Valvular heart disease Flashcards
2 Atrioventricular Valves
Valves that connect the atria to the ventricles
Mitral valve - connects the left atrium to the left ventricle
Tricuspid valve - connects the right atrium and right ventricle
2 semilunar valves
Semilunar valves are the valves connecting the ventricles to the great vessels
Aortic - connects the left ventricle to the aorta
Pulmonic - connects the right ventricle to the pulmonary artery
Valvular heart disease is defined according to:
- valve (s)
- functional alteration:
a) stenosis
b) regurgitation
Stenosis
- Valve orifice restricted
- Forward blood flow impeded
- Pressure gradient across open valve - increases because of the increased resistance to flow.
Regurgitation
- (aka) valvular incompetence or insufficiency
- incomplete closure of valve leaflets
- results in backward flow of blood
Mitral Stenosis: what causes it?
most cases are from rheumatic heart disease
rheumatic mitral stenosis is most prevalent in developing countries
What is mitral stenosis and how does it effect pressure gradient in the heart
Contractures & adhesions between commissures - > structural deformities -> obstruction of blood flow -> results in pressure difference between LA & LV
increased pressure and volume in LA and increased pulmonary vascular pressure - pulmonary hypertension
How does rheumatic endocarditis effect the valves
causes scarring of valve leaflets & cordae tendineae
Clinical Manifestations of mitral regurgitation
Acute and Chronic
Acute: thready pulses, cool, clammy extremities
Chronic: may be asymptomatic for years, symptoms of LV HF
Clinical Manifestations of Mitral Stenosis (5)
- Exertional dypsnea (d/t decreased lung compliance)
- Atrial fibrillation (fatigue, palpitation)
- hemoptysis (pulmonary hypertension)
Symptoms of LV HF
weakness, fatigue, d/t decreased CO, dyspnea gradually progressing to orthopnea, nocturnal dyspnea, respiratory distress that awakens the patient, exertional dyspnea
Mitral Valve Regurgitation
Incomplete mitral valve closure
Blood flows backward from LV to LA during systole
LA and LV have to work harder to generate adequate CO
Eventual enlargement of LA, ventricular hypertrophy and dilation
Mitral Valve Regurgitation is related to defect from: (5)
Mitral leaflet
Mitral annulus
Chordae tendineae
Papillary muscles
LA & LV
Most cases of Mitral Valve Regurgitation are caused by: (5)
MI, chronic rheumatic heart disease, mitral valve prolapse, ischemia of papillary muscles, or infective carditis
Aortic Stenosis
causes a thickening and narrowing of the valve between the LV and aorta. narrowing creates a smaller opening for blood to flow through. blood flow from the heart to the rest of the body is reduced or blocked
Causes obstruction of blood flow from LV to aorta during systole -> LV hypertrophy and increased myocardial O2 consumption
Congenital aortic stenosis
usually discovered in childhood, adolescence, or young adulthood
Aortic Stenosis In older adults
result of rheumatic fever or degeneration
In rheumatic fever
fusion of commissures and secondary calcification - causes valve leaflets to stiffen and retract -> results in stenosis
IF AS is from rheumatic fever what accompanies it?
mitral valve disease
Aortic Valve Regurgitation
May be result of primary disease of aortic valve leaflets or aortic root
Backward blood flow from aorta - into left V, when aortic v should be closed which results in volume overload
Causes of Acute AR (3)
from infective endocarditis, trauma, aortic dissection
causes of chronic AR
generally results of rheumatic heart disease, a congenital bicuspid aortic valve, syphilis
Clinical manifestations of Aortic Valve Stenosis: Classic triad and how much does it have to be stenosed to get these?
Symptoms develop when valve orifice decreases to 1/3 of its normal size
1. Angina
2. Syncope
3. Exertional dyspnea
Should nitro be given in aortic valve stenosis?
Use of nitro is not recommended because it reduces preload (by vasodilating veins) and preload is necessary to open the stiffened aortic valve and can cause significant decrease in BP.
- preload is the amount of stretch your heart has when it is most full right before it empties.
Clinical manifestations of Aortic valve regurgitation: acute
sudden manifestation of severe dyspnea, chest pain, progression to shock
Clinical manifestations of Aortic valve regurgitation: Chronic
Exertional dyspnea, fatigue, orthopnea, paroxysmal nocturnal dyspnea
Water hammer pulse - a strong quick beat that collapses immediately
Generally asymptomatic for years, then presents with symptoms after myocardial dysfunction has occured
Conservative management of Valvular Heart Disease
Prevention of recurrent rheumatic fever and infective endocarditis
Depends on the valve involved and severity of disease
Preventing exacerbation of HF, acute pulmonary edema, thrombo-embolism, and recurrent IE
If signs of heart failure
- vasodilators, positive inotropes, beta-blockers, low sodium diet, diuretics
Percutaneous Aortic Valve Replacement
For people who are at high risk for surgical treatment
Replacement via femoral artery, performed in catheterization lab
Percutaneous Transluminal Balloon Valvuloplasty
Splits open fused commissures
Used for mitral tricuspid and pulmonic. less often for aortic
Are valve surgeries curative?
Surgical all-types of valve surgery are palliative not curative and the patient will require life-long health care.
Mechanical prosthetic valves
More durable and lasts longer
Increased risk of thrombo-embolism, require long-term anticoagulation therapy
Biological prosthetic valves
Bovine, porcine, and human cardiac tissue
Does not require anticoagulant therapy
Less durable
Diagnosis for valvular heart disease
Based on
History
Physical Exam
Echo - shows valve structure, function & chamber size
Cardiac Catheterization (esp surgical option)
- reveals pressure changes in cardiac chambers, measures pressure gradients across valves and quantifies the size of valve openings
Post-op Nursing Care: ICU (8)
hemodynamic monitoring - continuous VS, q15 min initially. 12-lead ECG
resp: ventilated, routine ABG, respiratory therapists role
CXR
Pain control (IV morphine, PO T3
Accurate I&O (manage blood loss, chest tube output q1h, U/O, CVP q1h
N/G to intermittent low wall suction
Wound: sternal incision
Mobility - post-extubation/PT
Post-op Nursing Care: Stepdown Unit (8)
- H2T physical assessment
- Pain control (PO T3)
- Titrate O2 to maintain SpO2 > 95%
- D/C CVP lines, chest tubes, Foley cath
- Dangle (sit up) on the edge of bed; may sit up in chair
- Electrolyte replacement (may use diuretics)
- Resume cariac meds and pre-op meds & subcut heparin
- DB &C q1h while awake & mobilize
