Simulation Training in 2005
In the near future, simulation training will have a significant impact on the way we learn to execute new procedures.
Turn the clock ahead 2 years. The patient on whom you are about to operate is ready, and you have several decisions to make. The initial strategy has been mapped out in your mind, but things do not always go as planned, and you must be able to adapt to a changing situation and environment. The diagnostic digital subtraction angiogram has been programmed into ?SimVasc 5? (a representation of a potential future technology). You don your lead, gown, and gloves, and step up to the operating table. The puncture site has been strategized for the left femoral artery approach, allowing you to treat the right superficial femoral artery using a crossover technique, and also to address the left renal artery stenosis with a balloon and stent.
As you feel the pulse, an 18-gauge needle is utilized to enter the femoral artery with the short sheath wire and 6-F sheath. Heparin is administered as you attach the side port to the pressure manifold. A waveform appears on your monitoring screen, and you know that you are in the native arterial lumen. As you begin to pass the 6-F pigtail catheter and soft-tipped J guidewire, you encounter resistance as the fluoroscope demonstrates considerable tortuosity in the left common iliac artery. Instead of changing to a hydrophilic guidewire and a 6-F Judkins (Cordis Corporation, a Johnson & Johnson company, Miami, FL) right coronary catheter, you force the pigtail catheter, and suddenly you are in trouble. The catheter is subintimal in the abdominal aorta, and you have lost flow. As you remove the catheter and guidewire, you notice that the pressure waveform is damped and that you have effectively lost the pulse. What began as an elective procedure has turned into a potential open operation. Your heart races and you feel your own catecholamine surge as you decide what the next step should be.
The clock is ticking and you are faced with many decisions, including fluoroscopy time, best utilization of resources, contrast issues, and how you will successfully complete the procedure and get to your office on time. The patient is unaware that anything is wrong, but you and your staff know that there is a problem and each of you is searching for the next step in the decision-making process. Your assistants will judge you based on your decisions as they compare your skills to those of other operators with whom they work. The cost of the procedure suddenly becomes more of an issue because the wrong choice of guidewire, catheter, or stent will adversely affect the fixed DRG reimbursement for the case.
The situation is real—almost. It is real in that the decisions that you are about to make will influence how the procedure turns out. It is not real in that you are using a simulator instead of working on a real patient. The simulator consists of a module into which a sheath is inserted to access the virtual anatomy. The operator can then decide which catheters and guidewires would be appropriate for the given anatomy. Because the anatomy can be preprogrammed based on the patient’s actual digital subtraction angiogram, the operator may actually perform the case on the simulator before the case is performed on the live patient. This enables the operator to attempt different techniques, wires, catheters, and stents before the devices are actually opened and utilized on the patient. Thus, mistakes in judgment can be corrected before the actual procedure occurs, which allows the patient to undergo the procedure without being an integral part of the learning curve for the practicing endovascular physician. Because the simulator is capable of haptic feedback, the operator can easily distinguish between the tactile properties of various catheters and wires (eg, a 5-F catheter has distinctly different tactile properties than a 6-F catheter). In essence, the operator can perform the procedure dozens of times on the simulator before applying the techniques on the patient. The benefits include more efficient use of resources (ie, products that will not work in a particular case are not used, less radiation, and less time in the lab to perform the procedure).
ENDOVASCULAR DECISION MAKING
The choice of technique in a given situation can be made on the basis of the patient’s actual digital subtraction angiogram, which has been applied to the simulator. Haptic feedback-collision detection and forced feedback permit you to feel the difference between successful deployment of a catheter and wire while you observe the image on the screen in front of you without actually being exposed to radiation. This benefits you because the LD 50 for radiation is linear and cumulative throughout your career. Likewise, it benefits your staff, which is exposed with you during the actual case, and it further benefits patients who undergo multiple procedures during their atherosclerotic lifetime.
The decision-making process also includes the correct choice of stents. Misplacements due to errors in judgment incrementally increase case costs because each stent can cost thousands of dollars. Deployment and correct apposition of the stent will influence the success of the case and also force you to adapt to your own errors in judgment because, once they are deployed, there is no ability to recapture or move them.
WHERE ARE WE NOW AND WHERE ARE WE GOING?
Currently, there are many experts in the field on endovascular medicine. They have the ability and know-how to decide what needs to be done and which products to use. As the patient population requiring treatment grows exponentially in the next 10 years, we will need to compress the learning curve to train more endovascular operators. Because the system is driven by profit margins, it will be imperative to scrutinize individual operators based on their utilization of resources, time to complete the cases, fluoroscopy time, and successful outcomes. The individuals with good ratings in all of these categories will set the standard for other physicians, hospitals, and patient care.
Because of diversification in training, we are currently experiencing a situation in which endovascular procedures are carried out in three areas—the radiology suite, the cardiac catheterization lab, and in the operating room. The diversification in imaging equipment is haphazard, with some operators using a C-arm, others using cineangiography, and still others using state-of-the-art digitally equipped rooms and user-friendly operating tables. In effect, the field of endovascular surgery is emerging from its infancy.
Just as we mature in the field of virtual reality training applications, the next evolutionary challenge will incorporate the best of all of our combined technologies. In medicine, we are the benefactors of the technological improvements, which the military began to develop in the 1970s. Remote telepresence (ie, operating from a distant site, image-guided systems, and six degrees of freedom allowing 1,200 possible angles and positions) may indeed replace issues such as haptic feedback, the need for stents, balloons, and guidewires in the future. A futuristic operating room using the Cyberknife (Accuray, Inc., Sunnyvale, CA) may ultimately enable the endovascular surgeon of the future to operate in an extravascular environment while working on the endovascular disease process. The ability for a linear accelerator to treat lesions with submillimeter accuracy may indeed result in a procedure with no blood, no anesthesia, and no recovery time. This system can track moving structures to allow automatic compensation for vessel movement. As refinement in CT angiography is nearly complete, this technology, in conjunction with the ability of the operator to perform Cyberknife radiosurgery, has the capacity to further revolutionize the management of patients with cardiovascular and peripheral vascular disease.
As we are poised to offer simulation training for endovascular techniques, the next step is hauntingly near. The technology exists with regard to x-ray equipment, catheters, guidewires, endografts, stents, protection devices, and embolectomy systems. Newer devices are in the engineering pipeline. As physicians, we need to stay focused on the mission at hand. The politics of who does the procedure and where it is done will pass and become even more trivial as we learn and teach other physicians these techniques. This is what makes it exciting and relevant to patient care.
Simulation training is about to emerge in an important way to overcome some of our current critical issues in endovascular surgery. And when it does, we will all be benefactors of this wonderful training tool.
James A.M. Smith, DO, is President, Kansas endoVascular Medicine Associates, Wichita, Kansas. He holds no financial interest in any product or manufacturer mentioned herein. Dr. Smith may be reached at (316) 721-1200; firstname.lastname@example.org.
David H. Deaton, MD, is Chief of Endovascular Surgery at Georgetown University Hospital in Washington, DC. He holds no financial interest in any product or manufacturer mentioned herein. Dr. Deaton may be reached at (202) 444-1265; email@example.com.