Advances in the Treatment of Pulmonary Valve Stenosis

Transfemoral vein approach for balloon pulmonary valvuloplasty in a 1.2- kg dog

A 10-month-old, 1.2- kg, unspayed female Maltese dog presented with the chief complaint of a heart murmur. Echocardiography revealed a transpulmonary velocity of 5.28 m/s (estimated pressure gradient: 112 mmHg) and severe pulmonary valve stenosis with an estimated pulmonary valve annulus diameter of 7.2 mm. Given the dog's small size, a balloon pulmonary valvuloplasty via the femoral vein was considered. The pulmonary valve annulus was dilated thrice using a 10-mm balloon (balloon-to-annulus ratio: 1.39). After the balloon pulmonary valvuloplasty, right ventricular systolic pressure decreased from 125 to 78 mmHg. The interventional procedure was completed without serious complications. As of postoperative day 149, the maximum transpulmonary velocity decreased to 2.43 m/s (estimated pressure gradient: 24 mmHg), recurrence of pulmonary valve stenosis was not observed, and the patient was doing well clinically. In conclusion, an approach performed via the femoral vein in this 1.2-kg dog resulted in a successful procedure without significant complications.

Comparative transcatheter intervention for pulmonary valve stenosis: multicenter collaborative study across pediatric and veterinary cardiology centers

INTRODUCTION/OBJECTIVES

Transcatheter therapeutics have revolutionized treatment of pulmonary valve stenosis (PS). Further understanding of PS intervention may help improve outcomes for different species. This study describes characteristics and immediate outcomes in children and dogs undergoing balloon pulmonary valvuloplasty (BPV) or transpulmonary stent implantation for congenital PS.

ANIMALS, MATERIALS, AND METHODS

This is a multicenter, retrospective review from two pediatric and three veterinary centers. Demographics, procedural characteristics, and outcomes were assessed. Successful intervention was defined as a 50% reduction in transvalvar pulmonary pressure gradient (PG) within 24 h or final invasive transpulmonary gradient <40 mmHg.

RESULTS

Data (78 children; 165 dogs) from July 2019 to June 2021 were included, with BPV performed in 77 children and 145 dogs and stent implantation in one child and 20 dogs. Stenosis was valvar in 64 children (82%) and 141 dogs (86%; P=0.50). Mean (SD) initial echocardiographic peak PG was higher in dogs [122 mmHg (39 mmHg) vs. 70 mmHg (22 mmHg)]. More dogs received beta-blockade at intervention (92% vs. 3%). Congestive heart failure was evident in 14% of dogs but no children. Pulmonary valve annulus diameter and balloon-to-annulus ratio were smaller in children [8.7 mm (3.4 mm); 1.19 (0.3 mm)] vs. dogs [12.6 mm (4.2 mm); 1.28 (0.24 mm)]. Successful transcatheter intervention was achieved in 84% of dogs and 96% of children (P=0.008).

CONCLUSIONS

Valvar PS occurs in both children and dogs, although lesions might not be completely comparable. Preprocedural PG is higher, and beta-blockers are more commonly prescribed in dogs. Successful transpulmonary intervention can be achieved in most pediatric and canine patients.

Agreement of echocardiographic and catheterization-based methods of transpulmonary pressure gradient measurement in dogs

INTRODUCTION/OBJECTIVES

Doppler echocardiographic estimation of transpulmonary pressure gradient (PG) is widely used to determine severity of pulmonary valve stenosis and indication for transcatheter intervention. The objective of this study was to describe agreement between Doppler echocardiographic methods of transpulmonary PG estimation and direct peak-to-peak pressure gradient at catheterization (PGcath) in dogs. We hypothesized that with reference to PGcath, mean echocardiographic PG (PGecho-mean) would have less bias than peak modal instantaneous echocardiographic PG (PGecho-peak).

ANIMALS

Client-owned dogs with congenital pulmonary valve stenosis that underwent balloon pulmonary valvuloplasty at one of two veterinary teaching hospitals between June 2012 and May 2022 were included in this study.

MATERIALS AND METHODS

Cases that underwent transthoracic echocardiography and subsequent balloon pulmonary valvuloplasty separated by 30 or fewer days were retrospectively identified. For each echocardiogram, average PGecho-mean (mmHg) and average PGecho-peak (mmHg) were calculated from stored spectral Doppler recordings. Peak right ventricular-to-peak pulmonary artery PG data (mmHg) were obtained from catheterization reports. Bland-Altman analysis was used to assess agreement between echocardiographic and catheterization data.

RESULTS

Data from 209 dogs (n = 215 instances) were evaluated. Proportional bias, greater at higher gradients, was observed for PGecho-mean versus PGcath (P<0.001). A constant bias of -38.12 mmHg was observed for PGecho-peak versus PGcath (P=0.62). Bias for both echocardiographic variables had wide limits of agreement that increased with PG.

CONCLUSIONS

Mean Doppler echocardiographic systolic transpulmonary pressure gradient and PGecho-peak underestimated and overestimated PGcath, respectively, preventing their interchangeability with PGcath.

Self-Reported Management of Incidentally Detected Heart Murmurs in Puppies: A Survey among Veterinarians

BACKGROUND

Heart murmurs in puppies can be innocent or pathologic; the latter is almost always related to a congenital heart disease. Differentiating between these murmurs can be challenging for practicing veterinarians, but this differentiation is essential to ensure the best prognosis for puppies having a congenital heart disease. Our study aimed to reveal how veterinarians manage puppies with a heart murmur.

METHODS

A web-based questionnaire was sent to Dutch and Belgian veterinary practices.

RESULTS

Data from 452 respondents were analyzed. Though 88% of the respondents find detecting a heart murmur easy, only 9% find differentiating innocent murmurs from pathologic murmurs in puppies easy. Of the respondents, only 80% recommend immediate additional examination when detecting a loud heart murmur during the first veterinary health check at 6 weeks of age. Most of the respondents are aware that normal growth and the absence of clinical signs do not exclude severe congenital heart disease. Of the respondents, 31% were uncertain whether early surgical intervention could lead to improved outcomes.

CONCLUSIONS

Veterinarians are aware of the importance of echocardiography for puppies with a loud heart murmur, and recognize their limitations when differentiating an innocent from a pathological heart murmur in a puppy.

First reported long-term two- and three-dimensional echocardiographic follow-up with histopathological analysis of a transcatheter pulmonary valve implantation in a pet dog

Transcatheter pulmonary valve implantation (TPVI) is indicated for use in the management of failing pulmonary valves in humans. We report here the long-term follow-up of the first documented transcatheter pulmonary valve implanted in a client-owned dog. A one-year-old Beagle dog with severe congenital type A valvular pulmonic stenosis first underwent percutaneous balloon pulmonary valvuloplasty, leading two years later to severe pulmonary regurgitation. A TPVI using a Melody™ bioprosthetic valve was then successfully performed, with normalization of the right heart cavities. Repeated two- and three-dimensional transthoracic echocardiographic examinations combined with Doppler modes confirmed the appropriate position and function of the valve for four years. Mitral myxomatous valvular degeneration led to refractory left-sided congestive heart failure, and the dog was humanely euthanized. After postmortem examination, X-ray imaging and histopathological evaluation of the stent and the valve were performed. Ex-vivo imaging of the implanted valve using a Faxitron® Path radiography system and microscopic evaluation of the implanted stent and bioprosthetic leaflets did not show any relevant leaflet or stent alterations. This case provides a proof of concept in interventional veterinary cardiology, showing that TPVI can be performed in dogs with subsequent long-term maintaining normal pulmonary valve function.