Aortic Valve Stenosis
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Aortic Valve Stenosis
Cause and symptoms
aortic valve stenosisAortic stenosis, see there.
Aortic Valve Stenosis
|Mean LOS:||3.3 days|
|Description:||MEDICAL: Cardiac Congenital and Valvular Disorders without Major CC|
Aortic stenosis (AS) is a narrowing of the aortic valve orifice, which obstructs outflow from the left ventricle during systole. The left ventricle must overcome the increased resistance to ejection by generating a higher-than-normal pressure during systole, which is achieved by stretching and generating a more forceful contraction. The blood is propelled through the narrowed aortic valve at an increased velocity. Aortic valve stenosis accounts for approximately 5% of all congenital heart defects. About 4 in 1,000 live births have AS, making this condition a relatively common birth defect.
As the stenosis in the aortic valve progresses, two sequelae occur. One is that cardiac output becomes fixed, making increases even with exertion impossible. The other is left-sided heart failure. Pressure overload of the heart occurs with concentric hypertrophy of the left ventricle. Left ventricular end-diastolic pressure rises, myocardial oxygen demand increases, and left ventricular mass and wall stress are increased. The increase in left ventricular pressure is reflected backward into the left atrium. Because the left atrium is unable to empty adequately, the pulmonary circulation becomes congested. Eventually, right-sided heart failure can develop as well.
The predominant causative factor in AS is congenital malformation of the aortic valve. Congenital causes can lead to unicuspid and bicuspid or malformed valves. When they become calcified, symptoms may occur. Stenosis can also occur with narrowing of the subvalvular outflow tract by fibroelastic membranes or muscle tissue. Acquired valvular stenosis results from rheumatic heart disease and degenerative calcification. Risk factors for degenerative stenosis include hypertension, elevated cholesterol, diabetes mellitus, and smoking. The patient’s age when the condition manifests itself usually suggests the cause. Congenital stenosis is usually seen in patients younger than 30 years old. In patients between the ages of 30 and 70 years, the cause is equally attributed to congenital malformation and rheumatic heart disease. Atherosclerosis and degenerative calcification of the aortic valve are the predominant causes for stenosis in people older than 70 years.
There is considerable evidence supporting a genetic component for congenital AS. Bicuspid aortic valve, which can result in AS, is often found among relatives of persons affected with other left ventricular outflow tract malformations. AS occurs as a feature of rare genetic diseases such as Williams syndrome, which has autosomal dominant transmission, characteristic facial features, and mental retardation. Mutations in the NOTCH1 gene can lead to aortic valve calcification, among other congenital aortic valve defects, in an autosomal dominant inheritance pattern.
Gender, ethnic/racial, and life span considerations
AS can occur at any age, depending on the cause. Among children born with AS, 75% are male, and overall approximately 80% with AS are male. Degenerative aortic stenosis is most common in males older age 75. Ethnicity and race have no known effect on the risk of AS.
Global health considerations
Rheumatic heart disease and subsequent valvular disease is a continuing problem in developing nations, where up to 60% of all admissions for cardiovascular illnesses are related to the condition. Prevalence may be as low as 1 per 100,000 children in Costa Rica to as high as 150 per 100,000 children in China. Areas of particular concern are Southeastern Asia, Central America, North Africa, and the Middle East.
A history of rheumatic fever suggests possible cardiac valvular malfunction; however, many patients who have had rheumatic fever do not remember having had the condition. The diagnosis therefore is usually based on symptoms. Given the potential genetic causes, a family history of AS can be significant.
The classic symptoms of aortic stenosis are chest pain, fainting on exertion (syncope), and labored breathing on exertion due to heart failure. Inspection of the thoracic wall may reveal a thrusting apical pulsation. A systolic thrill (vibrations felt from turbulent blood flow) may be palpated over the second intercostal space to the right of the sternum. A lift or heave may be palpated over the apex of the heart.
Auscultation of heart sounds reveals a harsh systolic crescendo-decrescendo murmur. The murmur, referred to as diamond shaped, is considered the hallmark of AS. Auscultation of breath sounds may reveal fine crackles (rales) if pulmonary congestion is present in left-sided heart failure. The pulmonary congestion will vary with the amount of exertion and severity of stenosis.
Because the symptoms of AS are usually gradual, most people have already made adjustments in their lifestyle to adapt and do not seek treatment until the symptoms become debilitating. Assess what the patient has already done to cope with this condition. In addition, assess the patient’s degree of anxiety about a diagnosed heart condition and potential treatment.
|Test||Normal Result||Abnormality With Condition||Explanation|
|Cardiac catheterization||Normal aortic valve||Opening in the aortic valve is obstructed and narrowed||Aortic valve is narrowed with the pressure gradient across the valve directly related to the degree of obstruction|
|Two-dimensional and Doppler echocardiography||Normal aortic valve||Stenosed aortic valve||Reveals abnormal blood flow patterns|
Other Tests: Echocardiography to assess the aortic valve’s structure and mobility; electrocardiogram; chest radiography, radionuclide ventriculography, computed tomography, magnetic resonance imaging
Primary nursing diagnosis
DiagnosisActivity intolerance related to imbalance between oxygen supply and demand
OutcomesEndurance; Energy conservation; Self-care; Ambulation: Walking; Circulation status; Cardiac pump effectiveness; Rest; Respiratory status; Symptom severity; Nutritional status: Energy
InterventionsActivity therapy; Energy management; Circulatory care; Exercise therapy: Ambulation; Oxygen therapy; Self-care assistance; Nutrition management
Planning and implementation
medical.Most patients with AS are placed on activity restrictions to decrease cardiac workload. Patients on bedrest should use the bedside commode because research has shown it creates less workload for the heart than using the bedpan. Fluid restrictions and diuretics may be ordered to reduce pulmonary congestion. Supplemental oxygenation will enhance oxygen levels in the blood to decrease labored breathing and chest pain. Percutaneous balloon valvuloplasty is used as a palliative measure in people who are not surgical candidates or as a bridge in the critically ill before they undergo aortic valve replacement.
surgical.Surgical repair or replacement is the most common treatment of AS. The average survival rate after the appearance of symptoms is less than 5 years for patients with AS who are treated medically. Surgical treatment increases the survival rate dramatically. The stenotic valve can be replaced with a synthetic valve or a biologic valve, such as a pig valve. The choice of valve type is based on the patient’s age and the potential for clotting problems. The biologic valve usually shows structural deterioration after 6 to 10 years and needs to be replaced. The synthetic valve is more durable but also more prone to thrombi formation. For patients who are not candidates for aortic valve replacement, percutaneous aortic balloon valvuloplasty may reduce some symptoms.
|Medication or Drug Class||Dosage||Description||Rationale|
|Digoxin||0.25 mg PO qd||Cardiotonic||May be useful in the presence of heart failure and left ventricular dilation and impaired systolic function|
|Beta-adrenergic receptor blockers (esmolol, metoprolol)||Varies with drug||Beta-adrenergic receptor blocker||Used to manage angina or elevated blood pressure in patients who are not candidates for surgery or prior to surgery|
Other Therapy: Diuretics, nitrates, and other vasodilators are to be avoided if possible because they reduce filling pressures and may lower systolic blood pressure. If the stenotic valve is replaced surgically with a synthetic valve, patients are prescribed long-term anticoagulation therapy, such as warfarin (Coumadin), to prevent thrombi from forming on the synthetic valve. Initially, heparin is given along with the warfarin, and the prothrombin time (PT) is monitored. As the PT value becomes therapeutic, the heparin is discontinued.
Physical and psychological rest decreases cardiac workload, which reduces the metabolic demands of the myocardium. Physical rest is enhanced by providing assistance with activities of daily living and encouraging activity restrictions. Reducing psychological stress can also be difficult. Decrease the fear of the unknown by providing explanations and current information and encouraging questions. To help the patient maintain or reestablish a sense of control, permit the patient to participate in decisions about aspects of care within his or her knowledge. If the patient decides on surgery, offer to let her or him speak with someone who has already had the surgery.
Discourage sudden changes in position to minimize increased cardiac demand. Instruct the patient to sit on the edge of the bed before standing. Elevate the head of the bed slightly if pulmonary congestion is present, to enhance respiration.
Monitoring physical status is a priority for nursing care. Assess for episodes of dizziness or fainting. The episodes may occur because of decreased cardiac output or cardiac dysrhythmias, so patients should be told to report occurrence of these symptoms promptly. Dizziness and fainting are correlated with sudden death, which, according to recent research, occurs in 10% to 20% of all patients with advanced AS. Maintain a safe physical environment for the patient by removing obstructions in the patient’s room.
Evidence-Based Practice and Health Policy
Zlotnick, D.M., Ouellette, M.L., Malenka, D.J., DeSimone, J.P., Leavitt, B.J., Helm, R.E., …O’Rourke, D.J. (2013). Effect of preoperative pulmonary hypertension on outcomes in patients with severe aortic stenosis following surgical aortic valve replacement. The American Journal of Cardiology, 112(10), 1635–1640.
- Aortic valve replacement (AVR) is the gold standard for surgical repair of severe AS; however, management of preoperative pulmonary hypertension may improve postsurgical outcomes for patients undergoing AVR.
- Among a sample of 1,116 consecutive patients who underwent AVR between 2005 and 2010, pulmonary hypertension was diagnosed in 48% (pulmonary systolic artery pressure [PSAP] > 34 mm Hg).
- In this sample, increased pulmonary hypertension was associated with a decrease in the 5-year survival rate post AVR (p = 0.006). Patients with severe pulmonary hypertension (PSAP > 59 mm Hg) were four times (p = 0.002) more likely to experience an acute kidney injury postoperatively and almost seven times (p = 0.001) more likely to experience in-hospital mortality post AVR than patients without pulmonary hypertension.
- Physical findings of systolic murmur, systolic thrill, and rales in the lungs
- Response to diuretics, nitrates, and rest
- Reaction to activity restrictions, fluid restrictions, and cardiac diagnosis
- Presence of complications: Chest pain, bleeding tendencies, labored breathing, fainting
Discharge and home healthcare guidelines
medications.Be sure the patient understands all medications, including the dose, route, action, adverse effects, and need for routine laboratory monitoring for anticoagulants.
complications of anticoagulants.Explain the need to avoid activities that may predispose the patient to excessive bleeding. Teach the patient to hold pressure on bleeding sites to assist in clotting. Remind the patient to notify healthcare providers of anticoagulant use before medical, surgical, or dental procedures. Identify foods high in vitamin K (green, leafy vegetables; oats; wheat; rye), which need to be eaten in a consistent amount, not binging, so that the effect of anticoagulants is not reversed.
teaching.Instruct the patient to report the recurrence or escalation of signs and symptoms of AS, which could indicate that the medical therapy needs readjusting or the replaced valve is malfunctioning. Patients with synthetic valves may hear an audible click like a ticking watch from the valve closure.
prevention of bacterial endocarditis.Patients who have had surgery are susceptible to bacterial endocarditis, which will cause scarring or destruction of the heart valves. Because bacterial endocarditis may result from dental work, surgeries, and invasive procedures, people who have repaired or replaced heart valves should be given antibiotics before and after these treatments.
Patient discussion about Aortic Valve Stenosis
Q. How does alcohol affect someone who has been diagnosed with aortic valve stenosis? My brother has been diagnosed with aortic valve stenosis and also is a smoker and does drink alcohol on the weekends. He knows that he should stop smoking but what about the effects of alcohol? Does this also contribute to his stenosis?
Q. Why does Aortic stenosis causes an enlarged heart? My father was recently diagnosed as suffering from enlarged heart due to his Aortic stenosis. what is the connection between those to conditions? As far as I understand that aortic stenosis mean that the aortic valve is too small not too large...
this is called Left Ventricular Hypertrophy or LVH in abbreviations.
this is a classic LVH E.C.G.