US Pharm. 2023;48(11):42-45.ABSTRACT: Cardiac asthma is a pulmonary condition secondary to fluid overload due to left-ventricular failure associated with heart failure (HF). The symptoms of cardiac asthma are like that of bronchial asthma and can be difficult to distinguish; however, defining symptoms include frothy cough and sputum with pulmonary rales, especially occurring at night. Despite different underlying pathology, HF patients can be prescribed short-acting beta-agonist inhalers, or rescue inhalers, that are used to treat bronchial asthma exacerbations to help relieve symptoms of cardiac asthma. Increased use of rescue inhalers can be monitored by pharmacists to assess potential HF exacerbations that can indicate a necessary escalation in medication therapy to improve symptoms and quality of life and decrease mortality.
Heart failure (HF) is a chronic, progressive disease that affects about 6 million patients in the United States and accounts for over $30 billion of annual healthcare costs, including direct and indirect medical costs. There is no cure, and HF drastically affects quality of life, requiring collaboration between pharmacists and specialist providers to minimize exacerbations and improve quality of life and patient outcomes through medication therapy, patient education, and routine monitoring.
HF inhibits the ability of the heart to pump blood effectively due to structural or functional complications that alter ventricular filling or pumping of blood to the whole body. Despite being a cardiomyopathy, the complications of HF affect the entire body, with symptoms such as edema, hypertension, pulmonary edema, dyspnea, and cardiac asthma.1,2
Cardiac asthma is a nuanced complication of the pulmonary pathology of HF. Due to the fluid overload in HF patients, despite diuretic use, excess fluid tends to collect in the lungs, causing dyspnea, frothy sputum, bubbling rales, and sleep disruption due to manifestation of symptoms at night, particularly when patients are lying down. Cardiac asthma is an obstruction of airways due to an excess of fluid that enters the pulmonary system. Respiratory stimulation due to underlying pathological factors can exacerbate the fluid overload of the diseased left ventricle, causing pulmonary edema secondary to HF.3
In contrast, bronchial asthma is a reversible inflammation of airways due to environmental irritants and allergens. Hyperresponsiveness of the airway causes acute and reversible airflow restriction that can be treated by the patient using a rescue inhaler containing a beta-agonist (TABLE 1).4,5
The underlying etiology of cardiac asthma is secondary to HF exacerbations; however, studies have shown that the use of beta-agonists provides temporary relief for cardiac asthma. Following this notion, the use of rescue inhalers can identify an HF exacerbation, similarly to how asthma exacerbations can be identified based on how long each inhaler lasts a patient.3,6
Overview of HF
HF is a complex disease with a continuous progression, where quality of life and functional capacity of a patient can decline greatly. Because there is no cure, it is important to provide proper diagnosis, monitoring, and pharmacologic therapy to help patients with HF maintain functionality and quality of life despite disease progression.2
HF can cause fluid overload, manifesting as edema in the extremities or as pulmonary congestion, causing airway restriction. Restrictive ventilatory abnormalities have been noted in about 80% of patients with both acute and chronic HF. Impaired airway flow secondary to HF has been shown to increase mortality and decrease health outcomes, especially in worsening HF.2,7,8
The hemodynamic congestion seen has deleterious effects on left-ventricular remodeling and can contribute to ischemia and diastolic dysfunction. Patients with pulmonary congestion must be reevaluated to establish better disease management with additional therapeutic agents.9,10
HF is diagnosed using laboratory values, including proBNP, as well as evaluation of clinical history, a transthoracic echocardiogram, ECG, and additional testing if necessary. Based on left-ventricular ejection fraction (LVEF), patients can be diagnosed with three types of HF: HFrEF (LVEF 40% or below); HFmrEF (LVEF of 41%-49%); or HFpEF (LVEF 50% or higher). HF patients are also staged, which dictates the need for initiating pharmacologic treatment. An HF patient’s functional capacity can be classified by the New York Heart Association (NYHA) classification system at stage C (symptomatic HF) and stage D (advanced HF) of the disease. NYHA is used to determine treatment strategies for patients. NYHA class is established at baseline and is continually updated through continuum of care and can indicate how well a stage C HF patient is controlled on their medication regimen.2
Stage C HF, or symptomatic HF, dictates the point at which a medication regimen is started. This usually consists of five medications: a beta-blocker; a mineralocorticoid receptor antagonist; a sodium-glucose cotransporter-2 inhibitor; a diuretic as needed; an angiotensin receptor/neprilysin inhibitor (ARNi) (NYHA II-III); an angiotensin-converting-enzyme inhibitor; or an angiotensin receptor blocker (NYHA II-IV).10 Maximum doses of each medication are based on patient tolerance to therapy; however, the disease still progresses despite the benefits of the medication regimen.
Worsening of symptoms can be caused by comorbidities, lifestyle factors, or the environment. Worsening and progression can lead to stage D HF, where a patient is on medication but is still symptomatic with acute exacerbations that can manifest as pulmonary complications. These complications may lead to asthma-like symptoms, dictating the need for use of a rescue inhaler to relieve dyspnea.2
Rescue inhalers are a short-term relief to a greater underlying problem, such as in bronchial asthma, where increased use can indicate a need for an escalation of therapy. Though not indicated for cardiac asthma, HF patients on guideline-dictated medical therapy who are experiencing symptoms of airway obstruction may acutely benefit from beta-2 agonist use. Beta-2 agonists also pose a hypokalemia risk that must be evaluated before starting diuretics, such as IV furosemide, which are used for acute care of pulmonary exacerbation in HF patients admitted to the hospital. The American Heart Association warns that agents such as albuterol should be used with caution in patients with cardiovascular disease, though the agents may be beneficial for symptomatic treatment.2,6,11
Assessing Inhaler Use
Asthma exacerbations are an acute or subacute worsening of symptoms and lung function from a patient’s usual pulmonary status. Rescue inhalers, or short-acting beta-agonists (SABAs), are one of the main treatments for asthma in both children and adults and have been a helpful tool in assessing when a patient’s asthma is worsening and therapy adjustment is needed. Beta-agonists, such as albuterol and levalbuterol, bind beta-2 receptors in the lungs and airways and promote bronchial dilation and airway relaxation, which improves airflow and dissipates symptoms.6
SABA inhalers have dose counters on the body of the inhaler that identify how many doses are left in the canister. The dose counter can be used as a tool to identify how often an asthma patient is using their inhaler, indicating how controlled their asthma is. A traditional SABA rescue inhaler has 100 to 200 doses and is used as one to two puffs every 4 to 6 hours as needed for exacerbation, with a maximum of eight puffs per day. If used at this frequency every day, the inhaler lasts a patient 25 days. In community practice, frequency of use and refill timing can indicate that the patient is experiencing a worsening of symptoms.
The Global Initiative for Asthma (GINA) guideline indicates that regular use beyond 1 to 2 days requires evaluation and possible escalation of therapy of the controller treatment. A standardized threshold of 150 puffs per year of a rescue inhaler, approximately two canisters per year, has been established by the GINA guideline to identify patients who have uncontrolled asthma and require an escalation of therapy. There is no benefit in using albuterol and levalbuterol on a regular, scheduled basis. Scheduled use has been shown to increase mortality. Rescue inhalers are meant for the relief of symptoms resulting from a reversible airway obstruction that is due to an inflammatory mechanism restricting airflow. Beta-agonists provide airway dilation that allows for symptomatic relief.5,6,12-14
In cardiac asthma, pulmonary symptoms are due to pulmonary edema, which cannot be acutely resolved using self-treatment with a rescue inhaler and requires medical attention. However, data suggest that HF patients may benefit from SABA use for temporary relief of symptoms and improved quality of life despite hypokalemia risk, and these medications should be used with caution according to the American Heart Association.11,15
Increased use of rescue inhalers in HF patients can help identify possible exacerbations if there has been a lack of response to increased SABA therapy. Identification of exacerbations by assessing inhaler use in HF patients can help to stage intervention. Pulmonary congestion secondary to HF results in a manifestation of cardiac asthma symptoms and indicates poor pharmacologic control, requiring an escalation in therapy.
The use of rescue inhalers and beta-2 agonists in treating patients with cardiac asthma indicates a worsening of HF status, and these individuals must be admitted to a hospital for acute ICU treatment of pulmonary congestion and evaluation of HF status by a specialist to assess the need for therapy escalation.2,6,11
Role of the Pharmacist
Pharmacists are key healthcare providers who can help improve health outcomes in multiple disease states. In HF patients, pharmacists can help tailor medication regimens, manage side effects, decrease polypharmacy, and emphasize lifestyle factors. The frequent use of SABA inhalers in asthma patients is a clinical tool used by pharmacists to assess possible worsening or progression of asthma based on the patient’s medication profile. Overutilization of SABA inhalers can be an indicator of pulmonary complications secondary to HF exacerbations. Early intervention and referral to a cardiologist can significantly improve health outcomes, decrease mortality, and increase both quality of life and life expectancy.6,12,13
Community pharmacists can gather patient health information at the point of care during refill requests or medication pickup to gain clarity on what is happening with their patients. Interviewing patients on the types of symptoms they are experiencing and how often they occur helps in distinguishing between bronchial asthma and cardiac asthma secondary to HF exacerbation.
Additionally, a patient’s maintenance medication profile should be compared with current guidelines for their diagnosed disease state, as well as for assessing adherence and side effects, along with environmental factors and lifestyle changes that could be causing complications. HF is a lifelong diagnosis. While there is currently no cure, pharmacists are keenly positioned to collaborate with both patients and other healthcare providers to improve health outcomes in HF by staging early interventions that slow disease progression and improve quality of life.2-4,6
Rescue inhalers are beneficial for acute relief in both bronchial and cardiac asthma; however, increased reliance upon a rescue inhaler in HF patients can indicate an HF exacerbation or need for escalation of therapy. Pharmacists possess the communication skills necessary to gather pertinent patient health information to distinguish between possible bronchial asthma or pulmonary edema due to fluid overload in HF. These patients require very close monitoring to slow progression and maintain a higher quality of life. Patient education about the disease state and medication regimen allows patients to self-identify and manage their own health. Collaboration between pharmacists and specialist providers helps to minimize exacerbations and improve patient outcomes by better controlling HF through medication therapy, patient education, and routine monitoring.
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