- Email: [email protected]
Can Interventionalists do Endovascular Aortic Aneurysm Repair As Well As Vascular Surgeons?
Advances in Surgery j (2014) j–j
ADVANCES IN SURGERY Can Interventionalists do Endovascular Aortic Aneurysm Repair As Well As Vascular Surgeons? Tazo Inui, MD, Dennis F. Bandyk, MD* Division of Vascular & Endovascular Surgery, Sulpizio Cardiovascular Center, University of California - San Diego School of Medicine, 9434 Medical Center Drive, La Jolla, CA 92037, USA
Keywords
Abdominal aortic aneurysm Endovascular aneurysm repair Vascular surgery Interventional radiology System utilization Multispecialty team
Key points
Most of the abdominal aortic aneurysms are currently repaired using an endovascular stent graft implanted via a femoral artery approach, often via percutaneous access.
Vascular surgeons and interventional radiologists/cardiologists are performing endovascular aortic aneurysm repairs (EVARs) in large numbers.
Comparative effectiveness research suggests EVAR performed by vascular surgeons is associated with lower mortality, shorter length of stay, and lower costs compared with the repair performed by interventional radiologists or cardiologists.
Interventionists who perform EVAR may optimize their care by working with a vascular surgeon as a multidisciplinary team, thereby using all of an institution’s resources.
BACKGROUND Abdominal aortic aneurysm (AAA) is a focal degeneration of the aorta present in 1% to 5% of the population, with rupture being the most common complication resulting in approximately 15,000 deaths per annum in the United States [1]. Screening for AAA is now recommended in selected high-risk populations: men older than 65 years, men and women who have smoked tobacco, or individuals with a family history of AAA. The era of AAA repair began in 1952 *Corresponding author. Division of Vascular & Endovascular Surgery, University of California - San Diego, 9434 Medical Center Drive, Mail Code 9403, La Jolla, CA 92037. E-mail address: [email protected] 0065-3411/14/$ – see front matter http://dx.doi.org/10.1016/j.yasu.2014.05.018
Ó 2014 Elsevier Inc. All rights reserved.
2
INUI & BANDYK
when Dubost and colleagues [2] reported of replacement of the aneurysmal aorta using a homograft. For the next 40 years, surgeons adopted the pioneering work of Dr Michael Debakey, performing polyester graft replacement of the aneurysmal aortoiliac segment for both ruptured and nonruptured AAAs [3]. Surgical treatment of AAA changed in 1991 when the feasibility of endovascular repair of an AAA was demonstrated by Parodi and colleagues [4]. This technique was initially used in patients deemed to be at high risk for open surgery, but this recommendation rapidly changed due to the low (1%–2%) observed 30-day mortality and reduced morbidity of endovascular aortic aneurysm repair (EVAR). Since 2000, the application of EVAR for infrarenal AAA repair has been exponential, 290% per year in one retrospective series, and has become the preferred repair technique for both nonruptured and ruptured AAAs [5]. Initially, the EVAR procedure, which involves exclusion of the AAA sac from arterial pressure using a stent graft, was performed via open, bilateral surgical exposure of the common femoral artery to enable device implantation using large French catheter delivery systems. With Food and Drug Administration approval of AAA endografts in 1999, vascular surgeons either working alone or in conjunction with interventional vascular radiologists began performing EVAR in large numbers. By 2005, most vascular surgeons had developed appropriate endovascular skills and experience with EVAR so that greater than 80% of all open and EVAR repairs were performed by this surgical specialty. Medical and vascular surgery specialty consensus papers provided guidance regarding minimal procedural experience necessary for both surgeons and other interventionalists to be deemed competent to perform EVAR [6–10]. In selected institutions, interventional cardiologists or radiologists working with a general or cardiac surgeon also performed EVAR, a trend that has continued to the present, primarily the development of smaller diameter stent-graft delivery systems that can be implanted using percutaneous access and artery puncture closure devices. The application of endovascular therapy for AAAs continues to evolve, with its applicability expanded to a wide range of AAA anatomy including aneurysmal degeneration involving the visceral and hypogastric arteries [11–13]. Expected patient outcomes such as AAA-related mortality must therefore account for differences in AAA anatomy and the use of new endograft stent-graft technology. WHO SHOULD PERFORM EVAR? Comparative effectiveness research is defined by the Institute of Medicine as ‘‘the generation and synthesis of evidence that compares the alternative methods to treat a clinical condition or improve the delivery of care’’. The impact of physician specialty on EVAR outcomes has not been studied in detail. Who cares for the AAA patient and performs EVAR remains a credentialing issue at each institution with the requirement of specific physician’s qualifications (ie, specialty board certification) and experience (resident/fellowship training, number of procedures as the primary operator). Although the clinical
ENDOVASCULAR AORTIC ANEURYSM REPAIR
3
trials evaluating the safety and efficacy of EVAR have conclusively shown that early mortality and perioperative morbidity (transfusion requirement, intensive care unit [ICU], and hospital length-of-stay) are improved following EVAR, who performed the procedure was not queried [14,15]. Whether the EVAR patient benefits or outcomes are related to the physician specialty has not been addressed despite known differences in residency education between vascular surgeons, interventional radiologists, and interventional cardiologists. Specific experience regarding elective and emergent care of the AAA patient also differs between vascular surgeons and interventionists in the areas of AAA caseload, preoperative decision making (open vs endovascular), and patient care after EVAR. Thus, a discussion regarding how EVAR is performed is relevant for patient education of expected outcomes, informed consent, and allocation of an institution’s resources. As health care systems continue to evolve, patient outcomes are linked not only to individual patient characteristics but also to provider and institutional factors and the therapeutics options available. The expansion of percutaneous EVAR (PEVAR) has changed procedural qualifications and allows interventionalists from multiple specialties (vascular surgery, cardiac surgery, radiology, cardiology) with appropriate endotherapy skills and angiographic suite access to execute this procedure. In a minority (10%–20%) of patients, there is advanced atherosclerotic occlusive disease involving the common femoral artery, which precludes a percutaneous approach; for example, a vascular surgery is required to provide access for stent-graft delivery and repair the diseased artery. The specialty of the physician who performs EVAR is one component of patient care, but there are other important considerations, including patient selection criteria, stent-graft–specific information for use (IFU) criteria, management of procedural complications, and post-procedural surveillance for the AAA sac endoleak and device complications. Questions that need to be addressed by all EVAR interventionalists and the health care system that supports them are the following: (1) what institutional requirements are necessary to build a clinical pathway of excellence to care for AAA patient, irrespective of whether or not they are suitable for endovascular repair; (2) how should institution resources, evolving EVAR technology, and techniques be applied in a cost-effective manner; and lastly (3) who should provide care for the EVAR patient during the perioperative period and long-term? Recent comparative effective research has shown that vascular surgeons have decreased mortality, length of stay (LOS), and hospital charges as compared with other interventionists performing EVAR [5]. This retrospective analysis of 28,094 EVAR procedures (ICD-9 code 39.71) was performed using the Nationwide Inpatient Sample from 2001 to 2009. Providers performing EVAR for AAA were considered to be vascular surgeons if they had performed at least one elective case of open AAA repair (ICD-9 38.44) within the year corresponding to their EVAR procedure. To account for the possibility that surgeons just completed training and had not yet done an open repair of AAA, providers were also labeled as vascular surgeons if they had performed a
4
INUI & BANDYK
dialysis access or carotid endarterectomy procedure. EVAR providers were considered ‘‘interventionists’’ if they did not meet these criteria. This study demonstrated that the annual number of EVAR procedures doubled from approximately 2000 to 4000 during the study period, with increases in both vascular surgeon and interventionist volume (Fig. 1). Vascular surgeons performed 92% of the EVAR procedures and had a significantly higher annual volume compared with interventionists (6.4 vs 1.9 procedures; P<.0001). Patients of vascular surgeons tended to be older and have more comorbidities, but the incidence of ruptured AAA treated by EVAR was higher (5.9% vs 2.7%) in the interventionist group. The unadjusted mortality rate was 2% for vascular surgeons and 4.3% for interventionists, P<.001 (Fig. 2). On multivariate analysis after controlling for provider annual EVAR volume, AAA rupture status, presence of hypovolemic shock, hospital teaching status, patient comorbidities, and patient demographic variables, provider specialty was associated with significant variation in mortality, total hospital charges, and LOS. Interventionists were associated with more than a 39% increased likelihood of in-hospital mortality (odds ratio 1.39, P ¼ .027), (see Fig. 2). Interventionists were also associated with an additional $19,312 in hospital charges per admission (P<.001), and an additional 1.32 days in LOS relative to vascular surgeons (P<.001). High provider volume was also associated with significant reductions in mortality, total hospital charges, and LOS relative to low provider volume. It is notable that the effect of provider specialty occurred independent of the volume-outcome relationship. In contrast, hospital teaching status was not associated with outcome differences. These results indicate that vascular surgeons possess an efficacy advantage in performing EVAR, which may be due to differences in training, experience, and caseload. Comparative effectiveness research has demonstrated that both
Fig. 1. EVAR for AAA volume by provider specialty (vascular surgeon, interventionalist) from 2001 to 2009.
ENDOVASCULAR AORTIC ANEURYSM REPAIR
5
Fig. 2. Risk-adjusted mortality rates for interventionalists versus surgeons over time.
physician and hospital case volume are predictors of patient outcome. Within vascular surgery, annual surgeon AAA repair volume and specialty fellowship training are associated with lower 30-day patient morbidity and mortality [16– 18]. The outcome differences between surgeons and interventionists associated with the EVAR may also be related to institutional referral patterns, especially caring for hospitalized patients found to have symptomatic or large AAA, which limits preoperative assessment and procedure planning. Vascular surgeons also have more comprehensive understanding of AAA management due to exposure to open AA repair, which conveys skills that are relevant to addressing EVAR procedural adverse events related to access exposure and delivery of the device via the iliac arteries, especially the need for open conversion. Without in-depth surgical experience, interventionists may not have the same acumen to select patients for EVAR and conduct the procedure. How nonsurgeon interventionists develop the skills and experience to provide care to the AAA needs to be addressed within the framework of their resident training programs. The observed outcome differences have health policy implications regarding selective patient referral for AAA repair and institutional credentialing issues regarding EVAR privileges, including whether a multidisciplinary specialty approach within a cardiovascular center is necessary or desirable. CENTERS OF EXCELLENCE FOR AAA MANAGEMENT AND EVAR The institutions supporting vascular surgeons have a responsibility to the AAA patient for providing appropriate facilities for elective and emergent repair, including EVAR. Achieving the status as a center of excellence in AAA management requires appropriate vascular imaging services, hybrid operating rooms, and patient care pathways that include ICU services, if necessary. After discharge, all patients with AAA repairs, especially an EVAR procedure,
6
INUI & BANDYK
require surveillance to document technical success and predict freedom from AAA rupture. Periodic vascular imaging (ultrasound, computed tomography angiography) is required to confirm AAA sac enlargement or that stent-graft failure has occurred. Ideally, patients at risk for AAA should be identified by their health care system by a primary care physician screening program. Expeditious referral of patients with AAA to vascular surgery clinics ensures prompt evaluation and counseling, desirable components of maintaining disease specific excellence. Because vascular surgeons have been instrumental in developing AAA screening and community outreach programs to identify and educate the AAA patient, it is logical that this specialty performs most open AAA repairs and EVARs. The Society for Vascular Surgery (SVS) recommends that referral to a vascular specialist be made if an ultrasound screening study identifies an AAA of greater than 4.5 cm [19]. The development of AAA screening programs has been demonstrated in multiple Western countries to facilitate the identification of asymptomatic patients who require AAA repair and have anatomy appropriate for EVAR, thereby reducing the frequency of ruptured AAA with its increased mortality and health care costs [20–23]. The US Preventive Services Task Force has endorsed AAA screening and also made specific recommendations for surveillance of small- to intermediate-size (3–5.4 cm) AAAs that have not been shown to have improved outcomes with endovascular repair [24,25]. Aneurysms that do not meet criteria for intervention but that do require surveillance should be followed by serial vascular imaging studies, typically duplex ultrasound. Surveillance should be performed in an accredited vascular laboratory and interpreted by physicians certified in vascular interpretation. Recommendations for provider certification can be found in consensus guidelines published by the Inter-societal Commission for Accreditation of Vascular Laboratories [26]. EVAR SKILLS OF SURGEONS AND INTERVENTIONALISTS Vascular surgeons and interventional radiologists/cardiologists have developed significant overlap in types of the endovascular therapies offered. This overlap occurred by a concerted effort of these physicians to develop resident training programs that provide comprehensive endovascular training in a variety of vascular beds. This approach has allowed the trainees to be exposed to and participate in complex endovascular interventions throughout the circulatory system, including EVAR and endoleak management [8,10]. The skills and experience acquired by an individual specialty resident during training may vary as will their ability to be credentialed. A 2004 consensus statement from the professional societies involved in the vascular care, including SVS, American College of Cardiology, and Society of Interventional Radiology, published recommendations for defining competence in peripheral catheter-based interventions. The EVAR experience guideline was a minimum number of 10 procedures, with 5 procedures as the primary operator, and documentation of core vascular training in AAA
ENDOVASCULAR AORTIC ANEURYSM REPAIR
7
management. This document did not provide specific recommendations for determining interventional radiologists’ competence in performing EVAR as the primary operator because at this time all procedures were performed via open surgical exposure of the common femoral arteries. The consensus statement did acknowledge that physicians providing endovascular therapy should be experienced in diagnostic angiography, catheter-directed thrombolysis, and peripheral angioplasty techniques [27]. The Society of Interventional Radiology agreed in principle with formulating a training curriculum for vascular medicine; they disagreed with the procedural training recommendations, particularly with the recommended procedure numbers in the cerebrovascular interventions [28]. This disagreement did not directly address the management of AAAs by EVAR; however, it did highlight the distinction between interventional radiology as a procedurally based specialty whose training philosophy and recommendations are based more strictly around experiential learning and not that of the more comprehensive training model endorsed by the SVS. The 2008 SVS practice guidelines recommended a minimal number of 20 EVARs as primary operator to be eligible for hospital credentialing, citing the increasing frequency of this option compared with ‘‘open’’ AAA repair. This level of experience may be attained by interventional radiologists at only selected high-volume institutions involved in AAA surgery, but is less likely in a community hospital setting. The focus of obtaining experience placing endografts during training is critical because early familiarization of the physician with this procedure in a structured learning environment, including adherence to device-specific IFUs, is conducive to later practice development and refinement of EVAR skills. In all specialty training environments, the resident has exposure and contact with vascular surgeons who make decisions regarding complex AAA anatomy and suitability of the patient for open repair. Recognizing the evolution of endovascular therapy, the number of AAA repair procedures performed by surgeons will likely decrease. The EVAR comparative effectiveness data suggest there is an advantage for a vascular surgeon to have a primary role in AAA management, including consideration for EVAR. This approach is likely to optimize early patient outcomes—decreased 30-day mortality, LOS, and total hospital charges. The observed average LOS decrease of 1.4 days likely represents a decrease in the perioperative complications that drive both LOS and cost of hospitalization and may be blunted by adoption of PEVAR. Comparative effectiveness research reminds the medical community of the importance of continuous outcome monitoring and evaluation of new procedures because they are adopted by interventionists. IS THERE A ROLE FOR MULTIDISCIPLINARY EVAR CARE? Endovascular stent-graft exclusion of the aneurysm sac has become the preferred technique for AAA repair. Appropriate decision making regarding ‘‘open’’ surgical repair versus EVAR is a critical part of the preoperative workup for patients presenting for both elective and emergent repair. Each
8
INUI & BANDYK
device has specific IFU criteria confirmed in clinical trials to minimize the likelihood of endoleak and AAA-related mortality. The likelihood of continued AAA sac enlargement after EVAR correlates with the presence of endoleak and compliance with endograft IFU criteria. Schanzer and colleagues [29] reported results from 10,228 patients undergoing EVAR that demonstrated only 42% of patients had anatomy that met the most conservative definition of device IFU, whereas 31% were outside the most liberal definition of device instructions for use. The 5-year post-EVAR rate of AAA sac enlargement was 41%. Independent predictors of AAA sac enlargement included endoleak, age greater than 80 years, aortic neck diameter greater than 28 mm, aortic neck angle greater than 60 , and common iliac artery diameter greater than 20 mm. Patients with a type I endoleak after EVAR do not receive any decreased risk in mortality, and thus identifying those patients whose anatomy is ill-suited to EVAR is important before embarking on endograft repair [30]. This is particularly true for those patients for whom their age and other comorbidities would not preclude them from being an appropriate endovascular candidate. It is critically important that interventionists performing EVAR develop a close working relationship with a vascular surgeon regarding suitability for EVAR and for the management of anticipated events associated with device usage outside the IFU and potential access complications caused by arterial occlusive disease. Anecdotal description of highly functioning interdisciplinary teams have shown excellent outcomes for the patients cared for by these teams, as would be expected [31]. Close follow-up within a vascular group would intuitively lead to better care of patients especially those with complex AAA anatomy, who may need multiple post-EVAR imaging studies and/or procedures. Finally, it is important to note that patients whose anatomy is better suited to open AAA repair should be referred to experienced vascular surgeons, as the provider volume-outcome relationship has been shown to be important for the repair of open AAA as well [32,33]. In summary, the optimal management of patients with AAA by EVAR requires multiple levels of resources. Patients need a well-delineated referral system for prompt imaging and evaluation of their AAA. Those patients who have aneurysms too small to require repair should have ultrasound surveillance every 6 month by a certified vascular laboratory with accredited technologists and physician interpreters. Patients found to have appropriate anatomy for EVAR may benefit from an integrated, multidisciplinary team led by vascular surgeons that can assist in the device-related decision making for each patient, as well as address any additional needed procedures during early postoperative EVAR period. References [1] Endovascular repair of abdominal aortic aneurysm: an evidence-based analysis. Ont Health Technol Assess Ser 2002;2(1):1–46. [2] Dubost C, Allary M, Oeconomos N. Resection of an aneurysm of the abdominal aorta: reestablishment of the continuity by a preserved human arterial graft, with result after five months. AMA Arch Surg 1952;64(3):405–8.
ENDOVASCULAR AORTIC ANEURYSM REPAIR
9
[3] DeBakey ME, Cooley DA, Crawford ES, et al. Clinical application of a new flexible knitted Dacron arterial substitute. 1958. Am Surg 2008;74(5):381–6. [4] Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;5(6):491–9. [5] McCutcheon BA, Talamini MA, Chang DC, et al. The comparative effectiveness of surgeons over interventionalists in endovascular repairs of abdominal aortic aneurysm. Ann Surg 2013;258(3):476–82. [6] Guidelines for percutaneous transluminal angioplasty. Standards of Practice Committee of the Society of Cardiovascular and Interventional Radiology. Radiology 1990;177(3): 619–26. [7] Spittell JA Jr, Creager MA, Dorros G, et al. Recommendations for peripheral transluminal angioplasty: training and facilities. American College of Cardiology Peripheral Vascular Disease Committee. J Am Coll Cardiol 1993;21(2):546–8. [8] White RA, Hodgson KJ, Ahn SS, et al. Endovascular interventions training and credentialing for vascular surgeons. J Vasc Surg 1999;29(1):177–86. [9] Kashyap VS, Ahn SS, Petrik PV, et al. Current training and practice of endovascular surgery: a survey. Ann Vasc Surg 2001;15(3):294–305. [10] Weaver FA, Hood DB, Shah H, et al. Current guidelines produce competent endovascular surgeons. J Vasc Surg 2006;43(5):992–8 [discussion: 998]. [11] Greenberg RK, West K, Pfaff K, et al. Beyond the aortic bifurcation: branched endovascular grafts for thoracoabdominal and aortoiliac aneurysms. J Vasc Surg 2006;43(5):879–86 [discussion: 886–7]. [12] Verhoeven EL, Vourliotakis G, Bos WT, et al. Fenestrated stent grafting for short-necked and juxtarenal abdominal aortic aneurysm: an 8-year single-centre experience. Eur J Vasc Endovasc Surg 2010;39(5):529–36. [13] Bruen KJ, Feezor RJ, Daniels MJ, et al. Endovascular chimney technique versus open repair of juxtarenal and suprarenal aneurysms. J Vasc Surg 2011;53(4):895–904 [discussion: 904–5]. [14] Greenhalgh RM, Brown LC, Kwong GP, et al. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 2004;364(9437):843–8. [15] Lederle FA, Freischlag JA, Kyriakides TC, et al. Outcomes following endovascular vs open repair of abdominal aortic aneurysm: a randomized trial. JAMA 2009;302(14):1535–42. [16] McPhee JT, Robinson WP 3rd, Eslami MH, et al. Surgeon case volume, not institution case volume, is the primary determinant of in-hospital mortality after elective open abdominal aortic aneurysm repair. J Vasc Surg 2011;53(3):591–9.e2. [17] Karthikesalingam A, Hinchliffe RJ, Loftus IM, et al. Volume-outcome relationships in vascular surgery: the current status. J Endovasc Ther 2010;17(3):356–65. [18] Dimick JB, Upchurch GR Jr. Endovascular technology, hospital volume, and mortality with abdominal aortic aneurysm surgery. J Vasc Surg 2008;47(6):1150–4. [19] Chaikof EL, Brewster DC, Dalman RL, et al. The care of patients with an abdominal aortic aneurysm: the Society for Vascular Surgery practice guidelines. J Vasc Surg 2009;50(Suppl 4):S2–49. [20] Fleming C, Whitlock EP, Beil T, et al. Primary Care Screening for Abdominal Aortic Aneurysm. Evidence Synthesis No. 35 (Prepared by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024.) Rockville, MD: Agency for Healthcare Research and Quality; February 2005. Available on the AHRQ Website at: http://www.uspreventive servicestaskforce.org/serfiles.htm. Accessed June 16, 2014. [21] Fleming C, Whitlock EP, Beil T, et al. Screening for abdominal aortic aneurysm: a bestevidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med 2005;142(3):203–11. [22] Kim LG, P Scott RA, Ashton HA, et al. A sustained mortality benefit from screening for abdominal aortic aneurysm. Ann Intern Med 2007;146(10):699–706.
10
INUI & BANDYK
[23] Dabare D, Lo TT, McCormack DJ, et al. What is the role of screening in the management of abdominal aortic aneurysms? Interact Cardiovasc Thorac Surg 2012;14(4):399–405. [24] Ouriel K, Clair DG, Kent KC, et al. Endovascular repair compared with surveillance for patients with small abdominal aortic aneurysms. J Vasc Surg 2010;51(5):1081–7. [25] Cao P, De Rango P, Verzini F, et al. Comparison of surveillance versus aortic endografting for small aneurysm repair (CAESAR): results from a randomised trial. Eur J Vasc Endovasc Surg 2011;41(1):13–25. [26] IAC standards and guidelines for vascular testing accreditation 2013. Available at: http:// intersocietal.org/vascular/standards/IACVascularTestingStandards2013.pdf. Accessed June 17, 2014. [27] Creager MA, Goldstone J, Hirshfeld JW Jr, et al. ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on vascular medicine and catheter-based peripheral vascular interventions. A report of the American College of Cardiology/American Heart Association/ American College of Physicians Task Force on Clinical Competence (ACC/ACP/SCAI/ SVMB/SVS Writing Committee to develop a clinical competence statement on peripheral vascular disease). Vasc Med 2004;9(3):233–48. [28] Sacks D. Response to the ACC/ACP/SCAI/SVMB/SVS clinical competence statement on catheter-based peripheral vascular interventions. J Vasc Interv Radiol 2005;16(1):1–4. [29] Schanzer A, Greenberg RK, Hevelone N, et al. Predictors of abdominal aortic aneurysm sac enlargement after endovascular repair. Circulation 2011;123:2848–55. [30] May J, White GH, Stephen MS, et al. Rupture of abdominal aortic aneurysm: concurrent comparison of outcome of those occurring after endovascular repair versus those occurring without previous treatment in an 11-year single-center experience. J Vasc Surg 2004;40(5): 860–6. [31] McIff EB, Smilanich RP, McIff D. A community hospital approach to establishing a successful EVAR program. Endovascular Today 2006;8. [32] Modrall JG, Rosero EB, Chung J, et al. Defining the type of surgeon volume that influences the outcomes for open abdominal aortic aneurysm repair. J Vasc Surg 2011;54(6): 1599–604. [33] Kresowik TF. Invited commentary. J Vasc Surg 2011;54(6):1604.
ADVANCES IN SURGERY Can Interventionalists do Endovascular Aortic Aneurysm Repair As Well As Vascular Surgeons? Tazo Inui, MD, Dennis F. Bandyk, MD* Division of Vascular & Endovascular Surgery, Sulpizio Cardiovascular Center, University of California - San Diego School of Medicine, 9434 Medical Center Drive, La Jolla, CA 92037, USA
Keywords
Abdominal aortic aneurysm Endovascular aneurysm repair Vascular surgery Interventional radiology System utilization Multispecialty team
Key points
Most of the abdominal aortic aneurysms are currently repaired using an endovascular stent graft implanted via a femoral artery approach, often via percutaneous access.
Vascular surgeons and interventional radiologists/cardiologists are performing endovascular aortic aneurysm repairs (EVARs) in large numbers.
Comparative effectiveness research suggests EVAR performed by vascular surgeons is associated with lower mortality, shorter length of stay, and lower costs compared with the repair performed by interventional radiologists or cardiologists.
Interventionists who perform EVAR may optimize their care by working with a vascular surgeon as a multidisciplinary team, thereby using all of an institution’s resources.
BACKGROUND Abdominal aortic aneurysm (AAA) is a focal degeneration of the aorta present in 1% to 5% of the population, with rupture being the most common complication resulting in approximately 15,000 deaths per annum in the United States [1]. Screening for AAA is now recommended in selected high-risk populations: men older than 65 years, men and women who have smoked tobacco, or individuals with a family history of AAA. The era of AAA repair began in 1952 *Corresponding author. Division of Vascular & Endovascular Surgery, University of California - San Diego, 9434 Medical Center Drive, Mail Code 9403, La Jolla, CA 92037. E-mail address: [email protected] 0065-3411/14/$ – see front matter http://dx.doi.org/10.1016/j.yasu.2014.05.018
Ó 2014 Elsevier Inc. All rights reserved.
2
INUI & BANDYK
when Dubost and colleagues [2] reported of replacement of the aneurysmal aorta using a homograft. For the next 40 years, surgeons adopted the pioneering work of Dr Michael Debakey, performing polyester graft replacement of the aneurysmal aortoiliac segment for both ruptured and nonruptured AAAs [3]. Surgical treatment of AAA changed in 1991 when the feasibility of endovascular repair of an AAA was demonstrated by Parodi and colleagues [4]. This technique was initially used in patients deemed to be at high risk for open surgery, but this recommendation rapidly changed due to the low (1%–2%) observed 30-day mortality and reduced morbidity of endovascular aortic aneurysm repair (EVAR). Since 2000, the application of EVAR for infrarenal AAA repair has been exponential, 290% per year in one retrospective series, and has become the preferred repair technique for both nonruptured and ruptured AAAs [5]. Initially, the EVAR procedure, which involves exclusion of the AAA sac from arterial pressure using a stent graft, was performed via open, bilateral surgical exposure of the common femoral artery to enable device implantation using large French catheter delivery systems. With Food and Drug Administration approval of AAA endografts in 1999, vascular surgeons either working alone or in conjunction with interventional vascular radiologists began performing EVAR in large numbers. By 2005, most vascular surgeons had developed appropriate endovascular skills and experience with EVAR so that greater than 80% of all open and EVAR repairs were performed by this surgical specialty. Medical and vascular surgery specialty consensus papers provided guidance regarding minimal procedural experience necessary for both surgeons and other interventionalists to be deemed competent to perform EVAR [6–10]. In selected institutions, interventional cardiologists or radiologists working with a general or cardiac surgeon also performed EVAR, a trend that has continued to the present, primarily the development of smaller diameter stent-graft delivery systems that can be implanted using percutaneous access and artery puncture closure devices. The application of endovascular therapy for AAAs continues to evolve, with its applicability expanded to a wide range of AAA anatomy including aneurysmal degeneration involving the visceral and hypogastric arteries [11–13]. Expected patient outcomes such as AAA-related mortality must therefore account for differences in AAA anatomy and the use of new endograft stent-graft technology. WHO SHOULD PERFORM EVAR? Comparative effectiveness research is defined by the Institute of Medicine as ‘‘the generation and synthesis of evidence that compares the alternative methods to treat a clinical condition or improve the delivery of care’’. The impact of physician specialty on EVAR outcomes has not been studied in detail. Who cares for the AAA patient and performs EVAR remains a credentialing issue at each institution with the requirement of specific physician’s qualifications (ie, specialty board certification) and experience (resident/fellowship training, number of procedures as the primary operator). Although the clinical
ENDOVASCULAR AORTIC ANEURYSM REPAIR
3
trials evaluating the safety and efficacy of EVAR have conclusively shown that early mortality and perioperative morbidity (transfusion requirement, intensive care unit [ICU], and hospital length-of-stay) are improved following EVAR, who performed the procedure was not queried [14,15]. Whether the EVAR patient benefits or outcomes are related to the physician specialty has not been addressed despite known differences in residency education between vascular surgeons, interventional radiologists, and interventional cardiologists. Specific experience regarding elective and emergent care of the AAA patient also differs between vascular surgeons and interventionists in the areas of AAA caseload, preoperative decision making (open vs endovascular), and patient care after EVAR. Thus, a discussion regarding how EVAR is performed is relevant for patient education of expected outcomes, informed consent, and allocation of an institution’s resources. As health care systems continue to evolve, patient outcomes are linked not only to individual patient characteristics but also to provider and institutional factors and the therapeutics options available. The expansion of percutaneous EVAR (PEVAR) has changed procedural qualifications and allows interventionalists from multiple specialties (vascular surgery, cardiac surgery, radiology, cardiology) with appropriate endotherapy skills and angiographic suite access to execute this procedure. In a minority (10%–20%) of patients, there is advanced atherosclerotic occlusive disease involving the common femoral artery, which precludes a percutaneous approach; for example, a vascular surgery is required to provide access for stent-graft delivery and repair the diseased artery. The specialty of the physician who performs EVAR is one component of patient care, but there are other important considerations, including patient selection criteria, stent-graft–specific information for use (IFU) criteria, management of procedural complications, and post-procedural surveillance for the AAA sac endoleak and device complications. Questions that need to be addressed by all EVAR interventionalists and the health care system that supports them are the following: (1) what institutional requirements are necessary to build a clinical pathway of excellence to care for AAA patient, irrespective of whether or not they are suitable for endovascular repair; (2) how should institution resources, evolving EVAR technology, and techniques be applied in a cost-effective manner; and lastly (3) who should provide care for the EVAR patient during the perioperative period and long-term? Recent comparative effective research has shown that vascular surgeons have decreased mortality, length of stay (LOS), and hospital charges as compared with other interventionists performing EVAR [5]. This retrospective analysis of 28,094 EVAR procedures (ICD-9 code 39.71) was performed using the Nationwide Inpatient Sample from 2001 to 2009. Providers performing EVAR for AAA were considered to be vascular surgeons if they had performed at least one elective case of open AAA repair (ICD-9 38.44) within the year corresponding to their EVAR procedure. To account for the possibility that surgeons just completed training and had not yet done an open repair of AAA, providers were also labeled as vascular surgeons if they had performed a
4
INUI & BANDYK
dialysis access or carotid endarterectomy procedure. EVAR providers were considered ‘‘interventionists’’ if they did not meet these criteria. This study demonstrated that the annual number of EVAR procedures doubled from approximately 2000 to 4000 during the study period, with increases in both vascular surgeon and interventionist volume (Fig. 1). Vascular surgeons performed 92% of the EVAR procedures and had a significantly higher annual volume compared with interventionists (6.4 vs 1.9 procedures; P<.0001). Patients of vascular surgeons tended to be older and have more comorbidities, but the incidence of ruptured AAA treated by EVAR was higher (5.9% vs 2.7%) in the interventionist group. The unadjusted mortality rate was 2% for vascular surgeons and 4.3% for interventionists, P<.001 (Fig. 2). On multivariate analysis after controlling for provider annual EVAR volume, AAA rupture status, presence of hypovolemic shock, hospital teaching status, patient comorbidities, and patient demographic variables, provider specialty was associated with significant variation in mortality, total hospital charges, and LOS. Interventionists were associated with more than a 39% increased likelihood of in-hospital mortality (odds ratio 1.39, P ¼ .027), (see Fig. 2). Interventionists were also associated with an additional $19,312 in hospital charges per admission (P<.001), and an additional 1.32 days in LOS relative to vascular surgeons (P<.001). High provider volume was also associated with significant reductions in mortality, total hospital charges, and LOS relative to low provider volume. It is notable that the effect of provider specialty occurred independent of the volume-outcome relationship. In contrast, hospital teaching status was not associated with outcome differences. These results indicate that vascular surgeons possess an efficacy advantage in performing EVAR, which may be due to differences in training, experience, and caseload. Comparative effectiveness research has demonstrated that both
Fig. 1. EVAR for AAA volume by provider specialty (vascular surgeon, interventionalist) from 2001 to 2009.
ENDOVASCULAR AORTIC ANEURYSM REPAIR
5
Fig. 2. Risk-adjusted mortality rates for interventionalists versus surgeons over time.
physician and hospital case volume are predictors of patient outcome. Within vascular surgery, annual surgeon AAA repair volume and specialty fellowship training are associated with lower 30-day patient morbidity and mortality [16– 18]. The outcome differences between surgeons and interventionists associated with the EVAR may also be related to institutional referral patterns, especially caring for hospitalized patients found to have symptomatic or large AAA, which limits preoperative assessment and procedure planning. Vascular surgeons also have more comprehensive understanding of AAA management due to exposure to open AA repair, which conveys skills that are relevant to addressing EVAR procedural adverse events related to access exposure and delivery of the device via the iliac arteries, especially the need for open conversion. Without in-depth surgical experience, interventionists may not have the same acumen to select patients for EVAR and conduct the procedure. How nonsurgeon interventionists develop the skills and experience to provide care to the AAA needs to be addressed within the framework of their resident training programs. The observed outcome differences have health policy implications regarding selective patient referral for AAA repair and institutional credentialing issues regarding EVAR privileges, including whether a multidisciplinary specialty approach within a cardiovascular center is necessary or desirable. CENTERS OF EXCELLENCE FOR AAA MANAGEMENT AND EVAR The institutions supporting vascular surgeons have a responsibility to the AAA patient for providing appropriate facilities for elective and emergent repair, including EVAR. Achieving the status as a center of excellence in AAA management requires appropriate vascular imaging services, hybrid operating rooms, and patient care pathways that include ICU services, if necessary. After discharge, all patients with AAA repairs, especially an EVAR procedure,
6
INUI & BANDYK
require surveillance to document technical success and predict freedom from AAA rupture. Periodic vascular imaging (ultrasound, computed tomography angiography) is required to confirm AAA sac enlargement or that stent-graft failure has occurred. Ideally, patients at risk for AAA should be identified by their health care system by a primary care physician screening program. Expeditious referral of patients with AAA to vascular surgery clinics ensures prompt evaluation and counseling, desirable components of maintaining disease specific excellence. Because vascular surgeons have been instrumental in developing AAA screening and community outreach programs to identify and educate the AAA patient, it is logical that this specialty performs most open AAA repairs and EVARs. The Society for Vascular Surgery (SVS) recommends that referral to a vascular specialist be made if an ultrasound screening study identifies an AAA of greater than 4.5 cm [19]. The development of AAA screening programs has been demonstrated in multiple Western countries to facilitate the identification of asymptomatic patients who require AAA repair and have anatomy appropriate for EVAR, thereby reducing the frequency of ruptured AAA with its increased mortality and health care costs [20–23]. The US Preventive Services Task Force has endorsed AAA screening and also made specific recommendations for surveillance of small- to intermediate-size (3–5.4 cm) AAAs that have not been shown to have improved outcomes with endovascular repair [24,25]. Aneurysms that do not meet criteria for intervention but that do require surveillance should be followed by serial vascular imaging studies, typically duplex ultrasound. Surveillance should be performed in an accredited vascular laboratory and interpreted by physicians certified in vascular interpretation. Recommendations for provider certification can be found in consensus guidelines published by the Inter-societal Commission for Accreditation of Vascular Laboratories [26]. EVAR SKILLS OF SURGEONS AND INTERVENTIONALISTS Vascular surgeons and interventional radiologists/cardiologists have developed significant overlap in types of the endovascular therapies offered. This overlap occurred by a concerted effort of these physicians to develop resident training programs that provide comprehensive endovascular training in a variety of vascular beds. This approach has allowed the trainees to be exposed to and participate in complex endovascular interventions throughout the circulatory system, including EVAR and endoleak management [8,10]. The skills and experience acquired by an individual specialty resident during training may vary as will their ability to be credentialed. A 2004 consensus statement from the professional societies involved in the vascular care, including SVS, American College of Cardiology, and Society of Interventional Radiology, published recommendations for defining competence in peripheral catheter-based interventions. The EVAR experience guideline was a minimum number of 10 procedures, with 5 procedures as the primary operator, and documentation of core vascular training in AAA
ENDOVASCULAR AORTIC ANEURYSM REPAIR
7
management. This document did not provide specific recommendations for determining interventional radiologists’ competence in performing EVAR as the primary operator because at this time all procedures were performed via open surgical exposure of the common femoral arteries. The consensus statement did acknowledge that physicians providing endovascular therapy should be experienced in diagnostic angiography, catheter-directed thrombolysis, and peripheral angioplasty techniques [27]. The Society of Interventional Radiology agreed in principle with formulating a training curriculum for vascular medicine; they disagreed with the procedural training recommendations, particularly with the recommended procedure numbers in the cerebrovascular interventions [28]. This disagreement did not directly address the management of AAAs by EVAR; however, it did highlight the distinction between interventional radiology as a procedurally based specialty whose training philosophy and recommendations are based more strictly around experiential learning and not that of the more comprehensive training model endorsed by the SVS. The 2008 SVS practice guidelines recommended a minimal number of 20 EVARs as primary operator to be eligible for hospital credentialing, citing the increasing frequency of this option compared with ‘‘open’’ AAA repair. This level of experience may be attained by interventional radiologists at only selected high-volume institutions involved in AAA surgery, but is less likely in a community hospital setting. The focus of obtaining experience placing endografts during training is critical because early familiarization of the physician with this procedure in a structured learning environment, including adherence to device-specific IFUs, is conducive to later practice development and refinement of EVAR skills. In all specialty training environments, the resident has exposure and contact with vascular surgeons who make decisions regarding complex AAA anatomy and suitability of the patient for open repair. Recognizing the evolution of endovascular therapy, the number of AAA repair procedures performed by surgeons will likely decrease. The EVAR comparative effectiveness data suggest there is an advantage for a vascular surgeon to have a primary role in AAA management, including consideration for EVAR. This approach is likely to optimize early patient outcomes—decreased 30-day mortality, LOS, and total hospital charges. The observed average LOS decrease of 1.4 days likely represents a decrease in the perioperative complications that drive both LOS and cost of hospitalization and may be blunted by adoption of PEVAR. Comparative effectiveness research reminds the medical community of the importance of continuous outcome monitoring and evaluation of new procedures because they are adopted by interventionists. IS THERE A ROLE FOR MULTIDISCIPLINARY EVAR CARE? Endovascular stent-graft exclusion of the aneurysm sac has become the preferred technique for AAA repair. Appropriate decision making regarding ‘‘open’’ surgical repair versus EVAR is a critical part of the preoperative workup for patients presenting for both elective and emergent repair. Each
8
INUI & BANDYK
device has specific IFU criteria confirmed in clinical trials to minimize the likelihood of endoleak and AAA-related mortality. The likelihood of continued AAA sac enlargement after EVAR correlates with the presence of endoleak and compliance with endograft IFU criteria. Schanzer and colleagues [29] reported results from 10,228 patients undergoing EVAR that demonstrated only 42% of patients had anatomy that met the most conservative definition of device IFU, whereas 31% were outside the most liberal definition of device instructions for use. The 5-year post-EVAR rate of AAA sac enlargement was 41%. Independent predictors of AAA sac enlargement included endoleak, age greater than 80 years, aortic neck diameter greater than 28 mm, aortic neck angle greater than 60 , and common iliac artery diameter greater than 20 mm. Patients with a type I endoleak after EVAR do not receive any decreased risk in mortality, and thus identifying those patients whose anatomy is ill-suited to EVAR is important before embarking on endograft repair [30]. This is particularly true for those patients for whom their age and other comorbidities would not preclude them from being an appropriate endovascular candidate. It is critically important that interventionists performing EVAR develop a close working relationship with a vascular surgeon regarding suitability for EVAR and for the management of anticipated events associated with device usage outside the IFU and potential access complications caused by arterial occlusive disease. Anecdotal description of highly functioning interdisciplinary teams have shown excellent outcomes for the patients cared for by these teams, as would be expected [31]. Close follow-up within a vascular group would intuitively lead to better care of patients especially those with complex AAA anatomy, who may need multiple post-EVAR imaging studies and/or procedures. Finally, it is important to note that patients whose anatomy is better suited to open AAA repair should be referred to experienced vascular surgeons, as the provider volume-outcome relationship has been shown to be important for the repair of open AAA as well [32,33]. In summary, the optimal management of patients with AAA by EVAR requires multiple levels of resources. Patients need a well-delineated referral system for prompt imaging and evaluation of their AAA. Those patients who have aneurysms too small to require repair should have ultrasound surveillance every 6 month by a certified vascular laboratory with accredited technologists and physician interpreters. Patients found to have appropriate anatomy for EVAR may benefit from an integrated, multidisciplinary team led by vascular surgeons that can assist in the device-related decision making for each patient, as well as address any additional needed procedures during early postoperative EVAR period. References [1] Endovascular repair of abdominal aortic aneurysm: an evidence-based analysis. Ont Health Technol Assess Ser 2002;2(1):1–46. [2] Dubost C, Allary M, Oeconomos N. Resection of an aneurysm of the abdominal aorta: reestablishment of the continuity by a preserved human arterial graft, with result after five months. AMA Arch Surg 1952;64(3):405–8.
ENDOVASCULAR AORTIC ANEURYSM REPAIR
9
[3] DeBakey ME, Cooley DA, Crawford ES, et al. Clinical application of a new flexible knitted Dacron arterial substitute. 1958. Am Surg 2008;74(5):381–6. [4] Parodi JC, Palmaz JC, Barone HD. Transfemoral intraluminal graft implantation for abdominal aortic aneurysms. Ann Vasc Surg 1991;5(6):491–9. [5] McCutcheon BA, Talamini MA, Chang DC, et al. The comparative effectiveness of surgeons over interventionalists in endovascular repairs of abdominal aortic aneurysm. Ann Surg 2013;258(3):476–82. [6] Guidelines for percutaneous transluminal angioplasty. Standards of Practice Committee of the Society of Cardiovascular and Interventional Radiology. Radiology 1990;177(3): 619–26. [7] Spittell JA Jr, Creager MA, Dorros G, et al. Recommendations for peripheral transluminal angioplasty: training and facilities. American College of Cardiology Peripheral Vascular Disease Committee. J Am Coll Cardiol 1993;21(2):546–8. [8] White RA, Hodgson KJ, Ahn SS, et al. Endovascular interventions training and credentialing for vascular surgeons. J Vasc Surg 1999;29(1):177–86. [9] Kashyap VS, Ahn SS, Petrik PV, et al. Current training and practice of endovascular surgery: a survey. Ann Vasc Surg 2001;15(3):294–305. [10] Weaver FA, Hood DB, Shah H, et al. Current guidelines produce competent endovascular surgeons. J Vasc Surg 2006;43(5):992–8 [discussion: 998]. [11] Greenberg RK, West K, Pfaff K, et al. Beyond the aortic bifurcation: branched endovascular grafts for thoracoabdominal and aortoiliac aneurysms. J Vasc Surg 2006;43(5):879–86 [discussion: 886–7]. [12] Verhoeven EL, Vourliotakis G, Bos WT, et al. Fenestrated stent grafting for short-necked and juxtarenal abdominal aortic aneurysm: an 8-year single-centre experience. Eur J Vasc Endovasc Surg 2010;39(5):529–36. [13] Bruen KJ, Feezor RJ, Daniels MJ, et al. Endovascular chimney technique versus open repair of juxtarenal and suprarenal aneurysms. J Vasc Surg 2011;53(4):895–904 [discussion: 904–5]. [14] Greenhalgh RM, Brown LC, Kwong GP, et al. Comparison of endovascular aneurysm repair with open repair in patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortality results: randomised controlled trial. Lancet 2004;364(9437):843–8. [15] Lederle FA, Freischlag JA, Kyriakides TC, et al. Outcomes following endovascular vs open repair of abdominal aortic aneurysm: a randomized trial. JAMA 2009;302(14):1535–42. [16] McPhee JT, Robinson WP 3rd, Eslami MH, et al. Surgeon case volume, not institution case volume, is the primary determinant of in-hospital mortality after elective open abdominal aortic aneurysm repair. J Vasc Surg 2011;53(3):591–9.e2. [17] Karthikesalingam A, Hinchliffe RJ, Loftus IM, et al. Volume-outcome relationships in vascular surgery: the current status. J Endovasc Ther 2010;17(3):356–65. [18] Dimick JB, Upchurch GR Jr. Endovascular technology, hospital volume, and mortality with abdominal aortic aneurysm surgery. J Vasc Surg 2008;47(6):1150–4. [19] Chaikof EL, Brewster DC, Dalman RL, et al. The care of patients with an abdominal aortic aneurysm: the Society for Vascular Surgery practice guidelines. J Vasc Surg 2009;50(Suppl 4):S2–49. [20] Fleming C, Whitlock EP, Beil T, et al. Primary Care Screening for Abdominal Aortic Aneurysm. Evidence Synthesis No. 35 (Prepared by the Oregon Evidence-based Practice Center under Contract No. 290-02-0024.) Rockville, MD: Agency for Healthcare Research and Quality; February 2005. Available on the AHRQ Website at: http://www.uspreventive servicestaskforce.org/serfiles.htm. Accessed June 16, 2014. [21] Fleming C, Whitlock EP, Beil T, et al. Screening for abdominal aortic aneurysm: a bestevidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med 2005;142(3):203–11. [22] Kim LG, P Scott RA, Ashton HA, et al. A sustained mortality benefit from screening for abdominal aortic aneurysm. Ann Intern Med 2007;146(10):699–706.
10
INUI & BANDYK
[23] Dabare D, Lo TT, McCormack DJ, et al. What is the role of screening in the management of abdominal aortic aneurysms? Interact Cardiovasc Thorac Surg 2012;14(4):399–405. [24] Ouriel K, Clair DG, Kent KC, et al. Endovascular repair compared with surveillance for patients with small abdominal aortic aneurysms. J Vasc Surg 2010;51(5):1081–7. [25] Cao P, De Rango P, Verzini F, et al. Comparison of surveillance versus aortic endografting for small aneurysm repair (CAESAR): results from a randomised trial. Eur J Vasc Endovasc Surg 2011;41(1):13–25. [26] IAC standards and guidelines for vascular testing accreditation 2013. Available at: http:// intersocietal.org/vascular/standards/IACVascularTestingStandards2013.pdf. Accessed June 17, 2014. [27] Creager MA, Goldstone J, Hirshfeld JW Jr, et al. ACC/ACP/SCAI/SVMB/SVS Clinical Competence Statement on vascular medicine and catheter-based peripheral vascular interventions. A report of the American College of Cardiology/American Heart Association/ American College of Physicians Task Force on Clinical Competence (ACC/ACP/SCAI/ SVMB/SVS Writing Committee to develop a clinical competence statement on peripheral vascular disease). Vasc Med 2004;9(3):233–48. [28] Sacks D. Response to the ACC/ACP/SCAI/SVMB/SVS clinical competence statement on catheter-based peripheral vascular interventions. J Vasc Interv Radiol 2005;16(1):1–4. [29] Schanzer A, Greenberg RK, Hevelone N, et al. Predictors of abdominal aortic aneurysm sac enlargement after endovascular repair. Circulation 2011;123:2848–55. [30] May J, White GH, Stephen MS, et al. Rupture of abdominal aortic aneurysm: concurrent comparison of outcome of those occurring after endovascular repair versus those occurring without previous treatment in an 11-year single-center experience. J Vasc Surg 2004;40(5): 860–6. [31] McIff EB, Smilanich RP, McIff D. A community hospital approach to establishing a successful EVAR program. Endovascular Today 2006;8. [32] Modrall JG, Rosero EB, Chung J, et al. Defining the type of surgeon volume that influences the outcomes for open abdominal aortic aneurysm repair. J Vasc Surg 2011;54(6): 1599–604. [33] Kresowik TF. Invited commentary. J Vasc Surg 2011;54(6):1604.