Genetic tailoring of pharmacotherapy in heart failure: optimize the old, while we wait for something new

BACKGROUND

The combination of angiotensin-converting enzyme (ACE) inhibitors and beta-adrenergic receptor blockers remains the essential component of heart failure (HF) pharmacotherapy. However, individual patient responses to these pharmacotherapies vary widely. The variability in response cannot be explained entirely by clinical characteristics, and genetic variation may play a role. The purpose of this review is to examine our current state of understanding of beta-blocker and ACE inhibitor pharmacogenetics in HF.

METHODS AND RESULTS

Beta-blocker and ACE inhibitor pharmacogenetic studies performed in patients with HF were identified from the Pubmed database from 1966 to July 2011. Thirty beta-blocker and 10 ACE inhibitor pharmacogenetic studies in patients with HF were identified. The ACE deletion variant was associated with greater survival benefit from ACE inhibitors and beta-blockers compared with the ACE insertion. Ser49 in the beta-1 adrenergic receptor, the insertion in the alpha-2C adrenergic receptor, and Gln41 in G-protein-coupled receptor kinase 5 are associated with greater survival benefit from beta-blockers, compared with Gly49, the deletion, and Leu41, respectively. However, many of these associations have not been validated.

CONCLUSIONS

The HF pharmacogenetic literature is still in its very early stages, but there are promising candidate genetic variants that may identify which HF patients are most likely to benefit from beta-blockers and ACE inhibitors and patients that may require additional therapies.

Hyponatremia's Impact on Patients and Health Systems

Purpose

To define hyponatremia, discuss its incidence and epidemiology, and summarize the frequency and prognostic implications of hyponatremia in selected clinical conditions.

Summary

Hyponatremia is the most common electrolyte abnormality encountered in clinical practice. Hyponatremia is commonly defined as a serum sodium concentration of <136 mEq/L. There are 3 different types of hyponatremia: hypovolemia, euvolemia, and hypervolemia. Epidemiologic studies reveal that hyponatremia is a common problem in hospitalized patients whether it is present at admission or is hospital acquired. The disorder increases the risk of admission to the intensive care unit, hospital length of stay, and morbidity and mortality. Hyponatremia appears to be a marker for severe underlying disease with a poor prognosis. Congestive heart failure, pneumonia, cirrhosis, and neurologic disease are among the serious clinical conditions known to be associated with hyponatremia. Chronic hyponatremia presents its own set of challenges; even in mild disease that is often asymptomatic, patients are at heightened risk for falls, gait disturbances, attention deficits, and fracture.

Conclusion

Hyponatremia is the most common electrolyte disorder encountered in clinical practice and is associated with significant morbidity and mortality, especially at lower serum sodium concentrations. The disorder has a substantial impact on hospital length of stay with a direct impact on health care costs. Further, as this discussion illustrates, hyponatremia represents a significant clinical burden in all forms – mild, moderate, and severe – with subsequent clinical consequences.

Modulation of novel cardiorenal and inflammatory biomarkers by intravenous nitroglycerin and nesiritide in acute decompensated heart failure: an exploratory study

BACKGROUND

Modulation of novel cardiorenal and inflammatory markers may provide insight into the disease process and outcomes of patients with acute decompensated heart failure.

METHODS AND RESULTS

In this open-labeled, prospective, randomized study, 89 patients received either nesiritide (NES) or nitroglycerin (NTG) infusion by standard protocol. The serum or plasma concentrations of cystatin-C and inflammatory markers (high-sensitivity C-reactive protein, tumor necrosis factor-α, transforming growth factor-β1, and interleukin-6) were measured in 66 patients with acute decompensated heart failure at baseline and during drug infusion. Mean baseline values for demographics were not significantly different between NTG and NES groups; however, baseline inflammatory markers were elevated on admission. In NES compared with NTG groups, lower cystatin-C (1449 versus 2739 ng/mL, P<0.05) and IL-6 (25 versus 50 pg/mL, P<0.05) were observed. There were no significant differences in concentrations of high-sensitivity C-reactive protein, tumor necrosis factor-α, and transforming growth factor-β1 between groups over time.

CONCLUSIONS

The differential modulation effects of cystatin-C and interleukin-6 but not other inflammatory markers, in response to NES compared with NTG therapy, may provide important implications for vasodilator therapy. Further studies are warranted to confirm these findings.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00842023.

Clinical predictors of in-hospital mortality in acutely decompensated heart failure-piecing together the outcome puzzle

The substantial public health impact of hospitalization for acute decompensated heart failure, from an economic and clinical perspective, has generated substantial interest in understanding predictors of risk in this syndrome. Utilization of classification and regression tree (CART) analysis on the Acute Decompensated Heart Failure National Registry (ADHERE) dataset has provided important risk stratification from readily available clinical variables. Increasingly, high-risk patients were identified by combination of blood urea nitrogen level of 43 mg/dL, serum creatinine level of 2.75 mg/dL, and systolic blood pressure less than 115 mm Hg, which were all independent predictors of high risk for in-hospital mortality. On the basis of these 3 variables, acutely decompensated heart failure patients can be readily stratified into groups at low, intermediate, and high risk for in-hospital mortality, with mortality risks ranging from 2.1% to 21.9%. Although risk stratification alone cannot improve outcomes, identification of patients at high and low risk may improve resource utilization and better focus the intensity of care according to outcome.

Implementing critical pathways and a multidisciplinary team approach to cardiovascular disease management

According to several medical registries, there is a need to improve the care of post-myocardial infarction (MI) patients, especially those with left ventricular dysfunction (LVD) and heart failure. This can potentially be achieved by implementing disease management programs, which include critical pathways, patient education, and multidisciplinary hospital teams. Currently, algorithms for critical pathways, including discharge processes, are lacking for post-MI LVD patients. Such schemes can increase the use of evidence-based medicines proved to reduce mortality. Educational programs are aimed at increasing patients' awareness of their condition, promoting medication compliance, and encouraging the adoption of healthy behaviors; such programs have been shown to be effective in improving outcomes of post-MI LVD patients. Reductions in all-cause hospitalizations and medical costs as well as improved survival rates have been observed when a multidisciplinary team (a nurse, a pharmacist, and a hospitalist) is engaged in patient care. In addition, the use of the "pay for performance" method, which can be advantageous for patients, physicians, and hospitals, may potentially improve the care of post-MI patients with LVD.

Relation of sex to morbidity and mortality in patients with heart failure and reduced or preserved left ventricular ejection fraction

BACKGROUND

Previous studies indicate a survival advantage for women over men with chronic heart failure associated with reduced or preserved ejection fraction. Whether women with chronic heart failure are at less risk for hospitalization for worsening heart failure has not been well investigated.

METHODS

Using data from the DIG trial, the relationship between sex and adverse outcomes, especially the risk of hospitalization for various causes, was evaluated in patients with reduced or preserved left ventricular ejection fraction.

RESULTS

Survival was worse for men than women with either reduced (HR 1.48, 95% CI 1.33-1.65, P < .001) or preserved ejection fraction (HR 1.60, 95% CI 1.20-2.13, P = .001), with P =.406 for sex interaction. In contrast, the risk of hospitalization for heart failure was greater in men than women when ejection fraction was reduced (HR 1.19, 95% CI 1.07-1.33, P = .001) but not preserved (HR 0.90, 95% CI 0.67-1.22, P = .494), with P = .003 for sex interaction. The relative risk of hospitalization for worsening failure between reduced and preserved ejection fraction was greater in men than women (HR 5.97, 95% CI 1.40-25.56, P = .001 in men vs HR 2.65, 95% CI 0.68-10.31, P = .159 in women).

CONCLUSION

A survival advantage for women was seen in heart failure with reduced or preserved ejection fraction. In contrast, women appeared to be at lower risk for hospitalization for heart failure only when left ventricular systolic dysfunction was present.

Synergistic polymorphisms of beta1 and alpha2C-adrenergic receptors and the influence on left ventricular ejection fraction response to beta-blocker therapy in heart failure

OBJECTIVES

The Arg389Gly polymorphism (Arg389Gly) in the beta1-adrenergic receptor gene (ADRB1) has been associated with improvement in left-ventricular remodeling with beta-blocker treatment. One study of risk for heart failure suggested a synergistic effect of ADRB1 Arg389Gly with the insertion/deletion polymorphism in the alpha2C-adrenergic receptor gene (ADRA2C). We tested whether the ADRA2C insertion/deletion polymorphism was associated with beta-blocker response in heart failure, either alone or in combination with the ADRB1Arg389Gly polymorphism.

METHODS

Fifty-four beta-blocker naive heart failure patients underwent echocardiography before and after 5-6 months of metoprolol CR/XL therapy. Multivariant linear regression modeling was performed to assess the impact of genotypes and other variables on changes in left-ventricular function in response to metoprolol therapy.

RESULTS

Deletion carriers had a significantly greater negative chronotropic response. Predictors of the end of study ejection fraction were baseline ejection fraction, deletion carrier status and Arg389Arg genotype. Patients with Arg389Arg/Del-carrier status showed the greatest ejection fraction increase with metoprolol CR/XL. Adjusting for baseline ejection fraction, final S-metoprolol plasma concentration and race, final ejection fraction in patients with this genotype combination was significantly higher than all other genotype combination groups.

CONCLUSION

ADRB1 and ADRA2C polymorphisms synergistically influence the ejection fraction response to beta-blocker therapy of heart failure patients.

Current Guidelines for Treatment of Heart Failure: 2006 Update

Several pivotal clinical trials have generated new knowledge regarding drug therapy for heart failure. Thus, the Heart Failure Society of America (HFSA) and the American College of Cardiology-American Heart Association (ACC-AHA) guidelines were updated in 2006 and 2005, respectively. We review the evidence from these trials and summarize the changes to the HFSA and ACC-AHA guidelines. Based on data from these studies, the new guidelines include broader, stronger recommendations for beta-blocker therapy, and strong recommendations for angiotensin II receptor blockers. The aldosterone antagonists, spironolactone and eplerenone, are also included in the guidelines. Pharmacists should have a basic level of familiarity with the new guidelines on heart failure and the evidence from recent clinical studies. They should be able to relate how this information contributes to the evolving understanding of treatment strategies for heart failure.

Relationship of Serum Digoxin Concentration to Mortality and Morbidity in Women in the Digitalis Investigation Group Trial

OBJECTIVES

The purpose of this study was to investigate the relationship of serum digoxin concentration (SDC) and outcomes in women with heart failure (HF).

BACKGROUND

Controversy continues concerning the clinical utility of digoxin in women with HF.

METHODS

Our analysis was retrospective with data from the Digitalis Investigation Group (DIG) trial. The principal study analysis reviewed 4,944 patients with HF due to systolic dysfunction who survived for at least 4 weeks (all 3,366 patients randomized to placebo and the 1,578 of 3,372 patients randomized to digoxin who had serum concentration measured 6 to 30 h [inclusive] after the last dose of study drug at 4 weeks).

RESULTS

Continuous multivariable analysis demonstrated a significant linear relationship between SDC and mortality in women (p = 0.008) and men (p = 0.002, p = 0.766 for gender interaction). Averaging hazard ratios (HRs) across serum concentrations from 0.5 to 0.9 ng/ml in women produced a HR for death of 0.8 (95% confidence interval [CI] 0.62 to 1.13, p = 0.245) and for death or hospital stay for worsening HF of 0.73 (95% CI 0.58 to 0.93, p = 0.011). In contrast, SDCs from 1.2 to 2.0 ng/ml were associated with a HR for death for women of 1.33 (95% CI 1.001 to 1.76, p = 0.049).

CONCLUSIONS

Retrospective analysis of data from the DIG trial indicates a beneficial effect of digoxin on morbidity and no excess mortality in women at serum concentrations from 0.5 to 0.9 ng/ml, whereas serum concentrations > or =1.2 ng/ml seem harmful.

??1-Adrenergic receptor polymorphisms and left ventricular remodeling changes in response to ??-blocker therapy

OBJECTIVE

Large variability exists in the improvement in left ventricular (LV) function from beta-blocker treatment. We hypothesized that polymorphisms at codon 389 (Arg389Gly) and 49 (Ser49Gly) in the beta1-adrenergic receptor (AR) gene were associated with LV reverse remodeling changes in response to beta-blocker therapy among heart failure patients.

METHODS

We prospectively enrolled 61 beta-blocker naive patients with systolic heart failure. Patients underwent baseline echocardiography followed by metoprolol CR/XL. The dose was doubled on a biweekly basis up to 200 mg/day or attainment of maximum tolerated dose. Echocardiography was repeated after the patient received the target or highest tolerated dose for 3 months.

RESULTS

Among patients with the Arg389Arg genotype, ejection fraction (EF) increased from 23+/-5 to 29+/-10 (P=0.008). Gly389 carriers did not demonstrate any significant change in EF (22+/-9 to 23+/-11; P=0.45). There was a significant between-group difference in EF by genotype (P=0.04). The Arg389Arg genotype was also associated with significantly greater reductions in LV end-diastolic and end-systolic diameters compared to Gly389 carriers. Patients with the Gly49 variant also had a significantly greater reduction in LV end-diastolic diameter compared to Ser49 homozygotes. Multiple regression analysis modeling revealed that the codon 389 polymorphism was a significant predictor of an improvement in EF and both codon 49 and 389 polymorphisms were significant predictors of final LV end-diastolic diameter.

CONCLUSIONS

Heart failure patients with the Arg389Arg genotype and Gly49 carriers had greater improvements in LV remodeling from beta-blocker treatment.