Mitral Regurgitation (MR)

Mitral Regurgitation (MR)

Mitral Regurgitation (MR)

Dec 7, 2023


Mitral regurgitation is one of the valvular heart diseases that can be primary or secondary. Determining the type and cause is essential to manage the disease properly.  

Primary Mitral regurgitation results from a primary defect of one or more components of the valve apparatus. Mitral valve prolapse is considered the most common cause of Primary MR in high-resource countries whereas rheumatic heart disease in low-resource countries. 

Secondary mitral regurgitation is a result of other diseases such as coronary heart disease.


Primary MR:

In Mitral valve prolapse, the more than usual stretching of the mitral valve and excessive tissue and surface area result in redundancy, folding, and hooding affecting anterior or posterior leaflets or both which is called myxomatous degeneration, known as Barlow syndrome. Dilated annuals which are usually disconnected from the typical myocardial support, might develop over time and  have a role in the worsening of the condition. In older adults, elongated chordae, fibroelastic deficiency, and lack of connective tissue support might lead to chordal rupture. 

In acute rheumatic carditis, the inflammation of chordal structures and mitral valve leaflets leads to Mitral regurgitation whereas in infective endocarditis, the vegetation, chordal rupture, and valve deformities might be the leading causes.

Secondary MR: 

As secondary MR results from an underlying condition or substance, multiple factors are responsible for the pathophysiology of the condition; atrioventricular dysfunction and remodeling are examples.


Primary mitral regurgitation:

  • A transthoracic echocardiogram is indicated (from stages A-D) for baseline evaluation of LV size and function, RV function, LA size, pulmonary artery pressure, and severity and mechanism of primary MR.
  • When transthoracic echocardiogram is insufficient, transesophageal echocardiogram to evaluate the severity of MR and LV function is indicated in stages B to D.
  • If the findings between clinical assessment and echocardiography are inconsistent, cardiovascular magnetic resonance is indicated.
  • In severe primary MR (Stages C and D), intraoperative Transesophageal echocardiogram is indicated in patients undergoing mitral intervention to detect anatomical basis and guide repair. 
  • In patients with new-onset or change in symptoms (from stages B–D), a transthoracic echocardiogram is indicated to evaluate mitral valve apparatus and LV function.

Secondary mitral regurgitation:

  • Patients with stages B to D: Transthoracic echocardiogram is useful in detecting the etiology, severity of the disease, extent of LV remodeling and systolic dysfunction, and magnitude of pulmonary hypertension.  
  • Patients with stages B to D: non-invasive imaging (eg: stress echocardiography), coronary CT angiography, or coronary arteriography is useful to detect the etiology of MR and myocardial viability.
  • In Stage D patients (severe symptoms) who are unresponsive to the GDMT (ARNI, beta blocker, mineralocorticoid receptor antagonist, and SGLT2 inhibitor) and are undergoing transcatheter mitral valve intervention, a transesophageal echocardiogram is indicated to assess the appropriateness of the intervention preoperatively. It is also indicated intraoperatively for guidance.


Types of MR



Primary MR

-Symptomatic OR asymptomatic

-Severe  MR and systolic dysfunction (C2 and D)

-Not fit for surgery or should be delayed.

GDMT is reasonable

-Severe Stage D


Mitral valve intervention, irrespective of LV systolic function


-Severe MR

-LV systolic dysfunction (LVEF<=60, LVESD >=40 mm).

Mitral valve surgery is recommended

-Severe MR

-Surgery indicated

-MR cause is degenerative disease

Mitral valve repair is preferred over mitral valve replacement if successful and durable repair is achievable.

-Asymptomatic and severe MR

-Normal LV systolic function (LVEF >=60, LVESD <=40 mm)🡪stage C1

Mitral valve repair is reasonable if:

-Likelihood of successful and durable repair without residual MR is > 95%.

-Expected mortality rate < 1%

 -Performed at primary or comprehensive valve center

-Asymptomatic severe MR

- Normal LV systolic function (LVEF >60, LVESD <40 mm)🡪stage C1

-Progressive increase in LV size OR decrease in EF on >=3 serial imaging studies. 

Mitral valve surgery might be considered regardless of success or durable repair.

-Severe symptoms (NYHA class III or IV)

-Severe MR

-High surgical risk

-Patient's life expectancy >= 1-year

TEER (transcatheter edge-to-edge repair) is reasonable if valve anatomy is favorable for repair

-Symptomatic Severe MR related to Rheumatic valve disease


Mitral valve surgery might be considered if surgery is indicated.

-Perform in a comprehensive valve center by an experienced team if durable and successful repair is likely.

-Severe MR

- Involvement of the posterior leaflet is less than one-half  

No Mitral valve replacement is necessary unless mitral valve repair was done at the primary or comprehensive valve center and was unsuccessful.

Secondary MR

-Severe MR (stages C and D)


GDMT under the supervision of a specialist.

-Severe MR

-LVEF<50% with persistent symptoms (NYHA II, III OR IV) on GDMT

TEER is reasonable if:

- Appropriate anatomy on TEE

-LVEF 20-50%

-LVESD<=70 mm

-Pulmonary artery systolic pressure<=70 mmHg

-Severe MR (stages C and D)

-CABG undertaken for myocardial ischemia

Mitral valve surgery is reasonable.

-Severe MR from atrial annual dilation

-Preserved LV function >=50% with severe persistent symptoms (NYHA III or IV)

-Already On HF or AFIB therapy.

Consider Mitral valve surgery

-Severe MR from LV systolic dysfunction (LVEF<50)

-Persistent symptoms (NYHA III or IV) while on GDMT

Consider Mitral valve surgery.

-Severe MR from LV systolic dysfunction (LVEF<50)

-Coronary artery disease

-Undergoing MV surgery because of severe symptoms (NYHA III or IV) despite GDMT

Chordal sparing and mitral valve replacement are reasonable



  1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Valvular-Heart-Disease-Guidelines 
  2. https://www.uptodate.com/contents/chronic-primary-mitral-regurgitation-indications-for-intervention
  3. https://www.uptodate.com/contents/pathophysiology-and-natural-history-of-chronic-mitral-regurgitation
  4. https://www.jacc.org/doi/pdf/10.1016/j.jacc.2020.11.018?_ga=2.42406501.1938884270.1698608914-977878038.1614442144  

Latest News