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Endoscopic Mitral Valve Repair

      Since 1997, over 2000 patients have undergone total endoscopic mitral valve repair at the Onze-Lieve-Vrouw Clinic in Aalst, Belgium.
      • Casselman F.P.
      • Van Slycke S.
      • Wellens F.
      • et al.
      Mitral valve surgery can now routinely be performed endoscopically.
      • Casselman F.P.
      • Van Slycke S.
      • Wellens F.
      • et al.
      From classical sternotomy to truly endoscopic mitral valve surgery: a step by step procedure.
      • Casselman F.P.
      • Van Slycke S.
      • Dom H.
      • et al.
      Endoscopic mitral valve repair: feasible, reproducible, and durable.
      This article describes the approach to mitral valve repair using ThruPort (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 minithoracotomy. Preoperatively, patients who met the indications for mitral valve repair were evaluated by cardiac catheterization, pulmonary function tests, and magnetic resonance imaging to exclude patients with whom this procedure is not deemed appropriate. Patients with severe peripheral vascular disease, a dilated ascending aorta >4.5 cm, or those with lung adhesions that might render the access impossible to the right hemithorax are excluded.
      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 postcardiopulmonary 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 lumen on the 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 >93% at 4 years.
      • Casselman F.P.
      • Van Slycke S.
      • Dom H.
      • et al.
      Endoscopic mitral valve repair: feasible, reproducible, and durable.

      Operative Technique

      Figure thumbnail gr1
      Figure 1Patient positioning. Patient is placed supine on the operating table with an inflatable cushion under the chest to elevate the right hemithorax and to open up the intercostal spaces (ICS). The right arm is slightly flexed. The anesthesiologist places a central venous line, a right radial arterial line, a double-lumen endotracheal tube, and a TEE probe. In addition, a 17-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 2Preparation of the right hemithorax 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 2 to 3 intercostal spaces caudal to the right minithoracotomy for CO2 administration and a left atrial vent line. The 5-mm thoracoscope is placed in the same interspace as the thoracotomy at the level of the anterior axillary line. Medially, a 5-mm cut-down is made parasternally for placement of the left atrial retractor that is fixed to a Bookwalter 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 fibrous portion of the diaphragm and pulled through the inferior chest wall to complete the thoracoscopic field. ICS = intercostal space.
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      Figure 3Percutaneous venous peripheral cannulation. Once the patient is adequately anticoagulated (activated clotting time >400), we make a 1-cm cut down in the left groin, and the femoral vein is punctured with a 21-G needle. The Seldinger technique is used to place a guidewire into the right atrium under TEE guidance. A 25-Fr venous cannula is advanced over the wire after dilating and is positioned in the right atrium.
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      Figure 4Percutaneous arterial peripheral cannulation. Similar to the venous cannulation, the femoral artery is punctured and a guidewire is placed into the descending aorta under TEE guidance. First, 2 polypropylene sutures are placed with the Perclose Proglide System (Abott Vascular, Chicago, IL) for percutaneous closure afterward. The artery is dilated and a 21- to 23-Fr arterial cannula is placed and secured.
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      Figure 5EndoClamp insertion. The EndoClamp is inserted via the hemostatic valve through the side arm of the arterial cannula into the ascending aorta under TEE control. CPB is initiated.
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      Figure 6Opening of the pericardium and endoballoon clamping. Once on bypass, the pericardium can be opened safely and exposure of the interatrial groove can be obtained. On initiating CPB, confirmation of superior vena cava (SVC) and inferior vena cava (IVC) cannulae placement and complete drainage of the right side of the heart must be obtained.
      The EndoClamp balloon is directed up the descending thoracic aorta and passed around the arch of the aorta to the sinotubular junction under TEE direction. 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 counterforces of the CPB flow versus tension on the balloon line, which is locked against the arterial inflow cannula. 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 midportion 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 artery as well as blood flow to the brain. Ao = aorta; Rt = right.
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      Figure 7Left atrial retractor. The left atrial retractor is designed with an arch to keep away the posterior wall of the left atrium. By turning the black knob at the end of the shaft, we can change the angle of the retraction blade that is entering the left atrium. By making it more obtuse, we avoid collisions with our instruments against the blade.
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      Figure 8Exposure of the mitral valve. Visualization is now best accomplished with a 30-degree scope. The left atrium is opened 3 mm medial to the insertion of the pulmonary veins. The left atrial retractor is placed to allow complete exposure of the mitral valve. The arch holds away the posterior wall of the left atrium. The venting cannula is placed in the left upper pulmonary vein.
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      Figure 9Placement of the annular sutures. 2-0 Polyester sutures are placed in the annulus of the mitral valve and brought through the working port. We recommend placing the anterolateral commissural sutures first because these are the most difficult. After the first 4 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.
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      Figure 10Valve analysis. 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. In this case, a P2 prolapse with excess tissue is obviously seen.
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      Figure 11Triangular P2 resection. 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 8 mm. The gap is then closed with a running imbricating 4-0 polypropylene suture. The knot is tied at the level of the annulus. If the new scallop is still too high, a Gore-Tex (Flagstaff, AZ) chord from the papillary muscle is placed at the free edge.
      Figure thumbnail gr12
      Figure 12Placement 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 competence and symmetry of the repair. Concomitant atrial ablation can be easily performed before closure of the left atrium if necessary.
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      Figure 13Closure of the left atrial incision. After the venting catheter is placed into the ventricle, the left atrium is closed with a running 3-0 polypropylene suture. 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 sutures placed in the artery of the Perclose Proglide system (Abott Vascular) are tied. SVC = superior vena cava.
      Figure thumbnail gr14
      Figure 14Closure of the pectoral muscle and skin incision. One chest tube is placed in the right pleura. A Jackson-Pratt drain is placed into the pericardium under the inferior vena cava. It is important to close the muscle precisely to avoid lung herniation. The skin is closed intradermally.

      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.
      • Svensson L.G.
      • Atik F.A.
      • Cosgrove D.M.
      • et al.
      Minimally invasive versus conventional mitral valve surgery: a propensity-matched comparison.
      • Iribarne A.
      • Russo M.J.
      • Easterwood R.
      • et al.
      Minimally invasive versus sternotomy approach for mitral valve surgery: a propensity analysis.
      Postoperatively, patients are monitored overnight in the intensive care unit. Chest tubes are removed on the second postoperative day. Patients' survival and freedom from reoperation are excellent and comparable to valves repaired using standard sternotomy approaches.
      In our experience, the adherence of Carpentierian principles and the performance of all known repair techniques can be routinely performed using the thoracoscope, which provides optimal visualization.
      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. 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 encouraging interventional cardiologists to continue their efforts to achieve percutaneous “repairs” without respect for the basic “Carpenterian” rules of mitral valve repair.

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        • et al.
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        From classical sternotomy to truly endoscopic mitral valve surgery: a step by step procedure.
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