Reassessment of dobutamine, dopamine, and milrinone in the management of acute heart failure syndromes

Acute heart failure syndromes and coronary perfusion

Acute heart failure syndromes (AHFS), with a high post-discharge mortality and rehospitalization rate, represent a significant public health burden. The treatment of patients hospitalized with AHFS often includes the use of vasoactive medications such as inotropes and vasodilators. Although such agents are frequently used, their safety and efficacy remain controversial. A significant number of patients with heart failure have underlying coronary artery disease and may be at greater risk from hemodynamic alterations that can diminish coronary perfusion. In AHFS, the relationship among vasoactive medications, coronary perfusion, and potential myocardial injury needs further investigation. Newer techniques now available to evaluate coronary perfusion should provide guidance for the evaluation of existing and future vasoactive therapies for AHFS.

New therapies in acute decompensated heart failure

PURPOSE OF REVIEW

Hospitalization and mortality rates associated with heart failure are persistently high. This is due partly to aging of the population but mostly to delayed progress in the pharmacological treatment of decompensated heart failure. We will review the current recommendations and most recent advancement in the pharmacological treatment of acute decompensated heart failure while providing a systematic approach to the management of this prevalent condition.

RECENT FINDINGS

Loop diuretics, nitrates and inotropes such as dobutamine and milrinone are the current mainstay of acute heart failure management although their associated morbidity and possible mortality have raised serious concerns. Recent vasoactive agents such as Nesiritide, Tolvaptan and more recently the inotropic agent Levosimedan could offer improved hemodynamics and congestive relief to patients in acute pulmonary edema.

SUMMARY

Despite the promising results of these agents, further clinical trials are required prior to their international approval as first-line therapy. Although we can be optimistic that these vasoactive drugs might have favorable clinical outcomes and improve the intricate management of decompensated heart failure, their associated mortality benefit remains unclear and controversial.

Overview of emerging pharmacologic agents for acute heart failure syndromes

BACKGROUND

Several therapies commonly used for the treatment of acute heart failure syndromes (AHFS) present some well-known limitations and have been associated with an early increase in the risk of death. There is, therefore, an unmet need for new pharmacologic agents for the early management of AHFS that may improve both short- and long-term outcomes.

AIM

To review the recent evidence on emerging pharmacologic therapies in AHFS.

METHODS

A systematic search of peer-reviewed publications was performed on MEDLINE, EMBASE and Clinical Trials.gov from January 1990 to August 2007. 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.

RESULTS

Cumulative data from large studies and randomised trials suggest that therapies with innovative mechanisms of action may safely and effectively reduce pulmonary congestion or improve cardiac performance in AHFS patients.

CONCLUSION

Some investigational agents for the management of AHFS are able to improve haemodynamics and/or clinical status. In spite of these promising findings, no new agent has demonstrated a clear benefit in terms of long-term clinical outcomes compared to placebo or conventional therapies.

Right ventricular dysfunction

PURPOSE OF REVIEW

Until recently the right ventricle's role in myocardial dynamics has not been fully appreciated. This article provides an overview of the pathophysiology, imaging and management of right ventricular dysfunction.

RECENT FINDINGS

That levosimendan may promote right ventricular function opens new avenues for treatment. In addition there are existing therapies such as phosphodiesterase inhibitors and nitric oxide, which offer yet further modalities to improve outcome in right ventricular failure. How these drugs are used, in combination or alone, in conjunction with ventilatory and cardiovascular strategies has not been evaluated in multicentred randomized controlled trials.

SUMMARY

Acute right ventricular dysfunction is relatively common. There is a lack of convincing evidence in favour of any single treatment modality. Imaging methods now permit a more accurate evaluation of the right ventricle and its function. Combining treatments may offer significant advantages and the imaging and monitoring available allows real-time assessment of the response to intervention. This article illustrates how incomplete our knowledge of this condition and its management within the critical care setting is and reinforces previous calls for suitably designed trials to evaluate and develop guidelines for existing strategies and therapeutic agents.

[Vasopressin as a rescue vasopressor agent. Treatment of selected cardiogenic shock states]

Vasodilatory shock is the most common form of shock in the critically ill patient. As a consequence of overwhelming and prolonged mediator production, vasodilatory shock can be the common final pathway of primary non-vasodilatory shock (e.g. cardiogenic or hypovolemic shock). A supplementary infusion of arginine vasopressin (AVP) showed beneficial effects on hemodynamics and potentially on the outcome in patients with vasodilatory shock due to sepsis or after major surgery. In this case series, successful administration of AVP in three surgical patients with primary cardiogenic shock forms is reported. The hemodynamic effects of AVP were comparable to those AVP-induced alterations described in septic shock and seem to be predominantly mediated by potent vasoconstriction and the facilitated reduction of higher, potentially toxic catecholamine doses. Thus, an AVP-induced decrease in heart rate and pulmonary arterial pressures may be particularly beneficial in patients with impaired cardiac function.

The costs of treating acute heart failure: an economic analysis of the SURVIVE trial

OBJECTIVE

To estimate the incremental cost per life year gained with levosimendan relative to dobutamine in treatment of acute heart failure based on the Survival of Patients with Acute Heart Failure in Need of Intravenous Inotropic Support (SURVIVE) trial.

METHODS

SURVIVE enrolled 1,327 patients (levosimendan 664, dobutamine 663) from nine nations with 180-day survival from date of randomisation as the primary endpoint. Hospital resource utilisation was determined via clinical case reports. Unit costs were derived from hospital payment schedules for France, Germany and the UK, and represent a third-party payer perspective. Cost-effectiveness analysis was performed for a subset of the SURVIVE patient population selected in accordance with current levosimendan labeling.

RESULTS

Mortality in the levosimendan group was 26 versus 28% for dobutamine (hazard ratio 0.91, 95% confidence interval 0.74-1.13, p=0.40). Initial hospitalisation length of stay was identical (levosimendan 14.4, dobutamine 14.5, p=0.98). Slightly lower rates of readmission were observed for levosimendan relative to dobutamine at 31 (p=0.13) and 180 days (p=0.23). Mean costs excluding study drug were equivalent for the index admission (levosimendan euro5,060, dobutamine euro4,952; p=0.91) and complete episode (levosimendan euro5,396, dobutamine euro5,275; p=0.93).

CONCLUSION

At an acquisition cost of euro600 per vial, there is at least 50% likelihood that levosimendan is cost effective relative to dobutamine if willingness to pay is equal to or greater than euro15,000 per life year gained.

Comparison of two dose regimens of arginine vasopressin in advanced vasodilatory shock

OBJECTIVE

To evaluate the effects of two arginine vasopressin (AVP) dose regimens (0.033 vs. 0.067 IU/min) on treatment efficacy, hemodynamic response, prevalence of adverse events, and changes in laboratory variables.

DESIGN

Retrospective, controlled study.

PATIENTS

A total of 78 patients with vasodilatory shock (mean norepinephrine dosage, 1.07 microg.kg-1.min-1; 95% confidence interval, 0.82-1.56 microg.kg-1.min-1).

INTERVENTIONS

Supplementary infusion of AVP at 0.033 (n = 39) and 0.067 IU/min (n = 39).

MEASUREMENTS AND MAIN RESULTS

Cardiocirculatory, laboratory, and clinical variables were evaluated and compared between groups before and at 0.5, 1, 4, 12, 24, 48, and 72 hrs after initiation of AVP. Treatment efficacy was assessed by the increase in mean arterial blood pressure and the extent of norepinephrine reduction during the first 24 hrs of AVP therapy. Standard tests and a mixed-effects model were used for statistical analysis. Although the relative increase in mean arterial pressure was comparable between groups (0.033 vs. 0.067 IU/min: 16.8 +/- 18.4 vs. 21.4 +/- 14.9 mm Hg, p = .24), norepinephrine could be reduced significantly more often in patients receiving 0.067 IU/min. AVP at 0.067 IU/min resulted in a higher mean arterial pressure (p < .001), lower central venous pressure (p = .001), lower mean pulmonary arterial pressure (p = .04), and lower norepinephrine requirements (p < .001) during the 72-hr observation period. Increases in liver enzymes occurred more often in patients treated with 0.033 IU/min (71.8% vs. 28.2%, p < .001). The prevalence of a decrease in cardiac index (69.2% vs. 53.8%, p = .24), decrease in platelet count (94.8% vs. 84.6%, p = .26), and increase in total bilirubin (48.7% vs. 71.8%, p = .06) was not significantly different between groups. Bilirubin levels (3.1 +/- 3.4 vs. 5.2 +/- 5.5 mg/dL, p = .04) and base deficit (-7.2 +/- 4.3 vs. -3.9 +/- 5.9 mmol/L, p = .005) were lower and arterial lactate concentrations higher (76 +/- 67 vs. 46 +/- 38 mg/dL, p < .001) in patients receiving 0.033 IU/min.

CONCLUSIONS

AVP dosages of 0.067 IU/min seem to be more effective to reverse cardiovascular failure in vasodilatory shock requiring high norepinephrine dosages than 0.033 IU/min.

Management of acute decompensated heart failure

Acute decompensated heart failure is the most common cause for hospitalization among patients over 65 years of age. It may result from new onset of ventricular dysfunction or, more typically, exacerbation of chronic heart failure symptoms. In-hospital mortality remains high for both systolic and diastolic forms of the disease. Therapy is largely empirical as few randomized, controlled trials have focused on this population and consensus practice guidelines are just beginning to be formulated. Treatment should be focused upon correction of volume overload, identifying potential precipitating causes, and optimizing vasodilator and beta-adrenergic blocker therapy. The majority of patients (>90%) will improve without the use of positive inotropic agents, which should be reserved for patients with refractory hypotension, cardiogenic shock, end-organ dysfunction, or failure to respond to conventional oral and/or intravenous diuretics and vasodilators. The role of aldosterone antagonists, biventricular pacing, and novel pharmacological agents including vasopressin antagonists, endothelin blockers, and calcium-sensitizing agents is also reviewed.

Genetic engineering and therapy for inherited and acquired cardiomyopathies

The cardiac myofilaments consist of a highly ordered assembly of proteins that collectively generate force in a calcium-dependent manner. Defects in myofilament function and its regulation have been implicated in various forms of acquired and inherited human heart disease. For example, during cardiac ischemia, cardiac myocyte contractile performance is dramatically downregulated due in part to a reduced sensitivity of the myofilaments to calcium under acidic pH conditions. Over the last several years, the thin filament regulatory protein, troponin I, has been identified as an important mediator of this response. Mutations in troponin I and other sarcomere genes are also linked to several distinct inherited cardiomyopathic phenotypes, including hypertrophic, dilated, and restrictive cardiomyopathies. With the cardiac sarcomere emerging as a central player for such a diverse array of human heart diseases, genetic-based strategies that target the myofilament will likely have broad therapeutic potential. The development of safe vector systems for efficient gene delivery will be a critical hurdle to overcome before these types of therapies can be successfully applied. Nonetheless, studies focusing on the principles of acute genetic engineering of the sarcomere hold value as they lay the essential foundation on which to build potential gene-based therapies for heart disease.

The hemodynamic effects of insulin following overdosage with levobupivacaine or racemic bupivacaine in dogs

Although levobupivacaine (LBUP) is less cardiotoxic than racemic bupivacaine (RBUP), the resuscitation from the LBUP-induced cardiovascular collapse (CVC) has not been easy as expected. Following the recent reports that proposed the resuscitative action of insulin for the RBUP-induced CVC, a controlled trial was performed to assess the feasibility of insulin for the LBUP-induced CVC. Fourteen dogs were randomly allocated into two groups: the RBUP and LBUP groups. Each group received continuous intravenous infusions of RBUP or LBUP until the mean arterial pressure (MAP) reached 40 mmHg. Then, an intravenous bolus of insulin (2 U/kg) was administered. Both groups were successfully resuscitated. At CVC, a decrease of cardiac output and an increase of systemic vascular resistance were observed but to a lesser degree in the LBUP group (p<0.05). After insulin injection, the MAP further declined to under 40 mmHg for several minutes, which was more protracted in the LBUP group (p<0.05). The CVCs induced by LBUP or RBUP in anesthetized dogs could be successfully resuscitated by insulin. Compared with RBUP, however, the less degree of vasoconstriction by LBUP and the innate vasodilatory property of insulin yielded a delayed increment of MAP during the immediate resuscitation period in the LBUP-induced CVC.

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.

Istaroxime, a stimulator of sarcoplasmic reticulum calcium adenosine triphosphatase isoform 2a activity, as a novel therapeutic approach to heart failure

Interventions involving calcium cycling may represent a promising approach to heart failure (HF) therapy because calcium handling is known to be deranged in human and experimental HF. Istaroxime is a sodium-potassium adenosine triphosphatase (ATPase) inhibitor with the unique property of increasing sarcoplasmic reticulum calcium ATPase (SERCA) isoform 2a (SERCA2a) activity. Because this was demonstrated in normal experimental models, we investigated whether istaroxime is able to improve global cardiac function and stimulate SERCA in failing hearts. In guinea pigs with 3-month aortic banding (AoB), echocardiographic results showed that istaroxime intravenous infusion (0.11 mg/kg per min) significantly increased both indices of contraction and relaxation (fractional shortening, +18+/-3.7%; aortic flow rate, +19+/-2.9%; peak myocardial systolic velocity, +36+/-7%; circumferential fiber shortening, +24+/-4.1%; peak atrial flow velocity, +69+/-8.6%; isovolumic relaxation time, +19+/-6.9%; and peak myocardial early diastolic velocity, +42+/-12%). In left ventricular sarcoplasmic reticulum microsomes from AoB animals, 100 nmol/L istaroxime normalized the depressed (-32%) SERCA2a maximum velocity and increased SERCA activity (+17%). In muscle strips from hearts from patients undergoing cardiac transplantation, istaroxime (0.1-1.0 micromol/L) increased (in a concentration-dependent manner) developed tension, the maximum and minimum first derivative of tension, and absolute velocity of contraction, while stimulating SERCA activity in sarcoplasmic reticulum microsomes at physiologic free calcium concentrations. In conclusion, istaroxime is presently the only available compound that stimulates SERCA2a activity and produces a luso-inotropic effect in HF.

Targeting SERCA2a as an innovative approach to the therapy of congestive heart failure

CHF prevalence is continuously increasing worldwide and maintains one of the poorest prognoses of any major disease. Abundant evidence points to derangement of Ca(2+) cycling as the primary biochemical mark of the failing myocyte. Istaroxime is a novel compound with a dual mechanism of action: inhibition of Na(+), K(+)-ATPase and stimulation of SERCA2a. The increase in cytoplasmic Ca(2+) due to Na(+), K(+)-ATPase inhibition together with greater sarcoplasmic reticulum reloading result in both increased inotropy and lusitropy. This effect is seen in normal and failing in vitro and in vivo models. Istaroxime improvement of the contraction-relaxation cycle constitutes a novel therapeutic approach to the treatment of heart failure.

Chronic inotropic therapy in end-stage heart failure

BACKGROUND

Interventions in advanced heart failure that provide symptom relief and decrease hospital readmission are important. Chronic intravenous inotropic therapy represents a pharmacologic approach that has been advocated for palliative treatment. However, little is known about associated mortality and cost. Therefore, we sought to describe the impact of chronic infusions on resource use and survival.

METHODS

Data were reviewed for a 17-state Medicare region from 1995 to 2002. We obtained hospital and outpatient expenditures accrued up to 180 days before and after the initiation of chronic infusions. Health care use was defined by dollars reimbursed for drug and hospitalizations per beneficiary. Average accumulated cost curves were generated for dollars reimbursed for drug and for hospitalizations by days at risk.

RESULTS

The mean age of the cohort (n = 331) was 69.1 +/- 11.3 years. Mortality exceeded 40% at 6 months. Reductions in hospital days were observed at all time points. The amounts reimbursed at 30 and 60 days before and after initiation of inotrope favor drug therapy; however, at six months, the amounts reimbursed were greater due to the cost of milrinone.

CONCLUSIONS

Chronic intravenous inotrope use was associated with a high mortality. The cost for milrinone was significant, but there was a decrease in expenditures for subsequent hospitalizations. In the absence of appropriately designed clinical trials, the data suggest that the decision to use inotropes, the choice of inotrope, and the duration of treatment should reflect the impact on resource use.

Emerging therapies for the management of decompensated heart failure: from bench to bedside

While pharmaceutical innovation has been highly successful in reducing mortality in chronic heart failure, this has not been matched by similar success in decompensated heart failure syndromes. Despite outstanding issues over definitions and end points, we argue in this paper that an unprecedented wealth of pharmacologic innovation may soon transform the management of these challenging patients. Agents that target contractility, such as cardiac myosin activators and novel adenosine triphosphate-dependent transmembrane sodium-potassium pump inhibitors, provide inotropic support without arrhythmogenic increases in cytosolic calcium or side effects of more traditional agents. Adenosine receptor blockade may improve glomerular filtration and diuresis by exerting a direct beneficial effect on glomerular blood flow while vasopressin antagonists promote free water excretion without compromising renal function and may simultaneously inhibit myocardial remodeling. Urodilatin, the renally synthesized isoform of atrial natriuretic peptide, may improve pulmonary congestion via vasodilation and enhanced diuresis. Finally, metabolic modulators such as perhexiline may optimize myocardial energy utilization by shifting adenosine triphosphate production from free fatty acids to glucose, a unique and conceptually appealing approach to the management of heart failure. These advances allow optimism not only for the advancement of our understanding and management of decompensated heart failure syndromes but for the translational research effort in heart failure biology in general.

Beta-blocker use in decompensated heart failure

Despite the current advances in treatment, acute decompensated heart failure accounts for more than 1 million hospital admissions annually. Many of the patients hospitalized are already receiving long-term treatment with beta-blockers. For patients who receive full dose beta-blocker therapy and suffer acute decompensated heart failure, clinicians face two key questions: what to do, if anything, with the dosage of beta-blocker and what is the best way to integrate inotropic and beta-blocker therapies for patients who require inotropes. This article discusses these issues and reviews the available literature. Because these topics have received little systematic evaluation, we also present our clinical approaches to these problems.

Use of nesiritide before and after publications suggesting drug-related risks in patients with acute decompensated heart failure

CONTEXT

The rate of adoption of new therapies for cardiovascular diseases following the publication of favorable clinical trial results has been studied; however, less is known about the rates of de-adoption of a drug when negative studies are published.

OBJECTIVE

To evaluate the use of nesiritide before and after March and April 2005 publications in 2 high-impact journals that suggested an increased risk of renal failure and mortality with intravenous nesiritide for acute decompensated heart failure.

DESIGN, SETTING, AND PATIENTS

Analysis of a large prospective hospital database, developed for quality and utilization benchmarking, of 491 acute care US hospitals at which 385,627 inpatient admissions occurred with a primary International Classification of Diseases, Ninth Revision (ICD-9) code for heart failure between January and August 2001 (prior to nesiritide release) and January 2004 to December 2005 (before and after publication periods). In addition, any patient admitted who received nesiritide in the absence of a primary or secondary heart failure code was evaluated for potential off-label use of the drug.

MAIN OUTCOME MEASURE

Use of nesiritide and other intravenous vasoactive therapy among patients admitted with heart failure.

RESULTS

Nesiritide use decreased from a peak of 16.6% (2351 of 14,167 admissions) in March 2005 to 5.6% (611 of 10,822 admissions) in December 2005 (P<.001). Among those patients treated with nesiritide, the mean duration of treatment changed minimally, from 2.3 to 2.1 days. Although the use of inotropes also decreased during the period under study, the changes were more modest; furthermore, of those patients who were prescribed intravenous vasoactive therapy, a higher percentage were prescribed inotropes after publication (3272 [21.5%] of 15 193 patients from January-April 2005 vs 5750 [29.6%] of 19 445 patients from May-December 2005, P<.001). The use of nesiritide, in the absence of an ICD-9 heart failure code, was small.

CONCLUSIONS

Rapid de-adoption of nesiritide occurred following 2 publications suggesting risk with the drug. Further analyses are required to evaluate the consequences of these changes on patient outcomes and to anticipate how publications of adverse findings can influence practice.

Drug therapy recommendations from the 2005 ACC/AHA guidelines for treatment of chronic heart failure

OBJECTIVE

To review and discuss key aspects of the drug therapy recommendations in the American College of Cardiology (ACC)/American Heart Association (AHA) 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure (HF) in the Adult.

DATA SOURCES

Data were obtained from the ACC/AHA 2005 Guideline Update for Chronic HF. English-language clinical trials, observational studies, and pertinent review articles evaluating the pharmacotherapy of chronic HF were identified, based on MEDLINE searches through January 2006.

STUDY SELECTION

Articles presenting information that impacts the evidence base for recommendations regarding the use of various drug therapies in patients with chronic HF were evaluated.

DATA SYNTHESIS

The ACC/AHA 2005 Guideline Update for HF provides revised, evidence-based recommendations for the treatment of chronic HF. The new guidelines are based on a staging system that recognizes both the development and progression of HF. Recommendations are provided for 2 stages of patients (A and B) who do not yet have clinical HF but are clearly at risk and 2 stages (C and D) that include patients with symptomatic HF. The guidelines continue to emphasize the important role of neurohormonal blockade with angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, beta-adrenergic blockers, and aldosterone antagonists. Based on recent trials, updated recommendations address the roles of combination therapy and the selective addition of hydralazine and isosorbide dinitrate. Along with specific drug recommendations, information on the practical use of various drugs is provided. Although the guidelines primarily focus on HF due to systolic dysfunction, general recommendations are also provided for patients with preserved systolic function.

CONCLUSIONS

The ACC/AHA 2005 Guideline Update provides evidence-based recommendations for healthcare professionals involved in the care of adults with chronic HF. Recent clinical trial findings have further clarified the evolving role of neurohormonal-blocking drugs in the prevention and treatment of HF.

Diuretic resistance in heart failure

The use of diuretics for the treatment of heart failure (HF) is ubiquitous in any basic HF medical regimen. Although initially these drugs clearly show benefit by relieving symptomatic episodes of decompensated HF, long-term use of these drugs can lead to a "diuretic-resistant" state and is associated with an increased risk of morbidity and mortality. A number of factors may be responsible for this, including dietary noncompliance, inadequate diuretic dosing or methods of administration, and concomitant use of certain medications. Diuretics themselves may set in motion an iatrogenic cardiorenal syndrome leading to worsening renal function and diuretic resistance. The methods for overcoming this resistance are varied and require a focused approach with emphasis on relieving the congestive symptoms related to HF while attempting to preserve renal function and minimize any untoward systemic effects.

Randomized clinical trials with levosimendan

There are important unmet needs in the treatment of acute heart failure syndromes (AHFS). The unique dual mechanism of action of levosimendan suggests that this new agent may help fill some of these unmet needs. A review of randomized, controlled clinical trials with levosimendan demonstrated that it is well tolerated, and its use results in significantly reduced pulmonary capillary wedge pressure (PCWP) and increased cardiac output. Effects of levosimendan on PCWP and cardiac output are more pronounced than those observed with dobutamine. Levosimendan treatment is also associated with significantly improved clinical symptoms. Moreover, data from 3 trials indicate that levosimendan treatment was associated with improved 6-month survival compared with dobutamine treatment or placebo. Emerging data suggest that levosimendan is beneficial for patients with acute myocardial ischemia. Thus, early clinical indicators suggest that levosimendan may help prevent myocardial injury during hospitalization for AHFS and may be well suited for first-line therapy for AHFS.

The Pilot Randomized Study of Nesiritide Versus Dobutamine in Heart Failure (PRESERVD-HF)

Acute heart failure syndromes (AHFS) are related to several diseases affecting not only the heart but also the kidneys and blood vessels. Emerging evidence indicates that myocardial injury may also play a role in the pathophysiology of AHFS, as suggested by increased levels of markers of injury, such as cardiac troponin (cTn). Although cTn is a known prognostic marker, the release of cTn during hospitalization has not been evaluated prospectively with serial measures. We prospectively evaluated patterns of cTn release by conducting serial measures of cTnI and cTnT in patients hospitalized for AHFS. This study enrolled 51 patients with AHFS who were admitted with worsening heart failure (HF) and a history of coronary artery disease (CAD) in whom an acute coronary event was not suspected. Levels of cTnI and cTnT were measured at 8, 32, 56, and 80 hours after study entry. At baseline, 73.9% of patients had detectable cTnI, and 43.5% had detectable cTnT levels. The median concentrations of cTnI and cTnT were unchanged from 0 to 32 hours, increased from 32 to 56 hours, then either plateaued (cTnT) or decreased to baseline (cTnI). Of the 26 patients who had no detectable cTn levels at baseline, 2 (7.7%) developed detectable cTnT and 5 (41.7%) developed detectable cTnI release during hospitalization. Detectable levels of cTn at baseline were related to short-term clinical events. In this study of patients with CAD in whom an acute coronary event was not suspected, most had detectable levels of cTn present at admission, and some patients developed cTn release during hospitalization. Because cTn release may be a marker for myocardial injury, this study raises the possibility that injury occurred in most patients admitted with AHFS. Therefore, the goal of therapy for AHFS should be not only to improve symptoms and hemodynamics but also to salvage myocardium. Accordingly, therapies for AHFS that are aimed at improving hemodynamics may affect long-term prognosis by either injuring or salvaging myocardium.

Pathophysiologic targets in the early phase of acute heart failure syndromes

An episode of acute heart failure syndromes (AHFS) can be defined as a rapid or gradual onset of signs and symptoms of heart failure (HF) in hospital admission and can arise from a variety of pathophysiologic mechanisms. This article reviews our current understanding of the pathophysiology of AHFS in order to identify potential therapeutic targets. Most patients with AHFS present with either normal systolic blood pressure or elevated blood pressure. Patients who present with elevated systolic blood pressure usually have pulmonary congestion and a relatively preserved left ventricular ejection fraction (LVEF), and have symptoms that typically develop abruptly, these patients often are elderly women. Patients with normal systolic blood pressure presenting with systemic congestion and reduced LVEF are usually younger, with a history of chronic HF, and have symptoms that develop gradually over days or weeks. Accordingly, most episodes of AHFS can be classified as either "vascular" failure or "cardiac" failure. In addition to the abnormal hemodynamics (increase in pulmonary capillary wedge pressure and/or decrease in cardiac output) that characterize patients with AHFS, myocardial injury--which may be related to a decrease in coronary perfusion and/or further activation of neurohormones and renal dysfunction (ie, the cardiorenal syndrome)--probably contributes to short-term and post-discharge cardiac events. Patients with AHFS also have significant cardiac and non-cardiac underlying conditions that contribute to the pathogenesis of AHFS, including coronary artery disease (ischemia, hibernating myocardium, and endothelial dysfunction), hypertension, atrial fibrillation, and type 2 diabetes mellitus. The goals of therapy for AHFS should be not only to improve symptoms and hemodynamics, but also to preserve or improve renal function and prevent myocardial damage.