Keys for Building a Successful Hybrid Program for the Treatment of Persistent and Long-Standing Persistent AF

However, in the sector of catheter-based ablation, these advances mainly improve only the subset of paroxysmal AF; success rates for persistent and longstanding persistent AF remain frustratingly low.^1,2 There is a general notion that successful management of persistent and longstanding persistent AF requires additional elimination of non-pulmonary vein triggers and control of the AF perpetuation substrate. Attempts at maintaining complete isolation of the posterior box or left atrial appendage with catheter ablation has been challenging. With the exception of a few small studies,³ a catheter-based maze procedure is difficult to perform, even for experienced operators. The maze procedure has been successfully performed mainly through a surgical approach. In this article, we discuss our approach to the hybrid procedure, which incorporates minimally invasive epicardial maze via thoracoscopic surgery completed by endocardial catheter mapping and ablation. We also highlight how, with the appropriate dedication and resources, this seemingly complex task (from both its technical component and coordination efforts) can be successfully accomplished, even in a small rural hospital without a dedicated hybrid room.

The Cox-Maze Procedure

The Cox-Maze procedure, as described by its inventor, Dr. James Cox, requires the creation of multiple lines of conduction block within the left and right atrium. One critical requirement is a transmural lesion, which in the original description, was known as the “cut-and-sew” technique. Later, with the advances of effective ablation energy sources, these were accomplished with either a radiofrequency (RF) or cryothermal modality. There have been several iterations of the Cox-Maze model (Figure 1); however, the essential goal is to isolate the pulmonary veins, the posterior wall, and to excise the left atrial appendage.^4,5 

The maze procedure was initially designed for an open-chest, open-heart surgery. Hence, it was suitable only as a concomitant procedure during valve surgery. With the advent of thoracoscopic surgery, these maze lines could be replicated and performed epicardially (Figures 2-8). With this lesser associated morbidity, video-assisted thoracoscopic surgery (VATS) is an acceptable procedure for an AF-only treatment. A thorough treatment would then require assessment of the integrity of these lines by endocardial mapping, which would also allow the creation of the cavotricuspid isthmus (CTI) line for atrial flutter prevention, as well as completion of any mitral line, which is very difficult to complete epicardially.^6,7

The VATS Maze Procedure

The VATS Maze procedure, which is performed epicardially, closely approximates the lines described in the open maze procedure. Technically, the procedure is performed using thoracoscopic ports to deliver the camera, surgical instrument(s), and ablation tools (Figure 2). 

Ablations are then performed on the right and left atria (Figures 3 and 4). In brief, in the right atrium, this involves superior vena cava (SVC) isolation and an SVC-IVC line. Then, in the left atrium, pulmonary vein isolation (PVI) is performed using bipolar clamps applied simultaneously over both the superior and inferior pulmonary veins. Next, roof and floor lines are added, as well as a line connecting the left superior pulmonary vein (LSPV) to the base of the left atrial appendage (LAA) and a mitral isthmus line, typically connecting the left inferior pulmonary vein (LIPV) to the mitral annulus. This line is typically difficult to complete, as the tissue at the annulus turns endocardially. In the majority of cases, an endocardial completion is necessary. In addition to those maze lines, ganglionic plexus (GP) ablations are also performed (Figure 5). Video screen shots are shown in Figures 6-8.

A significant advantage of VATS Maze is LAA clipping. This “bonus” procedure essentially provides a permanent anticoagulation substitute for the patient. LAA clipping is performed using the AtriClip (AtriCure, Inc.). (Figure 8)

The Catheter Stage

Following the VATS Maze, the patient undergoes a catheter-based procedure to assess the integrity of the VATS Maze lesions. In this procedure, any incomplete lines are completed, and the CTI line is added. Typically, PVI lines are robust, and the posterior box is found to be quiet. The mitral line is often incomplete at the annulus, and endocardial ablation lesions are frequently needed. This is accomplished by assessing the gap of the epicardial lesion, which is typically near the mitral annulus. Endocardial ablation can be applied (Figure 9). At times, endocardial ablation alone is insufficient to complete the mitral line, and further ablations are needed from within the coronary sinus. Some patients present with mitral flutter (Figure 10). The CTI line is also routinely added. 

In the rare cases where the roof or floor line is incomplete, endocardial ablation is necessary (Figure 11). These touch-up lesions are easily completed if the line is, presumably, partially present epicardially. The key distinction between “completing” an epicardial line and creating a de novo transmural endocardial line is that the former is much easier to accomplish.

Our Outcomes 

Outcomes for the hybrid procedure at our institution have thus far mimicked our success rates for the open maze procedure. We have treated over 400 patients with this hybrid procedure since 2013. In 2016, we reviewed our preliminary data and found that in the over 250 patients who have completed both stages, 78% remain AF-free and most are off antiarrhythmic drugs after 3 years. Serious complications were rare (two conversions to open-chest surgery, one stroke, and two deaths).⁸ The most gratifying outcome is that QOL has significantly improved for patients. 

Keys for Building a Successful Program

We started this program with two physicians (Dr. Dunnington and Dr. Liem), moving from San Francisco’s competitive South Bay area to the North Bay area. In 2013, we created the program at St. Helena Hospital, a facility of merely 120 beds; we are located in St. Helena, California, near the northern outskirts of wine country. Here we found a very supportive administrative structure, and were soon joined by electrophysiologists Dr. Chang-Sing and Dr. Kaiser. We have built an efficient and competent surgical and EP laboratory staff that incorporates support for complex three-dimensional mapping. Our dedicated nurse navigator, Carrie, has been instrumental in data collection. We have grown from enrolling less than 50 patients a year in 2013 to more than 100 in 2017, achieving the largest hybrid program in the country. 

One would envision that a hybrid program would typically succeed only in major medical centers with hybrid laboratories. Initial progress in hybrid programs took place mainly in university facilities, in a true hybrid room where both the surgical and catheter phases were done in the same setting. In a facility without a hybrid room, such as at our hospital, this “same setting” could be accomplished by transferring the patient, still under general anesthesia, from the operative suite to the electrophysiology laboratory. Under the guidance of experienced operators (both the surgeon and electrophysiologist), the entire procedure can be accomplished in less than 4 hours; thus, a hybrid room is not essential. 

However, in our experience, we found that the two procedures should not be performed on the same day. Unintentionally, we found that when we separated the surgical and catheter stages by 30-45 days, the long-term success was better.⁹ We postulate that, perhaps, delayed confirmation of the integrity of the surgical lines would take into account the tissue recovery from edema. Thus, without the requirement of a hybrid room, a hybrid program can be quite feasible at a hospital of any size. 

One of the keys to our success has been our multidisciplinary group of dedicated physicians and support staff; this small but interactive team has been more efficient than having a large system in place. In fact, our dedicated nurse navigator has been essential to our success. Another critical element is having a cardiothoracic surgeon on staff with extensive experience in VATS procedures, as well as supporting electrophysiologists with knowledge of complex left atrial mapping and ablation. This combination has produced high success rates and low serious complication rates. 

Support from the hospital is also instrumental for any successful program. Our hospital administration has supported us by conducting direct public seminars. Community outreach is important for the enrollment of patients from a larger geographical area, and a centralized “hotline” office provides screening of callers. Our patient seminars encompass statewide coverage as well as encourage participation from neighboring states. From the seminars we have conducted thus far, we have found that the majority of patients attending are typically dissatisfied by their AF treatment. Namely, they cite that many of their physicians do not appreciate the value of their patients’ reduced QOL. Therefore, an improvement in QOL has been the biggest draw for these patients. From each seminar, which is typically attended by 200-300 people, we enroll 15-20 patients. 

Conclusion

The hybrid procedure for the treatment of persistent and longstanding persistent AF is finding a growing role in the spectrum of AF management. It accomplishes similar success rates as the open maze procedure, but is less invasive and more effective than a catheter-based approach. It is a two-stage procedure that requires dedicated and experience operators. The VATS Maze stage requires a surgeon with cardiothoracic skills, and the catheter stage requires electrophysiologists with an understanding of complex left atrial mapping. Minimizing procedure time is key, and separating the two stages can accomplish this as well as achieve better long-term outcomes.

Even with the complex mission of a hybrid procedure, we believe that a successful program can be accomplished in a facility of any size, as long as the key elements such as a dedicated multidisciplinary team and supportive hospital management are in place. A skillful and experienced surgeon is a critical member of the team. As such, the “program” can actually be expanded to include nearby hospitals, as the referring electrophysiologists can perform the second stage at their own facility, and hence, maintain the continuity of care of the patient.

Lastly, it is important to remember that some patients with persistent and longstanding persistent AF frequently report reduced QOL and dissatisfaction of their existing AF treatment. Therefore, direct patient marketing is key for successful patient recruitment to a hybrid program.

Disclosures: The authors have no conflicts of interest to report regarding the content herein. Outside the submitted work, Dr. Dunnington reports consulting, proctoring, speakers' bureau, and grant from AtriCure. Ms. Pierce reports personal fees from AtriCure for consulting.

References

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