Mitral Regurgitation: Causes, Diagnosis, and Intervention

Mitral regurgitation (MR), also known as mitral valve insufficiency, is a common valvular heart condition where the mitral valve does not close properly, allowing blood to leak backwards into the left atrium. This backflow increases the workload on the heart and can lead to symptoms such as shortness of breath, fatigue, palpitations, and, in severe cases, heart failure. MR affects millions worldwide and can range from mild and asymptomatic to severe and life-threatening.

Early and accurate diagnosis is critical to preventing progression and preserving heart function. Modern evaluation relies heavily on advanced imaging—such as transthoracic echocardiography, 3D transesophageal echocardiography, cardiac CT, and cardiac MRI—to assess valve anatomy, quantify regurgitation, and guide decision-making.

Once the mechanism and severity of MR are established, treatment planning can begin. Options range from medical management and minimally invasive repair techniques like transcatheter edge-to-edge repair (TEER) to advanced interventions such as transcatheter mitral valve replacement (TMVR) for patients unsuitable for surgery. By integrating imaging findings with patient-specific factors, clinicians can tailor interventions to achieve the best possible outcomes.

What Causes Mitral Regurgitation?

Mitral regurgitation arises from various underlying mechanisms, commonly classified as:

• Primary (Degenerative) MR: Structural abnormalities of the mitral valve apparatus, including mitral valve prolapse (MVP), myxomatous degeneration, or fibroelastic deficiency, which cause leaflet mal-coaptation.
• Secondary (Functional) MR: The mitral valve leaflets are structurally normal but fail to close effectively due to left ventricular dilation or remodelling, often secondary to ischemic heart disease or cardiomyopathy.
• Other causes include rheumatic heart disease, infective endocarditis, mitral annular calcification, and ischemic damage following myocardial infarction.

Each cause requires specific clinical considerations for diagnosis and management.

 

Symptoms and Disease Progression

Symptoms of mitral regurgitation can develop gradually and may include:

• Shortness of breath, especially during exertion or when lying flat 
• Fatigue and decreased exercise tolerance 
• Palpitations or irregular heartbeat due to atrial fibrillation 
• Swelling in legs or abdomen (in advanced cases) 

Mild MR can remain asymptomatic for years but may progress to cause volume overload, left atrial enlargement, pulmonary hypertension, and heart failure if untreated. Understanding disease progression through regular follow-up imaging is key to timely intervention.

 

Diagnostic Coding and Clinical Documentation

Accurate clinical documentation supports appropriate patient care and reimbursement. Common ICD-10 codes related to mitral regurgitation include:

• I34.0 – Nonrheumatic mitral valve insufficiency
• I34.1 – Nonrheumatic mitral valve prolapse 
• I05.1 – Rheumatic mitral insufficiency 
• Z95.2 – Presence of prosthetic heart valve (post mitral valve repair or replacement)

Documentation should reflect MR severity (e.g., “trace,” “mild,” “moderate”) to guide monitoring and treatment planning.
 

Differentiating Mitral Valve Prolapse and Mitral Regurgitation

Mitral valve prolapse (MVP) is a frequent cause of MR but does not always lead to significant regurgitation. MVP is characterized by leaflet displacement into the left atrium during systole and is often benign. However, progression to MR can occur, particularly if chordae tendineae rupture or leaflet thickening develops.

Distinguishing MVP from MR is essential for patient management. Echocardiography remains the diagnostic standard for MVP, with advanced CT imaging valuable in complex anatomy or pre-procedural planning.
 

How Imaging Is Used to Diagnose Mitral Regurgitation

Timely and accurate diagnosis of mitral regurgitation (MR) is essential for determining the best course of treatment and long-term management. Noninvasive imaging tools—particularly echocardiography, transesophageal echo, and 4D flow MRI—form the foundation of evaluation. These tools provide insight into valve anatomy, regurgitant flow, and functional impact on the heart.

 

Echocardiographic Evaluation

A mitral regurgitation echo is often the first step in diagnosis. This test evaluates regurgitant volume, jet direction, chamber size, and overall cardiac function. Early-stage cases like trace mitral valve regurgitation or mild to moderate mitral valve regurgitation are typically found during routine echocardiography.

For more precise visualization, TEE—especially 3D TEE mitral valve imaging—offers enhanced resolution. This includes the bicommissural view TEE, short axis mitral valve plane, and the ability to assess specific leaflet segments such as A1, A2, A3. These views help differentiate between types of regurgitation and identify causes such as mitral valve prolapse or leaflet restriction.

Other echocardiographic parameters like mitral valve area pressure half-time, DVI mitral valve, and flow reversal are used to quantify severity and guide next steps. These tools are also helpful in identifying conditions like nonrheumatic mitral valve insufficiency and mild mitral valve regurgitation—often asymptomatic but clinically significant over time.

For advanced echo analysis, visit our echocardiography software page.

 

4D Flow MRI in Functional Assessment

When TTE and TEE findings are inconclusive or complex, 4D flow MRI plays a critical role. This technique captures time-resolved, three-dimensional data that maps the path and volume of blood through the mitral orifice.

It’s particularly useful in cases of:

• Moderate to severe mitral regurgitation
• Concomitant pulmonary hypertension
• Mitral valve regurgitation and mitral valve prolapse overlap
• Situations where mild mitral valve regurgitation and exercise cause symptoms

Our MR 4D Flow solution provides objective flow quantification, assisting in the staging of disease and tracking changes over time.

Learn more on the MR 4D Flow product page.

Supporting Diagnosis with Clinical Criteria

The integration of imaging with clinical findings and guidelines is critical. This includes:

• Recognizing when trace mitral valve regurgitation is normal
• Understanding symptoms of mitral valve prolapse
• Identifying distinguishing features of mitral valve prolapse vs mitral regurgitation
• Adhering to ASE mitral stenosis and ESC diagnostic criteria
• Recognizing common co-pathologies like mild tricuspid valve regurgitation and mitral valve regurgitation

Planning a complex case? Explore 3mensio mitral valve for procedural imaging and planning.

Imaging for Repair Planning

When intervention is considered—whether surgical or transcatheter—imaging becomes even more critical. TEE MV repair guidance is standard for robotic mitral valve repair and intraoperative assessment. Interventional tools like MitraClip echo and MitraClip TEE help optimize device placement and assess for residual jets. Segmental imaging aids in approaches like Alfieri stitch mitral valve or commissuroplasty valve procedures. Imaging also plays a key role in identifying who is a candidate for mitral valve clip based on anatomy and regurgitation severity.

 

Mitral Valve Repair Procedure Options

TMVr offers multiple pathways to address MR and restore valve competency:

   1. Leaflet repair: Techniques such as the Alfieri stitch mitral valve technique and MitraClip operation bring mitral leaflets closer together.
   2. Chordal repair: Neochord procedure and Harpoon mitral valve systems allow for minimally invasive chordal restoration.
   3. Annular reshaping: Cardioband and other annuloplasty devices reshape the annulus to improve leaflet coaptation.

These repair strategies are increasingly replacing traditional surgery due to their ability to repair the mitral valve without surgery in select patients.

 

Transcatheter Edge-to-Edge Repair (TEER)

TEER, for example the MitraClip procedure, is a catheter-based technique used for moderate to severe MR in patients unsuitable for open-heart surgery. It approximates the mitral leaflets with a clip to reduce regurgitation. This technique can be guided by advanced imaging such as TEE MV repair, fluoroscopy, and CT.

Popular TEER Devices Include:

• MitraClip (Abbott): The gold standard with multiple generations (NT, XT, G4).
• PASCAL (Edwards Lifesciences): Offers independent leaflet capture and broader tissue grasping, ideal for complex anatomies.
• MyClip (Meril) A newer entrant designed for transcatheter edge-to-edge repair, emphazising simplified delivery, reduced procedural time, and adaptability to varied mitral anatomies.

 Key Benefits of TEER Include:

• Non-invasive mitral valve repair option
• Shorter recovery times
• Effective in both primary and secondary MR

 

Pre-Procedural Imaging & 3mensio

Detailed imaging and planning are crucial before performing any mitral valve procedure. Advanced software such as 3mensio supports:

• 3D valve modelling
• Precise annular and leaflet measurements
• Virtual device simulation
• CT fusion imaging

Such planning enhances the precision of TEER and TMVr procedures and minimizes complications.

 

Annular Repair in Mitral Regurgitation

In cases of secondary MR, the mitral annulus often dilates, contributing to MR progression. While TEER does not include annuloplasty, combining it with devices like Cardioband can provide annular reshaping. Other devices include:

• Millipede IRIS
• Carillon Mitral Contour System (indirect annuloplasty via coronary sinus)

 

Mitral Valve Replacement (MVR) and TMVR

When repair is not feasible, transcatheter mitral valve replacement (TMVR) becomes necessary. Devices like the Tendyne valve (Abbott) offer a fully implantable replacement system. TMVR is suitable for patients with severe MR, mitral annular calcification (MAC), and those who fail previous repair attempts.

Conditions Often Leading to TMVR Include:

• Advanced mitral valve regurgitation
• Severe mitral stenosis
• Extensive MAC

TMVR is more complex than TEER but provides a definitive solution when native leaflet function cannot be restored.

 

What Is TMVR?

TMVR is a catheter-based intervention where a bioprosthetic mitral valve replacement is implanted to replace the diseased native valve. This procedure can be performed via two primary approaches:

• Transapical access: Through a small incision in the chest wall.
• Transseptal access: Through the femoral vein and across the interatrial septum.

Unlike traditional MVR heart surgeries, TMVR eliminates the need for open-heart procedures, significantly reducing trauma and recovery time.

 

When Is TMVR Considered Over MVR Surgery?

TMVR is often the preferred choice in situations where conventional MVR replacement or mitral valve repair is not feasible:

• Failed TEER or Recurrent MR: If Transcatheter Edge-to-Edge Repair (TEER) fails, TMVR can replace the entire valve.
• Complex Valve Anatomy: TMVR is favored for conditions like calcification, leaflet prolapse, or severe restriction.
• Severe Mitral Annular Calcification (MAC): TMVR valves can anchor securely even in heavily calcified tissue.
• Mixed Mitral Valve Disease: In cases involving both stenosis and regurgitation, TMVR offers full valve restoration.
• Enlarged Mitral Annulus: When the mitral ring is too wide for clipping procedures, TMVR provides a predictable outcome.
• High Surgical Risk or Inoperability: Patients unfit for open-heart MVR surgery due to age or comorbidities are ideal candidates for TMVR.

 

Access Routes for TMVR

Transapical Approach

• Involves a direct path to the mitral valve through the chest wall and left ventricle apex.
• Offers precise device control.
• More invasive; requires general anesthesia.

Transseptal Approach

• Less invasive; uses the femoral vein.
• Catheter crosses into the left atrium via the interatrial septum.
• Preferred for newer devices and faster recovery.

Both techniques are chosen based on patient anatomy, device compatibility, and operator expertise.

TMVR in Complex Anatomical Scenarios

TMVR has shown significant promise in patients with challenging anatomies:

• MAC (Mitral Annular Calcification): The calcified ring provides a stable docking site.
• Valve-in-Valve (ViV): For patients with failing bioprosthetic mitral valves, TMVR allows insertion of a new valve without removing the old one.
• Valve-in-Ring (ViRing): TMVR is used to place a new valve inside a previously implanted annuloplasty ring.

These options allow TMVR to replace failing devices without undergoing repeat MVR heart surgery.

 

TMVR Devices and Valve Systems

Several innovative MVR replacement devices are now available or in development:

• Tendyne™ (Abbott) – Transapical delivery; repositionable and tethered.
• Intrepid™ (Medtronic) – Dual stent design, suitable for both transapical and transseptal routes.
• Sapien M3™ (Edwards Lifesciences) – Transseptal approach using a docking system with a balloon-expandable valve.
• AltaValve™ (4C Medical) – Supra-annular design, minimizes contact with native valve and avoids LVOT obstruction.

In addition to TMVR-specific systems, surgical mitral valves like the Epic™ Mitral Valve (Abbott) and On-X Mitral Valve (Artivion) are critical in conventional MVR surgery and serve as viable targets in Valve-in-Valve TMVR cases.

If you’re researching valve types for your condition, comparing the Epic mitral valve with an On-X mitral valve may help you and your cardiologist choose the right prosthesis for your long-term needs.

 

Role of Imaging in TMVR Planning

Advanced imaging is essential to assess anatomy and ensure a safe procedure:

1. Cardiac CT: 

• Measures mitral annulus size
• Evaluates neo-LVOT area to prevent outflow obstruction
• Identifies calcium distribution 

2. 3D TEE (Transesophageal Echocardiography): Provides real-time intraoperative visualization.
3. Fusion Imaging: Combines fluoroscopy with CT for enhanced navigation.

Planning TMVR with 3mensio Software

3mensio Structural Heart streamlines TMVR planning by offering:

• Accurate annular sizing
• Neo-LVOT area prediction
• Assessment of annular and sub-annular calcification
• Simulation of transapical or transseptal access paths

This enables precise device selection, positioning, and risk management—especially in anatomically complex cases.

TMVR Procedure Workflow

• Multidisciplinary Evaluation: Cardiac team reviews patient’s risk and imaging.
• Access: Catheterization via transapical or transseptal route.
• Valve Deployment: Guided by TEE and fluoroscopy.
• Assessment: Immediate evaluation for leaks, obstruction, and positioning.

 

TMVR Benefits and Limitations

Benefits

• Complete resolution of MR in anatomically complex patients
• Less invasive than open MVR surgery
• Reduced hospital stays and improved quality of life

 

Limitations

• Requires advanced operator training
• Some devices not widely approved yet
• Risk of LVOT obstruction, paravalvular leak, and embolization
• Ongoing need for anticoagulation in most cases

 

TMVR vs. TMVr: Making the Right Choice

While TEER is an effective repair method for many, TMVR is preferred when:

• The valve anatomy is not ideal for clipping
• There’s severe calcification or annular dilation
• Previous TEER has failed
• Complete MVR replacement is required
• Choosing between TMVR and TEER depends on imaging findings, patient comorbidities, and clinical judgment.

 

Health Risks and Post-Procedural Care

As with any mitral valve repair procedure, there are associated risks:

• Residual MR or recurrence
• Mitral stenosis
• Access site complications
• Stroke or TIA
• Endocarditis (e.g., mitral endokarditis)

Patients should closely follow post mitral valve procedure care guidelines and monitor for signs of complications. Imaging follow-up and routine assessments ensure long-term durability of the repair.

 

Conclusion

Mitral regurgitation is a complex condition requiring precise diagnosis, tailored intervention, and multidisciplinary expertise to achieve optimal outcomes. Advances in imaging, device technology, and transcatheter techniques such as Transcatheter Mitral Valve repair and Transcatheter Mitral Valve Replacement have expanded treatment options for patients previously deemed inoperable. From established devices like MitraClip to newer entrants such as PASCAL and MyClip, clinicians now have a growing toolkit to address a wide range of anatomical and clinical scenarios. Careful patient selection, detailed procedural planning, and ongoing post-procedural monitoring remain essential to ensure long-term success, improve quality of life, and reduce the burden of mitral valve disease.