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Those patients who present in extremis with significant dyspnea and elevated blood pressures may appear to be at the greatest risk for short-term adverse events. However, once acute symptoms are controlled their intermediate (30- to 60-day) risk of adverse events is low when compared with the cohort of patients with normal blood pressure who often present with less severe symptoms.12,18,101 Only a minority of patients manifest low-output signs such as diminished urine production or systemic hypoperfusion.12

Other admission profiles associated with an increased risk of in-hospital mortality include AHFS related to myocardial infarction or ischemia, worsening renal function, or a con- comitant pneumonia.76 Conversely, as many as one-third of patients decompensate because of medication or dietary nonadherence or as a result of poorly controlled hypertension. These individuals have a better short-term prognosis with a reduced risk of early mortality.102 Studies over the past decade have recurrently identified several variables and biomarkers as predictors of adverse events: (1) elevated blood urea nitrogen or creatinine, (2) hyponatremia, (3) ischemic electrocardiogram changes, (4) elevated natriuretic peptide levels, (5) elevated troponins, and (6) low systolic blood pressure.12,65,101,103,104–107 Markers of low-risk AHFS, however, have not been as well delineated. Preliminary work suggests an initial systolic blood pressure over 160 mm Hg and a normal initial cardiac troponin I as markers associated with a decreased risk of adverse events.22 In a large retrospective analysis of a statewide database that utilized recursive partitioning, 17% of ED patients were identified as low risk.108 This somewhat complex model also found systolic blood pressure, serum sodium, and creatinine serving to differentiate between low and high risk. This statistical model was subsequently vali- dated in more than 8300 patients. The model had a negative likelihood ratio of 0.24 (0.18 to 0.32) for identification of 30-day mortality or serious complications.109

Although markers of low-risk presentations have remained somewhat elusive, alternatives to hospitalization have also been investigated. Because the majority of hospitalizations originate from the ED, emergency physicians have consider- able experience stabilizing patients, initiating treatment, and determining disposition in patients with AHFS.64,110 Because most patients with AHFS are admitted for decongestion as a result of worsening chronic HF, a brief period of management in the ED or an ED-based observation unit may be a reasonable alternative to hospitalization in those patients without high-risk features. Such approaches have proved feasible and have been shown to conserve hospital resources.111–114 Although close cardiology follow-up as an outpatient is the cornerstone of success in these brief, ED-driven treatment strategies, even better outcomes may be achieved as the ability to effectively risk-stratify patients improves. Ultimately, delineation of low-risk features and identification of AHFS patients with good intermediate-term prognosis is needed. Further prospec- tive study to identify markers of low-risk AHFS patients is therefore necessary.

Post-ED Course

ment of both newly diagnosed AHFS or recurrent exacerba- tions/complications of chronic HF are episodes of profound consequence to the patient. Health, emotional well-being, quality of life, work status, and long-term prognosis are affected by these medical events. Successful treatment via initiation and optimization of medical therapy not only improves patients’ immediate symptoms but also their long- term prognosis.115–117 One of the important keys to success for the practitioner is to ensure that the indicated, evidence- based therapies are administered appropriately and in a timely fashion. After 20 years of clinical trials data, many centers still fall short of this goal. This is probably a combination of the incomplete penetration of recent guidelines into routine medical practice, as well as difficulty in applying guidelines to patients with complex hemodynamic derangements and multiple comorbidities. Furthermore, despite years of HF clinical research, many basic questions remain unresolved. As a result, physicians must still rely on their own clinical experience to treat this prevalent disease.

As mentioned previously, the AHA/ACC guidelines for the management of HF were updated in 2009.5 Although the evidence base for patients with AHFS is limited, with most recommendations stemming from expert consensus (level C), these guidelines still provide direction for clinicians caring for stabilized AHFS patients as they are being transitioned from the ED to an inpatient bed, and eventually to outpatient care.

Inpatient Therapy for AHFS Treatment of pulmonary congestion and the resultant symp- toms has remained the cornerstone of AHFS therapy for over 50 years. Pulmonary congestion, even though it is sometimes difficult to assess, is a symptom of elevated left atrial pressure. Clinicians currently lack a simple, inexpensive, accurate, reliable, and noninvasive means of assessing this target for therapy. A variety of techniques such as physical examination, echocardiography, pulmonary artery catheter- ization, implanted hemodynamic monitors, and thoracic im- pedance have been tested and found to have limited utility in the management of AHFS.118 –123 There remains no reliable means of identifying when to start diuretics and when to withhold them before obvious clinical signs, such as renal dysfunction or hypotension, develop.

Morbidity and Mortality in Hospitalized Patients With AHFS The average risk of death during hospital admission for AHFS is approximately 4% based on data from both ADHERE and OPTIMZE-HF.11,63 Patients who are admitted with AHFS and require the administration of vasoactive drugs may have a poorer prognosis and an increased risk of death.9,124 Patients requiring the use of inotropic agents had a mortality rate of 12% to 13% in ADHERE.9 Intravenous vasodilators have demonstrated fa- vorable acute hemodynamic effects but the impact on long-term morbidity and mortality remains unclear. The use of vasodilators has been associated with a mortality risk of 4.7% for nitroglyc- erin and 7.1% for nesiritide.9 Risk factors for increased mortality during hospitalization include increasing age, elevated heart rate,

Hospitalization of the patient with AHFS defines a point on the continuum of their disease process. Admission for treat-

hyponatremia, hypotension, left ventricular systolic dysfunction, elevated serum creatinine, blood urea nitrogen, natriuretic pep-

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