Mitral Regurgitation

General Information

Global prevalence: > 2%

Murmur: high-pitched holosystolic murmur best heard at the apex and radiates to the axilla

(Free) Beginner material:

Mechanisms of Mitral Regurgitation

Figure 1. Mechanisms of MR

Figure 1 lists some mechanisms of MR. The simplest way to understand the cause of MR is to differentiate between primary (valvular problem) and secondary (chamber problem). Secondary MR is caused by a dilated left atrium (functional atrial MR) or a problem with the left ventricle. Primary MR is an issue with the mitral valve apparatus (Figure 2).

Figure 2. Mitral valve apparatus. Citation: CardioServe

Classification of MR

Figure 3. Carpentier Classification

MR is classified by the Carpentier classification. Type 1 is a normal leaflet. Type II is excessive leaflet motion (mitral valve prolapse). Type IIIA is restricted motion in both systole and diastole, while IIIB is restricted motion in systole only. A mixed picture is also possible.

Mitral valve severity

Transthoracic echocardiography (TTE) is often used to diagnose. If TTE does not clearly understand the severity or mechanism, transesophageal echocardiography (TEE) may be helpful in further delineating it. Cardiac MRI may also be helpful in some cases.

	Mild	Moderate	Severe
EROA (cm2)	< 0.20	0.2 – 0.39	≥0.4
Regurgitant Volume (mL)	< 30	30 – 59	≥ 60
RF (%)	< 30	30 – 49	≥ 50

Table 1. Echocardiography criteria for mitral regurgitation severity

Additional Criteria are provided in the table below.

Severe mitral regurgitation

§Flail leaflet

§Vena contracta width ≥ 0.7 cm

§Vena contracta area ≥ 0.5 cm2

§PISA radius ≥ 1.0 cm at Nyquist limit of 30-40 cm/s

§Central jet > 50%of the left atrial area

§Pulmonary vein systolic flow reversal

§Enlarged LV with normal systolic function

Table 2. Additional criteria for severe mitral regurgitation

Mitral Valve Regurgitation Echo Calculations

Figure 4. Echocardiography calculations for mitral regurgitation severity

Mitral regurgitation severity can be estimated using the flow convergence or Continuity equation method. The Continuity equation assumes continuity of flow from the mitral valve into the LVOT.

Surgical Indications for MR

Figure 5. Indications for surgery in patients with mitral regurgitation

All symptomatic patients should be referred to surgery.
Repair is preferred over replacement.
In secondary (functional) MR, asymptomatic patients should be monitored.
In primary MR, asymptomatic patients should be considered for surgery if conditions in Figure 5 are met.