Risk Neutralization in Cardiac Operations: Detection and Treatment of Associated Carotid Disease

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1 Risk Neutralization in Cardiac Operations: Detection and Treatment of Associated Carotid Disease John Parker Gott, MD, Vinod H. Thourani, MD, Carolyn E. Wright, MS, W. Morris Brown III, MD, Andrew B. Adams, BS, George M. Skardasis, MD, William M. McKinnon, MD, Patrick M. Battey, MD, and Robert A. Guyton, MD Carlyle Fraser Heart Center, Crawford Long Hospital of Emory University, Division of Cardiothoracic Surgery, Department of Surgery, Emory University School of Medicine, Atlanta, Georgia Background. A screening and treatment protocol was implemented to extend the benefit of prophylactic carotid endarterectomy to patients who had open heart operations. Methods. Patients aged 65 or older or who at any age had left main coronary disease, transient ischemic attack, or stroke were eligible for preoperative carotid duplex screening. Carotid endarterectomies and open heart operations were planned as a staged (n 59) or combined procedure (n 55) for angiographically confirmed carotid stenosis of at least 80%. Results. Duplex scans were obtained in 1,719 of 7,035 open heart surgical patients over 8 years. The overall stroke rate was 1.5% (108 of 7,035). Seven of these were strokes of carotid origin (0.1%). There were 129 patients with at least 80% stenosis. One hundred fourteen had carotid endarterectomy preceding open heart operation, and none had carotid artery stroke. Twelve patients with at least 80% carotid stenosis by duplex scan had open heart operations without prophylactic carotid endarterectomies. There were four carotid strokes in these 12 patients (p ; odds ratio, 20.2). Stroke risk remained significantly elevated (16.8%, p 0.005) in the 50% to 79% group. The changes associated with the reduced risk afforded by this screening and treatment strategy amounted to $346 for each patient in the study. Conclusions. The risk of carotid stroke at the time of cardiac operation can be defined by duplex screening. Prophylactic carotid endarterectomy neutralizes the risk in those with at least 80% stenosis. Consideration for lowering the threshold for assessment and treatment of carotid stenoses appears warranted. The economic investment is recouped by the savings in system resources that would have been depleted through care for carotid stroke and its sequelae. (Ann Thorac Surg 1999;68:850 7) 1999 by The Society of Thoracic Surgeons Extracranial cerebrovascular disease is second only to the atherosclerotic ascending aorta as a risk factor for perioperative stroke in cardiac surgical patients [1]. The overall stroke rate in a recent, large, multicenter, prospective series of cardiac surgical patients was about 2% [1]. The presence of untreated stenosis 80% or greater in the internal carotid artery increased the stroke risk to 15% to 20% [2 5]. The prevalence of carotid stenoses of this magnitude in the cardiac surgical population is 6% to 12% [2, 6]. Symptoms and physical examination detect and define carotid disease poorly [3, 6, 7]. An effective screening strategy must identify significant stenoses in asymptomatic patients. High-risk markers have been identified which can guide screening efforts [2]. The most effective treatment for significant asymptomatic or symptomatic carotid disease is carotid endarterectomy [8]. This report details implementation of a strategy designed Presented at the Forty-fifth Annual Meeting of the Southern Thoracic Surgical Association, Orlando, FL, Nov 12 14, 1998 Address reprint requests to Dr Gott, Carlyle Fraser Heart Center, Crawford Long Hospital of Emory University, Suite 7700, 550 Peachtree St, Atlanta, Georgia 30365; john_gott@emory.org to detect and treat concurrent carotid disease to lower the risk of perioperative stroke in cardiac surgical patients. Material and Methods All adult patients who had cardiac operation at Crawford Long Hospital of Emory University from January 1, 1991, through September 30, 1998, comprised the population for this study. A protocol for evaluation of associated extracranial cerebrovascular disease was applied. Patients who had a history of transient ischemic attack, reversible ischemic neurologic deficit, stroke, or other central nervous system complaints suggestive of extracranial cerebrovascular disease; those with 50% or greater left main coronary disease; and patients aged 65 years or older were eligible for preoperative duplex scan of their carotid arteries. In addition to a qualitative duplex report, stenoses were reported in ranges ( 49%, 50% to 79%, 80% to 99%, and occluded). For patients with screening suggestive of an 80% or greater stenosis, selective carotid arteriography was done. If arteriography confirmed the 80% or greater stenosis, a combined or 1999 by The Society of Thoracic Surgeons /99/$20.00 Published by Elsevier Science Inc PII S (99)

2 Ann Thorac Surg GOTT ET AL 1999;68:850 7 CAROTID/CARDIAC OPERATIONS 851 Fig 1. Bar graph showing increasing application of duplex screening over time as overall cardiac surgical volume increased. staged carotid and cardiac operation was planned. The angiographic criteria were strict and followed the standards of the North American Symptomatic Carotid Endarterectomy Trial [8]. The decision to do a combined or staged carotid and coronary operation was made jointly between vascular and cardiac surgeons and was individualized for the patient. Unscreened patients with a new stroke noted postoperatively had a postoperative duplex scan to assess carotid involvement. The following pragmatic definition for carotid stroke was chosen: a unihemispheric stroke ipsilateral to an 80% or greater carotid stenosis or ipsilateral to carotid endarterectomy. Most patients who had carotid endarterectomy (CEA) were operated on in a staged fashion, with endarterectomy done using sedation and local or regional anesthetic techniques. Cardiac operation typically followed in 1 to 3 days. Intraoperative carotid shunting and vein patches were used selectively. For combined operations, the patient was positioned and prepared using general anesthesia. The carotid operation was completed in all cases before instituting extracorporeal circulation. The so-called reverse-stage procedure, in which the cardiac operation precedes the CEA, was not used because of the documented higher risk for neurologic injury with that strategy [4]. Cardiac operations were done on cardiopulmonary bypass with a variety of selectively applied cardioplegic myocardial protection techniques. No patients who had limited access or beating heart operations had contemporaneous (same admission) CEA in this series. For patients in whom a grade II or greater atherosclerotic or calcific ascending aorta was discovered, a no-clamp, cold fibrillatory arrest technique was often used. Logistic regression and discriminant function analyses were used to delineate group membership using categoric dependent variables. Analysis of variance and the Student s t test were used to examine the differences between groups with continuous variables. A 2 test was used to examine the significance between groups using categorical variables. Results The carotid stroke reduction strategy was implemented during a phase of growth in cardiac surgical volume at Crawford Long Hospital (Fig 1). The protocol was inconsistently applied at the outset because of resource limitations, differing degrees of confidence in the strategy among staff, and other logistical issues. Addition of vascular laboratory personnel (one-half of a full-time equivalent position, 0.5 $36,000 yearly compensation), addition of another scanner ($160,000) to the existing two, improved communication regarding scheduling, the learning curve effect (at the outset a bilateral carotid scan took 45 minutes; currently it takes 15 minutes), and continuous education of the team have facilitated application of the protocol. The results of the 1,719 duplex scans are shown in graphic form in Figure 2. Eighty-four percent of patients (n 1,440) had less than 50% stenosis, 7.3% (n 125) had carotid stenosis of 50% to 79%, 7.5% (n 129) had stenosis greater than 80%, and 1.5% (n 25) had an occluded carotid artery. There were 108 strokes of all types recognized in the 7,035 patients, for an overall incidence of 1.5%. Fifty-nine percent of those strokes could be categorized as shown in Figure 3. None of the indeterminate strokes occurred in patients with carotid stenoses greater than 80%. The patients in whom screening showed a carotid stenosis less than 50% by definition did not have carotid strokes and had a significantly lower overall stroke rate compared with patients with stenoses greater than 50% (Table 1). The risk of carotid stroke was neutralized in patients for whom the detection and treatment protocol was followed. There were no carotid strokes in the 114 patients who had a duplex scan showing greater than 80% stenosis confirmed by arteriogram and followed by carotid endarterectomy. The histogram in Figure 4 shows the distribution by age of patients who had a combined procedure. The overall operative mortality rate was 2.4%. Patients who had isolated coronary artery bypass (primary or reoperative) had an operative mortality rate of 1.2%.

3 852 GOTT ET AL Ann Thorac Surg CAROTID/CARDIAC OPERATIONS 1999;68:850 7 Fig 2. Representation of carotid duplex scan results for the 1,719 patients, arrayed by age and severity of carotid disease. Tight stenoses are seen in the younger strata, which reinforces that advanced age should not be the sole screening criterion. The mortality rate for patients who had a perioperative stroke was over sixfold higher (15.7%). The demographics, intraoperative markers, and outcomes were similar for the staged versus combined CEA groups, with a few exceptions (Table 2). The 114 patients who had combined procedures had an overall operative mortality rate of 4.4%, a stroke rate of 3.5%, and a perioperative myocardial infarct rate of 1.8%. Operations for more advanced or unstable carotid or coronary artery disease and reoperations tended to be combined. The in-hospital outcome of the patients arrayed by the detection and treatment algorithm is shown in Figure 5. Of the 15 patients with an 80% or greater stenosis who did not have CEA, 8 had arteriography that showed a lesser degree of stenosis. These 8 patients had a cardiac operation without carotid operation and and had no neurologic complications. After learning of the carotid screening results in 3 patients, the surgeon deferred cardiac operation. One of these patients was morbidly obese, 1 had a malignancy, and 1 had extensive vascular disease. These 3 patients were alive and without stroke as of October The 4 remaining patients with greater than 80% stenoses had cardiac operations without prophylactic endarterectomy, and all had fatal carotid artery strokes. In 3 patients the surgeon elected to forgo angiography and proceed with cardiac operation. One patient had angiography, and a combined carotid and coronary operation was planned. The evening before the scheduled operation a papillary muscle ruptured and the patient was operated on emergently for shock. At awakening, neurologic findings were normal, but within 12 hours hemiplegia developed and progressed to uncal herniation and death. Only 1 of 25 patients with a preoperative carotid occlusion known by duplex screen had a new stroke. Of 17 patients who had a new stroke and had not had preoperative duplex screen, only 1 was found at postoperative duplex screen to have an occluded carotid artery. The course after discharge for the 114 patients who had combined carotid and cardiac operations is shown in Figure 6. The average hospital charge for cardiac operations during the study period was $39,309. The average hospital charge for contemporaneous (same admission) carotid and coronary artery operations was $53,018. Additional economic considerations are addressed in the Appendix. Comment Perioperative stroke is arguably the most catastrophic complication of cardiac operations. In addition to grave personal loss, there are indirect costs to society through lost productivity as well as the direct economic cost of medical care during the remaining lifetime. Postoperative stroke ranks immediately below the low-output state as the second leading cause of operative death [9]. The Fig 3. Distribution of perioperative strokes by cause. In many previous series carotid artery stroke accounted for up to a third of perioperative strokes.

4 Ann Thorac Surg GOTT ET AL 1999;68:850 7 CAROTID/CARDIAC OPERATIONS 853 Table 1. Distribution of Strokes by Duplex Stratification and Treatment Carotid Stroke n (%) Other Stroke n (%) Total Strokes n/total (%) Duplex Screening Result 3 (.06) 33 (0.6) 36/5,316 (0.7) Not done 0 42 (2.9) a 42/1,440 (2.9) 50% 0 4 (3.5) 4/114 (3.5) > 80% had CEA 0 21 (16.8) 21/125 (16.8) b 50% 79% no CEA 4 (33.3) c 1 (6.7) 5/12 (41.7) d > 80% no CEA a p compared with the 50% to 79% group and the 80% stenosis no carotid endarterectomy group, and significantly higher than the unscreened patients. b p 0.001, 50% to 79% group compared with 50% group and p compared with 80% stenosis with carotid endarterectomy group. c p compared with all other carotid groups. d p compared with all other groups for total incidence of strokes. CEA carotid endarterectomy. Fig 4. Distribution by age of patients who had combined carotid and cardiac operations. Despite the age screening criterion ( 65 years), inclusion of left main coronary artery disease and previous central nervous system criteria led to detection of significant stenoses in the younger patients. incidence of stroke after cardiac operation is related to advanced age, which parallels the accelerated involvement of the aorta and brachiocephalic vessels with atherosclerotic plaque [9]. Age appears to be less the issue per se and more a marker for atherosclerosis, which is involved in at least two thirds of adverse neurologic outcomes after coronary bypass operations. The trend toward operation in an increasingly elderly population underscores the growing problem. Neurologic injury after cardiac operation has been studied recently in a large, multi-institutional, prospective study [1]. The classification of immediate neurologic outcome has clarified the discussion of magnitude of injury, cost, mechanism, and strategies for risk reduction. Type I injuries are predominantly focal stroke, transient ischemic attack, and fatal cerebral injuries. This type is characteristic of carotid or macroembolic stroke. Type II outcomes are more global or diffuse, with disorientation or immediate, usually reversible, generalized cognitive decline and have been associated with microembolization. Type I injury occurs in 3.1% of patients, is responsible for a 21% post coronary bypass mortality rate, 11-day intensive care unit stay, 25 days in-hospital, at least an additional $10,266 in-hospital boarding charge, and a charge of five to ten times the in-hospital charge for rehabilitative and outpatient support [1]. These consequences confirm the importance of stroke risk reduction strategies outlined here. Carotid artery disease is associated significantly with type I neurologic outcome ( p 0.001) [1]. Hemodynamically significant carotid stenoses are associated with up to 30% of early postoperative coronary bypass strokes [10]. The prevalence of significant carotid disease in the cardiac surgical population in the current era reflects the systemic nature of the atherosclerotic process: 17% to 22% of patients have 50% or greater stenosis and 6% to 12% have 80% or greater carotid artery stenosis [2, 6]. Perioperative stroke risk was less than 2% for patients with carotid artery stenoses less than 50%, 10% for untreated stenoses between 50% and 80%, and 11% to 18.8% in patients with untreated stenoses greater than 80% [4, 5]. Untreated bilateral highgrade stenoses or an occluded carotid artery and con Fig 5. Algorithm demonstrating elimination of risk of carotid artery stroke with aggressive detection and treatment. Inclusion of carotid endarterectomy (CEA) for patients with carotid stenoses greater than 80% significantly reduced the risk for carotid type stroke (CVA) (p ; odds ratio, 20.2).

5 854 GOTT ET AL Ann Thorac Surg CAROTID/CARDIAC OPERATIONS 1999;68:850 7 Table 2. Analysis of Staged Versus Combined Carotid and Cardiac Operations Variable Staged Combined Overall p Value Number of patients Age (y) Gender (% male) Diabetes (%) Hypertension (%) Elevated cholesterol (%) Previous CABG (%) Previous CEA (%) Previous MI (%) Preoperative CNS symptoms LVEF (%) Smoking (%) PVD (%) CPB time (min) Cross-clamp time (min) LOS (days) Postoperative MI (%) Postoperative stroke (%) In-hospital mortality (%) CABG coronary bypass; CEA carotid endarterectomy; CNS central nervous system; CPB cardiopulmonary bypass; LOS total length of stay; LVEF left ventricular ejection fraction; MI myocardial infarction; PVD peripheral vascular disease. tralateral high-grade stenosis are uncommon but set the stage for a one-in-five chance of stroke [11, 12]. The incidence and degree of carotid stenosis in this study were similar to those of recent series. These associations form the basis for recognition of high-risk patients and allow modification of operative strategy to reduce stroke risk. Escalating risk of stroke with increasing severity of carotid artery disease is evident in Table 1. Carotid artery disease is a direct threat and also serves as a marker for generalized atherosclerosis, risk of aortic atheroembolism, and intracranial cerebrovascular disease. The inference that carotid endarterectomy for patients with 80% or greater stenosis neutralized the risk of carotid artery stroke is supported by the observed decrease of stroke rate in that group to the level seen in screened patients with no or mild carotid stenoses. Screening Medical history and physical examination are of little help in risk assessment. Absence of symptoms referable to carotid artery disease is not reassuring: carotid stenosis of greater than 75% in the neurologically asymptomatic patient is an independent predictor of stroke risk immediately after coronary artery bypass (odds ratio, 9.9; p 0.005) [10, 13]. The presence or absence of a cervical bruit is poorly predictive as well. Even with known symptomatic carotid artery disease a focal bruit does not predict high-grade stenosis (sensitivity 63%, specificity 61%) [7]. A previous prospective study of preoperative carotid duplex scanning of 1,087 patients who had open heart operations aged 65 years or older defined the following markers associated with important (80%) carotid stenosis: female gender, peripheral vascular disease, previous transient ischemic attack or stroke, smoking history, or left main coronary artery disease ( p 0.05) [2]. If all patients with at least one of these risk factors were screened, 95% of those with an 80% stenosis would be detected and 91% of those with a 50% stenosis would be detected. As noted in the discussion of that paper, this requires almost all (85%) patients 65 years old or older to be screened to detect these stenoses. The results have reaffirmed the strong correlation between carotid stenosis and advanced age but also suggested that the lower age limit at which carotid artery screening becomes resource efficient is not yet known. Current data suggest that it is prudent to screen at least all patients aged 65 years or older. This recommendation may be broadened with additional data. Patients with significant left main coronary artery disease should be screened at any age because of the strong association between it and carotid stenosis. Patients with a previous transient ischemic attack or stroke should be screened independent of age, and echocardiography should be considered to screen for a cardiac or aortic embolic source. Operative Management When surgical treatment of concurrent carotid and coronary artery disease is planned, the procedures can be done in either a combined or staged fashion. Superiority of one approach has not been established by prospective trial and remains controversial. Decisions are currently best left to local team policies and preferences based on careful examination of team outcomes. An individualized, patient-specific, selective approach with the decision based on symptoms and the relative severity of extracranial cerebrovascular disease and coronary artery

6 Ann Thorac Surg GOTT ET AL 1999;68:850 7 CAROTID/CARDIAC OPERATIONS 855 Fig 6. Actuarial curves demonstrating survival and freedom from new stroke (CVA) after release from hospital. disease appears prudent. Recent series have an overall mortality rate of about 4% and a permanent neurologic deficit rate in about 4% of patients [14]. Some observational series have suggested that combined carotid and coronary operations carried a higher risk for in-hospital stroke and death compared with patients in the same institution having a staged procedure [15 18]. A uniform policy of combined operation for all patients with concurrent carotid and coronary artery disease recently has been shown to be a safe approach and might lower overall resource requirements [14]. The selective, individualized approach outlined here demonstrated no significant difference in safety of the staged versus the combined operation. Central nervous system risk is significantly increased when the reverse-staged procedure is used, wherein the coronary artery bypass precedes the CEA by 1 or more days during the same hospitalization. A prospective, randomized trial studying the outcome of that strategy found a much higher risk of stroke when CEA followed (14%) rather than preceded (2.8%, p 0.05) coronary artery bypass; however, mortality rates were similar [19]. Cerebral revascularization should precede coronary revascularization. The exception is the uncommon situation of the truly emergent, unstable coronary artery bypass patient in whom CEA should follow closely after the heart operation. Limitations The limitations of the current study include the uncertainty in attributing cause of a particular stroke in a given patient. The widely known difficulties in determining cause of stroke after cardiac operation were certainly evident here, as 41% of patients in this series had an unknown cause of stroke (Fig 3). The pragmatic aspects of the study design were based on the increasing acceptance by the medical community of the effectiveness of prophylactic endarterectomy for stroke prevention in patients with hemodynamically significant (70% to 80%) carotid stenoses and the reliability and availability of the duplex screening technology. Prevailing opinion precluded offering prophylactic endarterectomy to patients with carotid stenosis less than 80% but greater than 50%, and lack of an effective operation precluded surgical treatment for the few patients with carotid artery occlusion. Our goal was to determine whether prophylactic CEA could reduce the risk of early postoperative stroke in patients with 80% or greater stenosis. For this specific application, therefore, carotid artery stroke was defined as a unihemispheric stroke occurring ipsilateral to 80% or greater carotid stenosis or ipsilateral to a carotid endarterectomy. The strength of the findings in terms of stroke risk reduction justifies the limited definition in this context. Thrombotic, hypoperfusion, or arterioarterial (carotid origin) unihemispheric strokes ipsilateral to an untreated 80% or greater carotid stenosis or endarterectomy would, by the working definition, be scored correctly as carotid type. An arterioarterial (aortic origin) or cardioarterial embolus could be scored incorrectly as carotid type and unfairly bias the CEA results. Hypoperfusion strokes resulting from isolated or multiple extracranial or intracranial stenoses in concert with the variations in the circle of Willis or other collaterals can lead to stroke patterns that defy attribution of a specific cause. The limits of the definition are recognized. The absence of ipsilateral stroke in the 114 CEA patients demonstrates its efficacy. Chance and epiaortic echocardiographically-guided aortic manipulation contributed to the absence of atheroembolic and other types of strokes ipsilateral to the treated carotid artery disease in these 114 patients. The high risk of stroke, about 17%, in the 50% to 80% carotid stenosis group begs the questions whether and to what degree carotid artery disease played a role and whether these patients would benefit from more liberal criteria for arteriography and endarterectomy. Most of these suggestions about treatment of carotid artery disease in the setting of coronary artery bypass are in concordance with the Guidelines for Carotid Endarterectomy: A Multidisciplinary Consensus Statement from the Ad Hoc Committee, American Heart Association [20]. Carotid endarterectomy for high-grade stenosis coincident with cardiac operation can be associated with a low risk for short- and long-term neurologic sequelae with proper teamwork [14]. Carotid endarterectomy done before or concomitant with coronary bypass has a low mortality rate, less than 4%, and reduces early postoperative stroke to less than 4% with a 10-year freedom from stroke of 88% to 96% [14]. A special interest in this problem and careful collaboration between the carotid artery and cardiac surgical teams are keys to desirable results. Stroke and mortality rates after carotid endarterectomy are strongly related to institutional volume [16, 17]. The success of this strategy is predicated on assembling a team that can achieve excellent immediate carotid and cardiac surgical results [16, 17, 21]. Important concurrent carotid artery disease should be suspected in cardiac surgical patients, especially the aged. An aggressive, formalized system of screening should be organized at the institutional or team level.

7 856 GOTT ET AL Ann Thorac Surg CAROTID/CARDIAC OPERATIONS 1999;68:850 7 When found, carotid artery disease should be treated surgically and contemporaneously. This strategy reduces short-term risk of treatment of either disease alone and enhances long-term quality and length of life for the patient with generalized atherosclerosis. We are grateful for the expertise of the Crawford Long Hospital Vascular Laboratory team, which was orchestrated by Charlene B. Willis, RN. We thank Sandra M. Ruffing, MEd and Jean B. Walker, RRA, for diligence in data collection, and Lisa D. Satterwhite for superb secretarial support. References 1. Roach GW, Kanchuger M, Mora Mangano C, et al. Adverse cerebral outcomes after coronary bypass surgery. N Engl J Med 1996;335: Berens ES, Kouchoukos NT, Murphy SF, et al. Preoperative carotid artery screening in elderly patients undergoing cardiac surgery. J Vasc Surg 1992;15: Faggioli GL, Curl GR, Ricotta JJ. The role of carotid screening before coronary bypass. J Vasc Surg 1990;12: Wareing TH, Davila-Roman VG, Daily BB, et al. Strategy for the reduction of stroke incidence in cardiac surgical patients. Ann Thorac Surg 1993;55: Salasidis GC, Latter DA, Steinmetz OK, Blair JF, Graham AM. Carotid artery duplex scanning in preoperative assessment for coronary artery revascularization: the association between peripheral vascular disease, carotid artery stenosis, and stroke. J Vasc Surg 1995;21: Schwartz LB, Bridgman AH, Kieffer RW, et al. Asymptomatic carotid artery stenosis and stroke in patients undergoing cardiopulmonary bypass. J Vasc Surg 1995;21: Sauve JS, Thorpe KE, Sackett DL, et al. Can bruits distinguish high-grade from moderate symptomatic carotid stenosis? Ann Intern Med 1994;120: North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med 1991;325: Tuman KJ, McCarthy RJ, Najafi H, Ivanovich AD. Differential effects of advanced age on neurologic and cardiac risks of coronary bypass. J Thorac Cardiovasc Surg 1992;104: D Agostino RS, Svennson LG, Neumann DJ, Balkhy HH, Williamson WA, Shahian DM. Screening carotid ultrasonography and risk factors for stroke in coronary artery surgery patients. Ann Thorac Surg 1996;62: Rizzo RJ, Whittemore AD, Couper GS, et al. Combined carotid and coronary revascularization: the preferred approach to the severe vasculopathy. Ann Thorac Surg 1992; 54: Brener BJ, Brief DK, Alpert J, et al. A four-year experience with preoperative noninvasive carotid evaluation of two thousand twenty-six patients undergoing cardiac surgery. J Vasc Surg 1984;1: Ricotta JJ. The role of carotid screening before coronary bypass. J Vasc Surg 1990;12: Akins CW, Moncure AC, Daggett WM, et al. Safety and efficacy of concomitant carotid and coronary artery operations. Ann Thorac Surg 1995;60: Vermeulen FE, Hamerlijnck RP, Defauw JJ, Ernst SM. Synchronous operation for ischemic cardiac and cerebrovascular disease: early results and long-term follow-up. Ann Thorac Surg 1992;53: Cebul RD, Snow RJ, Pine E, et al. Indications, outcomes, and provider volumes of carotid endarterectomy. JAMA 1998; 279: Wennberg DE, Lucas FL, Birkmeyer JD, et al. Variation in carotid endarterectomy mortality in the Medicare population. JAMA 1998;279: Coyle KA, Gray BC, Smith RB III, et al. Morbidity and mortality associated with carotid endarterectomy: effect of adjunctive coronary revascularization. Ann Vasc Surg 1995; 9: Hertzer NR, Loop FD, Beven BG, et al. Surgical staging for simultaneous coronary and carotid disease: a study including prospective randomization. J Vasc Surg 1989;9: Moore WS, Barnett HJ, Beebe HG, et al. Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the Ad Hoc Committee, American Heart Association [Review]. Stroke 1995;26: Moore WS, Vescara CL, Robertson JT, et al. Selection process for surgeons in the Asymptomatic Carotid Atherosclerosis Study. Stroke 1991;22: Kaste N, Fogelholm R, Rissanen A. Economic burden of stroke and the evaluation of new therapies. Public Health 1998;112: Jorgensen HS, Nakayama H, Raaschou JO, Olsen TS. Acute stroke care and rehabilitation: an analysis of the direct cost and its clinical and social determinants. The Copenhagen Stroke Study. Stroke 1997;28: Appendix The long-term charges for care of a typical stroke patient, not necessarily related to cardiac operation, range from $90,000 to $228,000 [22, 23]. The patient with a stroke after cardiac operation has a short-term expense of five to ten times the hospital charge for intermediate and rehabilitative care [1]. This expense can be $150,000 to $300,000. Applying these numbers to this patient population in a speculative and informal fashion with some assumptions, it appears that detection and prophylactic treatment make sense economically. By applying the expected range of risk for perioperative stroke (15% to 42%) to the 114 carotid and cardiac operative patients (patients with greater than 80% stenosis), 17 to 48 strokes of any type would be expected. There were actually four (no carotid type). Assuming the difference represents patients spared short-term carotid stroke by detection and prophylactic endarterectomy, then 13 to 37 times the short-term charges for outpatient hospital care of $150,000 to $300,000, or $1.95 million to $11.1 million, represents the range of potential short-term savings to the health care system. The additional hospital charges associated with screening were $889,678, substantially more than the nonrecurring actual cost of the duplex hardware of $160,000 and technician compensation of $18,000 per year. The difference in mean hospital charges for all cardiac surgical patient stays during this period ($39,309) and the mean charges for carotid and cardiac admissions ($53,018) endarterectomy multiplied by 114 patients represents a charge for prophylactic treatment of $1.56 million. In the short term, the worst case economically is a wash and the best case is a substantial savings for aggressive detection and prophylactic treatment. DISCUSSION DR KEVIN D. ACCOLA (Orlando, FL): Doctor Gott, I enjoyed your presentation, and I have a couple of questions. Regarding your algorithm in choosing which patients proceed to angiography, do you consider the importance of bilateral