Pulmonary Hypertension (PH) is an umbrella term for elevation in the blood pressure of the lungs, now defined as a mean pulmonary arterial pressure ≥ 20mmHg. PH is broadly categorized into five sub-types: (1) pulmonary arterial hypertension (PAH) in which the pulmonary arteries develop obstructing lesions with normal lung tissue, (2) PH due to left heart disease in which high blood pressure in the left side of the heart is transmitted to the pulmonary vasculature, (3) PH due to lung disease and/or hypoxia in which the underlying lung disease, e.g. lung scarring, also reduces the number of blood vessels in the lung or causes thickening in the blood vessels, (4) PH due to chronic thromboemboli and (5) PH due to miscellaneous causes. Differentiation of these conditions requires chest and cardiac imaging, tests specifically for chronic thromboemboli, and right heart catheterization to confirm PH with the gold standard test and test for elevation in left heart filling pressures and severity of PH.
PAH is rare, with an estimated prevalence of 15-20/million population and primarily affects women with an average age of about 50 years. The last several decades have brought new understanding to how PAH develops and has even seen the development of specific medical therapies for this condition. While in the mid-1990s there was little to offer most patients other than supportive care, we now have four classes of medication for PAH, demonstrating the impressive research productivity in this disease and commitment on the part of patients and clinicians to high quality clinical drug trials in this disease. However, PAH remains deadly even today in many cases and most commonly affects young women, thus ongoing research is needed to bring a cure to this challenging, and rare, disease.
While surgical removal of chronic clot can often be curative in chronic thromboembolic PH and there is one medical therapy for this condition, there are no present FDA-approved therapies for PH due to lung disease or due to left heart disease. The molecular etiology of these conditions is not well understood and is an area of active research to help identify treatment targets to improve patient outcomes. Presently, when PH due to left heart or lung disease is recognized, it is recommended that patients improve or optimize therapy of these underlying conditions. PAH-directed therapies have generally not proven effective in these diverse conditions.
With an active community of clinicians, researchers and patients, we are optimistic about our ability to develop novel, more effective therapies for all forms of PH in the future. We appreciate your taking the time to read about this disease here and support ongoing efforts by the ATS to raise awareness of PH.
Four Facts About PH |
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