Distribution of angiostrongylosis in Cornwall

One hundred and ninety-seven faecal samples were examined for Angiostrongylus vasorum larvae, from dogs throughout Cornwall, which were presented with one or more clinical signs consistent with infection, were known to eat slugs or snails or were related to an infected dog. Twenty samples (10-1 per cent) contained nematode larvae, of these A vasorum larvae were identified in eight (4-1 per cent) and larvae of Filaroides species in eight (4-1 per cent). Seven of the eight dogs positive for A vasorum were found to have been infected within an area six miles in diameter incorporating Redruth. Statistical analysis suggested that this aggregation of cases was unlikely to be a random event (P < 0–01). No correlation between published data on the distribution of the intermediate host, slugs and snails and the cases of A vasorum infection reported in this paper could be found. It is concluded that A vasorum infection is enzootic within a small area around Redruth in the mid-west of Cornwall.     

Hypovolaemic shock after anthelmintic treatment of canine angio-strongylosis

Canine angiostrongylosis was diagnosed in a whippet with typical signs of respiratory and circulatory distress. Subclinical Angiostrongylus vasorum infections were also demonstrated in two other whippets belonging to the same owner. All three dogs were given standard anthelmintic levamisole treatment combined with corticosteroids. Two days after initiation of treatment, one of the subclinically infected dogs developed severe hypovolaemic shock that required intravenous fluid therapy and corticosteriods to save its life. The shock is believed to have been caused by an anaphylactic reaction triggered by the rapid release of a large amount of worm antigen in the blood due to the rapid death of adult worms by levamisole. Thus, dog owners should be instructed to monitor dogs undergoing levamisole treatment against A vasorum. Alternatives to levamisole treatment of canine angiostrongylosis should be considered.     

Angiostrongylus vasorum in the anterior chamber of a dog's eye

An unusual case of Angiostrongylus vasorum infestation occurred in a three-year-old female cavalier King Charles spaniel. The dog presented with signs consistent with right otitis interna, followed by the appearance of a free-swimming nematode in the anterior chamber of the right eye. The dog died of acute heart failure before surgical removal of the parasite was possible. Post mortem examination confirmed the presence of large numbers of worms in the pulmonary artery and right ventricle. These worms were identified histologically as A vasorum.     

Lungworm infections (Angiostrongylus vasorum, Crenosoma vulpis, Aelurostrongylus abstrusus) in dogs and cats in Germany and Denmark in 2003–2007

Faecal samples of 4151 dogs from Denmark, 958 dogs from Germany and 231 cats from Germany with clinical signs were examined for lungworm larvae using the Baermann funnel technique between 2003 and 2007. In total, 3.6% of Danish and German dogs shed lungworm larvae. In Denmark, patent infections of dogs with Angiostrongylus vasorum were more prevalent (2.2%) than those with Crenosoma vulpis (1.4%). In Denmark, the majority of A. vasorum- (98%) and C. vulpis-infected (80%) dogs originated from Northern Zealand. The frequency of A. vasorum and C. vulpis infections in Danish dogs obviously decreased from 2003 to 2006. In Germany, canine faecal samples were found more frequently positive for C. vulpis than for A. vasorum larvae (2.4% and 1.2%, respectively). Lungworm-infected dogs originated mainly from southern and western Germany. Larvae of Aelurostrongylus abstrusus were detected in 5.6% of cats from Germany. Overall, a distinct seasonal pattern in the detection of infected dogs was apparent for A. vasorum in Denmark and C. vulpis in Germany. The relatively high number of lungworm-infected dogs and cats indicate that these parasitic diseases should be considered in differential diagnosis of cases of treatment-resistant respiratory/cardiopulmonary distress.     

Transmembrane stent placement for cor triatriatum dexter in six dogs

ObjectivesReport the long-term outcomes following transmembrane stent placement as a therapy for Cor Triatriatum Dexter (CTD).Materials and methodsRetrospective case series including six dogs with CTD treated with transmembrane stent placement. Follow-up information was obtained including the persistence of presenting clinical signs, additional therapies required, and survival.ResultsThe median follow-up time was 24 months (range 15–76 months). Long-term outcome was deemed excellent in four dogs (67%), good/fair in one dog (17%), and poor in one dog (17%). Three dogs had persistence of clinical signs of variable severity. These three dogs were Labrador Retrievers or their crosses with varying degrees of tricuspid valve dysplasia (TVD), two of which also had a right to left shunting patent foramen ovale (PFO). One of these three dogs died 23 months post-stent placement during attempted open-heart repair of the TVD and PFO. Another is alive 15 months post-operatively stable on medical therapy for right-sided congestive heart failure secondary to TVD. The final dog demonstrated improved but persistent mild exercise intolerance up to 76 months post-operatively associated with mild TVD and a concurrent PFO.ConclusionsTransmembrane stent placement for CTD is a viable long-term treatment option with improvement or resolution of clinical signs. In the presence of concurrent congenital heart disease, specifically Labradors with TVD, additional therapies may be necessary with a corresponding impact on prognosis.     

Recruitment of arteriovenous pulmonary shunts may attenuate the development of pulmonary hypertension in dogs experimentally infected with Angiostrongylus vasorum

ObjectivesThe purposes of this study were to evaluate if (1) Angiostrongylus vasorum-infected dogs recruit pulmonary arteriovenous (AV) shunts attenuating the development of pulmonary hypertension (PH), detectable using saline contrast echocardiography, (2) anthelmintic therapy causes an acute increase in pulmonary arterial pressure (PAP), (3) Tissue Doppler Imaging (TDI) allows detection of mild changes in right ventricular function secondary to pulmonary (vascular) disease.Animals6 healthy Beagle dogs, each infected with 200 A. vasorum larvae.MethodsConventional, TDI and contrast echocardiography, invasive PAP measurements before (T0), 7–12 weeks post infection (wpi, T1), and 1–5 days post therapy (dpt, T2).ResultsAll dogs had patent infections 7–8 wpi and respiratory signs 6–9 wpi. PAP was mildly but significantly increased at T2. Saline contrast echo was positive in 3/6 dogs at T1 and 4/6 dogs at T2. Pulmonary transit time did not change. Of all numeric echocardiographic parameters, only a non-significant decrease in the E′ wave and inversion of E′/A′ ratio in 3 dogs at T2 could be observed. Two of these had mild PH and negative saline contrast echocardiography.ConclusionA. vasorum infection causes only a mild increase in PAP following inoculation and anthelmintic therapy. The absence of important PH may in part be explained by the recruitment of AV shunts in the presence of vascular obstructive disease. TDI echocardiographic parameters may be more sensitive to detect mild changes in RV function than conventional parameters.     

Pulmonary Artery Thrombosis in Experimental Angiostrongylus vasorum Infection Does Not Result in Pulmonary Hypertension and Echocardiographic Right Ventricular Changes

Background: Dogs experimentally inoculated with Angiostrongylus vasorum develop severe pulmonary parenchymal lesions and arterial thrombosis at the time of patency. Hypothesis: A. vasorum‐induced thrombosis results in arterial hypoxemia, pulmonary hypertension (PH), and altered cardiac morphology and function. Animals: Six healthy Beagles experimentally inoculated with A. vasorum. Methods: Thoracic radiographs and arterial blood gas analyses were performed 8 and 13 weeks postinoculation (wpi) and 9 weeks posttherapy (wpt). Echocardiography was done before and 2, 5, 8, 13 wpi and 9 wpt. Invasive pulmonary artery pressure (PAP) measurements were obtained 8 wpi. Two untreated dogs were necropsied 13 wpi and 4 treated dogs 9 wpt. Results: All dogs had patent infections at 7 wpi and clinical respiratory signs at 8 wpi. Moderate hypoxemia (median PaO₂ of 73 and 74 mmHg) present at 8 and 13 wpi had resolved by 9 wpt. Echocardiographically, no evidence of PH and no abnormalities in cardiac size and function were discernible at any time point. PAP invasively measured at 8 wpi was not different from that of control dogs. Severe radiographic pulmonary parenchymal and suspected thrombotic lesions at 13 wpi were corroborated by necropsy. Most histopathologic changes had resolved at 9 wpt, but focal inflammatory, thrombotic, and fibrotic changes still were present in all dogs. Conclusion: In experimentally infected Beagles, pulmonary and vascular changes induced by A. vasorum are reflected by marked radiographic changes and arterial hypoxemia. These did not result in PH and echocardiographic changes in cardiac size and function.     

Assessment of the combination of spinosad and milbemycin oxime in preventing the development of canine Angiostrongylus vasorum infections

Angiostrongylus vasorum is an increasingly reported parasite in Europe that develops in dogs after ingestion of infective third stage larvae (L3) that reside in gastropod molluscs which are needed to complete the parasite's life-cycle. Infection can produce a diversity of clinical signs, determined by involvement of the respiratory, neurological, and/or coagulation system, with a likely fatal outcome in the absence of treatment. Few drugs have been shown to reliably prevent infection, and data on treatment of infections is limited. A controlled, randomized, partially blinded laboratory study was therefore executed to evaluate the efficacy and safety of a combination tablet of spinosad/milbemycin oxime in dogs inoculated with approximately 250 A. vasorum L3. Sixteen healthy nematode free adult dogs were randomly allocated to two study groups of 8 dogs each. Thirty days post inoculation (dpi) all dogs in the fed state were treated: dogs in group B were treated with spinosad and milbemycin oxime at the dose rates of 45–60 mg/kg and 0.75–1.0 mg/kg bodyweight, respectively, approximately the lower half portion of the expected full unit dose range; dogs in group A were treated with placebo tablets. All dogs were euthanized and necropsied 56–58 dpi. The heart and lungs were examined to determine the presence of A. vasorum. All placebo group dogs were infected at necropsy with counts ranging from 22 to 98 adult worms and a geometric mean worm count of 55.2. In contrast, the geometric mean worm count in the spinosad/milbemycin oxime group was 0.7 with worm numbers ranging from 0 to 8. The results of this study demonstrate that a single treatment with the tablet combination of spinosad and milbemycin oxime administered 30 dpi provided 98.8% preventive efficacy against development of adult A. vasorum infections. Monthly treatments with spinosad and milbemycin oxime have the potential to prevent the establishment of infections with A. vasorum in dogs.     

First report of Angiostrongylus vasorum (French heartworm) in red foxes (Vulpes vulpes) on Prince Edward Island

Objective To identify first-stage nematode larvae (L1) recovered from a red fox scat sample and adult female worms recovered from 2 red fox lungs at necropsy, using published molecular methods to confirm a morphological diagnosis of Angiostrongylus vasorum (French heartworm).Animal Red fox (Vulpes vulpes).Procedure Nematode larvae recovered from a Baermann examination survey of wild canid scats (n = 101) conducted from January 2017 to August 2020, were identified by size and morphology and subjected to PCR and DNA sequencing of the small subunit (SSU) rRNA gene, the large subunit (LSU) rRNA gene, or the second internal transcribed spacer (ITS2). In addition, these techniques were applied to adult female worms recovered from the heart/lungs of 2 red foxes (obtained from PEI trappers and stored frozen at −20°C since December of 2018 and 2020).Results Size and morphology of L1 recovered by Baermann examination from a wild canid scat sample (presumed to be red fox) collected near Montague, PEI and adult female worms recovered at necropsy from 2 red fox carcasses were identified as A. vasorum. Molecular analysis confirmed the larvae and adult worms were A. vasorum.Conclusion These findings indicated that A. vasorum has become endemic in the red fox population on PEI.Clinical relevance Angiostrongylus vasorum infection is potentially fatal in dogs. Veterinarians and regional diagnostic laboratories in the Maritime provinces should consider the possibility of A. vasorum infection in dogs with clinical signs of cardiopulmonary and/or central nervous system disease or bleeding disorders.     

The Natural Clinical History of Canine Congenital Subaortic Stenosis

The demographics and natural clinical history of canine congenital subaortic stenosis (SAS) were evaluated by retrospective analysis of 195 confirmed cases (1967 to 1991), 96 of which were untreated and available for follow-up evaluation. Of these, 58 dogs had left ventricular outflow systolic pressure gradients available for assessment of severity. All 195 dogs were used for demographic analysis. Breeds found to be at increased relative risk included the Newfoundland (odds ratio, 88.1; P < .001), Rottweiler (odds ratio, 19.3; P < .001), Boxer (odds ratio, 8.6; P < .001), and Golden Retriever (odds ratio, 5.5; P < .001). Dogs with mild gradients (16 to 35 mm Hg) and those that developed infective endocarditis or left heart failure were diagnosed at older ages than those with moderate (36 to 80 mm Hg) and severe (>80 mm Hg) gradients. Of 96 untreated dogs, 32 (33.3%) had signs of illness varying from fatigue to syncope; 11 dogs (11.3%) developed infective endocarditis or left heart failure. Exercise intolerance or fatigue was reported in 22 dogs, syncope in 11 dogs, and respiratory signs (cough, dyspnea, tachypnea) in 9 dogs. In addition, 21 dogs (21.9%) died suddenly. Sudden death occurred mainly in the first 3 years of life, primarily but not exclusively, in dogs with severe obstructions (gradient, > 80 mm Hg; odds ratio, 16.0; P < .001). Infective endocarditis (6.3%) and left heart failure (7.3%) tended to occur later in life and in dogs with mild to moderate obstructions. Left heart failure was uncommon in the absence of additional congenital defects or infective endocarditis. Dogs with mild obstructions lived longer than other groups and tended to remain asymptomatic. The majority of dogs with severe obstructions died before 3 years of age and had a high prevalence (8 of 15) of sudden death. The prognosis for long-term survival in dogs with untreated mild or moderate SAS is favorable (median survival, 30.5 and 51.1 months, respectively), while the prognosis for dogs with severe SAS is very poor (median survival, 18.9 months).     

Concurrent medical conditions and long-term outcome in dogs with nontraumatic intracranial hemorrhage

Nontraumatic intracranial hemorrhage is bleeding originating from the brain or surrounding structures. It results from blood vessel rupture and may be primary or secondary in origin. The magnetic resonance imaging (MRI) characteristics of 75 dogs with nontraumatic intracranial hemorrhage were reviewed to determine signalment; intracranial compartment involved, size and number of lesions; type and prevalence of concurrent medical conditions; and long‐term outcome. Hemorrhagic lesions were intraparenchymal (n = 72), subdural (n = 2) or intraventricular (n = 1). Thirty‐three of 75 dogs had a concurrent medical condition. A concurrent condition was detected in 13 of 43 dogs with a single lesion ≥5 mm and included Angiostrongylus vasorum infection, intracranial lymphoma and meningioma. Of the 20 dogs with multiple lesions ≥5 mm, 7 had A. vasorum infection, 2 had hemangiosarcoma metastasis, 5 had suspected brain metastasis, and 1 was septicemic. Of the 12 dogs with multiple lesions, 2 had hyperadrenocorticism, 2 had chronic kidney disease, and 1 had hypothyroidism. Of these five dogs, all were hypertensive and four died within 12 months. No dog had a single lesion <5 mm. Long‐term outcome was favorable in 26 of 43 dogs with single lesions ≥5 mm, 6 of 20 dogs with multiple lesions ≥5 mm, and 8 of 12 dogs with multiple lesions <5 mm. A. vasorum infection was the most common concurrent condition in dogs with nontraumatic intracranial hemorrhage (16/75), with an excellent outcome in 14 of 16 dogs. Prognosis in nontraumatic intracranial hemorrhage is reported in terms of concurrent medical conditions and the number and size of lesions. © 2012 Crown copyright. This article was written by M. Lowrie, F. Llabrés‐Diaz and L. Garosi of Davies Veterinary Specialists and L. De Risio and R. Dennis of the Animal Health Trust. It is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland     

Cranial mediastinal carcinomas in nine dogs*

Nine dogs were diagnosed with cranial mediastinal carcinomas. Based on histological and immunohistochemical analysis, four dogs were diagnosed with ectopic follicular cell thyroid carcinomas, one dog with ectopic medullary cell thyroid carcinoma, two dogs with neuroendocrine carcinomas and two dogs with anaplastic carcinomas. Clinical signs and physical examination findings were associated with a space‐occupying mass, although one dog was diagnosed with functional hyperthyroidism. Surgical resection was attempted in eight dogs. The cranial mediastinal mass was invasive either into the heart or into the cranial vena cava in three dogs. Resection was complete in six dogs and unresectable in two dogs. All dogs survived surgery, but four dogs developed pulmonary thromboembolism and two dogs died of respiratory complications postoperatively. Adjunctive therapies included pre‐operative radiation therapy (n = 1) and postoperative chemotherapy (n = 3). Three dogs had metastasis at the time of diagnosis, but none developed metastasis following surgery. The overall median survival time was 243 days. Local invasion, pleural effusion and metastasis did not have a negative impact on survival time in this small case series.     

Clinical signs,diagnosis and treatment of three dogs with angiostrongylosis in Ireland

: Infection with Angiostrongylus vasorum was diagnosed at necropsy on a dog that died from acute pulmonary haemorrhage, and on recovery of L1 larvae by Baermann examination of faeces from two dogs, one of which had abdominal pain and retroperitoneal haemorrhage, while the other had right-sided heart failure due to cor pulmonale. The presenting signs included syncope (one dog), exercise intolerance (two dogs), cough (two dogs), abdominal pain (one dog) and depression (one dog). One-stage prothrombin time and activated partial thromboplastin time were prolonged in two dogs, buccal mucosal bleeding time was prolonged in one dog and globulin was elevated in all three dogs. Two dogs were treated with fenbendazole and recovered.     

Evaluation of topical nalbuphine or oral tramadol as analgesics for corneal pain in dogs: a pilot study

Objective To evaluate the effectiveness of topical nalbuphine or oral tramadol in the treatment of corneal pain in dogs. Animals studied Fourteen male Beagle dogs. Procedures Dogs were divided into three treatment groups and sedated with dexmedetomidine (5 μ/kg IV). A 4 mm corneal epithelial wound was created in the right eye (OD) of all dogs. Sedation was reversed with atipamazole IM. All dogs received pre/post ophthalmic examinations. Post operatively, Group NB (n = 5) received topical 1% preservative‐free nalbuphine OD q8 h and an oral placebo PO q8 h. Group TR (n = 5) received tramadol (4 mg/kg) PO q8 h and topical sterile saline OD q8 h. Group CNTRL (n = 4) received topical sterile saline OD q8 h and an oral placebo q8 h. All dogs received topical 0.3% gentamicin OD TID until healed. Dogs were pain scored using a pain scoring system modified from the University of Melbourne pain scale at 0, 1, 2, 4, and 6 h, then every 6 h by observers masked to treatment, until corneal wounds were healed. Treatment failure was recorded if cumulative pain scores were above a minimum threshold of acceptable pain and rescue analgesia of morphine (1.0 mg/kg IM) was administered subsequently. Result Four dogs in Group NB, one dog in Group TR, and two dogs in Group CNTRL required rescue analgesia. There was no significant difference in the incidence of treatment failure between groups (P = 0.184). Mean time to rescue was 9.16 h. All corneal wounds were healed by 84 h. Conclusions The results of this study suggest tramadol rather than nalbuphine should be further investigated for the treatment of corneal pain.     

Results of adrenalectomy in 36 dogs with hyperadrenocorticism caused by adrenocortical tumour

Summary

A total of 38 adrenocortical tumours were removed from 36 dogs with hyperadrenocorticism. The surgical approach was by way of a unilateral flank laparotomy (32 dogs; 14 left and 18 right), a bilateral flank laparotomy (3 dogs) or a midline celiotomy (1 dog).

Two dogs were euthanized during surgery because their tumours could not be resected. Eight dogs died from post‐operative complications. Pancreatic necrosis with peritonitis was the most common cause of death. Eight of the 26 dogs that survived had signs of recurrence of hyperadrenocorticism. Unsuppressible hyperadrenocorticism was found in four dogs; one dog had probably pre‐existent pituitary‐dependent hyperadrenocorticism, and adrenocortical function could not be re‐examined in the remaining three dogs.

Among the 37 tumours examined microscopically expansion of neoplastic tissue into blood vessels was found in 22 of them. Four adrenal glands with adrenocortical tumours also contained phaeochromocytomas. Necropsy was performed in eight dogs. Metastases were found in the lungs of two dogs and in the lungs and liver in one dog.

In combination with the data of previous reports, it is suggested that histological findings in surgery specimens are not good predictors for the clinical outcome.     

Clinical and laboratory observations in 91 dogs infected with Dirofilaria immitis in northern Greece

The medical records of 91 dogs with heartworm (Dirofilaria immitis) infection were reviewed, and diagnoses were established by using parasitological and immunological methods. Twenty-one animals were asymptomatic (stage I), 57 had mild to moderate clinical signs (stage II), and 13 had the severe form of the disease including right congestive heart failure and the caval syndrome (stage III). Thoracic radiography revealed right ventricular enlargement in 38 of the dogs, pulmonary vascular enlargement in 43, and parenchymal lesions in 27. Only the cardiac and vascular changes were correlated positively with the clinical stages. D. immitis microfilaraemia was detected in 75 of 85 dogs. Occult infection occurred only in eight stage II and two stage III dogs. Thirty-two of the dogs were treated with thiacetarsamide and 39 were treated with melarsomine, and no differences were found in terms of drug efficacy or complication rate; nine stage II dogs suffered pulmonary thromboembolism and one suffered acute liver disease and there were six fatalities. The 50 treated dogs in stages II and III which were followed up for six months all recovered completely. The performance of 38 of 61 working dogs was completely restored, and the performance of another four was partially restored.     

Evaluation of fungal flora in normal and diseased canine ears

This study was undertaken to characterize otic fungal flora encountered in normal dogs, atopic dogs with no clinical or cytological evidence of otitis and dogs with otitis externa. Forty‐two normal dogs, 23 atopic dogs and 32 dogs with otitis were included in the study. Samples for otic fungal culture and cytology were obtained from all animals, for a total of 194 ears. Sixty‐seven ear samples (34%) were culture positive for saprophytic fungal organisms, as follows: 43 (64%) Penicillium species, 13 (19%) Aspergillus species and the remaining 17% comprised of various other saprophytic fungal organisms. Cytological evidence of saprophytic fungal colonization or infection was not found in any animal. There was no relationship between positive saprophytic fungal culture and any study group. Thirty‐three ear samples (17%) were positive for Malassezia pachydermatis. Cytological findings of Malassezia were significantly associated with positive culture for Malassezia (P = 0.006 left ear; P = 0.019 right ear). Furthermore, increased numbers of Malassezia led to a higher chance of positive culture (P = 0.003 left ear; P = 0.008 right ear; McNemar’s test). Malassezia pachydermatis was more likely to be cultured from ears with increased cerumen. Ear type (erect or pendulous) was not significantly associated with positive culture for Malassezia or saprophytic fungal organisms. There was no relationship between positive Malassezia culture and any study group; however, Malassezia was more likely to be cultured from individual dogs in the atopic or otitis groups that also had other dermatological signs consistent with allergic dermatitis and/or pyoderma (P = 0.031 left ear; P = 0.005 right ear).     

Pharmacokinetics of acetaminophen after intravenous and oral administration in fasted and fed Labrador Retriever dogs

Acetaminophen (paracetamol) is used in dogs to manage fever and mild pain. The aim of this study was to assess the pharmacokinetics of acetaminophen in both fed and fasted Labrador Retrievers after a single intravenous and oral administration (20 mg/kg). Six healthy dogs underwent three treatments in a randomized block study (a, n = 2; b, n = 2; c, n = 2). In phase one, group a received acetaminophen intravenously, group b and c orally after being fasted and fed, respectively. In phase two and three, groups were swapped, and the experiment was repeated. At the end of the trial, each dog received the same treatment. Acetaminophen plasma concentrations were detected using a validated HPLC‐UV method. The pharmacokinetic analysis was performed using a noncompartmental model. Clearance, volume at steady state and half‐life of acetaminophen in Labrador Retrievers were 0.42 L/kg hr, 0.87 L/kg and 1.35 hr, respectively. No significant statistical differences were found between fasted and fed dogs regarding maximum plasma concentration, time at maximum concentration and bioavailability as measured by the AUC. Feeding does not significantly affect the acetaminophen oral pharmacokinetics.     

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.