Successful repair with percutaneous or open repair requires a skilled team that includes the following:

• Cardiac surgeon
• Interventional cardiologist (percutaneous technique)
• Perfusionist
• Anesthesia team
• Operation room/hybrid room personnel (nursing, scrub techs)
• Skilled ultrasonographer

Before undergoing percutaneous or open mitral valve repair for mitral stenosis, the patient will need a complete workup with labs, imaging, and full history with a physical exam. The patient will need a 2-D cardiac transthoracic echo to evaluate the entire heart to rule out other possible surgical interventions while in the operating room. A transesophageal echo is mandatory prior to scheduling a percutaneous mitral valve balloon valvuloplasty to rule out any left atrial thrombus, the severity of any mitral regurgitation, or any other valve abnormality.

A cardiac structural specialist may be necessary to view the echo. You must review all echo studies and discuss the best approach for your patient not only based on the valve pathology but also on their lung function, pulmonary pressures, body surface area, and cardiac/non-cardiac functional disability. All surgical procedures, whether performed in the hybrid room or operating room, should be performed within a sterile field with all precautions taken to maintain sterility.

Open Mitral Valve Commissurotomy

It has long been considered the gold standard for mitral valve stenosis repair.[6] The surgical outcomes of the percutaneous technique have not been around as long as open or closed techniques; therefore, multiple studies have shown that an open technique yields excellent results. This technique allows the surgeon to have direct visualization of the entire mitral valve. This technique uses cardiopulmonary bypass, whereas the closed technique can avoid going on bypass. Over the years, multiple studies have shown this to be a safe technique with excellent outcomes for open commissurotomy.[7]

Technique

The open technique uses a median sternotomy to gain access to the chest, but a right or left thoracotomy can be used to gain access to the mitral valve. A right thoracotomy incision and femoral cannulation will allow the surgeon to avoid midline sternal incision if there is a history of previous thoracic surgery via a sternotomy. After the chest is opened, the patient is placed on cardiopulmonary bypass with cannulation of the aorta, bicaval venous cannulation, and administration of cardioplegia. Once the cardiopulmonary bypass is established, the left atrium can be opened. Exposure of the mitral valve can be performed in many ways; there are three possible approaches: Interatrial groove approach, transatrial oblique approach, or transatrial longitudinal septal approach. Each approach to the mitral valve has its own pros and cons. Once the mitral valve is reached and properly exposed, two polypropylene sutures are placed to provide slight traction upward toward the superior left atrium. If sutures are not placed, nerve hooks can provide upward traction. This maneuver allows exposure of the mitral leaflets, which in return shows the line of mitral commissural fusion.

Once the line of mitral fusion is noted, one should try to examine the chords and papillary muscles through the mitral orifice. One should look for any evidence of calcification, shortening, or fusion to the subvalvular apparatus. A right-angle clamp can then be passed through the orifice and placed gently below the fused mitral commissures. The clamp can then be opened slightly so that a # 15 blade scalpel or # 11 blade scalpel can be used to cut on the commissures without damaging the structures below. With the clamp open, the first incision is made 5 mm from the annulus on top of the clamp, cutting downward into the fused chords and papillary muscle, this incision is extended toward the mitral orifice. If the incision does not enter the head of the papillary muscle, this can cause division of the papillary muscle, and repair or reimplantation would be necessary. The commissurotomy can not be overextended, or this may cause mitral valve incompetence. If valve incompetence is caused, then an annuloplasty of the ring or commissuroplasty may need to be performed. Once the commissurotomy is completed, the patient can be taken off bypass, and a post-procedure transesophageal echo can be obtained. 

Closed Mitral Valve Commissurotomy

It was very popular for mitral valve stenosis repair since the 1920s. It has been widely used throughout the world and continues to be used in developing countries. Closed mitral valve commissurotomy is rarely performed in the United States due to the success of the open technique with cardiopulmonary bypass. This technique remains useful in select subgroups of patients even though there is no direct visualization of the mitral valve. Closed mitral commissurotomy remains a predominant technique in developing countries due to the low cost and the simplicity of the surgery compared to the open technique. The closed technique can now be performed through a small thoracotomy incision with port placement via guidance with transesophageal echo.[8]

Technique

A closed mitral valve commissurotomy is performed either through a left posterolateral or anterolateral thoracotomy at the level of the 5th rib. The lung is then retracted in the posteroinferior position. An incision is made parallel to the phrenic nerve, and the pericardium is opened then traction sutures are placed. The left atrial appendage is then excluded with a side biting clamp, and a left atrial polypropylene purse-string suture is placed. A second purse-string suture is placed with pledgets at the apex of the left ventricle.

The left atrial appendage is then opened, and the index finger is placed into the left atrium; the mitral valve is palpated to feel for any calcification, stenosis, or insufficiency. Prior to placing a finger into the left atrium, thrombus should be palpated; if the clot is palpated, then it should be excluded using the clamp. The thrombus can then be removed after exclusion with the clamp. If the thrombus can not be removed after the clamp is applied, this is a major indication to abort the closed technique and convert to an open technique with the initiation of cardiopulmonary bypass. When the finger is introduced into the left atrial appendage, it should not be placed for more than 2 to 3 cardiac cycles. If placed for longer than 2 to 3 cardiac cycles, this can produce dysrhythmia, which can lead to cardiac arrest. Once the index finger is placed into the left atrium, the heart can be elevated by bringing the apex of the left ventricle into view. A #11 blade scalpel is used to make a small ventriculotomy inside the purse-string suture, which was placed earlier in operation. Once the ventriculotomy is made, Hagar dilators are used until the Tubb valvulotome can be passed through the left ventricle passing through the mitral valve into the left atrium.

The Tubb valvulotome is opened quickly to an exact preset measurement of 3.5 to 4.5 cm, closed quickly, and then removed from the heart. After the finger is removed from the left ventricle, the purse string is tied down over pledgets. When passing the Tubb valvulotome, it must not be opened prematurely as this can cause damage to the mitral subvalvular apparatus and result in mitral insufficiency. If the Tubb dilator is not able to fully dilate the mitral valve, this is an indication for an open commissurotomy. Any time a patient is undergoing closed commissurotomy, the patient should have cardiopulmonary bypass at the bedside in the OR in case it is urgently needed. Once the procedure is completed, as all post-op valve procedures are done, a cardiac echo is needed to measure the valve area, pressures of the left atrium/pulmonary pressures, and the degree of mitral regurgitation that was caused.[9] Studies have shown excellent valve area that is gained with the added benefit of no cardiopulmonary bypass when using the closed technique.[10]

Percutaneous Mitral Valve Commissurotomy

The percutaneous mitral valve technique is the standard treatment used to treat MS patients with favorable valve anatomy. The technique was first introduced in the mid-1980s. Today it is now the standard first-line treatment for patients that meet the criteria for balloon dilation of the valve. Patient selection is very important when deciding which option to offer patients for repair, but one must always take into account the valve anatomy and experience of the surgical team. The percutaneous technique offers excellent 15-year outcomes when used in younger patients that had more valve area prior to intervention.[11] 

The percutaneous technique had multiple options for balloon dilation of the mitral valve. In the past, a double-balloon technique has been used, but over the years, we have trended to the use of an Inoue balloon. The Inoue balloon is easier to use from a technical standpoint, and it has a lower complication rate compared to the double-balloon technique.[12] When patients are done with their percutaneous intervention, the majority have immediate hemodynamic benefits as the procedure offers an increase in the overall mitral valve area and a decrease in the overall mitral valve gradient. After the percutaneous intervention, the majority of patients that presented with an NYHA class 3 when reexamined at follow up appointments had an NYHA 2 classification. The percutaneous technique acts very similarly to the open technique in that the commissures are split open by opening the balloon inside in the stenotic valve. 

• Pregnancy can often unveil a previously compensated MS. The pregnancy often increases the cardiac output and causes associated tachycardia, which increases during the second trimester. This major change in fluid status and worsening of the mitral valve stenosis can lead to heart failure symptoms in pregnant patients; this is why they should be treated with percutaneous mitral valve valvuloplasty.[13] The goal of mitral valve intervention is not for full repair but to overall improve the hemodynamic status of the patient.[14]

Technique

The groin is prepped/draped in the usual sterile fashion, and the femoral vein is accessed under ultrasound guidance. After access to the vein, the sheath and wire are placed with the placement of the wire into the right atrium. Transseptal catheterization into the left atrium is the most important step in the procedure. The Inoue balloon is then placed through the septum into the left atrium. The balloon itself has three different parts, all with different elastic strengths that can be inflated consecutively. The balloon ranges in size from 24 to 30 mm. The choice of balloon size is based on the patient's current height and body surface area or maximal size of the inter commissural distance.[15] 

After the balloon is in position across the valve, the balloon is inflated under echocardiographic guidance. The balloon is inflated in a sequential fashion, starting with the smallest size of the balloon. Once the valve has been dilated, the balloon is withdrawn into the left atrium, and the valve is checked from any increase in the valve area and any degree of mitral regurgitation.[16] 

If the valve area is not sufficient the balloon can be readvanced with further dilation of the valve. Once the valve has been dilated and the echo shows desirable results such as a mitral valve area of more than 1 cm^2/m^2 of body surface area, completely opening of at least one of the commissures, or an increase in the regurgitation across the valve, the procedure can be completed. The echo should be performed again in several days due to a slight valve area loss that occurs over the next 24 to 36 hours. This technique has shown through multiple studies that it provides excellent improvement of valve area, decrease in left atrial pressures, improves coronary flow, and can increase cardiac index.[17]

The complications associated with mitral valve repair are very similar in open repair or transcatheter percutaneous repair. Mortality of mitral valve repair in recent studies has shown zero deaths related to repair and overall less than 3% complication rate. The following are some important complications:

• Catheter-related complications to access the site, such as hematoma, arteriotomy, dissection, arteriovenous fistula
• Stroke
• Myocardial infarction due damage or irritation to the left coronary artery
• Perioperative bleeding and resulting blood products transfusion-related complications
• Mitral regurgitation
• Pericardial tamponade
• Arrhythmias and heart blocks
• Heart failure
• Drug reactions
• Surgical site infections
• Sepsis
• Pulmonary complications, such as pneumothorax, pneumonia, embolisms
• Renal failure due to concomitant use of contrast dye

Mitral stenosis is a significant disease process that affects millions of people worldwide. With more safe options for treatment and better overall operative rates with newer technology, we can now help treat patients with percutaneous intervention in those who have suitable valve anatomy. Untreated MS causes the patient's morbidity and mortality, especially when combined with other cardiac or pulmonary disease processes. When the finding of MS arises, it should be addressed if surgical intervention is warranted. We need to continue to monitor outcomes of both open vs. percutaneous mitral valve repairs to continue to gain knowledge of what changes we need to make to help guide the future of rheumatic mitral heart disease.

Mitral valve stenosis is a disease process usually caused by rheumatic fever. Mitral valve commissurotomy is the procedure of choice for the treatment of mitral valve stenosis. This entire disease process should be managed with a multidisciplinary team from the time the stenotic valve is diagnosed and, most importantly, throughout the entire surgical management. As mitral valve surgery advances, it is essential to have interprofessional teams that are close in communication with the management of patients to help advance the field and decrease morbidity and mortality.

An interprofessional team should include an anesthesia team, cardiologists, cardio-thoracic surgeons, and cardiac intensivists. Preoperative echocardiographic evaluation of the mitral valve requires coordination between the ultrasound sonographer and the cardiac surgery team. The intraoperative repair of the valve requires closed-loop communication between the cardiac surgeon, anesthesiologist, cardiologist, circulating nurse, and OR techs.

Nurses, technicians, and physicians of multiple specialties all play a major role in monitoring the patient. These roles require excellent interprofessional communication between all teams involved. The entire operative course from pre-operative, intra-operative, and post-operative management of the patient requires a skilled team.