Approach Considerations
Key considerations regarding diagnostic studies from the 2017 American College of Cardiology (ACC) expert consensus decision pathway on the management of mitral regurgitation (MR) include the following [11, 12] :
-
Exercise testing can be useful for assessment of functional status and symptomatic elicitation; and exercise echocardiography may reveal elevated pulmonary artery pressures, MR worsening, or blunted left ventricular (LV) or right ventricular (RV) contractile reserve.
-
Determine the mechanism and etiology of MR, usually with transthoracic echocardiography (TTE), or, if the image quality is poor, with transesophageal echocardiography (TEE). Perform assessment of the mitral apparatus, careful measurement of left atrial (LA) volume, and LV diameter and volume.
-
Distinguish between primary MR (due to abnormalities of the mitral leaflets or subvalvular apparatus) and secondary MR (due to LA or LV geometric changes with a functionally normal mitral valve). In addition to LV dilatation or regional or global abnormalities of LV systolic function, secondary MR also can be caused by pure LA and mitral annular dilation (ie, "atrial functional MR").
-
After characterization of leaflet morphology, describe the leaflet motion using the Carpentier classification system: type I (normal leaflet motion); type II (excessive leaflet motion); and type III (restricted leaflet motion), subcategorized as type IIIA (restricted during both systole and diastole) and type IIIB (restricted only during systole).
-
The initial assessment of the MR severity should be with color-flow Doppler ultrasonography, and it should include quantitative parameters such as the effective regurgitant orifice area, regurgitant volume, and regurgitant fraction. A comprehensive approach is recommended, in which multiple parameters are evaluated and integrated to form a final determination of MR severity. Additional testing including TEE and cardiac magnetic resonance imaging (CMRI) should be used when the assessment of MR on TTE is not definitive.
See also the Guidelines section for recommendations from major medical organizations for the management of MR.
Imaging Studies
Chest radiography
Evidence of left ventricular (LV) enlargement due to volume overload may be observed (particularly in chronic MR), although pulmonary congestion (eg, increased pulmonary markings) may not be observed until heart failure has developed.
Left atrial enlargement may also be observed in the anteroposterior (AP) view as a double shadow in the right cardiac silhouette and/or straightening of the left cardiac border due to the large left atrial appendage.
Echocardiography
European Society of Cardiology (ESC)/European Association for Cardio-Thoracic Surgery (EACTS) criteria for the definition of severe MR are as follows [1] :
-
Flail leaflet/ruptured papillary muscle/large coaptation defect
-
Very large color flow central jet or eccentric jet adhering, swirling, and reaching the posterior wall of the left atrium
-
Dense/triangular continuous-wave signal of regurgitant jet
-
Large flow convergence zone
ACC/AHA Class I indications for performing transthoracic echocardiography include (1) baseline evaluation for LV size and function, RV and LA size, pulmonary artery pressure, and severity of MR; (2) determining the etiology of MR; (3) annual or semiannual surveillance of LV ejection fraction and end-systolic dimension in asymptomatic patients with moderate-to-severe MR; (4) evaluation of the mitral valve apparatus and LV function after a change in signs or symptoms; and (5) evaluation of LV size and function and mitral valve hemodynamics in the initial evaluation after MV replacement or repair. [13]
Parameters of severity of MR include the following:
-
Color flow jet width and area
-
Intensity of continuous-wave Doppler signal
-
Pulmonary venous flow contour
-
Peak early mitral inflow velocity
-
Regurgitant orifice area
-
Regurgitation volume
-
Left ventricular and left atrial size
In evaluating the etiology of MR, note that with acute MR, a ruptured chordae tendineae or papillary muscle, a flail valve leaflet, or infective endocarditis may be identified as the etiology. A central color flow jet of MR with a structurally normal mitral valve suggests functional MR.
ACC/AHA Class I indications for performing serial transthoracic echocardiography include the following [13] :
-
Asymptomatic patients with mild MR and no evidence of LV enlargement, LV dysfunction, or pulmonary hypertension can be observed on a yearly basis; serial echocardiography is not indicated.
-
Patients with moderate MR should have an echocardiogram performed yearly.
-
In asymptomatic patients with severe MR, echocardiography and clinical evaluation should be done every 6-12 months to assess symptoms and development of LV dysfunction.
ACC/AHA Class I indications for performing transesophageal echocardiography are as follows [13] :
-
Assessment of etiology of severe MR in patients for whom surgery is recommended to determine the feasibility of valve repair
-
Evaluation of mitral valve and associated structures in patients for whom transthoracic echocardiography provides nondiagnostic information
Transesophageal echocardiogram demonstrating prolapse of both mitral valve leaflets during systole.
Other Tests
Electrocardiography
Findings on electrocardiography may include the following:
-
Ischemia or infarction in the inferior or posterior leads is present when acute mitral regurgitation (MR) is due to papillary muscle rupture.
-
In chronic mitral valve regurgitation, left ventricular (LV) dilatation and hypertrophy are observed with increased QRS voltage and ST-T wave changes in the lateral precordial leads.
-
Left atrial enlargement in chronic mitral valve regurgitation produces a negative P wave in lead V1, and/or a wide notched P wave in leads II, III, or aVF. Atrial fibrillation may be observed in the late stages.
BNP assessment
Pizarro et al found that in patients with severe asymptomatic mitral regurgitation and normal left ventricular function, levels of brain natriuretic peptide (BNP) have an independent and additive prognostic value. In a prospective study of 269 consecutive patients with severe asymptomatic organic mitral regurgitation and left ventricular ejection fraction above 60%, the receiver-operating characteristics curve yielded an optimal cutoff point of 105 pg/mL of BNP that was able to discriminate patients at higher risk. Pizarro et al recommend considering BNP assessment in the routine clinical workup for risk stratification, which may aid in the selection of patients for early surgery. [14]
Procedures
American College of Cardiology/American Heart Association (ACC/AHA) class I indications for performing cardiac catheterization are as follows [13] :
-
Left ventriculography and hemodynamic measurements are indicated when noninvasive tests are inconclusive regarding severity of mitral regurgitation (MR), left ventricular function, or the need for surgery.
-
Hemodynamic measurements are indicated when pulmonary artery pressure is out of proportion to the severity of MR as assessed by noninvasive testing.
-
Left ventriculography and hemodynamic measurements are indicated when the clinical and noninvasive findings are conflicting regarding severity of MR.
-
Coronary angiography is indicated before mitral valve (MV) repair or MV replacement in patients at risk for coronary artery disease or when the MR is suspected to be ischemic in origin.
-
Transthoracic echocardiogram demonstrating severe mitral regurgitation with heavily calcified mitral valve and prolapse of the posterior leaflet into the left atrium.
-
Transesophageal echocardiogram demonstrating prolapse of both mitral valve leaflets during systole.
-
Transthoracic echocardiogram demonstrating bioprosthetic mitral valve dehiscence with paravalvular regurgitation.
Tables
Stage |
Valve Anatomy |
Valve Hemodynamics* |
Hemodynamic Consequences |
Symptoms |
A: Primary MR |
|
|
|
|
A: Secondary MR |
|
|
|
|
B: Primary MR |
|
|
|
|
B: Secondary MR |
|
|
|
|
C: Primary MR |
|
|
|
|
C: Secondary MR |
|
|
|
|
D: Primary MR |
|
|
|
|
D: Secondary MR |
|
|
|
|
*Several criteria are provided but not all criteria for each category will be present. Severity of mild, moderate, or serve is dependent on data quality and integration with other clinical evidence. †In secondary MR, true ERO is underestimated due to the crescentic shape of the proximal convergence |
||||
CAD = coronary heart disease; ERO = effective regurgitation orifice; HF = heart failure; IE = infective endocarditis; LA = left atrium; LV = left ventricular; LVEF = left ventricular ejection factor; LVESD = left ventricular end-systolic dimension; MR = mitral regurgitation; MV = mitral valve; TTE = transthoracic echocardiography. |
||||
