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The Good, the Bad, and the About-to-Get Ugly: National Trends in Carotid Revascularization: Comment on “Geographic Variation in Carotid Revascularization Among Medicare Beneficiaries, 2003-2006”

The Good, the Bad, and the About-to-Get Ugly: National Trends in Carotid Revascularization:... The history of carotid endarterectomy (CEA) is a fascinating good news, bad news story. Wide geographic variations in the use of CEA have been noted for 3 decades, though its popularity has been cyclical. The use of CEA doubled in the early 1980s, but then dropped in half following reports of frequent complications1 and a national Medicare study reporting that one-third of CEAs were inappropriate.2 Subsequently, multinational randomized controlled trials (RCTs) found that, among carefully selected patients and surgeons, CEA reduced the risk of stroke and death compared with medical therapy. Symptomatic patients (with recent carotid stroke or transient ischemic attack), showed great benefit (absolute risk reduction in stroke of 8% per year) over 2 to 3 years.3 Asymptomatic patients had more modest benefit (absolute risk reduction of 1% per year) over 5 years.4,5 Good news followed these rare RCTs of surgery. Practice followed evidence and CEA use doubled.1 A population-based Medicare study also found dramatic declines in CEA for “inappropriate” and “uncertain” indications (32% to 9% and 32% to 4%, respectively), and non-RCT indications (70%-6%).6 The bad news was that despite the dramatic drop in overuse, nearly 1 in 11 CEAs were still deemed inappropriate, mostly in asymptomatic patients with high comorbidity.6 Paradoxically, there is also evidence that it is both underused and overused in minorities.7,8 There has also been “mission creep.” Carotid endarterectomy started out as revascularization for symptomatic patients, though now 70% to 80% of cases are for asymptomatic disease.6 Carotid angioplasty and stenting (CAS), the less-invasive but less well-proven endovascular alternative, is controversial. First-generation RCTs of CEA vs CAS in high-surgical-risk patients yielded mixed results about equivalence and raised concerns because short-term complications were high in both arms, and there was no data on long-term efficacy.9 In October 2004, Medicare restricted reimbursement for CAS to qualified health care providers in high-surgical-risk, symptomatic patients or those enrolled in RCTs or postmarketing studies. In this issue, the article by Patel et al represents an intriguing mix of more good and bad news. They examined Medicare claims from 2003 to 2006 to assess trends in CEA and CAS use by geographical hospital referral region (HRR) among patients 65 years or older. They found that CEA use fell 19%, and despite the Medicare restrictions, CAS increased 33%. Overall carotid vascularization rates dropped 6%. The bad news was that 10 to 15 years after publication of multiple RCTs and national guidelines, there was still 7- to 9-fold differences in age-adjusted CEAs rates across HRRs. There were also wide variations for CAS, perhaps less than CEA, but this is somewhat uncertain because 15% of HRRs had too few CAS cases to calculate stable rates. There was no correlation between use of CEA and CAS by region. A corroborating study of geographic variations in CEA and CAS in Medicare patients was recently published. Goodney et al10 used somewhat different methods but examined trends over a longer period. From 1998 to 2007, use of CEA declined 31% and CAS grew 4-fold, with a small net drop in carotid procedures.10 They also reported 10-fold variations in age, sex, and race-adjusted rates of CEA by HRR that were steady over time, 6-fold variations in CAS, and no correlation between regional rates of CEA and CAS. They and others also found ecological evidence that growth in CAS largely came at the expense of CEA.10,11 Patel et al acknowledge some key limitations of their study. More importantly, utilization studies do not shed light on “which rate is right” because they lack clinical information on symptom status, degree of carotid stenosis, and comorbidity needed to classify the indication for and appropriateness of revascularization. Since many hospitals and physicians perform these procedures within a given HRR, it would be more informative to see rates of overall use (and ideally overuse) analyzed at the hospital, specialty, and physician level. Critically left unmeasured are variations in underuse of carotid revascularization by HRR and health care provider, something not ascertainable via utilization data. What explains these variations? Conceptually, several patient, health care provider, and system factors could contribute via “supply” and “demand” dynamics. While most clinically detailed studies found similar patient characteristics (symptomatic status, stenosis, and surgical risk) across different regions,12 more rigorous adjustment for patient factors might attenuate variations. However, it seems implausible that there are 7- to 10-fold differences in age-adjusted rates of symptomatic disease, comorbidity, or patient preferences by HRR. Variations are not likely due to differences in overuse because the use of CEA for “inappropriate” or “uncertain” indications has dropped dramatically since the RCTs. Nor did patterns of overuse explain variations at the surgeon or regional level prior to the RCTs.12,13 The “enthusiasm” hypothesis appears to be the leading explanation.12 This theory posits that variations are due to the distribution of physicians in a given area that are advocates of a procedure. Health care provider enthusiasm can be driven by similarly trained physicians or a local practice style that emphasizes intervention or new technologies, as well as market “supply” forces like the prevalence of physicians and hospitals who perform CEA and CAS. Prior work found that areas of high CEA use had 6-fold greater rates of high-volume surgeons.13 While enthusiasm for CEA may be waning, excitement about CAS is mounting, and major increases in uptake and variations in stenting are likely for many reasons. The preliminary results of 2 large international RCTs of CEA vs CAS have recently been published. The North American Carotid Revascularization Endarterectomy Stenting Trial (CREST) trial (composed of half symptomatic and asymptomatic patients) reported no differences in the primary composite outcome (periprocedural death, stroke, or myocardial infarction or subsequent ipsilateral stroke) at 4 years (Table).14 However, according to the composite end point used by the main CEA vs medical therapy RCTs, the 4-year rate of death or stroke in CREST was significantly higher for stenting than for surgery (6.4% vs 4.7%; P = .03). The European International Carotid Stenting Study (ICSS) trial of symptomatic patients found significantly higher rates of death, stroke, and MI for CAS at 30 and 120 days (Table).15 Both trials found that stenting was worse than surgery for patients older than 70 years. It is worth noting that the majority of Medicare beneficiaries undergoing revascularization in real-world practice, according to Patel et al, are older than 70 years, in whom stenting is riskier. These somewhat conflicting results will fuel the debate between CAS enthusiasts and skeptics about safety, efficacy, and indications for use. Market pressure will also be strong because stenting is performed by a much greater number of physicians and specialties (cardiologists, surgeons, and invasive radiologists) than CEA (surgeons). Together, this is expected to result in major pressure on Medicare to liberalize CAS coverage policy despite the findings that surgery is preferred to stenting for revascularization in persons older than 70 years Table. View LargeDownload Comparison of Study Characteristics and Outcomes of CEA, CAS, and Medical Therapy Just as CEA use shifted mostly to asymptomatic disease, between 70% to 90% of CAS patients are now asymptomatic as well. Since carotid atherosclerosis increases with age, an aging population combined with increases in vascular and brain imaging means more cases of asymptomatic carotid stenosis will be discovered. “Mission creep” toward stenting for patients at “average” risk is also likely to follow. Unfortunately, there is inadequate data on the long-term safety and efficacy of CAS for average-risk and asymptomatic patients to inform evidence-based practice and coverage policies. The outcomes of revascularization among Medicare patients reported by Patel et al are also a cause for concern because the mortality at 1 year for both procedures was equal to or greater than the combined outcomes in the RCTs at 4 and 5 years and not much better than the outcomes for medical therapy in the asymptomatic trials (Table). The higher periprocedural complication rates and more limited life expectancy seen in patients undergoing CEA or CAS in community practice greatly reduces or eliminates the potential long-term benefits of revascularization, especially among asymptomatic patients. For these reasons, the results of the ongoing SPACE-2 (Stent-Protected Angioplasty vs Carotid Endarterectomy) trial, a 3-arm RCT in asymptomatic patients comparing CEA and CAS with intensive medical management, will be very informative, since it remains unproven that either revascularization strategy is superior to modern, aggressive pharmacological risk factor reduction, especially in elderly patients. Such data are essential before widespread use of revascularization for elderly asymptomatic patients with carotid disease could be recommended. Better risk prediction tools are needed to help physicians individualize the short- and long-term risks and benefits of revascularization. Because carotid revascularization is a “preference-sensitive condition,” evidence-based decision aids should be developed to inform patients about the pros and cons of all their treatment options so that their preferences (and not just those of their physician) are heavily factored into a shared decision about treatment. Author Affiliations: Departments of Internal Medicine and Clinical Sciences, University of Texas Southwestern Medical Center, Dallas. Correspondence: Dr Halm, Departments of Internal Medicine and Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, PO Box 8889, Dallas, TX 75390 (ethan.halm@utsouthwestern.edu). Financial Disclosure: None reported. References 1. Tu JVHannan ELAnderson GM et al. The fall and rise of carotid endarterectomy in the United States and Canada. N Engl J Med 1998;339 (20) 1441- 1447PubMedGoogle ScholarCrossref 2. Winslow CMSolomon DHChassin MRKosecoff JMerrick NJBrook RH The appropriateness of carotid endarterectomy. N Engl J Med 1988;318 (12) 721- 727PubMedGoogle ScholarCrossref 3. Barnett HJTaylor DWEliasziw M et al. North American Symptomatic Carotid Endarterectomy Trial Collaborators, Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. N Engl J Med 1998;339 (20) 1415- 1425PubMedGoogle ScholarCrossref 4. Halliday AMansfield AMarro J et al. MRC Asymptomatic Carotid Surgery Trial (ACST) Collaborative Group, Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet 2004;363 (9420) 1491- 1502PubMedGoogle ScholarCrossref 5. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study, Endarterectomy for asymptomatic carotid artery stenosis. JAMA 1995;273 (18) 1421- 1428PubMedGoogle ScholarCrossref 6. Halm EATuhrim SWang JJRojas MHannan ELChassin MR Has evidence changed practice? appropriateness of carotid endarterectomy after the clinical trials. Neurology 2007;68 (3) 187- 194PubMedGoogle ScholarCrossref 7. Oddone EZHorner RDMonger MEMatchar DB Racial variations in the rates of carotid angiography and endarterectomy in patients with stroke and transient ischemic attack. Arch Intern Med 1993;153 (24) 2781- 2786PubMedGoogle ScholarCrossref 8. Halm EATuhrim SWang JJ et al. Racial and ethnic disparities in outcomes and appropriateness of carotid endarterectomy: impact of patient and provider factors. Stroke 2009;40 (7) 2493- 2501PubMedGoogle ScholarCrossref 9. Murad MHFlynn DNElamin MB et al. Endarterectomy vs stenting for carotid artery stenosis: a systematic review and meta-analysis. J Vasc Surg 2008;48 (2) 487- 493PubMedGoogle ScholarCrossref 10. Goodney PPTravis LLMalenka D et al. Regional variation in carotid artery stenting and endarterectomy in the Medicare population. Circ Cardiovasc Qual Outcomes 2010;3 (1) 15- 24PubMedGoogle ScholarCrossref 11. Groeneveld PWYang LGreenhut AYang F Comparative effectiveness of carotid arterial stenting versus endarterectomy. J Vasc Surg 2009;50 (5) 1040- 1048PubMedGoogle ScholarCrossref 12. Chassin MR Explaining geographic variations: the enthusiasm hypothesis. Med Care 1993;31 (5) ((suppl)) YS37- YS44PubMedGoogle ScholarCrossref 13. Chassin MRKosecoff JPark RE et al. Does inappropriate use explain geographic variations in the use of health care services? a study of three procedures. JAMA 1987;258 (18) 2533- 2537PubMedGoogle ScholarCrossref 14. CREST Investigators, Preliminary CREST data results. Paper presented at: International Stroke Conference February 26, 2010 San Antonio, TX 15. Ederle JDobson JFeatherstone RL et al. International Carotid Stenting Study Investigators, Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial. Lancet 2010;375 (9719) 985- 997PubMedGoogle ScholarCrossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Internal Medicine American Medical Association

The Good, the Bad, and the About-to-Get Ugly: National Trends in Carotid Revascularization: Comment on “Geographic Variation in Carotid Revascularization Among Medicare Beneficiaries, 2003-2006”

Halm, Ethan A.
Archives of Internal Medicine , Volume 170 (14) – Jul 26, 2010
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Publisher
American Medical Association
Copyright
Copyright © 2010 American Medical Association. All Rights Reserved.
ISSN
0003-9926
eISSN
1538-3679
DOI
10.1001/archinternmed.2010.223
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Abstract

The history of carotid endarterectomy (CEA) is a fascinating good news, bad news story. Wide geographic variations in the use of CEA have been noted for 3 decades, though its popularity has been cyclical. The use of CEA doubled in the early 1980s, but then dropped in half following reports of frequent complications1 and a national Medicare study reporting that one-third of CEAs were inappropriate.2 Subsequently, multinational randomized controlled trials (RCTs) found that, among carefully selected patients and surgeons, CEA reduced the risk of stroke and death compared with medical therapy. Symptomatic patients (with recent carotid stroke or transient ischemic attack), showed great benefit (absolute risk reduction in stroke of 8% per year) over 2 to 3 years.3 Asymptomatic patients had more modest benefit (absolute risk reduction of 1% per year) over 5 years.4,5 Good news followed these rare RCTs of surgery. Practice followed evidence and CEA use doubled.1 A population-based Medicare study also found dramatic declines in CEA for “inappropriate” and “uncertain” indications (32% to 9% and 32% to 4%, respectively), and non-RCT indications (70%-6%).6 The bad news was that despite the dramatic drop in overuse, nearly 1 in 11 CEAs were still deemed inappropriate, mostly in asymptomatic patients with high comorbidity.6 Paradoxically, there is also evidence that it is both underused and overused in minorities.7,8 There has also been “mission creep.” Carotid endarterectomy started out as revascularization for symptomatic patients, though now 70% to 80% of cases are for asymptomatic disease.6 Carotid angioplasty and stenting (CAS), the less-invasive but less well-proven endovascular alternative, is controversial. First-generation RCTs of CEA vs CAS in high-surgical-risk patients yielded mixed results about equivalence and raised concerns because short-term complications were high in both arms, and there was no data on long-term efficacy.9 In October 2004, Medicare restricted reimbursement for CAS to qualified health care providers in high-surgical-risk, symptomatic patients or those enrolled in RCTs or postmarketing studies. In this issue, the article by Patel et al represents an intriguing mix of more good and bad news. They examined Medicare claims from 2003 to 2006 to assess trends in CEA and CAS use by geographical hospital referral region (HRR) among patients 65 years or older. They found that CEA use fell 19%, and despite the Medicare restrictions, CAS increased 33%. Overall carotid vascularization rates dropped 6%. The bad news was that 10 to 15 years after publication of multiple RCTs and national guidelines, there was still 7- to 9-fold differences in age-adjusted CEAs rates across HRRs. There were also wide variations for CAS, perhaps less than CEA, but this is somewhat uncertain because 15% of HRRs had too few CAS cases to calculate stable rates. There was no correlation between use of CEA and CAS by region. A corroborating study of geographic variations in CEA and CAS in Medicare patients was recently published. Goodney et al10 used somewhat different methods but examined trends over a longer period. From 1998 to 2007, use of CEA declined 31% and CAS grew 4-fold, with a small net drop in carotid procedures.10 They also reported 10-fold variations in age, sex, and race-adjusted rates of CEA by HRR that were steady over time, 6-fold variations in CAS, and no correlation between regional rates of CEA and CAS. They and others also found ecological evidence that growth in CAS largely came at the expense of CEA.10,11 Patel et al acknowledge some key limitations of their study. More importantly, utilization studies do not shed light on “which rate is right” because they lack clinical information on symptom status, degree of carotid stenosis, and comorbidity needed to classify the indication for and appropriateness of revascularization. Since many hospitals and physicians perform these procedures within a given HRR, it would be more informative to see rates of overall use (and ideally overuse) analyzed at the hospital, specialty, and physician level. Critically left unmeasured are variations in underuse of carotid revascularization by HRR and health care provider, something not ascertainable via utilization data. What explains these variations? Conceptually, several patient, health care provider, and system factors could contribute via “supply” and “demand” dynamics. While most clinically detailed studies found similar patient characteristics (symptomatic status, stenosis, and surgical risk) across different regions,12 more rigorous adjustment for patient factors might attenuate variations. However, it seems implausible that there are 7- to 10-fold differences in age-adjusted rates of symptomatic disease, comorbidity, or patient preferences by HRR. Variations are not likely due to differences in overuse because the use of CEA for “inappropriate” or “uncertain” indications has dropped dramatically since the RCTs. Nor did patterns of overuse explain variations at the surgeon or regional level prior to the RCTs.12,13 The “enthusiasm” hypothesis appears to be the leading explanation.12 This theory posits that variations are due to the distribution of physicians in a given area that are advocates of a procedure. Health care provider enthusiasm can be driven by similarly trained physicians or a local practice style that emphasizes intervention or new technologies, as well as market “supply” forces like the prevalence of physicians and hospitals who perform CEA and CAS. Prior work found that areas of high CEA use had 6-fold greater rates of high-volume surgeons.13 While enthusiasm for CEA may be waning, excitement about CAS is mounting, and major increases in uptake and variations in stenting are likely for many reasons. The preliminary results of 2 large international RCTs of CEA vs CAS have recently been published. The North American Carotid Revascularization Endarterectomy Stenting Trial (CREST) trial (composed of half symptomatic and asymptomatic patients) reported no differences in the primary composite outcome (periprocedural death, stroke, or myocardial infarction or subsequent ipsilateral stroke) at 4 years (Table).14 However, according to the composite end point used by the main CEA vs medical therapy RCTs, the 4-year rate of death or stroke in CREST was significantly higher for stenting than for surgery (6.4% vs 4.7%; P = .03). The European International Carotid Stenting Study (ICSS) trial of symptomatic patients found significantly higher rates of death, stroke, and MI for CAS at 30 and 120 days (Table).15 Both trials found that stenting was worse than surgery for patients older than 70 years. It is worth noting that the majority of Medicare beneficiaries undergoing revascularization in real-world practice, according to Patel et al, are older than 70 years, in whom stenting is riskier. These somewhat conflicting results will fuel the debate between CAS enthusiasts and skeptics about safety, efficacy, and indications for use. Market pressure will also be strong because stenting is performed by a much greater number of physicians and specialties (cardiologists, surgeons, and invasive radiologists) than CEA (surgeons). Together, this is expected to result in major pressure on Medicare to liberalize CAS coverage policy despite the findings that surgery is preferred to stenting for revascularization in persons older than 70 years Table. View LargeDownload Comparison of Study Characteristics and Outcomes of CEA, CAS, and Medical Therapy Just as CEA use shifted mostly to asymptomatic disease, between 70% to 90% of CAS patients are now asymptomatic as well. Since carotid atherosclerosis increases with age, an aging population combined with increases in vascular and brain imaging means more cases of asymptomatic carotid stenosis will be discovered. “Mission creep” toward stenting for patients at “average” risk is also likely to follow. Unfortunately, there is inadequate data on the long-term safety and efficacy of CAS for average-risk and asymptomatic patients to inform evidence-based practice and coverage policies. The outcomes of revascularization among Medicare patients reported by Patel et al are also a cause for concern because the mortality at 1 year for both procedures was equal to or greater than the combined outcomes in the RCTs at 4 and 5 years and not much better than the outcomes for medical therapy in the asymptomatic trials (Table). The higher periprocedural complication rates and more limited life expectancy seen in patients undergoing CEA or CAS in community practice greatly reduces or eliminates the potential long-term benefits of revascularization, especially among asymptomatic patients. For these reasons, the results of the ongoing SPACE-2 (Stent-Protected Angioplasty vs Carotid Endarterectomy) trial, a 3-arm RCT in asymptomatic patients comparing CEA and CAS with intensive medical management, will be very informative, since it remains unproven that either revascularization strategy is superior to modern, aggressive pharmacological risk factor reduction, especially in elderly patients. Such data are essential before widespread use of revascularization for elderly asymptomatic patients with carotid disease could be recommended. Better risk prediction tools are needed to help physicians individualize the short- and long-term risks and benefits of revascularization. Because carotid revascularization is a “preference-sensitive condition,” evidence-based decision aids should be developed to inform patients about the pros and cons of all their treatment options so that their preferences (and not just those of their physician) are heavily factored into a shared decision about treatment. Author Affiliations: Departments of Internal Medicine and Clinical Sciences, University of Texas Southwestern Medical Center, Dallas. Correspondence: Dr Halm, Departments of Internal Medicine and Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, PO Box 8889, Dallas, TX 75390 (ethan.halm@utsouthwestern.edu). Financial Disclosure: None reported. References 1. Tu JVHannan ELAnderson GM et al. The fall and rise of carotid endarterectomy in the United States and Canada. N Engl J Med 1998;339 (20) 1441- 1447PubMedGoogle ScholarCrossref 2. Winslow CMSolomon DHChassin MRKosecoff JMerrick NJBrook RH The appropriateness of carotid endarterectomy. N Engl J Med 1988;318 (12) 721- 727PubMedGoogle ScholarCrossref 3. Barnett HJTaylor DWEliasziw M et al. North American Symptomatic Carotid Endarterectomy Trial Collaborators, Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. N Engl J Med 1998;339 (20) 1415- 1425PubMedGoogle ScholarCrossref 4. Halliday AMansfield AMarro J et al. MRC Asymptomatic Carotid Surgery Trial (ACST) Collaborative Group, Prevention of disabling and fatal strokes by successful carotid endarterectomy in patients without recent neurological symptoms: randomised controlled trial. Lancet 2004;363 (9420) 1491- 1502PubMedGoogle ScholarCrossref 5. Executive Committee for the Asymptomatic Carotid Atherosclerosis Study, Endarterectomy for asymptomatic carotid artery stenosis. JAMA 1995;273 (18) 1421- 1428PubMedGoogle ScholarCrossref 6. Halm EATuhrim SWang JJRojas MHannan ELChassin MR Has evidence changed practice? appropriateness of carotid endarterectomy after the clinical trials. Neurology 2007;68 (3) 187- 194PubMedGoogle ScholarCrossref 7. Oddone EZHorner RDMonger MEMatchar DB Racial variations in the rates of carotid angiography and endarterectomy in patients with stroke and transient ischemic attack. Arch Intern Med 1993;153 (24) 2781- 2786PubMedGoogle ScholarCrossref 8. Halm EATuhrim SWang JJ et al. Racial and ethnic disparities in outcomes and appropriateness of carotid endarterectomy: impact of patient and provider factors. Stroke 2009;40 (7) 2493- 2501PubMedGoogle ScholarCrossref 9. Murad MHFlynn DNElamin MB et al. Endarterectomy vs stenting for carotid artery stenosis: a systematic review and meta-analysis. J Vasc Surg 2008;48 (2) 487- 493PubMedGoogle ScholarCrossref 10. Goodney PPTravis LLMalenka D et al. Regional variation in carotid artery stenting and endarterectomy in the Medicare population. Circ Cardiovasc Qual Outcomes 2010;3 (1) 15- 24PubMedGoogle ScholarCrossref 11. Groeneveld PWYang LGreenhut AYang F Comparative effectiveness of carotid arterial stenting versus endarterectomy. J Vasc Surg 2009;50 (5) 1040- 1048PubMedGoogle ScholarCrossref 12. Chassin MR Explaining geographic variations: the enthusiasm hypothesis. Med Care 1993;31 (5) ((suppl)) YS37- YS44PubMedGoogle ScholarCrossref 13. Chassin MRKosecoff JPark RE et al. Does inappropriate use explain geographic variations in the use of health care services? a study of three procedures. JAMA 1987;258 (18) 2533- 2537PubMedGoogle ScholarCrossref 14. CREST Investigators, Preliminary CREST data results. Paper presented at: International Stroke Conference February 26, 2010 San Antonio, TX 15. Ederle JDobson JFeatherstone RL et al. International Carotid Stenting Study Investigators, Carotid artery stenting compared with endarterectomy in patients with symptomatic carotid stenosis (International Carotid Stenting Study): an interim analysis of a randomised controlled trial. Lancet 2010;375 (9719) 985- 997PubMedGoogle ScholarCrossref

Journal

Archives of Internal Medicine – American Medical Association

Published: Jul 26, 2010

Keywords: medicare,geographic difference

There are no references for this article.