Transcatheter Valve Interventions

Transcatheter Valve Repair/Replacement

Overview

• Transcatheter valve interventions include various types of repairs or replacements on any of the four heart valves:^1-4
  • Transcatheter edge-to-edge repair may be performed on the mitral or tricuspid valve, although the technique for each valve differs due to the significant differences in anatomy.
  • Transcatheter mitral valve replacement/repair (TMVR)
  • Transcatheter tricuspid valve replacement/repair (TTVR)
  • Transcatheter aortic valve replacement: discussed in a different summary: Link.
  • Transcatheter pulmonic valve implantation is usually performed in patients with congenital heart disease.⁵
• Transcatheter valve interventions are the most minimally invasive when compared to traditional full median sternotomy and mini-thoracotomy or port-access approaches:
  • Percutaneous transcatheter approach: the femoral vein is accessed, and a guidewire is threaded into the heart to repair or to deploy new valves.
  • Transapical or transatrial transcatheter approach: via a small incision in the anterior chest wall.
• Surgical approaches to tricuspid valve repair/replacement are typically only performed when concomitant left-sided cardiac surgery is required.
• Transcutaneous tricuspid valve procedures are becoming increasingly commercially available for those with isolated tricuspid valve pathology. However, the anatomy of the tricuspid valve may make many transcatheter interventions more technically difficult.⁴

Indications and Contraindications

• Repair vs. replacement depends on the location and extent of the damage to the valve and the valvular anatomy.
• A surgical approach is more suitable for patients who need multiple interventions (i.e., mitral valve [MV] replacement and coronary artery bypass grafting (CABG) and/or aortic valve replacement), or patients who have unsuitable anatomy for a transcatheter approach1
• Transcatheter approaches are preferred for patients who have failed maximum goal-directed medical therapy, are at high risk for an open-heart approach, and have suitable anatomy for transcatheter access.²
• Patients who already have severe disease from their tricuspid regurgitation (liver and kidney disease, weight loss, chronic fatigue) may not benefit from valvular intervention.⁴

Procedure

• Typical procedural approaches for each type of valve repair or replacement are listed in Table 1.
• Transseptal approach:³
  • The surgical team obtains central femoral venous access
  • TEE analysis of the interatrial septum to determine the appropriate location for puncture of the septum; analysis of any preexisting effusions.
  • Watch for complications during transseptal puncture: accidental puncture of the aorta or left atrium (bleeding or cardiac tamponade).
  • If transseptal puncture is successful, IV heparin is administered with a goal activated clotting time (ACT) greater than 250-300 seconds.
  • Wire threaded into the left atrium or left pulmonary vein.
  • The femoral vein is serially dilated to allow for the introduction of the valve introducer sheath.
  • 3D TEE and fluoroscopic guidance allows for proper positioning of the device; this may require breath hold for stillness in addition to rapid ventricular pacing (140-180 beats per minute).
  • Valve position and function are confirmed before releasing from the introducer sheath.
  • Heparin is reversed with Protamine and the venous access site is closed.
  • The patient will have a residual atrial septal defect from this procedure; it is unclear if this is of clinical significance or associated with higher mortality and heart failure.³
• Transapical or transatrial approach^3,4
  • Most valves done transapically require a mini thoracotomy to access the chest wall.
  • Tricuspid valve access is via a right mini-thoracotomy into the right atrium; MV is accessed via a left mini-thoracotomy into either the left atrium (anterograde approach) or the left ventricle (retrograde approach).
  • The goal systolic blood pressure is typically less than 100mmHg before puncture of the heart through the chest wall to minimize bleeding risk; the goal blood pressure varies by institution.
  • Intravenous (IV) heparin is given at the time of intracardiac access; ACT is usually monitored every 30 minutes.
  • The guidewire and sheath are threaded across the valve.
  • The valve is deployed during rapid ventricular pacing (140-180 beats per minute to minimize cardiac motion), and its position is confirmed with fluoroscopy.
  • The cardiac access site is closed with sutures.

Anesthetic Management

• Preoperative evaluation:
  • Type and screen
  • Computed tomography and TEE imaging of valve anatomy
  • Coronary angiography to determine concomitant need for percutaneous coronary intervention (PCI) or CABG.
  • Risk stratification (Society of Thoracic Surgeons risk calculator and Euro System for Cardiac Operative Risk Evaluation): is the surgical risk high enough to warrant a transcatheter approach?
  • Ensure euvolemia and compliance with guideline-directed medical therapy.
  • Coordinate management of anticoagulants and antiplatelets, especially if neuraxial or regional anesthesia will be used for transapical procedures.
  • Determine whether an open surgical repair would be feasible in case of an intraoperative complication (conversation with the surgical team and the patient).³
• Intraoperative management:
  • Monitors and equipment:
  • Establish large-bore peripheral IV access.
  • Radial arterial line placement
  • Central venous access:
    • The anesthesia team can connect an infusion line to the surgical team’s femoral venous sheath in procedures in which the femoral vein is being accessed (i.e., transseptal approaches).
    • Consider placement of postinduction internal jugular central line in procedures that are transapical due to the higher risk of major bleeding in transapical approaches and the inability to slave off a femoral line.³
  • Defibrillator (guidewires can trigger arrhythmias)
  • TEE
  • Medication tray with emergency drugs and full-dose heparin in the event of need for CPB.
  • Choice of anesthetic:
  • If intraoperative TEE is to be used, or if a mini thoracotomy for a transapical approach is to be performed, general anesthesia with endotracheal intubation and muscle paralysis would be favored
  • Sedation may be feasible for procedures in which neither TEE nor a surgical cut-down is required.
  • For transapical procedures, preoperative paravertebral block may decrease analgesic requirements and reduce the incidence of postoperative atrial fibrillation, provided anticoagulants and antiplatelets are appropriately held in coordination with the procedural team.³
  • After induction, TEE is used to note any existing pericardial effusions, take preprocedural valve measurements, and guide appropriate points for access (interatrial septum or left ventricle).
  • Concerns during apical puncture include injury to the right ventricle, interatrial septum, and lateral papillary muscles.³
  • Heparinization: goal ACT greater than 250-300 seconds; ACT is typically measured every 30 minutes to prevent clotting.
  • Maintain hemodynamic status appropriate to the patient’s valvular pathology
  • Note that, postprocedure, although the valve pathology may be fixed, issues such as eccentric or concentric hypertrophy will remain.
• Postoperative care:
  • Typically, patients who underwent a transapical approach or who have ongoing needs for inotropic support will require intensive care unit admission.³
  • Patients with a less-complicated intraoperative course may be admitted to the postanesthesia care unit and then to the general cardiology floor.
  • TTE and chest x-ray postoperatively.
  • Discharged home on either dual antiplatelet therapy or anticoagulation therapy, depending on the type of valve deployed and other comorbidities that require anticoagulation.³

Complications

• General Complications:^3,4
  • Valve embolization (usually requires open extraction and repair, but may be percutaneously addressed in select situations)
  • Cardiac perforation or tamponade (needs emergent window or pericardiocentesis vs. percutaneous closure device vs. open surgical repair)
  • Major or fatal bleeding (8%)
  • Minor bleeding or bleeding at the access site (22%)
  • Arrhythmias requiring defibrillation
  • Air embolism
  • Compression or injury to the coronary artery requiring PCI or temporary circulatory support
  • Conduction blocks requiring pacemaker intervention
  • Need to convert to open procedure (if feasible to the patient’s situation)
• TMVR-specific complications:
  • Deployment of the valve can cause a left ventricular outflow tract (LVOT) obstruction if the mitral annulus sits too close to the LVOT (high rate of mortality; obstruction may be relieved by intentionally lacerating the A2 MV leaflet or through ablation of the interatrial septum).^2,3
  • Unlike the aortic annulus, the mitral annulus is in constant motion with the basal portion of the LV, which increases the risk of improper MV seating.²
  • Chordal rupture
• TTVR-specific complications:
  • Damage to or occlusion of the right coronary artery or coronary sinus⁴
  • Annuloplasty repairs: anchor or suture detachment⁴