Clinical and Operational Considerations for the Hansen Medical Sensei Robotic Catheter System

Introduction

In December 2011, we completed the final phase of a construction initiative to bring a state of the art Arrhythmia Center to Indiana University Health La Porte Hospital. This project included construction of procedural labs, holding areas, clinic space and offices. We equipped the rooms with sophisticated and integrated imaging, monitoring, mapping and communication systems (Table 1). During the planning stages of the project, I had many conversations concerning the addition of a robotic system to our site. Our hospital had recently added the da Vinci Robotics System to our surgical department, so the addition of a robot to the Arrhythmia Center would only complement the technological vision of the hospital.

Since space was limited in the new lab and the new room could not be limited to ablation only, the Sensei^® X Robotic Catheter System (Hansen Medical, Mountain View, CA) proved to be the best choice for us. Not only did it meet our requirements for space and ease of use, but also for our budget concerns.

Case Study (sidebar)

The patient is a 64-year-old male with a history of highly symptomatic, paroxysmal atrial fibrillation dating back to 2000. He had failed diltiazem, metoprolol and propafenone in the past, averaging four episodes per year with one to two necessitating admissions. In 2004, at age 58, he underwent a limited “focal” pulmonary vein isolation procedure at a nearby university (“spot” RF applications guided by standard Lasso catheter mapping of the pulmonary veins).

Over the next six years, episodes increased in frequency and duration, with an atrial fibrillation burden of approximately six episodes per year. Initially, the patient tried the “pill in the pocket” approach with diltiazem and flecainide. This was generally unsuccessful.

He ultimately presented to Indiana University La Porte Hospital in atrial fibrillation with a ventricular response rate of 100 to 160 bpm. In May 2010, after a long discussion of the merits of chronic suppressive anti-arrhythmic medication versus catheter ablation, he elected to try medication. Over the ensuing fifteen months, he failed propafenone SR, diltiazem, flecainide and dronedarone secondary to lack of efficacy and/or side effects. His symptoms of rapid palpitations, dyspnea and episodic presyncope became worse with recurrent spells of longer duration.

On July 15, 2011, the patient requested a repeat ablation attempt after a thorough discussion of the newer techniques since his last procedure (including three-dimensional mapping with Biosense Webster’s Carto 3, Fast Activation Mapping, Biosense Webster’s CartoSound intracardiac mapping and robotic-assisted navigation). Risks and benefits were clearly defined and he consented.

The baseline work-up included an echocardiogram, which showed normal left ventricular function, mild LVH (1.3 cm), mild left atrial enlargement (4.4 cm), and a left atrial volume index of 50 ml. A nuclear stress test was negative for ischemia or infarction with a normal ejection fraction of 60%. A baseline Holter showed sinus rhythm with multiple PACs and multiple, short runs of atrial tachycardia, presumably of pulmonary vein origin. The patient’s CHADS score was 1 (hypertension).

On August 6, 2011, the patient underwent five pulmonary vein isolations (two left and three rights) using wide area circumferential ablation, with Biosense Webster’s ThermoCool irrigated catheter guided by Hansen Medical’s Sensei robotic navigation system. (Figure 1) Additional “spot” applications were delivered outside of the pulmonary vein ostium as guided by Lasso electrograms (Figures 2 and 3). Esophageal temperature was monitored con- tinuously by probe.

At the end of the procedure, all pulmonary vein potentials were eliminated and exit and entrance block was verified. Atrial fibrillation could not be in- duced despite an aggressive stimulation protocol consisting of right and left atrial burst pacing to 2:1 capture (cycle length 180 msecs) and S1-S5 coupled to refractoriness in the right and left atrium (both drug free and on graded isoproterenol doses of 5 mcg/min, 10 mcg/min, and 20 mcg/min).

The patient has been followed clinically for seven months without recur- rence, and 48-hour Holter monitoring (done twice since the ablation) has shown only rare PACs (<3 in 48 hours) and no recurrence of atrial fibrillation.

Operational Considerations

Initial experience with Sensei at our facility was with Carto 3 (Biosense Webster, Inc., a Johnson & Johnson company, Diamond Bar, CA). We were aware that there isn’t the formal “cohesion” between the map and robot that is seen with Sensei and the EnSite NavX system (St. Jude Medical, St. Paul, MN). However, this was the mapping system that we had already chosen for the lab and felt comfortable that there would be no issues. A review of the literature as well as peer recommendations proved the efficacy of utilizing Carto 3 with Sensei. Teamwork is necessary between the physician and Carto clinical specialist to align and manipulate the maps for the greatest benefit during cases. However, all other processes remain the same.

The CoHesion^™ 3D Visualization Module is an integral part of Sensei that allows integration of the system to the EnSite NavX system. This assists with remote catheter navigation of the Artisan Control Catheter (Hansen Medical). Three-dimensional data from EnSite is imported into Sensei and updated as the EnSite map changes. This provides synchronization of images between the two systems. EnSite NavX has now been purchased for utilization in our facility as we want to be able to utilize Sensei to its fullest capabilities. Although a duplication of systems for our facility, each (i.e., Carto 3 and EnSite NavX) have their own distinct advantages with Sensei and with other ablation cases.

Physician Credentialing

Physician credentialing became an issue at our facility and it actually delayed our first cases. Although we surveyed the majority of sites utilizing Sensei and found that there were no specific credentialing requirements for the medical staff, our Credentialing Committee required it. Specific credentialing was needed for the da Vinci Robotics System in the surgical department, and the Credentialing Committee felt it necessary to require credentialing for Sensei. We emphasized that this was an adjunct to currently credentialed procedure lists, but were not successful in eliminating the need for special credentialing. The committee agreed on the following credentialing criteria for a physician at this facility:

• Training can be demonstrated in one of the following ways:
• Successful completion of the physician certification training at a Hansen Training Center
• Successful completion of three (3) ablations for arrhythmias on the right side of the heart prior to crossing the septum with the syste

Or

• Experience must be demonstrated in the following ways:
• Experience in Sensei Robotic Catheter System procedures or
• Successful completion of the physician certification training at a Hansen Training Center and successful completion of three (3) ablations for arrhythmias on the right side of the heart prior to crossing the septum utilizing the system.

Five “right-sided” ablations were performed successfully with Sensei, in the presence of Sensei clinical specialists, in order to meet the requirements of credentialing. Documentation was presented to the committee on each case. No adverse events were noted in any of the first five.

Physician/Colleague Education and Training

Special training sessions for our physician and colleagues were held on site at our facility as well as for identified personnel at Methodist Hospital in Houston, Texas. Hansen Medical has very specific guidelines concerning training for all personnel involved.

Intense training was done for Dr. Dixon and two colleagues (an EP Rad Tech and an RN) in Houston at the Methodist Hospital Hansen Training Center. The two-day program involved classroom, simulators, training in the animal lab, and observation of actual cases. This program was conducted by clinical specialists from Hansen Medical.

Additional training was held for the remainder of the colleagues in our facility. Hansen Medical prepared education checklists that were utilized during the training for skills assessment. Multiple clinical specialists were on site to allow for smaller ratios of colleagues to specialists. Simulators were utilized so that colleagues would be able to “drive” a catheter. In addition to demonstrations by clinical specialists from the company, colleagues completed return demonstrations on the following components:

• Equipment setup and connection of Remote Catheter Manipulator (RCM) to procedure table
• Operation of the system including “boot-up” process and description of the component parts
• Demonstration of sheath flushing, Gaymar device use and set-up, draping procedures, mounting of the sheath on the RCM
• Troubleshooting measures
• Procedural steps for pre, intra and post procedure

Equipment Requirements

One of the advantages of the Sensei system was that it could easily fit into our space. When the control room was designed, I left a space open for placement of the physician workstation. The system consists of only these three component parts:

• Physician Workstation – This fits in a spot approximately 56” in length and 27” deep. There are three display screens (the main display screen is for the “control view” of the Artisan Catheter, the left and right screens are for recording, mapping, monitoring, and imaging systems), the Instinctive Motion Controller (IMC), the Control Pendant and the touch screen on this console.
• Bedside Subsystem – This includes the Bedside Electronic Module and the RCM.
• Electronics Rack – This contains all system software and computer hardware as well as the UPS. This was placed in the Equipment Room.

Besides the items mentioned above, there were some additional considerations made for the system. An additional foot pedal for fluoroscopy was added to the console so the physician could operate this remotely. Our construction foreman and an engineer from one of our other companies fabricated a base stand for the RCM, as we take it off the table between cases. Additional wiring for the system was placed through the electrical “doghouse” located at the base of the table. The system was also integrated into our Carrot Medical monitoring system for display in the procedure room.

Supplies

Another advantage of the Sensei system was that it allowed our physicians to utilize the ablating catheters of their choice. This was important to us, as it did not limit our preferences. Only a few items were needed in addition to the standard supplies we utilize for non-robotic cases. The accessory items necessary when using the robot include the following:

• A disposable single-use Artisan Control Catheter
• Sterile Drape Kit (Hansen Medical)
• Two pressurized flush lines for connection to the Artisan Catheter (hospital stock)
• A 14F femoral Introducer Sheath (we utilize St. Jude Medical’s Fast-Cath 14F Hemostasis Introducer)

Charging and Reimbursement

There currently is no specific reimbursement for utilization of the robotics system during complex ablation. As of this writing, there are no CPT or pass-through codes (C-Codes) for the additional equipment, either. At our facility, all our supply costs are “rolled up” into the various procedure charges that are attached to the approved CPT codes except for the pass-through codes (C-Codes). In order to cover the additional costs of the robotic system, we created a second line item charge for our CDM that included the additional supply costs. Now, when charging an ablation case, colleagues have an option to either choose “ablation” or “ablation with robot.”

Summary

We have done a total of 20 robotic cases since system implementation in our lab. After the initial right-sided cases, five atrial fibrillation ablations have been done to date. The “learning curve” of the robot is steep, but as more cases have been done, procedure and fluoroscopy times have been shortened.

From the physician standpoint, the most impressive result is the intimate contact with the atrial myocardium that the Sensei provides. Ablation lines are made efficiently and effectively without gaps. “Single Pass Isolation” of veins is quite common with the Sensei. The IntelliSense feature gives constant and accurate feedback of tissue contact. Complex catheter manipulations can be accomplished with the robot that manual catheter manipulation cannot easily achieve. The operator is offered the benefits of improved efficacy, ablation while sitting, far less fluoroscopy exposure, and the ability to concentrate on tissue heating, esophageal temperature, and loss of pulmonary vein potentials while “knowing” the robotic system is securing the ablation catheter properly.

The Sensei will be an integral part of our complex ablation program. We are constantly performing case analysis in order to improve outcomes. Our initial experience has met our expectations.