COPD refers to two lung diseases, chronic bronchitis and emphysema, and is the 4th ranking cause of death in the US; it claimed the lives of 120,555 Americans in 2002. While more than 10.7 million US adults (aged 18 and above) were estimated to have COPD in 2003, 24 million US adults have evidence of impaired lung function, indicating an under-diagnosis of COPD. Even more alarmingly, the death rate of COPD has doubled over the past 30 years while the death rates for the three leading causes of death (heart disease, cancer and stroke) have decreased by over 50 percent. 2004 annual cost associated with COPD according to National Heart, Lung, and Blood Institute was $37.2 billion.
Worldwide, lung disease is equally devastating. Respiratory diseases are the leading cause of death in Europe. Developing countries such as China with large and growing tobacco usage are driving worldwide growth rates. This substantial increase in the global burden of COPD reflects, in large part, the historical increase in tobacco use worldwide and the changing age structure of populations in developing countries.
COPD is characterized by obstruction to airflow that interferes with normal breathing. Specifically, chronic bronchitis is the inflammation and eventual scarring of the lining of the bronchial tubes and emphysema begins with the destruction of air sacs (alveoli) in the lungs where oxygen from the air is exchanged for carbon dioxide in the blood. Damage to the air sacs is irreversible and results in permanent holes in the tissues of the lower lungs. Sufferers literally fight for breath.
Though there are treatments that can improve a patient’s quality of life, COPD lung damage is irreversible. Smoking cessation is the single most effective – and cost effective – intervention to reduce the risk of developing COPD and slow its progression.
Pharmacologic treatments including bronchodilators, oral steroids, antibiotics and expectorants can improve and prevent symptoms, reduce the frequency and severity of exacerbations, improve health status and improve exercise tolerance.
Non-pharmacologic treatment such as pulmonary rehabilitation, oxygen therapy and surgical interventions can improve a person’s quality of life. Close to one million persons living in the US are on long-term oxygen therapy (>15 hours per day).
Lung Volume Reduction Surgery (LVRS) is still considered to be experimental and is not appropriate for many patients.
Lung transplantation is now being done and may be a more readily available option in the future. However, lung transplantation has very substantial limitations, including organ shortage, operative mortality, serious post-operative complications and hospitalization costs. Lung transplantation also does not demonstrate a meaningful survival benefit after two years.
Cystic Fibrosis (CF)
Cystic fibrosis is a lifelong, hereditary disease that causes thick, sticky mucus to form in the lungs, pancreas and other organs and affects approximately 30,000 Americans. In 90 percent of cases, the airways are affected as this mucus tends to block the airways, causing lung damage and making breathing difficult.
Today, according to the CF Foundation’s National Patient Registry, the median age of survival for people with CF is in the late 30s and more than 40 percent of the CF population is age 18 and older. Many people with CF are living into their 30s, 40s, 50s and beyond. In the last four years alone, more than five years have been added to the median survival age of CF patients.
Although CF begins at conception, symptoms may not appear for several years. Treatment options depend upon the stage of the disease and the organs involved.
Chest physical therapy to clear mucus from the lungs is an important part of the daily CF treatment regimen.
Bronchodilators have helped to deal with chronic dysfunction and antibiotics are used to treat lung infections and are given intravenously, with pills and/or medicated vapors, which are inhaled to open up clogged airways. Corticosteroids and other anti-inflammatory drugs have been evaluated in several studies.
In some cases, lung transplantation has been attempted; over the last ten years, double-lung transplantation has replaced heart-lung as the preferred procedure, and there has been steady improvement in the outlook with refinements in both surgical techniques and anti-rejection measures. As in other areas of medicine, there is a lack of donors, and there are lengthy waiting lists.
Pulmonary Fibrosis
Pulmonary fibrosis, which involves scarring of the lungs, is estimated to affect five million people worldwide. In the United States there are over 200,000 patients with pulmonary fibrosis; of these, 40,000 expire annually.
Because the origin and development of the disease are not completely understood, misdiagnosis is common. Varying terminology and lack of standard diagnostic criteria have complicated the gathering of accurate statistics about people with pulmonary fibrosis. As a consequence, the actual numbers may be significantly higher.
With pulmonary fibrosis the air sacs of the lungs become replaced by fibrotic tissue. When the scar forms, the tissue becomes thicker causing an irreversible loss of the tissue’s ability to transfer oxygen into the bloodstream. While diagnoses have ranged from age seven to the eighties, typically patients are in their forties and fifties when diagnosed.
Although the exact cause of pulmonary fibrosis remains unknown, associations have been made with the following:
Genetic predisposition.
Reaction to microscopic injury to the lung.
Inhaled environmental and occupational pollutants.
Diseases such as scleroderma, rheumatoid arthritis, lupus and sarcoidosis.
Certain medications.
Therapeutic radiation.
There are currently no effective treatments or a cure for pulmonary fibrosis. Pulmonary fibrosis is a very complex disease and the predictions of longevity of patients after diagnosis vary greatly.
Pharmacological agents designed to treat lung scarring are still in the experimental phase and the treatments intended to suppress inflammation have only limited success in reducing the fibrotic progress.
Supplemental oxygen improves the quality of life and exercise capacity.
Single lung transplant may be considered for some patients.
Primary and Secondary Pulmonary Hypertension (PPH)
Primary pulmonary hypertension (PPH) is a relatively rare disease that results in the progressive narrowing of the blood vessels of the lungs, causing high blood pressure in these blood vessels and eventually leading to heart failure. Secondary pulmonary hypertension (SPH) is the result of other types of lung disease, abnormal breathing processes or heart disease. A common cause of SPH are the breathing disorders emphysema and bronchitis. Other less frequent causes are the inflammatory or collagen vascular diseases such as scleroderma, CREST syndrome or systemic lupus erythematosus (SLE). Congenital heart diseases that cause shunting of extra blood through the lungs like ventricular and atrial septal defects, chronic pulmonary thromboembolism (old blood clots in the pulmonary artery), HIV infection, liver disease and diet drugs like fenfluramine and dexfenfluramine are also causes of pulmonary hypertension.
While in 2002 there were 60,000 hospital discharges in which one of the diagnoses was PPH and 3,549 deaths were attributed to primary pulmonary hypertension, the true incidence of PPH is unknown.
Primary pulmonary hypertension is usually progressive and ultimately fatal. Unfortunately, diagnosis may be delayed for several years since initial symptoms of PPH may be very minor. The median duration of survival after the diagnosis of primary pulmonary hypertension is 2.8 years, but this figure is highly variable.
Although primary pulmonary hypertension is treated with number of drugs, none of the drugs cure or halt the progression of his disease. New treatments, however, are available which have significantly improved prognosis.
Some patients take vasodilators, which help to dilate the blood vessels in the lungs, reducing the blood pressure in them. Anticoagulants may be used to decrease the tendency of the blood to clot in the lungs.
Lung transplantation is an option in some patients younger than 65 years who have pulmonary hypertension that does not respond to medical management.
The prognosis for patients with secondary pulmonary hypertension depends on the underlying disease, as well as right ventricular function. For instance, patients with COPD and moderate airflow obstruction have a three-year mortality rate of 50 percent after the onset of right ventricular failure.
Address the World’s Third Leading Killer
The growing incidence of diseases of the lung presents enormous challenges to patients, their families, physicians and society, with very limited therapeutic options.
COPD, a class of respiratory diseases that includes emphysema, bronchitis and asthma, already afflicts 35 million sufferers in the U.S.
Lung disease is America’s number three killer, responsible for one in seven deaths (349,000 annually), and the death rate has been continuously increasing.
By the year 2020 the World Health Organization estimates that COPD will be the third leading cause of death worldwide.
It is the only major chronic disease with an increasing death rate, a trend which is all the more striking given dramatically declining death rates from coronary artery disease, stroke and other cardiovascular disorders.
Fill Treatment Gap
While patients are visibly suffering, lacking the very basis for a decent quality of life – the ability to breathe – no pharmacologic therapy has demonstrated a reduction in the progressive loss of lung function that occurs, and the treatment options available to patients with COPD and other forms of lung disease are limited.
A substantial list of surgical interventions has been attempted in the past hundred years to help patients, particularly with emphysema. However, only two are effective, lung volume reduction surgery (LVRS) and lung transplantation, and neither is in widespread use or expected to be in the future.
The demand for interventional pulmonary therapies is huge, and these therapies are predicted to be the next area to succeed interventional cardiology.
