Acute Decompensated Heart Failure
Hospital admissions for acute decompensated heart failure (ADHF) have increased precipitously during the past few decades and are projected to continue to increase in the future. To optimize patient outcomes and reduce the costs associated with this disorder, evidenced-based pharmacotherapy is essential. Continuous infusions of loop diuretic therapy rather than bolus dosing may enhance efficacy and reduce the extent of diuretic resistance. Nesiritide is a pharmacologically novel preload and afterload reducer but based on clinical trial evidence should be reserved for those unable to take or with resistance to intravenous nitrate therapy. Catecholamine- and phosphodiesterase-based inotropic therapies are efficacious, but the increased risk of arrhythmogenesis and the potential for negative survival effects limit their use. The experimental agent levosimendan is a positive inotropic agent but does not increase myocyte calcium concentrations as do catecholamines or phosphodiesterase inhibitors. Clinical trial evidence demonstrates a positive survival benefit for levosimendan versus dobutamine.

During the past 20 years, the number of hospital discharges related to heart failure has risen by 155%, which is primarily attributed to the rising geriatric population and improved treatments for acute myocardial infarction. Acute decompensated heart failure (ADHF) is the single most expensive hospital admission diagnosis according to the Center for Medicare and Medicaid Administration, with more than $3.6 billon spent in 1998 alone. Overall, 47% of patients admitted for ADHF are readmitted within 90 days. Nonaggressive medical care during the index ADHF hospital-ization, suboptimal treatment before readmission, and patient noncompliance contribute strongly to the high readmission rate. Fifty percent of patients with classic ADHF symptoms before admission receive no alteration in their treatment at initial consultation with their health care provider. Among readmissions for ADHF caused by noncompliance, 77% are related to excessive daily consumption of sodium or water, whereas 9.5% are related to drug therapy nonadherence. Patient noncompliance is related to an inadequate understanding of heart failure and its treatment and can be predicted by the presence or absence of nonmodifiable risk factors for ADHF, including younger age, depression, Medicare or Medicaid as the primary insurer, and low income level.

There are several other etiologic mechanisms that contribute to the development of decompen-sation in the patient with stable heart failure. Pharmacologic agents that expand plasma volume (i.e., glucocorticoids, nonsteroidal antiinflammatory agents, thiazolidinediones, and vasodilators [e.g., hydralazine, minoxidil, or prazosin]) or exhibit negative inotropic effects (i.e., propafenone, disopyramide, and nondihydro-pyridine calcium channel antagonists) can increase the risk of decompensation. Develop-ment of resistance to angiotensin-converting enzyme (ACE) inhibitors over time (also known as ACE escape) may also precipitate development of decompensation. Recent studies have identified several nonpharmacologic precipitants to decompensation, including cardiac arrhythmias, infection, anemia, winter weather, rheumatologic diseases, and uncontrolled thyroid dysfunction.

Given the burden of ADHF hospital admissions and readmissions on patients and the health care system, proactive management of patient com-pliance and aggressive control of precipitating factors associated with decompensation are essential. Control of these factors should reduce the occurrence of avoidable episodes of decompensation. However, episodes of decompensation attributed to disease progression require optimal management to ensure prolonged survival and an improved quality of life for the patient with heart failure. Therefore, a systematic overview of the pathophysiology, symptomatology, and pharmaco-therapeutic management of ADHF was performed by using a MEDLINE database search from 1966 to early 2003. Selected references from the articles identified from the database search were also incorporated where applicable.