The role of robotic totally endoscopic coronary artery bypass in the future of coronary artery revascularization

On 1 September 2013, Stephan Elop, the former CEO of Nokia, announced the acquisition of Nokia by Microsoft in a deal valued at 7.17 billion USD. At that time Mr Elop ended his speech with the following words: ‘We didn’t do anything wrong but somehow we lost’ [1]. Such an ending is devastating considering that just 3 years earlier, in 2010, Nokia was the 5th most valuable brand in the world, holding 40% of the market share of cell phones. It was the first brand in the mobile industry and had a total net worth of 13 billion USD, 4% of Finland’s Gross Domestic Product at that time [2]. The events that lead to such a dramatic end have been examined carefully by several analysts [1] and most of them agree that Nokia did nothing wrong. It was their refusal to change and learn new things, and their lack of innovation that ultimately lead to their demise. There are many lessons for the current generation of cardiothoracic surgeons; particularly those interested in surgical revascularization can learn from Nokia’s story. In the last 20 years, more than a dozen randomized controlled trials have compared coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in what can be seen as an eternal scientific debate [3]. The summary of this debate has been consistent throughout all these trials: In stable coronary artery disease (CAD), CABG has consistently shown improved survival and reduction in new myocardial infarctions, particularly in the presence of multivessel CAD or diabetes mellitus. In stable CAD, PCI, independent of the generation of stent used, has thus far failed to report an improvement in survival or a significant reduction in new myocardial infarction. The reason behind the superiority of CABG over PCI in treating stable CAD has been elegantly presented in a recent review from JACC [4]. While both PCI and CABG treat a flow-limiting lesion, CABG offers a second adjunct myocardial protection mechanism by landing in the distal two-thirds of a coronary artery, thereby stabilizing those plaques that may not be flow-limiting at the time of the coronary revascularization but are at high risk of rupturing or causing vessel occlusion in the future. The ‘surgical collateralization effect’ of CABG over PCI is independent of any stent generation and it assumes a crucial role, particularly in diabetic patients. The 7-year results of the Freedom trial confirmed this finding, acknowledging the superiority of CABG over PCI in treating stable coronary disease in diabetic patients, independently of the SYNTAX score [5]. Despite the robust scientific evidence, and the current clinical practice guidelines in support of CABG, in the ‘real-world’ management of stable coronary disease, PCI is the most commonly chosen procedure. Some of the reasons for the increased adoption of multivessel PCI versus CABG include: patient preference, the limited invasiveness of the procedure, lack of a proper informed consent on the long-term consequences of the 2 different revascularization strategies, and sometimes, perhaps, a conflict of interest in that the interventional cardiologist who performs the diagnostic test is the same person performing the PCI procedure [6]. But a crucial responsibility in the limited adoption of surgical revascularization lies with cardiac surgeons. It is hard to justify why surgeons are not promoting innovation and have been slow to adopt new techniques proven to offer a benefit for patients. As per the Society of Thoracic Surgeon database 2017, a second arterial conduit was offered in <10% of CABG and the overall adoption of robotic-assisted coronary surgery accounts for <1% of the entire volume of CABG in USA. In this fraction, both robotically assisted minimally invasive direct CABG [robotic harvest of the left internal thoracic artery (LITA) and mini-thoracotomy to perform the LITA to left anterior descending coronary artery (LAD) anastomosis] and Totally Endoscopic Coronary Artery Bypass Grafting (TECAB) (complete robotic coronary revascularization including both internal thoracic artery harvest and robotically assisted coronary anastomosis) are accounted for [7]. There are several advantages of TECAB in comparison to any other strategy of revascularization: TECAB is performed using 5 ports (8 or 12 mm) in the left chest with no thoracotomy or sternotomy. This allows for a quick recovery with early postoperative discharge from the hospital (2 or 3) and a quick return to daily activity: the absence of any thoracotomy or sternotomy makes the postoperative pain minimal and return to daily activity the quickest among any other minimally invasive coronary bypass surgical approach (Fig. 1). TECAB allows for the harvesting of both thoracic artery conduits with no risk of wound infection, by sparing the sternum. Independently of body mass index, gender or glycated hemoglobin, bilateral thoracic arteries (BITAs) can be chosen as the grafts of choice. By performing TECAB off-pump using BITA inflow, an all-arterial revascularization can be achieved for the left coronary system with a no aortic touch technique, minimizing the risk of stroke while offering the long-term benefits of a multiarterial revascularization. In a closed chest environment, the right internal thoracic artery (RITA) is actually closer to the heart than generally perceived in an open sternotomy case, and can reach left side targets passing underneath the anterior mediastinal fat. A robotic TECAB performed with Intuitive Si system. Four ports are docked to the patient. From left to right: the EndoWrist stabilizer, the left arm, the camera and the right arm. The ‘as-treated’ analysis of the ART trial and several large propensity-matched cohort studies have shown the superiority of multiarterial bypass grafting versus a single ITA and veins strategy in sternotomy CABG [8]. One of the major limitations in adopting this approach has been the fear of sternal wound infections when performing this operation via sternotomy. When the sternum is spared during robotic TECAB, BITA harvesting becomes much more feasible for a larger number of patients. The 2 internal mammary artery grafts can be used in different configurations: the LITA can usually reach the LAD and Diagonal using sequential grafting. The RITA can reach any ramus intermedius and most high obtuse marginal branches of the circumflex artery (OM 1 and 2). If an OM3 is needed, the LITA can be used to serve the lateral wall while the RITA can be anastomosed to the anterior wall. Complex ‘Y’ grafts can also be performed with the RITA branching out from the LITA while serving the entire heart with a single inflow. The right coronary artery is difficult to approach on the beating heart from the usual left-sided ports. While revascularization of the right coronary artery (RCA) can be achieved using the RITA as a dedicated graft (with the robot docked on the right chest), a heart team discussion is mandatory whenever the RCA is involved as part of multivessel disease in order to assess the feasibility of a percutaneous solution for the right coronary artery using a hybrid strategy. If this is not a good option, a sternotomy CABG may serve the patient better in achieving a more satisfactory and complete revascularization. Despite the multitude of advantages of TECAB over any other form of minimally invasive coronary artery revascularization, there is a consistent reluctance from cardiac surgeons to adopt such techniques. We believe that there a few important reasons behind the lack of evolution and adoption of robotic technology in coronary artery bypass surgery over the last 20 years: It is clear that the lack of a dedicated subspecialty in coronary surgery represents a major limitation in advancing innovative techniques in surgical revascularization. Only in the setting of a dedicated team to treat CAD would formal widespread adoption of these techniques be possible. Robotic TECAB requires a steep learning curve not currently supported by the industry: disengagement of the industry in TECAB has become clear as the last generation of Intuitive’s robotic platform (Xi) does not include a coronary stabilizer as a tool offered with the system. The coronary stabilizer has been discontinued with major repercussions to those performing or interested in performing such procedures. We believe that the stabilizer is an extremely valuable and versatile device that facilitates endoscopic surgery on the beating heart, and we have used it not only for TECAB procedures but also in robotic cardiac ablation and totally endoscopic pericardiectomy. Finally, the industry has discontinued production of the only Food and Drug Administration-approved distal coronary anastomotic device, which was available for over 10 years and facilitated our TECAB experience. The absence of this device will make the learning curve of closed chest coronary surgery even more complex for surgeons wishing to perform this procedure (Fig. 2). Endoscopic view of a Flex-A (AesDex, Redwood City, CA, USA) distal anastomotic connector loaded with an internal mammary artery graft, ready for deployment on the left anterior descending artery. The disengagement of the industry from cardiac surgery in recent years and in particular from robotic heart surgery and TECAB is a reflection of the hesitation and reluctance of our specialty to embrace innovation. After being part of the most advanced and technology-driven subspecialty in medicine, cardiac surgeons, in recent years, have mostly avoided innovation and adopted a very conservative style of performing surgery. Minimally invasive cardiac surgery continues to have its proponents, but it also continues to face an uphill battle, with a lot criticism coming from within the specialty. At the same time, there is much enthusiasm towards catheter-based therapies, which are now the focus of the industry, despite the fact that concern still exists for the medium- and long-term outcomes of such percutaneous approaches for treating structural and coronary heart disease. In this complex scenario, the metrics that are used to address quality in cardiac surgery are focused on 30-day mortality, early discharge and immediate results of the procedure, favouring temporary percutaneous solutions above the most definitive surgical treatments that offer a long-term benefits. We believe the time has come to renew surgeons’ interest in Robotic TECAB: The overall volume of CABG surgery has been growing since the early 2000s with >250 000 procedures done in the USA every year and with >95% of them still yet to be performed through a sternotomy. Hybrid coronary revascularization is seeing a growth in interest from both cardiac surgeons and interventional cardiologists: the value of LITA to LAD as well as the value of a second arterial conduit for a left coronary target is well recognized by the interventional cardiology community. Achieving complete revascularization with a hybrid approach particularly when minimally invasive bypass is offered for the left coronary system and stents for the right coronary artery seems to be a reasonable strategy for many patients. The RCA has never been shown to benefit from a second arterial conduit to the same degree of targets on the left coronary system [9]. Moreover, incomplete coronary revascularization achieved with BITA has been proven to be superior to a complete revascularization performed with one ITA and veins [10]. Multiple companies are entering the market to create a new robotic surgical platform. Of the 90K prostatectomies done in 2017 in the USA, 70K have been accomplished using the da Vinci system: if the urological market is somehow saturated by Intuitive, cardiac surgery may represent an area of great opportunity for one of these companies to gain market share in robotic surgery. More technology (including anastomotic devices) is needed to simplify the technique of off-pump TECAB and allow greater adaption of this procedure. We believe that given the steep learning curve to such a technically demanding procedure, it is required that a stepwise approach be available to young surgeons to embrace this operation. Simulators and virtual technology should also be incorporated in any new robotic platform dedicated to cardiac surgery to speed up the learning process in a controlled environment (Fig. 3). Proposed pathway to achieve off-pump TECAB BITA. A solid knowledge in all the most complex techniques of CABG is required. Robotic-assisted MIDCABG with single and bilateral IMAs is the following step. Familiarization in an open setting first and in a closed chest setting with a distal anastomotic device is mandatory. The required steps that are currently limited by industry disengagement are highlighted in purple. BITA: bilateral internal thoracic arteries; CABG: coronary artery bypass grafting; LITA: left internal thoracic artery; MAG: multiarterial grafting; MIDCABG: minimally invasive direct CABG; OPCABG: off-pump CABG; RITA: right internal thoracic artery; TTFM: transit-time flow measurement. The great impact of Tesla on the automotive industry was made possible by the introduction of the less fashionable Toyota Prius in 1999. Despite the fact that Toyota lacked several details and technologies that made Tesla successful many years later, the Prius was a milestone in the automotive market and was the original purchase of many electric car enthusiasts. In the same way, we should revisit the limited adoption of robotics in coronary artery bypass surgery as we witness a resurgence in surgical robotics with many new platforms being introduced. Cardiac surgeons need to increase their involvement in this field so that the industry can engage with us to create the perfect platform that is specifically designed with stabilizers and anastomotic devices to more easily achieve a truly multiarterial off-pump closed chest revascularization. Conflict of interest: Husam H. Balkhy serves as consultant and proctor for Intuitive Surgical. Gianluca Torregrossa does not have any conflict to declare related with the content of the manuscript. Presented at the 33rd Annual Meeting of the European Association for Cardio-Thoracic Surgery, Lisbon, Portugal, 3-5 October 2019.