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.

Long-term Stability of a Compounded Suspension of Torsemide (5 mg/mL) for Oral Administration.

BACKGROUND: Torsemide use for congestive heart failure (CHF) has been reported, but prescription frequency is unknown. Commercially available tablet sizes in North America limit dosing precision, indicating a need to evaluate its strength and stability in suspension. OBJECTIVES: To determine the frequency of torsemide prescriptions and to determine a beyond use date (BUD) of a compounded suspension of torsemide for oral administration stored under 2 temperature conditions for 90 days. ANIMALS: No animals used. METHODS: Pharmacy records were retrospectively reviewed for torsemide and furosemide prescriptions from 2008 to 2015 at 2 veterinary referral centers. After preliminary strength testing, compounded torsemide suspension (5 mg/mL) for oral administration was prepared using torsemide tablets suspended in OraPlus:OraSweet 1:1, buffered to a pH of 8.3 and stored at refrigeration (2-8°C) and room temperature (20-25°C) in 2 oz amber plastic bottles. Samples were analyzed by reverse phase high-performance liquid chromatography (RP-HPLC) on days 0, 14, 30, 60, and 90. RESULTS: Prescriptions for torsemide increased from 2008 to 2015. Analysis of the torsemide 5 mg/mL suspension for oral administration at each time point met United States Pharmacopeia (USP) requirements for torsemide content of 90-110% of label claim. The average strength at 90 days decreased to 92 ± 3% at 2-8°C and 95 ± 2% at 20-25°C. Stability testing did not detect unknown impurities. CONCLUSIONS: Increasing torsemide use warrants availability of a validated and stable compounded formulation. Our results support the assignment of a 90-day BUD for torsemide 5 mg/mL suspension for oral administration compounded in OraPlus:Sweet 1:1 buffered to a pH of 8.3.

Relationship of plasma N-terminal pro-brain natriuretic peptide concentrations to heart failure classification and cause of respiratory distress in dogs using a 2nd generation ELISA assay.

BACKGROUND: Cardiac biomarkers provide objective data that augments clinical assessment of heart disease (HD). HYPOTHESIS/OBJECTIVES: Determine the utility of plasma N-terminal pro-brain natriuretic peptide concentration [NT-proBNP] measured by a 2nd generation canine ELISA assay to discriminate cardiac from noncardiac respiratory distress and evaluate HD severity. ANIMALS: Client-owned dogs (n = 291). METHODS: Multicenter, cross-sectional, prospective investigation. Medical history, physical examination, echocardiography, and thoracic radiography classified 113 asymptomatic dogs (group 1, n = 39 without HD; group 2, n = 74 with HD), and 178 with respiratory distress (group 3, n = 104 respiratory disease, either with or without concurrent HD; group 4, n = 74 with congestive heart failure [CHF]). HD severity was graded using International Small Animal Cardiac Health Council (ISACHC) and ACVIM Consensus (ACVIM-HD) schemes without knowledge of [NT-proBNP] results. Receiver-operating characteristic curve analysis assessed the capacity of [NT-proBNP] to discriminate between dogs with cardiac and noncardiac respiratory distress. Multivariate general linear models containing key clinical variables tested associations between [NT-proBNP] and HD severity. RESULTS: Plasma [NT-proBNP] (median; IQR) was higher in CHF dogs (5,110; 2,769-8,466 pmol/L) compared to those with noncardiac respiratory distress (1,287; 672-2,704 pmol/L; P < .0001). A cut-off >2,447 pmol/L discriminated CHF from noncardiac respiratory distress (81.1% sensitivity; 73.1% specificity; area under curve, 0.84). A multivariate model comprising left atrial to aortic ratio, heart rate, left ventricular diameter, end-systole, and ACVIM-HD scheme most accurately associated average plasma [NT-proBNP] with HD severity. CONCLUSIONS AND CLINICAL IMPORTANCE: Plasma [NT-proBNP] was useful for discriminating CHF from noncardiac respiratory distress. Average plasma [NT-BNP] increased significantly as a function of HD severity using the ACVIM-HD classification scheme.

Multicenter evaluation of plasma N-terminal probrain natriuretic peptide (NT-pro BNP) as a biochemical screening test for asymptomatic (occult) cardiomyopathy in cats.

BACKGROUND: B-type natriuretic peptide concentrations reliably distinguish between cardiac and respiratory causes of dyspnea, but its utility to detect asymptomatic cats with occult cardiomyopathy (OCM) is unresolved. HYPOTHESIS/OBJECTIVES: Determine whether plasma N terminal probrain natriuretic peptide (NT-proBNP) concentration can discriminate asymptomatic cats with OCM from normal cats, and whether NT-proBNP concentration correlates with clinical, biochemical, and echocardiographic parameters. ANIMALS: One hundred and fourteen normal, healthy cats; 113 OCM cats. METHODS: Prospective, multicenter, case-controlled study. NT-proBNP was prospectively measured and cardiac status was determined from history, physical examination, and M-mode/2D/Doppler echocardiography. Optimal cut-off values were derived using receiver operating characteristic (ROC) curve analysis. RESULTS: NT-proBNP was higher (median, interquartile range [25th and 75th percentiles]) in (1) OCM (186 pmol/L; 79, 478 pmol/L) versus normal (24 pmol/L; 24, 32 pmol/L) (P < .001); and (2) hypertrophic obstructive cardiomyopathy (396 pmol/L; 205, 685 pmol/L) versus hypertrophic cardiomyopathy (112 pmol/L; 48, 318 pmol/L) (P < .001). In OCM, NT-proBNP correlated (1) positively with LVPWd (ρ = 0.23; P = .01), LA/Ao ratio (ρ = 0.31; P < .001), LVs (ρ = 0.33; P < .001), and troponin-I (ρ = 0.64; P < .001), and (2) negatively with %FS (ρ = -0.27; P = .004). Area under ROC curve was 0.92; >46 pmol/L cut-off distinguished normal from OCM (91.2% specificity, 85.8% sensitivity); >99 pmol/L cut-off was 100% specific, 70.8% sensitive. CONCLUSIONS AND CLINICAL IMPORTANCE: Plasma NT-proBNP concentration reliably discriminated normal from OCM cats, and was associated with several echocardiographic markers of disease severity. Further studies are needed to assess test performance in unselected, general feline populations, and evaluate relationships between NT-proBNP concentrations and disease progression.

Minimally invasive per-catheter patent ductus arteriosus occlusion in dogs using a prototype duct occluder.

BACKGROUND: Per-catheter patent ductus arteriosus (PDA) occlusion in dogs with devices intended for humans is associated with technical difficulties, high rates of procedure abandonment, device migration, and residual ductal flow. HYPOTHESIS: Use of a custom-made canine duct occluder (Amplatz Canine Duct Occluder, ACDO) would be feasible in dogs of varying weights and somatotypes and effective in occluding a wide range of PDA shapes and sizes. ANIMALS: Eighteen client-owned dogs of various breeds with PDA. Weights ranged from 3.8 to 32.3 kg (median, 17.8 kg), and angiographic minimal ductal diameters ranged from 1.1 to 6.9 mm (median, 3.7 mm). Ductal morphologies included types IIA, IIB, and III. METHODS: Per-catheter PDA occlusion with the ACDO was performed in all dogs. Persistent or recurrent ductal flow was assessed at the end of the procedure by angiography and at 1 day, 3 months, and >or=12 months after the procedure by echocardiography. RESULTS: Successful ACDO placement was achieved in all 18 dogs. One dog required a 2nd procedure with a larger ACDO after the 1st device migrated to the pulmonary vasculature. Complete occlusion was confirmed in 17 of 18 dogs during the procedure, as well as at 1 day and 3 months after the procedure, and in 12 of 13 dogs evaluated at >or=12 months after the procedure. CONCLUSIONS AND CLINICAL IMPORTANCE: Per-catheter PDA occlusion in dogs with the ACDO is feasible and effective in dogs of a wide range of weights and somatotypes and with PDAs of varying shapes and sizes.