Robotic Totally Endoscopic Beating-Heart Unroofing of a Left Anterior Descending Artery Myocardial Bridge

In this new CTSNet President’s Series, Dr. Husam Balkhy, president of ISMICS, showcases cutting-edge, totally endoscopic cardiac procedures from the University of Chicago. Watch for more videos in this series coming soon. 

Introduction 

A 46-year-old male with chest pain was diagnosed with a myocardial bridge of his proximal/mid left anterior descending artery. He was recommended surgical unroofing via sternotomy but came to the author’s institution seeking a sternal-sparing option. All imaging and work-up were reviewed, and he was deemed a suitable candidate for robotic-assisted unroofing of his LAD-MB.  

Surgical Techniques 

The surgeons performed MB unroofing off-pump using the DaVinci Si robot with the EndoWrist stabilizer. A left bronchial blocker was used for left lung isolation. The patient was placed in the supine position with a left shoulder bump. Ports were placed in the left second, fourth, and sixth intercostal spaces (ICS). A 12 mm subcostal port was placed for the fourth robotic arm and the EndoWrist stabilizer, along with a second anterior ICS 8 mm AirSeal working port. A posterior pericardiotomy was made, and the anterior pericardium was opened along the length of the LAD. The LAD was identified where it is an epicardial vessel (usually toward the distal third) and the stabilizer was positioned. The LAD was followed proximally, carefully dividing the myocardial bridging fibers using bipolar electrocautery (initially used to avoid ventricular arrhythmias with low settings of 10W, increasing as needed to control bleeding from epicardial veins). After the bridging muscle was rendered electrically inactive, the surgeons switched to monopolar electrocautery or Potts scissors if needed to divide the muscle. This continued proximally along the LAD until the anterior arterial wall was fully exposed. It is important to fully visualize and stay on the LAD anterior wall during the dissection to avoid moving off it and inadvertently entering the right ventricle (RV). Care was taken to identify small epicardial coronary veins, which may have run near or crossed over the LAD. When encountered, meticulous hemostasis was achieved using bipolar electrocautery or metal clips. Given that the procedure was performed off-pump, systemic heparin was avoided, which helped with hemostasis. The robotic EndoWrist stabilizer, controlled by the console surgeon, was vital to the procedure, and its position was adjusted continuously to maintain adequate exposure of the LAD deep in the myocardium. 

Conclusion 

Robotic beating-heart complete unroofing was successfully performed, aided by the enhanced visualization provided by the robotic approach. The patient had an unremarkable postoperative course, was discharged from the hospital in two days, and, at the last follow-up, reported significant symptom improvement without the use of any anti-anginal medications. 

Comments 

The authors believe that the robotic-endoscopic off-pump approach for MB unroofing is beneficial because patients experienced known benefits, including short LOS, less blood transfusions, no sternal wound infections, and swift recovery. 
Additionally, a significant benefit of the robotic-endoscopic approach is enhanced visualization. In the author’s experience, this—coupled with an off-pump/no heparin strategy—decreases the incidence of complications. One of the primary concerns in MB unroofing is RV perforation, which is why most procedures are performed on-pump/arrest-heart. The authors believe that the course of the intramyocardial LAD, MB muscle fibers, and bridging veins are highly visible in a robotic approach. In this series, there were no RV perforations. Additionally, an advantage of the totally endoscopic approach over mini thoracotomy is achieving greater completeness of the myotomy, as longer or multiple LAD segments (or large diagonal branches) can be visualized along the entire course and fully unroofed. 

The importance of the robotic epicardial stabilizer in any robotic-assisted off-pump surgery cannot be overstated. It is fully controlled by the surgeon at the console. It spreads gradually and smoothly, allowing for frequent adjustments to achieve perfect exposure, and can spread the deep epicardial fat to expose the overlying muscle fibers, rendering a deep target more superficial without the need for additional retraction. 

References

1. Nisivaco S, Kitahara H, Balkhy HH. Robotic totally endoscopic beating-heart unroofing of a left anterior descending artery myocardial bridge. Ann Cardiothorac Surg. 2024;13(4):385-387. doi:10.21037/acs-2023-rcabg-0193
2. Nisivaco S, Blair J, Patel A, et al. Robotic Totally Endoscopic Off-Pump Unroofing of Myocardial Bridge: Early Experience and Midterm Outcomes. Innovations (Phila). 2024;19(4):409-415. doi:10.1177/15569845241266817

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