Pulmonary vascular disease (PVD) includes a number of conditions that affect the blood vessels in the lungs of which the most common are pulmonary hypertension and pulmonary emboli. The most common causes of pulmonary hypertension are left heart disease, and certain advanced lung diseases, such as emphysema or lung fibrosis. A major focus of investigation for the last several decades, however, is pulmonary arterial hypertension (PAH) which is a rare disease that causes isolated pulmonary vascular thickening and commonly leads to right heart failure and death.
The first reported case of PAH occurred in 1891, when the German doctor E. Romberg published a description of a patient who, at autopsy, showed thickening of the pulmonary artery but no heart or lung disease that might have caused the condition. In 1951, 3 cases were reported by Dr. D.T. Dresdale in the U.S. and the illness was originally called primary pulmonary hypertension. PAH has been linked to diet drugs such as Fen-Phen, Pondimin and Redux. These drugs were taken off the market in 1997, although cases related to drugs and toxins, such as methamphetamines, do still appear. PAH is also associated with a number of other medical diseases such as cirrhosis and connective tissue diseases like scleroderma. About 30% of patients with PAH have an associated connective tissue disease. Patients with PAH are often breathless with daily activities and over time they can develop fluid retention and right heart failure, which is often the cause of death in this disease.
There have been major advances in understanding the origins of PAH, including discovery of several genes that can cause inherited types of PAH, and identification of abnormal “signaling” in several pathways. These discoveries have led to new medicines that extend the life of, and improves the exercise ability, of patients. However, there is still a lot more research needed to continue to improve the lives of patients with PAH.
A pulmonary embolism is a blood clot that travels, usually from the deep pelvic veins, to the lungs where it lodges and can cause difficulty breathing, chest pain and other symptoms. Pulmonary embolism is one of the most common PVD’s and is potentially fatal. The Centers for Disease Control and Prevention (CDC) reports as many as 900,000 people in the U.S. (1 to 2 per 1,000) can be affected by thromboembolic disease (diseases caused by clots in the veins or travel to the lungs). This number may be higher in patients who have by COVID-19. Fortunately, there are excellent treatment options to manage these diseases, including oral medicines that thin the blood (anticoagulants), and minimally invasive procedures, rather than major surgery, to remove the clots. There are still major challenges in managing pateints with thromboembolic disease, such as who clears the clots effectively, who develops long-lasting symptoms, who develops pulmonary hypertension, and when pulmonary embolism requires intervention to decrease the risk of long-term complications.
We are grateful for major research progress that has improved outcomes in both of these disease processes, yet we still have much to discover and there is room to further improve the life of patients affected with these diseases. The ATS, the Pulmonary Hypertension Association and the Scleroderma Foundation as well as the NIH/NHLBI and several other organizations have made major investments in research in PVD that is a major benefit to affected individuals and their loved ones and we continue to appreciate the benefits of this investment. ATS Pulmonary Vascular Disease Week provides an opportunity for us to increase knowledge and awareness of these important conditions.
