Operative Techniques in Thoracic and Cardiovascular Surgery: A Comparative Atlas
Volume 12, Issue 4 , Pages 226-234, Winter 2007

Totally Endoscopic Mitral Valve Repair

  • Bradley S. Taylor, MD, MPH

      Affiliations

    • The York Hospital, York, Pennsylvania.
    • ,
  • Hugo K. Vanermen, MD

      Affiliations

    • The Department of Cardiovascular and Thoracic Surgery, The Onze-Lieve-Vrouw Clinic, 9300 Aalst, Belgium.
    • Corresponding Author InformationAddress reprint requests to Hugo K. Vanermen, MD, Chief of Cardiovascular and Thoracic Surgery, The Department of Cardiovascular and Thoracic Surgery, The Onze-Lieve-Vrouw Clinic, Moorselbaan 163, 9300 Aalst, Belgium.

Article Outline

 

Since 1997, over 1000 patients have undergone totally endoscopic mitral valve repair at the Onze-Lieve-Vrouw Ziekenhuis, in Aalst, Belgium.1, 2, 3 This article describes the approach to mitral valve repair using Port-Access (Edwards Lifesciences, Irvine, CA) technology to facilitate peripheral cannulation, endoballoon clamping of the ascending aorta, and access to the mitral valve through a non-rib-spreading right mini-thoracotomy. Preoperatively, patients who meet the indications for mitral valve repair are evaluated by cardiac catheterization, pulmonary function tests, and computed tomography to exclude patients with whom this procedure is not deemed appropriate. Patients with coronary artery disease, chronic obstructive pulmonary disease, which precludes single lung ventilation, Grade III-IV aortic atheromata, severe peripheral vascular disease, a dilated ascending aorta >4 cm, or those with lung adhesions that might render the access through the right hemi-thorax are excluded.3, 4

The successful conduct of endoscopic mitral valve repair surgery requires the coordination of perfusionists, nurses, anesthesiologists, and surgeons. The procedure is performed under general anesthesia with a double-lumen endotracheal tube. Transesophageal echocardiography (TEE) plays a vital role in venous cannulation, in EndoClamp (Edwards Lifesciences) balloon placement, and with assessing the valve both pre- and post–cardiopulmonary bypass (post-CPB). Femoral–femoral CPB with separate drainage of the superior vena cava is utilized along with endo-aortic clamping with an EndoClamp balloon. Cold crystalloid cardioplegia is delivered in an antegrade fashion via a port on the endoballoon EndoClamp. Long shafted instruments are used to carry out the procedure, while a 5-mm endoscope is used to optimize visualization of the intrathoracic cavity and valvular apparatus. In our experience, a team approach with well-trained specialists has resulted in excellent results with mortality of <1% and a freedom from reoperation of >94% at 4 years.3

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Operative Technique 

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  • Figure 1. 

    Patient positioning. Patients are placed supine on the operating table with an inflatable bladder to slightly elevate the right hemi-thorax. The right arm is slightly flexed. The anesthesiologist places a central venous line, a right radial arterial line, a double-lumen endotracheal tube, a temperature probe, and a transesophageal echocardiography (TEE) probe. In addition, a 14, 17 or 21 Fr venous cannula is placed in the right jugular vein before preparing the patient and initiating the operation. It will invariably ensure excellent venous drainage and allow for entering the right atrium, which cannot be achieved with a double-stage femoral cannula alone. Right radial artery pressures are monitored throughout the procedure to assess for EndoClamp balloon migration.

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  • Figure 2. 

    Preparation of the groin for CPB. Once the patient has been prepped and draped, a 2- to 3-cm incision is made at the level of the superior femoral triangle. Exposure of the anterior surface of the right femoral artery and vein is conducted. Transmural, longitudinal “U” stitches with 4-0 Gore-Tex (W.L. Gore & Associates, Inc, Flagstaff, AZ) with Teflon pledgets are placed on the artery and two 4-mm purse-strings on the vein are marked for easy identification. During this time, the scrub nurse and perfusionist prepare the EndoClamp and bypass cannulas. a. = artery; v. = vein.

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  • Figure 3. 

    Preparation of the right hemi-thorax and the working port. A 5-cm incision is performed in the inframammary groove and the intercostal space is entered. Next, a 7-mm port is placed two to three intercostal spaces caudal to the right mini-thoracotomy for CO2 administration and a vent line. The 5-mm 0-degree thoracoscope is placed in the same interspace as the thoracotomy at the level of the anterior axillary line. Medially, a 2-mm cut-down is made parasternally for placement of the left atrial retractor. A steel-wire is introduced through the superior chest wall to facilitate exposure of the valve after placement of the anterolateral annuloplasty sutures. Finally, a retraction suture is placed through the central tendon of the diaphragm and pulled through the inferior chest wall to complete the thoracoscopic field.

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  • Figure 4. 

    (A) Peripheral cannulation and placement of the EndoClamp. Once the patient is adequately anticoagulated (ACT > 400), the femoral vein is punctured with a 21-G needle. The Seldinger technique is used to place a guide-wire into the right atrium under TEE guidance. (B) A 25-Fr venous cannula is advanced over the wire with its dilators and is positioned at the junction of the right atrial inferior vena cava junction. Similarly, the femoral artery is punctured and a guide-wire is placed into the descending aorta under TEE guidance. The artery is dilated and a 21- to 23-Fr arterial cannula is placed and secured. The EndoClamp is inserted via the hemostatic valve of the arterial cannula into the ascending aorta under TEE control. CPB is initiated and the venous drainage is confirmed thoracoscopically. Once on bypass, the pericardium can be opened safely and exposure of the atrium can be obtained. If necessary, control of the inferior and superior cavae can be performed at this point in the operation. a. = artery; v. = vein.

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  • Figure 5. 

    (A) Initiation of CPB and Endoballoon Clamping. (Lower left) Upon initiation of CPB, confirmation of SVC and IVC cannulae placement and complete drainage of the right side of the heart must be obtained. Next, the EndoClamp balloon is directed up the descending thoracic aorta and passed around the arch of the aorta to the Sino-tubular junction under TEE direction (upper images). Inflation of the EndoClamp balloon results in occlusion of the ascending aorta and provides the ability to deliver antegrade cardioplegia. The balloon’s position is governed by the counter-forces of the CPB flow versus tension on the balloon line which is locked against the arterial inflow cannulae (lower right). It is not associated with radial forces of the balloon against the aortic wall. (B) Deployment of the EndoClamp and delivery of cardioplegia. Under TEE guidance, the EndoClamp balloon is partially inflated to 75% of the volume of the ascending aorta. This is followed by the injection of 0.25 mg/kg Adenosine via the cardioplegia line portion of the EndoClamp balloon to arrest the heart. The balloon is then inflated to occlude the ascending aorta completely and antegrade cardioplegia is delivered into the root. The balloon is positioned in the mid-portion of the ascending aorta between the sinotubular ridge and origin of the innominate artery. TEE visualization and pressure monitoring of the right radial artery confirm adequacy of placement. Loss of right radial artery pressure indicates that the EndoClamp balloon has migrated cranially and is obstructing the innominate arteries as well as blood flow to the brain. CVP = central venous pressure; IVC = inferior vena cava; SVC = superior vena cava; v. = vein.

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  • Figure 6. 

    Exposure of the mitral valve and placement of the annular sutures. Now, visualization is best accomplished with a 30-degree scope. (A) The left atrium is opened 3 mm medial to the insertion of the pulmonary veins. (B) The left atrial retractor is placed to allow complete exposure of the mitral valve. 2-0 polyester sutures are placed in the annulus of the mitral valve and brought through the working port. (C) We recommend placing the anterolateral commissural sutures first since this is the region with the risk of EndoClamp balloon perforation. (D) After the first four sutures are placed, they are retracted using the steel wire previously placed through the superior aspect of the chest. These sutures are placed under adequate tension to assist in the exposure. Examination of the mitral valve apparatus and left atrium is thoroughly conducted to evaluate for prolapse. Evidence of a jet lesion indicates prolapse of the opposing leaflet. The mitral annulus is evaluated for dilation and is measured at this time. Leaflet pliability and prolapse are also assessed. Distending the ventricle assesses retraction of the mid portion of the anterior leaflet by secondary chordae. The remaining annular sutures are then placed. IVC = inferior vena cava; SVC = superior vena cava.

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  • Figure 7. 

    Trapezoidal resection of P2. P2 is visualized and resected while preserving chordae tendinae of normal height adjacent to the prolapsed segment. Care must be taken not to resect too much tissue. The goal is to leave enough tissue to create a coaptation surface of 1.0 cm. If necessary, a sliding plasty can be performed by creating two transverse incisions along the annulus. Sutures are then placed taking correspondingly larger amounts of tissue along the annulus and smaller amounts of tissue on the leaflet edges. The two leaflet edges should meet and are ready to be reapproximated.

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  • Figure 8. 

    Reconstruction of the posterior leaflet. The resected segment of P2 is reapproximated with a running 4-0 polypropylene suture. The knot is tied at the level of the annulus and can be hidden below the ring once it is placed. Additional techniques can also be performed such as chordal shortening, chordal transfer, or the placement of Gore-Tex chordae.

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  • Figure 9. 

    Placement of the annuloplasty ring. Annular sutures are brought through the sewing ring in their corresponding position. Next, the ring is slid down to the annulus and the sutures are tied using a knot pusher. Performing a saline test confirms the competency and symmetry of the repair. Concomitant atrial ablation can be easily performed before closure of the left atrium. Once the atrium is repaired, a pacing wire is placed on the inferior wall of the left ventricle before deflating the EndoClamp balloon. De-airing and separation from bypass are performed in the usual fashion. Once off bypass, the femoral cannulae can be removed and the incisions are closed.

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Conclusions 

Endoscopic approaches to mitral valve repair have resulted in reduced intensive care unit and hospital stays, accelerated recovery times, improved postoperative pulmonary function, improved quality of life, reduced rehabilitation requirements, and improved cosmesis.1, 2, 3, 5, 6, 7, 8, 9, 10, 11 Postoperatively, patients are monitored overnight in the intensive care unit. Chest tubes are removed on the second postoperative day. Patients are evaluated 2 to 3 weeks after the operation so that they may resume normal activities. Annual follow-up with serial echocardiography is performed at our institution. Patient survival and freedom from reoperation are excellent and comparable to valves repaired using standard sternotomy approaches.1, 2, 3, 5, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21

In our experience, the adherence of Carpentierian principles17 and the performance of all known repair techniques can be routinely performed using the thoracoscope, which provides optimal visualization. Proponents of robotic-assisted thoracoscopic mitral valve repair report increased degrees of freedom that result in increased surgeon comfort while performing the repair.10 It is our opinion that the use of the robot results in more complexity in the operating room, increased setup times, enormous costs, and additional ports for instrumentation, and, most importantly, the fundamentals of mitral repair are altered to fit the technology. In addition, complex repairs of the posterior leaflet and debridement of mitral annular calcification cannot be accomplished easily. Despite early reports of feasibility, there are no long-term data reporting durability and freedom from reoperation to date for robotic-assisted mitral valve repair.

Totally endoscopic mitral valve repair is designed to have similar characteristics to the least invasive cardiology interventions that result in minimal scarring, no pain, and immediate rehabilitation 2 days after percutaneous intervention. By utilizing a non-rib-spreading endoscopic approach, we can come very close to this level of noninvasiveness by limiting the size of the scar and the magnitude of the physiologic response, and with this approach, afford the patient no pain and complete rehabilitation in 2 weeks. Cardiac surgeons who continue to perform sternotomy to manage repairable mitral valves with rehabilitation after 2 months are just encouraging interventional cardiologists to continue their efforts to achieve percutaneous “repairs” without respect for the basic “Carpentierian” rules of mitral valve repair.

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References 

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PII: S1522-2942(07)00123-7

doi:10.1053/j.optechstcvs.2007.10.003

Operative Techniques in Thoracic and Cardiovascular Surgery: A Comparative Atlas
Volume 12, Issue 4 , Pages 226-234, Winter 2007

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