Lectures on mitral stenosis

2021-08-13 06:31 PM

Doppler ultrasonography is the most accurate noninvasive exploratory method for quantifying the extent of mitral stenosis and assessing pulmonary artery pressure.

Mitral stenosis

Healthy mitral valve vs Mitral valve stenosis

Definition and etiology

Mitral stenosis, a blockage of blood flow between the left atrium and left ventricle, is caused by abnormal mitral valve function.

Mitral valve area: 4-6cm2: normal, <2cm2 (<1.18cm2/m2 body skin area): mild stenosis, <1.5cm2: moderate stenosis,<1cm2 (<0.6cm2/m2 area) body skin).

99% caused after rheumatic heart disease, of which simple mitral disease accounts for 25% (2/3 is female), mitral regurgitation accounts for 40%. Other causes: congenital, carcinoid syndrome, systemic lupus erythematosus, rheumatoid arthritis, Hunter-Hurler phenotype mucopolysaccharidoses, Whipple's disease, Fabry's disease, due to Methiserzide use.

Diagnostic criteria

Medical history.

History of acute rheumatic fever or heart murmur, although some patients do not remember this.

Dyspnea or exertion fatigue: The main complaint, often initiated by exertion, fever, anemia, atrial fibrillation, or pregnancy, dyspnea when lying down, progresses to paroxysmal nocturnal dyspnea.

Hemoptysis, due to the rupture of thin dilated bronchial veins.

Chest pain due to right ventricular ischemia, atherosclerosis, or concomitant coronary artery embolism.

Systemic embolism can be the initial symptom of mitral stenosis, about 50% causing cerebral vascular occlusion.

Nervousness, dry cough, and hemoptysis are common in patients with pulmonary hemosiderin stasis.

Infective endocarditis.

Compression of the recurrent nerve from an enlarged left atrium enlarged lymph nodes in the trachea, or an enlarged pulmonary artery can cause hoarseness (Ortuer's syndrome).

Clinical examination: The clinical findings depend on the disease progression and the degree of cardiac decompensation.

Look: thin, mitral expression, jugular veins

Palpate the apex of the heart:

Strong T1, apical diastolic fibrillation (patient lying on the left side is more obvious).

Anterior thoracic sign: Right ventricular bulge on the left sternal border in a patient with pulmonary hypertension.

A strong P2 is palpable in the left 2nd intercostal space in a patient with pulmonary hypertension.

Listen:

T1 sharp, increased QT1 interval correlated with increased left atrial pressure.

P2 is strong, apex audible. When pulmonary artery pressure increases much, the distance A2 - P2 shortens and finally, T2 re-enters to a single and strong sound.

Pulmonary ejection click, the asystolic murmur of tricuspid regurgitation, T4 of the right ventricle.

The valve opening is best heard at the apex.

Low-frequency diastolic murmur of mitral stenosis (diastolic fibrillation).

Heard the best apex, patient in the left lateral position, with a stethoscope bell.

The length of the new diastolic fibrillation reflects the degree of stenosis.

Subclinical

ECG:

Often Typical changes in moderate to severe mitral stenosis.

Signs of left atrial enlargement, right ventricular enlargement.

Atrial fibrillation often occurs on an ECG that presents with left atrial enlargement and correlates with left atrial size, degree of left atrial muscle fibrosis, duration of left atrial enlargement, and age of the patient.

The QRS axis is correlated with the degree of stenosis and pulmonary vascular resistance in patients with simple mitral stenosis.

X-ray:

Moderate-severe mitral stenosis.

The main bronchus (left) is pushed up, the descending aorta is pushed through (left).

A straight film with Baryte: esophagus can be displaced, usually transverse (right), sometimes displaced (left). The anterior oblique film (P) of the esophagus is most clearly pushed posteriorly.

The eardrum (left) is getting bigger day by day, especially when there is atrial fibrillation. The atrium (left) may extend beyond the atrial margin (right), showing a double border at the (right) border of the heart.

The aortic arch is also enlarged due to increased pressure in the ventricular chamber (right).

The atrial appendage (left) is enlarged, represented by the 4th arch (left), just below the pulmonary artery. This is the earliest sign of mitral stenosis.

The border (left) of the heart may also present as a straight or protruding line.

Varicose veins of Azygos (>7mm).

The ventricle (left) has normal size, the heart/thoracic index <= 0.5, later the (right) ventricle is dilated (increased T/N index).

Rare images are calcifications of the mitral valve (40%), mitral annulus (10%), and in the atrial wall (left).

Tilt film (left): The atrium (left) is enlarged and pushes the main bronchus (left) backward (Walking man sign).

Echocardiography:

It is the cornerstone test for the evaluation of patients with mitral stenosis. Careful echocardiography and doppler echocardiography can help plan treatment strategies without cardiac catheterization.

The appearance of thickened, calcified, narrow valves, the reduced valve opening amplitude during diastole can be seen by two-dimensional ultrasound through the chest wall or through the esophagus. The valves do not close during mid-diastole and may not open wider during atrial contraction in patients with sinus rhythm.

Large left atrium.

The left ventricle is not enlarged in patients with simple mitral stenosis.

Image of eddy or thrombus in the left atrium and left atrium.

When the leaflets are thickened and fibrous, the orifice can be directly visualized and measured by planometry.

Echocardiography helps to evaluate the tenderness of the leaflets, the degree of valve calcification, the thickening of the subvalve, adhesions and contractures of the ligaments, and calcification of the annulus.

This technique allows the determination of left ventricular chamber size and function and assessment of the aortic valve.

Two-dimensional echocardiography is useful in determining whether a patient can undergo balloon angioplasty by assessing the Wilkins index.

Transesophageal echocardiography provides a better image of the mitral valve than transthoracic echocardiography and is more sensitive in detecting left atrial and atrial appendage thrombus.

Doppler ultrasonography is the most accurate noninvasive exploratory method for quantifying the extent of mitral stenosis and assessing pulmonary artery pressure. Color Doppler increases the accuracy of doppler data by identifying the presence of aortic regurgitation or other associated abnormalities. Pulmonary artery pressure can be calculated from the tricuspid regurgitation flow.

Treatment

Medical

Rheumatic heart disease prevention: Penicillin 1.2 million units (intramuscular) every 3 to 4 weeks for life.

Prophylaxis of infective endocarditis for bleeding procedures.

Treatment of predisposing factors for heart failure: anemia, infection, physical exertion.

Symptomatic treatment

Heart failure:

Eat light and diuretic.

Digital: not indicated in patients with sinus rhythm. Indicated in patients with atrial fibrillation to control ventricular response and in patients with right heart failure.

Beta-blockers and calcium channel blockers have a slowing effect that increases exercise capacity by slowing the heart rate in patients with sinus rhythm and especially in patients with atrial fibrillation.

Hemoptysis: by actively reducing pulmonary venous pressure.

Sedative.

Lie tall or sit up straight.

Strong diuretic.

Prophylaxis of deep vein thrombosis and pulmonary embolism in patients with prior pulmonary embolism or at high risk of systemic embolism: Chronic or episodic AF, > 70 years of age, history of embolism. Use warfarin to maintain an INR between 2 and 3, but there is no definitive evidence that anticoagulants reduce the risk of embolism in patients with sinus rhythm without a history of embolism.

Treatment of arrhythmias:

Electric shock with rhythm.

Immediate treatment of atrial fibrillation with medication.

Cardioversion by electric shock combined with drugs.

Patients with chronic atrial fibrillation undergoing open-heart surgery can use Cox, Maze's atrial partitioning technique to maintain sinus rhythm after surgery in 80% of patients.

Tips

Mitral valve dilation with Inoue balloon.

Mitral valve replacement:

The anatomical classification of the mitral valve (WILKINS)

Valve opening amplitude

The valve opens well, limited to the valve edge only.

The range of openings in the middle and bottom of the leaflets is limited.

The leaflets move anteriorly during diastole, mainly in the basilar region.

No or very little forward movement of the leaflets

Valve blade thickness

Near normal (4 – 5mm).

Thicken the middle part of the valve leaf, thicken the edge of the valve.

The thickness of the entire valve leaflet (5 – 8mm).

The thickness of the entire valve leaf (>8 - 10mm ).

Thick under valve

Mild thickening of the ligaments just below the leaflets.

Up to 1/3 of the length of the ligament.

Up to 1/3 of the distal ligament.

Thickens and shortens all ligaments to the ulnar muscle.

Calcification of valve leaflets

1 single area of ‚Äč‚Äčecho amplification.

Scattered areas of luminosity at the margins of the leaflets.

Calcification to the center of the valve.

Calcification is abundant near the entire valve leaflet.

Index = total score of all 4 items.