Pulmonary Hypertension

The term pulmonary hypertension refers to a group of conditions characterized by increased vascular resistance and therefore elevated blood pressure in the pulmonary circulation. The pulmonary circulation is the part of the circulatory system that carries blood from the heart to the lungs and back. Pulmonary hypertension often leads to right-sided heart failure the inability of the right ventricle to pump enough blood. Pulmonary hypertension can be classified as primary or secondary. This classification is a simplification.

Primary pulmonary hypertension is considered idiopathic: the cause of the disease cannot be determined. There is no known underlying disease mechanism (or it is not known), so the symptom itself pulmonary hypertension is regarded as the disease. This form of pulmonary hypertension is very rare. Various possible causes are discussed for example an increased release of vasoconstrictive factors or a reduced production of relaxing (vasodilating) factors. However, the cause is not sufficiently researched.

The secondary form of pulmonary hypertension is much more common. This occurs when pulmonary hypertension develops in the context of, or as a result of, an underlying condition. In this form it usually makes sense to treat the underlying disease in order to relieve or possibly cure the pulmonary hypertension. Common underlying conditions for secondary pulmonary hypertension include chronic obstructive pulmonary disease (COPD), pulmonary embolism, pulmonary fibrosis, sarcoidosis, AIDS, adult respiratory distress syndrome (ARDS), sickle cell anemia, scleroderma, or a congenital heart defect.

In the chronic form of pulmonary hypertension, the problem is not a short-term, activity-related narrowing of the lung vessels, but a remodeling of these vessels. The amount of vascular muscle increases and over time it is converted into connective tissue. The elasticity of the lung vessels decreases. The condition is irreversible. In addition, sclerosis (hardening) of the lung vessels occurs, which further worsens the situation. Lung ventilation no longer works optimally as the disease progresses. The ability to increase oxygen uptake during exertion is also lost. This leads to a progressive drop in oxygen uptake. The aforementioned heart failure develops as a result of the increased pulmonary arterial resistance: the hearts ability to pump blood gradually declines.

Patients with pulmonary hypertension have a greatly reduced physical capacity. A typical symptom is shortness of breath (dyspnea). Between 60 and 100 percent of patients experience shortness of breath with exertion. Cough and a generally reduced state of health are also typical symptoms. By reduced general condition we mean feeling generally unwell and physically weakened, which limits everyday activities. Other common symptoms and signs include circulatory problems up to fainting (syncope), chest pain (angina pectoris), fatigue, peripheral edema (swelling, usually in the legs), a bluish discoloration of the skin and/or mucous membranes (cyanosis), clubbing of the fingertips (digitus hippocraticus), and Raynauds phenomenon.

The mean pressure in the pulmonary artery (lung artery) is 12 to 16 mmHg in healthy people. Latent pulmonary hypertension is present at a pulmonary pressure of 21 to 24 mmHg at rest. Overt pulmonary hypertension is diagnosed when the pulmonary pressure at rest is above 25 mmHg. First symptoms are usually felt at a mean pulmonary artery pressure of about 30 to 40 mmHg. Symptoms then typically become worse with exertion. When pressures reach 50 to 70 mmHg, the hearts pumping ability steadily declines due to the increased pulmonary arterial resistance. Right heart strain increases. If untreated, this usually leads to right-sided heart failure and death from heart failure. Tricuspid valve insufficiency (regurgitation of the tricuspid valve) commonly occurs with pulmonary hypertension.

For diagnosis, a chest X-ray is usually taken. Echocardiography (ultrasound of the heart) can be used for an indirect estimate of pulmonary artery pressure, while a right heart catheterization measures the pulmonary artery pressure directly. A lung biopsy may be done if a secondary pulmonary hypertension is suspected. Laboratory tests can provide clues to an underlying or secondary heart failure.

Regarding treatment, any underlying condition should be treated to prevent pulmonary hypertension from becoming chronic. If chronic pulmonary hypertension develops, there is no curative therapy; treatment is then only palliative. Palliative treatment can be medical or, in some cases, surgical either a lung transplant or a combined heart-and-lung transplant. Drug therapy usually includes calcium channel blockers, prostacyclin derivatives (intravenous, subcutaneous, or inhaled), endothelin receptor antagonists, and PDE5 inhibitors. If the right heart is under strain, diuretics and digitalis preparations may also be indicated. Long-term oxygen therapy is often used to relieve symptoms and improve quality of life.

Pulmonary hypertension is divided into four stages. The prognosis is often poor. If untreated, average life expectancy from the time of diagnosis is less than three years. With a mean pulmonary artery pressure over 30 mmHg, the 5-year survival rate is about 30 percent. If the mean pulmonary artery pressure is over 50 mmHg, the 5-year survival rate is around 10 percent.

• https://www.netdoktor.de/krankheiten/pulmonale-hypertonie/
• https://flexikon.doccheck.com/de/Pulmonale_Hypertonie

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