Pulmonary Hypertension: A global health crisis we must address
Gerald Maarman is an associate professor in the division of medical physiology in the department of biomedical sciences at Stellenbosch University.
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Professor Gerald Maarman
World Pulmonary Hypertension Day is marked each year on 5 May to raise awareness of pulmonary hypertension (PH), a serious disease characterised by high blood pressure in the lungs. Without clinical intervention, this sustained pressure causes severe damage to the blood vessels, making it difficult for the heart to pump blood into the lungs.
Strain on the heart
Keep in mind that the right side of the heart normally pumps blood to the lungs, allowing the oxygen we breathe in to enter the blood and be circulated to the rest of the body. When PH is left untreated, the high blood pressure in the lungs places extra strain on the heart, causing right-sided heart failure. A patient with PH can develop heart failure quickly (within months), known as acute right heart failure, or over a longer period (within years). Pulmonary hypertension is associated with several conditions such as HIV, left heart disease (when the left side of the heart struggles to pump blood effectively), schistosomiasis (a disease caused by parasitic worms found in contaminated fresh water), congenital heart defects, chronic liver and kidney diseases, connective tissue diseases such as scleroderma (hardening and tightening of skin and other body parts) or lupus erythematosus (the immune system attacks healthy tissue throughout the body), chronic obstructive pulmonary disease (a chronic lung condition that limits airflow and causes breathing problems) and post-tuberculosis lung disease.
Prevalence of the disease
If a patient has any of these conditions, they have an increased risk of developing PH. Approximately 75 million people globally suffer from PH, and close to 80% of them are believed to live in developing countries, including South Africa. The prevalence of the disease in South Africa is not well documented, but previous studies have reported rates of around 14-19% for people with HIV and TB. Based on this logic, if, for example, eight million people in the country have these conditions, a PH prevalence of about 20% would suggest that about 1.6 million people may have PH.
This makes PH a dreadful disease, especially because it has no cure, and therefore, its potential burden on the healthcare system is a major concern. There are specialised medications to treat patients with PH, and combining these can extend life by up to 15 years. Patients who do not receive treatment may only live three to five years after a diagnosis. Unfortunately, PH medications are expensive and sadly not available in all countries. The reasons for the lack of access include exorbitant costs, limited funding, intellectual property rights, limited purchasing power, and infrastructure deficiencies. Some countries may have a proportion of the medications, while others may either have all or none.
The ethical question
This raises an important ethical question: If patients have PH and do not get access to medications because of their cost, are we truly comfortable with people dying, knowing full well something could have been done? The World Health Organization, the European Society of Cardiology, and the European Respiratory Society consider right-heart catheterisation (a procedure where a thin tube isused to measure pressure in the right side of the heart and lungs) as the gold standard for diagnosing PH. However, in many developing countries, this guideline cannot be used to diagnose patients because there is a lack of experienced cardiologists in rural areas, patients rarely access specialised cardiology centres where right-heart catheterisation could be performed, and the equipment is not always available. This means many people may have PH, but are never diagnosed and spend their lives in frustration and suffering due to inadequate clinical management.
Global collaboration
As an executive committee member of the Infections in Pulmonary Vascular Diseaseconsortium and a co-chairperson of a global research consortium commissioned by the American Thoracic Society, I collaborate with colleagues around the world to intensify efforts in diagnosing and treating PH. Over the last five years, a lot of work has been done to overcome the challenges regarding PH diagnosis and treatment. My own work has led to several recommendations to help mitigate challenges, including thedevelopment of better screening tools, engaging private funders, the investigation of new therapeutics or drug targets, the implementation of incentivised accredited training opportunities for clinicians and awareness campaigns.
Other recommendations include greater advocacy to encourage public and private funders to support research that brings together clinicians, natural and scientists, and implementation scientists. But we must go one step further in our fight against PH. We need to capitalise on the skills, social networks and experience of non-profit organisations to involve different stakeholders in combatting the disease. We must also implement breathlessness clinics in rural areas and conduct research into whether genetic changes or unique gene signatures could be used as disease markers.
*Maarman is an associate professor in the division of medical physiology in the department of biomedical sciences at Stellenbosch University. He specialises in cardiovascular and pulmonary physiology, focusing particularly on mitochondrialbioenergetics and metabolism in cardio-pulmonary diseases.