Longitudinal Prevalence of Hypertension,Proteinuria, and Retinopathy in Dogs with Spontaneous Diabetes Mellitus

Background

The prevalence and progression of vascular complications of spontaneous diabetes mellitus (DM) in dogs have not been described.

Objectives

To investigate the effects of duration of disease, as estimated by time since DM diagnosis, and glycemic control on prevalence of systemic hypertension, proteinuria, and diabetic retinopathy in dogs with spontaneous DM.

Animals

Seventeen client‐owned dogs with spontaneous DM.

Methods

Prospective, longitudinal observational study. Dogs with DM of less than 1 year''s duration were recruited and evaluated once every 6 months for 24 months. Recorded measures included indirect BP, urine albumin, protein and creatinine concentrations, serial blood glucose and serum fructosamine concentrations, ophthalmic examination, and a standardized behavioral questionnaire.

Results

Eleven dogs completed the 2‐year follow‐up period, during which the highest recorded prevalence of systolic and diastolic hypertension was 55 and 64%, respectively. Prevalence of microalbuminuria and elevated urine protein:creatinine ratio (UPC) ranged up to 73 and 55%, respectively. Prevalence of retinopathy ranged up to 20%. No significant effect of time since DM diagnosis or glycemic control was detected for any of the measures examined. Additionally, no significant associations between BP, urine albumin concentration, UPC and retinopathy were detected.

Conclusions and Clinical Relevance

With the exception of proteinuria, which was substantial in some cases, clinically deleterious diabetic vascular complications were not identified in dogs in this study.     

Changes in Systolic Blood Pressure over Time in Healthy Cats and Cats with Chronic Kidney Disease

Background

Hypertension is a common problem in older cats, most often associated with chronic kidney disease (CKD). Cross‐sectional studies have suggested that blood pressure in cats increases with age.

Hypothesis/Objectives

To determine whether blood pressure in cats increases with age and whether this occurs independently of the presence of CKD. To investigate risk factors for developing hypertension.

Animals/Subjects

Two hundred and sixty‐five cats with CKD and 133 healthy cats ≥9 years were retrospectively identified.

Methods

Four groups were created according to status at initial evaluation (CKD or healthy) and blood pressure at the last included visit (normotensive [NT] or developed hypertension [DH]): Healthy‐NT, Healthy‐DH, CKD‐NT and CKD‐DH. Systolic blood pressure (SBP) over time slopes were compared with 0 and between groups. Risk factors for the development of hypertension were investigated, and associations of biochemical and clinical variables with SBP were examined.

Results

Cats that were hypertensive at CKD diagnosis (n = 105) were not included in further analyses. Twenty‐seven cats with CKD and 9 healthy cats developed hypertension ≥3 months after diagnosis of CKD or their first visit. Systolic blood pressure significantly increased with age in all cats (P < .001). Healthy cats were at less risk than cats with CKD to become hypertensive (hazard ratio 0.2, P < .001), with creatinine being an independent risk factor for the development of hypertension.

Conclusions and Clinical Importance

The high prevalence of hypertension in azotemic cats in this study shows the importance of monitoring of SBP in elderly cats, and in particular in cats with CKD.     

An Open‐label Phase 1 Dose‐escalation Clinical Trial of a Single Intravenous Administration of Gemcitabine in Dogs with Advanced Solid Tumors

Background

A broad range of gemcitabine dosages have been used in dogs.

Hypothesis/Objectives

To determine maximally tolerated dose (MTD), dose‐limiting toxicity (DLT), and preliminary antitumor activity of intravenous administration of gemcitabine in dogs with advanced solid tumors.

Animals

Twenty‐two client‐owned dogs.

Methods

Dogs with advanced cancer were prospectively enrolled in an open‐label Phase 1 study of gemcitabine. Gemcitabine was administered as a 30‐minute intravenous bolus starting at 800 mg/m², using escalation of 50 mg/m² increments with 3 dogs per dose level. MTD was established based on the number of dogs experiencing DLT assessed after 1 cycle. Treatment continued until disease progression or unacceptable toxicosis. Additional dogs were enrolled at MTD to better characterize tolerability, and to assess the extent and duration of gemcitabine excretion.

Results

Twenty‐two dogs were treated at 4 dose levels, ranging from 800 to 950 mg/m². Neutropenia was identified as DLT. MTD was 900 mg/m². DLT consisting of grade 4 febrile neutropenia was observed at 950 mg/m² in 2 dogs. There were no nonhematologic DLTs. Twenty dogs received multiple doses, and none had evidence of severe toxicosis from any of their subsequent treatments. At 900 mg/m², 2 complete and 5 partial responses were observed in dogs with measurable tumors. The amount of gemcitabine excreted in urine decreased over time, and was undetectable after the first 24 hours.

Conclusions and Clinical Importance

The recommended dose of gemcitabine for future Phase 2 studies is weekly 900 mg/m². In chemotherapy‐naïve dogs with advanced solid tumor this dose level merits further evaluation.     

Acute Phase Proteins in Racehorses with Inflammatory Airway Disease

Background

Systemic inflammation is observed in horses with heaves and could also be present in horses with a lesser degree of pulmonary inflammation.

Hypothesis/Objectives

It was hypothesized that racehorses with inflammatory airway disease (IAD) have increased concentration of circulating acute phase proteins. The objective of this study was to compare serum acute phase proteins of racehorses with and without lower airway inflammation.

Animals

Serum from 21 client‐owned Standardbred racehorses with exercise intolerance and lower airway inflammation and serum from 10 client‐owned Standardbred racehorses with exercise intolerance without lower airway inflammation.

Methods

In a case–control study, serum samples from previously characterized horses presented for exercise intolerance with or without lower airway inflammation based on bronchoalveolar lavage fluid cytology were analyzed for serum amyloid A protein (SAA), C‐reactive protein (CRP), and haptoglobin using commercial ELISAs.

Results

There was no significant differences between groups for SAA (non‐IAD versus IAD, median (range): 3.47 (0.06–34.94) versus 6.33 (0.06–80) μg/mL, P = .49), CRP (10.87 (2.05–29.03) versus 4.63 (0.02–31.81) μg/mL, P = .23) or haptoglobin (900.36 (607.99–2018.84) versus 749.54 (530.81–1076.95) μg/mL, P = .09).

Conclusions and Clinical Importance

In this population of poorly performing racehorses in training, serum SAA, CRP, and haptoglobin were not helpful in distinguishing between horses with IAD from horses with exercise intolerance from other causes.     

Medullary Position at the Craniocervical Junction in Mature Cavalier King Charles Spaniels: Relationship with Neurologic Signs and Syringomyelia

Background

Medullary elevation (ie, medullary kinking) at the craniocervical junction (CCJ) is reported in dogs with Chiari‐like malformations (CM), but its diagnostic criteria and clinical relevance are unclear.

Objective

To describe the position of the medulla at the CCJ in mature cavalier King Charles spaniels (CKCS), and evaluate its relationship with clinical status and the presence of syringomyelia.

Animals

Thirty‐six CKCS, 5–12 years of age, including 16 asymptomatic dogs.

Methods

Dogs were assigned a neurologic grade; magnetic resonance imaging (MRI) of the CCJ then was performed. The presence of a CM and syringomyelia was recorded and syringomyelia severity was quantified. Medullary position was quantified using the medullary kinking index, the elevation angle and obex position relative to the foramen magnum. The relationship between medullary position measures and presence and severity of neurologic signs and syringomyelia was investigated.

Results

Chiari‐like malformation was found in 33 dogs; 26 of them had syringomyelia. Mean medullary kinking index was 46.4% (SD, 10.3), elevation angle was 132° (SD, 12) and obex position was 3.5 mm (SD, 0.8). A higher medullary kinking index was associated with the presence of neurologic signs (P = .0368). Obex position was associated with the presence (P = .0018) and severity of syringomyelia (P = .0164).

Conclusions and clinical importance

There is a significant association between medullary elevation and clinical signs, whereas more caudal brainstem positions appear related to the presence of syringomyelia.     

Antimicrobial Susceptibilities of Aerobic Isolates from Respiratory Samples of Young New Zealand Horses

Background

Decreased efficacy of antimicrobials and increased prevalence of multidrug resistance (MDR) is of concern worldwide.

Objectives

To describe and analyze bacterial culture and antimicrobial susceptibilities from respiratory samples submitted from young horses (4 weeks to 3 years old).

Animals

Samples from 289 horses were submitted to a commercial laboratory.

Methods

A retrospective database search of submissions made to a New Zealand veterinary laboratory between April 2004 and July 2014. The results of in vitro susceptibility testing by Kirby‐Bauer disc diffusion were described and tabulated for the major bacterial species isolated. Multiple correspondence analysis (MCA) was used to describe the clustering of MDR isolates and selected demographic variables.

Results

Overall, 774 bacterial isolates were cultured from 237 horses, the majority of these isolates were gram‐positive (67.6%; 95% CI 64.3–70.9%). Streptococcus spp. were the most common genus of bacteria isolated and were 40.1% (95% CI 36.6–43.5%) of the isolates cultured. Susceptibility of Streptococcus spp. to penicillin, gentamicin, and ceftiofur was >85%. Overall, gram‐negative susceptibility to ceftiofur, tetracycline, and TMPS was <75%. MDR was defined as resistance to 3 or more antimicrobials, and was found in 39.2% of horses (93/237; 95% CI 33.0–45.5%).

Conclusions and clinical importance

Culture and susceptibility results have highlighted that MDR is an emerging problem for young horses in New Zealand (NZ), where a bacterial respiratory infection is suspected. This should be considered when prescribing antimicrobials, and emphasizes the need for submission of samples for culture and susceptibility.     

Comparison of Forelimb and Hindlimb Systolic Blood Pressures and Proteinuria in Healthy Shetland Sheepdogs

Background

The prevalence of systemic hypertension (SHT) in Shetland Sheepdogs has not been reported.

Hypothesis/Objectives

SHT is common in Shetland Sheepdogs and positively correlated with proteinuria. Measurements of forelimb and hindlimb systolic arterial pressure (SAP) are comparable.

Animals

Seventy‐two clinically healthy, client‐owned Shetland Sheepdogs.

Methods

Forelimb and hindlimb SAP were recorded by Doppler ultrasonography. Proteinuria was quantified by urine dipstick, microalbuminuria, and protein:creatinine ratio (UPC). The relationship of UPC, anxiety, age, weight, and heart rate with forelimb SAP was evaluated.

Results

The mean forelimb and hindlimb SAP were 132 ± 20 and 118 ± 20 mmHg, respectively. The SAP exceeded 160 mmHg in 9 dogs, suggesting 13% prevalence of SHT. Four dogs had a UPC above 0.5; 2 of these had forelimb SAP exceeding 160 mmHg. Correlation of forelimb and hindlimb SAP was poor (r ² = 0.09; P = .011). Bland–Altman plots revealed substantial bias (−14 mmHg) between limb measurements with clinically unacceptable 95% limits of agreement (−60 to 33 mmHg). There was no correlation between forelimb SAP and UPC (P = .06) or anxiety level (P = .49). Age (P < .0001) and heart rate (P = .038) were significant predictors of forelimb SAP; weight (P = .73) was not.

Conclusions

Prevalence of SHT was 13% and not correlated with proteinuria. Forelimb and hindlimb SAP were poorly correlated; therefore, trends in an individual animal should be monitored using the same measurement site. Additionally, values for Doppler SAP were determined in Shetland Sheepdogs.     

Comparison of Efficacy of Long‐term Oral Treatment with Telmisartan and Benazepril in Cats with Chronic Kidney Disease

Background

The efficacy and benefits of telmisartan in cats with chronic kidney disease (CKD) have not previously been reported.

Hypothesis

Long‐term treatment of cats with CKD using telmisartan decreases urine protein‐to‐creatinine ratio (UP/C) similar to benazepril.

Animals

Two‐hundred and twenty‐four client‐owned adult cats with CKD.

Methods

Prospective, multicenter, controlled, randomized, parallel group, blinded clinical trial with noninferiority design. Cats were allocated in a 1 : 1 ratio to either telmisartan (1 mg/kg; n = 112) or benazepril (0.5–1.0 mg/kg; n = 112) PO q24 h. The primary endpoint was prospectively defined as the change in proteinuria (benazepril:telmisartan) based on a log transformed weighted average of UP/C change from baseline (AUC 0→t/t) as a percentage compared using a confidence interval (CI) approach. Changes of UP/C from baseline were assessed on all study days and corrected for multiple comparisons.

Results

Telmisartan proved noninferior to benazepril in controlling proteinuria (CI, −0.035 to 0.268). At Day 180, UP/C compared to baseline in the telmisartan group was significantly lower (−0.05 ± 0.31; P = .016), whereas in the benazepril group the change (−0.02 ± 0.48) was not statistically significant (P = .136). Similar results were obtained at all assessment points with significant decrease in UP/C occurring with telmisartan but not benazepril.

Conclusion and Clinical Importance

Both telmisartan and benazepril were well tolerated and safe. Telmisartan proved to be noninferior to benazepril and significantly decreased proteinuria relative to baseline at all assessment points whereas benazepril did not.     

Voluntary Surveillance Program for Equine Influenza Virus in the United States from 2010 to 2013

Background

Recent surveillance studies for equine respiratory viruses have shown that equine influenza virus (EIV) continues to be a prevalent respiratory virus of equids throughout the United States and Europe.

Objectives

To gain a better understanding of the prevalence and epidemiology of EIV shed by horses, mules and donkeys in the United States from March 2010 to November 2013.

Animals

2,605 equids.

Methods

Nasal secretions from index cases with acute onset of respiratory disease were tested by qPCR for EIV. Multilevel logistic regression was used to model the association between EIV status and prevalence factors. Furthermore, observations from EIV‐positive study horses were compared to previous data from March 2008 to February 2010.

Results

A total of 230 (9.7%) index cases tested qPCR positive for EIV. A higher‐than‐expected proportion of EIV qPCR‐positive horses occurred in the 1–5, 6–10, and 11–15 age groups when compared to the <1 year of age group. Fever, nasal discharge and coughing were positively associated with EIV‐positive horses. EIV qPCR‐positive study cases were significantly older and more often vaccinated against EIV compared to EIV qPCR‐positive animals from the 2008‐2010 study period.

Conclusions and Clinical Importance

This study provides valuable and contemporary information on the frequency of EIV detected by qPCR in the United States. The results also underscore that older and previously vaccinated horses were susceptible to EIV.     

Sound Pressure Levels in 2 Veterinary Intensive Care Units

Background

Intensive care units (ICUs) in human hospitals are consistently noisy environments with sound levels sufficient to substantially decrease sleep quality. Sound levels in veterinary ICUs have not been studied previously, but environmental sound has been shown to alter activity in healthy dogs.

Hypothesis

Veterinary ICUs, like those in human medicine, will exceed international guidelines for hospital noise.

Animals

NA.

Methods

Prospective, observational study performed consecutively and simultaneously over 4 weeks in 2 veterinary ICUs. Conventional A‐weighted sound pressure levels (equivalent continuous level [a reflection of average sound], the sound level that is exceeded 90% of the recording period time [reflective of background noise], and maximum sound levels) were continuously recorded and the number of spikes in sound >80 dBA were manually counted.

Results

Noise levels were comparable to ICUs in human hospitals. The equivalent continuous sound level was higher in ICU1 than in ICU2 at every time point compared, with greatest differences observed on week day (ICU1, 60.1 ± 3.7 dBA; ICU2, 55.9 ± 2.5 dBA, P < .001) and weekend nights (ICU1, 59.9 ± 2.4 dBA; ICU2, 53.4 ± 1.7 dBA, P < .0001) reflecting a 50% difference in loudness. Similar patterns were observed for the maximum and background noise levels. The number of sound spikes was up to 4 times higher in ICU1 (162.3 ± 84.9 spikes) than in ICU2 (40.4 ± 12.2 spikes, P = .001).

Conclusions and Clinical Importance

These findings show that sound in veterinary ICUs is loud enough to potentially disrupt sleep in critically ill veterinary patients.     

Plasma C‐Reactive Protein and Haptoglobin Concentrations in Critically Ill Neonatal Foals

Background

Accurate diagnostic markers for sepsis in neonatal foals are needed. Plasma C‐reactive protein concentration (p[CRP]) and haptoglobin concentration (p[Hp]) are well‐established biomarkers of infection in humans, but studies are lacking in foals.

Hypotheses

p[CRP]) and p[Hp] are increased in septic foals compared to sick nonseptic and healthy control foals, and are predictive of survival.

Animals

Eighty critically ill foals (40 septic, 40 sick nonseptic) and 39 healthy control foals <1 week of age.

Methods

Multicenter, prospective observational clinical study. Venous blood was collected at admission from septic and sick nonseptic foals and from clinically healthy foals at 24 h of age. A diagnosis of sepsis was made based on positive blood culture or a sepsis score >11, and p[CRP] and p[Hp] were measured by using ELISA tests. Data were analyzed by using the Mann‐Whitney U‐test and forward stepwise multivariable linear regression. P < .05 was considered significant.

Results

Plasma [CRP] was positively associated with age, serum globulin, adrenomedullin, and bilirubin concentrations, aspartate aminotransferase activity, glutamyl‐transferase activity, band neutrophil count, and rectal temperature, and was increased in foals with toxic neutrophils, enterocolitis, colic, rib fractures and septic arthritis. Surprisingly, p[Hp] was lower in septic foals than in sick nonseptic foals. Neither p[CRP] or p[Hp] was predictive of survival in critically ill foals.

Conclusions and Clinical Importance

Plasma [CRP] increases with inflammation in neonatal foals but is not indicative of sepsis. Single time point, admission sampling of p[CRP] and p[Hp] do not appear to be useful biomarkers for sepsis in foals.     

Changes in Serum and Urine SAA Concentrations and Qualitative and Quantitative Proteinuria in Abyssinian Cats with Familial Amyloidosis: A Five‐year Longitudinal Study (2009–2014)

Background

Diagnosis of familial amyloidosis (FA) in Abyssinian cats usually is made on postmortem examination.

Hypothesis/Objectives

Sequential analysis of serum SAA (sSAA), urinary SAA (uSAA), urinary protein:creatinine (UPC) ratio, or sodium‐dodecylsulfate agarose gel electrophoresis (SDS‐AGE) may facilitate early identification of cats with FA.

Animals

Twenty‐three Abyssinian cats belonging to cattery A or B (low and high prevalence of FA, respectively).

Methods

Prospective longitudinal study using 109 blood and 100 urine samples collected over 4‐year period every 4 months, if possible, or more frequently in case of illness. Cats that died during study were necropsied. Health status of live cats was checked 5 years after enrollment. Serum amyloid A (sSAA) and urinary SAA (uSAA) were measured using ELISA kit. The UPC ratio and SDS‐AGE also was performed.

Results

Familial amyloidosis was not identified in cattery A, whereas 7/14 cats from cattery B had FA. Serum amyloid A concentrations were not significantly different between cats in catteries A and B or between cats with or without FA, despite frequent peaks in cats from cattery B. Conversely, uSAA was significantly higher in cattery B, especially in the terminal phases of FA. Proteinuria occasionally was found in cats from both catteries, especially in those with FA. Urine protein electrophoresis identified mixed proteinuria only in cats with FA.

Conclusions and Clinical Importance

Serum amyloid A and UPC ratio are not helpful for early identification of Abyssinian cats with FA. Conversely, increases in uSAA with or without mixed proteinuria may be found before onset of clinical signs in cats with FA.     

Estimating the Sensitivity and Specificity of Real‐Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals

Background

Real‐time, quantitative PCR (qPCR) methods for detecting Rhodococcus equi in feces have been developed as a noninvasive, rapid diagnostic test for R. equi pneumonia, but have not been evaluated in a large population of foals.

Objective

The objective of this study was to evaluate the clinical utility of fecal PCR as a diagnostic test for R. equi pneumonia in foals using receiver operating characteristic (ROC) methods.

Animals

186 foals born in 2011 at an R. equi‐endemic ranch in Texas.

Methods

Fecal samples were collected at the time of onset of clinical signs for pneumonic foals (n = 31). Foals with pneumonia were matched by age and birth date to healthy (n = 31) and subclinical (n = 124) control foals; fecal samples were collected from these controls. DNA was extracted from feces using commercial kits and concentration of virulent R. equi in feces was determined by qPCR.

Results

Concentration of R. equi in feces differed significantly (P < .05) among groups. The area under the ROC curve for fecal qPCR for diagnosis of R. equi pneumonia was 89% (95% CI, 83–99), with a sensitivity of 94% and specificity of 72%.

Conclusions and Clinical Importance

qPCR of feces can be useful as an alternative to tracheobronchial aspiration for the diagnosis of R. equi in foals with clinical signs of pneumonia. Caution should be used in extrapolating results of this study to other populations because fecal concentration of R. equi might vary by geographic location or management practices.     

Plasma Cardiac Troponin I Concentration and Cardiac Death in Cats with Hypertrophic Cardiomyopathy

Background

The use of cardiac biomarkers to assist in the diagnosis of occult and symptomatic hypertrophic cardiomyopathy (HCM) in cats has been established. There is limited data describing their prognostic utility in cats with HCM.

Hypothesis

Circulating concentrations of N‐terminal B‐type natriuretic peptide (NTproBNP) and cardiac troponin I (cTnI) predict cardiac death in cats with HCM.

Animals

Forty‐one cats diagnosed with HCM at a veterinary teaching hospital, between February 2010 and May 2011.

Methods

Prospective investigational study. Plasma samples were collected from cats diagnosed with HCM and concentrations of NTproBNP and cTnI were analyzed at a commercial laboratory. Echocardiographic measurements from the day of blood sampling were recorded. Long‐term outcome data were obtained. Associations with time to cardiac death were analyzed using Cox proportional hazards models.

Results

When controlling for the presence/absence of heart failure and echocardiographic measures of left atrial size and function, cTnI > 0.7 ng/mL was independently associated with time to cardiac death. In univariable analysis, NTproBNP > 250 pmol/L was associated with cardiac death (P = .023), but this did not remain significant (P = .951) when controlling for the effect of clinical signs or left atrial size/function.

Conclusions and Clinical Importance

Plasma concentration of cTnI (cutoff >0.7 ng/mL) is a predictor of cardiac death in cats with HCM that is independent of the presence of heart failure or left atrial dilatation.     

Urinary and Plasma Catecholamines and Metanephrines in Dogs with Pheochromocytoma,Hypercortisolism, Nonadrenal Disease and in Healthy Dogs

Background

Diagnosis of pheochromocytoma (PC) is based on a combination of clinical suspicion, finding an adrenal mass, increased plasma, and urine concentrations of catecholamine metabolites and is finally confirmed with histopathology. In human medicine, it is controversial whether biochemically testing plasma is superior to testing urine.

Objectives

To measure urinary and plasma catecholamines and metanephrines in healthy dogs, dogs with PC, hypercortisolism (HC), and nonadrenal diseases (NAD) and to determine the test with the best diagnostic performance for dogs with PC.

Animals

Seven PC dogs, 10 dogs with HC, 14 dogs with NAD, 10 healthy dogs.

Methods

Prospective diagnostic clinical study. Urine and heparin plasma samples were collected and stored at −80°C before analysis using high‐pressure liquid chromatography (HPLC) coupled to electrochemical detection or tandem mass spectrometry were performed. Urinary variables were expressed as ratios to urinary creatinine concentration.

Results

Dogs with PC had significantly higher urinary normetanephrine and metanephrine : creatinine ratios and significantly higher plasma‐total and free normetanephrine and plasma‐free metanephrine concentrations compared to the 3 other groups. There were no overlapping results of urinary normetanephrine concentrations between PC and all other groups, and only one PC dog with a plasma normetanephrine concentration in the range of the dogs with HC and NAD disease. Performances of total and free plasma variables were similar. Overlap of epinephrine and norepinephrine results between the groups was large with both urine and plasma.

Conclusion and clinical importance

Measurement of normetanephrine is the preferred biochemical test for PC and urine was superior to plasma.     

Clinical Severity Score System in Dogs with Degenerative Mitral Valve Disease

Background

Several risk factors already have been determined for dogs with degenerative mitral valve disease (DMVD). Risk factors often have been considered in isolation and have not always taken into account additional information provided by the history and physical examination (PE).

Hypothesis/Objectives

Data obtained from history and PE of dogs with DMVD provide prognostic information and can be used for risk stratification.

Animals

Client‐owned dogs (n = 244) with DMVD recruited from first opinion practice.

Methods

Prospective longitudinal follow‐up of dogs with DMVD. History and PE data were obtained at 6‐month intervals and analyzed with time‐dependent Cox models to derive relative risk of cardiac death. Independent hazard ratios were used to derive a clinical severity score (CSS), the prognostic value of which was evaluated by analyzing the median survival times for different risk groups and ROC analysis. Analysis of the progression of CSS over time also was undertaken.

Results

History of cough, exercise intolerance, decreased appetite, breathlessness (difficulty breathing) and syncope with PE findings of heart murmur intensity louder than III/VI and absence of respiratory sinus arrhythmia were independently associated with outcome and allowed development of the CSS. Clinical severity score distinguished groups of dogs with significantly different outcomes.

Conclusions and Clinical Importance

Routinely obtained clinical findings allow risk stratification of dogs with DMVD. Results of ancillary diagnostic tests may be complementary to history and PE findings and always should be interpreted in conjunction with these findings.     

Relationship between lean body mass and serum renal biomarkers in healthy dogs

Background

Symmetric dimethylarginine (SDMA) is an accurate and precise biomarker for estimating glomerular filtration rate (GFR) in humans and cats. Serum creatinine (sCr) also correlates with GFR, but has limitations as a biomarker of renal function because nonrenal factors can influence its concentration.

Hypothesis

Differences in lean body mass (LBM) influence sCr, but not serum SDMA concentrations.

Animals

Forty‐one healthy Beagles, mean age 9.9 years (range: 3.1–14.8 years), were studied over a 6 month period.

Methods

Serum biomarkers of renal function were measured prospectively at baseline, and 1, 3, and 6 months. SDMA concentrations were measured by liquid chromatography‐mass spectroscopy and sCr concentrations by enzymatic colorimetry. Body composition was determined by dual energy x‐ray absorptiometry.

Results

LBM (P < .001) and age (P = .006) were significant explanatory variables for sCr concentration (R ²  = 0.38), but not SDMA concentration. Time on food was the only significant explanatory variable for SDMA concentration (R ²  = 0.49). SDMA concentrations decreased across time (P < .001). LBM was affected by sex (males > females; P = .02). Mature adult dogs (<8 years) had greater LBM compared with geriatric dogs (≥8 years; P < .001).

Conclusion and Clinical Importance

sCr concentrations, but not SDMA concentrations, are influenced by LBM, which limits sCr utility as a biomarker for monitoring renal function in dogs with decreased LBM. Reductions in LBM can lower sCr concentration and overestimate GFR. SDMA concentrations, but not sCr concentrations were influenced by time on food. SDMA could have clinical advantages over sCr in monitoring response to nutritional interventions.     

Brainstem Auditory Evoked Responses in Foals: Reference Values,Effect of Age,Rate of Acoustic Stimulation,and Neurologic Deficits

Background

Age and rate of acoustic stimulation affect peak latencies in brainstem auditory evoked responses (BAER) in humans. Those effects are unknown in foals.

Hypothesis/Objectives

Our goals were to (1) establish reference values for BAER in foals by using 3 different stimulation protocols, (2) evaluate the effects of age and stimulation frequencies on BAER tracing in foals up to 6 months old, and (3) compare the data with BAER obtained from foals with central nervous system (CNS) disorders.

Animals

Thirty‐nine neurologically normal foals and 16 foals with neurologic diseases.

Methods

Prospective observational clinical study. BAER recorded by using 3 protocols of stimulation (11.33 repetitions per second [Hz]/70 decibel normal hearing level [dBNHL]; 11.33 Hz/90 dBNHL; 90 Hz/70 dBNHL).

Results

No effect of age was observed in normal foals (P > .005). No significant difference was observed for latencies and interpeak latencies (IPL) when comparing foals with neurologic diseases and normal foals (P > .05), but 78.6% of foals with neurologic diseases had an asymmetry in their tracing, reflecting a difference in conduction time between the left and right side of the brainstem. Increasing the stimulation rate did not improve detection of CNS disorders.

Conclusions and Clinical Importance

We propose BAER reference values for foals up to 6 months of age by using 3 protocols. Most foals with neurologic deficits had abnormal BAER tracing.     

Gallium Maltolate as an Alternative to Macrolides for Treatment of Presumed Rhodococcus equi Pneumonia in Foals

Background

Macrolide‐resistant isolates of Rhodococcus equi are emerging, prompting the search for clinically effective alternative antimicrobials.

Hypothesis

The proportion of foals with ultrasonographic evidence of pneumonia presumed to be caused by R. equi that had a successful outcome when administered gallium maltolate (GaM) PO would not be more than 10% inferior (ie, lower) than that of foals receiving standard treatment.

Animals

Fifty‐four foals with subclinical pulmonary abscesses among 509 foals at 6 breeding farms in Kentucky.

Methods

Controlled, randomized, prospective noninferiority study. Foals with ultrasonographic lesions >1 cm in diameter (n = 54) were randomly allocated to receive per os either clarithromycin combined with rifampin (CLR+R) or GaM, and followed up for 28 days by daily physical inspections and weekly (n = 1 farm) or biweekly (n = 4 farms) thoracic ultrasound examinations by individuals unaware of treatment‐group assignments. Treatment success was defined as resolution of ultrasonographically identified pulmonary abscesses within 28 days of initiating treatment. Noninferiority was defined as a 90% confidence interval for the observed difference in CLR+R minus GaM that was ≤10%.

Results

The proportion of GaM‐treated foals that resolved (70%; 14/20) was similar to that of foals treated with CLR+R (74%; 25/34), but we failed to demonstrate noninferiority for GaM relative to CLR+R; however, GaM was noninferior to CLR+R treatment when results from a noncompliant farm were excluded.

Conclusions and Clinical Importance

Gallium maltolate is not inferior to macrolides for treating foals with subclinical pneumonia. Use of GaM might reduce pressure for macrolide‐resistance in R. equi.     

Cardiac Troponin I as Compared to Troponin T for the Detection of Myocardial Damage in Horses

Background

Different cardiac troponin I (cTnI) assays give different results. Only 1 manufacturer has marketed troponin T (cTnT) assays. Therefore, cTnT often is preferred for detection of myocardial infarction in human patients. Studies of cTnT in horses are limited.

Objectives

To compare a cTnI and a high‐sensitive cTnT assay (hs‐cTnT) in horses.

Animals

Cardiac troponin I and cTnT were determined in 35 healthy horses (group 1), 23 horses suspected to have primary myocardial damage (group 2a), and 41 horses with secondary myocardial damage caused by structural heart disease (group 2b).

Methods

All cTnI samples were analyzed at laboratory A (limit of detection [LOD]: 0.03 ng/mL), whereas cTnT samples were analyzed at 2 laboratories with the same hs‐cTnT assay (laboratory B, LOD: 10.0 pg/mL; laboratory C, LOD: 4.0 pg/mL).

Results

The median cTnI concentration in group 2a (0.90 ng/mL; range, 0.03–58.27 ng/mL) was significantly higher (P < .001) than in group 1 (0.03 ng/mL; range, 0.03–0.09 ng/mL) or group 2b (0.05 ng/mL; range, 0.03–30.92 ng/mL), and the optimal cut‐off for detection of primary myocardial damage was 0.095 ng/mL (sensitivity: 90.5%, specificity: 100%). Using an LOD of 10.0 pg/mL for all cTnT samples, a cut‐off value of 10.5 pg/mL was found, but sensitivity was low (42.9%). When only samples analyzed at laboratory C (n = 58) were included, a cut‐off of 6.6 pg/mL was found (sensitivity: 81%, specificity: 100%).

Conclusions and Clinical Importance

Despite large quantitative differences, cTnI and cTnT are both useful for detection of myocardial damage in horses.