Preliminary Investigation of Cardiovascular-Renal Disorders in Dogs with Chronic Mitral Valve Disease

Prognostic value of circulating cardiac and renal biomarkers in dogs with myxomatous mitral valve disease

Prognostic evaluation of canine myxomatous mitral valve disease (MMVD) using circulating biomarkers has been attempted, but comprehensive studies are still limited. The present study aimed to investigate the prognostic value of circulating cardiac and renal biomarkers and imaging data in 37 small-breed dogs with MMVD using retrospective data obtained from 2018 to 2022. The circulating cardiac biomarkers included N-terminal probrain natriuretic peptide (NT-proBNP), atrial natriuretic peptide (ANP), and troponin I. The renal biomarkers included blood urea nitrogen (BUN), creatinine, symmetric dimethylarginine, and cystatin C (Cys-C). The imaging data included vertebral heart score, vertebral left atrial size (VLAS), left-atrial-to-aortic ratio, and left ventricle internal diameter in diastole normalized to bodyweight (LVIDDN) from the medical records. The dogs were categorized into high and low groups based on the cutoff values obtained from the receiver-operating characteristic curves. Kaplan-Meier survival curves were generated, and 1-year MMVD-specific survival rates were compared using the restricted mean survival time (RMST) method. The dogs with high VLAS, LVIDDN, and NT-proBNP, ANP, troponin I, BUN, creatinine, or Cys-C levels had significantly shorter MMVD-specific survival times (p < 0.01). NT-proBNP had the largest RMST difference of 187.0 days (95 % confidence interval [CI]: 104.7-269.3 days), followed by Cys-C with 169.3 days (95 % CI: 98.2-240.5 days). Our study findings highlight the potential of NT-proBNP and Cys-C as key prognostic markers in dogs with MMVD. Incorporating the measurements of blood circulating biomarkers may enhance the accuracy of prognostic prediction in dogs with MMVD.

Relationship Between Red Blood Cell Indices and Myxomatous Mitral Valve Disease in Small-Breed Dogs: A Retrospective Study

BACKGROUND

Red blood cell (RBC) indices provide information on the size and haemoglobin content of erythrocytes. The RBC distribution width (RDW) is an index of size variability of the circulating RBC population. The correlation between various diseases and RDW in dogs has been demonstrated. Some studies have evaluated RDW in dogs with myxomatous mitral valve disease (MMVD), and conflicting results have been reported.

OBJECTIVES

We aimed to evaluate the association between RBC indices, complete blood cell counts (CBC), and serum biochemical and echocardiographic variables in small-breed dogs with MMVD.

METHODS

RBC indices, CBC, and serum biochemical and echocardiographic variables were retrospectively investigated in 102 client-owned dogs with MMVD at various disease stages.

RESULTS

RBC indices were not statistically significant among groups (control group, compensated group, decompensated group). RDW had a significant positive correlation with haematocrit (Hct) (correlation coefficient, 0.452) and a negative correlation with MCH (correlation coefficient, -0.498) and MCV (correlation coefficient, -0.357). The end-diastolic volume index, fractional shortening (%), and left atrial-anteroposterior diameter normalised for body weight were echocardiographic variables that affected MMVD severity.

CONCLUSIONS

We observed no correlation between RBC indices and MMVD. However, conflicting results have been reported in several other studies; thus, further studies should be considered.

Detection of early renal perfusion changes by contrast-enhanced ultrasonography in dogs with preclinical myxomatous mitral valve disease

Since the prognosis of myxomatous mitral valve disease (MMVD) varies, its characterization is clinically relevant, and renal impairment has been identified as one of its associated factors. Intrarenal Doppler ultrasonography (IRD), an intrarenal hemodynamic assessment method, is useful for predicting cardiac- and renal-related death but cannot detect early changes in dogs with preclinical MMVD. Contrast-enhanced ultrasonography (CEUS), another intrarenal hemodynamic assessment method, may identify earlier changes; however, renal perfusion evaluations using CEUS have not yet been performed on dogs with MMVD. We hypothesized that CEUS detects changes earlier than IRD in dogs with preclinical MMVD. This prospective, cross-sectional study examined renal perfusion in dogs without cardiac disease and preclinical MMVD dogs of different American College of Veterinary Internal Medicine stages using CEUS and compared it with IRD indices. Twenty-three dogs with MMVD (ten stage B1 and thirteen stage B2) and 12 control dogs without cardiac disease were included. The rise times of the renal cortex and medulla were measured from a time-intensity curve. The rise time of the cortex was longer in dogs with stage B2 MMVD than in control dogs, while that of the medulla was shortened in the right ventricular dysfunction group in stage B2. No changes were observed in IRD indices (the resistance index and venous impedance index). In conclusion, CEUS detected changes in renal perfusion in dogs with preclinical MMVD even when IRD indices remained unchanged, suggesting the utility of CEUS in evaluations of renal perfusion in MMVD dogs.

How accurate are NT-proBNP, ANP, and cTnI levels in diagnosing dogs with myxomatous mitral valve disease?

Background

Myxomatous mitral valve disease (MMVD) is prevalent in dogs. Specialized diagnostics (radiography and echocardiography) may be unavailable in some veterinary settings. Cardiac biomarkers offer potential alternatives.

Aim

This study evaluated the diagnostic value of N-terminal fragments of pro-brain natriuretic peptides (NT-proBNPs), atrial natriuretic peptides (ANPs), and cardiac troponin I (cTnI) levels in dogs with MMVD.

Methods

69 dogs with MMVD (asymptomatic and symptomatic) and 19 healthy controls were assessed. Biomarker levels were measured using commercial kit rapid tests.

Results

Our results showed that the median NT-proBNP level in the symptomatic group was higher than those in the asymptomatic (p < 0.001) and control (p < 0.001) groups. Moreover, the median NT-proBNP level in the asymptomatic group was higher than that in the control group (p < 0.001). The cTnI level in the control group was lower than those in the asymptomatic (p = 0.039) and symptomatic (p = 0.001) groups. No statistically significant difference in the cTnI level was noted between the asymptomatic and symptomatic groups. The best cutoff value of the NT-proBNP level to differentiate the normal controls from dogs with MMVD with or without congestive heart failure was > 505.65 pmol/l [sensitivity, 76.8%; specificity, 89.5%; and area under the curve (AUC), 0.862]. The suggested cutoff value of the NT-proBNP level to differentiate symptomatic MMVD from asymptomatic MMVD was >787.65 pmol/l (sensitivity, 78.38%; specificity, 72.55%; and AUC, 0.792).

Conclusion

NT-proBNP and cTnI may serve as point-of-care tests for dyspneic dogs, aiding MMVD assessment where specialized diagnostics are limited.

Association between echocardiographic indexes and urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL) in dogs with myxomatous mitral valve disease

Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of tubular damage, and its elevation has been described in human and canine cardiorenal syndrome. The aim was to evaluate the association between echocardiographic indexes and urine NGAL (uNGAL) and uNGAL normalized to urine creatinine (uNGALC) in dogs with MMVD. This is a multicentric prospective cross-sectional study. A total of 77 dogs with MMVD at different ACVIM stages were included. All dogs underwent echocardiography, serum chemistry, and urinalysis. Echocardiographic data analyzed were shortening fraction (SF), left ventricular diastolic (LVIDDn) and systolic (LVIDSn) diameters normalized for body weight, left atrium to aortic root ratio (LA/Ao), maximal (LAVMax) and minimal (LAVMin) left atrial volumes, LA stroke volume (LASV), early diastolic mitral peak velocity (EVmax), EVmax to tissue Doppler E' wave (E/E'), aortic (VTIAo) and mitralic (VTIMit) velocity time integrals and their ratio (VTIMit/VTIAo), and tricuspid regurgitation velocity (TRVmax). In the univariate analysis LASV, TRVmax, LAVMax, LVIDDn, and VTIMit/VTIAo were independent predictors of increased uNGAL and uNGALC; however, only LASV [(OR: 1.96, 95% CI: 1.16 to 3.31) P = 0.01 for NGAL, and (OR: 2.79, 95% CI: 1.50 to 5.17) P < 0.001 for NGALC] and TRVmax [(OR: 1.73, 95% CI: 1.20-2.51) P = 0.002 for NGAL, and (OR: 1.50, 95% CI: 10.07-2.10) P = 0.015 for NGALC] remained statistically significant in the multivariable analysis. Based on our results, LASV and TRVmax are associated with increased uNGAL and uNGALC. These parameters might detect dogs with MMVD at higher risk of developing kidney damage.

A Pilot Study of the Role of Selected Biomarkers of Kidney Injury in Dogs with Dilated Cardiomyopathy

Heart and kidney diseases are among the most frequent medical conditions diagnosed in small animals. Due to the functional interconnection between these organs, the concept of the cardio-renal axis has been developed. In this context, renal disease or dysfunction often occurs secondary to heart diseases, such as dilated cardiomyopathy (DCM). DCM is the most common cardiomyopathy and a leading cause of mortality in large-breed dogs. Traditional biomarkers like creatinine or symmetric dimethylarginine concentration are not always effective, especially in the early stages of the disease, underscoring the need for more sensitive markers of renal impairment during heart failure (HF). This study aimed to evaluate the efficacy of selected biomarkers as indicators for early kidney damage in dogs with stage B2 DCM. We measured serum concentrations of cystatin C, KIM-1 (kidney injury molecule-1), and NGAL (neutrophil gelatinase-associated lipocalin) and their ratios to creatinine, analyzing their diagnostic values. Cystatin C was quantified using a sandwich enzyme immunoassay, while KIM-1 and NGAL were measured with enzyme-linked immunosorbent assay kits designed for canine diagnostics. The concentrations were indexed against serum creatinine. The study included 26 dogs: 9 with HF and 17 healthy controls. The mean ± standard deviation for healthy dogs for cystatin C, cystatin C/creatinine ratio, KIM-1, KIM-1/creatinine ratio, NGAL, and NGAL/creatinine ratio were 0.24 ± 0.04, 0.26 ± 0.07, 0.61 ± 0.07, 0.67 ± 0.13, 2.76 ± 1.8, and 2.79 ± 1.81, respectively. For DCM dogs, these values were 0.27 ± 0.1, 0.32 ± 0.12, 0.61 ± 0.08, 0.69 ± 0.17, 6.46 ± 5.22 (p = 0.02), and 7.99 ± 6.53 (p = 0.04). This study's findings suggest that during the asymptomatic phase of DCM, only NGAL concentration and the NGAL/creatinine ratio may serve as diagnostic markers for early-stage kidney injury.

Evaluation of progression of chronic kidney disease in dogs with myxomatous mitral valve disease

Introduction

Cardiovascular and renal diseases are known to affect each other in the cardiovascular renal axis disorder (CvRD). Although CvRD, which includes myxomatous mitral valve disease (MMVD) and chronic kidney disease (CKD), has been described in dogs, there are only a few reports on the progression of CKD in accordance with the severity of MMVD. The aim of this study was to evaluate whether the presence of MMVD is associated with the rate of progression of CKD in dogs. The time from the initial diagnosis to the worsening of the International Renal Interest Society (IRIS) stage and the time for the occurrence of hyperphosphatemia and isosthenuria were evaluated.

Materials and methods

In this retrospective study, CKD progression was determined as an increase in the IRIS stage by at least one level and the development of hyperphosphatemia or isosthenuria. The CKD progression was compared in dogs with and without comorbid MMVD.

Results

Dogs with CKD were divided into two groups: dogs with and without MMVD (n = 63, concurrent group; n = 52, CKD group, respectively). The concurrent group was further divided into two subgroups based on the American College of Veterinary Internal Medicine guidelines (B1 group, n = 24; B2 group, n = 39). The time for progression of CKD from IRIS stage 1 to IRIS stage 2 was significantly shorter in the concurrent group than in the CKD group (log-rank test, p < 0.001). MMVD was associated with an increased risk of progression from stage 1 to stage 2 (hazard ratio, 6.442; 95% confidence interval (CI), 2.354 to 18.850; p < 0.001). The timing of the onset of hyperphosphatemia or isosthenuria in the concurrent group and the CKD group was not significantly different.

Conclusion

The results of this study suggest that MMVD could be a risk factor for the progression of CKD. Our findings may help predict the prognosis of dogs with both CKD and MMVD compared to CKD only.

Proteinuria and Electrophoretic Pattern in Dogs with Comorbidities Associated with Chronic Kidney Disease

In animals with chronic pathologies, the detection of proteinuria via the proteinuria: creatininuria ratio (UPC) and urinary protein electrophoresis allows for the early diagnosis of chronic kidney disease (CKD). The objective of this work was to identify and determine the magnitude of proteinuria and its electrophoretic pattern characterization in dogs with chronic diseases pathophysiologically related to proteinuria. With the studied patients, five groups were formed. The control group (CG) contained non-proteinuric cases. The cases with proteinuria were classified into four groups according to the concurrent disease: chronic inflammatory diseases (IG), neoplasms (NG), heart diseases (HG), and endocrine diseases (EG). For the statistical analysis, descriptive statistics and non-parametric tests were used. Data from 264 dogs were obtained; in the disease groups, proteinuria was observed in more than 30% as the only finding of kidney disease, evidencing a greater risk factor for proteinuria in the HG group (OR 4.047, CI 1.894-8.644, p < 0.0001). In the HG, NG, and EG groups, a higher frequency of glomerular pattern (GEP) related to glomerular hypertension was observed; in the IG, a higher frequency of mixed pattern (MEP) was observed. These findings are secondary to the hyperfiltration process that affects the glomerulus and the renal tubule.

Red Blood Cell Distribution Width as a Novel Parameter in Canine Disorders: Literature Review and Future Prospective

Red blood cell distribution width (RDW) is a quantitative laboratory parameter applied for the measurement of anisocytosis and is a reliable and inexpensive method for clinical classification of anemia. An increased RDW reflects a great heterogeneity in the size of red blood cells typical of regenerative and iron-deficiency anemia. In humans, numerous and recent studies have shown a relationship between increased RDW and the risk of morbidity and mortality in patients with various disorders. In particular, a strong association has been established between changes in RDW and the risk of adverse outcome in humans with diseases affecting different organs or systems. Following the human literature, some studies have recently been conducted trying to clarify the clinical role of RDW in various animal disorders, particularly in dogs. In this review, we summarize and critically evaluate the results of the studies based on the measurement of RDW in dogs. We also emphasize the need for further and more extensive studies on the use of this simple and inexpensive parameter in animals.

Evaluation of urinary neutrophil gelatinase-associated lipocalin to detect renal tubular damage in dogs with stable myxomatous mitral valve disease

BACKGROUND

Dogs with myxomatous mitral valve disease (MMVD) can experience progressive renal tubular damage and dysfunction. The prevalence of renal tubular damage is not known in dogs with stable MMVD.

OBJECTIVE

To evaluate renal tubular damage in dogs with stable MMVD by evaluation of urinary neutrophil gelatinase-associated lipocalin (NGAL).

ANIMALS

Ninety-eight MMVD dogs grouped according to the American College of Veterinary Internal Medicine (ACVIM) staging (group B1, n = 23; group B2, n = 27; group C + D, n = 48) and 46 healthy dogs.

METHODS

Multicenter prospective observational study. Serum and urine chemistry including NGAL reported as uNGAL concentration (uNGAL) and normalized with urinary creatinine (uNGALC) were compared between MMVD dogs and healthy controls, and among different MMVD ACVIM stages.

RESULTS

The MMVD dogs had significantly higher uNGAL and uNGALC (1204 pg/mL; range, 30-39 732 and 1816 pg/mg; range, 22-127 693, respectively) compared to healthy dogs (584 pg/mL; range, 56-4072 and 231 pg/mg; range, 15-2407, respectively; P = .002 and P < .0001, respectively). Both uNGAL and uNGALC increased with the increasing ACVIM stage (P = .001 and P < .001, respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Renal tubular damage is present in dogs with stable MMVD, as measured by increased uNGAL. This tubular damage is subclinical, occurs in all stages of MMVD even in the absence of azotemia, and increases with the severity of MMVD. Reno-protective approaches to manage MMVD dogs should be explored to slow the progression of renal tubular damage in these patients.

Effect of standard-dose and high-dose pimobendan on select indices of renal and cardiac function in dogs with American College of Veterinary Internal Medicine stage B2 myxomatous mitral valve disease

BACKGROUND

Pimobendan might have favorable effects on renal function but this has not been well-studied in dogs with myxomatous mitral valve disease (MMVD).

OBJECTIVES

Determine the effects of standard-dose (SD_pimo) and high-dose pimobendan (HD_pimo) on glomerular filtration rate (GFR) and cardiac size and function in dogs with preclinical MMVD.

ANIMALS

Thirty nonazotemic dogs with stage B2 MMVD.

METHODS

Prospective, randomized, double-blinded, placebo-controlled clinical study. Dogs had an echocardiographic examination, assessment of GFR (iohexol clearance), N-terminal probrain natriuretic peptide (NT-proBNP), and quality of life (QOL) score at baseline and 7 to 10 days after placebo (n = 6), SD_pimo 0.2 to 0.3 mg/kg q12 (n = 12), or HD_pimo 0.5 to 0.6 mg/kg q12h (n = 12).

RESULTS

No significant differences in GFR or QOL scores were detected between groups (P ≥ $$ \ge $$ .07). After HD_pimo, the mean [SD] percent change of NT_proBNP (-46.1 [20.2]%), left atrial volume (LAV; -27.1 [16.9]%), left ventricular end-diastolic volume (EDV; -21.8 [15.0]%), and end-systolic volume (ESV; -55.0 [20.7]%) were significantly different (P ≤ $$ \le $$ .004) from placebo (0.5 [19.9]%, 1.3 [15.6]%, -0.2 [8.2]%, -7.3 [35.6]%, respectively) but not the percent change after SD_pimo (-36.6 [16.1]%, -22.7 [14.9]%, -16.7 [12.5]%, -41.6 [14.8]%, respectively; P > .05). After SD_pimo, percent change of NT_proBNP, LAV, EDV, and ESV were significantly different from placebo (P < .05).

CONCLUSIONS AND CLINICAL IMPORTANCE

Results suggest that pimobendan (SD_pimo or HD_pimo) might not affect renal function in nonazotemic dogs with stage B2 MMVD. High-dose pimobendan did not demonstrate advantages over SD_pimo within the constraints of our study.

Plasmatic Dimethylarginines in Dogs With Myxomatous Mitral Valve Disease

Plasmatic dimethylarginines, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are considered biomarkers of endothelial and renal dysfunction, respectively, in humans. We hypothesize that plasmatic concentration of dimethylarginines in dogs with myxomatous mitral valve disease (MMVD) is influenced by heart disease stage. Eighty-five client-owned dogs with MMVD, including 39, 19, and 27 dogs in ACVIM stages B1, B2, and C+D, respectively, and a control group of 11 clinically healthy dogs were enrolled. A prospective, multicentric, case-control study was performed. Each dog underwent a complete clinical examination, arterial blood pressure measurement, thoracic radiography, six-lead standard electrocardiogram, transthoracic echocardiography, CBC, biochemical profile, and urinalysis. Plasmatic concentration of dimethylarginines was determined through high-performance liquid chromatography coupled with tandem mass spectrometry. Median ADMA was significantly increased in dogs of group C+D (2.5 μmol/L [2.1–3.0]) compared to those of group B1 (1.8 μmol/L [1.6–2.3]; p < 0.001) and healthy dogs (1.9 μmol/L [1.7–2.3]; p = 0.02). Median SDMA was significantly increased in dogs of group C+D (0.7 μmol/L [0.5–0.9]) compared to those of groups B1 (0.4 μmol/L [0.3–0.5]; p < 0.001), B2 (0.4 μmol/L [0.3–0.6]; p < 0.01), and the control group (0.4 μmol/L [0.35–0.45]; p = 0.001). In the final multivariable analysis, ADMA and SDMA were significantly associated with left atrium to aorta ratio (p < 0.001), and creatinine (p < 0.001), respectively. Increased plasmatic concentrations of dimethylarginines suggest a possible role as biomarkers of disease severity in dogs with decompensated MMVD.

Left atrial decompression as a palliative minimally invasive treatment for congestive heart failure caused by myxomatous mitral valve disease in dogs: 17 cases (2018-2019)

OBJECTIVE

To determine whether left atrial decompression (LAD) would reduce left atrial pressure (LAP) in dogs with advanced myxomatous mitral valve disease (MMVD) and left-sided congestive heart failure (CHF) and to describe the LAD procedure and hemodynamic alterations and complications.

ANIMALS

17 dogs with advanced MMVD and left-sided CHF that underwent LAD.

PROCEDURES

The medical record database was retrospectively reviewed for all LAD procedures attempted in dogs with MMVD and left-sided CHF between October 2018 and June 2019. Data were collected regarding signalment (age, breed, weight, and sex), clinical signs, treatment, physical examination findings, and diagnostic testing before and after LAD. Procedural data were also collected including approach, technique, hemodynamic data, complications, and outcome.

RESULTS

18 LAD procedures performed in 17 patients were identified. Dogs ranged in age from 7.5 to 16 years old (median, 11 years) and ranged in body weight from 2.9 to 11.6 kg (6.4 to 25.5 lb) with a median body weight of 7.0 kg (15.4 lb). Minimally invasive creation of an atrial septal defect for the purpose of LAD was successful in all dogs without any intraoperative deaths. Before LAD, mean LAP was elevated and ranged from 8 to 32 mm Hg with a median value of 14 mm Hg (reference value, < 10 mm Hg). Following LAD, there was a significant decrease in mean LAP (median decrease of 6 mm Hg [range, 1 to 15 mm Hg]). Survival time following LAD ranged from 0 to 478 days (median, 195 days).

CONCLUSIONS AND CLINICAL RELEVANCE

For dogs with advanced MMVD and left-sided CHF, LAD resulted in an immediate and substantial reduction in LAP.

Effect of spironolactone and benazepril on furosemide-induced diuresis and renin-angiotensin-aldosterone system activation in normal dogs

Background

Diuretic braking during furosemide continuous rate infusion (FCRI) curtails urine production.

Hypothesis

Renin‐angiotensin‐aldosterone system (RAAS) activation mediates braking, and RAAS inhibition will increase urine production.

Animals

Ten healthy purpose‐bred male dogs.

Methods

Dogs received placebo, benazepril, or benazepril and spironolactone PO for 3 days before a 5‐hour FCRI (0.66 mg/kg/h) in a 3‐way, randomized, blinded, cross‐over design. Body weight (BW), serum creatinine concentration (sCr), serum electrolyte concentrations, PCV, and total protein concentration were measured before PO medications, at hours 0 and 5 of FCRI, and at hour 24. During the FCRI, water intake, urine output, urine creatinine concentration, and urine electrolyte concentrations were measured hourly. Selected RAAS components were measured before and after FCRI. Variables were compared among time points and treatments.

Results

Diuretic braking and urine production were not different among treatments. Loss of BW, hemoconcentration, and decreased serum chloride concentration occurred during FCRI with incomplete recovery at hour 24 for all treatments. Although unchanged during FCRI, sCr increased and serum sodium concentration decreased at hour 24 for all treatments. Plasma aldosterone and angiotensin‐II concentrations increased significantly at hour 5 for all treatments, despite suppressed angiotensin‐converting enzyme activity during benazepril background treatment.

Conclusions

The neurohormonal profile during FCRI supports RAAS mediation of diuretic braking in this model. Background treatment with benazepril with or without spironolactone did not mitigate braking, but was well tolerated. Delayed changes in sCr and serum sodium concentration and incomplete recovery of hydration indicators caused by furosemide hold implications for clinical patients.

Red Cell Distribution Width Has a Negative Prognostic Role in Dogs with Myxomatous Mitral Valve Disease

Simple Summary

The red cell distribution width (RDW) is a simple and inexpensive laboratory parameter that reflects the difference in size of the red blood cells (also known as anisocytosis) and is conventionally used in a clinical setting for the differential diagnosis of anemias. Nonetheless, recent studies have demonstrated that anisocytosis is commonplace in many non-hematological human disorders and an increased RDW has been associated with a negative prognosis in patients with different cardiovascular diseases. In dogs, no studies have evaluated the prognostic role of RDW with myxomatous mitral valve disease (MMVD). The present study evaluates clinical, echocardiographic, and laboratory parameters, including RDW, with a cohort of dogs with MMVD and followed up on for more than one year. We sought to evaluate if RDW acts as an independent prognostic marker for negative outcomes in dogs with MMVD with or without concurrent non-cardiac diseases.

Abstract

Red cell distribution width (RDW) is a quantitative measurement of anisocytosis. This hematological parameter is an important prognostic biomarker for different cardiovascular disorders in humans but its influence on survival has been poorly investigated in dogs with cardiovascular disease. The RDW and various clinical, complete blood count, serum biochemical and echocardiographic variables were retrospectively investigated in 146 client-owned dogs with myxomatous mitral valve disease (MMVD) at various disease stages, with or without concurrent diseases and treatment. Laboratory variables, including RDW, urea, and white blood cell (WBC), in addition to the echocardiographic variable left atrium to aorta ratio were found to be independent predictors of all-cause mortality at six months in a multivariable Cox proportional hazards regression model. In particular, the hazard ratio of RDW was 1.203 (95% confidence interval = 1.045–1.384; p = 0.010). The negative effect of increased RDW on outcome was confirmed using Kaplan–Meier curve analysis. The results of this study indicate that RDW acted as an independent predictor of negative outcome in dogs with MMVD.

The effect of myxomatous mitral valve disease severity on packed cell volume in dogs

OBJECTIVES

The aim of this study was to examine whether associations between disease severity and packed cell volume exist in dogs with myxomatous mitral valve disease.

MATERIALS AND METHODS

Data were selected from 289 dogs that had been examined at a research clinic (2004-2017) on multiple occasions (n=1465). American College of Veterinary Internal Medicine stage and echocardiographic measurements were entered in separate multivariable linear mixed effects models with packed cell volume as the dependent variable. Age, breed, sex, weight and blood urea nitrogen concentrations were additionally tested in these analyses to control for patient characteristics.

RESULTS

Packed cell volume (% whole blood) in stages B1 and B2 (B1: 42.62 ±0.27, P=0.001; B2: 41.77± 0.42, P < 0.001) was lower than stage A (44.57 ±0.53). In stage C, packed cell volume was greater than both preclinical stages (C: 43.84 ±0.46). When the administration of loop diuretics was included in statistical models, packed cell volume was inversely related to normalised left ventricular internal diameters (β: -2.37; 95% confidence intervals: -3.49, -1.25; P < 0.001).

CLINICAL SIGNIFICANCE

Dogs with myxomatous mitral valve disease may develop reductions in packed cell volume as their disease progresses. Although this finding was statistically significant at a population level, it should be noted that the differences described are relatively small. This, along with other causes of variation in packed cell volume, means that changes would be challenging to appreciate within individual patients. Plasma volume depletion following diuretic administration may explain why findings differed in stage C.

Evaluation of red blood cell profiles in dogs with heartworm disease

Recent studies have found that anemia and anisocytosis are precipitating factors for certain heart diseases in dogs. This study evaluated the prevalence and correlation of anemia and red blood cell distribution width (RDW) in dogs with heartworm disease (HWD). The study population consisted of 20 healthy control dogs and 86 dogs with HWD: 28 dogs with no clinical signs or pulmonary hypertension (Group 1), 42 dogs with mild clinical signs but no pulmonary hypertension (Group 2), and 16 dogs with severe clinical signs and pulmonary hypertension (Group 3). Along with echocardiographic interrogation of pulmonary hypertension, red blood cell (RBC) profiles were evaluated, including RDW. The total number of red blood cells (tRBCs), hematocrit (HCT), and hemoglobin (HGB) concentration was significantly lower in Group 3 dogs compared to control dogs (P < 0.05), while the RDW was significantly higher in Group 3 dogs than in control dogs (P < 0.05). The RDW was closely correlated to other RBC profiles and the presence of pulmonary hypertension (P < 0.05). The severity of tricuspid regurgitant gradient (TRG) was closely correlated with Hb and tRBC (P < 0.05), but not with the RDW and reticulocyte count. This study finding indicated that anemia and anisocytosis are common complications in dogs with severe clinical signs and pulmonary hypertension caused by heartworm disease (HWD). It would therefore be beneficial for clinicians to routinely check red blood cell (RBC) profiles, including RDW, in order to monitor the progression of heartworm disease in dogs.

Hypertension, retinopathy, and acute kidney injury in dogs: A prospective study

BACKGROUND

Systemic hypertension (SH) is a potential complication of acute kidney injury (AKI) in dogs.

OBJECTIVE

To describe the prevalence of SH and hypertensive retinopathy in dogs with AKI, to investigate the relationship between SH and severity of AKI and to assess possible factors associated with SH.

ANIMALS

Fifty-two dogs with AKI.

METHODS

Prospective observational study of dogs presenting to a tertiary referral center that fulfilled the International Renal Interest Society (IRIS) guidelines for the diagnosis of AKI. Systolic blood pressure measurement, urine protein/creatinine ratio (UPCR), urine output, presence of hypertensive retinopathy and fluid overload (FO), survival to discharge and duration of hospitalization were subsequently assessed. The prevalence of SH was calculated and the relationship between SH and recorded factors was examined by nonparametric statistics.

RESULTS

The prevalence of SH (≥160 mm Hg) on admission or during hospitalization was 75% (39/52) and in 56% (22/39) of cases this was severe (≥180 mm Hg). Sixteen percent (7/43) of dogs had evidence of hypertensive retinopathy and 77% (24/31) dogs had UPCR >0.5. Forty-two percent (22/52) dogs had FO on admission or during hospitalization. There was no association between SH and IRIS AKI grade, oligo/anuria, survival to discharge, duration of hospitalization or proteinuria. Dogs with FO on presentation were more likely to be hypertensive at admission compared to dogs without FO (P = .02). Dogs that did not survive to discharge were more likely to have FO (P = .007).

CONCLUSIONS AND CLINICAL IMPORTANCE

Systemic hypertension is common in dogs with AKI. Systemic hypertension might be associated with FO, which itself is associated with nonsurvival. Monitoring for SH and FO is therefore warranted in dogs with AKI.

Symmetric dimethylarginine in dogs with myxomatous mitral valve disease at various stages of disease severity

Symmetric dimethylarginine (SDMA) is a serum biomarker of renal damage in dogs. Moreover, SDMA concentration is an independent predictor of development of severe heart failure (HF) in humans with cardiac disease. This study evaluates whether the serum concentration of SDMA in dogs with myxomatous mitral valve disease (MMVD) is influenced by the severity of heart disease, pulmonary hypertension (PH) and treatment of HF. A total of 99 client-owned dogs were included in this retrospective case-control study; 78 dogs were affected by MMVD and classified according to the American College of Veterinary Internal Medicine (ACVIM) guidelines, and 21 were healthy controls. For each dog, history, physical examination, complete blood count, biochemical profile, thoracic radiography, 6-lead standard electrocardiogram and trans-thoracic echocardiography were available. Comparisons were performed between groups of dogs belonging to different ACVIM stages and between dogs with and without PH. The median SDMA concentration was neither significantly different among groups of dogs in different disease stages (overall P = 0.010), nor among dogs with MMVD, nor between those with [14.5 μg/dl (10.5–18.8)] and without PH [13 μg/dl (9–17.2)] (P = 0.295). The concentration of SDMA did not differ between dogs when considering the combined effect of the ACVIM group and cardiac treatment (overall P = 0.486). Furthermore, no correlation was found between SDMA concentration and radiographic and echocardiographic parameters associated with increased MMVD severity. In conclusion, this study failed to demonstrate the presence of renal impairment in dogs with MMVD, and the increase in renal parameters in some dogs in the more advanced stage of MMVD could be attributed to pre-renal azotemia.

Canine Traditional Laboratory Tests and Cardiac Biomarkers

In small animals, cardiac disease evaluation through laboratory tests can be a challenge. This review will present both historical and updated perspectives on the clinical pathology of cardiac diseases in dogs and demonstrate that laboratory tests are useful tools for the management of patients with cardiac diseases.

Cardiovascular-renal axis disorder and acute-phase proteins in cats with congestive heart failure caused by primary cardiomyopathy

BACKGROUND

Currently, the pathogenesis of congestive heart failure (CHF) in cats is not fully understood.

OBJECTIVE

To identify novel biomarkers for CHF in cats caused by primary cardiomyopathy, particularly related to cardiovascular-renal axis disorder and systemic inflammatory response.

ANIMALS

Twenty-five cats in CHF caused by primary cardiomyopathy, 12 cats with preclinical cardiomyopathy, and 20 healthy controls.

METHODS

Case control and observational case series. The following serum biomarkers were compared among the 3 cat groups: a cardiorenal profile that included N-terminal pro-brain natriuretic peptide (NT-proBNP), symmetric dimethylarginine (SDMA), and creatinine and an inflammatory profile that included 7 acute-phase proteins (APPs). Survival analyses and longitudinal studies were performed in CHF cats.

RESULTS

All cardiorenal biomarkers were positively correlated and higher in CHF cats, and high NT-proBNP and SDMA were associated with poor clinical outcome. Cats with CHF had significantly higher leucine-rich alpha-2-glycoprotein 1, serum amyloid A, and ceruloplasmin, and these APPs were positively correlated with NT-proBNP and left atrial size. In a multivariable survival analysis, alpha-1-acid glycoprotein concentration (P = .01), body weight (P = .02) and left atrial-to-aortic root ratio (P = .01) were independent prognostic factors for CHF in these cats.

CONCLUSIONS AND CLINICAL IMPORTANCE

In cats, CHF is an inflammatory disorder and outcome in CHF may be determined by the extent of inflammation and possibly the amount of residual renal function. These novel biomarkers have potential use for the clinical management, prognosis, and future research into CHF and cardiomyopathy in cats.

Measurements of echocardiographic indices and biomarkers of kidney injury in dogs with chronic kidney disease

Pathophysiological cardiac and renal interactions are termed cardiovascular-renal disorder (CvRD). Cardiovascular disease/dysfunction secondary to kidney disease (CvRD_K), is a leading cause of death in human chronic kidney disease (CKD) patients. The presence and clinical impact of CvRD_K in dogs with CKD is unknown. We hypothesized that echocardiographic measurements, and cardiac and renal biomarkers, will be altered in dogs with CKD and associated with survival. Eleven dogs with CKD (n = 6 IRIS stage 2, n = 5 IRIS stage 3) and without primary cardiac disease, plus 12 healthy age-matched control dogs, were recruited to this prospective observational study. Dogs underwent standard echocardiography, glomerular filtration rate (GFR) estimation by iohexol clearance, and measurement of plasma cardiac troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP), plasma and urinary cystatin B, and urinary clusterin and neutrophil gelatinase-associated lipocalin (NGAL). Values were compared between groups, and their association with all-cause mortality explored. Dogs with CKD had significantly lower GFR and higher NT-proBNP, urinary cystatin B, clusterin, and NGAL, compared to controls (P < 0.05). Echocardiographic measurements were similar between dogs with CKD and controls. Median follow-up time was 666 days, during which six dogs with CKD died. Risk of death was associated with increasing age, serum total protein, and normalized left ventricular posterior wall thickness (LVPWDN) and decreasing bodyweight and packed cell volume. Although baseline differences in echocardiographic measurements were not evident between dogs with moderate CKD and controls, the presence of CvRD_K was suggested by the association between LVPWDN and survival.

Role of electrolyte concentrations and renin-angiotensin-aldosterone activation in the staging of canine heart disease

Background

Refractory congestive heart failure (CHF) and associated diuretic resistance are not well defined.

Objectives

To characterize renal function, electrolyte concentrations, indices of diuretic efficacy, and renin‐angiotensin‐aldosterone system (RAAS) activation in dogs with naturally occurring heart disease (HD) in American College of Veterinary Internal Medicine stages B1, B2, C, and D and to determine their usefulness in defining HD stages.

Animals

Group 1:149 dogs with HD stages B1, B2, C, and D. Group 2:22 dogs with HD stages C and D.

Methods

Group 1: Renal parameters, serum and urine electrolyte and diuretic concentrations, and urine aldosterone concentrations were measured. Medication dosages and measured variables were compared among stages. Correlation of furosemide dosages to serum concentrations was explored. Group 2: Angiotensin‐converting enzyme activity and RAAS components were measured and compared among CHF stages.

Results

Serum chloride concentration was the best differentiator of HD stage. Furosemide PO dosages (≤6 mg/kg/day) were weakly correlated with serum furosemide concentrations, whereas higher dosages were not significantly correlated. Angiotensin‐converting enzyme inhibitor dosage and RAAS inhibition were greater in stage D, compared to stage C dogs.

Conclusions and Clinical Importance

Hypochloremia is a useful marker for stage D HD in dogs. Poor furosemide dosage correlation to serum concentration may indicate variable and poor absorption, especially at higher dosages, advanced disease, or both. A small number of stage D dogs met proposed criteria for diuretic resistance. Greater RAAS inhibition in stage D versus stage C indicates effectiveness of RAAS‐suppressive treatments in this group of dogs with refractory CHF.

Prognostic factors in dogs with presumed degenerative mitral valve disease attending primary-care veterinary practices in the United Kingdom

Background

Prognostic risk factors were identified for dogs with degenerative mitral valve disease (DMVD) monitored by veterinary cardiologists. The value of these measurements has not been determined in the wider primary care setting.

Objectives

To evaluate whether plasma cardiac biomarkers and data obtained from routine history‐taking and physical examination are predictive of survival in dogs with DMVD attending primary care practice.

Animals

Eight‐hundred and ninety‐three dogs with a presumptive diagnosis of DMVD recruited from 79 primary care veterinary practices in the United Kingdom.

Methods

Prospective cohort study. Primary care veterinary practitioners recorded clinical data. Plasma N‐terminal pro B‐type natriuretic peptide (NT‐proBNP) and cardiac troponin I (cTnI) were measured at presentation. Cox regression models evaluated associations between risk factor variables and hazard of death (all‐cause mortality and cardiac‐related death). Flexible parametric models generated predicted survival probabilities for dogs with different combinations of prognostic risk factor variable values.

Results

Dogs with higher NT‐proBNP and cTnI concentrations, higher heart rates, older dogs, females, and those reported to be exercise intolerant, dyspneic, and diagnosed with selected comorbidities had an increased hazard of death due to any cause. Dogs with higher concentrations of plasma biomarkers, higher heart rates, and heart murmur intensities, those with exercise intolerance and those receiving potent diuretics had a higher hazard of cardiac‐related death.

Conclusions and Clinical Importance

Cardiac biomarkers and key clinical findings identified in this study can help primary care veterinary practitioners identify dogs with DMVD that are at highest risk of death.

Reliability of symmetric dimethylarginine in dogs with myxomatous mitral valve disease as kidney biomarker

The most common cause of heart failure in the canine population is myxomatous mitral valve disease, sometimes complicated by chronic kidney disease. Many studies have been done on the use of symmetric dimethylarginine as biomarker of renal impairment in dogs affected by chronic kidney disease, few studies have examined his reliability as biomarker in dogs affected by heart diseases. Aim of this study was to evaluate symmetric dimethylarginine in dogs affected by mitral valve disease in order to assess his reliability in heart diseases. This was a retrospective case-control study on a clinical population of dogs affected by mitral valve disease (cases) vs healthy dogs (controls). Both groups underwent a complete physical evaluation, echocardiographic examination, complete blood count, biochemical panel, including serum creatinine and urea and urine analysis with protein-to-creatinine ratio. Serum was frozen and sent to IDEXX laboratories for symmetric dimethylarginine determination. General linear model was applied to data. A total number of 24 cases and 7 controls were included. Symmetric dimethylarginine value was in the reference value in the 75% (n=18) of cases, and in the 43% (n=3) of controls. Once set symmetric dimethylarginine as dependent variable, no statistical significant differences were found for each variable considered (breed, age, sex, weight, class of cardiomyopathy, presence/absence of valvular disease, presence/absence of congestive heart failure, pharmacological therapy, creatinine and urea concentration). Blood concentration of SDMA resulted not influenced by the variables mentioned above, so it could be considered a reliable marker of early renal impairment in dogs affected by mitral valve disease.

Evaluation of serum neutrophil gelatinase-associated lipocalin as a novel biomarker of cardiorenal syndrome in dogs

Worsening renal function and azotemia in patients with heart failure (HF) are strongly associated with disease severity and poor prognosis. Increasing interest in this correlation led to the description and classification of cardiorenal syndrome (CRS). We evaluated the role of neutrophil gelatinase-associated lipocalin (NGAL) in the early detection of CRS in dogs with HF. Ten healthy dogs and 31 dogs admitted with HF were included in our study. NGAL and troponin-I were measured on samples collected on the day of admission; creatinine was measured on admission and again on day 7. The CRS group was defined as subsequently developing renal azotemia. Of 31 dogs with HF, 20 were included in the HF group, and 11 were included in the CRS group. The admission NGAL concentrations of the CRS group were significantly higher than those of other groups ( p < 0.001). The severity of HF evaluation based on the modified New York Heart Association classification showed significant correlation with NGAL ( p < 0.001) and troponin-I ( p = 0.009) concentration. However, only serum NGAL concentration at admission was significantly associated with the development of CRS in dogs with HF ( p = 0.021). The admission serum NGAL ≥ 16.0 ng/mL (optimal cutoff value) had a sensitivity of 90.9% and specificity of 90.0% in predicting the development of CRS.

Cardiorenal Syndrome: Diagnosis and Management

Cardiorenal syndrome (CRS) has not been well characterized in veterinary medicine, yet an accurate appreciation of the kidney and the cardiovascular system and their interactions may have practical clinical implications. A consensus for cardiovascular-renal axis disorders of dogs and cats was recently attempted. The outcome of patients with CRS is likely to improve with the increasing awareness and ability to identify and understand the pathophysiologic characteristics of CRS. The utilization of existing and emerging organ-specific biomarkers with greater sensitivities than conventional diagnostics forecast new opportunities to diagnose and manage cardiac disease.