stenosis
(stĕ-nō'sĭs 
)
[Gr. stenōsis, a narrowing]
The constriction or narrowing of a passage or orifice.
SEE: obstruction (1).
stenosed, stenotic,
(stĕ-nōst )
(stĕ-nōzd' )
(stĕ-not'ik )
Causes: Stenosis may involve almost any tube or duct. It may result from embryonic maldevelopment, hypertrophy and thickening of a sphincter muscle, inflammatory disorders, or excessive development of fibrous tissue.
aortic s.Stenosis of blood flow from the left ventricle to the aorta due to aortic valve disease or obstructions just above or below the valve. About 2 percent of people with aortic sclerosis develop aortic stenosis annually.SYN: aortic valve stenosis aortostenosis.
Aortic stenosis is the most common cardiac valve dysfunction in the U.S. About 2% of people over the age of 65, 3% over age 75, and 4% over 85 have aortic stenosis. The incidence of aortic stenosis is increasing as the population of North America ages.
The stenosis may be congenital or secondary to diseases of adolescence or adulthood, e.g., rheumatic fever or fibrocalcific degeneration of the valve.
Many patients with mild or moderate aortic stenosis, e.g., with a valve area that is more than 1 cm2 or a valve gradient that is less than 50 mm Hg, have no symptoms and are unaware of their condition. A heart murmur is usually heard on physical examination of the patient. This murmur is best heard at the right second intercostal space during systole. Palpation of the arteries in severe aortic stenosis may reveal a delayed and weakened pulse, e.g., at the carotids. The heart's apical impulse may be laterally and inferiorly displaced as a result of left ventricular hypertrophy. Alarming symptoms include anginal chest pain, syncope, and exertional dyspnea. When these occur, surgery to repair or replace the diseased valve is necessary.
Transthoracic echocardiography diagnoses aortic stenosis and helps to evaluate its severity, determine left ventricular size and function, and detect other valvular disease.
Aortic stenosis and coronary artery disease share common risk factors (smoking, diabetes mellitus, hypertension, and high cholesterol levels). Lipoprotein (a) levels may also be an independent risk-enhancing factor.
If the aortic valve area is significantly narrowed, i.e., less than 0.8 cm2, or if the patient has experienced symptoms of heart failure or syncope, aortic valve replacement may be necessary.
A history of related cardiac disorders is obtained. Cardiopulmonary function is assessed regularly by monitoring vital signs and weight, intake, and output for signs of fluid overload. The patient is monitored for chest pain, which may indicate cardiac ischemia, and the electrocardiogram is evaluated for ischemic changes. Activity tolerance and fatigue are assessed.
After cardiac catheterization, the insertion site is checked according to protocol (often every 15 min for 6 hr) for signs of bleeding; the patient is assessed for chest pain, and vital signs, heart rhythm, and peripheral pulses distal to the insertion site are monitored. Problems are reported to the cardiologist.
Desired outcomes for all aortic valve surgeries include adequate cardiopulmonary tissue perfusion and cardiac output, reduced exertional fatigue, absence of excess fluid volume, and ability to manage the treatment regimen. Patients with aortic stenosis (with or without surgical repair) require prophylactic antibiotics before invasive procedures (including dental extractions and cleanings) because of the risk for bacteremia and infective endocarditis.
aortic valve s.Aortic stenosis
aqueductal s.Hydrocephalus resulting from a cerebrospinal fluid obstruction at the aqueduct of Sylvius.
cicatricial s.Stenosis due to a contracted scar.
coronary artery s.Stenosis of the flow of blood through the epicardial arteries, usually due to atherosclerotic plaque.
diaphyseal medullary s.Hardcastle syndrome.
infantile hypertrophic pyloric s.Pyloric stenosis.
lumbar spinal s.Stenosis of the spinal canal due to degenerative or traumatic changes at the level of the lumbar vertebrae. This condition causes back pain, often associated with pain that radiates into the legs, esp. when the patient is stand ing. Sitting often relieves the pain. The diagnosis is performed by spinal imaging, e.g., computed tomography or magnetic resonance imaging scanning. Treatments include physical therapy, braces, analgesic agents, and decompressive spinal surgery.
ABBR: MS
Stenosis of the mitral valve orifice with obstruction of blood flow from the left atrium to the left ventricle. In most adults, previous bouts of rheumatic carditis are responsible for the lesion. Less often, MS may be present at birth (Lutembacher disease), or it may develop as the mitral valve calcifies during aging.The abnormality of the valve may predispose patients to infective endocarditis; to left atrial enlargement and atrial arrhythmias; or to left ventricular failure.
pulmonary s.Stenosis of the opening into the pulmonary artery from the right cardiac ventricle.
pyloric s.Stenosis of the pyloric orifice, a cause of nausea, vomiting, dehydration, weight loss, and malnutrition in infancy.
It affects between 2 and 5 of every 1000 newborns and is more often present in boys than in girls.
Although the cause is not precisely known, it is thought to be due to both genetic and environmental influences.
Affected children typically begin to experience nausea and vomiting, often with great force and intensity (projectile vomiting), by about 1 month of age. Children who have previously been developing and growing normally may become dehydrated, and may lose weight.
The diagnosis may be suggested by palpating a firm round mass in the abdomen. Laboratory studies typically reveal low serum potassium and chloride levels. The diagnosis is confirmed with abdominal ultrasonography.
In infants excessive thickening of the pyloric sprinter or hypertrophy and hyperplasia of the mucosa and submucosa are identified on biopsy of affected lesions.
Pyloromyotomy effectively treats infants with the disease. In adults, endoscopic stents may be placed to open malignant obstructions.
SYN: infantile hypertrophic pyloric stenosis ; pyloristenosis.renal artery s.Stenosis in one or both arteries that supply the kidneys; a relatively uncommon cause of hypertension. In young women, the cause is usually fibromuscular dysplasia of one or both arteries. In older people, the cause is usually atherosclerosis.
Patients may be treated medically with stand ard antihypertensive drugs, or, in some cases, with renal artery angioplasty or bypass surgery.
SEE: illus.RENAL ARTERY STENOSIS.
subaortic s.A congenital stenosis of the aortic tract below the aortic valves.
SEE: hypertrophic cardiomyopathy .
symptomatic s.An arterial blockage that is responsible for angina, transient ischemia, or chronic ischemia.