**7. Surgical procedure**

*Latest Developments in Medical Robotics Systems*

sequential anastomosis techniques [2].

MIDCAB [33], and TECAB [37].

Robotic-assisted CABG is more frequently used to treat total occlusion or ostial

Minimally invasive CABG may also be integrated with a hybrid approach, i.e., achieving simultaneous or delayed complete revascularization with both CABG (usually for the left coronary system) and percutaneous coronary interventions (PCI) (usually for the right coronary system), providing patients with the advan-

Robotic-assisted MIDCAB is one of the most commonly performed roboticassisted CABG procedures around the globe [33]. This is often conducted off-pump and consists of the endoscopic harvesting of the LITA with robotic instrumentation followed by direct anastomosis of the left anterior descending (LAD) artery through a left anterior mini-thoracotomy. Robotic MIDCAB may be preferred in patients with isolated disease of the LAD, or within the framework of hybrid coronary revascularization (HCR) strategy to treat patients with multivessel coronary stenosis along with PCI to all diseased non-LAD vessels [34]. Although robotic MIDCAB is not optimal for hemodynamically unstable patients, patients with limited pulmonary reserve or patients with significantly impaired left ventricular

systolic function, favorable outcomes have been previously reported [35].

Although patient selection for robotic-assisted CABG was initially limited to non-redo patients with isolated single-vessel or double-vessel disease rather than multi-vessel disease and those with preserved ventricular function, inclusion criteria has since then broadened to include also redo patients, provided one internal thoracic artery (ITA) is still adequate for grafting. Studies have demonstrated that the procedure was viable in patients with a history of previous open CABG [36],

In current practice, many patients with a confirmed indication for surgical myocardial revascularization can be deemed as candidates for robotic-assisted CABG. Potential contraindications include acute myocardial ischemia, serious multi-organ dysfunction, severe pulmonary dysfunction, restricted workspace inside the thoracic cavity (e.g., in severe pectus excavatum), thoracic adhesions, and obesity (BMI > 35 kg/m2) [38]. Relative contraindications to TECAB are serious left pleural fibrosis in patients with a history of chronic lung disease or lung surgery. Management with an off-pump approach may not be always feasible in patients with severely impaired lung function and peripheral cardiopulmonary bypass (CPB) support to enhance gas exchange may be considered in these cases. Emergent procedures and patients with advanced left ventricular systolic dysfunction potentially requiring advanced postoperative myocardial support are currently

Team coordination and communication are fundamental aspects to prevent complications in any surgical operation. This is especially important during

robotic-assisted surgery, considering the physical distance between team members. Therefore, we recommend that all team members (consisting of a console surgeon, tableside assistant, anesthesiologist, perfusionist, circulating nurse, and all others who are involved) are equipped with Bluetooth headsets to ensure smooth and

stenosis of the left anterior descending (LAD) artery, and occasionally to treat proximal LAD stenosis which is unsuitable for percutaneous intervention. Roboticassisted CABG is also feasible in the treatment of multivessel disease, though rarely performed, in which both ITAs and a second graft can be used individually or with

tages of each technique in the least invasive manner possible [32].

**80**

ruled out [32].

**6. Anesthetic approach**

effective communication.

### **7.1 Patient positioning**

Some preliminary steps including patient set up, cardiopulmonary perfusion, placement of the ports, and robotic-assisted harvesting of LITA are in the same manner for both robotic-assisted CABG surgeries. While the MIDCAB procedure continues with de-novo incision after LITA harvesting for making a direct handsewn anastomosis between the LITA and the coronary target, the TECAB procedure continues with robotic-assisted coronary anastomosis [31].

After the left lung is deflated, three robotic ports are placed into the left thoracic cavity under direct view. First, the camera port is located in the left fourth intercostal space in the anterior axillary line. The right and left robotic instrument ports are placed under endoscopic visualization in the second and sixth intercostal spaces, respectively, in alignment with the camera port.

The robotic-assisted anastomosis part of the TECAB surgery requires two additional ports which should be placed after robotic ITA harvesting and graft preparation. A 12-mm 4th robotic port is used to insert the Endo-wrist™ stabilizer, placed in the left subcostal space, medial side of the midclavicular line. And finally, to deliver the Cardica Flex A™ anastomotic device, a 15-mm port (Ethicon Surgical, Somerville NJ) is inserted in the 2nd intercostal space on the left midclavicular line.

After the ports placed, the table is lowered and tilted 10° to the right, and the da Vinci Si system (Intuitive Surgical, Sunnyvale, California, United States) is docked with the robotic cart, which is generally located at approximately 60° angle to the table from the right side. This positioning is to decrease the interference between the robotic arms.

Continuous warm humidified CO2 insufflation should be maintained to properly dilate the surgical area and provide sufficient pleural workspace. Intrathoracic pressure must be kept within 8–12 mmHg not to compromise hemodynamic stability. Air insufflation systems should be used at low levels since excessive use of insufflation may cause endothelial damage. We recommend maintaining the CO2 insufflation settings while entering the right thoracic cavity for BITA harvesting. Of note, using two CO2 insufflation is convenient in TECAB surgery to protect the vascular structures and heart itself from injury as a result of a sudden loss of pressure.

#### **7.2 Cardiopulmonary perfusion and myocardial protection**

Robotic-assisted CABG can be executed either on an arrested or beating heart. Whether the operation will be performed with the arrested or beating heart approach is decided cautiously considering the vascular status of the patient since the arrested heart approach may provide a better quality of anastomosis. CBP support is obligatory in the arrested heart approach. But it is not the only case that requires CBP support. It can be also used in the beating heart approach to improve poor blood gas exchange and in patients with multiple vessel disease additionally to badly constructed vascular status [2].

Considering arrested heart or beating heart surgery in need of hemodynamic or pulmonary support, the peripheral CPB method is usually the chosen one. The CPB support during TECAB is considerably low (less than 2%) and most of which used to improve gas exchange rate during single lung ventilation [31].

Since peripheral CPB support is recommended in case CPB is needed, femoral vessels should be prepared. A transverse left inguinal incision is made above the inguinal ligament to expose the femoral artery and vein. Firstly, a 4–0 polypropylene purse-string suture is implanted in each vessel which is followed by tourniquet application. Then, the introduction of a perfusion cannula with a sidearm (21-F or 23-F) into the femoral artery is underway. At last, cannulation of the femoral vein with a 25-F venous cannula is performed.

IntraClude™ balloon occlusion catheter (Edwards Lifesciences, Irvine, CA, USA) or a mechanical cross-clamp (e. g. Chitwood™, Scanlon International, Minneapolis, MN, USA) with antegrade cardioplegia are the preferred tools to be used during aortic cross-clamping and cardioplegia delivery. Because of the reason that pulmonary artery interposition makes cross-clamping the aorta from the left chest to be technically challenging, balloon occlusion catheter remains to be the preferred one.

TEE guidance is essential during the insertion of the IntraClude™ balloon occlusion catheter towards the aortic root. The balloon should be placed above the sino-tubular junction, and well below the brachiocephalic trunk. Antegrade, cold blood cardioplegia should be administered repeatedly according to the chosen cardioplegia solution.

#### **7.3 ITA harvesting**

After the endoscopic camera (30-degree up) is inserted, monopolar curved scissors are equipped to the right arm while Maryland bipolar forceps are equipped to the left one. Then dissection and reflection of the pericardial fat pad are performed. Pinpoint determination of the opening site of the pericardium is decided according to the grafting approach, since the pericardiotomy should be performed anterior to the phrenic nerve and towards the apex of the heart for LAD targets, and

**83**

*Robotic Coronary Artery Bypass Grafting: History, Current Technique, and Future Perspectives*

pericardium should be entered posterior to the phrenic nerve for circumflex marginal coronary targets. In addition, a small-scaled pericardial incision posterior to the phrenic nerve can both help drainage of the pericardial space post-operatively as well as in our belief it helps to prevent postoperative pericarditis. Since the protection of the phrenic nerve is of vital importance, care should always be taken to avoid

After reaching the surface of the epicardium, the angiogram becomes particularly useful to point out the correct coronary targets. Following the description of the targets for endoscopic grafting, attention is directed towards the ITA(s).

The two ITAs are adjacent to each other and to the heart from the endothoracic

Due to the lack of tactile feedback, excess tension should be avoided, and extra care should be taken to avoid damaging the ITAs. ITA harvesting begins from the proximal side, until its origin from the subclavian artery, to enable it to utilize its entire length. The harvesting is preferably performed as a skeletonized technique by the dissection of the artery from the fascia, intercostal muscles, and the encircling tissues to take maximum advantage of the length of the artery and also to profit from higher flow capacity [42]. This technique also assists in maneuvering the graft within the thoracic cavity and also paves the way for the assessment of the endoscopic transit-time Doppler flow. Despite the advantages of this technique, many surgeons, especially those at an earlier phase of their robotics training, still goes for

If the right internal thoracic artery (RITA) is to be used, it should also be the first to be harvested. Otherwise, the left thoracic artery (LITA) should be chosen without the opening of the right pleura. For both conduits, the dissection procedure

At the beginning of the RITA harvesting procedure, the finest view while dissecting of the substernal anterior mediastinal fibro-fatty tissue and during entry into the right thoracic space is given by a 0-degree robotic endoscope. After the dissection is done, the RITA should be harvested using a 30-degree (focusedup) scope. When instruments are guided into the right pleural space, it is of vital importance to prevent physical contact with the heart. Careful maneuvers should be undertaken in order to position the cameras safely near to the right pleural workspace, and the instruments should first be spotted by a direct vision from the

The endothoracic fascia and the transverse thoracic muscle are divided to uncover the vessel while harvesting RITA. For the monopolar spatula and micro bipolar forceps (20 W), a low electro-cautery setting is used to cauterize narrow vessel branches, while the larger ones should be divided with robotically applied

The Endo-Wrist stabilizer is used to compress the anterior mediastinal tissue to optimally harvest the proximal and distal sections of the RITA. This instrument is extremely useful in TECAB surgery to help stabilize the target during the anastomosis, whether it is done on a beating or arrested heart, but it is also practical during a conduit harvesting process since it allows routine BITA harvesting regardless of the anatomical variations between the patients. It is inserted through a 12-mm subcostal 4th robotic port placed between the xiphoid process and the midclavicular line as mentioned before. When docking the fourth robotic arm a "setup joint" adjustment towards cephalic direction is recommended in order to avoid external

viewpoint than is commonly appreciated, considering the greater majority of surgeons only encountered them in open CABG procedures when the sternum is widely separated by a midline sternotomy incision. Thereby, either of the ITA can be used as an in-situ conduit to graft the LAD and high marginal branches.

*DOI: http://dx.doi.org/10.5772/intechopen.99399*

injury during pericardial manipulation.

the ITAs as pedicled grafts.

left pleural area and then removed from there.

is identical.

metal clips.

conflicts between robotic arms.

### *Robotic Coronary Artery Bypass Grafting: History, Current Technique, and Future Perspectives DOI: http://dx.doi.org/10.5772/intechopen.99399*

pericardium should be entered posterior to the phrenic nerve for circumflex marginal coronary targets. In addition, a small-scaled pericardial incision posterior to the phrenic nerve can both help drainage of the pericardial space post-operatively as well as in our belief it helps to prevent postoperative pericarditis. Since the protection of the phrenic nerve is of vital importance, care should always be taken to avoid injury during pericardial manipulation.

After reaching the surface of the epicardium, the angiogram becomes particularly useful to point out the correct coronary targets. Following the description of the targets for endoscopic grafting, attention is directed towards the ITA(s).

The two ITAs are adjacent to each other and to the heart from the endothoracic viewpoint than is commonly appreciated, considering the greater majority of surgeons only encountered them in open CABG procedures when the sternum is widely separated by a midline sternotomy incision. Thereby, either of the ITA can be used as an in-situ conduit to graft the LAD and high marginal branches.

Due to the lack of tactile feedback, excess tension should be avoided, and extra care should be taken to avoid damaging the ITAs. ITA harvesting begins from the proximal side, until its origin from the subclavian artery, to enable it to utilize its entire length. The harvesting is preferably performed as a skeletonized technique by the dissection of the artery from the fascia, intercostal muscles, and the encircling tissues to take maximum advantage of the length of the artery and also to profit from higher flow capacity [42]. This technique also assists in maneuvering the graft within the thoracic cavity and also paves the way for the assessment of the endoscopic transit-time Doppler flow. Despite the advantages of this technique, many surgeons, especially those at an earlier phase of their robotics training, still goes for the ITAs as pedicled grafts.

If the right internal thoracic artery (RITA) is to be used, it should also be the first to be harvested. Otherwise, the left thoracic artery (LITA) should be chosen without the opening of the right pleura. For both conduits, the dissection procedure is identical.

At the beginning of the RITA harvesting procedure, the finest view while dissecting of the substernal anterior mediastinal fibro-fatty tissue and during entry into the right thoracic space is given by a 0-degree robotic endoscope. After the dissection is done, the RITA should be harvested using a 30-degree (focusedup) scope. When instruments are guided into the right pleural space, it is of vital importance to prevent physical contact with the heart. Careful maneuvers should be undertaken in order to position the cameras safely near to the right pleural workspace, and the instruments should first be spotted by a direct vision from the left pleural area and then removed from there.

The endothoracic fascia and the transverse thoracic muscle are divided to uncover the vessel while harvesting RITA. For the monopolar spatula and micro bipolar forceps (20 W), a low electro-cautery setting is used to cauterize narrow vessel branches, while the larger ones should be divided with robotically applied metal clips.

The Endo-Wrist stabilizer is used to compress the anterior mediastinal tissue to optimally harvest the proximal and distal sections of the RITA. This instrument is extremely useful in TECAB surgery to help stabilize the target during the anastomosis, whether it is done on a beating or arrested heart, but it is also practical during a conduit harvesting process since it allows routine BITA harvesting regardless of the anatomical variations between the patients. It is inserted through a 12-mm subcostal 4th robotic port placed between the xiphoid process and the midclavicular line as mentioned before. When docking the fourth robotic arm a "setup joint" adjustment towards cephalic direction is recommended in order to avoid external conflicts between robotic arms.

*Latest Developments in Medical Robotics Systems*

badly constructed vascular status [2].

with a 25-F venous cannula is performed.

cardioplegia solution.

**7.3 ITA harvesting**

the robotic arms.

with the robotic cart, which is generally located at approximately 60° angle to the table from the right side. This positioning is to decrease the interference between

Continuous warm humidified CO2 insufflation should be maintained to properly dilate the surgical area and provide sufficient pleural workspace. Intrathoracic pressure must be kept within 8–12 mmHg not to compromise hemodynamic stability. Air insufflation systems should be used at low levels since excessive use of insufflation may cause endothelial damage. We recommend maintaining the CO2 insufflation settings while entering the right thoracic cavity for BITA harvesting. Of note, using two CO2 insufflation is convenient in TECAB surgery to protect the vascular structures and heart itself from injury as a result of a sudden loss of pressure.

Robotic-assisted CABG can be executed either on an arrested or beating heart.

Considering arrested heart or beating heart surgery in need of hemodynamic or pulmonary support, the peripheral CPB method is usually the chosen one. The CPB support during TECAB is considerably low (less than 2%) and most of which used

Since peripheral CPB support is recommended in case CPB is needed, femoral vessels should be prepared. A transverse left inguinal incision is made above the inguinal ligament to expose the femoral artery and vein. Firstly, a 4–0 polypropylene purse-string suture is implanted in each vessel which is followed by tourniquet application. Then, the introduction of a perfusion cannula with a sidearm (21-F or 23-F) into the femoral artery is underway. At last, cannulation of the femoral vein

IntraClude™ balloon occlusion catheter (Edwards Lifesciences, Irvine, CA, USA) or a mechanical cross-clamp (e. g. Chitwood™, Scanlon International, Minneapolis, MN, USA) with antegrade cardioplegia are the preferred tools to be used during aortic cross-clamping and cardioplegia delivery. Because of the reason that pulmonary artery interposition makes cross-clamping the aorta from the left chest to be technically challenging, balloon occlusion catheter remains to be the preferred one. TEE guidance is essential during the insertion of the IntraClude™ balloon occlusion catheter towards the aortic root. The balloon should be placed above the sino-tubular junction, and well below the brachiocephalic trunk. Antegrade, cold blood cardioplegia should be administered repeatedly according to the chosen

After the endoscopic camera (30-degree up) is inserted, monopolar curved scissors are equipped to the right arm while Maryland bipolar forceps are equipped to the left one. Then dissection and reflection of the pericardial fat pad are performed. Pinpoint determination of the opening site of the pericardium is decided according to the grafting approach, since the pericardiotomy should be performed anterior to the phrenic nerve and towards the apex of the heart for LAD targets, and

Whether the operation will be performed with the arrested or beating heart approach is decided cautiously considering the vascular status of the patient since the arrested heart approach may provide a better quality of anastomosis. CBP support is obligatory in the arrested heart approach. But it is not the only case that requires CBP support. It can be also used in the beating heart approach to improve poor blood gas exchange and in patients with multiple vessel disease additionally to

**7.2 Cardiopulmonary perfusion and myocardial protection**

to improve gas exchange rate during single lung ventilation [31].

**82**

When executing the mediastinal fat retraction with the Endo-Wrist stabilizer, care must be taken to secure that suited proximal dissection of the RITA is accomplished and adequate conduit length is provided. The 0-degree scope is ideally used to harvest the proximal RITA; the artery should be dissected up till the first intercostal branches are uncovered; then several metal clips should be used to divide the medial right internal thoracic vein. In order to widen the anteroposterior space especially in patients with narrow space between the sternum and the heart and thereby decrease the risk of instrument-induced arrhythmias, the stabilizer is then positioned on the epicardial surface while dissecting the caudal extremity of the RITA. Once the RITA is almost entirely liberated but not distally divided from the encircling tissue, attention is drawn to the LITA, which is harvested likewise as mentioned before.

The conduits are prepared with intraluminal papaverine solution injection after the harvesting of both ITAs from the loose areolar tissue is completed over their total length. A bulldog clamp is placed on the proximal RITA after heparinization. To evaluate sufficient flow through the conduit, the distal end of the RITA was occluded by a metal clip, and partially transected only the proximal site of this clip with the help of robotic Potts scissors afterward. Meanwhile, a syringe of 1:20 diluted papaverine solution connected to a 20-G Perifix® epidural catheter (B. Braun, Melsungen, Germany) is operated by the table-side assistant via the working port and then inserted tenderly by the console surgeon into the lumen of the RITA. Papaverine is injected as the catheter is removed. The table-side assistant should extract arterial blood before infusing the papaverine to confirm the correct intra-luminal catheter location. The catheter should then be slowly retrieved, and immediately after catheter removal, the RITA is distally clipped. For LITA, the same procedure is repeated.

#### **7.4 Coronary target(s) preparation**

If robotic-assisted MIDCAB surgery is the selected approach, this step continues with removing the robotic instruments and ports and expanding the camera port incision to a 5-cm left anterior mini-thoracotomy to provide direct access to the selected coronary targets, while TECAB surgery continues with robotic assistance in the rest of the procedure thereby does not need a wider thoracotomy incision. The retractors are used in Robotic-assisted MIDCAB to provide a better view similar to regular MIDCAB surgery. A pericardiotomy is performed through thoracotomy incision, which is applied anteromedially in the direction of the apical part of the heart, imitating the orientation of the LAD thus allowing the ITA to enter the pericardial space without any twist or torsion afterward. After the pericardiotomy, the LAD is exposed and can be stabilized with the help of external vacuum-assisted or pressure-assisted systems. After the coronary target preparation is finished, a direct hand-sewn graft-coronary target anastomosis is applied through the thoracotomy incision in MIDCAB surgery.

TECAB surgery, which stands out among all the surgical myocardial revascularization strategies due to its minimally invasive nature, requires two additional ports which should be placed in this stage of the procedure. A 12-mm 4th robotic port for the Endo-wrist™ stabilizer and finally, a 12 mm or 15-mm working port for coronary anastomosis instead of a de-novo thoracotomy incision.

With the help of the Endo-Wrist stabilizer, the coronary target(s) is stabilized and then exposed. Proper exposure is served by using low cautery energy with gentle opening of the overlying epicardium, which in our belief is more beneficial than sharp dissection to obtain better hemostasis in an endoscopic workspace.

**85**

before coronary occlusion [43].

*Robotic Coronary Artery Bypass Grafting: History, Current Technique, and Future Perspectives*

The coronary target is then proximally encircled with a silastic snare Saddleloop™ (Quest Medical, Inc., Allen, TX, USA). To limit the possible venous bleeding at the coronary target sites, the silastic snare application is performed before the delivery of systemic heparinization and dividing the conduits. Upon the completion of coronary target preparation, the patient is heparinized with a specific target of activated clotting time (ACT) for each procedure acting as 300 s for MIDCAB and off-pump TECAB, while should be above 420 s for on-pump-TECAB.

**7.5 Robotic-assisted coronary anastomosis, device-driven fashion**

Contrary to robotic-assisted MIDCAB surgery, the coronary target anastomosis part of TECAB surgery is also completed endoscopically. There are two techniques for robotic-assisted anastomosis and applications differ depending on preference. If device-driven anastomosis is to be made, a 15 mm working port is required to insert C-Port Flex A system; on the other hand, if the hand-sewn technique is to be used, a 12 mm working port is required to embed the coronary shunts and sutures (Ethicon

A 30-degree scope is used for better visualization. To begin with the devicedriven technique, the left and right robotic arms are equipped with Black Diamond forceps. The stabilizer at the 4th port is replaced with a DeBakey forceps and the 15 mm working port is loaded with the Flex A system to perform the automated

The Flex A device is inserted along with its neutral position which points to the diaphragm as the anvil facing heart and cartridge facing sternum and held by the DeBakey forceps. Then it is rotated in a way that now cartridge faces down while the anvil faces the sternum. Later on, the device is moved vertically to a position that faces the camera. In order to inspect and trim encircling tissue, ITA is also oriented and positioned along with the device. The placement of LITA inside the cartridge can now be ready to complete after the 10-mm linear arteriotomy. Following the placement of heels of the arteriotomy to the designated sites on the cartridge by two Black Diamond forceps, tableside assistant lowers the piercer onto the heel clip and fixates the heel of LITA onto the cartridge. During the next step, which is lowering the shield guard, slight bending of the guard can enhance the hood of the anastomosis. Then, both sides of the heel are positioned to the contrary sides of the cartridge to match with staple bays. During this placement, it is of vital importance that each staple bay is correctly matched with LITA tissue and there should be no folds in the LITA after it is properly positioned. In order to achieve this, firstly tableside assistant lowers the right-wing guard. Then, before lowering the left-wing guard, the assistant should also remove the piercer to fixate LITA in the proper place. Lowering both of the wing guards and fixation of LITA to its proper place marks the loading of the conduit so that the device can now be moved back to its neutral position and placed nearby to the target vessel on the pericardium.

The 4th port is loaded with the Endo-Wrist stabilizer once again to stabilize the coronary target. The silastic snare that encircles the coronary target which previously placed before is now tightened and hemodynamic responses and ECG alterations are observed. ST-segment elevations are tolerated since it's not necessarily a proof of ischemia but can be referred to alterations in signal detection because of the physical displacement of the heart unless followed with hemodynamic compromise. Ischemic preconditioning might be beneficial to prepare the myocardium

After the coronary flow is blocked by tightening the silastic snare, a small coronary arteriotomy in the core of a previously placed CV-8 Gore-Tex suture (Gore Medical, Flagstaff, Ariz) is performed by an endo-knife (Snap-Fit; Intuitive

*DOI: http://dx.doi.org/10.5772/intechopen.99399*

Surgical, Somerville, NJ, USA).

coronary anastomosis.

The coronary target is then proximally encircled with a silastic snare Saddleloop™ (Quest Medical, Inc., Allen, TX, USA). To limit the possible venous bleeding at the coronary target sites, the silastic snare application is performed before the delivery of systemic heparinization and dividing the conduits. Upon the completion of coronary target preparation, the patient is heparinized with a specific target of activated clotting time (ACT) for each procedure acting as 300 s for MIDCAB and off-pump TECAB, while should be above 420 s for on-pump-TECAB.
