Nearly all surgical disciplines have developed endoscopic

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1 New Drugs and Technologies Robotically Assisted Totally Endoscopic Coronary Bypass Surgery Johannes Bonatti, MD; Thomas Schachner, MD; Nikolaos Bonaros, MD, PhD; Eric J. Lehr, MD, PhD; David Zimrin, MD; Bartley Griffith, MD Nearly all surgical disciplines have developed endoscopic operations over the last 2 decades that have become the standard of care. In cardiac surgery and specifically for coronary artery bypass grafting (CABG), the adoption of minimally invasive techniques was challenging for the following reasons: First, most procedures are already complex, and endoscopic approaches further increase the degree of complexity; second, the cardiac surgery community had until recently no endoscopic surgical tradition; and finally, early attempts to perform CABG with the use of conventional thoracoscopic instrumentation failed completely. 1 Cardiac surgeons have standardized open operations for acquired heart disease, and despite low mortality and excellent results, CABG outcomes are heavily scrutinized. Consequently, the bar has been raised for any new competing technology, which has slowed its adoption. Robotic surgical technology was developed with the idea of performing remote operations and procedures in difficult spaces. These machines allow surgical maneuvers to be performed by instruments on robotic arms that are controlled by the operator from a console situated away from the operating table. This technology is well suited for completely endoscopic suturing inside the chest. In 1998, Loulmet et al 2 performed the world s first totally endoscopic coronary artery bypass (TECAB) procedure using robotic assistance. The patient who received a single left internal mammary artery (IMA) to left anterior descending artery graft remains alive and free from angina 12 years postoperatively. During subsequent years, development has been slow but significant. TECAB developed from a single-vessel procedure to complex endoscopic robotic multivessel revascularization (Figure 1). The third generation of surgical telemanipulators is now available, with technological improvements in the areas of high-definition video, robotic arm mobility, instrument reach, surgeon comfort, and capability for intraoperative surgical endoscopic teaching with a dual-console system. 3 This review describes the current techniques that are applied to robotically assisted CABG and reports on overall clinical results of variations on approaches. A slow stepwise approach to learning completely endoscopic techniques is mandatory, 4,5 and a stable, dedicated team is vitally important for successful procedure implementation. Some pioneering groups failed and abandoned their programs because such steps were not taken and because a stable team could not be established. Preliminary Steps Robotic Internal Mammary Artery Harvesting The initial clinical step for programs wishing to develop a robotic coronary surgery program is IMA takedown and completion of CABG through sternotomy or minithoracotomy. Before this step is implemented, IMA harvesting can be practiced in dry laboratory models, in the human cadaver, and in vivo in pigs or dogs. Both pedicled and skeletonized harvesting techniques can be applied, with the latter offering the advantages of better graft length and easier graft handling. Robotic IMA harvesting is performed with the patient under general anesthesia with a double-lumen endotracheal tube to allow single-lung ventilation. With the left lung collapsed, a 12-mm camera port is usually placed into the left fifth intercostal space on the anterior axillary line. Additional 8-mm instrument ports are inserted into the left third and seventh intercostal spaces between the midclavicular line and the anterior axillary line for the instrument arms. Insufflation of CO 2 into the chest enhances intrathoracic working space. The IMA is localized, and the endothoracic fascia is removed from the artery to provide adequate exposure of the IMA and its concomitant veins. IMA harvesting is then performed with the use of electrocautery at low energy levels. After systemic heparinization, the graft is clipped distally and detached from the thoracic wall. Distal preparation can be performed elegantly with the use of the robotic instruments. Free flow is assessed, and topical vasodilators can be applied endoscopically. Both the left and the right IMAs can be harvested after port placement from the patient s left side. For access to the right IMA, the retrosternal tissue is dissected, and the right pleura is opened. Table 1 summarizes the operative time and learning curve for robotic IMA harvesting in published articles. 2,6 11 From the Division of Cardiac Surgery, Department of Surgery (J.B., E.J.L., B.G.), and Division of Cardiology, Department of Medicine (D.Z.), University of Maryland School of Medicine, Baltimore; and Department of Cardiac Surgery, Innsbruck Medical University, Innsbruck, Austria (T.S., N.B.). Correspondence to Johannes Bonatti, MD, FETCS, Department of Surgery/Division of Cardiac Surgery, University of Maryland at Baltimore, 22 S Greene St, N4W94, Baltimore, MD jbonatti@smail.umaryland.edu (Circulation. 2011;124: ) 2011 American Heart Association, Inc. Circulation is available at DOI: /CIRCULATIONAHA

2 Bonatti et al Robotic TECAB 237 Figure 1. Development of robotic totally endoscopic coronary artery bypass grafting from 1998 to Note the improvement in performance from single bypass grafting only to complex surgical endoscopic and hybrid interventions. AH indicates arrested heart; BH, beating heart; BMS, bare metal stent; and DES, drugeluting stent. Robotically Assisted Coronary Artery Bypass Grafting Through Minithoracotomy Before proceeding to TECAB, some groups feel more comfortable with an additional preliminary step: The IMAs are harvested robotically and followed by graft to coronary artery anastomoses under direct vision through a minithoracotomy. The most commonly used terms for robotically assisted CABG through minithoracotomy are minimally invasive direct coronary artery bypass, single-vessel small thoracotomy, multivessel small thoracotomy, and robotically assisted coronary artery bypass. The IMA harvest is performed as described above, after which the pericardial fat pad is removed, and the pericardium is opened. The robotic endoscope is helpful in localizing the coronary target vessels, and can also assist in identification of the correct intercostal space through which the target vessel is approached for anastomosis, although the minithoracotomy is most commonly performed in the fourth left intercostal space. Small thoracotomy retractors or less traumatic soft tissue retractors enhance exposure of the target vessel and allow use of standard surgical microinstrumentation for direct suturing by hand. Apical suction positioning devices and suction stabilizers are placed through the thoracotomy or through additional small port incisions to enhance exposure of targets on the circumflex and right coronary artery system and for immobilization of the target vessel. Table 1. Published Series of Robotic IMA Harvesting Author and Reference Cases IMA Harvesting Time, min End of Steep Part of Learning Curve, Cases Loulmet et al Falk et al Dogan et al Bonatti et al Reuthebuch et al Kiaii et al Oehlinger et al (19 180) 15 IMA indicates internal mammary artery. Minithoracotomy approaches can be challenging, especially in obese patients, and only a keyhole view of the target vessel is granted rather than the full visual immersion into the chest that is available in robotic TECAB. In addition, minithoracotomies appear to be more painful than a port-only approach, especially if rib spreading is involved. Prolonged rib spreading for minithoracotomy may increase the risk of wound infection, especially in obese and patients with diabetes mellitus. 12 In contrast, we have observed an overall rate of deep thoracic wound infection of only 2 in 410 TECAB patients (0.5%), with events occurring only in patients who required conversion to open sternotomy. The outcomes published for robotically assisted minimally invasive direct CABG approaches (Table 2) show no perioperative mortality and low complication rates Open Chest Robotic Anastomosis Robotic surgical devices were designed to enable precise microsurgical maneuvers inside the chest. Robotically assisted coronary microanastomoses are feasible and reproducible with training and practice. We demonstrated previously that suturing coronary anastomoses on inanimate porcine hearts with robotic techniques is an effective training model. 18 Such models were required in early Food and Drug Administration studies of robotic surgery 4 and should be part of the development process for any clinical program considering robotic CABG. Another early study by our group demonstrated that initial experience with robotic suturing of bypass anastomoses via midline sternotomy as part of a standard CABG procedure is a reasonable step to enable a safe subsequent totally endoscopic approach. 5 Bolton and Connally 19 described 10 such anastomoses performed on the beating heart through sternotomy or small thoracotomy. Two anastomotic failures were corrected immediately. The authors point out the feasibility and relative safety of this approach. Postoperative hospital stay was 2.8 days, and a stress echocardiogram was normal or improved in 7 of 8 patients restudied at 3 months.

3 238 Circulation July 12, 2011 Table 2. Results of Robotically Assisted Coronary Artery Bypass Grafting on the Beating Heart Through Minithoracotomy Author and Reference Cases Conversion Perioperative Mortality Revision for Bleeding Stroke Renal Failure Length of Stay, d Kiaii et al Derose et al (2 14) Subramanian et al % discharged within 1 d Turner et al Srivastava et al Kon et al Poston et al Total, n (%) 460 9/360 0/460 12/345 1/378 3/325 (2.5) (0.0) (3.5) (0.3) (0.9) Completely Endoscopic Approaches Totally Endoscopic Coronary Artery Bypass on the Arrested Heart The world s first TECAB operation was performed with bifemoral cannulation for cardiopulmonary bypass and endoballoon occlusion of the ascending aorta for delivery of cardioplegia. 2 A Food and Drug Administration trial for TECAB on the arrested heart (AHTECAB) has been published, confirming the feasibility and safety of this approach. 4 Efficiency of AHTECAB is enhanced when endoscopic IMA harvesting and femoral cannulation are performed concurrently by 2 surgeons, 1 at the operating table and 1 at the robotic console. An endoaortic occlusion balloon is advanced into the aortic root under transesophageal echocardiographic guidance. After the IMAs are prepared, the pericardial fat pad is resected, and the pericardium is opened. Cardiopulmonary bypass is initiated; while the patient is systemically cooled, the endo-occlusion balloon is inflated in the ascending aorta, isolating the coronary arteries from the systemic circulation (just as with the application of an aortic cross-clamp in open procedures). Cardioplegic arrest can be induced with antegrade high-potassium, blood cardioplegia solution delivered via the aortic root through a distal channel of the endoballoon catheter. Suturing the CABG anastomosis on the arrested heart is very precise because the heart is still, the surgeon is immersed in the operative field, and the robotic instruments are natural extensions of the surgeons hands. The current suturing technique does not differ significantly from open CABG. In most cases, however, the robotic surgeon performs the suture in a solo fashion, without countertraction by an assistant. Cardioplegic arrest times are currently prolonged compared with open sternotomy cases, and few data exist on the likelihood of increased myocardial injury arising from these procedures. We have shown previously that for cardiac arrest times of up to 3 hours, myocardial enzyme release is comparable to previous studies on open CABG and that prolonged arrest times in TECAB did not lead to significant reduction of postoperative left ventricular ejection fraction. 20 The IMA to coronary artery anastomoses are performed with the use of a double-armed 7-cm polypropylene suture, U clips, or anastomotic devices. Single, double, 21 and triple AHTECAB are feasible. Our team at the University of Maryland has performed the first triple-vessel AHTECAB worldwide. 22 Sequential bypass grafts 7 and Y grafts can be constructed in completely endoscopic fashion. Another major advantage of AHTECAB compared with TECAB on the beating heart (BHTECAB) is that the completely flaccid arrested heart can be rotated easily for access to the circumflex coronary artery system without concern for hemodynamic insufficiency. Intrathoracic workspace is enhanced significantly compared with beating heart techniques without extracorporeal circulation because both lungs can be deflated during cardiopulmonary bypass. We have described exposure techniques for the back wall of the heart with the use of suction stabilization. 23 Table 3 lists available AHTECAB publications with clinical results. No mortality was observed. The conversion rate to larger thoracic incisions dropped from the 25% range in early series 2,7,24 26 to a current cumulative total of 16.4%. Revision rates for bleeding are higher than in open CABG and higher than in series on BHTECAB. An impaired coagulation system, as a side effect of cardiopulmonary bypass, is certainly a contributing factor. With increased experience, enhanced prevention and management of porthole bleeding has greatly reduced this complication. Rates of stroke and renal failure in the published series describing AHTECAB series are very low. Few data are available in the current literature concerning postoperative wound infection, although the Food and Drug Administration AHTECAB trial reported a 6% groin infection rate. 4 Totally Endoscopic Coronary Artery Bypass on the Beating Heart BHTECAB without any use of extracorporeal circulation is often regarded as the ultimate goal. The appeal of off-pump CABG has lessened, however, because of recent reports questioning its advantage over conventional CABG 27 in the open setting. One-year cognitive function is not different between on- and off-pump CABG. 28 Nevertheless, even for surgeons who favor AHTECAB, familiarity with BHTECAB techniques is mandatory for managing patients with contraindications to remote access perfusion and balloon endoocclusion of the ascending aorta (eg, severe peripheral vascular disease, ascending aortic dilatation). Kappert et al 29

4 Bonatti et al Robotic TECAB 239 Table 3. Results of Totally Endoscopic Coronary Artery Bypass Grafting Using Cardiopulmonary Bypass and Cardioplegia Author and Reference Cases Conversion Perioperative Mortality Revision for Bleeding Stroke Renal Failure Length of Stay, d Loulmet et al (mean) Dogan et al Bonatti et al (mean of 2 groups) Falk et al (5 20) Argenziano et al de Canniere et al Bonatti et al (mean of 4 groups) Total, n (%) /390 0/390 21/298 2/276 1/238 (16.4) (0.0) (7.1) (0.7) (0.4) reported a small series of successful BHTECAB from Dresden, Germany. BHTECAB has become feasible, and was refined with the availability of adequate endoscopic suction stabilizers. The second and third generations of robotic systems (davinci S and Si) include a suction stabilizer that can be inserted as a robotic instrument and is controlled by the surgeon from the console. After IMA harvesting and exposure of the heart, the endostabilizer is brought into the chest through a subcostal port, which is docked to the fourth arm of the robotic system. The target vessel is immobilized and snared with Silastic tapes. An endoluminal shunt can be inserted. Polypropylene or polytetrafluoroethylene suture, U clips, and anastomotic devices have all been used to construct grafts to coronary artery anastomoses. Technically, the anastomoses in BHTECAB are challenging because the movement of the heart is also magnified. Table 4 lists published clinical results. 25,29 33 The conversion rate to larger thoracic incisions has dropped from 32% in the initial series 25 to 18%. Perioperative mortality is 0.6% and appears slightly higher than in AHTECAB. Hospital length of stay, however, is slightly shorter. Similar to AHTECAB, the rate of major complications such as stroke and renal failure is 0.5%. Prospective randomized trials or retrospective matched comparisons of TECAB with standard on-pump CABG or off-pump CABG are currently unavailable. The authors believe that a comprehensive program for TECAB should offer both beating and arrested heart methods to tailor the procedure to the patient s specific needs. Conversion to open procedures should be regarded primarily as a second option and not as failure. Pump-Supported Beating Heart Totally Endoscopic Coronary Artery Bypass Endoscopic placement of coronary bypass grafts to the lateral and back walls of the heart is technically very challenging without cardiopulmonary bypass. Few data, however, are available to assess outcomes of pump-assisted BHTECAB. In 2008, our group began to use cardiopulmonary bypass support for robotic BHTECAB. Both femoral and axillary approaches for arterial cannulation have been used. The primary advantage of axillary artery compared with femoral artery cannulation is antegrade perfusion of the descending and abdominal thoracic aorta and the aortoiliac arterial level, thus lowering the risk of retrograde cerebral embolization and retrograde aortic dissection. 34 Cardiopulmonary bypass dramatically reduces the technical difficulty of BHTECAB by unloading the heart and permitting bilateral lung deflation, which leads to greater working space within the closed chest. Even prophylactic cannulation and cardiopulmonary bypass standby can help in managing the following technical difficulties: myocardial ischemia and arrhythmia during target vessel occlusion, hemodynamic instability during endoscopic exposure of the bypass grafting targets, bleeding from the target vessel, and organ injuries during insertion of robotic instruments. Crash conversions to cardiopulmonary bypass in Table 4. Results of Totally Endoscopic Coronary Artery Bypass Grafting on the Beating Heart Without Heart-Lung Machine Use Author and Reference Cases Conversion Perioperative Mortality Revision for Bleeding Stroke Renal Failure Length of Stay, d de Canniere et al Kappert et al Boyd et al Loisance et al Srivastava et al /93 0 1/ Srivastava et al Total, n (%) /488 3/488 3/334 1/334 2/334 (18.4) (0.6) (0.9) (0.3) (0.6)

5 240 Circulation July 12, 2011 Table 5. Operative Times in Published Series of Robotically Assisted Coronary Artery Bypass Grafting LIMA-LAD Method and Author Cases Anastomosis, min Total Operating Room Time, min SVST, MVST, RACAB Subramanian (multivessel) Turner and Sloan (first 10 cases) 232 (second 10 cases) Srivastava et al AHTECAB Argenziano et al (single vessel) Falk et al (15 34) 330 ( ) Dogan et al Bonatti et al (23 66) 366 (including angiography) Bonatti et al (including angiography) BHTECAB Kappert et al (single vessel) Srivastava et al (single and multivessel) Srivastava et al (single vessel) LIMA indicates left internal mammary artery; LAD, left anterior descending coronary artery; SVST, single-vessel small thoracotomy; MVST, multivessel small thoracotomy; RACAB, robotically assisted coronary artery bypass grafting; AHTECAB, arrested heart totally endoscopic coronary artery bypass; and BHTECAB, beating heart totally endoscopic coronary artery bypass. off-pump CABG through sternotomy have been shown to carry a very high mortality risk, in the 10% range, 35 even with full exposure of the heart and direct access for aortic and right atrial cannulation. Resuscitation and emergent groin cannulation are even more difficult in BHTECAB because the robotic arms are docked to the patient. One drawback of a pump run during endoscopic BHTECAB is port-hole bleeding. In our experience, significant diffuse bleeding occurred when a standard heart-lung machine is used. This problem has been controlled with application of minimally invasive extracorporeal circulation. Some of these systems can be run at activated clotting time levels in the 300-second range, thereby dramatically reducing the intraoperative oozing from the portholes. 36 Time Requirements TECAB procedures are complex, and consequently, along with other factors, can take longer than open CABG. Table 5 lists published operative times. Note that most of these series include a significant percentage of learning curve cases. In our last 50 cases of totally endoscopic left IMA to left anterior descending artery grafting, the operative time was 225 (112 to 475) minutes, even including fellow training. It is feasible to teach TECAB with adequate safety if the trainee performs distinct portions of the complex procedure (eg, port placement, IMA takedown, pericardial lipectomy, pericardiotomy, suturing of the anastomosis). With increased experience and efficiency with each piece, the trainee can eventually put all of the elements of the procedure together to complete an entire operation. Time requirements for the learning curves of the second generation of robotic coronary bypass surgeons to learn TECAB are lower than for the first generation. 37 For the foreseeable future, realistic time requirements for robotic CABG will be in the range of 3 to 5 hours if multivessel CABG is included. With operative times in this range, it is possible to complete 2 procedures in a day in a single operating room. Robotic Coronary Artery Bypass Grafting as Part of Hybrid Coronary Intervention Completely endoscopic placement of a left IMA to the left anterior descending artery or placement of 2 IMA grafts to the left ventricle follows an established long-term therapeutic concept with potentially enhanced survival and is therefore a valuable element of hybrid coronary revascularization procedures. Hybrid coronary interventions combine less invasive surgery and percutaneous intervention as a viable alternative to multivessel percutaneous coronary intervention and multivessel open CABG. Robotic TECAB was combined with percutaneous coronary intervention very early in the conception of hybrid procedures. An international multicenter trial reported the feasibility of robotically assisted TECAB with no mortalities or strokes. 38 In this study, early patency rates of robotically sutured left IMA grafts were encouraging, at 96.3%. Our group performed the first simultaneous robotic hybrid coronary interventions in which both TECAB and percutaneous coronary intervention were performed in a single session. 39 An increasing number of complex and advanced hybrid coronary interventions, including multivessel TECAB and/or multivessel percutaneous coronary intervention, are being reported. 40,41 Current Indications and Contraindications for Totally Endoscopic Coronary Artery Bypass Grafting As multivessel TECAB and advanced hybrid coronary interventions have become feasible, any patient with a clinical indication for CABG can be evaluated for a robotically assisted minimally invasive approach. A multidisciplinary team of cardiologists and heart surgeons should ideally discuss indications on a case-by-case basis. Table 6 lists indications from a coronary anatomic and pathological perspective. Contraindications to TECAB are listed in Table 7. Patients with hemodynamic instability are currently unsuited for robotic approaches. Patients with significant pulmonary disease will not tolerate prolonged periods of single-lung ventilation. Endothoracic scarring after previous thoracic surgery, radiation, trauma, or inflammatory disease can be managed with experience but should be carefully evaluated in the patient s preoperative history. Space limitations and distorted thoracic anatomy must be

6 Bonatti et al Robotic TECAB 241 Table 6. Indications for Totally Endoscopic Coronary Artery Bypass From a Coronary Anatomic Perspective Single bypass grafts LIMA to LAD RIMA to RCA Double bypass grafts LIMA to LAD/diagonal branch sequential graft RIMA to LAD combined with LIMA to circumflex coronary system Triple bypass grafts RIMA to LAD combined with LIMA sequential grafts to the obtuse marginal branches associated with significant lesions of non-lad targets amenable to PCI in hybrid coronary interventions Significant ostial lesions of the RCA Significant LAD/diagonal branch bifurcation lesions Significant LAD/diagonal branch bifurcation lesions associated with significant lesions of non-lad targets amenable to PCI in hybrid coronary interventions Significant lesions of the left main coronary artery or left main equivalents and the circumflex coronary artery system Significant lesions of the left main coronary artery or left main equivalents lesions associated with significant lesions of the RCA system amenable to PCI in hybrid coronary interventions and the circumflex coronary artery system associated with significant lesions of the RCA system amenable to PCI in hybrid coronary interventions Significant lesions of the left main coronary artery or left main equivalents and the circumflex coronary artery system Significant lesions of the left main coronary artery or left main equivalents lesions associated with significant lesions of the RCA system amenable to PCI in hybrid coronary interventions and the circumflex coronary artery system associated with significant lesions of the RCA system amenable to PCI in hybrid coronary interventions LIMA indicates left internal mammary artery; LAD, left anterior descending artery; PCI, percutaneous coronary intervention; RCA, right coronary artery; and RIMA, right internal mammary artery. taken into consideration as well as target vessel quality and the grade of systemic atherosclerosis. Effects of Reduced Surgical Trauma All versions of robotically assisted CABG can lead to a dramatically foreshortened recovery period compared with Table 7. Contraindications for Robotically Assisted Coronary Artery Bypass Grafting Absolute Cardiogenic shock Hemodynamic instability Severely impaired lung function Relative Pleural adhesions after previous thoracic surgery, trauma, radiation, inflammatory disease Significant space limitations (morbid obesity, significantly enlarged hearts) Chest deformities Intramyocardial, heavily calcified, and very small target vessels in beating heart approaches Ascending aortic diameter 35 mm and significant aortoiliac atherosclerosis in on-pump arrested heart approaches sternotomy-based CABG. Derose et al, 12 in their series on robotically assisted CABG through minithoracotomy, report that 82% of patients returned to normal activities within 10 days postoperatively. Kon and colleagues 16 reported a time of 1.8 months for return to all activities for patients undergoing robotically assisted CABG through minithoracotomy. For patients after sternotomy off-pump CABG, this time was 4.4 months. Bonaros et al 42 compared Short Form-36 scores for patients after AHTECAB versus patients after conversion to sternotomy and primary sternotomy. At 1 month postoperatively, scores for general health were higher after TECAB. At 3 months, scores for physical function, role of physical function, and bodily pain were significantly better in the patients who had undergone TECAB. In the same study, patients after TECAB resumed outdoor hiking or biking activities within 1 month postoperatively, whereas these activities were resumed 2 months after sternotomy. Intermediate and Long-Term Results Few articles provide intermediate- and long-term follow-up data. In their 2007 multicenter study on early TECAB experience, de Canniere et al 25 report 91.2% freedom from major adverse cardiac and cerebral events at 6 months in AHTECAB patients and 94.9% in BHTECAB patients. In a follow-up study of the Dresden experience, freedom from major adverse cardiac and cerebral events for the first 41 patients at 5 years was 75.6%. 43 We found a similar rate of major adverse events in our first 25 single-vessel AHTECAB patients, 26 but in this Innsbruck Medical University experience, we also noted a dramatic improvement of freedom from major adverse cardiac and cerebral events for the second, third, and fourth cohorts of 25 patients. Combined Experience: University of Maryland School of Medicine and Innsbruck Medical University The first author of the present review developed TECAB procedures at Innsbruck Medical University in Austria in 2001 and subsequently implemented a robotic CABG program at the University of Maryland in Between October 2001 and October 2010, 498 robotically assisted

7 242 Circulation July 12, 2011 Table 8. Combined University of Maryland and Innsbruck Medical University Totally Endoscopic Coronary Artery Bypass Grafting: Experience From October 2001 to October 2010 (n 410) n (Range) % Age, y 60 (35 90) Male Female EuroSCORE 2 (0 11) Single-vessel TECAB Double-vessel TECAB Triple-vessel TECAB Arrested heart TECAB Beating heart TECAB TECAB duration, min 294 ( ) Hybrid coronary interventions (intention to treat) Conversion to larger thoracic incision 58/ Mortality 3/ Revision for bleeding 29/ IABP postoperatively 7/ Stroke 7/ CVVH 6/ Deep thoracic wound infection 2/ Hospital stay postoperatively, d 6 (2 54) TECAB indicates totally endoscopic coronary artery bypass; IABP, intra-aortic balloon pump; and CVVH, continuous veno-venous hemofiltration. CABG procedures were performed at the 2 institutions. A total of 410 TECAB procedures were performed. The standard EuroSCORE-predicted perioperative mortality was 2%, but the observed mortality was only 0.7%, yielding an observed/expected mortality ratio of Demographic data and postoperative results of the combined series are shown in Table 8. Of note are a low stroke rate and a low rate of renal failure requiring renal replacement therapy. The conversion rate to an open procedure (14.2%) is below the cumulative rate in the literature. Surgical revision for bleeding was higher than in standard open CABG and mainly due to port-hole bleeding during the early phase of our experience. Long-term follow-up results are shown in Figures 2 through 4. Survival, freedom from major adverse cardiac and cerebral events, and freedom from angina appear to meet the standards of conventional CABG in larger prospective randomized trials. 44,45 Summary and Future Aspects In 2010, robotically assisted CABG is reproducible and seems to meet general safety standards in coronary surgery. This is true for both beating and arrested heart robotic operations, including procedures that apply remote access cardiopulmonary bypass and cardioplegia. Minithoracotomy and totally endoscopic port-only approaches reduce surgical trauma while providing cosmetic benefits and preservation of structural thoracic integrity. Many studies show an encouraging reduction of the early postoperative recovery period and a rapid return to full activity. These times are shorter than the usual 3 months of sternal precautions after standard Figure 2. Cumulative survival of 410 patients undergoing totally endoscopic coronary artery bypass grafting from 2001 to 2010 at the University of Maryland and at Innsbruck Medical University. CABG or sternotomy off-pump CABG. The current cost of these benefits is increased operative time. After a learning curve, 1-year freedom from major adverse cardiac and cerebral events after TECAB is 90%. Given the ongoing development in hardware, software, and surgical techniques, robotically assisted CABG is here to stay, and broader application is most likely. Significant surgeon and team learning curves will limit these procedures to dedicated centers and highly specialized cardiac surgeons. Simulation will play a major role in surgeon and team training. More complex procedures will be performed, and we anticipate that a majority of operations that are currently performed through a midline sternotomy will be offered in a minimally invasive robotic surgical fashion over the next 10 years. Hybrid approaches will remain an integral part of robotically assisted CABG. Special developments include procedure-specific robotic instrumentation to optimize expo- Figure 3. Cumulative freedom from angina in 410 patients undergoing totally endoscopic coronary artery bypass grafting from 2001 to 2010 at the University of Maryland and Innsbruck Medical University.

8 Bonatti et al Robotic TECAB 243 Figure 4. Cumulative freedom from major adverse cardiac and cerebral events (MACCE) in 410 patients undergoing totally endoscopic coronary artery bypass grafting from 2001 to 2010 at the University of Maryland and Innsbruck Medical University. sure of the back wall of the heart. Following a general trend in endoscopic surgery, single-port platforms are under development that will enable completion of the entire operation with a single access port. Automatic anastomotic connectors are under development and have undergone early clinical use. If long-term graft patency is acceptable, automatic anastomotic connectors may become an essential component of TECAB and support the broader implementation of robotic procedures. Long-range telesurgical approaches may become feasible, but the ultimate range will remain limited by the latency period of signal transmission. Current technical research projects include virtual immobilization of the target vessel in BHTECAB. The question of whether a completely robotic programmed and automated endoscopic CABG procedure can ever be established will be answered by future generations of medical engineers and cardiac surgeons. In 2010, robotically assisted single- and double-vessel TECAB is reproducible at specialized centers and results in the patient s faster return to a full range of activities. General clinical outcome seems to meet results after standard CABG. For the future, robotics is guaranteed to offer exciting prospects for the surgical treatment of coronary artery disease. None. Disclosures References 1. Stevens J, Burdon T, Siegel L, Peters W, Pompili M, St Goar F, Berry GJ, Ribakove GH, Vierra MA, Mitchell RS, Toomasian JM, Reitz BA. Port-access coronary artery bypass with cardioplegic arrest: acute and chronic canine studies. Ann Thorac Surg. 1996;62: Loulmet D, Carpentier A, d Attellis N, Berrebi A, Cardon C, Ponzio O, Aupecle B, Relland JY. Endoscopic coronary artery bypass grafting with the aid of robotic assisted instruments. J Thorac Cardiovasc Surg. 1999; 118: Lehr EJ, Grigore A, Reicher B, Zimrin D, Bartlett S, Griffith BP, Bonatti J. Dual console robotic system to teach beating heart total endoscopic coronary artery bypass grafting: a video presentation. Interact Cardiovasc Thorac Surg. 2010;8:S113 S Argenziano M, Katz M, Bonatti J, Srivastava S, Murphy D, Poirier R, Loulmet D, Siwek L, Kreaden U, Ligon D. Results of the prospective multicenter trial of robotically assisted totally endoscopic coronary artery bypass grafting. Ann Thorac Surg. 2006;81: Bonatti J, Schachner T, Bernecker O, Chevtchik O, Bonaros N, Ott H, Friedrich G, Weidinger F, Laufer G. Robotic totally endoscopic coronary artery bypass: program development and learning curve issues. J Thorac Cardiovasc Surg. 2004;127: Falk V, Diegeler A, Walther T, Banusch J, Brucerius J, Raumans J, Autschbach R, Mohr FW. Total endoscopic computer enhanced coronary artery bypass grafting. Eur J Cardiothorac Surg. 2000;17: Dogan S, Aybek T, Andressen E, Byhahn C, Mierdl S, Westphal K, Matheis G, Moritz A, Wimmer-Greinecker G. Totally endoscopic coronary artery bypass grafting on cardiopulmonary bypass with robotically enhanced telemanipulation: report of forty-five cases. J Thorac Cardiovasc Surg. 2002;123: Bonatti J, Schachner T, Bonaros N, Ohlinger A, Danzmayr M, Jonetzko P, Friedrich G, Kolbitsch C, Mair P, Laufer G. Technical challenges in totally endoscopic robotic coronary artery bypass grafting. J Thorac Cardiovasc Surg. 2006;131: Reuthebuch O, Comber M, Grünenfelder J, Zünd G, Turina M. Experiences in robotically enhanced IMA-preparation as initial step towards totally endoscopic coronary artery bypass grafting. 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10 Robotically Assisted Totally Endoscopic Coronary Bypass Surgery Johannes Bonatti, Thomas Schachner, Nikolaos Bonaros, Eric J. Lehr, David Zimrin and Bartley Griffith Circulation. 2011;124: doi: /CIRCULATIONAHA Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX Copyright 2011 American Heart Association, Inc. All rights reserved. Print ISSN: Online ISSN: The online version of this article, along with updated information and services, is located on the World Wide Web at: Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at: Subscriptions: Information about subscribing to Circulation is online at: