International Renal Interest Society best practice consensus guidelines for the diagnosis and management of acute kidney injury in cats and dogs

Acute kidney injury (AKI) is defined as an injury to the renal parenchyma, with or without a decrease in kidney function, as reflected by accumulation of uremic toxins or altered urine production (i.e., increased or decreased). AKI might result from any of several factors, including ischemia, inflammation, nephrotoxins, and infectious diseases. AKI can be community- or hospital-acquired. The latter was not previously considered a common cause for AKI in animals; however, recent evidence suggests that the prevalence of hospital-acquired AKI is increasing in veterinary medicine. This is likely due to a combination of increased recognition and awareness of AKI, as well as increased treatment intensity (e.g., ventilation and prolonged hospitalization) in some veterinary patients and increased management of geriatric veterinary patients with multiple comorbidities. Advancements in the management of AKI, including the increased availability of renal replacement therapies, have been made; however, the overall mortality of animals with AKI remains high. Despite the high prevalence of AKI and the high mortality rate, the body of evidence regarding the diagnosis and the management of AKI in veterinary medicine is very limited. Consequently, the International Renal Interest Society (IRIS) constructed a working group to provide guidelines for animals with AKI. Recommendations are based on the available literature and the clinical experience of the members of the working group and reflect consensus of opinion. Fifty statements were generated and were voted on in all aspects of AKI and explanatory text can be found either before or after each statement.

Updated ACVIM consensus statement on leptospirosis in dogs

Since publication of the last consensus statement on leptospirosis in dogs, there has been revision of leptospiral taxonomy and advancements in typing methods, widespread use of new diagnostic tests and vaccines, and improved understanding of the epidemiology and pathophysiology of the disease. Leptospirosis continues to be prevalent in dogs, including in small breed dogs from urban areas, puppies as young as 11 weeks of age, geriatric dogs, dogs in rural areas, and dogs that have been inadequately vaccinated for leptospirosis (including dogs vaccinated with 2-serovar Leptospira vaccines in some regions). In 2021, the American College of Veterinary Internal Medicine (ACVIM) Board of Regents voted to approve the topic for a revised Consensus Statement. After identification of core panelists, a multidisciplinary group of 6 experts from the fields of veterinary medicine, human medicine, and public health was assembled to vote on the recommendations using the Delphi method. A draft was presented at the 2023 ACVIM Forum, and a written draft posted on the ACVIM website for comment by the membership before submission to the editors of the Journal of Veterinary Internal Medicine. This revised document provides guidance for veterinary practitioners on disease in dogs as well as cats. The level of agreement among the 12 voting members (including core panelists) is provided in association with each recommendation. A denominator lower than 12 reflects abstention of ≥1 panelists either because they considered the recommendation to be outside their scope of expertise or because there was a perceived conflict of interest.

Biochemical, electrolytic, and cardiovascular evaluations in cats with urethral obstruction

Background and Aim:

Urethral obstruction (UO) is a common condition in feline medicine. Severe acid-base and electrolyte disorders promote relevant electrocardiographic changes in these animals. Cardiac biomarkers such as cardiac troponin I have been shown to be useful in identifying cats with myocardial disease, but it has not been investigated whether UO leads to myocardial damages. This study aimed to evaluate biochemical changes, electrocardiographic findings, troponin I measurements, and electrolyte disturbances for 7 days in cats with UO.

Materials and Methods:

This follow-up prospective study included 33 cats diagnosed with UO for 7 days. For all cats, clinical examination, serum biochemistry, electrolyte analyses, blood pressure, and electrocardiography were performed. Cardiac troponin I was measured in the serum in 16 cats at 3 different times.

Results:

The mean age of the feline population was 1.83±1.58 years (mean±standard deviation). Creatinine, urea, blood urea nitrogen, glucose, phosphorus, base excess, bicarbonate, and serum potassium decreased significantly (p≤0.05), while ionic calcium and blood pH increased significantly (p≤0.05) at different times. Electrocardiographic abnormalities were observed in 21/33 (63.63%) of the felines on admission day. The electrocardiographic abnormalities were no longer observed on the subsequent days. Only one feline showed changes in troponin I cardiac concentrations.

Conclusion:

This study suggests the sum and severity of electrolyte abnormalities aggravate the clinical and cardiovascular status of these patients. However, cTnI, blood pressure, and heart rate within the reference range do not exclude the presence of major cardiovascular and metabolic abnormalities. The hyperglycemia in felines with UO appears to be associated with decreased renal clearance, which may reflect the severity of hyperkalemia and azotemia. The metabolic and cardiovascular changes of these felines are minimized by the establishment of appropriate intensive care; however, cardiac and blood gas monitoring is essential to assess the severity of the disease.

Clinical-pathological and immunohistochemical evaluations of cardiac lesions in cats with chronic kidney disease

ABSTRACT: Chronic kidney disease (CKD) is characterized by irreversible morphostructural lesions that can progressively evolve to chronic renal insufficiency and kidney failure. It is known that the heart and kidneys are closely related, and that communication between these organs occurs through a variety of pathways; subtle physiological changes in one of them are compensated by the other. Histopathological cardiac evaluation through routine staining presents a limitation to identify specific or discreet lesions in the cardiomyocytes. This study aimed to evaluate serum troponin levels in cats with CKD, associated with clinical and pathological findings, as well as to correlate the morphostructural cardiac lesions to determine their distribution through macroscopic and histological assessments and anti-cardiac troponin C (cTnC) immunohistochemistry (IHC). To this end, 20 cats (18 diagnosed with CKD and two controls) were selected. Anti-human cTnC IHC was conducted after necropsy and separation in eight regions of each collected heart. Heart fragments from two cats without CKD were used as controls. The anti-human cTnC antibody is useful in detecting cardiac lesions and has shown decreased expression in cardiomyocytes of cats with CKD. Serum troponin was above the reference values in 11/18 (61.11%) animals and decreased expression for the cTnC antibody was observed in individual cardiomyocytes in 9/18 (50%) animals. It was verified that the number of regions with decreased expression for the cTnC antibody in cardiomyocytes is significantly correlated with serum troponin. The anti-human cTnC antibody has been found effective in detecting cardiac lesions and has shown decreased expression in the cardiomyocytes of cats with CKD. Correlation was observed between increased serum cTnI and loss of immunoreactivity at anti-cTnC antibody IHC in cats with CKD, which proves damage to cardiomyocytes secondary to kidney disease.

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.

Cardiac troponin I in cats with compromised renal function

OBJECTIVES

Cardiac troponins are sensitive and specific markers of myocardial injury. However, their reliability in renal disease has been questioned owing to possible renal involvement in troponin elimination. The primary objective of the present study was to examine whether serum cardiac troponin I is elevated in cats with compromised renal function and no clinically relevant structural cardiac disease. A secondary objective was to examine whether cardiac troponin I is measurable in the urine of cats with normal and compromised renal function.

METHODS

This prospective case-control study included 52 cats (19 with compromised renal function, 19 with primary cardiac disease and 14 healthy controls). For all cats, clinical examination, echocardiography, electrocardiography, blood pressure, complete blood count, biochemistry, serum thyroxine and urinalysis were performed. Cardiac troponin I was measured in the serum and urine of each cat.

RESULTS

Median (range) serum cardiac troponin I concentrations were 0.052 ng/ml (0.015-0.78 ng/ml) for the renal group, 0.083 ng/ml (0.003-3.27 ng/ml) for the cardiac group and 0.012 ng/ml (0.003-0.14 ng/ml) for the control group. The renal and cardiac groups both had significantly higher serum cardiac troponin I concentrations than the control group, whereas no difference could be detected between the renal and cardiac groups. In the renal group 7/19 cats had measurable urine cardiac troponin I, whereas cardiac troponin I was measurable in the urine of one cat in the cardiac group and two healthy controls. There was no significant correlation between serum and urine cardiac troponin I.

CONCLUSIONS AND RELEVANCE

Elevated serum cardiac troponin I in cats with compromised renal function may occur without evidence of clinically relevant structural cardiac disease. Moreover, detecting cardiac troponin I in urine is most likely in cats with compromised renal function.

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.