Vasoactivity

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A vasoactive substance is an endogenous agent or pharmaceutical drug that has the effect of either increasing or decreasing blood pressure and/or heart rate through its vasoactivity, that is, vascular activity (effect on blood vessels). By adjusting vascular compliance and vascular resistance, typically through vasodilation and vasoconstriction, it helps the body's homeostatic mechanisms (such as the renin–angiotensin system) to keep hemodynamics under control. For example, angiotensin, bradykinin, histamine, nitric oxide, and vasoactive intestinal peptide are important endogenous vasoactive substances. Vasoactive drug therapy is typically used when a patient has the blood pressure and heart rate monitored constantly. The dosage is typically titrated (adjusted up or down) to achieve a desired effect or range of values as determined by competent clinicians.

Vasoactive drugs are typically administered using a volumetric infusion device (IV pump). This category of drugs require close observation of the patient with near immediate intervention required by the clinicians in charge of the patient's care. Important vasoactive substances are angiotensin-11, endothelin-1, and alpha-adrenergic agonists.

Various vasoactive agents, such as prostanoids, phosphodiesterase inhibitors, and endothelin antagonists, are approved for the treatment of pulmonary arterial hypertension. The use of vasoactive agents for patients with pulmonary hypertension may cause harm and unnecessary expense to persons with left heart disease or hypoxemic types of lung diseases. [1]

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Blood pressure Pressure exerted by circulating blood upon the walls of blood vessels

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Vasodilation

Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, which is the narrowing of blood vessels.

Pulse pressure is the difference between systolic and diastolic blood pressure.

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Amlodipine

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Pulmonary hypertension Condition causing increased blood pressure within the arteries of the lungs

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Haemodynamic response

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Cardiac catheterization

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Sitaxentan

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Endothelin

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Bosentan

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Iloprost

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Right ventricular hypertrophy

Right ventricular hypertrophy (RVH) is a condition defined by an abnormal enlargement of the cardiac muscle surrounding the right ventricle. The right ventricle is one of the four chambers of the heart. It is located towards the lower-end of the heart and it receives blood from the right atrium and pumps blood into the lungs.

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Pathophysiology of hypertension

Pathophysiology is a branch of medicine which explains the function of the body as it relates to diseases and conditions. The pathophysiology of hypertension is an area which attempts to explain mechanistically the causes of hypertension, which is a chronic disease characterized by elevation of blood pressure. Hypertension can be classified by cause as either essential or secondary. About 90–95% of hypertension is essential hypertension. Some authorities define essential hypertension as that which has no known explanation, while others define its cause as being due to overconsumption of sodium and underconsumption of potassium. Secondary hypertension indicates that the hypertension is a result of a specific underlying condition with a well-known mechanism, such as chronic kidney disease, narrowing of the aorta or kidney arteries, or endocrine disorders such as excess aldosterone, cortisol, or catecholamines. Persistent hypertension is a major risk factor for hypertensive heart disease, coronary artery disease, stroke, aortic aneurysm, peripheral artery disease, and chronic kidney disease.

References

  1. American College of Chest Physicians; American Thoracic Society (September 2013), "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation , American College of Chest Physicians and American Thoracic Society, retrieved 6 January 2013