224 Preoperative Cerebrovascular Consultation Mayo Clin Proc, February 2004, Vol 79 Table 1. Perioperative Ischemic Stroke Risk Rates for Specific Sur

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1 Mayo Clin Proc, February 2004, Vol 79 Preoperative Cerebrovascular Consultation 223 Concise Review for Clinicians The Preoperative Cerebrovascular Consultation: Common Cerebrovascular Questions Before General or Cardiac Surgery DAVID J. BLACKER, FRACP; KELLY D. FLEMMING, MD; MICHAEL J. LINK, MD; AND ROBERT D. BROWN, JR, MD, MPH All types of health care providers may be called on to evaluate the risk of ischemic stroke related to an upcoming surgical procedure, particularly in patients with established cerebrovascular disease. We outline possible mechanisms contributing to perioperative stroke, summarize available data on the stroke risk associated with selected surgeries, and highlight recognized risk factors. We then provide recommended answers to some of the questions commonly encountered at the preoperative cerebrovascular consultation: What is the appropriate time interval between a stroke and elective surgery? What is the perioperative stroke risk for patients with established carotid or vertebrobasilar large artery stenosis, and what are the cardiac implications of detecting a cerebrovascular large artery stenosis? Should patients with a large artery stenosis undergo prophylactic revascularization procedures before undergoing general surgery? What treatment is appropriate for patients with both coronary artery and carotid or vertebrobasilar large artery stenosis? What is the appropriate perioperative management of antiplatelet and anticoagulant medications with respect to stroke risk? Mayo Clin Proc. 2004;79: AF = atrial fibrillation; CABG = coronary artery bypass graft; CAS = carotid angioplasty and stenting; CEA = carotid endarterectomy; MI = myocardial infarction; TIA = transient ischemic attack As the population ages, increasing numbers of elderly patients are considered to be candidates for surgical procedures. Because of the association between age and cerebrovascular disease, physicians likely will be consulted more frequently than in the past to assess the risk of stroke related to surgical procedures in patients with cerebrovascular conditions and to advise appropriate treatment. The advent of readily available noninvasive neurovascular imaging and the evolving use of endovascular revascularization techniques increasingly raise the issue of whether prophylactic preoperative large artery neurovascular procedures are indicated. Risks vs benefits of any prophylactic intervention need to be carefully balanced on the basis of available data about perioperative stroke risk. We summarize the available literature and answer specific questions that commonly arise in the preoperative cerebrovascular consultation. Note that in some areas, the evidence-based data are not strong; therefore, recommendations should be viewed accordingly. From the Department of Neurology (D.J.B., K.D.F., R.D.B) and Department of Neurologic Surgery (M.J.L.), Mayo Clinic College of Medicine, Rochester, Minn. Dr Blacker is now with the Sir Charles Gairdner Hospital, Perth, Australia. A question-and-answer section appears at the end of this article. Address reprint requests and correspondence to Robert D. Brown, Jr, MD, MPH, Department of Neurology, Mayo Clinic College of Medicine, 200 First St SW, Rochester, MN ( brown.robert@mayo.edu). THEORETICAL REASONS FOR PERIOPERATIVE STROKE There are numerous reasons why the immediate perioperative period may pose an increased risk for cerebrovascular events. Potential stroke mechanisms include hypoperfusion (global or focal), thromboembolism (cardiac or artery-to-artery), and hematologic mechanisms. 1 Aortic or cardiac sources of perioperative emboli include aortic arch atherosclerosis, perioperative myocardial infarction (MI), and arrhythmias such as atrial fibrillation (AF). Paradoxical cerebral embolism via a patent foramen ovale could potentially cause a stroke in patients with pelvic or lower limb venous thrombosis; fat emboli entering into the venous system during orthopedic surgery is another potential stroke mechanism in the presence of a patent foramen ovale. Carotid and vertebrobasilar large artery stenoses are potential causes of perioperative stroke. Changes in flow and perfusion during surgery could result in focal hypoperfusion in the distribution of the stenosed artery. 2 Iatrogenic injury to neck arteries during surgical dissection or from misplaced vascular access lines are other potential mechanisms. Neck extension for endotracheal intubation reduces basilar artery flow in the presence of vertebral artery hypoplasia, and although not confirmed, may be a potential stroke mechanism. Transient compression or stretching of the neck arteries in drowsy postoperative patients may allow thrombus formation and subsequent distal embolization. Mayo Clin Proc. 2004;79: Mayo Foundation for Medical Education and Research

2 224 Preoperative Cerebrovascular Consultation Mayo Clin Proc, February 2004, Vol 79 Table 1. Perioperative Ischemic Stroke Risk Rates for Specific Surgeries and Clinical Conditions* Stroke risk Surgery (%) General surgery General surgery with 6 or without carotid bruit 0.5 General surgery after prior stroke General surgery with carotid stenosis and bruit or prior symptoms CABG retrospective studies CABG prospective studies CABG surgery after prior stroke or TIA CABG surgery + valve surgery CABG surgery + unilateral >50% carotid stenosis CABG surgery + bilateral >50% carotid stenosis CABG surgery + carotid occlusion Surgery with symptomatic vertebrobasilar stenosis *CABG = coronary artery bypass graft; TIA = transient ischemic attack. Hematologic mechanisms may contribute to both ischemic and hemorrhagic perioperative stroke. The postoperative state is associated with changes in blood-clotting mechanisms, 3 and the withholding of antiplatelet or anticoagulant medications during the perioperative period might contribute to the risk of perioperative vascular events. Finally, there is a body of literature 4 concerning the relationship between infectious and inflammatory conditions and vascular disease; whether this issue is applicable to the postoperative state is not known. STROKE RISK RELATED TO SELECTED SURGERIES The stroke risk rates associated with specific surgical procedures and clinical situations are presented in Table It is useful to consider cardiac and general surgeries separately because cardiac patients often have more generalized atherosclerotic disease and the surgical procedures in these patients have an inherent risk for stroke. General surgery has an extremely low stroke risk in unselected patients of about 0.2%. 5 RISK FACTORS FOR PERIOPERATIVE STROKE The risk factor linked most consistently to perioperative ischemic stroke is a history of stroke. One study of 173 patients with a history of stroke found a 2.9% risk of stroke when patients underwent subsequent general surgeries. 7 Other factors that increase the stroke risk related to general surgeries include postoperative cardiac arrhythmias, peripheral vascular disease, 5 and chronic obstructive airway disease. In patients who underwent coronary artery bypass graft (CABG) surgery, a history of stroke or transient ischemic attack (TIA) increased the perioperative stroke rate to 8.5%, 1 compared with an overall risk of 1% to 2%. Stroke after CABG surgery is associated with advanced age, probably related to increased carotid stenosis and aortic arch atherosclerosis in older patients. Other risk factors include prolonged cardiopulmonary bypass, recent MI, left main stem coronary artery disease, repeated cardiac surgery, ventricular thrombus, postinfarction angina, cardiac failure, diabetes, smoking, and impaired renal function. 1 QUESTIONS COMMONLY ENCOUNTERED AT THE PREOPERATIVE CEREBROVASCULAR CONSULTATION Timing of Surgery in Relation to Stroke How long should general surgery under anesthesia be delayed after a stroke? Every patient who has had a stroke should be examined before undergoing elective nonurgent surgery so that the stroke mechanism can be defined and the optimal secondary prevention strategies can be clarified. This should include appropriate vascular imaging (eg, carotid ultrasonography, magnetic resonance angiography and/or computed tomographic angiography), cardiac studies (eg, electrocardiography and/or echocardiography when indicated), and any indicated blood tests. 9 Before undergoing general or cardiac surgery, symptomatic patients with an extracranial carotid stenosis greater than 70% should receive appropriate treatments including carotid endarterectomy (CEA) 10 or carotid angioplasty and stenting (CAS) in selected patients. There are few data to guide the timing of surgery in relation to stroke. Although some information regarding timing of surgery can be found in studies of CEA, most pertains to the risk of reperfusion hemorrhage, which is probably not an issue in other forms of surgery. There is information in the cardiac surgery literature 11,12 that pertains to patients with acute stroke who require urgent cardiac surgery; however, the data on the risk according to timing are conflicting and are often in the setting of infective endocarditis. Because clinical data are scant, we also consider pathophysiological data in our recommendations. There are theoretical reasons for recommending a delay between ischemic stroke and surgery, so that the brain may recover sufficiently before encountering the hemodynamic stresses associated with surgery and anesthesia. Recovery of cerebral autoregulation after stroke is an important factor that should be considered. The duration of markedly impaired autoregulation after stroke is unclear but is probably from days to 1 to 2 weeks. Pathologically, a cerebral infarct undergoes a series of changes mediated by inflammatory cells that soften the tissue and could potentially make it vulnerable during anesthesia and surgery to either hemorrhagic transformation or worsening ischemia. Ideally, sufficient time should pass for both these processes to occur; a month should be sufficient for most patients

3 Mayo Clin Proc, February 2004, Vol 79 Preoperative Cerebrovascular Consultation 225 including those with a moderately large cerebral infarct (greater than one third the distribution of the middle cerebral artery). Promptly examine all stroke patients, and defer nonessential surgery until the evaluation is complete. Treat symptomatic carotid stenosis with CEA or CAS before the patient undergoes general or cardiac surgery. Allow at least 1 month to elapse between a moderately large ischemic stroke (greater than one third the distribution of the middle cerebral artery) and surgery. Large Artery Stenosis and Surgery What is the stroke risk for patients with established carotid or vertebrobasilar large artery stenosis who undergo a surgical procedure, and what are the cardiac implications of detecting a cerebrovascular large artery stenosis? Most data suggest that carotid bruits and asymptomatic carotid stenoses do not increase the perioperative stroke risk related to noncardiac surgeries. 6,13 The issue is complicated by a study of patients with carotid bruits or prior cerebral ischemic symptoms in whom carotid ultrasonography was performed within 12 months before general surgery; the study found a perioperative stroke rate of 3.6% in these patients. 8 No clear relationship was found between severity of stenosis and stroke risk, although the increased risk may have been explained by the history of stroke. Patients found to have a carotid bruit at preoperative evaluation should undergo a detailed neurovascular history and examination. If there are no symptoms or signs of focal cerebral ishemia, then no further evaluation is necessary before general surgery. Patients with carotid stenosis who undergo CABG surgery have a higher risk of stroke than do those without carotid stenosis (Table 1). Although carotid stenosis is positively correlated with stroke after CABG surgery, this may be because carotid stenosis is a marker for advanced systemic atherosclerosis, specifically aortic arch atherosclerosis, rather than being causative for ischemic strokes. 1 Less than half of the increased risk is likely to be due to the carotid lesion. 1 Few data exist relating to the perioperative stroke risk associated with intracranial large artery stenosis; however, this issue is becoming more common as more patients undergo magnetic resonance angiography or computed tomographic angiography of the intracranial arteries as part of the cerebrovascular work-up. Recent data have shown that patients with symptomatic basilar or intracranial vertebral artery stenosis who undergo various vascular and nonvascular surgeries have a perioperative stroke risk of 6.0%, with prolonged intraoperative hypotension being implicated as a potential precipitating factor. 2 There are no data regarding perioperative stroke risk in the setting of large artery stenosis in the anterior intracranial circulation. Patients with extracranial internal carotid artery stenosis may have concurrent advanced coronary artery disease, which may be a concern in the perioperative period. Approximately 50% of patients with large artery ischemic stroke and no cardiac history have abnormal cardiac stress test results. 14 Summary and Asymptomatic carotid bruits and stenoses do not increase the stroke risk for patients who undergo general surgery. Carotid bruits and/or stenoses in asymptomatic and symptomatic patients who undergo CABG surgery are associated with a 5% to 7% risk of stroke. Symptomatic vertebrobasilar stenosis is associated with a 6% risk of stroke in patients who undergo general surgery or CABG surgery. The perioperative stroke risk in patients with intracranial large artery stenosis in the anterior circulation is unknown but is likely to be similar to the risk in symptomatic patients with vertebrobasilar stenosis (6%); the risk is likely to be extremely low in asymptomatic patients. Patients with large artery ischemic stroke should undergo an appropriate preoperative cardiac examination. Prophylactic Large Artery Surgery or Endovascular Repair Should a patient with a large artery stenosis undergo prophylactic revascularization procedures before undergoing general surgery? To determine whether a patient s perioperative stroke risk will be reduced by a prophylactic neurovascular procedure requires that the risk of this procedure be balanced against that of the intended subsequent surgery. The revascularization procedure will not entirely remove the perioperative stroke risk, particularly related to cardiac procedures, because there are other potential mechanisms for ischemic stroke (eg, aortic arch atherosclerosis). Any prophylactic neurovascular procedure followed by another surgery exposes a patient to the risk of periprocedural stroke twice. Although the prophylactic procedure is intended to reduce the perioperative stroke risk of the subsequent surgery, it will not reduce the risk to zero. The stroke risks related to CEA and endovascular procedures in various clinical circumstances are summarized in Table A further issue is the use of antiplatelet agents such as clopidogrel after stenting procedures. These medications are typically prescribed for at least several weeks to main-

4 226 Preoperative Cerebrovascular Consultation Mayo Clin Proc, February 2004, Vol 79 Table 2. Stroke Risk Related to Carotid Intervention* Stroke risk Procedure (%) CEA Asymptomatic stenosis (ACAS) Symptomatic stenosis (NASCET) Asymptomatic patients (AHA guidelines) 16 <3.0 Endovascular procedure ICA extracranial stent alone Stent + protection device Intracranial angioplasty and stent 19 (range 20 ) <10 (4-40) *ACAS = Asymptomatic Carotid Atherosclerosis Study; AHA = American Heart Association; CEA = carotid endarterectomy; ICA = internal carotid artery; NASCET = North American Symptomatic Carotid Endarterectomy Trial. tain stent patency. At least 1 week, and preferably 2 weeks, of clopidogrel cessation is necessary to allow platelet function to recover 21 to lessen the risk of hemorrhagic complications during subsequent surgery. The issue of prophylactic repair usually pertains to patients with asymptomatic large artery stenosis or to those with a distant history of cerebral ischemia because CEA or CAS is the standard of care for patients with symptomatic carotid artery stenosis. Because the perioperative stroke risk is low in patients with asymptomatic carotid stenosis, prophylactic CEA and screening for carotid artery stenosis in asymptomatic patients cannot be recommended. Few data exist about the approach to patients with intracranial arterial stenosis. For patients with actively symptomatic intracranial stenoses, it would seem reasonable to delay surgery as long as possible, aggressively treat the neurovascular disease, and possibly allow time for collateral vessel formation. The stroke and death rates for intracranial angioplasty and stenting procedures currently are based on a small series and range between 4% to 40%, 20 although some researchers believe that complication rates are less than 10%. 19 The stroke risk related to intracranial stenting likely exceeds the perioperative stroke risk for general surgery in asymptomatic patients and for many symptomatic patients. Patients with symptomatic extracranial carotid stenosis should undergo CEA or stenting before elective general surgery. Patients with recent symptomatic intracranial large artery stenosis should have surgery delayed for at least 1 month. Intraoperative hypotension must be avoided. There are insufficient data to make a recommendation for prophylactic endovascular revascularization procedures; however, the stroke risk from these procedures likely exceeds the stroke risk in these patients during general surgery. Patients with asymptomatic extracranial large artery stenosis do not require CEA or CAS before general surgery; the risks associated with CEA or CAS are higher than the perioperative stroke risk. Patients with asymptomatic intracranial arterial stenosis do not require preoperative intervention because the perioperative risks are lower than those for angioplasty and stenting. Combined Cardiac and Carotid Artery Stenosis What treatment is appropriate for patients with both coronary artery and carotid or vertebrobasilar large artery stenosis? Many patients undergoing cardiac procedures also have cerebrovascular disease. Studies examining the stroke risk during CABG surgery related to varying degrees of carotid stenosis are difficult to interpret because of their retrospective nature, small number of cerebral events, lack of data on the topography of the strokes, and the fact that some data are from CABG surgery combined with CEA. Naylor et al 1 noted the prevalence of carotid bruits in patients who underwent CABG surgery to be 9.9%; the prevalence was 6.8% in patients who underwent CABG surgery with a history of stroke or TIA. Although there is a relationship between carotid artery stenosis and the risk of stroke during CABG surgery (for reasons noted previously), extracranial carotid artery stenosis probably accounts for less than half the strokes related to CABG surgery. 1 Naylor et al 1 summarized the literature and derived the stroke risk rates according to varying degrees of carotid stenosis (Table 1). The treatment of patients with both symptomatic and asymptomatic cerebral and coronary lesions has been a subject of extensive discussion. Some researchers have recommended a simple treatment protocol that can be summarized as operate first on the symptomatic vascular lesion, and then treat the asymptomatic lesion at a later time. When there are active symptoms in both territories, a combined procedure may be considered. 22 Treatment guidelines are less clear-cut in patients with asymptomatic carotid stenosis who are to undergo CABG surgery. Most of the literature provides combined data from CABG procedures and CEA, yielding a perioperative stroke rate of 3.8%, MI rate of 3.2%, and death rate of 4.6%. 23 A staged approach, in which the CEA is performed before CABG surgery, has been studied less; it may have a lower stroke rate at 1.8% but at the expense of more MIs at 9.1% and more deaths at 6.6%. 23 A reversed staged approach, in which CABG surgery is done first and later followed by CEA, has the least number of studied patients and seems to yield a comparable percentage of strokes at 3.2%, but fewer MIs at 1.6% and deaths at 2%. 23 One metaanalysis 24 compared rates from combined CEA and CABG

5 Mayo Clin Proc, February 2004, Vol 79 Preoperative Cerebrovascular Consultation 227 surgery and found the combined approach had higher rates of stroke or death than staged approaches. Researchers recommended combined surgeries only for patients with symptoms in both circulations, for high-risk asymptomatic patients with bilateral high-grade stenosis, or for a highgrade carotid stenosis with a contralateral occlusion. 24 Although some researchers have suggested that prophylactic CEA simultaneous with CABG surgery is an acceptable indication for CEA, 16 others have concluded that there is no evidence from the substantive literature to suggest that this practice (or the staged approach) reduces stroke or death rates in this patient group. 23 The role of prophylactic carotid stenting for patients with combined coronary and carotid large artery stenosis is evolving. Currently, in patients not undergoing cardiac surgery, stenting for asymptomatic carotid stenosis cannot be routinely advised because there are insufficient data to support benefit; this is in contrast to CEA, for which a statistically significant benefit has been shown. 15 Because many potential mechanisms of ischemic stroke are related to CABG surgery, treatment of the carotid stenosis does not entirely remove the stroke risk for an individual patient. In patients having both coronary and extracranial large artery stenosis with one symptomatic and one asymptomatic circulation, the symptomatic lesion should be treated first with a staged procedure. Patients with symptomatic, active lesions in both circulations may consider combined CEA and CABG surgery; when possible, CAS should be considered for the extracranial carotid stenosis. Patients with isolated, asymptomatic unilateral carotid stenosis should not have combined CABG surgery and CEA because stroke and death rates are increased. If the asymptomatic lesion is treated at all, these patients could have a staged procedure, acknowledging that the MI and death rates may be higher when CEA or CAS is done first, although the stroke rate may be lowered. Selected high-risk asymptomatic patients (ie, with bilateral stenosis or contralateral occlusion) may consider combined CEA and CABG surgery; when possible, CAS should be considered as the initial procedure. Perioperative Management of Antiplatelet and Anticoagulant Medications How should antiplatelet and anticoagulant medications be managed in the perioperative period with respect to stroke risk? Many clinicians can recall patients who have had vascular events temporally related to the discontinuation of antiplatelet or anticoagulant medications. Case reports and series do little to accurately quantify the risk of this situation because many other patients safely undergo temporary discontinuation without adverse events. Theoretical models 25 have been used to estimate the risk of stroke in patients with AF when anticoagulation is temporarily withheld; these estimates are based on the annual stroke risks observed in large studies of AF. The models assume that the stroke risk during the perioperative period is no greater than at any other period without the protection of anticoagulation; for reasons cited earlier, this may not necessarily be the case. A review of 31 studies of anticoagulant management in the perioperative period found a stroke risk of 0.4%. 26 In a study of patients with AF who required warfarin cessation for endoscopy, the risk of stroke was 1.06% within 30 days of the procedure. Factors that put patients at higher risk for stroke included older age; history of hypertension, hyperlipidemia, or stroke; and family history of vascular disease. 27 In general, early postprocedure anticoagulation with heparin or low-molecular-weight heparin is recommended in patients with a history of stroke or other major risk factors for perioperative stroke. Withholding antiplatelet medications in the perioperative period may have adverse consequences. Studies from the cardiac literature have reported that MI, ischemic stroke, and other thrombotic events occur more frequently in patients not given aspirin in the immediate postoperative period after CABG surgery. 28 Because of the bleeding risk associated with other antiplatelet agents such as clopidogrel, these agents are commonly withheld for about 1 week (and preferably 2 weeks) before the patient undergoes surgical procedures. The risk of thrombotic events with shortterm clopidogrel cessation is unknown. The risk of thrombotic events occurring when anticoagulation is withheld for procedures in patients with AF or cardiac heart valve prostheses is low, but is higher in selected patients with risk factors. Aggressive, early postprocedure anticoagulant management (ie, with heparin or low-molecular-weight heparin) is recommended in patients with a history of stroke or other major risk factors for perioperative stroke. If a patient has been taking aspirin, particularly for secondary prevention of vascular events, this should be continued throughout the perioperative period unless the procedure has a high risk of hemorrhagic complications. Other agents such as clopidogrel are usually stopped for at least 1 week and preferably 2 weeks because of the risk of perioperative hemorrhage. CONCLUSIONS Although stroke related to surgical procedures represents a small percentage of the total stroke burden, it occurs in a

6 228 Preoperative Cerebrovascular Consultation Mayo Clin Proc, February 2004, Vol 79 potentially predictable group of patients in whom careful assessment and management might feasibly reduce the likelihood of stroke. With the increasing availability of vascular procedures such as angioplasty and stenting, we anticipate that an increasing number of patients will be assessed for prophylactic vascular intervention before elective surgery. There is some danger that unnecessary procedures could be performed that have a higher stroke risk than that posed by the index surgery; this danger makes careful consideration of the perioperative stroke risk imperative. Careful comparison of the risks of a vascular intervention to the stroke risk reduction possibly promoted by the procedure are needed in patients with cerebrovascular disease requiring general, cardiac, or other surgery. REFERENCES 1. Naylor AR, Mehta Z, Rothwell PM, Bell PR. Carotid artery disease and stroke during coronary artery bypass: a critical review of the literature. Eur J Vasc Endovasc Surg. 2002;23: Blacker DJ, Flemming KD, Wijdicks EF. Risk of ischemic stroke in patients with symptomatic vertebrobasilar stenosis undergoing surgical procedures. Stroke. 2003;34: Rem J, Feddersen C, Brandt MR, Kehlet H. Postoperative changes in coagulation and fibrinolysis independent of neurogenic stimuli and adrenal hormones. Br J Surg. 1981;68: Zebrack J, Anderson JL. The role of inflammation and infection in the pathogenesis and evolution of coronary artery disease. Curr Cardiol Rep. 2002;4: Larsen SF, Zaric D, Boysen G. Postoperative cerebrovascular accidents in general surgery. Acta Anaesthesiol Scand. 1988;32: Ropper AH, Wechsler LR, Wilson LS. Carotid bruit and the risk of stroke in elective surgery. N Engl J Med. 1982;307: Landercasper J, Merz BJ, Cogbill TH, et al. Perioperative stroke risk in 173 consecutive patients with a past history of stroke. Arch Surg. 1990;125: Evans BA, Wijdicks EF. High-grade carotid stenosis detected before general surgery: is endarterectomy indicated? Neurology. 2001;57: Brown RD Jr, Evans BA, Wiebers DO, Petty GW, Meissner I, Dale AJ, Mayo Clinic Division of Cerebrovascular Disease. Transient ischemic attack and minor ischemic stroke: an algorithm for evaluation and treatment. Mayo Clin Proc. 1994;69: Barnett HJ, Taylor DW, Eliasziw 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: Zisbrod Z, Rose DM, Jacobwitz IJ, Kramer M, Acinapura AJ, Cunningham JN Jr. Results of open heart surgery in patients with recent cardiogenic embolic stroke and central nervous system dysfunction. Circulation. 1987;76(5, pt 2):V109-V Maruyama M, Kuriyama Y, Sawada T, Yamaguchi T, Fujita T, Omae T. Brain damage after open heart surgery in patients with acute cardioembolic stroke. Stroke. 1989;20: Gerraty RP, Gates PC, Doyle JC. Carotid stenosis and perioperative stroke risk in symptomatic and asymptomatic patients undergoing vascular or coronary surgery. Stroke. 1993;24: Chimowitz MI, Poole RM, Starling MR, Schwaiger M, Gross MD. Frequency and severity of asymptomatic coronary disease in patients with different causes of stroke. Stroke. 1997;28: Executive Committee for the Asymptomatic Carotid Atherosclerosis Study. Endarterectomy for asymptomatic carotid artery stenosis. JAMA. 1995;273: Biller J, Feinberg WM, Castaldo JE, et al. Guidelines for carotid endarterectomy: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Circulation. 1998;97: Wholey M, Toursarkissian B, Ferral H. Current status in cervical carotid artery stent placement. Semin Cerebrovasc Med Stroke. 2002;2: Wholey MH. The ARCHeR Trial: results for carotid stenting in high surgical risk patients: preliminary 30 day results. Presented at: 52nd Annual Scientific Session of the American College of Cardiology; Chicago, Ill; March 30, Gomez CR, Orr SC. Angioplasty and stenting for primary treatment of intracranial arterial stenoses. Arch Neurol. 2001;58: Chimowitz MI. Angioplasty or stenting is not appropriate as first-line treatment of intracranial stenosis. Arch Neurol. 2001;58: Kam PC, Nethery CM. The thienopyridine derivatives (platelet adenosine diphosphate receptor antagonists), pharmacology and clinical developments. Anaesthesia. 2003;58: Caplan LR. Caplan s Stroke: A Clinical Approach. 3rd ed. Boston, Mass: Butterworth-Heinemann; 2000: Barnes RW, Robertson JT. Surgical considerations in asymptomatic disease. In: Barnett HJM, Mohr JP, Stein BM, Yatsu FM. Stroke Pathophysiology, Diagnosis, and Management. 3rd ed. New York, NY: Churchill Livingstone; 1998: Borger MA, Fremes SE. Management of patients with concomitant coronary and carotid vascular disease. Semin Thorac Cardiovasc Surg. 2001;13: Spandorfer J. The management of anticoagulation before and after procedures. Med Clin North Am. 2001;85: Dunn AS, Turpie AG. Perioperative management of patients receiving oral anticoagulants: a systematic review. Ann Intern Med. 2003;163: Blacker DJ, Wijdicks EF, McClelland RL. Stroke risk in anticoagulated patients with atrial fibrillation undergoing endoscopy. Neurology. 2003;61: Mangano DT, Multicenter Study of Perioperative Ischemia Research Group. Aspirin and mortality from coronary bypass surgery. N Engl J Med. 2002;347: Questions About the Preoperative Cerebrovascular Consultation 1. Which one of the following regarding stroke and general surgery is most accurate? a. Asymptomatic carotid stenosis is a risk factor for perioperative stroke b. Patients with symptomatic carotid stenosis are at high risk for stroke and should have this condition treated before undergoing other surgeries c. Carotid bruits are a marker for increased risk of perioperative stroke d. Middle cerebral artery stenosis has been shown to predict perioperative stroke e. Aortic arch atherosclerosis is a risk factor for perioperative stroke related to general surgery

7 Mayo Clin Proc, February 2004, Vol 79 Preoperative Cerebrovascular Consultation Which one of the following best describes the relationship between extracranial carotid stenosis and stroke related to CABG surgery? a. Carotid stenosis may cause a stroke during CABG surgery due to focal hypoperfusion, particularly if there is intraoperative hypotension b. Carotid stenosis may be a nidus for cerebral embolism during or after CABG surgery c. Carotid stenosis may be the cause of stroke or be a marker for aortic arch atherosclerosis that is the cause of stroke related to CABG surgery d. Carotid stenosis increases with age, which is the overwhelming factor predicting stroke related to CABG surgery e. The stroke mechanisms related to CABG surgery are too complex to be sure of the relationship 3. Which one of the following regarding CEA and CAS is true? a. CAS is an acceptable treatment for all patients with asymptomatic carotid stenosis b. Intracranial angioplasty and stenting should be performed for an asymptomatic midbasilar stenosis before CABG surgery c. CEA or CAS should be performed in patients with a 75% internal carotid artery stenosis and recent ipsilateral amaurosis fugax before elective abdominal surgery d. CEA or CAS should be performed in patients with an asymptomatic carotid bruit before CABG surgery for recent unstable angina e. Combined CEA and CABG surgery should be performed in patients with symptomatic carotid stenosis and a distant history of MI but with recent normal cardiac stress test results 4. Regarding the perioperative use of antiplatelet and anticoagulant medications, which one of the following is false? a. Clopidogrel should be continued throughout the perioperative period in a patient with an asymptomatic 80% carotid stenosis who is undergoing CABG surgery b. Aspirin should be continued throughout the perioperative period in a patient undergoing CABG surgery who has no history of stroke or TIA c. Early postoperative heparin is reasonable treatment for a patient with AF and a history of stroke who has an elective repair of an abdominal aortic aneurysm d. It would be reasonable to withhold warfarin for a few days and to not use heparin in a 55-year-old patient with nonvalvular AF who is undergoing elective clipping of an unruptured intracranial aneurysm e. Aspirin should be continued throughout the perioperative period in a 75-year-old patient with a history of stroke who is undergoing an open cholecystectomy 5. Which one of the following is true? a. A unilateral carotid bruit predicts a 3% chance of stroke during CABG surgery b. The procedure-related stroke risk for CEA in asymptomatic patients is greater than the stroke risk for CAS c. Carotid occlusion is associated with an increased risk for stroke related to CABG surgery d. The stroke risk related to general surgery is greater for patients with a distant history of stroke than for those with carotid stenosis e. The procedure-related stroke risk for CEA in asymptomatic patients with carotid stenosis is greater than the risk of general surgery in the setting of carotid stenosis Correct answers: 1. b, 2. c, 3. c, 4. a, 5. c