Author + information
- Robert C Ashton Jr, MD and
- Jonathan S Steinberg, MD
In “rolling their eyes” in response to our recent report on robotic biventricular pacing, Drs. Lick and Saeed failed to “see” the potential impact of an endoscopic, site-directed approach. Based on their limited experience (four patients) of left ventricular (LV) lead placement through a small anterior thoracotomy, they have concluded that this approach is superior to robotic, endoscopic lead placement. Unfortunately, follow-up echocardiographic and clinical data are unavailable on these patients, and supporting data for this approach are lacking in the contemporary international literature.
We have performed over 100 limited anterior and antero-lateral thoracotomies for both minimally invasive mitral valve repair and robotically assisted minimally invasive coronary artery bypass graft (CABG). These incisions have propelled forward the field of minimally invasive cardiac surgery, and we continue to work toward totally endoscopic treatments for complex cardiac disease. However, it was our vast experience with these incisions that made us conclude that this was exactly the wrongapproach for the intricacies of biventricular pacing. In our experience with both single- and multi-vessel robotically assisted minimally invasive CABG through a limited (6 cm) antero-lateral thoracotomy, we have found that even with endoscopic stabilization in normal-sizedhearts, the most lateral access to the LV is the region of a ramus intermedius or high obtuse marginal vessel. In the massively enlarged hearts that we have encountered in our robotic biventricular pacing experience (mean left ventricular end-diastolic diameter, 6.9 cm), the obtuse marginal (OM) vessels are displaced even further laterally into the left chest. In these cases, limited anterior thoracotomy results in a “keyhole” view of, at best, the region of the first diagonal and mostly the region of the left anterior descending coronary artery (LAD). If Drs. Lick and Saeed were able to access the true lateral wall (region between OM1 and OM2) with this incision, then they have accomplished something in four cases that minimally invasive CABG surgeons have been trying to do in normal hearts for the past five years. Limited lateral and postero-lateral thoracotomy with the patient in the full decubitus position has been described for OM access, but this is not the procedure that the authors are referring to.
As electrophysiologists have known for years, LV stimulation site is critical to the success of cardiac resynchronization therapy (CRT). In both short- and long-term studies, it is clear that coronary sinus leads in the postero-lateral distribution provide better hemodynamic results than lateral sites, which provide still better augmentation than anterior sites (1,2). The obvious advantage to the robotic, totally endoscopic approach is the ability to access the entireLV. This access allows both electrophysiologic and echocardiographic mapping of the LV in order to delineate the best LV site for CRT. It is our hope that we will be able to improve upon the 33% “non-responder” rate to CRT with such an approach.
Finally, Drs. Lick and Saeed imply that robotic CRT with single-lung ventilation and chest insufflation is a physiologically taxing procedure for these frail patients. In most cases we perform lead placement without chest insufflation. However, a pilot study at our institution analyzing the hemodynamic and subtle echocardiographic effects of chest insufflation in patients undergoing robotic cardiac surgery revealed nohemodynamic consequences in the biventricular pacing population. In fact, it was these very patients with high intracardiac pressures and large cardiac/pulmonary ratios who were most resistant to insufflation (Belsley et al., unpublished data, June 2003).
As with any new technology, robotic surgery does require the seamless coordination of the surgical, nursing, and anesthesia teams. At our institution, we have performed 65 robotic cases over an 18-month period, and this seamless process occurs without delays in our operating room. The skin-to-skin robotic times for our last 15 cases averaged 45 min, and these times are accurately recorded as part of a number of ongoing trials. Drs. Lick and Saeed report an operative time of “8 to 10 minutes” for their procedure. It is unclear whether this “time” actually includes incision, lead placement, lead tesing, tunneling, device connection, and skin closure.
The optimal CRT implantation procedure may not yet have been identified, but it is hoped that continued scientific investigation will improve the way we treat patients with refractory heart failure. We must continue to keep our “eyes” focused on the past while maintaining a vision for the future.
- American College of Cardiology Foundation
- Butter C.,
- Auricchio A.,
- Stellbrink C.,
- et al.