Mitral Valve Disease

The dynamic mitral valve is prone to three diseases, which are known as mitral stenosis (MS), mitral regurgitation (MR), and mitral valve prolapse (MVP). As a key anatomic and functional structure, advanced disease of this valve may lead to complications such as heart failure and death [1].

MS is commonly caused by rheumatic fever, which is rare in industrialized countries but still prevalent in developing regions. The disease presents in young adults usually in the third or fourth decade with symptoms such as fatigue, palpitations, chest pain, hemoptysis [2]. When MS progresses, the patient may experience dyspnea on exertion, orthopnea, as well as paroxysmal nocturnal dyspnea [3]. Among the clinical features are jugular vein distension and a displaced apical impulse. On auscultation, there is a loud S1 (first heart sound), split S2 (second heart sound), an opening snap, and a diastolic rumble.

MR typically develops as a consequence of aging mechanisms, ischemic disease, rheumatic fever, or prolapse [2] [4]. There are two forms of MR, which are acute (rare) and chronic. Often the result of valvular infection, the presentation of acute MR mimics that of acute heart failure. However, chronic MR evolves gradually and may be asymptomatic in the early stages. Features include fatigue, dyspnea, palpitations, and so forth. Auscultation findings include an apical holosystolic murmur with a soft S1, split S2, and possibly a third heart sound (S3).

MVP is found in up to 3% of the population [5] and is more predominant in young women [2]. While many individuals with prolapse do not exhibit symptoms, some will have fatigue, dizziness, dyspnea, palpitations, chest pain, anxiety, and presyncope. The palpitations may be triggered by emotional stress. The hallmark murmur is a mid-to-late systolic click.

Individuals with a clinical presentation suggestive of mitral valve disease warrant a thorough workup consisting of the patient and family history, physical exam including auscultation [2], and the appropriate studies.

Laboratory tests

The workup should include a complete blood count (CBC) a complete metabolic panel (CMP).

Imaging

Echocardiography is a critical component of the assessment since it is noninvasive, accessible, and provides information for diagnosis and monitoring of the disease [6]. This modality is sensitive and specific for identifying MS [7] and is the key for diagnosing MR and MVP [8]. This study also allows the clinician to determine the etiology and stage of the valvular abnormality and functionality and size of the atria.

Transthoracic echocardiogram (TTE) reveals mobility, calcification, and thickening of the valve [9]. Moreover, real-time 3-dimensional transesophageal echocardiography (TEE), which is superior to TTE, offers excellent images of the mitral valve [10]. Very importantly, TEE is very beneficial in cases suggestive of endocarditis or presence of thrombi.

Chest radiography is another important investigative study. In patients with MS, a chest X-ray will likely display calcification of the mitral valve, left atrial enlargement, interstitial edema, and prominent pulmonary vasculature. In patients with chronic MR, chest X-ray findings may include left ventricular and left atrial enlargement, and evidence of heart failure such as pulmonary congestion. Similar observations are found in patients with MVP associated with MR.

Other imaging tests such as ventriculography and cardiac magnetic resonance imaging (MRI) may be utilized to measure the regurgitation.

Electrocardiography (EKG)

An EKG is obtained in all patients with cardiac complaints. A typical finding in patients with advanced MS is atrial fibrillation. Other remarkable features include prolonged P wave in lead II, which is indicative of left atrial hypertrophy. Features associated with chronic MR are left ventricular and left atrial hypertrophy, and ST segment changes in lateral leads. Additionally, there are P wave abnormalities in various leads. Occasionally, MVP is associated with benign arrhythmias.

Procedures

Cardiac catheterization is performed selectively prior to surgery. Also, stress EKG is used periodically to monitor MR.

1. Levine RA, Hagége AA, Judge DP, et al. Mitral valve disease—morphology and mechanisms. Nat Rev Cardiol. 2015;12(12):689-710.
2. Turi ZG. Mitral Valve Disease. Circulation. 2004;109(6):e38-41.
3. Carabello BA. Modern Management of Mitral Stenosis. Circulation. 2005;112(3):432-437.
4. Enriquez-Sarano M, Schaff HV, Frye RL. Mitral regurgitation: what causes the leakage is fundamental to the outcome of valve repair. Circulation. 2003;108(3):253-6.
5. Freed LA, Levy D, Levine RA, et al. Prevalence and clinical outcome of mitral-valve prolapse. N Engl J Med. 1999;341(1):1–7.
6. Hung JW, Tan TC. Echocardiography in mitral valve disease. Preface. Cardiol Clin. 2013;31(2):ix-x.
7. Wunderlich NC, Beigel R, Siegel RJ. Management of mitral stenosis using 2D and 3D echo-Doppler imaging. JACC Cardiovasc Imaging. 2013;6(11):1191-205.
8. Dal-Bianco JP, Levine RA. Anatomy of the mitral valve apparatus: role of 2D and 3D echocardiography. Cardiol Clin. 2013;31(2):151–164.
9. Bruce CJ, Nishimura RA. Newer advances in the diagnosis and treatment of mitral stenosis. Curr Probl Cardiol. 1998;23(3):125-92. Review.
10. Schlosshan D, Aggarwal G, Mathur G, Allan R, Cranney G. Real-time 3D transesophageal echocardiography for the evaluation of rheumatic mitral stenosis. JACC Cardiovasc Imaging. 2011;4(6):580-8.