Mitral valve stenosis
The mitral stenosis ( mitral syn. ) is a valvular heart disease, in which the opening of the mitral valve is narrowed. Characterized occurs between two heart actions ( during diastole ) to a disturbed filling of the left ventricle.
Epidemiology
The mitral valve is one of the most common acquired valvular heart disease and affects women more often than men. In industrialized countries, the incidence was significantly lowered by the consistent use of penicillin for streptococcal infections in the past, so that they occur there nowadays less common than acquired aortic valve stenosis and Mitralklappeninsuffizienzen.
In about 40% of cases is a mitral stenosis in addition before aortic stenosis.
Etiology
By far the most common cause of mitral stenosis is rheumatic fever and the associated endocarditis (inflammation of the endocardium ). It typically occurs with a latency period of 20 to 30 years after the all-nighter fever disease. Endocarditis due to a bacterial infection or congenital mitral stenosis are rare.
Pathophysiology
The stenosis of the mitral valve is by inflammatory and degenerative changes of the valve leaflets and chordae tendineae of reasons. Fibrosis and calcification lead to a progressive reduction of the expansion and movement ability of the valvular apparatus.
The normal valve area is 4-6 cm2. Decreases this opening area by more than half, it hemodynamically significant interference occurs with the formation of a pressure gradient between the left atrium and left chamber. This results to a dilation ( expansion ) of the left atrium, which favors the occurrence of atrial fibrillation, and other pulmonary hypertension. This in turn also results in the disease progresses to a pressure load of the right heart, and as a result of right heart to right heart failure.
Clinic
A symptom is dyspnea (shortness of breath ) caused by the backflow of blood into the lungs. The dyspnea usually occurs only under load when the cardiac output is increased. In schwergradigen stenosis also a resting dyspnea may occur. Another symptom schwergradiger mitral stenosis may be hemoptysis ( coughing up blood ), particularly at night gets more intense dyspnea. In general, the physical performance of affected patients is reduced.
With many years of untreated course of a so-called Mitralgesicht (facies mitral ) with " red cheeks ", peripheral cyanosis and signs of right heart failure can set.
Sometimes the view of a mitral stenosis only drops by a diagnosis of tachyarrhythmia absoluta in atrial fibrillation. This occurs in advanced mitral stenosis on a regular basis and can be diagnostic groundbreaking. Frequently the initial manifestation, which leads to a diagnosis, caused by atrial fibrillation thromboembolism.
Diagnostics
The diagnosis is clear from history and clinical findings. The Leitgeräusch on auscultation is a low diastolic decrescendo with character. The maximum point is on the 5th ICR ( intercostal space ) to the left or near the apex of the heart.
More detectable on auscultation noise phenomena can be:
- Timpani Direction first heart sound
- Mitralklappenöffnungston ( MOET ) before the diastolic
Instrumental diagnostics
Further diagnostically usable variations include, inter alia:
- Chest x-ray: The chest X-ray shows a coarsening of the left heart waist, which is caused by a Vorbuchtung of the left atrium and the left atrial appendage. In the side image a narrowing of the esophagus through the left atrium may show up after Ösophagusbreischluck. May be noted as a sign of pulmonary hypertension basal Kerley B lines and a narrowing of the retrosternal space.
- ECG: The ECG often shows an excessive or bimodal P-wave (p mitral ) as an expression of atrial dilatation. Atrial fibrillation or atrial flutter may also be present. Signs of right heart failure occur in the form of a ball type or right type of heart axis at an advanced course.
- Echocardiography The echocardiography and allow Doppler echocardiography both the determination of the valve opening area, and the calculation of the pressure gradient. In addition, a possible concomitant mitral regurgitation present can be secured.
- Right heart catheterization: The right heart catheterization and additional ergometric stress on the pulmonary pressure above the normal level rises beyond.
- Left heart catheterization: the left heart catheterization allows direct determination of the pressure gradient and valve area. For this, the pressure in the left ventricle and in addition the wedge pressure can be determined (by means of pulmonary artery catheter ).
Classification of severity
A mitral stenosis can be divided into three levels of severity as determined by the valve area ( KÖF ).
- Mild: KÖF greater than 1.5 cm2
- Moderate: KÖF between 1.0 and 1.5 cm2
- Severe: KÖF less than 1.0 cm2
There is also the possibility of a more complex classification:
1For a heart rate of 60 bpm ) 2In the case of presence of a normal pulmonary artery pressure. The transition between mild and moderate form is not precisely defined
Therapy
The therapeutic options include conservative control of complications and operative (alternatively via catheter ) correction of the stenosis.
In mild mitral stenosis, conservative treatment by physical inactivity and the use of diuretics (water resources) can take place. If in addition a relevant pulmonary hypertension before, a therapy with vasodilators ( vasodilator substances, such as nitrates ) can be helpful.
If there is a recurrent atrial fibrillation with risk of cardiac embolism, anticoagulation with warfarin should be done. For faster transfer of atrial fibrillation on the chambers digitalis and beta blockers or verapamil can be used for frequency control.
ACE inhibitors are contraindicated.
Before bloody interventions and febrile consistently antibiotics for prophylaxis of endocarditis should be taken.
A surgical or interventional therapy is useful in each case with severe symptoms and a schwergradigen mitral stenosis. An intervention should not be delayed too long, because the prognosis of mitral stenosis is usually also deteriorated after surgical therapy.
As an operative / interventional procedures are available:
- Mitralklappenvalvuloplastie ( distention by balloon catheter )
- Mitralklappenkommissurotomie
- Mitral valve repair
- Mitral valve replacement (biological or mechanical valve )
Forecast
In general, the prognosis of Mitralklappenverengung is better than the other valvular. In severe stages, however, the survival time of patients is significantly reduced without treatment. In NYHA class III live without treatment after five years around 60 % of patients. In the highest NYHA class IV still around 15%. Leading causes of death are the insufficiency of the right heart, a resulting from the increase in pressure in the left atrium and pulmonary embolism. The five- year survival rate can be increased by adequate surgical treatment to over 80%. However, the surgery involves the risk of dying during this. It is depending on the method and study between one and five percent. The Kommisurotomie is less risky than a valve replacement.