Mitral regurgitation is one of the most common heart valve conditions worldwide. For much of modern medicine, patients with severe mitral regurgitation had relatively few treatment options. If the valve leaked badly enough to weaken the heart or leave someone short of breath during everyday activities, surgery was often the only way to repair or replace it.
Surgery can work very well, but not every patient can safely undergo an operation. Age, reduced heart function, kidney disease, and previous heart procedures can all increase surgical risk. Interventional cardiologist Konstantinos Marmagkiolis, MD, has practiced during a period when that treatment gap has narrowed, as transcatheter edge-to-edge repair has moved from an experimental procedure to an established option for selected patients.
Transcatheter edge-to-edge repair, also called TEER, treats a leaking mitral valve using a catheter inserted via a vein in the leg. The physician guides the catheter to the heart and places one or more small devices that bring the mitral valve leaflets together at the point where blood is leaking backward. The valve can still open and close around the device, while regurgitation decreases.
The procedure doesn't require opening the chest or stopping the heart, and many patients can return home within a short time.
Two Different Diseases Wearing the Same Name
One of the biggest changes in mitral valve care has been a better understanding of why the valve leaks in the first place. Physicians now distinguish between two main forms of mitral regurgitation: primary and secondary.
Primary, or degenerative, mitral regurgitation results from a problem with the valve itself. A leaflet may become stretched, a supporting chord may rupture, or part of the valve may prolapse backward into the left atrium. The valve is damaged, while the left ventricle may otherwise function normally.
Secondary, or functional, mitral regurgitation develops for a different reason. The valve leaflets may remain structurally normal, but a weakened or enlarged left ventricle can alter the valve's shape enough that the leaflets no longer meet properly. In these patients, the leaking valve is closely tied to the underlying heart failure.
That distinction guides treatment decisions. Surgical repair remains the preferred approach for many patients with primary mitral regurgitation who can safely undergo an operation, particularly when surgeons expect to achieve a durable repair.
TEER has become especially important for patients with secondary mitral regurgitation. Many of these patients already have significant heart failure and may face greater risks from surgery, creating a need for less invasive treatment options.
The Evidence That Changed the Conversation
TEER didn't become part of routine care overnight. Two major trials involving patients with secondary mitral regurgitation produced very different results, prompting physicians to look more closely at which patients actually benefit from the procedure.
The COAPT trial found that adding edge-to-edge repair to guideline-directed medical therapy reduced heart failure hospitalizations and deaths, with benefits that persisted for 5 years of follow-up. The MITRA-FR trial, however, did not find the same benefit.
The differences between the studies helped physicians better understand the relationship between the severity of the valve leak and the condition of the heart. Patients in COAPT generally had significant regurgitation compared with the size of their left ventricles. Patients in the MITRA-FR group tended to have much larger ventricles with less severe regurgitation, relative to ventricular size.
In practical terms, the valve leak played a larger role in the first group. Treating it would make a meaningful difference. In patients whose ventricles had already become severely enlarged and weakened, closing the leak didn't produce the same benefit.
That relationship now plays an important role in matching therapy to valve anatomy and determining which patients are likely to benefit from TEER.
More recent trials have added to that evidence. RESHAPE-HF2 enrolled 505 symptomatic patients with heart failure and significant functional mitral regurgitation. Researchers found that TEER combined with maximally tolerated medical therapy reduced the combined rate of heart failure hospitalization and cardiovascular death, with a rate ratio of 0.64 over two years.
Patients who received TEER also reported greater improvements in symptoms, with symptom scores improving by roughly eleven points more than in the medical therapy group. The trial did not show a reduction in all-cause mortality, an important point for physicians to discuss when explaining what patients can realistically expect from the procedure.
MATTERHORN approached the question from another direction by comparing TEER directly with surgery in 208 patients with heart failure and secondary mitral regurgitation. After one year, the transcatheter approach was noninferior to surgery for the study's composite endpoint of death, heart failure hospitalization, reintervention, assist device implantation, and stroke. The rates were 16.7 percent for TEER and 22.5 percent for surgery.
The safety findings also favored the transcatheter approach. Major adverse events occurred in 14.9 percent of patients who underwent TEER compared with 54.8 percent of those who underwent surgery, while the average hospital stay was four days compared with twelve.
How Device Design Has Changed TEER
The devices used for TEER have also evolved. Earlier clips were available in fewer configurations and required the operator to capture both leaflets simultaneously, limiting treatment options for certain valve anatomies.
Newer systems offer different clip widths and lengths, giving physicians more control over how they capture leaflets. The PASCAL system also includes a central spacer that fills part of the opening between the leaflets and distributes pressure across the valve. That design can be useful in valves with larger gaps or restricted leaflet movement.
The CLASP IID trial compared the PASCAL system with the MitraClip system in patients with degenerative mitral regurgitation and found no meaningful difference in one-year outcomes between the two devices. Having multiple device options allows physicians to consider the specific characteristics of each patient's valve rather than relying on the same approach in every case. That flexibility has helped expand the role of less invasive structural heart care.
Imaging has advanced alongside the devices. Physicians rely heavily on echocardiography during TEER, and three-dimensional transesophageal echocardiography allows the team to visualize the valve, guide device placement, and assess the amount of residual regurgitation in real time.
Because the procedure depends so heavily on imaging, the echocardiographer plays an important role alongside the interventional cardiologist. The team needs a clear view of the valve before, during, and after device placement to achieve the best possible result.
The Practical Decisions Behind the Procedure
TEER can offer significant benefits, but physicians must weigh its limitations.
Bringing the valve leaflets closer together reduces regurgitation, but it can also make the opening smaller. If the physician reduces the leak too aggressively, the patient can develop mitral stenosis or an elevated pressure gradient across the valve. Residual regurgitation also matters. Patients who leave the procedure with moderate or worse leakage tend to have less favorable outcomes than those whose regurgitation improves to mild.
Durability remains another consideration. Surgical repair has decades of follow-up, while TEER has a shorter track record. Some patients may eventually need another procedure, and a previously clipped valve can make later surgery or transcatheter mitral valve replacement more complicated.
The importance of that issue depends heavily on the patient. For an older patient with advanced heart failure who faces substantial surgical risk, the immediate benefits of a less invasive procedure may carry more weight. For a younger patient with degenerative valve disease who can safely undergo surgery, long-term durability may play a much larger role in the decision.
Anatomy can also determine whether TEER is appropriate in the first place. Severe leaflet calcification, very short leaflets, large gaps, rheumatic valve disease, and certain clefts or perforations can make the procedure more difficult or unsuitable. A detailed imaging review helps the heart team determine whether the valve can accommodate a device and whether TEER is likely to produce a meaningful improvement.
Patients evaluated through programs offering coordinated heart and vascular care can also benefit from having multiple treatment options considered together. In some cases, the best approach may be TEER. In others, guideline-directed medical therapy, cardiac resynchronization, or surgical repair may offer a better fit.
What Comes Next
Researchers continue to study where TEER fits in the treatment of mitral regurgitation and whether physicians should intervene earlier in the course of heart failure. They are also examining how TEER should be used alongside increasingly effective medical treatments and whether the same approach can benefit patients with severe tricuspid regurgitation.
Some early studies suggest that treating both the mitral and tricuspid valves as part of a single treatment strategy may be feasible in carefully selected patients.
Transcatheter mitral valve replacement is also continuing to develop. As those technologies improve, physicians will have another option to consider alongside repair. The choice between repair and replacement will likely depend on the patient's valve anatomy, surgical risk, heart function, and overall health.
For clinicians such as Konstantinos Marmagkiolis, MD, TEER has expanded the options available to patients who once had few reasonable choices. Patients who might previously have faced high-risk surgery or medical treatment alone can now be evaluated for a catheter-based procedure that avoids an open-chest operation and can allow for a much shorter recovery.
The challenge now is less about whether TEER can treat mitral regurgitation and more about determining when it offers the right solution for the patient sitting before the heart team.
