Mitral Regurgitation – Symptoms, Diagnosis And Treatment
Return of a volume of blood from the left ventricle into the left atrium during ventricular systole as a result of incompetence of closing of mitral valvular apparatus characterize mitral regurgitation.
Various pathological processes can affect one or more constituents of the mitral valvular apparatus, resulting a lack of closure of the two mitral cuspe. Rheumatic disease still represents a etiology in some underdeveloped countries while degenerative and ischemic diseases passed on first place as the etiology of mitral regurgitation. Mitral valve prolapse is a disease with a not enough clarified etiology, which may progress to severe mitral regurgitation that requires surgery. Endocarditis, by the destruction process of the endocard can lead to mitral regurgitation. In terms of installation of mitral regurgitation phenomena, exist an acute form with sudden onset, either by rupture of the cusps, cordage in cardiac ischemic disease or endocarditis and chronic mitral regurgitation that progresses slowly.
It is different in acute form of mitral regurgitation from the chronic form of mitral regurgitation, because the regurgitant volume, overload suddenly the left atrium and pulmonary circulation and lead to pulmonary edema and cardiogenic shock. In this situation is needed emergency surgery to save patient’s life. In the chronic form of mitral regurgitation, adaptive mechanisems represented by left ventricle and left atrium hypertrophy, keep for a long period of time the patients asymptomatic. With the overcoming of this phase and installation of cardiac decompensation phenomena, left and right ventricular pressure will be increased, pulmonary pressure will be increased and patients become severely symptomatic.
Symptoms and diagnosis of mitral regurgitation:
Chronic mitral regurgitation can be tolerated for years without symptoms. In time, will appear asthenia, dyspnea, orthopnoea, nocturnal attacks of dyspnea, palpitations and peripheral edema. In the acute form of mitral regurgitation which is more common in coronary artery disease, myocardial infarction with rupture of cordage, sudden and severe symptoms are installed which are evolving to acute pulmonary edema and cardiogenic shock. The clinical examination show a hyperdinamic apexian shock, move left by left ventricle hypertrophy. On auscultation, it is heard a characteristic holosistolic murmur, with irradiation in the left axilla.
Once the suspicion of the existence of mitral regurgitation by physical examination the patient is fully investigated for objective assessment of lesion severity.
Cardiothoracic radiography. Initial, cardiac silhouette is normal, then increases by the increasing of the left atrium and left ventricle, in advanced forms, reaching impressive size.
Electrocardiogram. Reflected the left atrium and left ventricle hypertophy , by changing the P wave, which becomes “mitral” and changing QRS axis deviation to the left. Atrial fibrillation once installed, can remain even after surgery. The presence of acute or chronic coronary artery disease, sequelae of myocardial infarction with Q wave, may explain some forms of mitral regurgitation which are unknown by the patient until then.
Echocardiography. Is an indispensable investigation by the information brought about the etiology of mitral regurgitation disease and its consequences. More, intraoperative echocardiography is indispensable when is tempted the mitral valve reconstruction. The value of echocardiography in the diagnosis of mitral regurgitation is important, because:
- Confirm and quantify the mitral regurgitation and the repercussions on the left ventricular function;
- Identify the mechanism of regurgitation, ring expansion, retraction or rupture of cordage;
- Investigate the other valves: aortic, tricuspid and pulmonary valve;
- Rate functional or structural tricuspid regurgitation and pulmonary hypertension;
- Orientate the surgical option, for replacement of the mitral valve or mitral valve plasty;
- Tracing the consequences of a myocardial infarction;
- Periodic monitoring of asymptomatic forms of mitral regurgitation, to choose the optimal time for surgical intervention.
Cardiac catheterization. It is required to confirm or rule out coronary artery disease as a etiologic mechanism. In patients with known angina pectoris, sequelae of a myocardial infarction and those with cardiovascular risk factors irrespective of age and accuracy of echocardiography, cardiac catheterization is indicated. Rate and quantify with high sensitivity regurgitant blood volume, left ventricular function, pulmonary hypertension and tricuspid regurgitation.
The prognosis of these patients depends on the etiology, the severity of mitral regurgitation and left ventricular function. Evolution even in patients with significant mitral rehurgitation may be spread over decades until decompensation. But once decompensation installed, the operator risk increases and postoperative results are weaker, facts that should be taken into account, when choosing the best time for surgical intervention. Dilatation of left atrium with atrial fibrillation installation, will increase up to 10% – 20%, the incidence of cerebral embolic complications and peripherals embolic complications. The study revealed that 80% of patients with mitral regurgitation remain alive at 5 years and 60% at 10 years . Natural evolution is much worse in mitral regurgitation due to coronary disease.
Medical treatment. Prophylaxis of infectious endocarditis in patients with known mitral regurgitation is very important. Vasodilators, antiarrhythmics for atrial fibrillation, diuretics and anticoagulant treatment improves much the clinical status, but should not delay the surgical intervention, until will appear severe left ventricular decompensation.
Surgical treatment. It is only rational treatment to a point in the evolution of mitral regurgitation. Surgical decision and the best time is harder to assess. The current trend is that the surgical intervention should be done sooner, before left ventricular decompensation and the recommendation is to be used reconstructive techniques rather than mitral valve replacement.
Surgical indication is made depending on the severity of mitral regurgitation, clinical status of patients, symptomatic or asymptomatic and the effects on left ventricular function:
- Symptomatic patients with severe mitral regurgitation and ventricular dysfunction, left ventricular ejection fraction < 60% and end-systolic diameter of left ventricle > 45 mm;
- Asymptomatic patients with mitral regurgitation, when the echocardiographic data and angio show left ventricular dysfunction;
- Mitral regurgitation with atrial fibrillation, because after surgery is likely to return to sinus rhythm.