Endovascular surgery credentialing training for vascular surgeons

Transcription

1 SPECIAl. ARTICLES Endovascular surgery credentialing training for vascular surgeons and Rodney A. White, MD, Thomas J. Fogarty, MD, William H. Baker, MD, Samuel S. Alto, MD and S. Timothy String, MD, Torrance, Redwood, and Los Angeles, Calif., Maywood, Ill., and Mobile, Ala. This article reviews the issues concerning credentialing and training of vascular surgeons for the use of endovascular surgical techniques. The guidelines are based on the expertise and experience acquired during vascular surgical training and outline the skills that must be developed and documented to ensure safe and efficacious application of the methods. The recommendations have been developed for vascular surgeons only and may not be applicable to other interventional specialties, which have different criteria for assessing the indications for and determining the utility of endovascular procedures. SURGICAL PERSPECTIVE OF ENDOVASCULAR SURGERY Endovascular surgery procedures involve techniques that achieve a therapeutic result by introducing instruments into the lumen of a vessel. The concept is founded on techniques that fracture and displace the plaque or that accomplish removal of lesions like an endarterectomy. Early attempts at endoluminal removal of plaque with various forms of strippers or grasping devices had limited use, because From the Division of Vascular Surgery, Harbor-UCLA Medical Center (Dr. White), Torrance, Sequoia Hospital (Dr. Fogarty), Redwood, Section of Vascular Surgery, Loyola University Medical Center (Dr. Baker), Maywood, Division of Vascular Surgery, UCLA Center for the Health Sciences (Dr. Aim), Los Angeles, and Vascular Surgery PC (Dr. String), Mobile. Reprint requests: Rodney A. White, MD, Harbor-UCLA Medical Center, I000 W. Carson St., Torrance, CA *Prepared by the Ad Hoc Committee on Endovascular Surgery Credentialing and Training for Vascular Surgeons, Society for Vascular Surgery/International Society for Cardiovascular Surgery, North American Chapter. J VAsc Su:m 1993;17: Copyright 1993 by The Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter /93/$ /9/46014 the patency rates in some applications were not comparable to bypass reconstruction. A resurgence of interest in these techniques has occurred with the advent of miniaturized catheter technologies that selectively displace or remove lesions without requiring exposure of the vessels. Balloon catheter embolectomy and thrombectomy reported by Fogarty et al.: in 1963 began the evolution of endovascular technology; this was the first therapeutic use of a vascular catheter. The technique remains one of the most successfully and widely used endoluminal surgical methods. In 1964 Dotter and Judkins 2 introduced the concept of transktminal dilation with coaxial dilating catheters. Subsequent evolution of balloon angioplasty has been dramatic, with serial improvements in technique and devices. 3 Today the use and application to various lesions is still being defined as balloon technology continues to evolve based on identification of not only new technology and indications but also clinical limitations. In many respects the evolution of balloon dilation technology has been slow and mainly restricted to treatment of large vessel stenoses and short occlusions in the iliac arteries and selected short lesions in the coronary arteries. There are few reports of long-term success of balloon dilation of lesions for limb salvage either in small peripheral vessels or in long occlusions of larger vessels; thus the major application is for short lesions in large vessels with less severe vascular disease, that is, those seen in patients with claudication. For this reason the technique has had limited application in many vascular surgeons' practices in that it has been used only as an adjunct during bypass procedures. Otherwise, it has had a limited role in therapy of patients with severe symptoms (those with rest pain and gangrene) who require major revascularization. In 1095

2 1096 White et al. June 1993 general most endoluminal procedures have been initially used and evaluated by interventional specialists other than surgeons, such as radiologists and cardiologists, in the treatment of patients with less severe disease. This developmental history has important implications in credentialing and training guidelines, particularly for vascular surgeons who have a tradition of evaluating, and in treating and monitoring most patients with peripheral vascular disease. These skills have been developed through years of experience in treating patients with severe disease and in performing complicated vascular reconstructions. Surgeons are clearly most experienced with the anatomic disease and the patient's response to a variety of treatment methods. Surgeons are experienced with long-term follow-up and observation of both the natural history of arteriosclerosis and the response to reconstructive procedures. For these reasons surgeons have an important perspective on the role of current endovascular methods, particularly because surgical knowledge and skill are relied on'or correction of the complications encountered during endovascular procedures. Throughout the evolution of general vascular surgery as a separate subspeciality (which is currently recognized by the American Board of Surgery with certificates of special or added qualification), several key components related to the diagnosis and treatment of vascular disease have been emphasized. These include knowledge of the physiology, anatomy, pathologic process, vascular disease, development of diagnostic skills, carefully considered use of all interventional methods including balloon- and catheter-based therapies, pathophysiologic and anatomic correlation of symptoms with surgical observations, and long-term follow-up of the natural history of atherosclerotic disease and interventional therapies and treatment of complications. Vascular surgeons pioneered and are well versed in the performance and interpretation of noninvasive vascular diagnostic procedures. With particular reference to endovascular techniques, vascular surgeons routinely interpret and perform contrast arteriography, particularly in the operating room, and introduce intravascular catheters such as thrombectomy and dilation devices, vena cava filters, intraluminal shunts, arterial cannulas, and various forms of intravascular access devices that are inserted percutaneously with conventional arterial puncture and guide wire techniques. NATIONAL GUIDELINES FOR PHYSICIAN CREDENTIALING The Joint Commission on Accreditation of Health Care Organizations requires that specific privileges be delineated for each hospital staff member. Each hospital is required to monitor the appropriateness of care provided by physicians and to provide mechanisms to assess new technologies before they can be used clinically. These directives have been accommodated in most instances by establishing department guidelines for new physicians or for physicians using techniques or methods that they have not previously used. For surgical procedures this usually entails observation of a specified number of procedures by a proctor and reporting of procedure outcome both initially and after long-term follow-up. Qualifications required for a physician to perform a procedure are based on skills acquired during residency or fellowship training, a supervised preceptorship, or approved courses when appropriate. Frequently expertise in new technologies is developed during initial experimental,trials of devices by physicians performing the studies trader the auspices of Institutional Review Boards and Food and Drug Administration investigational programs. Thus the means by which physicians obtain appropriate training can follow a number of avenues from formal training to acquisition of skills during initial experi~ mental and clinical trials of devices for efficacy anc~ safety. SUBSPECIALITY GUIDELINES FOR PHYSICIAN CREDENTIALING Endovascular device development and application has been influenced by various subspecialties, primarily surgeons, radiologists, and cardiologists in the context of how the methods affect each group's primary patient population. Each has independently arrived at training, credentialing, quality assurance, and education guidelines for applications solely within their discipline, that is, coronary catheterization, cerebral angiography, and so on. Controversy and uncertainty have arisen when guidelines are developed for areas of mutual interest, that is, peripheral angioplasty. This controversy is complicated further because different patient groups are treated, different criteria of success are used, and each specialty emphasizes credentialing criteria based on their tradition. Patients who are symptom free (minimal disease) or those with intermittent claudication (moderate dis-

3 Volume 17, Number 6 White et al Table I. Number of interventions SCV1R SCAI A CC* AHA * SVS/ISCVS * Diagnostic and therapeutic angiograms /50t t Angioplasties 25 50/25t 50/25t 50/25t 10-15t Live demo Yes Yes Yes Yes Yes SCVIR, Society of Cardiovascular and Interventional Radiology; SCA/, Society for Cardiac Angiography and Interventions; ACC, American College of Cardiology; AHA, American Heart Association; SVS/ISCVS, Society for Vascular Surgery/International Society for Cardiovascular Surgery. *Includes knowledge of thrombolysis or thrombolytic therapy. tas primary interventionalist. ease) or limb-threatening ischemia (most severe disease) can all be treated by identical techniques. The short- and long-term success in each of these groups is expected to be different. Furthermore, whereas immediate hemodynamic or angiographic success is measured by some, long-term clinical evaluation, patency by duplex scanning or hemodynamic success as measured in a noninvasive vascular laboratory is emphasized by others. Each specialty has established preliminary criteria for application of the methods based on their interest and ability to treat a particular segment of the patient population and their tradition in equating expertise with numbers of procedures. ~8 Emphasis in several of these documents focuses on credentials for percutaneous transluminal angioplasty, whereas the vascular surgery perspective is to more broadly address a ~arge number of methods and techniques being developed. Guidelines for procedures in addition to percutaneous transluminai angioplasty will obviously evolve as technology advances and as utility increases. Table I summarizes the number of recommended interventions for credentialing by the various groups, including those recommended in this document for vascular surgeons. The particular guidelines for each subspecialty should be benchmarks for physicians and hospitals in determining the appropriateness of individuals in each specialty to safely and effectively perform procedures. This is particularly important because each subspecialty's guidelines have been established and will evolve to accommodate new technologies predicated on the background, training, skills, and techniques used by physicians in each specialty. For similar reasons a particular subspecialty's guidelines should not be used to determine the appropriateness of application or credentialing for another subspecialty that has an entirely different perspective regarding training, methods of application, or indications for the procedure. Controversial differences regard- ing indications, efficacy, and the like are issues that should be addressed separately from credentialing criteria and be determined with randomized clinical data reported with recommended standards. 9,1 VASCULAR SURGERY CREDENTIALING GUIDELINES Credentialing for vascular surgeons who use endovascular techniques should be by one of two established methods. Privileges should be granted or renewed either by the chief of the surgical services or by a hospital credentialing committee (whichever mechanism is operative in a particular institution) at the time of annual renewal of surgical privileges and reappointment to the medical staff. Privileges may be granted on the basis of training acquired during a vascular fellowship (residency) that verifies educational experience, by past practice experience, or by a senior surgeon or other interventionalist trained and experienced in the methods. Renewal of privileges is the simplest consideration and should be determined on the basis of quality assurance monitoring, morbidity and mortality surveillance, and maintenance of skills. Each individual's competence should be determined by assessing the number of procedures, the pathologic condition and indications for procedures, complications, and at least a 30-day assessment of success (patency) of procedures determined by use of objective methods (ankle/brachial indexes, duplex scanpang, or angiography). Obviously, ongoing life-table analysis of results is desirable for assessing outcome of procedures in the optimal scenario and should be performed for determining the use of individual procedures. Assessment of the use of particular procedures is not a focus for this discussion and is being addressed in another document. 1 Each of the factors described for determining renewal of privileges is obviously an essential component of a chairman's recommendation regarding

4 1098 White et al. June 1993 Table II. Factors determining percutaneous or "open" access Lesion location Size of device Patient variables Body habitus (obesity or abdominal pannus) Associated diseases (diabetes and the like) Steroid therapy Endovascular therapy of a second lesion combined with a conventional reconstruction Physician choice or training Failure or complication of percutaneous puncture renewal. Additional factors such as credentialing based on course or symposium experience, didactic and hands-on.experience, and in vitro and in vivo animal model or patient experience is most appropriately considered in light of the complexity of the procedure, the training and experience of the physician and other relevant factors at the time the consideration is being made. One- or 2-day training in the use of a new device may be appropriate for experienced surgeons familiar with all aspects of endovascular device use, although this limited exposure is inadequate under most circumstances for surgeons with no experience. Although much of the training of a vascular surgeon may be based on specific skills that will be addressed in the following discussion, each is eunumerated for completeness of the consideration. It is important to recognize that vascular surgeons not only have special expertise in correlating operative anatomy with preoperative diagnostic information but also have experience with long-term follow-up and pathologic correlation in failed procedures. Vascular surgeons are the only specialists qualified to evaluate and treat limb- and life-threatening complications of endovascular procedures. The experience acquired regarding use, indications, and appropriate anticipation of possible complications makes vascular surgical consultation an important component of all endovascular therapy. In many respects the vascular surgical position on credentials for training is influenced by these factors and must consider the role of experience acquired during training on recommendations for certifying additional skills required for endovascular methods. Lesion Access Endovascular interventions may be performed with either percutaneous access techniques or by introducing the devices through an arteriotomy in the exposed vessels. The preferred method is deter- mined by many variables (Table II) although the major considerations at present include the diameter of the devices, the location of the lesion related to the access site, and variables such as the patient's body habitus and associated diseases. Access by surgical exposure is performed in the minority of instances and is primarily considered within the purview of the surgeon. Training for percutaneous introduction of devices deserves more detailed consideration and is more controversial because several specialities use these techniques in various locations, that is, radiology suites, cardiac catheterization laboratories, and operating rooms. Percutaneous introduction methods uniformly use tile Seldinger technique for performing the initial entry into the vessel, n A major segment of the training of all concerned subspecialities entails use of this method. The radiologist and cardiologist perform most of their procedures via the femoral or axillary vessels. Although there are a limited number of femoral or axillary percutaneous procedures done during general and vascular surgery training (i.e., angiography for trauma), this method is used broadly for introduction of other types of devices such as subclavian and internal jugular catheters for dialysis access, insertion of Groshong (Bard Access Systems, Salt Lake City, Utah), Swan-Ganz (Baxter Healthcare Corp., Edwards Div., Santa Ana, Calif.), and central venous pressure monitoring catheters and vena cava filters. Percutaneous access techniques at,,',/ also used during general surgical training for introducing devices such as gastrostomies or enterostomies, and for chemotherapy and alimentation vascular access catheters. Because of this need most vascular surgeons have significant experience with percutaneous vascular access catheter introduction and are fully qualified to perform percutaneous endovascular access if they have supplemented this basic training with endovascular experience with femoral artery punctures. If the surgeon has no experience, development of this skill should be enhanced by performing 10 to 15 percutaneous insertions in collaboration with a physician trained in this technique. Special skills are required for percutaneous puncture of selected vessels such as the popliteal artery or for antegrade entry into the superficial femoral artery. Additional training is required to ensure mastery of these specialized access approaches. Image acquisition and interpretation Performance of endovascular procedures relies heavily on obtaining high-quality radiographic, an-

5 Volume 17, Number 6 White et al gioscopic, or intraluminal ultrasound images of the vascular segments being treated before, during, and after the interventions. 9 The imaging equipment, which is an important component of the procedures, is addressed in a subsequent section. The performance, interpretation, and determination of the use for a particular imaging method are essential prerequisites for credentialing approval. Vascular surgeons are familiar with using radiologic imaging for assessing vascular anatomy before, during, and after interventions, and, for placing venous access, Groshong and Vas-Cath catheters (Vas-Cath, Inc., Ontario, Canada), and vena cava filters. Many vascular surgeons are skilled at passing intraluminal imaging devices such as angioscopes and intraluminal ultrasound catheters. Skill to use imaging devices can be obtained after didactic and hands-on instructions that demonstrate the use and interpretation of acquired data. These skills may be acquired during fellowship training, during supervised intraoperative application by an experienced interventionalist (surgeon, radiologist, cardiologist), or through specialized training courses. Performance of radiologic studies is a more complex issue related to multispecialty application, safety considerations regarding radiation, and speciality training required for operation and interpretation of sophisticated imaging systems. Vascular surgeons are highly qualified in the interpretation of,ascuiar contrast studies, although there is variability in the experience of performing percutaneous angiography. Many older surgeons were trained in angiography and for many years performed their own procedures, and a limited number of vascular surgeons still routinely perform arteriographic studies. In general, vascular surgeons independently interpret and consult with a vascular radiologist regarding angiographic studies done outside of the operating room. The surgeon also performs and interprets arteriography in the operating room in addition to evaluations performed before and after reconstructive procedures. Surgeons should have performed at least 50 diagnostic or therapeutic artefiographic studies if credentials are to be granted without previous documented experience in endovascular or angiographic training. An important consideration that will be expanded in a subsequent discussion is that not all operating rooms have high-quality x-ray fluoroscopy that can facilitate the performance and ensure the quality of certain types of interventions. For surgeons who are not trained in angiographic imaging, supervised training with an experienced interventionalist is recommended until the operator has demonstrated the ability to acquire high-quality images with a minimum of contrast agent and fluroscopic exposure. Concepts regarding radiation safety and x-ray exposure are understood by most vascular surgeons, although individual institutional guidelines developed to accommodate state licensing requirements for control and monitoring of radiation safety appropriately define the assessment of this knowledge. Performance ofpercutaneous radiographic imaging studies by a vascular surgeon in catheterization or radiologic laboratories outside the operating room deserves special consideration. Radiologic studies performed in these areas should be considered separately, because they include a combination of the issues regarding percutaneous access techniques and those described for intraoperative performance of imaging procedures. To perform procedures outside of the operating room, the surgeon should be able to document previous experience or training with a level of competence and safety confirmed by a physician with accepted credentials. Guide wire training Guide wires are used widely throughout medicine and surgery to establish channels through stenotic or occluded tubular structures and to guide passage of larger catheter devices. They have a particularly important role in endovascular interventions because they constitute the primary method for establishing intravascular access and are used to introduce, position, and manipulate endovascular devices. There are many types of guide wires with specific physical properties (flexibility, surface "wetability," configuration) that are used to enhance the precision of procedures. Safe introduction, passage, and positioning of guide wires requires expertise in imaging, technical skill, and judgement to enable safe and effective use. Guide wire use is a pivotal skill in the current "art" of endovascular intervention. A principle use of guide wires is for obtaining percutaneous access with the Seldinger technique. All vascular surgeons are familiar with and skilled in this method, as previously discussed. More sophisticated skills are required to perform guide wire cannulation of selected branch vessels (i.e., visceral or lumbar arteries) and these techniques constitute a major focus of training in interventional radiology programs. Special training is also required to develop the tactile skill needed to pass wires across tightly stenotic or occluded lesions without causing vessel perforation or dissection. These skills can only be learned

6 1100 White et al June 1993 during interventional procedures and may be acquired as part of a formal training program or be learned under the supervision of an experienced interventionalist in the operating room or in the radiology and cardiology suites. The skills are easily acquired by a vascular surgeon because tactile agility is a prerequisite for surgical expertise in general, and competence can be assessed and certified by an observer experienced in the methods. Knowledge regarding the various types of wire devices and information about their physical properties is easily obtained through several mechanisms including individual instruction, didactic lectures, hands-on symposia, and available literature. Specific device training Use of particular devices is predicated on the surgeon's ability to perform the basic endovascular maneuvers (lesion access, imaging, and guide wire passage) that have been discussed, a demonstration of knowledge of the function of and indications for the device, and familiarity with safety considerations pertinent to a particular instrument. In this regard most devices can be used without special certification after acquisition of the fundamental knowledge regarding the device. Specifically a trained vascular surgeon should be able to safely use angioscopes, intravascular ultrasound catheters, and the like without special instruction. Likewise, a new form of atherectomy catheter that is introduced over a guide wire can be safely used if the surgeon is experienced with atherectomy devices in general. Special concerns arise regarding certification for balloon angioplasty, lasers, and newer devices such as stents, and these will be addressed separately in the following discussions. Balloon angioplasty. Balloon angioplasty is the most widely used endovascular method and is considered the standard for comparing other interventional devices. Each subspeciaity has developed standards for application of this method as it applies to the specific field of interest, that is, cardiologist performing coronary angioplasty 12,13 or radiologists performing peripheral angioplasty, s Controversy arises when attempts are made to establish uniform guidelines for training and credentialing, which address the issues of subspecialties with diverse training programs and different methods of application of the devices. Most surgeons collaborate with an interventional radiologist who treats indicated lesions, that is, renal or other branch aortic vessels. There are, however, some surgeons who routinely perform balloon angioplasty and are highly skilled in its application. In addition, surgeons currently involved in performing other endovascular interventions routinely use balloon angioplasty as either primary therapy or in conjunction with other techniques. Thus there is wide variability in the current training and use of balloon angioplasty by surgeons, although all are well versed in determining the indications for and in treating the complications of balloon procedures. Establishing credentials for balloon angioplasty by vascular surgeons may be accomplished by several means. Previous experience or training verified by a: fellowship are obvious qualifications. For fitly trained vascular surgeons with no previous experience with balloon angioplasty during their fellowship, assistance and instruction by a trained interventionalist for 10 to 15 procedures is recommended. If no trained vascular surgeon is available at a particular institution to perform the training and supervision, it may be done by an interventional radiologist. Lasers. The primary considerations regarding the use of lasers are safety issues. Physicians, hospital personnel, and all individuals involved with these devices should be versed in laser safety. 14 In addition, laser facifities must be operated according to requirements established and overseen by a hospital safety committee. Issues regarding indications for the use of these devices should be determined by randomized clinical trials performed with the published guidelines.8,9 ~ Atherectomy, stents, and other devices and technologies. Many other devices and technologies are being evaluated for endovascular application whereas FDA approvals and preliminary reports of clinical success are generating widespread interest in use. Atherectomy catheters, both directional and rotational varieties, are being evaluated for treating peripheral arterial lesions. Variable results have been reported although improved success in selected lesions has been demonstrated when procedures are performed with high-quality imaging to assure adequate lesion removal) s Intravascular stents are also being investigated widely for treatment of lesions in the aorta and iliac and renal arteries. Preliminary results of studies that use these devices in larger-diameter (greater than 7 cm diameter) arteries is quite favorable, although application to smaller arteries is less optimistic and will require significant additional investigation and development. Although stents have been used primarily by radiologists and cardiologists, surgical interest is increasing as they are used as the fixation mechanism for intraluminal aortic grafts. Many

7 Volume 17, Number 6 White et al prototype systems for intraluminal graft deployment are being developed with surgeons leading this effort. This technique may be the first endovascular method that stimulates widespread surgical involvement, particularly because it encompasses the treatment of aortic and large-vessel aneurysms, which is currently considered solely within the domain of vascular surgeons. Developments in endovascular technologies not only involve devices but also pharmacologic agents such as thrombolytics. Drug therapy has not been addressed in most credentialing documents but constitutes an important therapeutic method that deserves ongoing evaluation. From a surgical perspective knowledge of drug therapy is rounnely incorporated in all vascular surgical training programs and is continually updated as advances occur. Endovascular credentialing should include documentation of knowledge of thrombolysis and thrombolytic therapy and performance of thrombolysis procedures. As each new method emerges the question arises: What constitutes adequate training for surgeons planning to use the device clinically? In most instances a surgeon trained in endovascular techniques can quickly adapt to new devices and must be trained only in specific safety issues or limitations regarding indications. This training can usually be accomplished by a didactic lecture session or in vitro ~,r in vivo animal laboratory training. Interventional imaging modalities Although imaging techniques have been discussed at various points throughout this article, it is appropriate to emphasize certain pertinent issues in a separate discussion because imaging plays a vital role in endovascular technologies. The topic is particularly relevant, because much of the current data regarding angioplasty results and the imaging of current interventional methods is based on anglographic visualization. There can be a difference in the quality of images obtained with the C-arm fluoroscopic units available in most operating rooms compared with the fixed, high-resolution, imaged-enhanced systems in many interventional radiology and cardiology suites. New C-arm units have overcome most previous limitations and are becoming readily available. Although it is paramount that good imaging methods be available (in particular, freeze-frame and road-mapping techniques) to obtain reproducible, high-quality results with endovascular devices, it is becoming increasingly apparent that angiography is limited in the degree of precision that it provides for guiding insertion of devices, and in determining the amount of a lesion to be removed. This is particularly pertinent, because there is significant variation between estimates of luminal cross-sectional area obtained with intravascular ultrasound (IVUS) and conventional arteriographic imaging} 6,17 The discrepancy has been documented by many studies and is exemplified by the finding that arteriography significantly overestimates the amount of lesion removed and the residual lumen size compared with that obtained by IVUS, which accurately assesses the plaque volume that remains compared with the area encompassed by the vessel wall. The concept of lesion quantitation with IVUS rather than arteriography is not accepted as part of the conventional approach and will require welldesigned studies to establish that IVUS enhances the catheter guidance and ultimately long-term patency of recanalizations. CONCLUSIONS Endovascular interventions have completed their initial evolution and are now developing to a point where vascular surgical use of the methods for treating patients with symptomatic occlusive disease may be on the horizon. Conventional vascular surgery training includes evaluation of the role and application of surgical and nonsurgical measures, and endoluminal techniques, although use of endovascular techniques has been limited. As the endovascular technologies have improved, vascular fellowship training programs have incorporated them into the programs. In this regard most vascular surgeons have the skills required for the application of endovascular technologies, and relatively few surgeons with limited experience will require intensive training to adopt these methods. The most important factor in determining the appropriate use of endovascular techniques is physician judgement and patient selection and not necessarily the number of procedures performed. Credentialing of qualified surgeons can be accomplished by obtaining experience with the techniques, supervision by a trained endoluminal interventionalist, or as part of a fellowship training program. Surgical correction of endovascular complications remains solely within the domain of the vascular surgeon, and is a compelling reason for their continued involvement in selection of patients, determining indications and in assessing the applicability of new technologies and helping in long-term patient care.

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