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Presidential address: carotid endarterectomy, under attack again!

2003; Elsevier BV; Volume: 37; Issue: 6 Linguagem: Inglês

10.1016/s0741-5214(02)75343-3

1097-6809

James O. Menzoı́an,

Intracranial Aneurysms: Treatment and Complications

It has been a pleasure and an honor to serve as the 29th President of the New England Society for Vascular Surgery, the oldest regional vascular society in the United States. I would like to share with you some thoughts I have about the current environment of carotid artery surgery. There are a number of innovative changes currently developing in our specialty, which makes this a very exciting time. What role some of the many new technologies will have in future vascular practice only time will tell. I am not here to praise or to condemn carotid artery stenting. Currently there are eight trials or registries in various states of activity trying to determine what exact role carotid artery stenting will play in the treatment of patients with extracranial carotid artery disease. In my opinion, there are currently no level I data available to help us make a clinical decision about using these new modalities for our patients at this time. I am concerned that we are losing sight of what we currently have available for the treatment of patients with carotid artery disease. Some have suggested that carotid endarterectomy results are not as good as have been suggested by the results of national trials. I would like to take this opportunity to reflect on some of the issues relevant to these suggestions. I apologize for the somewhat negative tone of my title, but I do believe that at this time carotid endarterectomy is under attack again, and I hope to help set the record straight. The report by Eastcott et al1Eastcott HHG, Pickering GW, Rob CG. Reconstruction of internal carotid artery in a patient with intermittent attacks of hemiplegia. Lancet 1954;2:994-6Google Scholar in 1954 represents where it all began and when the operation began to gain popularity. Although Carrea et al2Carrea R Molins M Murphy M Surgical treatment of spontaneous thrombosis of the internal carotid artery in the neck carotid-carotideal anastomosis.Acta Neurol Latinoamer. 1955; 1: 71-78Google Scholar did perform carotid surgery, which was an external carotid to internal carotid anastomosis, they did not report this case until 1955. Strully et al3Strully K.J Hurwitt E.S Blankenberg H.W Thrombo-endarterectomy for thrombosis of the internal carotid artery in the neck.J Neurosurg. 1953; 10: 474-482Crossref PubMed Scopus (53) Google Scholar reported in 1953 an attempt at thrombectomy of the internal carotid artery, but retrograde flow could not be established, and the artery was ligated. DeBakey4DeBakey M.E Successful carotid endarterectomy for cerebrovascular insufficiency.JAMA. 1975; 233: 1083-1085Crossref PubMed Scopus (224) Google Scholar did a carotid endarterectomy, using the technique we now know, in 1953, but this was not reported until 1975. I believe that the operation performed at St Mary's Hospital in 1954 by Eastcott and colleagues and published in The Lancet in 1954 opened the door to our thinking that correction of extracranial carotid artery disease could improve neurologic symptoms. Prior to the operation the patient, a 66-year-old woman, had 33 attacks of transient cerebral ischemia. After surgery the symptoms were gone. For many years after that operation there were arguments on both sides of the fence for and against the operation as being successful in the treatment of patients with neurologic symptoms. Even more heatedly argued was the role of carotid endarterectomy in asymptomatic patients with high-grade carotid stenosis. To address some of these concerns, I would like to address four questions. It was not until the 1990s that a large number of randomized trials were undertaken. These demonstrated that carotid endarterectomy was beneficial for patients with significant carotid artery stenosis and transient ischemic attacks, and in addition the operation also was beneficial to patients with significant carotid artery stenosis who were without symptoms. Reports from the NASCET [North American Symptomatic Carotid Endarterectomy Trial],5North American Symptomatic Carotid Endarterectomy Trial CollaboratorsBeneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis.N Engl J Med. 1991; 325: 445-453Crossref PubMed Scopus (7401) Google Scholar the VA [Veterans Administration] Cooperative Trial,6Hobson R.W Weiss D.G Fields W.S Goldstone J Moore W.S Towne J.B et al.Efficacy of carotid endarterectomy for asymptomatic carotid stenosis.N Engl J Med. 1993; 328: 221-227Crossref PubMed Scopus (1167) Google Scholar and the ACAS [Asymtomatic Carotid Atherosclerosis Study]7Executive Committee for the Asymptomatic Carotid Atherosclerosis StudyEndarterectomy for asymptomatic carotid stenosis.JAMA. 1995; 273: 1421-1428Crossref PubMed Scopus (4852) Google Scholar indicated the benefit of surgical treatment of carotid artery disease, but there were numerous concerns that the operation was being overutilized. Others were concerned that the results reported in these trials could not be reproduced in practice. As reported in the Dartmouth Atlas of Vascular Health Care,8Huber T.S Seeger J.M Dartmouth Atlas of Vascular Health Care review impact of hospital volume, surgeon volume, and training on outcome.Vasc Surg. 2001; 34: 751-756Abstract Full Text Full Text PDF Scopus (40) Google Scholar the number of carotid endarterectomy procedures performed between 1983 and 1996 showed a marked increase after the publication of these trials. Between 1995 and 1997 the number of carotid endarterectomies done in the United States doubled, from 62,000 to 144,000. The number of carotid endarterectomies done in Medicare recipients reached a high of 144,000 in 1997. In addition, there was some concern that the rate of carotid endarterectomy carried out in Medicare recipients varied considerably in various regions of the United States, even after adjustment for differences in age, sex, race, and illness rates of the local population. The rate of carotid endarterectomy ranged from 1 to 7.5 per thousand Medicare enrollees. Numerous articles have appeared in the literature, with such titles as "Carotid endarterectomy: Where do we draw the line?,"9Gorelick PB. Carotid endarterectomy: where do we draw the line? Stroke 1999;30:1745-50Google Scholar "Carotid endarterectomy: Another wake-up call,"10Barnett H.J.M Broderick J.P Carotid endarterectomy another wake-up call.Neurology. 2000; 55: 746-747Crossref PubMed Scopus (15) Google Scholar and "Complication rates for carotid endarterectomy: A call to action."11Goldstein L.B Moore W.S Robertson J.T Chaturvedi S Complication rates for carotid endarterectomy a call to action.Stroke. 1997; 28 ([editorial]): 889-890Crossref PubMed Scopus (57) Google Scholar These articles imply that "we" have overdone it and that results outside of trials are really not that good. This is an important question because unless carotid endarterectomy can be done with acceptable morbidity and mortality the benefits of this prophylactic operation cannot be achieved. For example, the ACAS trial demonstrated an annualized absolute risk reduction of 1.1% per year. This was achieved with a perioperative stroke and death rate of 2.3%. However, others have argued that if the perioperative stroke and death rate were 3% there would be no benefit to carotid endarterectomy in this population. Consequently, the question raised by some as to whether the efficacy demonstrated in trials could be achieved in clinical practice is a good question.12Chaturvedi S Aggarwal R Murugappan A Results of carotid endarterectomy with prospective neurologist follow-up.Neurology. 2000; 55: 769-772Crossref PubMed Scopus (69) Google Scholar Randomized trials generally exclude high-risk patients to clearly define the benefit of the treatment arm. For example, in the NASCET and ACAS trials, exclusion criteria included previous carotid surgery, previous myocardial infarction, history of congestive heart failure, unstable angina, renal failure, respiratory failure, cancer, and combined carotid and coronary bypass surgery patients. We need to consider whether the patients we see in clinical practice, outside of trials, can have results similar to those obtained in trials. A review of 25 studies reporting 30-day stroke and death rates suggested a 30-day mortality of 1.3% in asymptomatic patients and 1.8% in symptomatic patients. The combined stroke and death rate was 3% in asymptomatic patients and 5.2% in symptomatic patients.13Rothwell P.M Slattery J Warlow C.P A systematic comparison of the risks of stroke and death due to carotid endarterectomy for symptomatic and asymptomatic stenosis.Stroke. 1996; 27: 266-269Crossref PubMed Scopus (163) Google Scholar A report from Olmstead County in Minnesota comparing their operative results for carotid endarterectomy with the NASCET trial showed similar favorable results.14Hallett J.W Pietropaoli J.A Ilstrup D Gayari M Williams J.A Meyer F.B Comparison of North American Symptomatic Carotid Endarterectomy Trial and population-based outcomes for carotid endarterectomy.Vasc Surg. 1998; 27: 845-851Abstract Full Text Full Text PDF Google Scholar Exclusion of high-risk subjects from these trials is of concern. However, there are reports that show those similar favorable results in trial-eligible and trial-ineligible patients.15Lepore M.R Sternbergh W.C Khashayar S Tonnessen B Money S.R Influence of NASCET/ACAS trial eligibility on outcome after carotid endarterectomy.Vasc Surg. 2001; 34: 581-586Abstract Full Text Full Text PDF Scopus (65) Google Scholar Ricotta16Gasparis AP, Ricotta L, Cuadra SA, Purtill WA, van Bemmelen PS, Hines GL, et al. High risk carotid endarterectomy: fact or fiction. J Vasc Surg 2003;37:40-6Google Scholar presented data at a recent national vascular meeting that showed that operative results of carotid endarterectomy were not statistically different in "normal risk" and "high risk" patients, including myocardial infarction, transcient ischemic attack, stroke, or death. Collectively these data suggest that results of carotid endarterectomy in clinical practice can be similar to those results obtained in national trials. There is much discussion now about the relationship between operative volumes and clinical outcomes. It has been suggested that high volume is associated with better outcomes. Many questions arise here. Is it hospital volume or is it surgeon volume? If there is a correlation between volume and outcomes, why is that? Is it that "practice makes perfect" or that there is a selective referral to those hospitals or those physicians known to get good results? So hospitals and surgeons with higher volume have better systems in their institutions, resulting in better outcomes? A recent study addresses the correlation between hospital volume and various surgical procedures and surgical mortality.17Birkmeyer J.D Siewers A.E Finlayson E Stukel T.A Lucas F.L Batista I et al.Hospital volume and surgical mortality in the United States.N Engl J Med. 2002; 346: 1128-1137Crossref PubMed Scopus (3850) Google Scholar The report shows that surgical mortality decreases as hospital volume increases for 14 different surgical procedures. However, the impact of volume varied considerably among the different operative procedures. For example, the difference between surgical mortality for pancreatic resection when comparing high-volume hospitals with low-volume hospitals was considerable, 3.8% versus 16.3%. For carotid endarterectomy the difference in surgical mortality between high-volume hospitals and low-volume hospitals was 1.5% versus 1.7%. The conclusion of this report was that Medicare patients undergoing certain operative interventions could significantly reduce their risk for operative death by selecting a high-volume hospital. Data from the Dartmouth Atlas8Huber T.S Seeger J.M Dartmouth Atlas of Vascular Health Care review impact of hospital volume, surgeon volume, and training on outcome.Vasc Surg. 2001; 34: 751-756Abstract Full Text Full Text PDF Scopus (40) Google Scholar show that there is a difference in 30-day mortality for carotid endarterectomy when comparing low-volume, medium-volume, and high-volume institutions. High-volume institutions had the lowest 30-day mortality, with results comparable to those of the major trial hospital, but what constituted low volume, medium volume, and high volume was not defined. In the same Dartmouth Atlas there are data showing the 30-day mortality rates for surgeons based on the number of carotid endarterectomy procedures done per year. For surgeons who performed 3 or fewer carotid endarterectomies per year, 30-day mortality was 2.8%, whereas for surgeons who performed 43 or more procedures per year, operative mortality was 1.4%. This report also showed that for carotid endarterectomy, for institutions that did more than 40 procedures per year, adjusted mortality was 1.7%, and for institutions that did more than 110 procedures per year, adjusted mortality was 1.5%. A report by Ruby et al18Ruby S.T Robinson D Lynch J.T Outcome analysis of carotid endarterectomy in Connecticut the impact of volume and specialty.Ann Vasc Surg. 1996; 10: 22-26Abstract Full Text PDF PubMed Scopus (80) Google Scholar also shows a difference in combined stroke and death rates when comparing surgeons who did 1 or less carotid endarterectomy procedures per year with surgeons who did more than 10 procedures. Most of these studies demonstrate a positive correlation between volume and favorable outcomes, but there is a large amount of variation in these reports. The variation is probably related to what we mean by high and low volume. There is institutional variability; there is variability in results, depending on the procedure; and also there is variability in results when comparing surgeons. The question still is, If higher volume does equal better outcome, why is that? It could be that practice makes perfect. The more you do, the better you as a surgeon get. The more a hospital does a particular operation, the better the hospital gets. It could be that these better results have something to do with the processes of care. That is, higher volume surgeons or higher volume hospitals have a better system worked out for doing these procedures. It could be that the implementation of specific actions or treatment plans makes the difference. These issues remain unresolved, but some providers have already begun to make reimbursement decisions based on these correlations. For example, Leapfrog represents a coalition of private and public purchasers of health insurance. Leapfrog is composed of more than 100 Fortune 500 companies that purchase health care and are now insisting on stringent safety standards.19Birkmeyer J.D Finlayson E Birkmeyer C.M Volume standards for high-risk surgical procedures potential benefits of the Leapfrog initiative.Surgery. 2001; 130: 415-422Abstract Full Text Full Text PDF PubMed Scopus (460) Google Scholar Because the Leapfrog group purchases more than $53 billion worth of health care each year, they are starting to impose certain requirements on institutions who care for their employees, which include measures to ensure patient safety and reduce the cost of care. These initiatives include a computerized physician order entry system, evidence-based hospital referrals, and intensive care units staffed with credentialed physicians. In my state of Massachusetts, regulatory agencies have asked hospitals to report to insurance providers whether they meet Leapfrog standards. The Leapfrog group is advocating standards for evidence-based hospital referrals, and in this list of standards are hospital volume characteristics, which include minimum volume characteristics, as follows: coronary artery bypass surgery, 500 procedures per year; coronary angioplasty, 400 procedures per year; abdominal aortic aneurysm repair, 30 procedures per year; esophageal cancer surgery, 7 procedures per year; and carotid endarterectomy, 100 procedures per year. They do suggest that in geographic areas where scientifically rigorous risk-adjusted hospital outcome comparisons are publicly reported, favorable risk-adjusted outcomes will replace the favorable volume characteristics. According to Leapfrog, there is a requirement of 100 carotid endarterectomies in an institution for it to be a favorable environment for their insured individuals. To gather information about operative volume, I asked various associations in each of the six New England states for data on the number of carotid endarterectomy procedures per hospitals in 2000 and 2001. The associations were CHIME [College of Healthcare Information Management Executives] Incorporated of the Connecticut Hospital Association, the Massachusetts Health Data Consortium, the Maine Health Data Association, the New Hampshire Hospital Association, the Vermont VAHHS [Veterans Affairs Department of Health and Human Services], and the Hospital Association of Rhode Island. The Figure shows the number of carotid endarterectomies done in each of 128 hospitals in the six New England states. You will see that there are only 13 hospitals in New England that perform 100 or more carotid endarterectomies per year. The Table shows how many hospitals in New England would qualify if the number of carotid endarterectomies per year were reduced to other levels. It is clear from this table that if 100 carotid endarterectomies per year were required, only 10% of the hospitals in New England would qualify. If that number were reduced to 50 procedures per year, then 39% of the hospitals in New England would qualify.TableNumber of hospitals that would qualify at various volumes of carotid endarterectomy procedures performedCEA/yearHospitals (n = 128)10013901980235044258110117CEA, Carotid endarterectomy. Open table in a new tab CEA, Carotid endarterectomy. The potential problems to patients and physicians in New England are obvious. Using volume as a surrogate for quality, hospitals and surgeons will be required to increase their volume of carotid endarterectomy procedures. Where are they going to find this volume? If one assumes that all patients with symptomatic carotid stenosis are currently undergoing appropriate operative intervention, then the only place for growth in volume is in patients who have asymptomatic carotid stenosis. The temptation may be great to lower our standards and to operate on less than optimal candidates and to perhaps operate on carotid stenoses below the levels suggested by ACAS. The Leapfrog criteria would also have an adverse effect on manpower distribution in New England. A young surgeon who is looking for a place to practice will be quite leery of practicing in a community whose surgical volume is less than Leapfrog requirements. In addition, there is the potential for problems with access to health care by our patients. If carotid endarterectomy can only be done in certain hospitals, our patients will be forced to travel, perhaps a considerable distance, for this type of care. It should also be mentioned that data from the National VA Surgical Quality Improvement Program show no correlation between volume and quality outcome.20Khuri S.F Daley J Henderson W.G et al.the participants in the National VA Surgical Quality Improvements ProgramThe Department of Veterans Affairs' NSQIP the first national, validated, outcome-based, risk-adjusted, and peer-controlled program for the measurement and enhancement of the quality of surgical care.Ann Surg. 1998; 228: 491-507Crossref PubMed Scopus (1268) Google Scholar The volume considerations are masking the real issue that we need to focus on. Although there is a correlation between volume and quality of care, this correlation does not establish a cause-effect relationship. The more important questions are how one interprets the correlation and what decisions one makes. There are examples of high volume with poor results and low volume with good results. Also, where does one draw the line? There are numerous examples of good quality results with less than 100 carotid endarterectomies per year. Other questions need to be answered about this volume outcome relationship.21Lee C.N Daly J.M Provider volume and clinical outcomes in surgery issues and implications.ACS Bull. 2002; 87: 21-26Google Scholar Does this relationship diminish over time? Is there a threshold effect beyond which no more improvement is made above a certain volume, or is there the possibility of worsening results above a certain volume? Is there a learning curve, and what is the shape of this learning curve? Is the learning curve different for experienced or new surgeons? How important is cumulative lifetime volume? Is there a difference in outcomes when comparing an older surgeon who has been practicing for many years but whose volume is less than that suggested by Leapfrog when compared with a young surgeon in a high-volume practice almost immediately? Finally, does experience with similar procedures contribute to a favorable outcome? For example, perhaps we are looking at the wrong thing when we look at a specific operation, and rather we should be looking at a cluster of operative procedures that have great similarity. To quote John Daly, "Provider volume itself is not the equivalent of Healthcare. Rather, it serves as a proxy for quality."21Lee C.N Daly J.M Provider volume and clinical outcomes in surgery issues and implications.ACS Bull. 2002; 87: 21-26Google Scholar Are there things we can do to improve carotid endarterectomy? In my opinion, there are a number of considerations that are important. We need to be sure that our indication for the procedure is appropriate. NASCET and ACAS have clearly defined those patients who are likely to benefit from carotid endarterectomy. We must be careful not to extend the indications into areas that have not been shown to be beneficial. Risk assessment of our patients is essential. Patients at higher risk for operative intervention than was present in national randomized trials can have good results, but we must be attentive to the careful preoperative evaluation of such patients to minimize operative morbidity and mortality. I believe that accepted performance measurements for carotid endarterectomy have been defined. Perioperative transient ischemic attack, stroke, myocardial infarction, local nerve injury, and death are clearly defined and measurable. We must all track our patients and know our results in all of these important areas. I believe that we need to set benchmark standards for results with various operations, especially with carotid endarterectomy. It has been clearly demonstrated that the perioperative morbidity and mortality that were achieved in national trials can be achieved in individual practice, and we must insist that these benchmarking standards be adhered to at our own institutions. We must be open to the concept of system change. There are some systematic issues in our institutions and in our practice that can make a difference. For example, marking the operative site, something that many of us did not enthusiastically embrace, has been shown to be very beneficial in reducing mistakes. There are numerous other system changes that we need to be aware of. It could be that those institutions that have higher volumes with good results and those institutions with lower volumes with good results have achieved these results not only because of the skill of the surgeon and the appropriate selection of the patient but also because there are institutional systems in place to ensure good results. Finally, I believe that the use of protocols can be very helpful. If the community of surgeons can agree on certain issues regarding clinical care, then perhaps protocols should be established to ensure that all surgeons adhere to the protocol. For example, it is clearly shown that preoperative anti-platelet therapy reduces perioperative mortality and stroke, that the use of intraoperative heparin during carotid endarterectomy is beneficial, and, finally, patch closure of the endarterectomized segment ensures less recurrent carotid stenosis.22Kresowik T.F Bratzler D Karp H.R Hemann R.A Hendel M.E Grund S.L et al.Multistate utilization, process, and outcomes of carotid endarterectomy.J Vasc Surg. 2001; 33: 227-235Abstract Full Text Full Text PDF PubMed Scopus (123) Google Scholar If all the surgeons practicing in an institution adhere to protocols, perhaps results would improve and perhaps lower volume institutions and surgeons could get equally good results. In summary, are there good data supporting carotid endarterectomy? The answer is, unequivocally, yes. Are results from trials achievable in clinical practice? The answer is, unquestionably, yes. Is there an association between volume and quality outcomes? Yes, but the question remains, what does it mean? Although high-volume institutions do get good results, there are also examples of low-volume institutions also getting good results. Finally, can we improve our results with carotid endarterectomy? The answer is an unqualified yes. I believe that monitoring your own personal results very closely, paying attention to published reports of ways to improve operative results, picking the right operation for the right patient and careful attention to preoperative preparation and postoperative care can only help to improve our collective results with carotid endarterectomy. I have focused on carotid endarterectomy because of the current discussion as to the relative merits of this operation, which I believe are unfounded. However, I am convinced that the suggestions I have made to ensure quality care of patients with carotid artery disease can be transferred to any type of practice. Simply stated, I think we need to understand and appreciate the excellent information we have about the merits of carotid endarterectomy. Trying to understand the reasons for better results in high-volume hospitals, rather than focusing merely on volume, is very important. Adhering to established clinical protocols, close monitoring of personal results, and demanding accepted benchmark results are essential. As long as we are open minded about new treatment modalities and if we adhere to the principle of evidence-based medicine, practicing vascular surgeons will enjoy an excellent reputation and will enjoy the respect of the patients they are privileged to care for. I have enjoyed the honor and privilege of serving as the 29th President of the New England Society of Vascular Surgery. I look forward to our Society's continued growth.