Clinical relevance of serum electrolytes in dogs and cats with acute heart failure: A retrospective study

Correlation of serum chloride concentrations with components of the renin-angiotensin-aldosterone system in a dog with congestive heart failure

A 7-year-old male castrated Cavalier King Charles Spaniel was hospitalized for 12 days for treatment of severe congestive heart failure secondary to myxomatous mitral valve disease. During that time, 6 serum samples from different days were analyzed for serum biochemical and renin-angiotensin-aldosterone system components. Serum chloride concentrations (ranging from 71.6 to 103.1 mmol/L) were inversely related to angiotensin I concentrations, aldosterone concentrations, a surrogate marker of renin activity, and a surrogate marker of adrenal responsiveness to angiotensin II. In light of recent studies showing that hypochloremia is associated with advanced heart failure in dogs and is associated with poor outcomes in people, the information from the dog in this report supports exploration of RAAS dysregulation as an underlying mechanism.

Occurrence of cardiovascular events in 168 cats with acute urinary tract obstruction

Background

Cardiovascular dysfunction associated with acute kidney injury has been recently described in veterinary medicine, but limited information is available for cats with urinary tract obstruction (UTO).

Objective

This retrospective study aimed to describe the type, frequency, timeline, and risk factors for cardiovascular events (CVEs) in cats treated for acute UTO.

Animals and procedures

Medical records of cats admitted to the intensive care unit for either upper (ureteral: UUTO) or lower (urethral: LUTO) UTO from 2016 to 2021 were reviewed. Cardiovascular events were defined as development of arrhythmia, heart murmur or gallop sound, clinical signs consistent with fluid overload (CRFO), or decreased tissue perfusion (DTP).

Results

One hundred and sixty-eight cats with UTO were recruited (56 with UUTO and 112 with LUTO). Cardiovascular events were reported in 61.9% of cases, including arrhythmia (33.6%), gallop rhythm (28.1%), heart murmur (15.3%), CRFO (14.4%), and DTP (8.6%). Potassium concentration, preexisting chronic kidney disease, and renal pelvic dilation at abdominal ultrasonography were associated with CVE occurrence in multivariate analysis.

Conclusions

This study highlighted frequent CVEs in cats treated for UTO, with a potential strong impact on outcome. Therefore, cardiovascular parameters of cats with preexisting chronic kidney disease or those admitted with hyperkalemia or renal pelvic dilation should be closely monitored.

Clinical relevance of serum ionized magnesium concentration in dogs with myxomatous mitral valve disease

BACKGROUND

Hypomagnesemia is associated with a poor prognosis in humans with congestive heart failure (CHF), but studies in veterinary medicine are limited.

HYPOTHESIS

Serum ionized magnesium concentration [iMg2+ ] would decrease as CHF progresses compared with the initial diagnostic levels and that lower [iMg2+ ] would be negatively associated with prognosis in dogs with CHF.

ANIMALS

A total of 181 client-owned dogs with myxomatous mitral valve disease (MMVD) were included. They were classified into the preclinical stage (NO-CHF, n = 108), stage C (n = 42), and stage D (n = 31) based on the American College of Veterinary Internal Medicine MMVD classification.

METHODS

This is a retrospective study from 2 referral centers. The [iMg2+ ] was compared among the NO-CHF, stage C, and stage D groups. Kaplan-Meier curves and the log-rank test were used to compare the incidence of death between groups. Multivariable Cox regression analysis was used to estimate the association of hypomagnesemia with the death.

RESULTS

In the stage D group, the [iMg2+ ] was lower than that in the NO-CHF (P < .0001) and stage C groups (P < .003). In the Kaplan-Meier survival analysis, the 1-year cumulative survival rate in hypomagnesemic dogs was 53% compared with 91.5% in normomagnesemic dogs (log-rank test, P < .0001). In the multivariable Cox analysis, lower concentration of [K+ ] and [iMg2+ ], along with higher Evel , were associated with negative prognoses. Specifically, hypomagnesemia was associated with an approximately 4-fold increased risk of death (hazard ratio = 4.015; 95% confidence interval, 1.537-10.488; P = .005).

CONCLUSIONS AND CLINICAL IMPORTANCE

Assessing the [iMg2+ ] might serve as a potential marker for estimating the severity and prognosis indirectly in dogs with MMVD. Combining [iMg2+ ] measurement with other diagnostic methods, such as echocardiography, could improve the prognostic evaluation of MMVD in dogs.

Machine learning-based risk prediction model for canine myxomatous mitral valve disease using electronic health record data

Introduction

Myxomatous mitral valve disease (MMVD) is the most common cause of heart failure in dogs, and assessing the risk of heart failure in dogs with MMVD is often challenging. Machine learning applied to electronic health records (EHRs) is an effective tool for predicting prognosis in the medical field. This study aimed to develop machine learning-based heart failure risk prediction models for dogs with MMVD using a dataset of EHRs.

Methods

A total of 143 dogs with MMVD between May 2018 and May 2022. Complete medical records were reviewed for all patients. Demographic data, radiographic measurements, echocardiographic values, and laboratory results were obtained from the clinical database. Four machine-learning algorithms (random forest, K-nearest neighbors, naïve Bayes, support vector machine) were used to develop risk prediction models. Model performance was represented by plotting the receiver operating characteristic (ROC) curve and calculating the area under the curve (AUC). The best-performing model was chosen for the feature-ranking process.

Results

The random forest model showed superior performance to the other models (AUC = 0.88), while the performance of the K-nearest neighbors model showed the lowest performance (AUC = 0.69). The top three models showed excellent performance (AUC ≥ 0.8). According to the random forest algorithm's feature ranking, echocardiographic and radiographic variables had the highest predictive values for heart failure, followed by packed cell volume (PCV) and respiratory rates. Among the electrolyte variables, chloride had the highest predictive value for heart failure.

Discussion

These machine-learning models will enable clinicians to support decision-making in estimating the prognosis of patients with MMVD.

The Prognostic Utility of Venous Blood Gas Analyses at Presentation in Cats with Cardiogenic Pulmonary Edema

Cats urgently visit emergency hospitals due to respiratory distress, and the chief cause is cardiogenic pulmonary edema (CPE). Although cats with CPE were frequently encountered in clinics, the prognostic factors were poorly reported. The objective of this retrospective study was to investigate the association of physical examination and venous blood gas parameters with the survival of cats with CPE in an emergency hospital. Thirty-six cats with CPE were ultimately included in the present study, and eight of them died within 12 h after their presentation to our hospital. Statistical analyses of clinical parameters between cats that died within 12 h and those that survived for 12 h were conducted using Mann-Whitney U test with Bonferroni correction. Cats that died within 12 h had significantly lower rectal temperatures and higher PvCO₂ than those that did not die within 12 h. Moreover, hypotension and vasoconstrictor use were related to death within 12 h of presentation and higher PvCO₂. These findings indicated the prognostic utility of body temperature and PvCO₂, and the association between hypercapnia and the severity of CPE or hypotension. A large number of prospective studies should be performed to validate these results.

Toward quantification of loop diuretic responsiveness for congestive heart failure

Diuretics, such as furosemide, are routinely administered to dogs with congestive heart failure (CHF). Traditionally, dose and determination of efficacy primarily are based on clinical signs rather than quantitative measures of drug action. Treatment of human CHF patients increasingly is guided by quantification of urine sodium concentration (uNa) and urine volume after diuretic administration. Use of these and other measures of diuretic responsiveness is associated with decreased duration of hospitalization, complication rates, future rehospitalization, and mortality. At their core, loop diuretics act through natriuresis, and attention to body sodium (Na) stores and handling offers insight into the pathophysiology of CHF and pharmacology of diuretics beyond what is achievable from clinical signs alone. Human patients with low diuretic responsiveness or diuretic resistance are at risk for difficult or incomplete decongestion that requires diuretic intensification or other remedial strategies. Identification of the specific etiology of resistance in a patient can help tailor personalized interventions. In this review, we advance the concept of loop diuretic responsiveness by highlighting Na and natriuresis. Specifically, we review body water homeostasis and congestion in light of the increasingly recognized role of interstitial Na, propose definitions for diuretic responsiveness and resistance in veterinary subjects, review relevant findings of recent studies, explain how the particular cause of resistance can guide treatment, and identify current knowledge gaps. We believe that a quantitative approach to loop diuretic usage primarily involving natriuresis will advance our understanding and care of dogs with CHF.

Retrospective evaluation of risk factors for development of kidney injury after parenteral furosemide treatment of left-sided congestive heart failure in dogs

BACKGROUND

Kidney injury (KI) has been documented in dogs treated with furosemide for left-sided congestive heart failure (CHF).

HYPOTHESIS/OBJECTIVES

Determine risk factors for development of KI in furosemide-treated dogs and determine the effect of KI on survival.

ANIMALS

Seventy-nine client-owned dogs receiving parenteral furosemide for CHF.

METHODS

Serum creatinine (sCr) and electrolyte concentrations were determined during hospitalization and at first outpatient reevaluation to detect and stage KI (increase in sCr ≥0.3 mg/dL). Furosemide dosage administered between timepoints was calculated. Multivariable modeling was performed to identify predictors of KI and percent change in serum biochemistry results over time.

RESULTS

Kidney injury was identified in 38/79 (48%) dogs and mostly occurred during hospitalization. Kidney injury was Grade I in 25 dogs, Grade II in 9 dogs, and Grade III in 4 dogs. Higher blood pressure was associated with acute KI during hospitalization (odds ratio, 1.03; 95% confidence interval [95% CI] 1.01-1.07; P = .03) whereas PO furosemide dosage was associated with KI after hospital discharge (odds ratio, 7.77; 95% CI, 2.05-68.6; P = .02). Baseline sCr and use of a furosemide continuous rate infusion were not associated with increased risk of KI. Kidney injury was not associated with long-term outcome. Of 13 dogs with Grade II-III KI, azotemia was reversible in 9 dogs, and 6 dogs survived >1 year after KI.

CONCLUSIONS AND CLINICAL IMPORTANCE

In this cohort of dogs receiving parenteral furosemide for CHF, KI was common, mostly nonazotemic (Grade I), and did not impact survival.

Serum Chloride Is Inversely Associated With 3 Months Outcomes in Chinese Patients With Heart Failure, a Retrospective Cohort Study

Background

Serum chloride was recently found to be associated with prognosis of heart failure in western countries. However, the evidence was scarce in Asia. We aimed to investigated the relationship between serum chloride and clinical outcomes in a Chinese cohort with hospitalized heart failure.

Methods

We retrospectively analyzed the data from PhysioNet, involving 1996 patients who were admitted with heart failure between December 2016 and June 2019. Outcome was a composite endpoint of all-cause death or rehospitalization at 3 months.

Results

The incidence of the composite endpoint was 26.8% (535/1,996); it was 32.2% (213/662), 25.0% (165/661), and 23.3% (157/673) by chloride tertiles (from the lowest to the highest), respectively. The serum chloride at admission was independently and inversely associated with the composite endpoint risk (hazard ratio: 0.967; 95% confidence interval: 0.939 to 0.996; p = 0.026) in contrast to sodium, which was no longer significant (p > 0.05) after multivariable adjustment. Pearson correlation between serum chloride and sodium was 0.747 (p < 0.001). However, an increased AUC was not observed by adding sodium to model composed of age, sex, NYHA class, diabetes, log BNP and chloride (0.620 vs. 0.612, p = 0.132). Subgroup analysis showed the presence or absence of hyponatremia did not affect the association between chloride and composite endpoint risk.

Conclusions

Low serum chloride at admission was associated with poor outcomes in Chinese hospitalized patients with heart failure. These findings warrant future studies for tackling the potential pathophysiological mechanisms and correction methods of hypochloremia in heart failure.

Clinical relevance of serum electrolytes in dogs and cats with acute heart failure: A retrospective study

Background

Hypochloremia is a strong negative prognostic factor in humans with congestive heart failure (CHF), but the implications of electrolyte abnormalities in small animals with acute CHF are unclear.

Objectives

To document electrolyte abnormalities present upon admission of small animals with acute CHF, and to assess the relationship between electrolyte concentrations and diuretic dose, duration of hospitalization and survival time.

Animals

Forty‐six dogs and 34 cats with first onset of acute CHF.

Methods

Retrospective study. The associations between electrolyte concentrations and diuretic doses were evaluated with Spearman rank correlation coefficients. Relationship with duration of hospitalization and survival were assessed by simple linear regression and Cox proportional hazard regression, respectively.

Results

The most commonly encountered electrolyte anomaly was hypochloremia observed in 24% (9/46 dogs and 10/34 cats) of cases. In dogs only, a significant negative correlation was identified between serum chloride concentrations at admission (median 113 mmol/L [97‐125]) and furosemide doses both at discharge (median 5.2 mg/kg/day [1.72‐9.57]; r = −0.59; P < .001) and at end‐stage heart failure (median 4.7 mg/kg/day [2.02‐7.28]; r = −0.62; P = .005). No significant hazard ratios were found for duration of hospitalization nor survival time for any of the electrolyte concentrations.

Conclusions and Clinical Importance

The observed association between serum chloride concentrations and diuretic doses suggests that hypochloremia could serve as a marker of disease severity and therapeutic response in dogs with acute CHF.