement of the pulmonary valve. It was concluded that BPV is the treatment of choice in the management valvar PS and that balloon/annuls ratio used for BPV should be lowered to 1.2 to 1.25. It was also suggested that strategies should be developed to prevent/reduce pulmonary insufficiency at long-term follow-up.

Pulmonary Valve Stenosis: From Diagnosis to Current Management Techniques and Future Prospects.

Pulmonary stenosis (PS) is mainly a congenital defect that accounts for 7-12% of congenital heart diseases (CHD). It can be isolated or, more frequently, associated with other congenital defects (25-30%) involving anomalies of the pulmonary vascular tree. For the diagnosis of PS an integrated approach with echocardiography, cardiac computed tomography and cardiac magnetic resonance (CMR) is of paramount importance for the planning of the interventional treatment. In recent years, transcatheter approaches for the treatment of PS have increased however, meaning surgery is a possible option for complicated cases with anatomy not suitable for percutaneous treatment. The present review aims to summarize current knowledge regarding diagnosis and treatment of PS.

Non-deflating balloon during pulmonary valvuloplasty.

A 3-year-old, 4.8 kg, male intact, mixed breed dog was referred for balloon pulmonary valvuloplasty (BPV). Echocardiography was consistent with severe type A pulmonic stenosis and BPV was recommended. During BPV, the balloon catheter failed to deflate despite multiple attempts at repositioning and the use of different deflation syringes. After approximately two minutes of cardiopulmonary arrest, forceful retrograde traction resulted in removal of the fully inflated balloon. Cardiopulmonary resuscitation was unsuccessful. Post-mortem evaluation by a board-certified pathologist identified rupture of the cranial vena cava and hemothorax, suspected to be secondary to forceful removal of the fully inflated balloon. Manufacturer's evaluation of the balloon catheter used in the procedure identified multiple kinks and a segment of stretched catheter shaft suspected to be the cause for the inability to deflate. A manufacturing defect present prior to use or predisposing to stretching of the catheter segment could not be ruled out. Kinking and/or stretching of the catheter during BPV were possible causes as well. Although the inability to deflate a balloon catheter seems to be a very rare occurrence, it should be considered as a potential complication of BPV.

Pulmonary artery dissection following pulmonary balloon valvuloplasty in dogs.

INTRODUCTION/OBJECTIVES: Pulmonary 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 METHODS: Medical 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. RESULTS: Six 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. CONCLUSION: Pulmonary 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.

Supravalvular pulmonary stenosis: A risk factor for reintervention in Noonan syndrome with pulmonary valve stenosis.

OBJECTIVES: To assess the short- and long-term outcomes of balloon pulmonary valvuloplasty (BPV) in children with Noonan syndrome (NS). BACKGROUND: Pulmonary stenosis (PS) is the most common congenital heart lesion in NS. BPV is the accepted first line treatment in PS. However, BPV in NS patients has been reported to be less effective, without specific factors for the need for reintervention being identified. METHODS: Retrospective case-note review of all patients with NS who underwent BPV between 1985 and 2020. Patients were divided into 2 groups: those with supravalvular pulmonary stenosis (SPS) in addition to valvar PS, and those with isolated valvar PS. RESULTS: A cohort of 54 patients with NS underwent BPV at a median of 275 (interquartile range [IQR]: 108-575) days of age. SPS was present in 32 (59%) patients whereas 22 had (41) isolated PS. The preprocedural invasive gradient was 47 (IQR: 35-69) mmHg, and 44 (IQR: 35-48) mmHg in those with SPS and those without respectively (p = 0.88). Reintervention was required in 22 patients (41%): 17 (77%) with SPS and 5 (23%) without (p = 0.017). Fourteen patients (11 with SPS) required surgical reintervention and 8 (6 with SPS) required further BPV. There was no significant difference in the age at initial BPV, pre- and postprocedural gradients and interval until reintervention between groups. CONCLUSION: This is the largest reported cohort of patients with NS undergoing BPV. Although BPV is often successful, the reintervention rates are high. SPS was a risk factor for reintervention.

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.

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.

Combined Echo and Fluoroscopy-Guided Pulmonary Valvuloplasty in Neonates and Infants: Efficacy and Safety.

Percutaneous balloon pulmonary valvuloplasty (PBPV) is the treatment of choice for isolated pulmonary valve stenosis. While this procedure is highly efficacious and has an excellent safety profile, as currently practiced, patients are obligatorily exposed to the secondary risks of ionizing radiation and contrast media. To mitigate these risks, we developed a protocol which utilized echo guidance for portions of the procedure which typically require fluoroscopy and/or angiography. Ten cases of echo-guided pulmonary valvuloplasty (EG-PBPV) for isolated pulmonary stenosis in children less than a year of age were compared to a historical cohort of nineteen standard cases using fluoroscopy/angiography alone, which demonstrated equivalent procedural outcomes and safety, while achieving a median reduction in radiation (total dose area product) and contrast load of 80% and 84%, respectively. Our early experience demonstrates that EG-PBPV in neonates and infants has results equivalent to standard valvuloplasty but with less radiation and contrast.

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.

Balloon valvuloplasty of valvular pulmonary stenosis in a neonatal foal.

In a 1-day old filly with a loud heart murmur, transthoracic echocardiography revealed right ventricular hypertrophy associated with severe pulmonary valvular stenosis and a transvalvular pressure gradient (between right ventricle and pulmonary artery) of 125 mmHg. Computed tomographic angiography confirmed the finding, with no evidence of other relevant concurrent abnormalities. Balloon valvuloplasty was performed using a single balloon technique. The foal recovered well from anaesthesia. Following the procedure, the right ventricle-pulmonary artery transvalvular gradient decreased to 38 mmHg. At follow up examinations after 1 month, 1 year and 2 years, the filly showed normal exercise capacity and echocardiography confirmed the persistent substantial improvement in the transvalvular outflow gradient.

Immediate outcomes of low-pressure balloon valvuloplasty for severe pulmonary valve stenosis in 20 dogs: a retrospective, single-center case series.

INTRODUCTION: The primary objective of this study was to describe the immediate post-procedural outcomes in dogs with severe pulmonary stenosis that were treated with low-pressure balloon valvuloplasty (BV) at a single institution. ANIMALS, MATERIALS AND METHODS: Retrospective case series; medical records of dogs that underwent BV performed with a balloon dilation catheter >20 mm in diameter and a burst pressure of less than 4 atm (atm) were retrospectively reviewed. Twenty animals were identified fitting the criteria. Pre-procedural and post-procedural echocardiograms and peri-procedural angiograms were reviewed. Procedural success was defined as greater than 50% reduction in echocardiographically derived transpulmonary systolic pressure gradient (TPPG) or post-procedural TPPG of less than 50 mmHg. RESULTS: The median percent reduction from initial TPPG was 53% (range = 15-90%). Sixty percent of the dogs met the pre-specified criteria for a successful outcome. Post-procedural TPPG was not different based on valve types A or B (p=0.67), presence or absence of additional supravalvular (p=0.23) or subvalvular (p=0.83) obstructive components. DISCUSSION: The proportion of dogs that reach the successful outcome were not different based on valve type A or B. No relationship was noted between immediate outcomes and bodyweight or pulmonary annulus diameter. CONCLUSION: Dogs with severe pulmonic stenosis that underwent low-pressure BV had good immediate outcomes with no difference in outcome based on valve morphology. Further randomized controlled studies are needed to compare the outcomes of different strategies for BV in dogs with large-diameter pulmonary annulus.

Balloon valvuloplasty in 2 juvenile alpacas with severe valvular pulmonic stenosis.

Two juvenile alpacas, 1 male and 1 female, were presented for evaluation of grade V/VI bilateral basilar systolic heart murmurs. Both animals were ultimately diagnosed with severe valvular pulmonic stenosis and a small ventricular septal defect. Transvenous balloon valvuloplasty was performed in each animal using methods described in the dog. A double balloon technique was employed in the first case, with a balloon-annulus ratio of ~1.55. For the second case, a high-pressure dilatation balloon catheter with a balloon-annulus ratio of ~1.33 was selected. Experience with both procedures indicates that balloon pulmonary valvuloplasty is technically feasible in alpacas using techniques extrapolated from those used in dogs. Furthermore, accepted criteria for procedural success were fulfilled for both alpacas, with more than a 50% reduction in the echocardiographically derived transpulmonic pressure gradient after intervention.

The use of dexmedetomidine during pulmonic balloon valvuloplasty in dogs.

BACKGROUND: Information regarding the anaesthetic management for pulmonic balloon valvuloplasty (PBV) in dogs is scarce. We present data from dogs receiving dexmedetomidine combined with inhalational anaesthesia during PBV. METHODS: Anaesthetic records from dogs receiving dexmedetomidine (n = 11) and a control group (n = 29) anaesthetised for PBV between 2012 and 2020 were analysed. Intraoperative variables potentially affected by dexmedetomidine administration were compared between groups. RESULTS: Demographic characteristic and anaesthetic agents administered were similar between groups. The incidence of hypotension (mean arterial pressure (MAP) < 60 mm Hg) was 25% for dexmedetomidine and 29% for control (p = 0.8); however, dexmedetomidine group received vasopressors for a shorter time (p = 0.02). The incidence of bradycardia was 100% and 96% for dexmedetomidine and control (p = 0.5), but antimuscarinic agents were administered more frequently to the latter (p = 0.014). CONCLUSION: Dexmedetomidine may be a useful adjuvant to general anaesthesia during PBV in dogs and reduced the use of vasopressors and antimuscarinics.

Repeat balloon valvuloplasty for dogs with recurrent or persistent pulmonary stenosis.

INTRODUCTION/OBJECTIVES: Pulmonary stenosis (PS) is a common congenital defect in the dog. Severe valvar PS can be treated with balloon valvuloplasty (BV) to reduce obstruction severity and improve clinical signs. Repeat BV is often unnecessary, as restenosis is uncommon. Repeated pulmonary BV in people is generally successful and safe, but outcomes in dogs with recurrent or persistent stenosis have not been reported. The objectives of this study were to retrospectively evaluate outcomes of repeat BV in dogs. ANIMALS, MATERIALS, AND METHODS: Medical records and stored echocardiographic images were reviewed from dogs that received repeat BV for pulmonary valvar restenosis or persistent stenosis. Echocardiographic variables included maximum systolic ejection velocity (PVmax), velocity-derived maximal pressure gradient (PGmax) and velocity time integral (VTI) across the pulmonary valve, and ratios of pulmonic to aortic maximum velocity (PVmax/AVmax) and VTI (VTIPV/VTIAV). RESULTS: Twenty-three dogs were included; one underwent three BV procedures. The median time between BV procedures was 18.3 months (interquartile range, 6.3-43.6). One dog died during repeat BV, but no others experienced adverse effects. Reductions in PVmax, PGmax, and VTIPV after initial and repeat BV were 1.85 m/s, 76.2 mmHg, and 44.7 cm and 1.33 m/s, 55.6 mmHg, and 30.2 cm, respectively (all p < 0.01). Differences between pre-BV and post-BV PVmax, PGmax, VTIPV, PVmax/AVmax, and VTIPV/VTIAV were not different comparing initial to repeat BV (all p > 0.10). CONCLUSIONS: Repeat BV for recurrent or persistent PS is well tolerated and effective in a majority of dogs.

Semilunar Valve Interventions for Congenital Heart Disease: JACC State-of-the-Art Review.

Transcatheter balloon valvuloplasty for the treatment of aortic and pulmonary valve stenosis was first described nearly 40 years ago. Since that time, the technique has been refined in an effort to optimize acute outcomes while reducing the long-term need for reintervention and valve replacement. Balloon pulmonary valvuloplasty is considered first-line therapy for pulmonary valve stenosis and generally results in successful relief of valvar obstruction. Larger balloon to annulus (BAR) diameter ratios can increase the risk for significant valvar regurgitation. However, the development of regurgitation resulting in right ventricular dilation and dysfunction necessitating pulmonary valve replacement is uncommon in long-term follow-up. Balloon aortic valvuloplasty has generally been the first-line therapy for aortic valve stenosis, although some contemporary studies have documented improved outcomes following surgical valvuloplasty in a subset of patients who achieve tri-leaflet valve morphology following surgical repair. Over time, progressive aortic regurgitation is common and frequently results in the need for aortic valve replacement. Neonates with critical aortic valve stenosis remain a particularly high-risk group. More contemporary data suggest that acutely achieving an aortic valve gradient <35 mm Hg with mild aortic regurgitation may improve long-term valve performance and reduce the need for valve replacement. Continued study will help to further improve outcomes and reduce the need for future reinterventions.

Low prenatal detection rate of valvar pulmonary stenosis: What are we missing?

OBJECTIVES: Critical pulmonary stenosis (PS) and pulmonary atresia with intact ventricular septum (PAIVS) require urgent neonatal intervention. Since PS may be more insidious than PAIVS during gestation, we hypothesized that neonates with PS would have lower rates of prenatal detection than PAIVS. METHODS: We performed a retrospective chart review of all neonates who underwent diagnostic or interventional cardiac catheterization between 2000 and 2014 for critical PS or PAIVS. The rates of prenatal diagnosis were calculated for PS and PAIVS. Prenatal and postnatal echocardiographic data were reviewed. RESULTS: 178 patients met inclusion criteria: 91 with critical PS and 87 with PAIVS. The prenatal diagnosis rate for critical PS was lower than for PAIVS at 37% (34/91) vs 60% (52/87) (P = .003). At the time of diagnosis at a median gestational age of 25 weeks, the median TV z-score for patients with critical PS was larger than in PAIVS (-0.15 vs -3.0 P = .004). CONCLUSION: Critical PS had a lower prenatal detection rate than PAIVS, likely due to a relatively normal 4-chamber view at the time of routine second trimester screening in patients with PS. Color flow Doppler of the outflow tracts may improve detection, since outflow tracts may appear normal by 2D imaging.

Evaluation of the NuCLEUS-X™ balloon valvuloplasty catheter for severe pulmonic stenosis in dogs.

INTRODUCTION/OBJECTIVES: Balloon instability is commonly encountered during balloon pulmonary valvuloplasty (BPV) and may result in an unsuccessful procedure. The NuCLEUS-X™ catheter is a recently developed BPV catheter with a unique barbell shape and an ordered pattern of inflation that stabilizes the balloon to span the valve annulus before expansion of the balloon center. ANIMALS: Ten client-owned dogs with severe valvular pulmonic stenosis (PS). MATERIALS AND METHODS: Prospective observational study. The BPV procedure was performed by standard technique with use of NuCLEUS-X™ catheters targeting a balloon-to-annulus ratio between 1.2 and 1.5. Balloon stability, safety, and procedural success were assessed. Procedural success was defined as either a reduction in the Doppler transpulmonic PG by at least 50% of the pre-procedural PG or <80 mmHg one month post procedure. RESULTS: Balloon stability centered at the pulmonic valve on the first inflation was achieved in 10/10 cases. The mean PG before BPV was 141 mmHg ±41 mmHg, and the PG after BPV at one month was 83 mmHg ±41 mmHg. Procedural success was achieved in 56% of patients. All dogs survived the BPV, and no major procedural complications were encountered using the NuCLEUS-X™ catheter. CONCLUSIONS: The use of the NuCLEUS-X™ catheter is feasible for BPV in dogs with severe PS. The unique balloon shape provided catheter stability on the first inflation in all dogs, which may be beneficial when stabilization of a conventional BPV catheter cannot be achieved.