Plasma N-terminal pro-brain natriuretic peptide concentrations before and after pericardiocentesis in dogs with cardiac tamponade secondary to spontaneous pericardial effusion.

OBJECTIVE: To determine if concentrations of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) are increased in dogs with cardiac tamponade and if there is a significant increase in plasma NT-proBNP after pericardiocentesis. ANIMALS: Ten client-owned dogs with spontaneous cardiac tamponade. METHODS: Prospective clinical study. Cardiac tamponade was suspected from physical examination and confirmed with echocardiography. Blood was collected and plasma NT-proBNP concentrations were measured before and 30-60 min following pericardiocentesis and resolution of cardiac tamponade. Within-subject changes in plasma NT-proBNP were compared by the Wilcoxon signed-rank test. RESULTS: The plasma NT-proBNP concentrations measured within the reference interval in seven of 10 dogs before pericardiocentesis and in six of 10 dogs following pericardiocentesis. Following pericardiocentesis, there was a statistically significant increase in median NT-proBNP concentration (733 pmol/L, range 250-3,297) compared with the values measured before (643 pmol/L, range 250-3,210, P = 0.004). The NT-proBNP concentration increased in 90% of the dogs following pericardiocentesis. CONCLUSIONS: An upper reference limit of 900 pmol/L for plasma NT-proBNP is insensitive for the diagnosis of pericardial effusion and cardiac tamponade in dogs. Plasma NT-proBNP concentration commonly increases following pericardiocentesis, perhaps related to improved ventricular filling and stretch.

Single-dose pharmacokinetics and cardiovascular effects of oral pimobendan in healthy cats.

INTRODUCTION: To investigate the pharmacokinetics and pharmacodynamics of oral pimobendan in conscious, healthy cats. ANIMALS: Eight healthy adult cats. MATERIALS AND METHODS: A randomised, single-blinded, crossover design was used. Two oral doses of pimobendan (0.625-mg [LD], 1.25-mg [HD]) and a control substance (3-mL water) were administered to each cat. Blood collection, echocardiography, and oscillometric blood pressure measurements were performed repeatedly for 12 h following each dose. Plasma concentrations of pimobendan and the active metabolite, O-desmethylpimobendan (ODMP), were quantified using ultra-high-performance liquid chromatography tandem mass spectrometry. Cardiovascular parameters were evaluated for between- and within-treatment effects over time using linear mixed modelling. RESULTS: Pimobendan was rapidly absorbed and converted to ODMP with the pimobendan AUC0-∞ greater than ODMP AUC0-∞ (ODMP:pimobendan AUC0-∞ ratio 0.6 [LD] and 0.5 [HD]) despite a longer elimination half-life of ODMP (pimobendan t1/2 0.8 h vs. ODMP t1/2 1.6 h [LD]; pimobendan t1/2 0.7 h vs. ODMP t1/2 1.3 h [HD]). Averaged across all time points, pimobendan increased several measures of systolic function; however, its effect could not be further characterised. Although treatment was well-tolerated, two cats vomited following HD and another had a ventricular premature beat recorded following LD. CONCLUSIONS: The lower ODMP:pimobendan AUC0-∞ ratio compared to that observed previously in dogs suggests reduced metabolism in cats. Treatment effects were observed in measures of systolic function; however, the duration of action and differences in effects between the two pimobendan doses could not be characterised. Further studies are required to evaluate pimobendan in feline cardiovascular medicine.

Antigen Concentrations as an Indicator of Clinical Remission and Disease Relapse in Cats with Histoplasmosis.

BACKGROUND: Treatment monitoring is subjective and disease relapse is common in cats with histoplasmosis. The Histoplasma antigen enzyme immunoassay (EIA) is a noninvasive test used for determining disease remission and detecting disease relapse in humans with histoplasmosis. The utility of the antigen EIA for these purposes in cats remains unknown. HYPOTHESIS/OBJECTIVES: Those Histoplasma antigen concentrations in urine and serum would decline with antifungal treatment and that antigen elimination would be an indicator of clinical remission in cats with histoplasmosis treated with antifungal treatment. ANIMALS: Fifteen client-owned cats with histoplasmosis. METHODS: Masked observational study. Cats were monitored monthly during antifungal treatment. Time of clinical remission and serum and urine antigen elimination were determined for each cat. RESULTS: Twelve of 15 cats achieved clinical remission. At the time of diagnosis, antigen was detectable in urine in 14/15 (93%) cats and in serum in 11/15 (73%) cats. Both serum (P < .0005) and urine (P < .0001) antigen concentrations significantly decreased over time with effective treatment. Antigen elimination was sensitive [urine, 90.0% (95% CI 72.3-97.4%); serum, 90.4% (68.2-98.3%)] but less specific [urine, 64.6% (51.7-75.8%); serum, 52.1% (37.4-66.5%)] for disease remission. Urine antigen was positive in both cats and serum antigen was positive in 1 cat at the time of disease relapse. CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of Histoplasma antigen in urine and serum might be useful tests for determining disease remission and relapse in cats with histoplasmosis. Further research is needed to investigate the importance of low-level antigenemia and antigenuria.

Systolic arterial blood pressure estimated by mitral regurgitation velocity, high definition oscillometry, and Doppler ultrasonography in dogs with naturally occurring degenerative mitral valve disease.

INTRODUCTION: To determine if systolic blood pressure estimated by mitral regurgitation (MR) velocity can be used interchangeably with that estimated by high definition oscillometry (HDO) and Doppler ultrasonography (DU) in dogs with naturally occurring mitral valve disease (MVD). ANIMALS: Forty-nine client-owned dogs with naturally occurring MVD. MATERIALS AND METHODS: This is a retrospective study. Medical records were reviewed and dogs with MR caused by degenerative MVD were included if systolic blood pressure was estimated from MR velocity determined by continuous wave Doppler (CW), DU and HDO at the same visit. A Pearson product moment correlation coefficient was determined for each combination of measures and tested for significance with a paired t-test. Limits of agreement between 2 measures were determined by the 95% confidence interval of the average difference of the means and illustrated by Bland-Altman plots. RESULTS: Systolic pressure estimated from CW was significantly but only moderately correlated to DU (r = 0.42, p=0.0015) and HDO (r = 0.40, p=0.0021). Pressure estimated from DU was significantly but only moderately correlated to HDO (r = 0.57, p≤0.0001). Limits of agreement were wide for all measures including DU and CW (-61.9to 44.6 mmHg), HDO and CW (-65.2to 26.9 mmHg), and HDO and DU (-63.1 to 42.06 mmHg). DISCUSSION: Systolic blood pressure estimated by CW cannot be used interchangeably with HDO or DU in dogs with naturally occurring MVD.

The Effect of Chinese rhubarb, Rheum officinale, with and without benazepril on the progression of naturally occurring chronic kidney disease in cats.

BACKGROUND: Renal fibrosis is common in progressive kidney disease. Transforming growth factors ß (TGF-ß) are important mediators of all types of fibrosis, including renal fibrosis. Chinese rhubarb has been shown to have antifibrotic properties in part because of inhibition of TGF-ß and has slowed the progression of kidney disease in rodent models. HYPOTHESIS: That administration of a Chinese rhubarb supplement will slow the progression of chronic kidney disease (CKD) in cats and the concurrent administration of Chinese rhubarb and benazepril will be more effective than either alone. ANIMALS: Twenty-nine client-owned cats with naturally occurring IRIS Stage 2 or early Stage 3 CKD and without comorbidity such as cancer, urinary tract obstruction, urinary tract infection, poorly controlled hyperthyroidism, or systemic hypertension were enrolled in the study. METHODS: A randomized, positive-controlled, prospective study was performed. Cats received Chinese rhubarb, benazepril, or both in addition to standard treatment for CKD. Repeated measures ANOVA was used to assess changes in serum creatinine concentration, body weight, hematocrit, urine protein: urine creatinine ratio (UPC), and systemic arterial blood pressure over time between and within treatment groups over an average of 22 months. RESULTS: No significant differences were detected in serum creatinine concentration, body weight, hematocrit, UPC, and systemic arterial pressure over time between or within treatment groups. CONCLUSIONS AND CLINICAL IMPORTANCE: This study failed to detect a significant difference in the progression of CKD in cats treated with Chinese rhubarb, benazepril, or both. Further study in specific subsets of cats with CKD is warranted.