We believe that three-dimensional (3-D) trans-esophageal (TEE) echocardiography is essential to plan both the simple and complex robotic mitral repairs. Although these operations can be done without this capability, the best pathologic valve definition is determined by a complete 3-D echo study, which also can provide reconstructive modeling. For topographic and dynamic nomenclature, we use Carpentier’s functional mitral insufficiency classification, which is based on leaflet motion characteristics: normal leaflet motion = Type 1, exaggerated (prolapse) leaflet motion = Type 2, and restricted leaflet motion = Type 3. Type 1 and 2 pathologies most commonly lend themselves to robotic mitral repairs, although ischemia related restriction (Type 3b) could be amenable to correction using these methods. As mentioned earlier, Type 3a rheumatic restriction is more difficult to treat using repair techniques.

Chapter 4 in this book details our methods for obtaining and reconstructing 3-D TEE images, which are acquired in the operating room just prior to beginning the repair operation. Briefly, we echo measure all leaflet segments (P₁-P₃, A₁-A₃) with particular attention to the length of A₂ as well as the height (annulus to coapting edge) of posterior leaflet segments. Next, the direction of each jet (leak) is mapped with both 2-D and 3-D studies. We have been able to define the exact direction and size of each regurgitant jet with 3-D TEE. Next, mobility and level of prolapse is determined for each Type II regurgitant lesions. Any regions of leaflet restriction are determined, and finally, commissural coaptation points with any associated leaks are defined.

We measure the planar angle between the aortic and mitral valve. If this angle is more acute than 120° then there is a greater chance of systolic anterior motion of the anterior leaflet (SAM) after the repair. This is especially true either with high (>2-cm) posterior leaflet segments (particularly at P₁ and P₂) or in the presence of an anterior leaflet A₂ segment length that is greater than 3-cm. Finally, the annular diameter, septal thickness at the outflow tract, and coaptation point to septal (C Sept) distances are measured. Either individually or collectively these measurements can influence the level of anterior leaflet to septal approximation during systole. When possible papillary muscle and chordal anatomy are defined in relation to ventricular size and cardiac contractility. Lastly, any annular or leaflet calcium should be determined, even though this problem can be elusive even with the best echo techniques and technologies.

After the above data have been acquired, a 3-D valve model is constructed from digital measurements. This static model can be imported directly to the da Vinci™ operating console via a program called TilePro™, providing surgeon visualization during the valve reconstruction. Any dynamic echocardiographic or angiographic images can be imported in the same way for the surgeon’s real-time review during the operation. It is our wish to continue to develop advanced real-time 3-D echocardiographic modalities that will enable more surgeons to perform complex mitral valve repairs with more engineering accuracy. Our experience of comparing echocardiographic, direct linear, and band sizer measurements of A₂ has shown an excellent correlation between all three lengths. From these data we have developed nomogram for annuloplasty band sizing (Table 24.2). In most cases these correlations have allowed us to rely on TEE measurements alone to select the best band size for implantation.

Robotic systems consist of tele-manipulators with end effectors, or micro-instruments, that are controlled remotely from a surgeon’s operating console. Currently, the da Vinci ™ surgical system is the only robotic system approved and available for to perform intra-cardiac surgical procedures. The latest version is the da Vinci™ SI HD (high-definition) surgical system, which was commercialized first in 2009. This system is comprised of an operating console, an electronic vision cart, and a surgical instrument cart. Figure 24.1 shows the overall operating room arrangement with end effector instruments used in robotic mitral valve surgery. For mitral repair surgery the instrument cart should be positioned (Fig. 24.2) along the left side of the patient with the overarching instrument arms entering the right chest. Individual instrument trocars and arms are inserted through specific intercostal spaces as shown in Figs. 24.3 and 24.4. After the two instrument arms, the 3-D camera, and the dynamic retractor have been inserted, the surgeon works from two hand driven robotic sensors that transmit digital instructions to the end effectors of each instrument (Fig. 24.5). A clutching mechanism enables constant re-adjustment of surgeon hand-positions to maintain an optimal ergonomic attitude with respect to the visual field.

In addition, this system offers a dual-console capability (Fig. 24.6), which enables surgeon training and the potential for collaboration during complex cases. In addition, the robotic EndoWrist ™ instruments have seven degrees of ergonomic freedom, which allow surgeons ideal dexterity using both dominant and non-dominant hands (Fig. 24.7). The wrist-like articulations at the ends of micro-instruments bring the pivoting action into the plane of the operative field, improving dexterity in tight spaces and allowing truly ambidextrous suture placement. The dynamic left atrial retractor provides ideal exposure of the mitral valve and is very easy to reposition (Fig. 24.8). This ability is absolutely necessary to allow full intra-atrial access and exposure for both mitral valve surgery and concomitant MAZE procedures for atrial fibrillation.

Chapters 3 and 5 describe in detail anesthetic management, cardiopulmonary perfusion, and myocardial protection for robotic mitral operations. This chapter will only briefly reiterate these techniques. With the patient in the supine position, either a double lumen endotracheal tube or bronchial blocker is inserted. Then, the 3-D trans-esophageal echocardiographic probe is positioned and the studies described earlier are completed. For hemodynamic monitoring, a thermo-dilution Swan–Ganz™ pulmonary artery catheter (Edwards Lifesciences, Irvine, Calif) is placed via either the subclavian or right internal jugular vein. All intra-vascular cannulations for cardiopulmonary perfusion are done under TEE guidance using the Seldinger guide-wire technique.

While the right neck and shoulder regions are draped for the above instrumentation, our anesthesiologists pass a thin-walled (15-Fr or 17-Fr) Bio-Medicus™ cannula (Medtronic, Minneapolis, MN) via the right internal jugular vein (double-puncture method) into the distal superior vena cava. Thereafter, the patient is placed in a 30° right chest elevated position, prepared, and draped for the operation. Thereafter, the right femoral artery is cannulated using either a 17 or 19-Fr Bio-Medicus™ cannula. For inferior vena caval drainage either 23 or 25-Fr RAP™ femoral venous cannula (Estech, San Ramon, CA) is then passed over a guide-wire into the right atrium. Vacuum-assisted venous drainage is used in all of these operations. Following the left atriotomy and mitral valve exposure, a weighted sucker is placed in the left superior pulmonary vein to scavenge any remaining intra-atrial blood. Carbon dioxide is insufflated continuously through the right robotic arm side-port. At the end of the operation the left atrium is closed by the console surgeon, using running 4-0 PTFE suture, and the heart is de-aired by inflow filling, while ventilating the lungs and applying suction to the aortic root vent.

To monitor adequate limb perfusion during cardiopulmonary bypass, oxygen saturation levels are measured in each leg using the Invos™ System (Somanetics Inc., Troy, MI) When a significant drop in arterial saturation levels occurs in the cannulated leg, we place a wire-directed 5-Fr catheter rapidly into the distal femoral artery and connect it to the arterial perfusion circuit. This generally returns arterial blood saturations toward that of the uninvolved leg. By using this perfusion rescue method for our robotic cases, we have had no ischemia related complications.

Chapter 5 details techniques for both endo-balloon and trans-thoracic cross-clamp aortic occlusion. We prefer the latter method as it has been proven to be safe, reliable, economic, and simple to apply. For myocardial protection we use a systemic blood inflow temperature of 28 °C with cold aortic root cardioplegia. We place the cardioplegia catheter either via endoscopic or direct vision. In our early cases we used intermittent cold blood cardioplegia. Most recently we have used crystalloid Bretschneider’s HTK solution as the cross clamp times can be extended between infusions. Also, this method helps to reduce the chance of introducing aortic root air, which can occur with multiple infusions. We have used retrograde cardioplegia rarely as the majority of non-rheumatic mitral valve patients have a competent aortic valve and non-flow limiting coronary arteries. When infusing cardioplegia, the dynamic retractor should be lowered to avoid aortic valvular incompetence and assure the best myocardial protection.