Congenital Pulmonic Stenosis a Retrospective study of 24 cases seen between 1990-1999

Evaluation of right ventricular diastolic function, systolic function, and circulating galectin-3 concentrations in dogs with pulmonary stenosis

BACKGROUND

Cardiovascular diseases with increased right ventricular (RV) afterload induce RV diastolic and systolic dysfunction, and myocardial fibrosis in humans. Studies in dogs with pulmonary stenosis (PS) evaluating RV diastolic function and markers of myocardial fibrosis are lacking.

HYPOTHESIS/OBJECTIVES

Dogs with PS have echocardiographic evidence of RV diastolic and systolic dysfunction and increased serum concentrations of galectin-3 (Gal-3), a surrogate biomarker for myocardial fibrosis.

ANIMALS

Forty client-owned dogs (10 controls, 30 with PS).

METHODS

Prospective study. All dogs had systemic blood pressure measurement, serum biochemical analysis, echocardiography, and measurement of serum Gal-3 concentration performed.

RESULTS

Variables of RV diastolic function were obtained in 39/40 dogs. Trans-tricuspid flow velocity in early diastole to trans-tricuspid flow velocity in late diastole ratios (RV E/A) were lower (P < .001) in dogs with PS (median, 0.94; range, 0.62-2.04) compared to controls (1.78; 1.17-2.35). Trans-tricuspid flow velocity in early diastole to tricuspid annular myocardial velocity in early diastole ratios (RV E/e') were higher (P < .001) in dogs with PS (11.55; 4.69-28) compared to control (6.21; 5.16-7.21). Variables of RV systolic function were lower in dogs with PS (P = <.001). Serum Gal-3 concentration was higher (P = .002) in dogs with PS (285.1 pg/mL; 94.71-406.97) compared to control dogs (162.83 pg/mL; 52.3-232.82).

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with PS have RV diastolic and systolic dysfunction, and increased Gal-3 concentrations. These findings suggest the presence of RV myocardial fibrosis in dogs with PS, which could impact clinical management.

Integrative echocardiographic assessment of post-operative obstruction severity and restenosis after balloon valvuloplasty in 81 dogs with pulmonary stenosis

INTRODUCTION/OBJECTIVES

Pulmonary stenosis (PS) is a congenital defect in the dog that is managed with balloon valvuloplasty (BV). Obstruction severity is routinely assessed using transthoracic echocardiography. The objectives of this study were to describe the short-term changes and long-term restenosis by retrospectively evaluating flow-dependent and flow-independent echocardiographic variables for dogs with PS after BV.

ANIMALS, MATERIALS, AND METHODS

Medical records and stored echocardiographic images were reviewed from dogs that received BV for PS. The following echocardiographic variables were measured or calculated: maximum systolic ejection velocity (Vmax_PV) and velocity-derived maximal pressure gradient (PV maxPG) across the pulmonary valve; ratio of aortic to pulmonary velocity time integral (VTI_AV/VTI_PV); ratio of aortic to pulmonary maximal velocity.

RESULTS

Eighty-one dogs with PS that had a BV were included. Each of these dogs had pulmonary obstruction severity assessed in at least three timepoints. Forty-nine dogs had at least one additional examination performed, the last of which occurred a median of 504 days after the BV. Echocardiographic variables at the first follow-up had increased by a clinically relevant quantity in 20-34% of the dogs when comparing to the immediate post-BV examination. The last follow-up examination identified valve restenosis in 18-38% of the dogs in this study. Valve type and pre-BV obstruction severity did not have a significant effect (P > 0.1).

CONCLUSIONS

For the assessment of BV efficacy, the immediate post-BV echocardiogram may not be as useful as the first follow-up examination several months later. Pulmonary restenosis after BV may be more prevalent than previously reported.

Age of puppies at referral to veterinary cardiology specialists for murmur investigation

Background

Cardiac auscultation is an important screening test at the first health examination of puppies because most clinically relevant congenital cardiac anomalies cause a loud murmur from birth. This retrospective study aimed to investigate the age at which dogs with suspected congenital cardiac anomalies were referred to a veterinary cardiology specialist for murmur investigation. A secondary aim was to establish the time interval between the visit to the cardiologist and the first available murmur documentation. The digital archive of a veterinary teaching hospital was searched for dogs with congenital cardiac anomalies and puppies with innocent murmurs during a 5-year period. Dogs had to be referred because of a murmur, and they had to undergo physical examination and echocardiography by a veterinary cardiology specialist. The health certificate section of the pet passport, and the medical records from the referring veterinarian, were reviewed to identify the date when the murmur was first documented.

Results

Of the 271 included dogs, 94% had a congenital cardiac anomaly and 6% had an innocent murmur. The dogs’ median age was 190 days when they were examined by the cardiologist. Only 10% of the dogs were referred by the breeder’s veterinarian, while 90% of the dogs were referred by the new owner’s veterinarian. The median age of the first available murmur documentation by a first opinion veterinary practitioner was 95 days.

Conclusions

Only 10% of the puppies in the present study were referred to a veterinary cardiology specialist for murmur investigation before they were sold to a new owner. Referral prior to re-homing would have been feasible if the murmur had been detected and documented by the breeder’s veterinarian, if referral was offered by the breeder’s veterinarian and the referral was accepted by the breeder.

Identification and Clinical Significance of Heart Murmurs in Puppies Involved in Puppy Trade

The detection of a congenital heart defect at purchase is an important step in early detection from a clinical and legal standpoint. Indeed, some cardiac abnormalities may be corrected with surgery, and very often, treatment needs to be performed early before congestive heart failure or irreversible heart damage can occur. From a legal viewpoint, if the defect is revealed in a newly purchased puppy, the buyer may be required to return it and receive compensation. Puppies affected with congenital heart defects are likely to die prematurely, causing emotional suffering to the owner. Furthermore, by considering breed predisposition, early recognition allows breeders to avoid breeding from particular dogs with genetic defects and prevent the continuation of genetic defects in breeding lines. Given gaps in the literature about the recognition of murmurs in the puppy trade, the present article describes how to identify a heart murmur in a puppy during a pre-purchase examination and its significance from a clinical and legal viewpoint. In the canine population, the prevalence of cardiac defects ranges between 0.13 and 1.6%. Pulmonic stenosis is the most common defect found in puppies, followed by patent ductus arteriosus, subaortic stenosis, and ventricular septal defect. On the basis of the above considerations, the veterinarian should recognize and identify the murmur following a protocol for routine examination of puppies involved in trade.

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.

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 (VTI_PV/VTI_AV).

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 VTI_PV 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, VTI_PV, PVmax/AVmax, and VTI_PV/VTI_AV 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.

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.

A pilot study evaluating cutting and high-pressure balloon valvuloplasty for dysplastic pulmonary valve stenosis in 7 dogs

INTRODUCTION

This case series describes early experience and technical aspects of cutting balloon dilation followed by high-pressure balloon pulmonary valvuloplasty in dogs with dysplastic pulmonary valve stenosis.

ANIMALS

Seven client-owned dogs were enrolled in this study.

METHODS

Dogs were prospectively enrolled based on echocardiographic diagnosis of severe pulmonary valve dysplasia, defined as marked valve thickening with variable degrees of annular hypoplasia or subvalvar fibrous obstruction and a peak echocardiography-derived transpulmonary pressure gradient higher than 100 mmHg. Preinterventional and postinterventional hemodynamic data and transthoracic pressure gradients were obtained for all dogs. Recheck echocardiography varied in timing by client convenience, with maximum follow-up 35 months after intervention.

RESULTS

No intraprocedural or periprocedural mortality was observed. The only major complication was partial avulsion of a cutting blade related to exceeding recommended burst pressure of the device, which was not associated with obvious clinical consequence. Invasive hemodynamic measurements demonstrated an average reduction of 46% in peak systolic right ventricular-to-pulmonary artery pressure gradient (range, 31-77%). The echocardiographic results 24 h after procedure demonstrated an average reduction in pressure gradient of 43% (range, 20-66%), with late follow-up demonstrating an average reduction of 35% (range, 10-57%) compared with preprocedural echocardiography.

CONCLUSIONS

This procedure is a feasible therapeutic transcatheter intervention for dogs with dysplastic pulmonary valves and appears safe in this small cohort. The ideal selection criteria and rate of restenosis for this procedure is under investigation, and long-term follow-up and a large, randomized, controlled study are necessary to demonstrate efficacy.

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.