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Pulmonary arterial hypertension
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Pulmonary arterial hypertension
Pulmonary arterial hypertension (PAH) is a syndrome in which the blood pressure in the pulmonary arteries and pulmonary arterioles (the blood vessels located proximal to the capillary bed, the site of oxygen exchange in the lungs) is elevated. This pre-capillary pulmonary artery pressure being elevated is essential, and by definition a mean pulmonary artery pressure greater than 20 mmHg as measured by a right heart catheterization is required for the diagnosis. This pre-capillary pulmonary hypertension is confirmed with measuring pulmonary vascular resistance being greater than 3 Woods Units. A pulmonary artery wedge pressure being less than 15 mmHg (also measured by right heart catheterization) excludes post-capillary bed (in the veins distal to the capillary bed) pulmonary hypertension. Pulmonary arterial hypertension is a subgroup of pulmonary hypertension and is categorized as World Health Organization as group 1. PAH is further subdivided into various categories based on the cause, including idiopathic, heritable, drug and toxin induced, PAH associated with specific diseases (such as connective tissue disorders, portal hypertension or HIV), PAH that is responsive to vasodilators, PAH with venous or capillary involvement, and persistent PAH in the newborn period.
If left untreated, the increased pulmonary vascular resistance will eventually lead to right heart failure and death. In the 1980s (before disease specific treatments became available) the 5 year survival rate was 34%. However, with more recent advances in disease specific therapies, survival in 2010 was 86%, 69%, and 61% at 1, 3 and 5 years respectively.
Signs and symptoms may be initially non-specific and may lead to a delay in appropriate diagnosis. Early symptoms include breathlessness (dyspnea). Other symptoms include fatigue, lightheadedness or fainting and chest pain. Late findings include swelling of the extremities, edema and ascites (which are signs of right heart failure).
Lower estimates regarding the prevalence of PAH are 15 cases per million adults with idiopathic PAH being 5.9 cases per million, with other estimates being 25 cases per 1 million people. In Europe, the prevalence ranges from 15-60 cases per year. More than half of PAH is believed to be idiopathic, drug induced or heritable.
Disease specific therapy involves targeting the various aberrant pathways involved in the disease. PDE5 inhibitors are used which cause dilation of blood vessels. Riociguat also causes vasodilation. Endothelin receptor antagonists cause vasodilation as well by blocking the action of the potent vasoconstrictor endothelin-1. Prostacyclins and prostacyclin agonists also cause vasodilation and also inhibit platelet aggregation. In disease that is refractory to medical therapy, an atrial septostomy may be used palliatively or as a bridge to lung transplantation.
Dyspnea (breathlessness) is the most common symptom associated with PAH and also usually the first symptom, with 98% of people experiencing dyspnea at the time of diagnosis. Fatigue, lightheadedness, palpitations, chest pain are also present. Late findings include near-syncope or syncope (fainting). As PAH progresses and chronically elevated pulmonary arterial pressures result in right heart failure; swelling of the legs and other areas of the body (edema), fluid buildup in the abdomen (ascites) develop as late symptoms.
Findings on physical exam indicating right heart failure may be present, including a loud P2 heart sound (the sound from the pulmonic valve closing), a heart murmur indicating tricuspid regurgitation or an elevated jugular venous pressure.
The WHO introduced a functional classification in PAH which is used to estimate disease severity as well as response to treatment. WHO class 1 is characterized by no limitations with usual physical activity. Class 2 involves discomfort with physical activity and mild limitations. Class 3 disease involves a marked limitation with physical activity and symptoms being present with light activities. Class 4 disease involves severe symptoms with almost any physical activity and symptoms being present at rest.
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Pulmonary arterial hypertension
Pulmonary arterial hypertension (PAH) is a syndrome in which the blood pressure in the pulmonary arteries and pulmonary arterioles (the blood vessels located proximal to the capillary bed, the site of oxygen exchange in the lungs) is elevated. This pre-capillary pulmonary artery pressure being elevated is essential, and by definition a mean pulmonary artery pressure greater than 20 mmHg as measured by a right heart catheterization is required for the diagnosis. This pre-capillary pulmonary hypertension is confirmed with measuring pulmonary vascular resistance being greater than 3 Woods Units. A pulmonary artery wedge pressure being less than 15 mmHg (also measured by right heart catheterization) excludes post-capillary bed (in the veins distal to the capillary bed) pulmonary hypertension. Pulmonary arterial hypertension is a subgroup of pulmonary hypertension and is categorized as World Health Organization as group 1. PAH is further subdivided into various categories based on the cause, including idiopathic, heritable, drug and toxin induced, PAH associated with specific diseases (such as connective tissue disorders, portal hypertension or HIV), PAH that is responsive to vasodilators, PAH with venous or capillary involvement, and persistent PAH in the newborn period.
If left untreated, the increased pulmonary vascular resistance will eventually lead to right heart failure and death. In the 1980s (before disease specific treatments became available) the 5 year survival rate was 34%. However, with more recent advances in disease specific therapies, survival in 2010 was 86%, 69%, and 61% at 1, 3 and 5 years respectively.
Signs and symptoms may be initially non-specific and may lead to a delay in appropriate diagnosis. Early symptoms include breathlessness (dyspnea). Other symptoms include fatigue, lightheadedness or fainting and chest pain. Late findings include swelling of the extremities, edema and ascites (which are signs of right heart failure).
Lower estimates regarding the prevalence of PAH are 15 cases per million adults with idiopathic PAH being 5.9 cases per million, with other estimates being 25 cases per 1 million people. In Europe, the prevalence ranges from 15-60 cases per year. More than half of PAH is believed to be idiopathic, drug induced or heritable.
Disease specific therapy involves targeting the various aberrant pathways involved in the disease. PDE5 inhibitors are used which cause dilation of blood vessels. Riociguat also causes vasodilation. Endothelin receptor antagonists cause vasodilation as well by blocking the action of the potent vasoconstrictor endothelin-1. Prostacyclins and prostacyclin agonists also cause vasodilation and also inhibit platelet aggregation. In disease that is refractory to medical therapy, an atrial septostomy may be used palliatively or as a bridge to lung transplantation.
Dyspnea (breathlessness) is the most common symptom associated with PAH and also usually the first symptom, with 98% of people experiencing dyspnea at the time of diagnosis. Fatigue, lightheadedness, palpitations, chest pain are also present. Late findings include near-syncope or syncope (fainting). As PAH progresses and chronically elevated pulmonary arterial pressures result in right heart failure; swelling of the legs and other areas of the body (edema), fluid buildup in the abdomen (ascites) develop as late symptoms.
Findings on physical exam indicating right heart failure may be present, including a loud P2 heart sound (the sound from the pulmonic valve closing), a heart murmur indicating tricuspid regurgitation or an elevated jugular venous pressure.
The WHO introduced a functional classification in PAH which is used to estimate disease severity as well as response to treatment. WHO class 1 is characterized by no limitations with usual physical activity. Class 2 involves discomfort with physical activity and mild limitations. Class 3 disease involves a marked limitation with physical activity and symptoms being present with light activities. Class 4 disease involves severe symptoms with almost any physical activity and symptoms being present at rest.
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