Heart Failure: Epidemiology, Characteristics, and Prognosis

Justin Ezekowitz

INTRODUCTION

Heart failure (HF) is a major public health problem affecting up to 2% of the population and ˜10% of elderly individuals in the Western world¹,² and over 37.7 million globally.³

The definitions and taxonomies have evolved significantly from the first description of the disease by the German pathologist, Rudolf Virchow in 1858, and it is expected to evolve further as we make progress in understanding the pathophysiology of the disease.⁴ This change of definitions may have contributed partly to the change of the epidemiological statistics over time.

The statistics reported in different studies relied heavily on the diagnostic criteria, the method of ascertaining diagnosis, and the population under study (elderly vs all, hospitalized patients vs all, trial-based vs population-based, etc). Several criteria—including the Framingham,⁵ Boston (aka Carlson),⁶ Gothenburg,⁷ Duke,⁸ and European Society of Cardiology (ESC) criteria⁹—have been developed over several decades to help us with the task of diagnosing HF, with variable performances in the validation studies (Table 65.1).

CLASSIFICATIONS OF HEART FAILURE

Midrange Ejection Fraction, Preserved Ejection Fraction, and Reduced Ejection Fraction

One of the classifications widely used over the last few decades in randomized clinical trials (RCTs) and in practice guidelines is classifying symptomatic patients with HF based on their left ventricular ejection fraction (LVEF) status into those with preserved (HFpEF), midrange (HFmrEF), or reduced (HFrEF) ejection fraction, which are defined as LVEF ≥50%, 40% to 49%, and less than 40%, respectively (Table 65.2). It is important to note that although HFrEF generally refers to systolic HF and contractile dysfunction, the patients with HFrEF may have both systolic and diastolic dysfunctions. On the other hand, HFpEF does not necessarily imply diastolic HF.¹⁰ Diastolic function, which is about ventricular relaxation and filling during diastole, might be impaired in HFpEF, and they may have overlapping clinical features, but the two terms are not equivalent to each other. On the other hand, abnormalities of systolic function such as impaired global longitudinal strain have been reported in patients with HFpEF.¹¹ Although the above-mentioned groups have similarities in terms of clinical symptoms and presentation, they differ in terms of demographics, underlying factors, structural heart abnormalities, and response to therapies.¹²

Stages of Heart Failure

One of the widely used functional classifications of HF is the New York Heart Association (NYHA) functional classification, which classifies patients predominantly based on HF symptoms and functional limitations. Hence, it helps in assessing the severity of patient symptoms, indicating the need for escalation of HF treatments, and evaluating the response to treatment (Table 65.3). Of note, patients can move back and forth between the different NYHA classes.

Subsequently, the American College of Cardiology (ACC)/American Heart Association (AHA) guideline suggested a classification based on disease progression, which classifies patients with HF into four stages from A to D (Table 65.3).¹³

Risk Factors

Many risk factors have been evaluated and identified through different cohort studies. To name a few, hypertension (present in 44%-91% of patients at incident HF diagnosis), diabetes mellitus (DM; 18%-23%), coronary artery disease (CAD; 29%-63%), obesity (25%), smoking (51%), arrhythmias, congenital heart diseases and cardiomyopathies.¹²,¹⁴ The above-mentioned traditional risk factors have been responsible for over half of incident HF cases in the Olmsted County, MN cohort.¹⁵ Hypertension, older age, female sex, and DM are the greatest risk factors for HFpEF. Although the HFpEF population is shown to be more obese than HFrEF population, body mass index was a risk factor for both, and there was no difference in its prognostic effect on the incidence of HFpEF and HFrEF.¹⁶ Dyslipidemia, inflammation, hyperglycemia, exposure to cardiotoxic agents (such as alcohol, amphetamines, chemotherapy, and radiation therapy), micronutrient deficiency, family history of HF or other cardiovascular diseases, and poorer socioeconomic status are other risk factors for HF.¹⁴

One-third of the U.S.population has at least one risk factor for HF.¹⁷ The number of risk factors per person increased by 30% from 1979 to 2002 in patients with incident HF.¹⁸ Prevention and controlling these risk factors can lead to a reduction in the incidence of HF, although the reduction of these might be a herculean endeavor itself. According to the National

Health and Nutrition Examination Survey (NHANES) study, the prevalence of hypertension, myocardial infarction, and smoking has declined, but the prevalence of obesity and DM has increased over the past few decades.¹⁹,²⁰

TABLE 65.1 Different Diagnostic Criteria for the Diagnosis of Patients With Heart Failure

Diagnostic Model	Components	Diagnosis of HF
Framingham criteria	Major criteria: acute pulmonary edema, jugular vein distension, hepatojugular reflux, paroxysmal nocturnal dyspnea or orthopnea, pulmonary rales, S3 heart sound, weight loss >4.5 kg in 5 days in response to treatment, cardiomegaly on chest x-ray Minor criteria: ankle edema, dyspnea on exertion, hepatomegaly, nocturnal cough, pleural effusion, tachycardia, weight loss >4.5 kg in 5 days with diuretics	≥2 major or 1 major and ≥2 minor criteria
Boston criteria	History (dyspnea at rest, orthopnea, paroxysmal nocturnal dyspnea, dyspnea while walking, dyspnea on climbing, leg fatigue while walking), physical examination (tachycardia, jugular vein distension, lung crackles, wheezing, S3), and chest radiography (alveolar pulmonary edema, interstitial pulmonary edema, bilateral pleural effusion, cardiothoracic ratio ≥0.5, upper zone flow redistribution) criteria	Definite HF: 8-12 points; Possible HF: 5-7 points; Unlikely HF: ≤4 points
Gothenburg criteria	Cardiac score: coronary heart disease in past, within past year, angina in past, within past year, leg edema, pulmonary rales, atrial fibrillation, Pulmonary disease score: history of bronchitis in past, chronic bronchitis in past year, asthma, asthma in past year, coughing, phlegm, or wheezing, rhonchi at physical examination, Therapy score: history of digoxin or diuretic use	Graded 0 if all scores zero, Grade 1 (latent) if cardiac score >0 but other two zero, Grade 2 (manifest) if cardiac score >0 and either pulmonary or therapy score >0, Grade 3 if all scores >0, and Grade 4 if death owing to heart failure
Duke criteria	Cardiomegaly by radiography, S3 gallop, other congestive heart symptoms including dyspnea, orthopnea, paroxysmal nocturnal dyspnea, edema in history or by examination, history of inotrope therapy, rales, tachycardia, jugular vein distension, hepatojugular reflux
ESC criteria	Clinical history (orthopnea, paroxysmal nocturnal dyspnea, history of CAD, history of arterial hypertension, exposure to cardiotoxic drugs/radiation, use of diuretics), physical examination (rales, bilateral ankle edema, heart murmurs, jugular vein distension, laterally displaced and broadened apical beat), any abnormality on ECG, elevated natriuretic peptides (BNP ≥ 35 pg/mL and NT-proBNP ≥ 125 pg/mL), echocardiography	HF unlikely if all criteria absent or if at least one clinical/physical examination/ECG criterion was present but with no elevated serum natriuretic peptide level or with elevated serum natriuretic peptide level but no findings in favor of HF on echocardiography
BNP, brain-type natriuretic peptide; CAD, coronary artery disease; ECG, electrocardiogram; ESC, European Society of Cardiology; HF, heart failure; NT-proBNP, N-terminal pro-brain-type natriuretic peptide.

TABLE 65.2 The Classification of HF Based on Left Ventricular Ejection Fraction Status

	LVEF	Other Criteria	Proportion	Clinical Features
HFrEF	<40%	–	40%-50%	Systolic HF, but diastolic dysfunction may also present
HFmrEF	40%-49%	Elevated natriuretic peptide levels, and structural cardiac disease or diastolic dysfunction	10%-20%	Either borderline HFpEF in transition to HFrEF or patients with recovered HFrEF; Hence, sharing features of both HFrEF and HFpEF
HFpEF	≥50%	Elevated natriuretic peptide levels, and structural cardiac disease or diastolic dysfunction	40%-50%	Predominantly older, more often female with more comorbidities such as hypertension, diabetes, atrial fibrillation, or obesity, but less ischemic heart diseases compared to patients with HFrEF
HF, heart failure; HFmrEF, heart failure with midrange ejection fraction; HFpEF, heart failure with preserved ejection fraction; HFrEF, heart failure with reduced ejection fraction; LVEF, left ventricular ejection fraction.

TABLE 65.3 New York Heart Association and American College of Cardiology/American Heart Association Functional Classifications of Patients With Heart Failure

	Class	Definition
NYHA	Class I	Cardiac disease without limitations of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, shortness of breath, or chest pain.
	Class II	Cardiac disease resulting in a slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitation, shortness of breath, or chest pain.
	Class III	Cardiac disease resulting in marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, palpitation, shortness of breath, or chest pain.
	Class IV	Cardiac disease with inability to conduct physical activity without discomfort. Symptoms may be present even at rest.
ACC/AHA	Stage A	Patients at risk of heart failure (ie, those with hypertension, diabetes, or atherosclerotic coronary disease) who have not yet developed structural heart changes
	Stage B	Patients have structural heart disease (ie, reduced ejection fraction, left ventricular hypertrophy, chamber enlargement) but have not yet developed signs or symptoms of heart failure.
	Stage C	Patients with clinical heart failure
	Stage D	Patients with advanced heart failure requiring advanced interventions such as cardiac resynchronization therapy, left ventricular assist device, or heart transplantation
ACC, American College of Cardiology; AHA, American Heart Association; NYHA, New York Heart Association.

HF could result from a wide range of etiologies, from hereditary and structural conditions to infective and inflammatory causes. Causes may originate from the cardiovascular system or other organ systems. The Global Burden of Disease (GBD) study has identified up to 17 etiologies for HF.²¹ The underlying etiologies and risk factors may vary from one age, sex, or racial group to another. Ischemic heart disease and chronic obstructive pulmonary disease (COPD) are the leading etiologies for HF in high-income countries, whereas major underlying etiologies in the low-income countries have been hypertensive heart disease, rheumatic heart disease, cardiomyopathy, and myocarditis.²²

Ischemic Heart Disease

HF has a prevalence of ˜20% in patients with ischemic heart disease, whereas the prevalence is significantly lower (1%-2%) in those without ischemic heart disease.²³ This etiology is responsible for two-thirds of HFrEF cases and a third of HFpEF cases.²⁴,²⁵ According to the GBD study, the prevalence of ischemic HF increased from 240 per 100,000 person-years in 1990 to 270 per 100,000 person-years in 2010 among men, but was relatively stable among women (190 per 100,000 person-years).²⁶

Hypertensive Heart Disease

Hypertension is a risk factor but is also one of the most frequent comorbidities in HF.²⁷,²⁸ Besides community-based cohort studies, having subsequent HF among the end points of RCTs on hypertension has provided the opportunity to know more about the effects of these conditions on the development or worsening of HF. A majority of patients with HF (73.6% in HFrEF and 89.3% in HFpEF according to Olmsted County study)²⁵ have hypertension. Although patients with blood pressure greater than 160/90 mm Hg had double the risk of HF compared to those with blood pressure less than 140/90 mm Hg,²⁹ medical treatment is shown to reduce the risk in both patients with moderate and severe hypertension by 87%.³⁰ However, the management has been suboptimal in many cases, for example, in the Prospective Urban Rural Epidemiology (PURE) study, only 46.7% and 31.7% of patients with hypertension were receiving treatment and only 19% and 12.7% were at the target blood pressure range, respectively, in high- and low-income countries.³¹

Valvular Heart Disease

Moderate to severe valve disease is estimated to be present in 2.5% of the U.S. population.³² In a prospective study of adult patients with moderate to severe native or acquired valvular heart disease, congestive HF was present in 21.3% of patients at the time of valvular intervention.³³ Among community patients with suspected HF in the United Kingdom (UK), 37.5%, 11.3%, and 2.7% were shown to have mild, moderate, and severe valvular disease, respectively.³⁴ The highest population-attributable risk related to the valvular disease is rheumatic heart disease, which is reduced substantially in the developed world, owing to improved living conditions and increased antibiotic therapy. The incidence rate of rheumatic fever varies from 1 case per 100,000 person-years in the developed countries to greater than 100 cases per 100,000 person-years in sub-Saharan Africa.³⁵

Cardiomyopathies

Cardiomyopathy generally refers to the structural and functional abnormalities of the heart muscle in the absence of CAD, hypertension, valvular heart disease, and congenital heart disease that may progress to HF, and is categorized based on morphology and function into five phenotypes of hypertrophic, dilated, restrictive, arrhythmogenic right ventricular, and unclassified cardiomyopathies.⁴,³⁶ Cardiomyopathies are major causes of HF in the Western world.¹³ Although the number of deaths secondary to cardiomyopathy has increased by 40.8% from 1990 to 2010, the age-standardized death rates were decreased by 9.8% from 6.7 to 6.1 per 100,000 in the same time period.³⁷

OTHER IMPORTANT COMORBIDITIES

Coexisting comorbidities such as CAD, COPD, DM, renal failure, and pneumonia or a combination of those are prevalent in patients with HF (Figure 65.1)⁸⁵. They may contribute to the development of disease as mentioned above, make the diagnosis more complex, worsen the severity of HF symptoms, interact with the treatment effects, and are sometimes, but not always, harbingers of poorer outcomes.

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

Tags: Cardiovascular Medicine and Surgery

May 8, 2022 | Posted by drzezo in CARDIOLOGY | Comments Off

Thoracic Key

Fastest Thoracic Insight Engine

Heart Failure: Epidemiology, Characteristics, and Prognosis

Related

Stay updated, free articles. Join our Telegram channel

Full access? Get Clinical Tree

Thoracic Key

Fastest Thoracic Insight Engine

Heart Failure: Epidemiology, Characteristics, and Prognosis

Share this:

Related

Related posts:

Stay updated, free articles. Join our Telegram channel

Full access? Get Clinical Tree