Placebo-controlled, randomized, double-blind study of intravenous enalaprilat efficacy and safety in acute cardiogenic pulmonary edema

Vasodilators for Acute Heart Failure - A Systematic Review with Meta-Analysis

BACKGROUND

Acute heart failure is a public health concern. This study systematically reviewed randomized clinical trials (RCTs) to evaluate vasodilators in acute heart failure.

METHODS

The search was conducted across the databases of Medline, Embase, Latin American and the Caribbean Literature on Health Sciences, Web of Science, and the Cochrane Central Register of Controlled Trials. Inclusion criteria consisted of RCTs that compared vasodilators versus standard care, placebo, or cointerventions. The primary outcome was all-cause mortality; secondary outcomes were serious adverse events (SAEs), tracheal intubation, and length of hospital stay. Risk of bias was assessed in all trials.

RESULTS

The study included 46 RCTs that enrolled 28,374 patients with acute heart failure. Vasodilators did not reduce the risk of all-cause mortality (risk ratio, 0.95; 95% confidence interval [CI], 0.87 to 1.04; I2=9.51%; P=0.26). No evidence of a difference was seen in the risk of SAEs (risk ratio, 1.01; 95% CI, 0.97 to 1.05; I2=0.94%) or length of hospital stay (mean difference, -0.10; 95% CI, -0.28 to 0.08; I2=69.84%). Vasodilator use was associated with a lower risk of tracheal intubation (risk ratio, 0.54; 95% CI, 0.30 to 0.99; I2=51.96%) compared with no receipt of vasodilators.

CONCLUSIONS

In this systematic review with meta-analysis of patients with acute heart failure, vasodilators did not reduce all-cause mortality.

Management of hypertensive crisis: British and Irish Hypertension Society Position document

Patients with hypertensive emergencies, malignant hypertension and acute severe hypertension are managed heterogeneously in clinical practice. Initiating anti-hypertensive therapy and setting BP goal in acute settings requires important considerations which differ slightly across various diagnoses and clinical contexts. This position paper by British and Irish Hypertension Society, aims to provide clinicians a framework for diagnosing, evaluating, and managing patients with hypertensive crisis, based on the critical appraisal of available evidence and expert opinion.

Blood Pressure Reduction in Hypertensive Acute Heart Failure

PURPOSE OF REVIEW

To review the key clinical and research questions regarding blood pressure (BP) reduction with vasodilators in the early management of hypertensive acute heart failure (H-AHF).

RECENT FINDINGS

Despite numerous AHF vasodilator clinical trials in the past two decades, virtually none has studied a population where vasoconstriction is the predominant physiology, and with the agents and doses most commonly used in contemporary practice. AHF patients are remarkably heterogenous by vascular tone, and this heterogeneity is not always discernible through BP or clinical exam. Emerging data suggest that diastolic BP may be a stronger correlate of vascular tone in AHF than systolic BP, despite the latter historically serving as a key inclusion criterion for vasodilator clinical trials. Existing data are limited. A clinical trial that evaluates vasodilators in a manner of use consistent with contemporary practice, specifically within the subpopulation of patients with true H-AHF, is greatly needed. Until then, observational data supports long-standing vasodilators such as nitroglycerin, administered by IV bolus, and with goal reduction of SBP ≤25% as a safe first-line approach for patients with severe H-AHF presentations.

Safety and Prognostic Impact of Early Treatment with Angiotensin-Converting Enzyme Inhibitors or Angiotensin Receptor Blockers in Patients with Acute Heart Failure

BACKGROUND

Although angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) have been recommended for patients with heart failure, their clinical and prognostic impact in the very acute phase of acute heart failure (AHF) is unclear, mainly because data on their safety and efficacy are lacking.

METHODS

This study was a post hoc analysis of the REALITY-AHF trial. Patients with AHF who did not take an ACEI or ARB at admission were enrolled. Patients who received these medications within 48 h of admission were categorized as the ACEI/ARB group, and all other patients were categorized as the no ACEI/ARB group. The primary endpoint was a composite of all-cause death and heart failure readmission within 1 year of admission.

RESULTS

Of the 1682 patients in the REALITY-AHF cohort, 900 were enrolled in this study, and 288 (32%) were included in the ACEI/ARB group. After propensity score matching, 152 pairs were evaluated, and no significant difference was found for in-hospital mortality, worsening renal function, or length of hospital stay. The ACEI/ARB group had significantly higher event-free survival (hazard ratio 0.51; 95% confidence interval 0.32-0.82; p = 0.006).

CONCLUSIONS

Early initiation of ACEIs/ARBs within 48 h of admission for hospitalized patients with AHF was not associated with adverse events and correlated with improved outcomes at 1 year from admission.

Biased ligand of the angiotensin II type 1 receptor in patients with acute heart failure: a randomized, double-blind, placebo-controlled, phase IIB, dose ranging trial (BLAST-AHF)

Aims

Currently, no acute heart failure (AHF) therapy definitively improves outcomes. Reducing morbidity and mortality from acute heart failure (AHF) remains an unmet need. TRV027 is a novel 'biased' ligand of the angiotensin II type 1 receptor (AT1R), selectively antagonizing the negative effects of angiotensin II, while preserving the potential pro-contractility effects of AT1R stimulation. BLAST-AHF was designed to determine the safety, efficacy, and optimal dose of TRV027 to advance into future studies.

Methods and results

BLAST-AHF was a multi-centre, international, randomized, double-blind, placebo-controlled, parallel group, phase IIb dose-ranging study, enrolling patients with AHF into 4 groups: placebo, 1, 5, or 25 mg/h of TRV027. Treatment was by IV infusion for 48-96 h. The primary composite endpoint was comprised of the following: (i) time from baseline to death through day 30, (ii) time from baseline to heart failure re-hospitalization through day 30, (iii) the first assessment time point following worsening heart failure through day 5, (iv) change in dyspnea visual analogue scale (VAS) score calculated as the area under the curve (AUC) representing the change from baseline over time from baseline through day 5, and (v) length of initial hospital stay (in days) from baseline. Analyses were by modified intention-to-treat. Overall, 621 patients were enrolled. After 254 patients, a pre-specified interim analysis resulted in several protocol changes, including a lower blood pressure inclusion criterion as well as a new allocation scheme of 2:1:2:1, overweighting both placebo, and the 5 mg/h dose. TRV027 did not confer any benefit over placebo at any dose with regards to the primary composite endpoint or any of the individual components. There were no significant safety issues with TRV027.

Conclusion

In this phase IIb dose-ranging AHF study, TRV027 did not improve clinical status through 30-day follow-up compared with placebo.

Vasodilators in acute heart failure - evidence based on new studies

Acute heart failure (AHF) contributes largely to the worldwide burden of heart failure (HF) and is associated with high mortality, poor prognosis and high rehospitalization rate. The pharmacologic therapy of AHF includes diuretics and vasodilators, which are a keystone when fluid overload and congestion are present. However, vasodilators are mainly focused on controlling symptoms, and drugs that also improve long-term mortality and morbidity seem to be in high demand. In this review, we summarize the existing evidence on mortality benefits of IV vasodilators in AHF. There is lack of evidence on the mortality benefits of IV vasodilators in AHF, as well as well-designed and large-scale trials for some of them. The existing trials on nitrates have conflicting results and are insufficient to establish definitive conclusions. Other vasodilators, such as enalaprilat, clevidipine, carperitide, and ularitide, have been evaluated only in a few trials assessing mortality. Levosimendan, nesititide and carperitide are approved by some regulatory agencies; however, data regarding mortality are also conflicting and large-scale post-marketing studies would be important. Serelaxin is a recent therapy with a novel mechanism of action and seemed to be promising; although serelaxin was safe and well tolerated in earlier trials, the results of a larger phase III trial failed to meet the primary endpoints of reduction in cardiovascular death at day 180 and reduction of worsening heart failure at day 5. The absence of definitive mortality benefits and high-quality and large-scale data not allow firm conclusions to be drawn about the role of IV vasodilators in AHF. Well-designed studies are needed to clarify the role of these drugs in the long-term outcome of AHF, as well as new therapies entering the clinical investigation.

Optimizing Hypertensive Acute Heart Failure Management with Afterload Reduction

PURPOSE OF REVIEW

In spite of advances in our understanding of acute heart failure (AHF) and its different phenotypic expressions, AHF management is still centered on volume removal with intravenous diuretics. This narrative review describes the pathophysiology underlying hypertensive AHF and appraises therapies targeting these mechanisms.

RECENT FINDINGS

Vascular redistribution rather than volume overload may be the primary determinant of elevated cardiac filling pressures and subsequent pulmonary congestion in patients with hypertensive AHF; in these patients, vasodilators should be the predominant treatment. Additional therapy with diuretics in hypertensive AHF should be relegated to the treatment of overt volume overload or persistent congestion in spite of optimized hemodynamics. Intravenous nitroglycerin at high doses can rapidly achieve pulmonary decongestion and reduce downstream critical care needs in these patients. The therapeutic role for synthetic peptides with vasodilator properties has yet to be defined. Evidence supporting both old and new vasodilator therapies is limited by a paucity of well-designed studies and failure to demonstrate improvement in long-term outcomes. Targeted study of this phenotype of AHF is needed before vasodilator therapies become incorporated into treatment guidelines.

Intravenous enalaprilat for treatment of acute hypertensive heart failure in the emergency department

Background

Afterload reduction with bolus enalaprilat is used by some for management of acute hypertensive heart failure (HF) but existing data on the safety and effectiveness of this practice are limited. The purpose of this study was to evaluate the clinical effects of bolus enalaprilat when administered to patients with acute hypertensive heart failure.

Findings

We performed an IRB-approved retrospective cohort study of patients who presented to the emergency department of a large urban academic hospital. Patients were identified by pharmacy record and included if they received enalaprilat intravenous (IV) bolus in the setting of acute hypertensive HF. A total of 103 patients were included. Patients were hypertensive on presentation (systolic blood pressure [SBP] = 195.2 [SD ± 32.3] mmHg) with significantly elevated mean NT-proBNP levels (3797.8 [SD ± 6523.2] pg/ml). The mean dose of enalaprilat was 1.3 [SD ± 0.7] mg, with most patients (76.7%) receiving a single 1.25 mg bolus. By 3 h post­enalaprilat, SBP had decreased substantially (−30.5 mmHg) with only 2 patients (1.9%) developing hypotension. Renal function was unaffected, with no significant change in serum creatinine by 72 h. In the 30 days post-admission, patients spent an average of 23 [SD ± 7.5] days alive and out of hospital.

Conclusions

In this retrospective cohort of acute hypertensive HF patients, bolus IV enalaprilat resulted in a substantial reduction in systolic BP without adverse effect.

Clinical and Research Considerations for Patients With Hypertensive Acute Heart Failure: A Consensus Statement from the Society for Academic Emergency Medicine and the Heart Failure Society of America Acute Heart Failure Working Group

Management approaches for patients in the emergency department (ED) who present with acute heart failure (AHF) have largely focused on intravenous diuretics. Yet, the primary pathophysiologic derangement underlying AHF in many patients is not solely volume overload. Patients with hypertensive AHF (H-AHF) represent a clinical phenotype with distinct pathophysiologic mechanisms that result in elevated ventricular filling pressures. To optimize treatment response and minimize adverse events in this subgroup, we propose that clinical management be tailored to a conceptual model of disease that is based on these mechanisms. This consensus statement reviews the relevant pathophysiology, clinical characteristics, approach to therapy, and considerations for clinical trials in ED patients with H-AHF.

Drug Therapy for Acute Heart Failure

Acute heart failure is globally one of most frequent reasons for hospitalization and still represents a challenge for the choice of the best treatment to improve patient outcome. According to current international guidelines, as soon as patients with acute heart failure arrive at the emergency department, the common therapeutic approach aims to improve their signs and symptoms, correct volume overload, and ameliorate cardiac hemodynamics by increasing vital organ perfusion. Recommended treatment for the early management of acute heart failure is characterized by the use of intravenous diuretics, oxygen, and vasodilators. Although these measures ameliorate the patient's symptoms, they do not favorably impact on short- and long-term mortality. Consequently, there is a pressing need for novel agents in acute heart failure treatment with the result that research in this field is increasing worldwide.

Lack of evidence for intravenous vasodilators in ED patients with acute heart failure: a systematic review

There are nearly 700,000 annual US emergency department (ED) visits for acute heart failure (AHF). Although blood pressure is elevated on most of these visits, acute therapy remains focused on preload and not afterload reduction. Data from recent prospective studies suggest that patients with AHF with concomitant acute hypertension benefit from intravenous (IV) vasodilators. To better understand the use of vasodilators for such patients, we conducted a systematic review of (1) currently available intravenous vasodilators for ED patients with AHF, or (2) intravenous vasodilators that are not yet available, but have completed phase III clinical trials in AHF, and may be available for ED use in the future. We used multiterm search queries to retrieve research involving nitroglycerin, nitroprusside, enalaprilat, hydralazine, relaxin, and nesiritide. A total of 2001 unique citations were identified from 3 databases: PubMed, EMBASE, and CINAHL. Of these, 1966 were excluded on the basis of established review criteria, leaving 35 published articles for inclusion. Our primary finding was that intravenous nitrovasodilators, when used in the treatment of AHF in ED and ED-like settings, do improve short-term symptoms and appear safe to administer. There are no data suggesting that they impact mortality. Other commonly used vasodilators such as hydralazine and enalaprilat have very little published data about their safety and efficacy. Of note, few studies enrolled patients early in their course of treatment. Thus, to assess the specific impact of vasodilator therapy on both short- and long-term outcomes, future research efforts should focus on patient recruitment in the ED setting.

Heart failure therapeutics on the basis of a biased ligand of the angiotensin-2 type 1 receptor. Rationale and design of the BLAST-AHF study (Biased Ligand of the Angiotensin Receptor Study in Acute Heart Failure)

The BLAST-AHF (Biased Ligand of the Angiotensin Receptor Study in Acute Heart Failure) study is designed to test the efficacy and safety of TRV027, a novel biased ligand of the angiotensin-2 type 1 receptor, in patients with acute heart failure (AHF). AHF remains a major public health problem, and no currently-available therapies have been shown to favorably affect outcomes. TRV027 is a novel biased ligand of the angiotensin-2 type 1 receptor that antagonizes angiotensin-stimulated G-protein activation while stimulating β-arrestin. In animal models, these effects reduce afterload while increasing cardiac performance and maintaining stroke volume. In initial human studies, TRV027 appears to be hemodynamically active primarily in patients with activation of the renin-angiotensin-aldosterone system, a potentially attractive profile for an AHF therapeutic. BLAST-AHF is an international prospective, randomized, phase IIb, dose-ranging study that will randomize up to 500 AHF patients with systolic blood pressure ≥120 mm Hg and ≤200 mm Hg within 24 h of initial presentation to 1 of 3 doses of intravenous TRV027 (1, 5, or 25 mg/h) or matching placebo (1:1:1:1) for at least 48 h and up to 96 h. The primary endpoint is a composite of 5 clinical endpoints (dyspnea, worsening heart failure, length of hospital stay, 30-day rehospitalization, and 30-day mortality) combined using an average z-score. Secondary endpoints will include the assessment of dyspnea and change in amino-terminal pro-B-type natriuretic peptide. The BLAST-AHF study will assess the efficacy and safety of a novel biased ligand of the angiotensin-2 type 1 receptor in AHF.

From acute decompensated to chronic heart failure

An acute decompensation of heart failure resulting in hospital admission represents a critical juncture in the natural history of the disease, as evidenced by poor mortality and readmission outcomes after hospital discharge. For this reason, a number of new short-term vasoactive therapies have been or are being tested in clinical trials. Furthermore, in response to unacceptable readmission rates, there has been intense interest in improving the transition from hospital discharge to the outpatient arena. Between these 2 areas of focus exists an often overlooked internal transition from acute vasoactive therapies to oral chronic heart failure medications. This transition from acute presentation to the rest of the hospital stay forms the basis of this review.

The role of the emergency department in the patient with acute heart failure

The diagnosis and management of the patient with acute decompensated heart failure (ADHF) presents a unique challenge to the emergency medicine (EM) physician. ADHF is one of the most common cardiac emergencies managed in the emergency department (ED). ED presentations for ADHF will grow as survival rates after myocardial infarction continue to increase and thus, the incidence and prevalence of heart failure (HF) increases. There are very little data to aid EM physicians when trying to identify low-risk patients who are safe for ED discharge and observation units are not yet universally utilized. This results in 80% of patients with ADHF getting admitted to the hospital. The aim of this review is to evaluate current strategies for diagnosis, treatment, and disposition of the ADHF patient in the ED while highlighting new approaches for treatment and disposition, and areas in need of additional research.

Initial management of patients with acute heart failure

Pressure exists to manage patients with acute decompensated heart failure (ADHF) efficiently in the acute-care environment. Although most patients present with worsening of chronic heart failure, some may present with undifferentiated dyspnea and new-onset heart failure. Others have significant comorbidities that complicate both the diagnosis and treatment. The treatment of patients with ADHF is prioritized based on vital signs and presenting phenotype. The risk stratification of patients is the subject of ongoing evaluation. The disposition of patients to areas other than a monitored inpatient bed, such as an emergency department-based observation unit, may prove effective.

Acute Heart Failure Treatment

Dyspnea is the predominant symptom for patients with acute heart failure and initial treatment is largely directed towards the alleviation of this. Contrary to conventional belief, not all patients present with fluid overload and the approach to management is rapidly evolving from a solitary focus on diuresis to one that more accurately reflects the complex interplay of underlying cardiac dysfunction and acute precipitant. Effective treatment thus requires an understanding of divergent patient profiles and an appreciation of various therapeutic options for targeted patient stabilization. The key principle within this paradigm is directed management that aims to diminish the work of breathing through situation appropriate ventillatory support, volume reduction and hemodynamic improvement. With such an approach, clinicians can more efficiently address respiratory discomfort while reducing the likelihood of avoidable harm.

Acute lung failure

Lung failure is the most common organ failure seen in the intensive care unit. The pathogenesis of acute respiratory failure (ARF) can be classified as (1) neuromuscular in origin, (2) secondary to acute and chronic obstructive airway diseases, (3) alveolar processes such as cardiogenic and noncardiogenic pulmonary edema and pneumonia, and (4) vascular diseases such as acute or chronic pulmonary embolism. This article reviews the more common causes of ARF from each group, including the pathological mechanisms and the principles of critical care management, focusing on the supportive, specific, and adjunctive therapies for each condition.

Effect of early treatment with anti-hypertensive drugs on short and long-term mortality in patients with an acute cardiovascular event

BACKGROUND

Acute cardiovascular events represent a therapeutic challenge. Blood pressure lowering drugs are commonly used and recommended in the early phase of these settings. This review analyses randomized controlled trial (RCT) evidence for this approach.

OBJECTIVES

To determine the effect of immediate and short-term administration of anti-hypertensive drugs on all-cause mortality, total non-fatal serious adverse events (SAE) and blood pressure, in patients with an acute cardiovascular event, regardless of blood pressure at the time of enrollment.

SEARCH STRATEGY

MEDLINE, EMBASE, and Cochrane clinical trial register from Jan 1966 to February 2009 were searched. Reference lists of articles were also browsed. In case of missing information from retrieved articles, authors were contacted.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing anti-hypertensive drug with placebo or no treatment administered to patients within 24 hours of the onset of an acute cardiovascular event.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed risk of bias. Fixed effects model with 95% confidence intervals (CI) were used. Sensitivity analyses were also conducted.

MAIN RESULTS

Sixty-five RCTs (N=166,206) were included, evaluating four classes of anti-hypertensive drugs: ACE inhibitors (12 trials), beta-blockers (20), calcium channel blockers (18) and nitrates (18). Acute stroke was studied in 6 trials (all involving CCBs). Acute myocardial infarction was studied in 59 trials. In the latter setting immediate nitrate treatment (within 24 hours) reduced all-cause mortality during the first 2 days (RR 0.81, 95%CI [0.74,0.89], p<0.0001). No further benefit was observed with nitrate therapy beyond this point. ACE inhibitors did not reduce mortality at 2 days (RR 0.91,95%CI [0.82, 1.00]), but did after 10 days (RR 0.93, 95%CI [0.87,0.98] p=0.01). No other blood pressure lowering drug administered as an immediate treatment or short-term treatment produced a statistical significant mortality reduction at 2, 10 or >/=30 days. There was not enough data studying acute stroke, and there were no RCTs evaluating other acute cardiovascular events.

AUTHORS' CONCLUSIONS

Nitrates reduce mortality (4-8 deaths prevented per 1000) at 2 days when administered within 24 hours of symptom onset of an acute myocardial infarction. No mortality benefit was seen when treatment continued beyond 48 hours. Mortality benefit of immediate treatment with ACE inhibitors post MI at 2 days did not reach statistical significance but the effect was significant at 10 days (2-4 deaths prevented per 1000). There is good evidence for lack of a mortality benefit with immediate or short-term treatment with beta-blockers and calcium channel blockers for acute myocardial infarction.

Early pharmacological treatment of acute heart failure syndromes: A systematic review of clinical trials

CONTEXT

Acute Heart Failure Syndromes (AHFS) is a common admission diagnosis associated with high mortality and hospital readmissions. Given the mixed results of recent clinical trials, the early management of AHFS remains controversial.

OBJECTIVE

To review the recent evidence regarding current and investigational therapies for the early management of AHFS.

DATA SOURCES

A systematic search of peer-reviewed publications was performed on MEDLINE and EMBASE from January 1990 to August 2006. The results of unpublished or ongoing trials were obtained from presentations at national and international meetings and pharmaceutical industry releases. Bibliographies from these references were also reviewed, as were additional articles identified by content experts.

STUDY SELECTION AND DATA EXTRACTION

Criteria used for study selection were controlled study design, relevance to clinicians and validity based on venue of publication and power analysis.

DATA SYNTHESIS

Although all current intravenous therapies for the early management of AHFS appear to improve hemodynamics, this may not always translate into short-term clinical benefit.

CONCLUSION

The results of the trials conducted to date in AHFS have generally been disappointing. There is, therefore, an unmet need for new therapeutic approaches for the early management of AHFS that may improve the short-term and long-term outcomes.

Pharmacological interventions for hypertensive emergencies

BACKGROUND

Hypertensive emergencies, marked hypertension associated with acute end-organ damage, are life-threatening conditions. Many anti-hypertensive drugs have been used in these clinical settings. The benefits and harms of such treatment and the best first-line treatment are not known.

OBJECTIVES

To answer the following two questions using randomized controlled trials (RCTs): 1) does anti-hypertensive drug therapy as compared to placebo or no treatment affect mortality and morbidity in patients presenting with a hypertensive emergency? 2) Does one first-line antihypertensive drug class as compared to another antihypertensive drug class affect mortality and morbidity in these patients?

SEARCH STRATEGY

Electronic sources: MEDLINE, EMBASE, Cochrane clinical trial register. In addition, we searched for references in review articles and trials. We attempted to contact trialists. Most recent search August 2007.

SELECTION CRITERIA

All unconfounded, truly randomized trials that compare an antihypertensive drug versus placebo, no treatment, or another antihypertensive drug from a different class in patients presenting with a hypertensive emergency.

DATA COLLECTION AND ANALYSIS

Quality of concealment allocation was scored. Data on randomized patients, total serious adverse events, all-cause mortality, non-fatal cardiovascular events, withdrawals due to adverse events, length of follow-up, blood pressure and heart rate were extracted independently and cross checked.

MAIN RESULTS

Fifteen randomized controlled trials (representing 869 patients) met the inclusion criteria. Two trials included a placebo arm. All studies (except one) were open-label trials. Seven drug classes were evaluated in those trials: nitrates (9 trials), ACE-inhibitors (7), diuretics (3), calcium channel blockers (6), alpha-1 adrenergic antagonists (4), direct vasodilators (2) and dopamine agonists (1). Mortality event data were reported in 7 trials. No meta-analysis was performed for clinical outcomes, due to insufficient data. The pooled effect of 3 different anti-hypertensive drugs in one placebo-controlled trial showed a statistically significant greater reduction in both systolic [WMD -13, 95%CI -19,-7] and diastolic [WMD -8, 95%CI, -12,-3] blood pressure with antihypertensive therapy.

AUTHORS' CONCLUSIONS

There is no RCT evidence demonstrating that anti-hypertensive drugs reduce mortality or morbidity in patients with hypertensive emergencies. Furthermore, there is insufficient RCT evidence to determine which drug or drug class is most effective in reducing mortality and morbidity. There were some minor differences in the degree of blood pressure lowering when one class of antihypertensive drug is compared to another. However, the clinical significance is unknown. RCTs are needed to assess different drug classes to determine initial and longer term mortality and morbidity outcomes.

Review of current and investigational pharmacologic agents for acute heart failure syndromes

Acute heart failure syndromes (AHFS) are a major public health problem and present a therapeutic challenge to clinicians. Commonly used agents in the treatment of AHFS include diuretics, vasodilators (eg, nitroglycerin, nitroprusside, nesiritide), and inotropes (eg, dobutamine, dopamine, milrinone). Patients admitted to hospital with AHFS and low cardiac output state (AHFS/LO) represent a subgroup with very high inhospital and postdischarge mortality rates. Most of these patients require intravenous inotropic therapy. However, the use of current intravenous inotropes has been associated with risk for hypotension, atrial and ventricular arrhythmias, and possibly increased postdischarge mortality, particularly in those with coronary artery disease. Consequently, there is an unmet need for new agents to safely improve cardiac performance (contractility and/or active relaxation) in this patient population. This article reviews a selection of current and investigational agents for the treatment of AHFS, with a main focus on the high-risk patient population with AHFS/LO.

Clinical Features in the Management of Selected Hypertensive Emergencies

A hypertensive emergency is a clinical diagnosis that is appropriate when marked hypertension is associated with acute target-organ damage; in this setting, lowering of blood pressure (BP) is typically begun within hours of diagnosis. For hypertensive urgency with no acute target-organ damage, BP lowering may occur over hours to days. A hypertensive emergency may present with cardiac, renal, neurologic, hemorrhagic, or obstetric manifestations, but prompt recognition of the condition and institution of rapidly acting parenteral therapy to lower BP (typically in an intensive care unit) are widely recommended. For aortic dissection, the systolic BP target is lower than 120 mm Hg, to be achieved during the first 20 minutes using a beta-blocker (typically esmolol) and a vasodilator to reduce both shear stress on the aortic tear and the BP, respectively. Otherwise, sodium nitroprusside is the agent with the lowest acquisition cost and longest record of successful use in hypertensive emergencies; however, it is metabolized to toxic thiocyanate and cyanide. Other attractive agents include fenoldopam mesylate, nicardipine, and labetalol; in pregnant women, magnesium and nifedipine are used commonly. Most authors suggest a reduction in mean arterial pressure of approximately 10% during the first hour and a further 10% to 15% during the next 2 to 4 hours; hypoperfusion can result if the BP is lowered too suddenly or too far (eg, into the range of <140/90 mm Hg). Oral antihypertensive therapy can usually be instituted after 6 to 12 hours of parenteral therapy, and the patient moved out of the intensive care unit, when consideration should be given to screening for secondary causes of hypertension. Long-term follow-up to ensure adequate control of hypertension is necessary to prevent further target-organ damage and recurrence of another hypertensive emergency.

Acute Congestive Heart Failure in the Emergency Department

Acute heart failure and cardiogenic pulmonary edema is a common cause of respiratory distress among patients presenting to the emergency department. The emergency department is frequently the primary entry point into the health care system for these patients and is the site of initial stabilization, evaluation, and management of the patient.Emergency physicians, alongside cardiologists, play a critical role as these patients are treated in the emergency department and transferred to the cardiac ICU. The approach to the critically ill patient who has heart failure should be multidisciplinary and involve the emergency physician and the cardiologist who will care for the patient.

Modern Management of Cardiogenic Pulmonary Edema

Cardiogenic pulmonary edema (CPE) is a life-threatening condition that is frequently encountered in standard emergency medicine practice. Traditionally, diagnosis was based on physical assessment and chest radiography and treatment focused on the use of morphine sulfate and diuretics. Numerous advances in diagnosis and treatment have been made, however. Serum testing for B-type natriuretic peptide (BNP) has improved the accuracy of diagnoses in these patients. Treatment should focus on fluid redistribution with aggressive preload and afterload reduction rather than simply on diuresis. Some specific medications and noninvasive positive pressure ventilation have been shown to be safe and rapidly effective in improving patients' symptoms and improve outcomes.

Beneficial hemodynamic and renal effects of intravenous enalaprilat following coronary artery bypass surgery complicated by left ventricular dysfunction

OBJECTIVE

Angiotensin-converting enzyme inhibitors are an effective therapy for all stages of heart failure due to reduced systolic left ventricular function. Because sufficient data on intravenous angiotensin-converting enzyme inhibitors following coronary artery bypass surgery complicated by postoperative left ventricular dysfunction are unavailable, the efficacy and safety of intravenously administered enalaprilat were evaluated.

DESIGN

A placebo-controlled, randomized, double-blind protocol.

SETTING

Postoperative intensive care unit at the German Heart Institute Berlin.

PATIENTS

Forty patients with a left ventricular ejection fraction <35% following coronary artery bypass surgery on the second postoperative day or after weaning from intra-aortic balloon counterpulsation.

INTERVENTIONS

A loading dose of enalaprilat 0.625 mg infused over 1 hr was followed by 5 mg/24 hrs administered continuously for up to 72 hrs.

MEASUREMENTS AND MAIN RESULTS

Systemic and pulmonary hemodynamic variables, blood gases, hormonal variables, renal function, and electrolytes were measured before and repeatedly during therapy. Acute effects were as follows: At 1 hr, enalaprilat increased the cardiac index (p <.001), stroke volume index (p <.001), and right ventricular stroke work index (p <.03) compared with placebo, whereas mean arterial pressure (p <.008) and both systemic (p <.001) and pulmonary (p <.02) vascular resistance decreased. Continuous effects were as follows: Over 72 hrs, enalaprilat decreased diastolic pulmonary artery pressure (p <.019), pulmonary artery occlusion pressure (p <.02), and central venous pressure (p <.02). The cardiac and stroke volume indexes were consistently higher in the enalaprilat group, whereas systemic and pulmonary vascular resistances were lower. The arterial blood-pressure lowering effect was blunted and heart rate remained unchanged. Mixed venous oxygenation (p <.02) was higher and arterial oxygenation was not modified. Finally, enalaprilat increased creatinine clearance (p <.002) and decreased creatinine (p <.02) and urea (p <.03).

CONCLUSIONS

Intravenous enalaprilat safely and effectively improves cardiac and renal function following coronary artery bypass surgery complicated by postoperative left ventricular dysfunction.

Prehospital therapy for acute congestive heart failure: state of the art

Acute congestive heart failure (CHF) is one of the most common syndromes encountered in emergency care settings. Correct diagnosis and treatment for pulmonary edema, the most common acute manifestation of CHF, are of primary importance as misdiagnosis can result in deleterious consequences to patients. The pathogenesis of acute pulmonary edema (APE) is currently believed to arise primarily from the redistribution of intravascular fluid to the lungs secondary to acutely elevated left ventricular (LV) filling pressures. This understanding has provided a basis for the management of acute APE, which entails reduction of LV preload, reduction of LV afterload, ventilatory support, inotropic support as needed, and identification and treatment of other underlying factors contributing to elevated LV filling pressures. The agent most applicable and effective for field treatment is nitroglycerin. Diuretics and morphine should be used with caution, as they carry higher risks, especially in misdiagnosed patients. The role of angiotensin-converting enzyme (ACE) inhibitors has yet to be demonstrated in a prehospital setting. Noninvasive positive pressure ventilation methods are effective adjuncts to current treatment, but their mode of delivery presents technical challenges. The development of novel rapid diagnostic tools, currently in progress, might prove valuable for emergency medical services (EMS) personnel in the future. But for now, EMS personnel must rely on their fundamental skills of history taking and physical examination for accurate diagnosis of CHF.

Effects of enalaprilat on cardiorespiratory, hemodynamic, and hematologic variables in exercising horses

OBJECTIVE

To determine the effects of IV administration of enalaprilat on cardiorespiratory and hematologic variables as well as inhibition of angiotensin converting enzyme (ACE) activity in exercising horses.

ANIMALS

6 adult horses.

PROCEDURE

Horses were trained by running on a treadmill for 5 weeks. Training was continued throughout the study period, and each horse also ran 2 simulated races at 120% of maximum oxygen consumption. Three horses were randomly selected to receive treatment 1 (saline [0.9% NaCl] solution), and the remaining 3 horses received treatment 2 (enalaprilat; 0.5 mg/kg of body weight, IV) before each simulated race. Treatment groups were reversed for the second simulated race. Cardiorespiratory and hematologic data were obtained before, during, and throughout the 1-hour period after each simulated race. Inhibition of ACE activity was determined during and after each race in each horse.

RESULTS

Exercise resulted in significant increases in all hemodynamic variables and respiratory rate. The pH and PO2 of arterial blood decreased during simulated races, whereas PCO2 remained unchanged. Systemic and pulmonary blood pressure measurements and arterial pH, PO2, and Pco2 returned to baseline values by 60 minutes after simulated races. Enalaprilat inhibited ACE activity to < 25% of baseline activity without changing cardiorespiratory or blood gas values, compared with horses administered saline solution.

CONCLUSIONS AND CLINICAL RELEVANCE

Enalaprilat administration almost completely inhibited ACE activity in horses without changing the hemodynamic responses to intense exercise and is unlikely to be of value in preventing exercise-induced pulmonary hemorrhage.

Pharmacokinetic-pharmacodynamic model for perindoprilat regional haemodynamic effects in healthy volunteers and in congestive heart failure patients

AIMS

We compared the relationships between the plasma concentrations (C) of perindoprilat, active metabolite of the angiotensin I-converting enzyme inhibitor (ACEI) perindopril, and the effects (E) induced on plasma converting enzyme activity (PCEA) and brachial vascular resistance (BVR) in healthy volunteers (HV) and in congestive heart failure (CHF) patients after single oral doses of perindopril.

METHODS

Six HV received three doses of perindopril (4, 8, 16 mg) in a placebo-controlled, randomized, double-blind, crossover study whereas 10 CHF patients received one dose (4 mg) in an open study. Each variable was determined before and 6-12 times after drug intake. E (% variations from baseline) were individually related to C (ng ml(-1)) by the Hill model E=Emax x Cgamma/(CE50gamma + Cgamma). When data showed a hysteresis loop, an effect compartment was used.

RESULTS

(means+/-s.d.) In HV, relationships between C and E were direct whereas in CHF patients, they showed hysteresis loops with optimal k(e0) values of 0.13 +/- 0.16 and 0.13 +/- 0.07 h(-1) for PCEA and BVR, respectively. For PCEA, with Emax set to -100%, CE50 = 1.87 +/- 0.60 and 1.36 +/- 1.33 ng ml(-1) (P = 0.34) and gamma = 0.90 +/- 0.13 and 1.11 +/- 0.47 (P = 0.23) in HV and CHF patients, respectively. For BVR, Emax= -41 +/- 14% and -60 +/- 7% (P = 0.02), CE50 = 4.95 +/- 2.62 and 1.38 +/- 0.85 ng ml(-1) (P = 0.02), and gamma = 2.25 +/- 1.54 and 3.06 +/- 1.37 (P = 0.32) in HV and CHF patients, respectively.

CONCLUSIONS

Whereas concentration-effect relationships were similar in HV and CHF patients for PCEA blockade, they strongly differed for regional haemodynamics. This result probably expresses the different involvements, in HV and CHF patients, of angiotensinergic and nonangiotensinergic mechanisms in the haemodynamic effects of ACEIs.

Evaluation and management of acutely decompensated chronic heart failure in the emergency department

A wide range of patients with symptomatic heart failure seek treatment in the emergency department. While there is no single approach to the diversity of patients with acutely decompensated heart failure, certain overarching principles apply. For patients with acute pulmonary edema or cardiogenic shock, the first priority must be rapid stabilization and treatment of reversible problems. For patients with less dramatic presentations, a more systematic search for precipitating factors may be required. Therapy, in general, is directed at reversing dyspnea and/or hypoxemia caused by pulmonary edema, improving systemic perfusion, and reducing myocardial oxygen demand. While morphine and diuretics still have their traditional roles, vasodilators and inotropic agents play an increasingly important part in the modern pharmacologic approach to decompensated heart failure in the emergency department. After evaluation and stabilization in the emergency department, most patients will require hospital admission, although a subset of low-risk patients may be appropriate for discharge to home following a period of observation. Strategies to optimize emergency department care are likely to have an impact upon patient outcomes and upon resource utilization. (c)2001 by CHF, Inc.