Life-threatening hyperkalemia after intravenous labetolol injection for hypertensive emergency in a hemodialysis patient

β-Blocker Use and Risk of Mortality in Heart Failure Patients Initiating Maintenance Dialysis

RATIONAL & OBJECTIVE

Beta-blockers are recommended for patients with heart failure (HF) but their benefit in the dialysis population is uncertain. Beta-blockers are heterogeneous, including with respect to their removal by hemodialysis. We sought to evaluate whether β-blocker use and their dialyzability characteristics were associated with early mortality among patients with chronic kidney disease with HF who transitioned to dialysis.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Adults patients with chronic kidney disease (aged≥18 years) and HF who initiated either hemodialysis or peritoneal dialysis during January 1, 2007, to June 30, 2016, within an integrated health system were included.

EXPOSURES

Patients were considered treated with β-blockers if they had a quantity of drug dispensed covering the dialysis transition date.

OUTCOMES

All-cause mortality within 6 months and 1 year or hospitalization within 6 months after transition to maintenance dialysis.

ANALYTICAL APPROACH

Inverse probability of treatment weights using propensity scores was used to balance covariates between treatment groups. Cox proportional hazard analysis and logistic regression were used to investigate the association between β-blocker use and study outcomes.

RESULTS

3,503 patients were included in the study. There were 2,115 (60.4%) patients using β-blockers at transition. Compared with nonusers, the HR for all-cause mortality within 6 months was 0.79 (95% CI, 0.65-0.94) among users of any β-blocker and 0.68 (95% CI, 0.53-0.88) among users of metoprolol at transition. There were no observed differences in all-cause or cardiovascular-related hospitalization.

LIMITATIONS

The observational nature of our study could not fully account for residual confounding.

CONCLUSIONS

Beta-blockers were associated with a lower rate of mortality among incident hemodialysis patients with HF. Similar associations were not observed for hospitalizations within the first 6 months following transition to dialysis.

Hyperkalemia Induced by the Sequential Administration of Metoprolol and Carvedilol

This report describes the occurrence of asymptomatic hyperkalemia induced by the sequential administration of metoprolol and carvedilol in an 81-year-old man with type II diabetes and stable stage III renal insufficiency. The potassium level rose to 5.6–5.7 mEq/L with metoprolol and normalized when the agent was discontinued. However, the potassium level rose again to 5.6 mEq/L after the administration of carvedilol but the level normalized by halving the dose. The observations of hyperkalemia induced by two different β-blocker drugs in the same patient confirm that this side effect is common to all β-blocker drugs.

Beta blockers in patients with end-stage renal disease-Evidence-based recommendations

For patients who require hemodialysis, beta blockers offer a simultaneous opportunity and challenge in the treatment of cardiovascular disease. Beta blockers are well supported by data from nondialysis populations and directly mitigate the sympathetic overactivity that links chronic kidney disease with cardiovascular sequelae. However, the evidence supporting their use in patients receiving hemodialysis is sparse and the heterogeneity of the beta blocker class makes it difficult to prescribe these medications with confidence. Despite these limitations, both trial and observational data exist that can help guide the use of these medications. In this review, we outline the reasons to consider beta blockers for patients receiving hemodialysis, discuss the barriers to their use, and provide specific evidence-based recommendations for beta blocker use in patients with heart failure, hypertension, ischemic heart disease and arrhythmia.

Possible Metoprolol-Induced Hyperkalemia

Hyperkalemia can be a life-threatening event due to the risk of potentially fatal arrhythmias. Hyperkalemia has been reported in 1.3% (serum potassium greater than 6.0 mEq/mL) to 10% (greater than 5.3 mEq/mL) of patients. Hyperkalemia secondary to beta-adrenergic receptor blockade can occur in 1% to 5% of patients and is more likely to occur in non-cardio-selective beta-blockers versus cardio-selective beta-blockers. This case report describes hyperkalemia in a 72-year-old female with diabetes and underlying chronic renal failure receiving metoprolol. Chronically, potassium balance is maintained by the kidney. In acute situations, such as a larger than normal potassium load, both the kidney and the body's cells react to maintain normal potassium levels. Generally, hyperkalemia occurs secondary to 3 mechanisms: excessive potassium intake, disturbed cellular uptake of potassium, or impaired renal excretion of potassium. Beta-blockers, when used in patients with comorbidities such as renal dysfunction or insulin insufficiency, can potentially cause hyperkalemia. As demonstrated in this case report, hyperkalemia can occur in patients treated with cardio-selective beta-blockers with concurrent risk factors. Health care professionals need to be aware of this potentially life-threatening event to effectively prevent occurrences of beta-blocker-induced hyperkalemia.

Carvedilol-induced hyperkalemia in a patient with chronic kidney disease

A 69-year-old male was admitted to the hospital with a chief complaint of abdominal pain, nausea, and vomiting. He had an extensive past medical history, including diabetes mellitus type 2 and chronic kidney disease stage III. Prior to admission, the patient was taking carvedilol 3.125 mg twice daily with no abnormality in his serum potassium. During hospitalization, his carvedilol was increased to 6.25 mg twice daily. The patient's serum potassium then rose from 4.8 to 6.7 mEq/L, with no improvement following administration of sodium polystyrene sulfonate. Nephrology concluded the carvedilol could be contributing to the hyperkalemia. The dose was decreased back to 3.125 mg twice daily, leading to the potassium normalizing to 4.4 mEq/L. The reported incidence of beta-blocker-induced hyperkalemia is less than 5%. A literature search revealed several cases of beta-blocker-induced hyperkalemia, but to the authors' knowledge, this is the first case describing carvedilol specifically. Utilization of the Naranjo probability scale indicated a possible probability that the carvediol was the cause.

The intuitive case for β-blockers in patients with ESRD

Sudden cardiac death (SCD) is common in dialysis patients accounting for up to 25% of all-cause mortality. Unlike in the general population, occlusive coronary artery disease is implicated in a minority of these deaths. Activation of the sympathetic nervous system is prevalent in the dialysis population and may underlie this high rate of SCD. β-blockers reduce SCD in the general population and, given their mode of action, β-blockers would seem to be an ideal class of agents to prevent SCD in dialysis patients. In this review, we will explore the etiology of SCD in dialysis patients and discuss the evidence supporting the use of β-blockers in patients with ESRD. We will also examine potential impediments to the use β-blocker in the dialysis population and outline directions for future trials in this area.

End-Stage Renal Disease and Sudden Cardiac Death

Patients with end-stage renal disease (ESRD) are at a high risk for sudden cardiac death (SCD). SCD is the most common cause of death in this population and, as in the general population, ventricular arrhythmias seem to be the most common cause of SCD. The increased risk of SCD in ESRD is likely due to factors that are unique to the metabolic derangements associated with this state, as well as the increased prevalence of traditional risk factors. Despite this, the evidence base for the assessment and management of SCD in these patients is limited. This article reviews the current data on underlying risk factors for SCD in patients with ESRD, the role of common medical and device-based therapies for the prevention and treatment of SCD, and the applicability of common methods of risk stratification to patients with ESRD.

Should β-Blockers Be Used to Control Hypertension in People With Chronic Kidney Disease?

Activation of the sympathetic nervous system is common in patients with chronic kidney disease, plays an important role in the genesis of hypertension, the rate of decrease of renal function, and is associated with the increased cardiovascular morbidity and mortality seen in these patients. beta-blockers are potent antihypertensive agents but differ in their hemodynamic effects on renal function. The cardioselective beta-blockers such as atenolol and metoprolol are known to retard the progression of renal diseases, but to a lesser degree compared with blockers of the renin-angiotensin-aldosterone system. However, the newer vasodilating beta-blockers such as carvedilol and nebivolol have different effects on renal hemodynamics and function primarily because of its greater adjunctive alpha1-blocking activity. Carvedilol decreases renal vascular resistance and prevents reductions in the glomerular filtration rate and renal blood flow in patients with hypertension with or without impaired kidney function. In addition, carvedilol may retard progression of albuminuria, and provide cardiorenal protection in chronic kidney disease patients with hypertension, congestive heart failure, and at high risk for sudden cardiac death.

Beta blockers in the management of chronic kidney disease

The sympathetic nervous system modulates renal function through its receptors namely beta1 (cardiac output and renin release), alpha1 (systemic and renovascular constriction), and beta2 renovascular dilation. Sympathetic overactivity is commonly seen in chronic kidney disease (CKD) and is an important contributor to increasing the risk of cardiovascular events as well as increasing renal disease progression. Recent evaluations of drug use in people with CKD shows a remarkably low percentage of patients receiving beta-blockers, especially in more advanced stage CKD when cardiovascular risk is higher. This is in large part due to tolerability of these agents. Moreover, water-soluble beta-blockers such as atenolol and metoprolol are dialyzable and require supplementation to avoid exacerbation of arrhythmias following dialysis. Newer vasodilating beta-blockers have better tolerability and different effects on renal hemodynamics as well as metabolic variables. These effects are related to the relative alpha1-blocking effect of agents such as carvedilol and labetolol, with carvedilol having relatively greater alpha-blocking effects. Few studies evaluate beta-blockers on cardiovascular risk in CKD patients. Studies with carvedilol demonstrate attenuated increases in albuminuria as well as reduction in cardiovascular events in CKD patients with hypertension. This paper reviews the animal and clinical trial data that evaluate beta-blockers in CKD highlighting the vasodilating beta-blockers. It is apparent that greater use of this drug class for blood pressure control would further enhance reduction of risk of heart failure, the most common cause of death in the first year of starting dialysis.

Hyperkalemia: a review

Potassium is the principal intracellular cation, and maintenance of the distribution of potassium between the intracellular and the extracellular compartments relies on several homeostatic mechanisms. When these mechanisms are perturbed, hypokalemia or hyperkalemia may occur. This review covers hyperkalemia, that is, a serum potassium concentration exceeding 5 mmol/L. The review includes a discussion of potassium homeostasis and the etiologies of hyperkalemia and focuses on the prompt recognition and treatment of hyperkalemia. This disorder should be of major concern to clinicians because of its propensity to cause fatal arrhythmias. Hyperkalemia is easily diagnosed, and rapid and effective treatments are readily available. Unfortunately, treatment of this life-threatening condition is often delayed or insufficiently attentive or aggressive.

Drug therapy for hypertension in hemodialysis patients

The majority of end-stage renal disease (ESRD) patients are hypertensive. Drug therapy for hypertension in hemodialysis (HD) patients includes all classes of antihypertensive drugs, with the sole exception of diuretics. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers may decrease morbidity and mortality by reducing the mean arterial pressure (MAP), aortic pulse wave velocity, and aortic systolic pressure augmentation, as well as left ventricular hypertrophy (LVH) and probably reduction of C-reactive protein (CRP) and oxidant stress. Potential risk factors include hyperkalemia, anaphylactoid reaction with AN69 membranes (particularly ACE inhibitors), and aggravation of renal anemia. beta-blockers decrease not only mortality, blood pressure (BP), and ventricular arrhythmias, but also improve left ventricular function in ESRD patients. Nonselective beta-blockers can cause an increase in serum potassium (particularly during fasting or exercise). Lisinopril and atenolol have a predominant renal excretion and therefore a prolonged half life in ESRD patients. Thus thrice-weekly supervised administration of these drugs after HD can enhance BP control. The use of calcium channel blockers is also associated with lower total and cardiovascular-specific mortality in HD patients. Minoxidil is a very potent vasodilator that is generally reserved for dialysis patients with severe hypertension. Hypertensive dialysis patients who are noncompliant with their medications may benefit from transdermal clonidine therapy once a week. The majority of dialysis patients need a combination of several antihypertensive drugs for adequate BP control.

Rates of hyperkalemia after publication of the Randomized Aldactone Evaluation Study

BACKGROUND

The Randomized Aldactone Evaluation Study (RALES) demonstrated that spironolactone significantly improves outcomes in patients with severe heart failure. Use of angiotensin-converting-enzyme (ACE) inhibitors is also indicated in these patients. However, life-threatening hyperkalemia can occur when these drugs are used together.

METHODS

We conducted a population-based time-series analysis to examine trends in the rate of spironolactone prescriptions and the rate of hospitalization for hyperkalemia in ambulatory patients before and after the publication of RALES. We linked prescription-claims data and hospital-admission records for more than 1.3 million adults 66 years of age or older in Ontario, Canada, for the period from 1994 through 2001.

RESULTS

Among patients treated with ACE inhibitors who had recently been hospitalized for heart failure, the spironolactone-prescription rate was 34 per 1000 patients in 1994, and it increased immediately after the publication of RALES, to 149 per 1000 patients by late 2001 (P<0.001). The rate of hospitalization for hyperkalemia rose from 2.4 per 1000 patients in 1994 to 11.0 per 1000 patients in 2001 (P<0.001), and the associated mortality rose from 0.3 per 1000 to 2.0 per 1000 patients (P<0.001). As compared with expected numbers of events, there were 560 (95 percent confidence interval, 285 to 754) additional hyperkalemia-related hospitalizations and 73 (95 percent confidence interval, 27 to 120) additional hospital deaths during 2001 among older patients with heart failure who were treated with ACE inhibitors in Ontario. Publication of RALES was not associated with significant decreases in the rates of readmission for heart failure or death from all causes.

CONCLUSIONS

The publication of RALES was associated with abrupt increases in the rate of prescriptions for spironolactone and in hyperkalemia-associated morbidity and mortality. Closer laboratory monitoring and more judicious use of spironolactone may reduce the occurrence of this complication.

Perioperative management of patients with chronic kidney disease or ESRD

The perioperative management of patients with chronic kidney disease (CKD) or dialysis-dependent end-stage renal disease (ESRD) is complicated by both the underlying renal dysfunction, with associated disturbances of fluid and electrolyte homeostasis and altered drug clearance, and the presence of associated co-morbid conditions, including diabetes mellitus, chronic hypertension and cardiovascular and cerebrovascular disease. The impact of CKD on fluid and electrolyte management, haematological and cardiovascular complications and drug management in the perioperative period are reviewed. Special issues related to the management of haemodialysis and peritoneal dialysis patients in the perioperative period are also reviewed.

Congestive heart failure in patients with chronic kidney disease and on dialysis

CHF is highly prevalent in ESRD and is a leading cause of death in such patients. Hypertension, renal anemia, and comorbid conditions such as coronary artery disease are particularly important risk factors for CHF in ESRD. Dialysis hypotension may be a marker of poor prognosis in such persons. Recent studies suggest that lipid peroxidation and L-carnitine deficiency may contribute to CHF in some patients with ESRD. All forms of renal replacement therapy are capable of ameliorating symptoms of CHF, but their effect on cardiovascular mortality has not been firmly established. Drug therapy, particularly angiotensin-converting enzyme inhibitors and beta-adrenergic receptor blockers, is under-used in patients with ESRD and CHF. Heart/kidney transplantation may be a viable option for some patients with advanced CHF and ESRD.

Labetalol-induced hyperkalemia in renal transplant recipients

BACKGROUND

Labetalol is a commonly used agent for perioperative hypertension in renal transplant recipients. A previous report suggested that labetalol may cause life-threatening hyperkalemia after renal transplantation.

METHODS

We performed a retrospective review of 103 consecutive renal transplants to determine whether labetalol was an independent predictor of hyperkalemia treatment. Thirty-eight patients (36.9%) received labetalol, and 65 patients (63.1%) had no labetalol medication.

RESULTS

Of the 103 patients, 24 (23.3%) required treatment for hyperkalemia. Thirteen (34.2%) of the patients who had labetolol medication and 11 (16.9%) of the patients who did not receive labetalol were treated for hyperkalemia (p = 0.045). Factors considered for a logistic regression model included: the use of labetalol, cold ischemia time, diabetes, and dialysis method; intake of tacrolimus, beta blockers, angiotensin-converting enzyme inhibitors, or other antihypertensives prior to admission; the mannitol dose given intraoperatively, and the 24-hour urine output postoperatively. Intravenous labetalol (odds ratio OR = 4.52, confidence interval CI = 1.33-15.28; p = 0.02), 24- hour urine output (OR = 4.4, CI = 0.97-20.1: p = 0.47), increasing cold ischemia time (OR = 1.09, CI = 1.01-1.17; p = 0.02), and continuous ambulatory peritoneal dialysis (OR = 0.17, CI = 0.29-0.98; p = 0.036) were independent predictors.

CONCLUSION

Labetalol appears to increase the risk of hyperkalemia in patients after renal transplantation.