Pulmonary Valve Stenosis


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Pulmonary Valve Stenosis

 

Definition

Pulmonary valve stenosis is a congenital heart defect in which blood flow from the heart to the pulmonary artery is blocked.

Description

Pulmonary valve stenosis is an obstruction in the pulmonary valve, located between the right ventricle and the pulmonary artery. Normally, the pulmonary valve opens to let blood flow from the right ventricle to the lungs. When the pulmonary valve is malformed, it forces the right ventricle to pump harder to overcome the obstruction. In its most severe form, pulmonary valve stenosis can be life-threatening.
Patients with pulmonary valve stenosis are at increased risk for getting valve infections and must take antiobiotics to help prevent this before certain dental and surgical procedures. Pulmonary valve stenosis is also called pulmonary stenosis.

Causes and symptoms

Pulmonary valve stenosis is caused by a congenital malformation in which the pulmonary valve does not open properly. In most cases, scientists don't know why it occurs. In cases of mild or moderate stenosis, there are often no symptoms. With more severe obstruction, symptoms include a bluish skin tint and signs of heart failure.

Diagnosis

Diagnosis of pulmonary valve stenosis begins with the patient's medical history and a physical exam. Tests to confirm the diagnosis include chest x ray, echocardiogram, electrocardiogram, and catherization. An electrocardiograph shows the heart's activity. Electrodes covered with conducting jelly are placed on the patient. The electrodes send impulses that are traced on a recorder. Echocardiography uses sound waves to create an image of the heart's chambers and valves. The technician applies gel to a wand (transducer) and presses it against the patient's chest. The returning sound waves are converted into an image displayed on a monitor. Catherization is an invasive procedure used to diagnose, and in some cases treat, heart problems. A thin tube, called a catheter, is inserted into a blood vessel and threaded up into the heart, enabling physicians to see and sometimes correct the problems.

Treatment

Patients with mild to moderate pulmonary valve stenosis, and few or no symptoms, do not require treatment. In more severe cases, the blocked valve will be opened surgically, either through balloon valvuloplasty or surgical valvulotomy. For initial treatment, balloon valvuloplasty is the procedure of choice. This is a catherization procedure in which a special catheter containing a deflated balloon is inserted in a blood vessel and threaded up into the heart. The catheter is positioned in the narrowed heart valve and the balloon is inflated to stretch the valve open.
In some cases, surgical valvulotomy may be necessary. This is open heart surgery performed with a heart-lung machine. The valve is opened with an incision and in some cases, hypertrophied muscle in the right ventricle is removed. Rarely does the pulmonary valve need to be replaced.

Alternative treatment

Pulmonary valve stenosis can be life threatening and always requires a physician's care. In mild to moderate cases of pulmonary valve stenosis, general lifestyle changes, including dietary modifications, exercise, and stress reduction, can contribute to maintaining optimal wellness.

Prognosis

Patients with the most severe form of pulmonary valve stenosis may die in infancy. The prognosis for children with more severe stenosis who undergo balloon valvuloplasty or surgical valvulotomy is favorable. Patients with mild to moderate pulmonary stenosis can lead a normal life, but they require regular medical care.

Prevention

Pulmonary valve stenosis cannot be prevented.

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.
Children's Health Information Network. 1561 Clark Drive, Yardley, PA 19067. (215) 493-3068. http://www.tchin.org.
Congenital Heart Anomalies Support, Education & Resources, Inc. 2112 North Wilkins Road, Swanton, OH 43558. (419) 825-5575. 〈http://www.csun.edu/∼hfmth006/chaser〉.
Texas Heart Institute. Heart Information Service. P.O. Box 20345, Houston, TX 77225-0345. http://www.tmc.edu/thi.

Key terms

Congenital — Present at birth.
Pulmonary — Relating to the opening leading from the right large chamber of the heart into the lung artery.
Stenosis — A narrowing or constriction, in this case of various heart valves. Stenosis reduces or cuts off the flow of blood.
Valve — Tissue between the heart's upper and lower chambers that controls blood flow.

pulmonary

pertaining to the lungs, or to the pulmonary artery. See also lung.

pulmonary abscess
causes a syndrome of chronic toxemia, cough, loss of body weight. Careful auscultation may elicit squeaky rales around the lesions. See also caudal vena caval thrombosis, aspiration pneumonia.
pulmonary acinus
basic structural unit of the lung parenchyma; the gas exchange unit, supplied by a single terminal bronchiole and includes branches of the terminal bronchiole, alveolar ducts, alveolar sacs, alveoli and associated blood vessels. A pulmonary lobule consists of many acini.
pulmonary agenesis
incompatible with life; found only in fetal or neonatal necropsy specimens.
pulmonary alveolar microlithiasis
see microlithiasis alveolaris pulmonum.
pulmonary alveolar parenchyma
include epithelial cells (pneumonocytes or pneumocytes), alveolar capillary endothelial cells, and interstitial cells (fibroblasts) and alveolar macrophages.
pulmonary alveolar proteinosis
a disease of unknown etiology marked by chronic filling of the alveoli with a proteinaceous, lipid-rich, granular material consisting of surfactant and the debris of necrotic cells.
pulmonary arteriopathy
pulmonary artery wedge pressure
see wedge pressure.
pulmonary atelectasis
pulmonary bed
the network of capillaries in lung tissue.
pulmonary calcinosis
see microlithiasis alveolaris pulmonum.
pulmonary calculus
see bronchial calculus.
pulmonary carcinomatosis
see ovine pulmonary adenomatosis (below).
pulmonary circulation
the circulation of blood to and from the lungs. Deoxygenated blood from the right ventricle flows through the right and left pulmonary arteries to the right and left lung. After entering the lungs, the branches subdivide, finally emerging as capillaries which surround the alveoli and release the carbon dioxide in exchange for oxygen. The capillaries unite gradually and assume the characteristics of veins. These veins join to form the pulmonary veins, which return the oxygenated blood to the left atrium. See also circulatory system.
pulmonary compliance
a measure of the ability of the lung to distend in response to pressure without disruption. Expressed as the unit volume of change in the lung per unit of pressure. Compliance or distensibility of the lung is increased in conditions such as emphysema in which the lung distends more readily, and is decreased in fibrotic conditions in which the lung distends with difficulty. See also compliance.
pulmonary congestion
caused by engorgement of the pulmonary vascular bed and it may precede pulmonary edema when the intravascular fluid escapes into the parenchyma and the alveoli. There is a loss of air space and the development of respiratory embarrassment.
pulmonary cysts
may be congenital or acquired, caused by trauma, parasites (Paragonimus spp.), or associated with bronchiectasis. Rarely, metastatic tumors cavitate forming cysts.
pulmonary defense mechanisms
include aerodynamic filtration in nasal cavities, sneezing, local nasal antibody, laryngeal and cough reflexes, mucociliary transport mechanisms, alveolar macrophages, systemic and local antibody systems.
pulmonary edema
an effusion of serous fluid into the pulmonary interstitial tissues and alveoli. Preceded by pulmonary congestion (see above). If the extravascular exudation is sufficiently severe a critical level of hypoxia may be reached. The breathing will then be labored, the normal breath sounds on auscultation may be absent, and a frothy nasal discharge, often blood-tinged, may appear. At this stage the animal's life is about to terminate.
pulmonary embolus
obstruction of the pulmonary artery or one of its branches by an embolus. The embolus usually is a blood clot swept into circulation from a large peripheral vein.
Signs vary greatly, depending on the extent to which the lung is involved. Simple, uncomplicated embolism produces such cardiopulmonary signs as dyspnea, tachypnea, persistent cough, pleuritic pain and hemoptysis. On rare occasions the cardiopulmonary signs may be acute, occurring suddenly and quickly producing cyanosis and shock. A septic embolus can lead to local pulmonary abscess or an extension to pneumonia as in caudal vena caval syndrome. See also caudal vena caval thrombosis, pulmonary abscess (above).
pulmonary eosinophilic granulomatosis
a lesion common in heartworm disease; eosinophiles and neutrophils surround trapped microfilariae causing nodules as large as 3 inches diameter. May be preceded by lesions of allergic pneumonitis.
exercise-induced pulmonary hemorrhage
traces of blood can be found in about 60% of horses after racing. Less than 1% of these bleed from the nostrils. See also epistaxis.
pulmonary function tests
tests used to evaluate lung mechanics, gas exchange, pulmonary blood flow and blood acid-base balance. Pulmonary function testing is used to detect emphysema and chronic obstructive bronchitis at an early stage.
pulmonary hemorrhage
as distinct from hemothorax, is recognized because of a syndrome of dyspnea, increased lung density radiographically, and hemorrhagic anemia. If a large vessel ruptures into an abscess cavity there is usually a massive hemoptysis and instant death. Frothy blood-stained nasal discharge is an indication of pulmonary edema rather than of pulmonary hemorrhage. See also exercise-induced pulmonary hemorrhage (above).
pulmonary horse sickness
the predominantly pulmonary form of african horse sickness.
pulmonary hypertrophic osteoarthropathy
see hypertrophic osteopathy.
pulmonary hypoplasia
a congenital defect resulting in decreased lung development.
pulmonary infarction
see pulmonary infarction, pulmonary embolus (above).
pulmonary infiltration with eosinophilia (PIE)
pulmonary malformation
includes accessory lungs, pulmonary hypoplasia, pulmonary agenesis, congenital pulmonary cysts, endodermal heteroplasia, respiratory distress syndrome, neonatal maladjustment syndrome, immotile cilia syndrome.
pulmonary mycoses
includes aspergillosis, mortierellosis, blastomycosis, cryptococcosis, coccidioidomycosis.
pulmonary neoplasm
many types are recorded in all species but the prevalence is very low in food animals. A common site for metastases in companion animals. Characterized clinically by decreased exercise tolerance, progressive dyspnea, chronic cough and emaciation. Most diagnoses result from radiographic examination of the thorax for secondary growths.
neurogenic pulmonary edema
results from head trauma, central nervous system lesions and toxins, which may cause increased pulmonary blood pressure and alteration to sympathetic innervation leading to fluid leakage from vessels.
overriding pulmonary artery
see overriding pulmonary artery.
ovine pulmonary adenomatosis
a very chronic progressive pneumonia of sheep and goats caused by a retrovirus. Dyspnea, emaciation and a profuse nasal discharge are the cardinal signs, but coughing is not evident. The disease is always fatal. It is of great importance if it occurs in flocks that are housed for long periods. Characteristically the extensive lung involvement includes large areas of neoplastic tissue. Called also jaagsiekte, pulmonary carcinomatosis.
pulmonary patterns
see alveologram pattern, bronchial pattern.
re-expansion pulmonary edema
edema, emphysematous bullae and serosanguinous fluid in the airways with generalized pulmonary capillary endothelial damage; associated with chronic pulmonary collapse and removal of pleural effusions or pneumothorax with rapid re-expansion.
pulmonary rupture
traumatic, especially when there is rib fracture, or spontaneous due to coughing and a weak parenchyma. The most common cause of pneumothorax.
pulmonary thromboembolic disease
thromboembolism causing blockage of large sections of the pulmonary vascular bed will result in at least temporary severe dyspnea. It may also lead to right heart congestive failure, i.e. cor pulmonale.
pulmonary thrombosis
pulmonary valve
the pocket-like structure that guards the orifice between the right ventricle and the pulmonary artery.
pulmonary valve stenosis
causes right ventricular hypertrophy and a poststenotic dilatation of the pulmonary artery. There is a systolic murmur and thrill on the left side of the chest. A common congenital defect in dogs.
pulmonary vein
the large vein (right and left branches) that carries oxygenated blood from the lungs to the left atrium of the heart.
pulmonary wedge pressure
see wedge pressure.
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