Minimally Invasive Mitral Valve Repair (Mini MVR)

There are two main conditions that can affect a mitral valve, mitral stenosis (MS) or mitral regurgitation (MR). These conditions are usually diagnosed by your internist by the detection of a heart murmur and followed by your cardiologist by periodic echocardiograms. Once these conditions become severe and/or symptomatic, in almost all cases surgery should be performed.

When mitral stenosis or regurgitation is severe and/or symptomatic, blood that normally drains from the lungs into the heart cannot drain effectively.  This causes backup and congestion in the lungs which the patient experiences as shortness of breath. This type of congestive heart failure can creep up on a patient with little warning and subtle symptoms such that the patient often attributes their breathlessness and fatigue as “just getting old” or “needing to lose a few pounds.”  There are definite echocardiographic criteria for establishing a diagnosis of severe mitral stenosis or regurgitation. Best treatment algorithms have been defined by the American Heart Association/ American College of Cardiology.

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AHA/ACC 2014 Guidelines for the Management of Patients with Severe and Moderately Severe Mitral Regurgitation

Mitral Regurgitation

AHA/ACC 2014 Guidelines for the Management of Patients with Severe and Moderately Severe Mitral Stenosis:

Mitral Stenosis

In most cases once a mitral valve is severely regurgitant or stenotic and/or symptomatic, best treatment indicates mitral valve repair or replacement.

What’s the most important thing to achieve in mitral valve surgery?

The most important thing to be achieved in mitral valve surgery (except in the case of rheumatic mitral stenosis where a chordal sparing replacement is almost always performed) is a successful and durable mitral valve repair. We feel all mitral patients should be evaluated by an experienced valve surgeon as that should maximally enhance their chances of achieving a durable mitral valve repair.  In most cases, earlier treatment before irreversible damage to the heart and lungs are sustained is advisable. Earlier treatment also improves the chances of achieving a successful mitral valve repair. Long term studies have shown that a successful mitral valve repair can lead to improved long term survival compared with patients undergoing mitral valve replacement.

Long Term Survival Mitral Valve Repair vs. Replacement patients:

Mitral Valve Repair vs. Replacement patients

What causes mitral regurgitation?

The mitral valve is composed of 2 leaflets configured somewhat like 2 saloon doors, an anterior and a posterior leaflet. The surrounding frame around these 2 leaflets is called the mitral valve annulus and the leaflets are attached to the inner surface of the left ventricle by tiny strings resembling parachute chords called chordae. If one or several of these chordae rip or tear or become abnormally lengthened or shortened, lack of contact of the surfaces of the anterior and posterior leaflets will result. Since the mitral valve is only competent when both anterior and posterior leaflets have appropriate contact, chordae that are torn, ripped, lengthened, or shortened can lead to mitral regurgitation. Another common problem is generalized dilation of the frame of the mitral valve, the mitral valve annulus.  As heart valves leak, excessive blood backs up into the heart chambers which causes progressively dilation and enlargement of the heart.  As a result, the annulus of the mitral valve dilates; the 2 leaflets of the mitral valve are unable to properly contact each other resulting in increased leakage and progressive dilation over time.  If untreated long enough, mitral regurgitation can lead to severe dilation of the heart, congestive heart failure, and a shortened lifespan.

Minimally Invasive Mitral Valve Repair (Mini MVR)

Traditional mitral valve surgery is performed using a 10 – 12 inch incision dividing the entire breastbone in the midline. Minimally invasive mitral surgery can now be performed through only a 3 inch incision either on the right side of the chest (under the breast where the incision can be well hidden) or in the midline.

Mini MVR has definite benefits for the patient not only in cosmetic appearance but also in regards to reduced pain, reduced blood loss and need for transfusions and better breathing ability after surgery with no apparent downside.

The Cleveland Clinic published a study comparing the results of Mini MVR vs. standard full sternotomy MVR:

Objective: Less invasive approaches to mitral valve surgery are increasingly used for improved cosmesis; however, few studies have investigated their effect on outcome. We sought to compare these minimally invasive approaches fairly with conventional full sternotomy by using propensity-matching methods.

Methods: From January 1995 to January 2004, 2124 patients underwent isolated mitral valve surgery through a minimally invasive approach and 1047 underwent isolated mitral valve surgery through a conventional sternotomy. Because there were important differences in patient characteristics, a propensity score based on 42 factors was used to obtain 590 well-matched patient pairs (56% of cases).

Results: In-hospital mortality was similar for propensity-matched patients: 0.17 %( 1/590) for those undergoing minimally invasive surgery and 0.85 %( 5/590) for those undergoing conventional surgery (p = .2). Occurrences of stroke (P = .8), renal failure (P>.9), myocardial infarction (P = .7), and infection (P = .8) were also similar. However, 24-hour mediastinal drainage was less after minimally invasive surgery (median, 250 vs. 350 mL; P<.0001), and fewer patients received transfusions (30% vs. 37%, P = .01). More patients undergoing minimally invasive surgery were extubated in the operating room (18% vs. 5.7%, P<.0001), and postoperative forced expiratory volume in 1 second was higher. Early after operation, pain scores were lower (P<.0001) after minimally invasive surgery.

Conclusion: Within that portion of the spectrum of mitral valve surgery in which propensity matching was possible, minimally invasive mitral valve surgery had cosmetic, blood product use, respiratory, and pain advantages over conventional surgery, and no apparent detriments. Mortality and morbidity for robotic and percutaneous procedures should be compared with these minimally invasive outcomes. (J Thorac Cardiovasc Surg 2010;  139:926-32).

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A Mini MVR patient 2 weeks postop.

Dr. Lee's Mini MVR patient 2 weeks postop