Continuing Education Activity

Mitral commissurotomy is a surgical procedure that relieves mitral valve stenosis by separating fused commissures of the mitral valve leaflets, thereby improving blood flow from the left atrium to the left ventricle. This technique can be performed using open, closed, or percutaneous approaches, each with distinct advantages and indications based on patient anatomy and clinical circumstances. Successful commissurotomy can significantly enhance patient outcomes by reducing symptoms, improving functional capacity, and decreasing the risk of complications such as atrial fibrillation and heart failure.

Clinicians participating in this course gain a comprehensive understanding of the indications, techniques, and outcomes associated with mitral commissurotomy. They enhance their knowledge of patient selection criteria, perioperative management, and postoperative care strategies. Additionally, the course fosters interprofessional collaboration skills, enabling participants to communicate and coordinate care among diverse healthcare teams effectively. This knowledge empowers clinicians to improve patient-centered care, optimize surgical outcomes, and enhance clinical practice safety and performance.

Objectives:

• Identify the appropriate candidates for mitral commissurotomy based on valve anatomy, comorbidities, and surgical history.

• Differentiate between the various surgical techniques for mitral commissurotomy, including open, closed, and percutaneous approaches.

• Screen patients for potential complications and contraindications associated with mitral commissurotomy, ensuring comprehensive preoperative assessments.

• Coordinate care among multidisciplinary teams to ensure comprehensive postoperative support and rehabilitation for patients.

Introduction

Mitral valve commissurotomy is a surgical procedure designed to relieve mitral stenosis by separating the fused commissures of the mitral valve. This condition, commonly a result of rheumatic heart disease, leads to a narrowing of the mitral valve orifice, impeding blood flow from the left atrium to the left ventricle and resulting in elevated atrial pressures and pulmonary hypertension. Since its initial development in the early 20th century, mitral commissurotomy has evolved from open surgical techniques to percutaneous balloon approaches, offering less invasive options for certain patient populations.

Mitral valve commissurotomy, a procedure indicated primarily for patients with symptomatic mitral stenosis who are unsuitable for valve replacement, remains a key intervention in low-resource settings where rheumatic heart disease is prevalent. The procedure can be performed either through an open surgical approach or percutaneously, with each modality offering distinct advantages depending on valve morphology and patient characteristics. 

Anatomy and Physiology

Mitral Valve Anatomy  

The mitral valve, a vital bicuspid valve, controls blood flow between the left atrium and left ventricle. Comprising 2 leaflets—anterior and posterior—the anterior leaflet, known as the aortic leaflet due to its fibrous continuity with the aortic valve, covers about one-third of the orifice. The broader posterior, or mural, leaflet spans two-thirds of the valve's opening. Both leaflets are anchored by chordae tendineae that attach to the superolateral and inferoseptal papillary muscles, preventing prolapse during ventricular systole.

The right coronary sinus and the left circumflex coronary artery are near the posterior leaflet. During mitral valve procedures, these structures are vulnerable to injury if excessive force is applied or sutures are incorrectly placed. A thorough understanding of this anatomy is essential for preventing complications during surgery.

Mitral Stenosis

Mitral stenosis (MS) is a narrowing of the mitral valve, most commonly caused by rheumatic heart disease. Though the prevalence of MS has decreased in the Western world, immigration from nonindustrialized countries has contributed to a resurgence.[1] In low-resource regions, rheumatic heart disease remains a significant health concern, affecting about 7 per 1000 children.[2][3][4] The primary cause of MS is commissural fusion, where the valve leaflets become adherent over time, leading to obstruction. Rheumatic heart disease initiates this process by causing inflammatory deposits on the valve apparatus, eventually leading to thickening, calcifications, and fibrosis. This progressive damage results in a narrowed valve, typically manifesting years after the initial rheumatic heart disease episode.

One of the earliest consequences of MS is an increased mitral valve diastolic gradient, driven by the reduction in valve area. This elevated gradient raises left atrial pressure, often causing left atrial dilation. A dilated left atrium increases the risk of atrial fibrillation and the formation of left atrial thrombi, particularly in the appendage. Chronic MS may lead to pulmonary hypertension as a result of increased pulmonary artery pressures secondary to the elevated left atrial pressure. Over time, this can progress to right heart failure with right ventricular hypertrophy and dilation, potentially affecting the tricuspid valve through either rheumatic involvement or secondary consequences of MS.

MS can also arise from congenital defects like a parachute mitral valve, as well as other etiologies such as infective endocarditis, systemic lupus erythematosus, carcinoid disease, rheumatoid arthritis, and chest radiation. Nonrheumatic causes include calcific extension from degenerative aortic stenosis, which can lead to annular dilation and leaflet calcification. Some conditions, such as cor triatriatum, left atrial myxoma, and pulmonary vein stenosis, can mimic MS in adults.[5]

Pregnancy can often unveil a previously compensated MS, as pregnancy often increases cardiac output and causes associated tachycardia, especially 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 individuals; this is why percutaneous mitral valve valvuloplasty is an indicated therapeutic intervention in these patients.[6][7] The goal of mitral valve intervention in this specific population is not to fully repair but to improve the patient's hemodynamic status.[8]

The severity of MS is often assessed using different scoring systems, such as the Cormier score, which groups the valve anatomy into 3 categories, and the Wilkins score, which grades the valve based on mobility, thickening, calcification, and subvalvular thickening. These evaluations help guide treatment decisions and surgical interventions. In addition to these echocardiography-based scoring systems, other systems from distinct radiologic modalities also exist to augment and improve their accuracy.[9][10][11][12] Understanding the pathophysiology of MS is crucial in guiding its diagnosis. A thorough history and physical examination, combined with advanced imaging techniques, play an essential role in confirming the presence and severity of MS, aiding in identifying clinical symptoms, hemodynamic changes, and structural abnormalities of the mitral valve. This includes: 

• Presentation: Patients with MS often present with symptoms such as fatigue, dyspnea, orthopnea, or paroxysmal nocturnal dyspnea due to reduced cardiac output and pulmonary congestion. Left atrial dilation, a consequence of increased pressure, can lead to atrial fibrillation, which may present with palpitations or worsening symptoms. Compression of adjacent structures due to the enlarged left atrium may cause dysphagia from compression of the esophagus or the rare occurrence of Ortner syndrome, characterized by hoarseness due to recurrent laryngeal nerve compression. Long-standing MS may result in pulmonary hypertension, leading to symptoms like peripheral edema or ascites due to right heart failure.
• Physical examination: Patients may exhibit an irregular, low-volume pulse due to atrial fibrillation or reduced stroke volume. Cardiac auscultation typically reveals a loud S₁ and a mid-diastolic rumbling murmur heard best at the apex, with the intensity correlating with the severity of the mitral valve gradient. A prolonged diastolic murmur suggests more severe stenosis.
• Electrocardiogram: These findings in MS can vary depending on the disease stage. Early stages of MS may reveal normal sinus rhythm, while advanced stages often present signs of left atrial enlargement, such as wide, notched P waves (P mitrale) that appear M-shaped. Atrial fibrillation is common in patients with significant left atrial dilation.
• Imaging: Chest radiography may reveal left atrial enlargement, a hallmark of advanced MS. However, echocardiography is the diagnostic gold standard. This imaging modality evaluates the entire mitral valve apparatus, including leaflet structure, annular size, left atrium size, and left ventricular function. Both transthoracic and transesophageal echocardiography are essential for assessing pulmonary hypertension and quantifying the mitral valve gradient. Echocardiography may reveal:
  • The parasternal short-axis view allows for direct measurement of the mitral valve area using planimetry, crucial for determining stenosis severity. Commissural fusion, a key feature of rheumatic MS, is also best viewed from this perspective. The parasternal long-axis view provides detailed visualization of the anterior and posterior leaflets and the subvalvular apparatus.
  • The "hockey stick" sign indicates restricted anterior leaflet motion and is a classic echocardiographic finding in MS.[13] In addition to planimetry, the mitral valve area can be calculated using the pressure half-time method, best assessed through the 4-chamber apical view. The apical view is also ideal for measuring the mean pressure gradient across the valve.
• Integrated evaluation: No single echocardiographic parameter determines the severity of MS; for accurate assessment, a comprehensive evaluation of mitral valve morphology, including mitral valve area, mean pressure gradient, and systolic pulmonary artery pressure, is necessary.[14][15][16][17]

Classifications of Mitral Stenosis

European guidelines 

• Mild: Valve area >1.5 cm², mean gradient <5 mm Hg, systolic pulmonary artery pressure <30 mm Hg
• Moderate: Valve area 1.0-1.5 cm², mean gradient 5 to 10 mm Hg, systolic pulmonary artery pressure 30 to 50 mm Hg
• Severe:Vvalve area <1.0 cm², mean gradient >10 mm Hg, systolic pulmonary artery pressure >50 mm Hg [18]

American Heart Association guidelines [7]

• Progressive MS: Valve area >1.5 cm², diastolic pressure half-time <150 msec
• Severe MS: Valve area ≤1.5 cm², diastolic pressure half-time ≥150 msec
• Very Severe MS: Valve area <1 cm², diastolic pressure half-time >220 msec

Indications

Mitral valve commissurotomy is a surgical or percutaneous procedure performed to relieve MS by separating the fused mitral valve leaflets, thereby improving valve function and blood flow. The primary indication for mitral valve commissurotomy is symptomatic, moderate-to-severe MS, particularly when caused by rheumatic heart disease. Several key criteria guide the decision to proceed with this intervention:

• Symptomatic MS
  • Patients with symptoms such as dyspnea, fatigue, and orthopnea consistent with New York Heart Association functional classes II through IV are candidates for mitral commissurotomy. The severity of the symptoms correlates with the mitral valve area, typically less than 1.5 cm², which causes significant obstruction of blood flow.
• Pulmonary hypertension
  • Severe MS leading to pulmonary hypertension (pulmonary artery systolic pressure >50 mm Hg at rest) is an indication for intervention, even if patients are minimally symptomatic. Treating MS can reduce pulmonary artery pressures and prevent further right heart dysfunction.
• Atrial fibrillation
  • Patients with MS and new-onset or recurrent atrial fibrillation, especially when associated with rapid ventricular response or anticoagulation challenges, may benefit from commissurotomy to improve hemodynamic status and reduce left atrial size.
• Contraindications to open surgery
  • Percutaneous mitral balloon commissurotomy (PMBC) is preferred for high-risk surgical candidates. PMBC offers a less invasive alternative to open surgical commissurotomy, with a shorter recovery time and lower perioperative risk.

Contraindications

Mitral commissurotomy, both open and percutaneous, is a key intervention for treating MS, but not all patients are suitable candidates. Choosing an open or percutaneous approach depends on patient anatomy, underlying pathology, and specific contraindications.

General Contraindications to Open Mitral Commissurotomy and PMBC

• Severe mitral regurgitation
  • Both procedures focus on relieving stenosis by separating the fused commissures, but they may increase the risk of worsening mitral regurgitation due to leaflet damage or altered valve structure. In such cases, valve repair or replacement is preferable.
• Mitral valve area ≥1.5 cm²
  • Commissurotomy is generally indicated when the mitral valve area is less than 1.5 cm². This creates a diastolic pressure gradient across the valve, which leads to increased left atrial pressure and subsequent symptoms of heart failure.
• Extensive valve calcification
  • Heavily calcified mitral leaflets or subvalvular structures make commissurotomy less effective, as the valve tissue is rigid and cannot be adequately separated. A high Wilkins score (indicating thickening, calcification, and reduced mobility of the valve) suggests that the patient may not benefit from either approach, and mitral valve replacement is often recommended.
• Left atrial thrombus
  • A thrombus in the left atrium, particularly in the left atrial appendage, contraindicates open and percutaneous commissurotomy. Manipulation of the valve during the procedure can dislodge the thrombus, increasing the risk of embolic events such as stroke. Transesophageal echocardiography
  • is typically required to exclude the presence of a thrombus before the procedure.
• Active endocarditis or infection
  • Valve manipulation can worsen the infection and increase the risk of embolic complications. Infected tissue is also more fragile, increasing the likelihood of valve rupture or damage.
• Severe pulmonary hypertension (irreversible)
  • In patients with irreversible pulmonary hypertension secondary to long-standing MS, relieving the mitral obstruction may not improve pulmonary artery pressures or right heart function. Both open and percutaneous approaches are generally contraindicated in this setting, as the benefits of valve intervention may be minimal.
• Concomitant severe aortic valve disease
  • Patients with severe aortic valve disease (stenosis or regurgitation) are typically not suitable candidates for commissurotomy, as they may require more extensive valve surgery. Combined surgical procedures, such as double valve replacement, are more appropriate.
• Congenital valve abnormalities
  • Certain congenital abnormalities may limit the success of commissurotomy. One example is a parachute mitral valve where the chordae tendineae attach to a single papillary muscle. Patients with congenital valve abnormalities often require surgical valve replacement rather than commissurotomy, as commissural splitting may not resolve the obstruction.[19]

Specific Contraindications to PMBC

• Unfavorable valve morphology
  • PMBC is most effective in patients with relatively pliable, noncalcified valves. Patients with a high Wilkins score or heavy calcification of the commissures and subvalvular apparatus are not good candidates for the percutaneous approach. The risk of complications, including mitral regurgitation and failure of valve dilation, is high in these patients.
• Mitral annular calcification 
  • Extensive mitral annular calcification (MAC) poses a significant challenge for the percutaneous approach. MAC can prevent adequate balloon expansion and may lead to complications such as valve rupture or failure to achieve adequate stenosis relief. In such cases, surgical options are preferred.
• Severe subvalvular disease
  • Severe involvement of the subvalvular apparatus, such as chordal thickening or fusion, can limit the effectiveness of percutaneous commissurotomy. Balloon dilation may not adequately relieve stenosis, and there is a risk of damaging the subvalvular structures, leading to significant mitral regurgitation. In these cases, open commissurotomy or valve replacement is recommended.
• Atrial septal defect 
  • PMBC requires transseptal access to the left atrium by creating an atrial septal defect. Preexisting atrial septal defects may increase the risk of paradoxical embolism or complicate the procedure. In patients with significant septal abnormalities, open surgery may be a safer option.
• Severe coronary artery disease 
  • Coronary artery disease requiring coronary artery bypass grafting favors an open approach to mitral commissurotomy.[20][21]

Specific Contraindications to Open Mitral Commissurotomy

• Severe comorbidities
  • Open mitral commissurotomy requires cardiopulmonary bypass and is a highly invasive procedure, carrying a higher risk in patients with severe comorbidities, such as advanced heart failure, chronic obstructive pulmonary disease, or significant renal impairment. In these patients, the risks of surgery may outweigh the benefits, and less invasive options should be considered.
• Previous cardiac surgery
  • Patients who have undergone prior cardiac surgery, particularly mitral valve surgery or other complex procedures, may have adhesions or scarring that complicate repeat open-heart surgery. The increased surgical risk in such cases may lead to consideration of alternative interventions, such as percutaneous options or valve replacement.

Equipment

The required equipment is primarily based on the type of technique used. For percutaneous technique, the following is needed:

• Multiple wires and sheath sizes
• Cath laboratory/hybrid room with fluoroscopy
• Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE)
• machine
• Mitral valve repair device
• Code cart
• Sterile gown and gloves, sterile drape
• Anesthesia
• Operative cardiac surgical team and open surgical trays
• X-ray lead

The open technique requires the following:

• The operative cardiac surgical team
• Open surgical instruments
• TTE and TEE machine
• Code cart
• Anesthesia
• Sterile gown and gloves
• Ink and saline injectors

Personnel

Successful repair via the percutaneous or open approach 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 (in many cases, the anesthetist is conducting the TEE)

Preparation

Preparation for a mitral commissurotomy, whether open or percutaneous, involves meticulous preoperative assessment and optimization to ensure the best outcomes. This process begins with a comprehensive evaluation of the patient's clinical status, including detailed history taking, physical examination, and laboratory testing. Patients are assessed for signs of heart failure, arrhythmias such as atrial fibrillation, and thromboembolic risk that may require anticoagulation therapy.

Cardiac imaging, particularly echocardiography, is essential to evaluate the mitral valve anatomy, including leaflet mobility, calcification, commissural fusion, and subvalvular apparatus involvement. The Wilkins or Cormier scoring systems may be used to determine the suitability for commissurotomy. Coronary angiography is recommended for patients with risk factors for coronary artery disease to rule out significant stenosis that might require concomitant revascularization. Pulmonary pressures are also assessed to determine if pulmonary hypertension is present, influencing surgical decisions.

Patients with atrial fibrillation or those with a history of thromboembolism may undergo TEE to exclude left atrial thrombus, especially in the left atrial appendage. Preoperative management includes stabilizing heart failure symptoms, optimizing fluid balance, and controlling heart rate in patients with arrhythmias. The anesthesia team will evaluate to ensure patients are fit for the chosen surgical approach and plan for intraoperative monitoring, including the potential use of TEE for real-time assessment of the mitral valve during the procedure. All surgical procedures in the hybrid or operating room should be performed within a sterile field, and all precautions should be taken to maintain sterility.

Technique or Treatment

Open Mitral Valve Commissurotomy

The open surgical approach has long been regarded as the gold standard for mitral valve stenosis repair.[22] Although the percutaneous technique is newer and lacks the long-term data available for open or closed techniques, numerous study results demonstrate that the open method consistently delivers excellent results. This approach offers the advantage of direct visualization of the entire mitral valve, enabling precise repair. While the open technique requires cardiopulmonary bypass, the closed method can avoid this step. Over time, study results have consistently shown open commissurotomy to be a safe and highly effective procedure with outstanding outcomes.[23]

Technique

The open mitral commissurotomy technique typically involves a median sternotomy to access the chest, although a right or left thoracotomy may also be employed for mitral valve access. A right thoracotomy combined with femoral cannulation can be used to avoid a midline sternal incision, particularly in patients with a history of prior thoracic surgery. Once the chest is opened, cardiopulmonary bypass is initiated via aortic and bicaval venous cannulation, followed by the administration of cardioplegia. After establishing cardiopulmonary bypass, the left atrium is opened, and the mitral valve is exposed using 1 of 3 approaches: interatrial groove, transatrial oblique, or transatrial longitudinal septal. Each approach has unique advantages and disadvantages. Upon reaching and adequately exposing the mitral valve, 2 polypropylene sutures are placed to gently retract the mitral leaflets toward the superior left atrium, although nerve hooks can also be used; this maneuver allows for proper visualization of the mitral commissural fusion.

Once the commissural fusion is identified, the chords and papillary muscles are examined through the mitral orifice for signs of calcification, shortening, or fusion to the subvalvular apparatus. A right-angle clamp is passed through the orifice and positioned below the fused mitral commissures. The clamp is then opened slightly, allowing a #15 or #11 blade scalpel to carefully cut through the commissures without damaging the underlying structures. The first incision is made 5 mm from the annulus on top of the clamp, extending downward into the fused chords and papillary muscles, and then carried toward the mitral orifice. If the incision does not enter the head of the papillary muscle, it may result in papillary muscle division, necessitating repair or reimplantation. Care must be taken not to overextend the commissurotomy, as this could lead to mitral valve incompetence, which may require annuloplasty or commissuroplasty to correct. The effectiveness of the mitral repair should be evaluated both during and after cardiopulmonary bypass.

During bypass:

• Saline injection test
  • This test was first introduced in 1983 by Dr Alain Carpentier when he presented his seminal paper "Cardiac Valve Surgery: the ‘French Correction’" at the sixty-third annual meeting of the American Association for Thoracic Surgery in Atlanta, GA. Dr Carpentier advocated the injection of saline into the ventricular cavity through the valve using a bulb syringe, ensuring that the aortic root is vented beforehand to prevent air from entering the coronary arteries and causing embolism. The absence of leakage after saline injection indicates proper leaflet coaptation, giving a degree of confidence about the efficacy of the repair.[24]
• Ink test
  • Proposed in 2007 by Adams and Anyanwu, this technique involves injecting saline to distend the mitral leaflets into their systolic position. Any identified leaks, if present, are corrected using appropriate methods. The tip of a surgical marking pen is held with a surgical clamp and used to mark the closure line from the anterior to the posterior commissure, leaving a residual reference line on both leaflets. Ideally, a symmetric line of closure displaced toward and parallel to the posterior aspect of the annuloplasty ring should be observed. The saline is then aspirated from the ventricle, allowing for the inspection of each leaflet. The height of the residual leaflet below the marked closure line represents the leaflet available to create the coaptation surface. This unmarked zone is examined, and in an optimal repair, there should be almost 4 mm of leaflet beyond the marked line. Notably, some ink enters the coaptation zone, underestimating the true coaptation surface by a few millimeters.[25]

After bypass:

• Postprocedure TEE
  • This is the most reliable method for directly visualizing the repaired valve and assessing residual stenosis or incompetence, as this test is performed on a beating heart. However, its drawbacks include the difficulty of making repairs on a beating heart and potential hemodynamic differences between a patient who is awake or anesthetized, which can result in inaccurate measurements of valvular function.

Closed Mitral Valve Commissurotomy

Closed mitral valve commissurotomy has been a widely used technique for repairing MS since the 1920s, especially in developing countries where it remains a popular option due to its lower cost and simplicity than open surgery. While it is rarely performed in the United States today due to the success of the open commissurotomy with cardiopulmonary bypass, the closed technique is still valuable in select patient populations. This method does not provide direct visualization of the mitral valve but can now be performed through a small thoracotomy incision with port placement and guidance from TEE.[26] This method continues to be an important option in resource-limited settings, where its cost-effectiveness and minimal technical requirements make it preferable over more advanced surgical techniques.[27][28]

Technique

In closed mitral valve commissurotomy, the surgeon typically accesses the heart through a left posterolateral or anterolateral thoracotomy at the level of the fifth rib. The lung is retracted posteriorly, and an incision is made parallel to the phrenic nerve. The pericardium is opened, and traction sutures are placed. The left atrial appendage is excluded using a side-biting clamp, followed by placing a polypropylene purse-string suture around the appendage. A second purse-string suture with pledgets is placed at the apex of the left ventricle.

The left atrial appendage is opened, and the surgeon inserts an index finger into the left atrium to palpate the mitral valve, assessing for calcification, stenosis, or insufficiency. Before this step, a thrombus should be ruled out by digital palpation. If a clot is found, it should be excluded with a clamp and removed. Failure to remove the thrombus necessitates aborting the closed technique and converting to an open commissurotomy with cardiopulmonary bypass. The index finger should remain in the left atrium for no more than 2 to 3 cardiac cycles, as prolonged insertion may cause arrhythmias or even 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. With the heart elevated, the surgeon makes a small ventriculotomy using a #11 blade inside the left ventricular purse-string suture.

Once the ventriculotomy is made, Hagar dilators are used to expand the ventriculotomy until the Tubb valvulotome can be passed through the left ventricle, across the mitral valve, and into the left atrium. The valvulotome is opened quickly to a preset measurement (typically 3.5-4.5 cm), closed immediately, and removed. Once the instrument and finger are removed, the purse-string suture at the left ventricle is tied down over pledgets. Care must be taken to avoid premature opening of the valvulotome, as this can damage the subvalvular apparatus and cause mitral insufficiency. If the Tubb dilator cannot fully dilate the valve, this indicates the need for open commissurotomy.

Any time a patient is undergoing a closed commissurotomy, it is standard practice to have cardiopulmonary bypass equipment available at the bedside during closed commissurotomy in case urgent conversion to open surgery is needed. Once the procedure is complete, a cardiac echocardiogram is performed to assess the mitral valve area, left atrial and pulmonary pressures, and the degree of any mitral regurgitation caused by the procedure.[29] Studies have shown that this technique can achieve excellent results, including significant improvement in valve area without the need for cardiopulmonary bypass, making it a valuable option in certain clinical scenarios.[30]

PMBC

PMBC is now the standard treatment for MS in patients with favorable valve anatomy. Introduced in the mid-1980s, it has become the first-line therapy for patients who meet the mitral valve balloon dilation criteria. Patient selection is crucial when determining the most appropriate treatment option, with considerations given to valve anatomy and the surgical team's experience. PMBC shows excellent long-term outcomes, particularly in younger individuals who initially had a larger valve area before the intervention, with study results demonstrating favorable results over 15 years.[31] 

Various approaches have been taken to balloon dilation of the mitral valve. Although a double-balloon technique was historically used, the Inoue balloon has become the preferred choice due to its technical ease and lower complication rates.[32] After the procedure, most patients experience immediate hemodynamic improvements, including increased valve area and reduced mitral valve gradient. Upon follow-up, many patients with New York Heart Association (NYHA) class III symptoms improve to NYHA class II. Like the open surgical technique, PMBC splits the stenotic commissures by inflating the balloon within the valve.

Technique

The procedure begins with the groin being prepped and draped in a sterile fashion. Ultrasound guidance is used to access the femoral vein, and a sheath and wire are placed with the wire advanced into the right atrium. Transseptal catheterization is a crucial step in the process, as it allows access to the left atrium. Once in the left atrium, the Inoue balloon is introduced. The Inoue balloon features 3 segments with different elastic strengths, allowing for sequential inflation. Balloon sizes range from 24 mm to 30 mm and are selected based on the patient's height, body surface area, or maximal intercommissural distance.[33] 

Under echocardiographic guidance, the balloon is positioned across the mitral valve and inflated sequentially, starting with the smallest portion of the balloon. Once the valve is dilated, the balloon is withdrawn into the left atrium, and the valve is assessed for improvements in the valve area and any resulting mitral regurgitation.[34] If the valve area is insufficient after the first attempt, the balloon can be reintroduced for additional dilation. The procedure is successful when follow-up echocardiography shows a valve area greater than 1 cm²/m² of body surface area, complete opening of at least 1 commissure, or a controlled increase in mitral regurgitation. Since a slight reduction in valve area may occur within the first 24 to 36 hours, echocardiography should be repeated afterward. Numerous study results confirm that PMBC significantly improves valve area, reduces left atrial pressure, enhances coronary flow, and increases cardiac index.[35]

Complications

The risks associated with mitral valve repair are similar, whether done through open surgery or transcatheter percutaneous repair. Recent studies have shown no deaths related to the repair and an overall complication rate of less than 3%. The following are some critical complications:

• Catheter-related complications to access the site, such as hematoma, arteriotomy, dissection, arteriovenous fistula
• Stroke
• Myocardial infarction due to damage or irritation to the left coronary artery
• Perioperative bleeding and resulting blood product 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 [36][37]

Clinical Significance

Mitral commissurotomy is a crucial treatment for MS, delivering significant clinical benefits that improve valve function, alleviate symptoms, and enhance overall quality of life. This procedure increases the size of the mitral valve orifice, reduces left atrial pressure, and mitigates symptoms such as dyspnea and fatigue. By addressing these issues, commissurotomy can help prevent complications like atrial fibrillation and thromboembolism associated with MS while also lowering pulmonary hypertension and improving cardiac output. This intervention delays or eliminates the need for valve replacement for many patients, making it particularly appealing for younger individuals with favorable valve anatomy.

PMBC offers a minimally invasive alternative to surgical methods, featuring quicker recovery times and lower complication rates. This approach proves especially beneficial for patients at high surgical risk or those who prefer less invasive procedures. Overall, whether performed via open or percutaneous techniques, mitral commissurotomy results in excellent long-term outcomes, particularly when patients are carefully selected, ultimately enhancing both hemodynamics and quality of life.

Enhancing Healthcare Team Outcomes

Effective patient-centered care for mitral commissurotomy requires a collaborative approach involving advanced clinicians, nurses, pharmacists, and other health professionals. Each team member is critical in preoperative assessment, intraoperative management, and postoperative care. Advanced clinicians lead the clinical decision-making process, using their expertise to select appropriate candidates for the procedure. They must communicate clearly with the nursing team to ensure patient education, consent, and preoperative assessments are thoroughly conducted. Nurses are vital in monitoring patient vitals, administering medications, and supporting patients and families while facilitating smooth communication between disciplines.

Pharmacists contribute by managing anticoagulation protocols and other medications essential for perioperative care, ensuring that potential drug interactions are addressed. Interprofessional communication is vital to optimize care coordination, with regular team meetings and updates to share patient progress and address any concerns. Strategies such as utilizing electronic health records for real-time information sharing and employing standardized protocols for postoperative monitoring enhance patient safety and outcomes. By fostering collaboration and respect among all health professionals, the team can improve performance and deliver high-quality, patient-centered care throughout the mitral commissurotomy process.

Nursing, Allied Health, and Interprofessional Team Monitoring

Nurses, technicians, and clinicians from various specialties play a crucial role in patient monitoring throughout the mitral commissurotomy process. Preoperative, intraoperative, and postoperative care demands seamless interprofessional communication between all teams involved. This collaboration ensures that each procedure phase is carefully managed, improving patient safety, better outcomes, and enhanced team performance. A skilled, cohesive team is essential for monitoring patient progress, addressing complications, and making timely interventions during the operative course, creating a more efficient and patient-centered care environment.