A
ACE inhibitors
Drugs that lower blood pressure by preventing the formation of angiotensin II, a hormone that causes arteries to constrict and that triggers the release of the hormone aldosterone. Also used to slow the progression of kidney disease.
aldosterone
A hormone released by the adrenal glands that increases blood pressure by signaling the kidneys to retain sodium, which increases blood volume.
aldosterone blockers
Drugs that lower blood pressure by interfering with the activity of the hormone aldosterone.
aldosteronism
An overproduction of aldosterone caused by a tumor or overgrowth of cells in the adrenal gland. Aldosteronism can lead to hypertension.
alpha-blockers
Drugs that decrease blood pressure by blocking nerve impulses that constrict small arteries.
ambulatory blood pressure monitor
A portable device that automatically measures and records blood pressure over a 24- to 48-hour period. Measurements are taken while you go about daily activities as well as during sleep.
aneroid blood pressure monitor
A manually operated monitor that consists of a cuff, bulb, and dial gauge to register blood pressure levels.
aneurysm
A ballooning of the wall of a blood vessel caused by weakening of the wall.
angina
Episodes of chest pain caused by an inadequate supply of oxygen and blood to the heart. It occurs most often during physical activity.
angioplasty
A procedure in which a small balloon is inflated in a blocked artery to enlarge the path for blood flow.
angiotensin
A hormone that has two forms: angiotensin I and angiotensin II. The latter raises blood pressure by causing arteries to constrict and triggering the release of aldosterone.
angiotensin II receptor blockers
Drugs that help lower blood pressure by interfering with the action of angiotensin II.
anticoagulants
Anticlotting drugs that work by inhibiting the formation of fibrin, a protein required for blood clot formation. Examples are heparin and warfarin (Coumadin).
antiplatelets
Anticlotting drugs that work by inhibiting the clumping of blood cells called platelets. One example is aspirin.
aphasia
Difficulty in comprehending or producing spoken or written language. Results from damage to the frontal lobe, temporal lobe, or limbic system.
arteriovenous malformation
A disorder present at birth and characterized by a complex, tangled web of arteries and veins.
aspiration pneumonia
Pneumonia caused by the inhalation of food and other particles into the lungs.
atherosclerosis
The narrowing of arteries by fatty deposits (called plaques) within the artery walls that can cause a reduction in blood flow.
atrial fibrillation
A common abnormal heart rhythm in which the atria (the upper chambers of the heart) quiver chaotically instead of contracting in a rhythmic pattern.
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B
baroreceptors
Special nerve endings in the walls of arteries that monitor blood pressure.
basilar arteries
Arteries that provide branches to sections of the brain (cerebrum, cerebellum) often involved in strokes. The basilar artery is the major artery feeding the brain stem.
beta-blockers
Drugs that slow the heart rate and lower blood pressure by diminishing the amount of blood pumped by the heart.
b-mode imaging
An imaging technique that uses highfrequency sound waves to produce a three-dimensional view of the carotid arteries.
brain stem
An area located at the base of the brain above the spinal cord that maintains basic life support functions such as breathing, heart rate, and blood pressure.
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C
calcium channel blockers
Drugs that lower blood pressure by dilating arteries and, in some cases, by decreasing the amount of blood pumped by the heart.
cardiac output
The amount of blood pumped by the heart.
cardiovascular disease
Disease affecting the arteries that supply blood to the heart and other organs. Coronary heart disease, stroke, and peripheral arterial disease are the most common cardiovascular diseases.
carotid arteries
Blood vessels that carry oxygen- and nutrient-rich blood from the heart to the brain. There are two carotid arteries
one on each side of the front of the neck.
carotid endarterectomy
A surgical procedure to remove plaque from the carotid arteries.
carotid stenosis
A narrowing of the carotid arteries by plaque.
central alpha agonists
Drugs that lower blood pressure by blocking nerve impulses that constrict small arteries.
cerebellum
The area of the brain located above the brain stem that controls coordination, balance, and posture.
cerebral angiography
A procedure involving the injection of an iodine-based contrast solution into the bloodstream to produce high-quality x-ray images of the blood vessels within the brain.
cerebral edema
Swelling of the brain due to bleeding, trauma, a stroke, or a tumor.
cerebrum
The largest portion of the brain. It controls conscious thought, perception, voluntary movement, and integration of sensory input.
combination therapy
A treatment approach that uses medication from two or more drug classes.
computed tomography (CT) scan
A test in which a patient lies flat on a table while x-rays are passed through the body and sensed by a rotating detector. A CT scan of the head can reveal strokes.
coronary heart disease
A narrowing of the coronary arteries by the buildup of fatty deposits called plaques. Reduces or completely blocks blood flow to the heart.
c-reactive protein (CRP)
A marker of inflammation produced by the liver. High levels indicate an increased risk of a stroke.
Cushing’s syndrome
A condition resulting from the secretion of excessive amounts of cortisone and related hormones by a tumor in the adrenal gland. A potential cause of high blood pressure.
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D
DASH diet
This diet (Dietary Approaches to Stop Hypertension) is high in fruits, vegetables, and low-fat dairy products and, in some people, can lower blood pressure as much as taking a single blood pressure drug.
deep vein thrombosis
The formation of a blood clot in the legs.
diabetes
A disorder characterized by abnormally high levels of glucose (sugar) in the blood.
diastolic blood pressure
The lower number in a blood pressure reading. Represents pressure in the arteries when the heart relaxes between beats.
direct vasodilators
Antihypertensive drugs that act directly on the smooth muscle of small arteries, causing these arteries to expand (dilate).
diuretics
A class of experimental drugs that increases loss of sodium through the kidneys, thereby increasing the production of urine and decreasing blood volume and blood pressure.
Doppler ultrasound
The use of sound waves to measure how fast blood moves through arteries, such as the carotid arteries.
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E
electronic blood pressure monitor
A battery-operated blood pressure monitor that uses a microphone to detect blood pulses in an artery. Consists of an inflatable cuff and a gauge with a digital screen.
embolic stroke
A blockage of blood flow to the brain that occurs when part of a blood clot or a piece of atherosclerotic plaque breaks off and travels through the bloodstream until it lodges in an artery supplying blood to the brain.
embolus
A blood clot or a piece of plaque that comes loose and travels through the bloodstream until it lodges in a narrowed vessel and blocks blood flow. The plural form is emboli.
epinephrine
A hormone that increases blood pressure in response to stress. Also called adrenaline.
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F
frontal lobe
An area at the front of the brain that deals with speech and motor function.
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G
glomeruli
Sites in the kidneys where blood is filtered and waste products are removed.
glutamate cascade
See ischemic cascade.
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H
hematoma
A mass of clotted blood that forms as a result of a ruptured blood vessel.
hemorrhagic stroke
A stroke that occurs when an artery in the brain suddenly tears or bursts and blood leaks into the surrounding tissue.
high-density lipoprotein (HDL)
A particle in the blood that can protect against coronary heart disease by removing cholesterol from the body.
hypertension
High blood pressure. Diagnosed when at least two blood pressure readings on separate occasions are 140/90 mm Hg or higher.
hypertensive crisis
A condition characterized by extremely high blood pressure levels (diastolic blood pressure above 120 mm Hg). Occurs in about 1% of people with hypertension.
hypotension
Low blood pressure. Can cause dizziness or lightheadedness.
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I
intracerebral hemorrhage
Leakage of blood from a damaged blood vessel into tissues deep within the brain.
ischemia
A lack of oxygen due to a decrease in blood supply to an organ or tissue.
ischemic cascade
A chain of chemical reactions, occurring during an ischemic stroke, that leads to a buildup of toxins and further cell destruction. Also called glutamate cascade.
ischemic stroke
A stroke resulting from the blockage of an artery supplying blood to the brain.
isolated systolic hypertension
A systolic blood pressure of 140 mm Hg or higher along with a diastolic blood pressure under 90 mm Hg. Associated with an increased risk of stroke, coronary heart disease, and kidney disease.
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J
J-curve phenomenon
Refers to the relationship between the risk of a heart attack and blood pressure. The curve shows that those with the highest and lowest blood pressure levels are more likely to die of a heart attack than those with an intermediate blood pressure level. Many experts question whether the J-curve phenomenon exists.
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K
kidneys
A pair of organs, located on the left and right sides of the abdomen, that remove waste products and excess water from the blood and produce urine.
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L
left ventricular hypertrophy
A thickening of the muscular wall of the left ventricle that occurs when the heart must work harder to pump blood. Common in people with hypertension.
limb contracture
Consistent tightening of muscles or surrounding ligaments and tendons in the limbs.
limbic system
A group of structures in the brain responsible for basic urges and powerful emotions--for example, hunger and terror--that help ensure self-preservation.
low-density lipoprotein (LDL)
A particle that transports cholesterol in the bloodstream and is a major contributor to coronary heart disease. Its deposition in artery walls initiates plaque formation.
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M
magnetic resonance angiography (MRA)
A technique for producing two- and three-dimensional images of blood clots and aneurysms as well as narrowed or blocked carotid arteries. Similar to an MRI but uses special computer software to generate images of the blood vessels.
magnetic resonance imaging (MRI)
A test that employs magnetic fields and radio waves to generate a three-dimensional image of a part of the body, such as the brain.
Merci retriever
A device for treating strokes that consists of a corkscrew-shaped wire, which traps and removes blood clots within the brain to restore blood flow.
metabolic syndrome
A group of characteristics, including obesity, hypertension, high triglyceride levels, low HDL cholesterol levels, and elevated blood glucose levels, that nearly doubles the risk of having a stroke.
motor cortex
A part of the frontal lobe of the brain. >Damage to this area can result in weakness or paralysis on the opposite side of the body.
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N
neuron
Nerve cell.
nitric oxide
A substance secreted by cells lining the walls of blood vessels that causes arteries to dilate by relaxing smooth muscle cells.
norepinephrine
A hormone that increases blood pressure in response to stress.
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O
occipital lobe
An area of the brain at the back of the skull that is dedicated to the perception and interpretation of visual data from the eyes.
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P
parietal lobe
An area of the brain behind the frontal lobe that receives and interprets sensory signals from all parts of the body.
peripheral-acting adrenergic antagonists
Drugs that reduce resistance to blood flow in small arteries.
peripheral arterial disease
A narrowing of the arteries in the extremities, usually the legs. Most often due to the buildup of fatty deposits called plaques.
pheochromocytoma
A tumor in the adrenal gland that secretes large amounts of epinephrine or norepinephrine. Can lead to hypertension.
plaque
An accumulation of cholesterol, smooth muscle cells, fibrous proteins, and calcium in artery walls that narrows the arteries and reduces blood flow.
potassium
A mineral found mainly in fruits and vegetables. Increased intake helps lower blood pressure.
prehypertension
A term used to describe people with systolic blood pressure between 120 and 139 mm Hg or diastolic blood pressure between 80 and 89 mm Hg. These individuals are at high risk for hypertension.
primary hypertension
Hypertension related to poor diet, excess weight, high salt intake, or physical inactivity. Affects 90–95% of people with hypertension.
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Q
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R
renin
A hormone produced by cells in the kidney that initiates a chain of events that causes blood pressure to rise.
renovascular hypertension
A type of hypertension caused by a reduction in blood flow to the kidneys.
retinopathy
Damage to the retina of the eye caused by changes in the tiny blood vessels that supply the retina.
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S
salt
Another term for sodium chloride. One teaspoon of salt contains 2,400 mg of sodium.
secondary hypertension
Hypertension caused by another health condition or a medication. Responsible for less than 5% of cases of hypertension.
sodium
A mineral found mostly in processed foods, including salted snacks, canned soups, luncheon meats, and frozen dinners. In general, diets high in sodium cause blood pressure to rise.
sphygmomanometer
An instrument used to measure blood pressure. Consists of an inflatable cuff that can be filled with air, an inflating bulb that pumps air into the cuff, and a gauge that contains a column of mercury.
stent
A wire mesh screen that is inserted into an artery to help keep it open.
stroke
A sudden reduction in or loss of brain function that occurs when an artery supplying blood to a portion of the brain becomes blocked or ruptures. Neurons in the affected area are starved of the oxygen and nutrients they need to function properly.
subarachnoid hemorrhage
Leakage of blood into the space between the brain and the arachnoid membrane, the middle of three membranes that envelop the brain. Most commonly results from trauma or a ruptured aneurysm.
systolic blood pressure
The upper number in a blood pressure reading. Represents pressure in the arteries when the heart is pumping blood to the rest of the body.
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T
temporal lobe
An area of the brain at ear level underneath the parietal and frontal lobes that is responsible for hearing and storage of memories.
thrombolytic drugs
Medications that dissolve blood clots.
thrombotic stroke
A blockage of blood flow that occurs when a blood clot forms at the site of plaque within the wall of a major artery supplying the brain. The most common type of ischemic stroke.
thrombus
A blood clot. The plural form is thrombi.
tissue-type plasminogen activator (t-PA)
A drug used to treat heart attacks and strokes that works by dissolving blood clots. Also called alteplase (Activase).
transient ischemic attack (TIA)
Short-lived and reversible symptoms of a stroke that are caused by a temporary reduction in blood flow to the brain. Most episodes subside within five to 20 minutes.
triglyceride
A lipid (fat) in the bloodstream. Elevated levels are associated with an increased risk of coronary heart disease.
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U
ultrasound scanning
The use of high-frequency sound waves to create two-dimensional images that can pinpoint the site of a blockage in an artery that is causing an ischemic stroke.
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V
vertebral arteries
Blood vessels that run up the back of the neck, parallel to the spine, and carry blood to the brain stem and rear third of the brain.
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W
white coat hypertension
High blood pressure readings that are present only when blood pressure is measured by a physician or in a medical environment. Blood pressure is normal when taken at home by the patient or by a family member or friend.
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X
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Y
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Z
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Derived from The Johns Hopkins White Paper 2007: Hypertension and Stroke
Look In the Book: Hypertension and Stroke White Paper
copyright 2007 Johns Hopkins Health Alerts.
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