Pulmonary hypertension means high blood pressure in the lungs. This is an extremely important issue in scleroderma occurring in up to 40% of patients.
Patients with limited scleroderma have the risk of developing progressive blood vessel narrowing in the lungs frequently in the absence of lung scarring and inflammation. This complication is called pulmonary arterial hypertension (PAH). PAH can occur in diffuse scleroderma as well but a more common scenario is for progressive lung scarring to lead to loss of microvasculature in the lung again leading to elevated lung blood pressure. This syndrome is recognized by the WHO as pulmonary hypertension (PH) secondary to intrinsic lung disease.
In scleroderma, the left ventricle can become stiff or weakened, leading to back pressure into the lungs (red arrow). This is called heart failure. In patients with lung scarring (see Lung Involvement), the capillaries can be damaged (lavender arrow) which leads to PH. The distinctive problem in scleroderma is narrowing of the small lung arteries (blue arrow). This is the problem that leads to PAH.
As with many features of scleroderma, the basic issue is progressive scarring of the inner lining of the small artery. The changes in the lung blood vessels look remarkably similar to those in the fingers, kidneys and gastrointestinal tract. Many in the research community think of scleroderma as a blood vessel narrowing disease and view the immune system activation and tissue scarring as secondary events.
Injury to the endothelial cells which line healthy blood vessels leads to overproduction of endothelin – a key cause of blood vessel scarring and spasm – and to reduced production of nitric oxide and prostacyclins – two key body chemicals which keep blood vessels relaxed and open. Read More.......