Hybrid Robotic-Assisted Coronary Revascularization and Transcatheter Aortic Valve Replacement: A Single-Center Experience

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Objectives. The efficacy of hybrid robotic-assisted coronary artery bypass grafting (CABG) and transcatheter aortic valve replacement (TAVR) for coronary and aortic valve disease is poorly reported. Herein, we report our experience with this hybrid approach.

Methods. Between January 2018 and June 2022, 10 (7 male, 3 female) patients with a mean age of 81 years underwent the hybrid procedure. Coronary revascularization was performed prior to TAVR with robotic-assisted left internal mammary artery-to-left anterior descending (LAD) bypass grafting for left main or proximal LAD lesions with or without multivessel disease with or without hybrid percutaneous coronary intervention (PCI).

Results. Five patients had left main disease, and 5 had proximal LAD disease with or without multivessel disease. All patients tolerated the robotic-assisted CABG procedure well; 9 patients were extubated in the operating room and all patients were ambulatory on postoperative day 1. Five patients underwent hybrid PCI for non-LAD lesions. TAVR was subsequently performed at intervals ranging from 3 days to 5 months after CABG. One patient with end-stage renal disease on hemodialysis required hospitalization for heart failure during the interval period. The 1-year mortality rate was 0%, and 3 patients died during late follow-up (24-43 months).

Conclusions. This innovative, less invasive approach demonstrates the potential for early recovery in appropriately selected patients with complex coronary and aortic valve disease with promising mid-term outcomes.

Transcatheter aortic valve replacement (TAVR) has been used to treat patients with symptomatic severe aortic stenosis (AS)¹ and failed bioprostheses.² In addition, TAVR combined with percutaneous coronary intervention (PCI) is considered a minimally invasive alternative for aortic valve disease and coronary artery disease (CAD).³ However, the optimal strategies for AS and CAD remain controversial. A subanalysis of the randomized SURTAVI (Safety and Efficiency Study of the Medtronic CoreValve System in the Treatment of Severe, Symptomatic Aortic Stanosis in Intermediate Risk Subjectives Who Need Aortic Valve Replacement) trial reported comparable outcomes between TAVR/PCI and surgical aortic valve replacement (SAVR)/coronary artery bypass grafting (CABG) in intermediate-risk patients with severe AS and non-complex CAD (Synergy Between PCI with Taxus and Cardiac Surgery Trial [SYNTAX] score ≤ 22).⁴ In addition, some lesions are not amenable to PCI, such as left main coronary artery (LMCA) disease with high anatomic complexity.³ Under these circumstances, full sternotomy SAVR and CABG have traditionally been required. These findings underscore the complexity of the decision-making process in treatment strategies for AS and CAD and highlight the importance of individualized treatment plans.

Robotic-assisted CABG has recently been shown to be a minimally invasive revascularization strategy with clinical outcomes comparable to traditional CABG, offering patients coronary revascularization without sternotomy and with early recovery.⁵ However, there is a paucity of literature on the hybrid approach combining robotic-assisted CABG and TAVR. This study aims to fill this gap by detailing outcomes of patients undergoing this novel approach for the treatment of both coronary artery and aortic valve disease.

This study was approved by our institutional human research committee, and written informed consent was obtained from each patient for publication of this study.

Between January 2018 and June 2022, 834 and 1030 patients underwent robotic-assisted CABG and TAVR, respectively, at our institution. Of these, 10 patients underwent hybrid robotic-assisted CABG and TAVR. The principle of this hybrid approach is to avoid both sternotomy and the use of cardiopulmonary bypass by performing a small left thoracotomy and off-pump anastomosis of the left internal mammary artery (LIMA) to the left anterior descending (LAD) artery, followed by TAVR. The decision for the hybrid approach was made by a dedicated heart team, primarily based on age and surgical risk according to the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM), as well as patient anatomy and patient-specific factors such as frailty. If intervention was indicated for severe AS/failed aortic bioprosthesis, screening for CAD was performed by contrast-enhanced coronary computed tomography angiography or invasive coronary angiography. Coronary revascularization was then considered based on both angiographic and physiological evidence. More specifically, for angiographically intermediate stenosis lesions, an instantaneous wave-free ratio (iFR) less than 0.89 was used to guide the decision to proceed with revascularization.

For coronary revascularization combined with TAVR, the Heart Team carefully considered the risks and benefits of both robotic-assisted CABG and PCI for LMCA and/or proximal LAD artery disease. While some lesions may be treatable with PCI, the evaluation of the suitability of each method was based on factors such as anatomical complexity, including bifurcation lesions, lesion length, presence of chronic total occlusion, severe calcification, and/or combined multivessel disease to determine the most appropriate approach on a case-by-case basis. Details of robotic-assisted CABG procedures have been previously reported.⁶ Briefly, robotic-assisted CABG was performed under general anesthesia with robotic harvesting of the LIMA in a skeletonized fashion, followed by off-pump direct anastomosis to the LAD with a small anterior thoracotomy (3-4 cm) at the site of the initial camera port. If other grafts, such as the radial artery, are used, 1 side of the graft is anastomosed to the LIMA in a Y- or T-shaped anastomosis and the other side to the coronary targets, such as diagonal and intermediate branches, in either a sequential or end-to-end fashion. In multivessel disease, hybrid PCI was considered for proximal non-LAD lesions deemed angiographically or physiologically significant before or after robotic-assisted CABG. In general, coronary revascularization was performed prior to TAVR, and the interval between coronary revascularization and TAVR was determined based on symptoms and severity of coronary and aortic valve disease. Some patients underwent balloon aortic valvuloplasty as a bridge therapy prior to CABG. This was intended to temporarily improve aortic valve function and contribute to improved safety and hemodynamic stability during the CABG procedure.

The Sapien (Edwards Lifesciences) and Evolut (Medtronic) valves were used during the study period. The choice of the valve (balloon-expandable or self-expanding valve) was based on individual patient factors, such as the anatomy of the aortic root complex and access routes, as well as the discretion of the interventionist. It is important to note that although all patients in this study had concomitant CAD, which is a potentially important factor in valve selection favoring balloon-expandable Sapien valves, the choice of the self-expanding Evolut valves is not precluded due to improved implantation techniques, such as the commissural alignment technique,⁷ the low incidence of unplanned PCI, and the feasibility of PCI after TAVR with self-expanding Evolut valves.⁸

Baseline characteristics of the 10 patients are summarized in Table 1. Eight patients were octogenarians, and the other 2 patients were selected for the hybrid procedure due to their intermediate to high surgical risks. Five patients had LMCA disease, including 3 with multivessel disease. In addition, 5 patients had proximal LAD disease, 2 of whom had multivessel disease. The SYNTAX scores ranged from 13 to 35.5, and 5 patients had a SYNTAX score greater than 22 (Table 2). The Figure shows the coronary angiography of a patient with LMCA bifurcation and LAD disease (case 7). Table 2 summarizes coronary revascularization characteristics of the patients.

All patients underwent LIMA to LAD bypass grafting, with 1 patient receiving a radial artery to diagonal branch bypass. All patients but 1 were extubated in the operating room after CABG, and all patients tolerated ambulation and oral feeding on postoperative day 1. No patient required blood products intraoperatively. One patient with end-stage renal disease (case 8) experienced postoperative gastrointestinal bleeding requiring blood transfusion and gastrointestinal endoscopy. Five patients underwent hybrid PCI for non-LAD lesions, 4 of whom received PCI during the same admission for CABG. Additionally, 2 patients with very severe AS (cases 7 and 9) underwent balloon aortic valvuloplasty prior to CABG surgery.

The median hospital length of stay after CABG was 5 days, including 2 patients who underwent TAVR during the same admission for CABG. The interval between CABG and TAVR ranged from 3 days to 5 months. During the interval, 1 patient (case 8) required hospitalization for acute heart failure — which was stabilized with medical management, including hemodialysis — and underwent elective TAVR. TAVR characteristics are summarized in Table 3. In this cohort, all patients underwent transfemoral TAVR under conscious sedation, with 1 patient receiving a valve-in-valve procedure for prosthetic aortic valve stenosis (case 7). This patient required a second valve due to the malposition of the first transcatheter valve. The Sapien 3 valve was used in 5 patients, and the Evolut Pro/Pro+ valve was also used in another 5 patients. Seven patients were discharged home on post-procedural day 1, and the remaining patients who experienced conduction disturbances and required permanent pacemaker implantation after TAVR were discharged on post-procedural days 2 and 3. All patients improved to New York Heart Association class I/II heart failure symptoms at 1-month follow-up. During follow-up, 1 patient with end-stage renal disease (case 8) died suddenly 43 months after TAVR, and 2 patients died of non-cardiovascular causes (24 and 34 months, respectively). All patients survived at least 15 months after TAVR, and none required additional coronary revascularization.

This study, with the largest cohort of hybrid robotic-assisted CABG and TAVR to date, demonstrated that the hybrid of robotic-assisted coronary revascularization and TAVR is feasible, less invasive, and has the potential for early recovery in appropriately selected patients with complex coronary and aortic valve disease, with promising mid-term outcomes.

The 2020 American College of Cardiology/American Heart Association guidelines3 suggest that, in patients undergoing TAVR with significant left main or proximal CAD, revascularization with PCI prior to TAVR is reasonable (Class 2a). The guidelines also state that, in patients with significant AS and significant complex bifurcation LMCA disease and/or multivessel disease with a high SYNTAX score, SAVR and CABG are preferable to TAVR and PCI (Class 2a). In addition, concomitant CABG is recommended in patients undergoing SAVR with significant proximal CAD (Class 2a). Each of these approaches has its advantages and drawbacks. TAVR and PCI are minimally invasive procedures, but usually require dual antiplatelet therapy, and some lesions are anatomically unsuitable for PCI.

In contrast, SAVR and CABG are more invasive and usually require sternotomy and cardiopulmonary bypass, resulting in longer recovery times for patients. Robotic-assisted CABG and TAVR offer a less invasive alternative to conventional CABG and SAVR or minimally invasive AVR and PCI by avoiding sternotomy and/or the use of cardiopulmonary bypass while providing LIMA to LAD revascularization. In addition, this approach facilitates early postoperative mobilization and oral feeding, as described in the present study, which is particularly beneficial for elderly and frail patients. Although large, randomized trials comparing robotic-assisted CABG to traditional CABG are still lacking, a number of observational studies have suggested that robotic-assisted CABG is as safe and effective as traditional CABG.^5,9

Given the less invasive nature of the robotic-assisted CABG and the potential benefit of LIMA-to-LAD bypass over PCI, we sometimes perform robotic LIMA-to-LAD bypass for isolated proximal LAD lesions, depending on patient status and lesion anatomy. The benefits of robotic-assisted LIMA-to-LAD bypass and TAVR over PCI and TAVR or conventional CABG and SAVR for significant AS with proximal LAD lesion need to be further investigated. Another potential advantage of LIMA-to-LAD bypass over PCI is the avoidance of dual antiplatelet therapy. While optimal antithrombotic therapy after TAVR remains controversial, the 2020 American College of Cardiology/American Heart Association guidelines recommend single antiplatelet therapy with aspirin for patients undergoing TAVR in the absence of other indications for oral anticoagulants.³ Therefore, we believe that robotic-assisted CABG without hybrid PCI and TAVR with single antiplatelet therapy is also a reasonable option for patients at high risk of bleeding.

Potential disadvantages of robotic-assisted CABG prior to TAVR include the risk of hemodynamic instability during the CABG procedure due to severe AS. Despite these concerns, previous studies have demonstrated favorable outcomes of traditional off-pump CABG followed by TAVR.¹⁰ Our study also suggests the feasibility and safety of this hybrid approach. This success may be due in part to increased experience and improved understanding of anesthetic management of severe AS. In addition, robotic CABG is potentially more beneficial than traditional off-pump CABG in terms of reduced blood loss by avoiding sternotomy.^5,6 However, caution must be exercised both during the CABG procedure and in the postoperative period. In fact, 1 hemodialysis patient suffered acute heart failure requiring hospitalization during the interval between CABG and TAVR. Careful fluid volume control and determination of the optimal timing of both interventions are essential to ensure patient safety. Another potential disadvantage is that the initial costs of robotic-assisted CABG and TAVR may be higher than those of SAVR and CABG. However, these higher costs may be offset by shorter intensive care unit/hospital stays, fewer complications, and less need for blood products in the robotic-assisted CABG and TAVR.⁶

This single-center retrospective study with only 10 cases has significant limitations. Its singular institutional focus may introduce bias resulting from the center's unique patient demographics or clinical practices, thereby limiting the broader applicability of its findings. The study is also susceptible to selection bias, exemplified by choices such as SAVR vs TAVR or CABG vs PCI, suggesting that the sample may not accurately represent the broader population. In addition, uncertainty about long-term outcomes compounds these problems. Taken together, these limitations pose significant challenges to the robustness of the study and the validity of its conclusions. In particular, this single-arm study does not provide comparative insights about the effectiveness of this approach over traditional TAVR/PCI or SAVR/CABG. Despite these limitations, it is noteworthy that, to the best of our knowledge, this represents the largest cohort studied focusing on robotic-assisted CABG and TAVR.¹¹ Based on our findings, we believe that this hybrid procedure is a viable treatment option. To better understand the role of hybrid robotic-assisted CABG and TAVR in the treatment of complex coronary and aortic valve disease, comparative studies with larger cohorts are needed to provide deeper insights and more reliable data.

From the ¹Department of Cardiothoracic Surgery Research, Lankenau Institute for Medical Research, Wynnewood, Pennsylvania, USA; ²Department of Cardiothoracic Surgery, Lankenau Heart Institute, Wynnewood, Pennsylvania, USA; ³Department of Interventional Cardiology, Lankenau Heart Institute, Wynnewood, Pennsylvania, USA.

Disclosures: Dr Ramlawi is a consultant for Medtronic, Boston Scientific, AtriCure, and Corcym. The remaining authors report no financial relationships or conflicts of interest regarding the content herein.

Address for correspondence: Yoshiyuki Yamashita, MD, PhD, Department of Cardiothoracic Surgery Research, Lankenau Institute for Medical Research, 100E Lancaster Ave, Wynnewood, PA 19096, USA. Email: YamashitaY@mlhs.org

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