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Hypertrophy of the medial layer of the pulmonary arteries occurs as a result of proliferation of pulmonary vascular smooth muscle cells. This increased muscularization can cause vascular obliteration and increased vascular resistance.1-3 Endothelin (ET) is known to have mitogenic effects on smooth muscle cells and may contribute to this process.1 Evidence of excess ET has been observed in pulmonary arteries with medial hypertrophy.4 |
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PULMONARY ARTERIAL HYPERTENSION (PAH) |
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Clinical Definition5,6 |
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Mean pulmonary arterial pressure >25
mm Hg at rest (>30 mm Hg with exercise) |
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Normal pulmonary capillary wedge pressure (PCWP) |
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Associated with arteriopathy and resultant
right ventricular strain |
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REFERENCES |
1. |
Miyauchi T, Masaki T. Pathophysiology of endothelin in the cardiovascular system. Annu Rev Physiol. 1999;61:391–415. |
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2. |
Dilworth JP, Baldwin DR. Respiratory Medicine. Amsterdam: Overseas Publishers Association, Harwood Academic; 2001:202–203. |
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3. |
McCance KL, Huether SE. Pathophysiology: The Biologic Basis for Disease in Adults and Children. 4th ed. St. Louis: Mosby; 2002:1133. |
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4. |
Giaid A, Yanagisawa M, Langleben D, et al. Expression of endothelin-1 in the lungs of patients with pulmonary hypertension. N Engl J Med. 1993;328:1732–1739. |
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5. |
Gaine SP, Rubin LJ. Primary pulmonary hypertension. Lancet. 1998;352:719–725. |
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6. |
Rubin LJ. Primary pulmonary hypertension. N Engl J Med. 1997;336:111–117. |
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© 2008 Actelion Pharmaceuticals US, Inc. All rights reserved. |
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