HEART FAILURE DIAGNOSIS AND EPIDEMIOLOGY

CHAPTER 1


Heart Failure Diagnosis and Epidemiology



FAST FACTS


Heart failure diagnosis is usually based on Framingham criteria: either two major, or one major and two minor criteria. Less severe heart failure can manifest without fulfilling these criteria.


The ACCF/AHA 4 Stages (A, B, C, D) and the New York Heart Association functional classifications of heart failure (I–IV) are complementary.


 


In the United States:


Heart failure annual incidence increased from 250,000 cases in 1970 to 825,000 cases in 2010, contributing to a prevalence of 5.1 million individuals ≥ 20 years of age.


Lifetime risk for developing heart failure at the age of 40 years and greater is 1 in 5 in both men and women.


Between 1979 and 2010, annual heart failure hospitalization rates tripled, with 1,023,000 hospital discharges in 2010.


In the Medicare population, heart failure is the most common cause for hospitalization.


After heart failure discharge, readmission rates for recurrent heart failure or other causes are 24% within the first month and 50% within the first 6 months.


In 2012, direct and indirect medical costs associated with heart failure were $30.7 billion.


One in 9 deaths includes heart failure on the death certificate.


“The prime candidates for the development of heart failure are patients with hypertension in whom death from stroke has been prevented by antihypertensive therapy and survivors of acute myocardial infarction who have been spared death from arrhythmia.”


—Eugene Braunwald, Shattuck Lecture 19971


Heart Failure Recognition


The diagnosis of heart failure may emerge from history, physical examination, or laboratory data.


CLINICAL CRITERIA OF HEART FAILURE


The Framingham study defined useful clinical criteria to identify patients with heart failure (Table 1.1). Patients not fulfilling the Framingham criteria can still have heart failure, albeit less severe disease, if they have symptoms of dyspnea or fatigue associated with structural or functional left ventricular abnormalities.2 Specifically, heart failure may be present when an individual has physical limitations at rest or with activity due to inadequate cardiac output or increased left or right ventricular filling pressures. Blood levels of biomarkers, such as B-type natriuretic peptide (BNP), supplement clinical findings to characterize the presence and severity of heart failure.


TABLE 1.1    Framingham diagnostic criteria for heart failure. The diagnosis of heart failure, in the Framingham heart failure study, required two major or one major and two concurrent minor criteria. Minor criteria cannot be attributed to another medical condition.4 Source: Adapted from the New England Journal of Medicine, with permission.


































MAJOR CRITERIA


MINOR CRITERIA


Acute pulmonary edema


Dyspnea on exertion


Paroxysmal nocturnal dyspnea or orthopnea


Night cough


Neck-vein distention


Tachycardia (> 120 beats/min)


Rales


Pleural effusion


S3 gallop


Hepatomegaly


Abdominojugular reflux


Ankle edema


Cardiomegaly on chest x-ray


Vital capacity decrease (1/3 from max)


Increased venous pressure (> 16 cm H2O)


Weight loss*


Weight loss*


 


*Weight loss > 4.5 kg 5 days into treatment can be classified as a major or minor criterion


HEART FAILURE CLASSIFICATION


In 1928, the New York Heart Association (NYHA) functional classification was proposed to classify the severity of heart failure based on symptoms.3 In this system, severity ranges from no limitation of functional activity (Class I), slight limitation of functional activity (Class II), marked limitation of functional activity (Class III), to the presence of symptoms at rest (Class IV). Although useful, to characterize a patient’s functional impairment at any point in time and provide an index that correlates with prognosis, the system is limited by the potential for a patient’s class to either worsen or improve rapidly in response to acute exacerbations or treatments (Figure 1.1).


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FIGURE 1.1    The ACCF/AHA stages of heart failure compared to the NYHA classification. Whereas NYHA functional class can wax and wane, the ACCF/AHA Stages (A–D) can only advance, usually with greater underlying structural and functional cardiac impairment.


Partly to address this potential for fluctuation in NYHA patient classification, in 2001 the American College of Cardiology Foundation and the American Heart Association published a four-component staging of heart failure in which progression occurs in only one direction encompassing risk factors (Stage A) to end-stage heart disease (Stage D).5 This classification was most recently updated in 2013.6 The previous New York Heart Association functional class, based solely on symptoms, can still describe the current functional status of a patient in Stages B through D. Especially in Stage C, however, any of the three symptomatic NYHA classifications (Class II, III, or IV) may repeatedly arise, resolve, and recur (Figure 1.2).


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FIGURE 1.2    The ACCF/AHA stages of heart failure compared to the NYHA classification. With treatment, a heart failure patient can become asymptomatic, but will remain Stage C.


Stage B is defined as development of structural heart disease in patients who never manifest symptoms or signs of heart failure.5 Most patients with a diagnosis of heart failure with either past or current symptoms are considered Stage C. Approximately 1% of patients with heart failure have progressed to an advanced Stage D.2


Epidemiology


Heart failure is increasing, particularly as a disease of aging. The prevalence also varies by race and ethnicity.


PANDEMIC OF HEART FAILURE


As patients survive the progression of acute and chronic cardiovascular disease, the subsequent development of heart failure accompanied by chronic, maladaptive ventricular remodeling becomes more common.7,8 Insults to the kidneys and peripheral vasculature contribute to this progression. Since 1970, in the United States, heart failure annual incidence has increased markedly (Figure 1.3).


image


FIGURE 1.3    Increase in incidence of heart failure in United States since 1970.9,10


HEART FAILURE AS A DISEASE OF AGING


After the age of 20, the prevalence of heart failure approximately doubles with each decade of life (Figure 1.4

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Jul 26, 2016 | Posted by in CARDIOLOGY | Comments Off on HEART FAILURE DIAGNOSIS AND EPIDEMIOLOGY

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