Perioperative
Stroke Risk in 173 Consecutive Patients With a Past History of Stroke Jeffrey Landercasper, MD; Barbara J. Merz, MD; Thomas H. Cogbill, MD; Pamela J. Strutt, RN; Richard H. Cochrane, MD; Richard A. Olson, MD; Richard D. Hutter, MD \s=b\ During an 8-year period ending in 1988, 173 consecutive patients with a history of previous cerebrovascular accident underwent general anesthesia for surgery. Five patients (2.9%) had documented postoperative cerebrovascular accidents from 3 to 21 days (mean, 12.2 days) after surgery. The risk of postoper-
ative cerebrovascular accident did not correlate with age, sex, history of multiple cerebrovascular accidents, poststroke transient ischemic attacks, American Society for Anesthesia physical status, aspirin use, coronary artery disease, peripheral vascular disease, intraoperative blood pressure, time since previous cerebrovascular accident, or cause of previous cerebrovascular accident. Postoperative stroke was more common in patients given preoperative heparin sodium. We conclude that the risk of perioperative stroke is low (2.9%) but not easily predicted and that the risk continues beyond the first week of convalescence. Unlike myocardial infarction, cerebral reinfarction risk does not seem to depend on time since previous infarct.
(Arch Surg. 1990;125:986-989)
Stroke
is the third leading cause of death in the United States, despite the decline in stroke mortality during the last 30 years.1 The profound disability seen in stroke survi¬ vors and the financial burden accrued by society are world¬ wide problems.2 Up to 85% of patients survive a first episode of stroke and remain at risk for future cerebrovascular com¬ plications.34 Thirty-eight percent to 85% of survivors are still alive 5 years after the first cerebrovascular accident (CVA).2,4,5 This sizable international population of elderly stroke survivors is at risk for other diseases that may require surgery. Although the overall risk of postoperative stroke is less than 1% for all patients undergoing surgery,6 the risk for the population of survivors of previous stroke has not been well defined, to our knowledge. The specific impact of general anesthesia and surgery as risk factors for the occurrence of a second stroke is unknown. To examine further the precipitat¬ ing factors and relative risk of cerebral infarction associated with surgery, our experience with a select group of patients, all of whom had a medical history of stroke and then under¬ went general anesthesia, was reviewed. PATIENTS AND METHODS All patients at Gundersen/Lutheran Medical Center, La Crosse, Wis, with a documented medical history of stroke who underwent subsequent general anesthesia and surgery during the 8-year period ending in 1988 were studied by retrospective chart review. Patients undergoing cardiovascular, cerebrovascular, and neurosurgical pro¬ cedures were excluded. To estimate the postoperative stroke rate for a control population of patients who had no history of stroke, a computerized chart review was performed to compare all patients who underwent general anesthesia during the year 1982 with those
Accepted for publication May 11,1990.
From the Departments of General and Vascular Surgery (Drs Landercasper, Merz, Cogbill, and Cochrane, and Ms Strutt), Anesthesiology (Dr Olson), and Neurology (Dr Hutter), Gundersen/Lutheran Medical Center, La Crosse, Wis. Read before the 97th Annual Meeting of the Western Surgical Association, St Louis, Mo, November 14,1989. Reprint requests to the Department of Surgery, Gundersen Clinic Ltd, 1836 South Ave, La Crosse, WI 54601 (Dr Landercasper).
patients discharged in 1982 with a diagnosis of stroke. Documentation of past stroke, type of stroke, risk factors for stroke, and medications was detailed. Stroke was classified as embolie, thrombotic, hemorrhagic, traumatic, or unknown. Causes of past stroke, time from stroke to surgery, presence of multiple preoperative CVAs, and poststroke transient ischemie attacks (TIAs) were recorded. Anes¬ thesia risk classification was determined according to the American Society for Anesthesia (ASA) guidelines.7 Details of intraoperative and postoperative hemodynamic and pharmacologie management were documented, and postoperative occurrence of cerebrovascular and cardiovascular events were noted. Follow-up was established by chart review to detail subsequent postdischarge CVAs, most recent clinic visit, and mortality. All data were entered into a dBASE III PLUS program (Ashton-Tate, Tbrrance, Calif) on an AST Premi¬ um/286 computer (AST Research, Irvine, Calif). A statistical com¬ parison of results was made using analysis of two proportions with an SPSS/PC Plus (SPSS Ine, Chicago, 111) standard statistical pack¬ age, or Fisher's Exact Test where appropriate. The level of confi¬ dence was defined as P«.05.
RESULTS the During 8-year period ending in December 1988, 173 consecutive patients with a history of prior CVA underwent general anesthesia for a subsequent operation. There were 109 men (63%) and 64 women (37%), whose ages ranged from 33 to 96 years (mean, 72 years). Time since the patient's most recent CVA to surgery ranged from 1.5 weeks to 537 months (mean, 68 months). Forty-two patients had a history of multi¬ ple CVAs, and 7 had documented poststroke TIAs. The causes of stroke were recorded as embolism in 30 patients, thrombotic mechanism in 28, hemorrhagic stroke in 22, previ¬ ous perioperative stroke in 4, and unknown or other in 89. In the hemorrhagic group, 1 patient had an arteriovenous mal¬ formation and 4 patients had cerebral aneurysms. Stroke sequelae resulted in 153 motor deficits, 20 sensory deficits, 35 cranial nerve manifestations, and 80 speech abnormalities in the 173 patients. Risk factors for stroke included 111 patients with hypertension, 48 with diabetes, 89 with a history of smoking, 18 with documented hyperlipidemia, 31 with posi¬ tive family histories, 30 with history of congestive heart failure, 14 with valvular heart disease, 28 with history of atrial fibrillation or flutter, 49 with peripheral vascular dis¬ ease, and 9 with prior carotid endarterectomy; 55 patients had known coronary artery disease. Sixty-eight patients were taking aspirin or other antiplatelet drugs and 21 were receiv¬ ing warfarin sodium (Coumadin). Physical status was deter¬ mined as ASA class I in no patients, as ASA class II in nine, as ASA class III in 116, as ASA class IV in 48, and as ASA class V in none. Hospital stay ranged from 1 to 80 days (mean, 15 days). Surgery was emergent in 27 of 173 patients. Proce¬ dures included 64 general surgical, 41 orthopedic, 28 urologie, 23 peripheral vascular, 5 gynecologic, 3 otolaryngologic, 1 thoracic (noncardiac), and 8 miscellaneous procedures. Four¬ teen patients received preoperative subcutaneous heparin sodium. Perioperative variables analyzed for correlation with subsequent stroke are shown in the Table. Five (2.9%) of 173 patients sustained perioperative stroke from 3 to 21 days
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Perioperative Variables and Correlation With Stroke* Predictive Variable
Age, y
No. With
No. With
Postoperative
Postoperative
CVA/Total No.
£65
1/35
>65
4/138
Sex 3/109
M
2/64
Surgical procedure
5/87
General
Other OR SBP, mm Hg < 100 for £5 min < 100 for >5 min >180for £5 min > 180 for >5 min Highest SBP in RR, mm Hg >200 £200 Lowest SBP in RR, mm Hg
0/86 3/129 2/44 4/144
1/29 0/5 5/168
£100
3/35
>100
2/138
£90
2/15
>90
3/158
History of multiple CVA Yes
2/42
No
3/113
TIA following CVA Yes
0/7
No
ASA class llorlll IV Duration from CVA to surgery,
5/146 2/125 3/48 mo
£1
1/15
>1
4/158
£6
1/33
>6
4/140
Preoperative heparin sodium Yes
3/14
No
2/159
Preoperative warfarin sodium (Coumadin) Yes
2/21
No
3/152
Preoperative aspirin Yes
1/68
No
4/105
History of hypertension Yes
3/111
No_
2/59
Diabetes
Yes_
1/48
No
4/124
Smoking
Yes_
3/89
No
2/69
History of CHF
Yes_
2/30
No
3/129
History of CAD
Perioperative Variables and Correlation With Stroke* (cont)
Yes_
2/55
No
3/107
Predictive Variable
CVA/Total No.
Peripheral vascular disease
Yes_3/49 No
.24
2/110
Cause of past CVA Embolism
1/25
Thrombosis, hemorrhage, unknown Cause of past CVA
4/148
Thrombosis, hemorrhage, unknown Cause of past CVA
4/1 45
Hemorrhage
2/22
Thrombosis, hemorrhage, unknown
3/151
Thrombosis
.87
1/28
)
.81
.06
History of carotid endarterectomy Yes
0/9
No
5/162
.83
*CVA indicates cerebrovascular accident; OR, operating room; SBP, systolic blood pressure; RR, recovery room; TIA, transient ischemie attack; ASA, American Society for Anesthesia; CHF, congestive heart failure; and CAD, coronary artery disease.
(mean, 12.2 days) after surgery. No perioperative TIAs were identified. New strokes were confirmed by both neurologic examination and computed tomography. A new CVA mecha¬ nism was believed to be hemorrhagic in 3 patients, embolie in 1 patient, and unknown in 1 patient. Three of 5 patients with postoperative stroke were dead at 1 month, 4 at 3 months, and all 5 at 1 year. Causes of death in the 3 patients who suffered postoperative stroke and who died within 1 month included multiple organ failure, sepsis, and brain death. Stroke was believed to be a major contributing factor in each of these 3 patients. Cause of death in the 2 patients who survived initial hospitalization was unknown. At a mean follow-up of 19 months, 10 additional strokes had occurred, and 58 patients had died. In contrast to this group of 173 patients, 7517 patients with no prior history of stroke underwent general anesthesia at our institution in 1982. There were no postoperative strokes ob¬ served in this population of patients, which was screened to exclude those who underwent neurosurgical, cardiovascular, and cerebrovascular operations. Five (2.9%) of the 173 study patients suffered postopera¬ tive myocardial infarction and 4 (2.3%) developed deep ve¬ nous thrombosis or pulmonary embolism. COMMENT The overall incidence of stroke ranges from 160 to more than 3000 per 100 000 population, depending on the age, sex, and geographic location of the cohort study group.8'10 Age dramatically increases stroke risk. With an increasingly el¬ derly society, surgeons will commonly encounter patients with a past history of stroke with other conditions requiring operative intervention. The consideration of surgery in an elderly patient mandates a careful appraisal of risks and benefits. Risk assessment in patients with prior stroke in¬ cludes determination of the probability that the hemodynamic and metabolic stresses of surgery and anesthesia will lead to new cerebrovascular and cardiovascular morbidity and
mortality. In our study of 173 consecutive patients with a past history of stroke undergoing general anesthesia, the cerebral reinfarction rate was 2.9%. General state of health and severity of illness as measured by ASA classification had no significant
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( = ) influence on outcome. Age, sex, diabetes, coronary artery disease, peripheral vascular disease, prior history of multiple CVAs, and poststroke TIAs also had no further
predictive value in identifying those patients at higher risk of sustaining a perioperative stroke. Cerebral blood flow was not measured in our retrospective review, but one determi¬ nant of flow—intraoperative arterial blood pressure—was not found to be predictive. Correlation of these aforemen¬ tioned variables with subsequent stroke is statistically limit¬ ed because of the low prevalence of observed strokes in this series. A much larger patient population would need to be studied to state with a high degree of certainty that they have no influence on neurologic outcome. Systolic hypotension in the recovery room did show a statistically significant associa¬ tion (P .01) with later occurrence of postoperative stroke. The cause of the three strokes in patients with recovery room hypotension, however, was hemorrhagic in two patients and unknown in one patient. It is therefore doubtful that postop¬ erative stroke was causally related to recovery room hypo¬ tension because the two events were separated by at least 3 days, and the mechanism of stroke was not found to be isch¬ emie or thrombotic. Elapsed time from the patient's last stroke to subsequent surgery also bore no relationship to the =
risk of cerebral reinfarction. This lack of increased risk with short time from stroke to surgery differs from published reports on myocardial infarction.u"13 The risk of another cardi¬ ac event is high when general anesthesia and surgery are undertaken soon after myocardial infarction, and the risk remains elevated for 6 months. Although we observed no increased stroke risk in our group of patients undergoing operations within 1 month or 6 months following prior stroke (Table), the number of patients studied is still small. A recom¬ mendation to delay elective surgery for 1 to 3 months after stroke still seems prudent. One preoperative factor was associated with subsequent CVA. Preoperative heparin use showed a statistically signifi¬ cant correlation with postoperative stroke. Two such patients had a prior history of atrial fibrillation and probable embolie stroke. Warfarin therapy was discontinued in the immediate preoperative period, and anticoagulation continued with intervenous heparin in one patient and subcutaneous heparin in the other. The patient receiving subcutaneous heparin suf¬ fered a probable embolie stroke postoperatively. The patient receiving intravenous heparin developed an intracerebral he¬ matoma. A third patient was inappropriately given subcuta¬ neous heparin before emergency abdominal surgery that was required during the convalescent period due to subarachnoid hemorrhage; new subarachnoid hemorrhage occurred 3 days later. Preoperative use of aspirin did not correlate with subse¬ quent stroke. No other perioperative variable was associated with CVA, except type of surgery. All patients with a new postoperative stroke had undergone general or vascular sur¬ gery. No patient undergoing orthopedic, urologie, gynecolog¬ ic, or other operations suffered a postoperative stroke. Mortality after postoperative stroke was high. Three of the five patients were dead by 1 month, four by 3 months, and all by 1 year. This 60% mortality at 30 days is higher than the overall mortality for the first occurrence of stroke, which ranges from 15% to 46%.3,4 All patients dying within 1 year also contrasts sharply with the natural history of stroke survi¬ vors.2,4,5 In the Framingham study, Sacco et al4 reported a 30day mortality as low as 15% depending on the causes of the stroke. Five-year survival was 85% in men and 70% in wom¬ en, if they had no severe hypertensive or cardiac disease. In Rochester, Minn, mortality secondary to a patient's first stroke was reported to be 38%.3 In other follow-up studies, Chen and Ling2 documented a 75.5% 3-year survival in China, and Viitanen et al5 reported a 38% 5-year survival in Sweden.
Most cerebral infarctions occur many hours to days follow¬ ing intraoperative events, if patients undergoing cardiac and carotid surgery are excluded from review. No patients in our study had new stroke symptoms documented when they first awoke from general anesthesia. All were neurologically un¬ changed in the immediate postoperative period. The onset of stroke many hours following surgery raises questions about what influence general anesthesia and surgery had, if any, in precipitating stroke. A pertinent question is whether the strokes observed in our series were actually related to sur¬ gery or simply coincidental and expected from observing a population of previous stroke victims over a defined interval. If published epidemiologie data are utilized for reference and
the method of Larsen et al6 is used to calculate the chance of stroke, then the estimated number of expected strokes occur¬ ring randomly in 173 elderly patients with a past history of stroke observed for an average hospitalization period of 15 days ranges from 0.01 to O.5.8"1" It is therefore unlikely that the five postoperative strokes observed in our series were ran¬ dom occurrences. No strokes were observed at our institution in a control population of more than 7000 patients who had no past history of stroke and then underwent general anesthesia for operations not involving the brain, carotid arteries, or cardiopulmonary bypass. Our finding of perioperative strokes occurring in the postoperative convalescent period has been reported by others.14 Hart and Hindman" described the hospital course of 12 patients with perioperative stroke, 10 (83%) of whom sustained a stroke late in the postoperative period, only two of which were believed to have occurred intraoperatively. Postoperative stroke risk after general and vascular surgery ranges from 0.2% to 0.7%.6,12,15"17 All five observed strokes in our study occurred after 87 general and vascular surgical procedures, an increase in stroke risk com¬ pared with that reported in studies that did not stratify patients who had a past history of stroke. This higher risk is in agreement with that reported in previous reports of patients with a known cerebrovascular history who were observed. Knapp et al15 examined 8984 male surgical patients older than 50 years. Sixty-nine had a previous history of CVA, 1 (1.5%) of whom suffered a new postoperative CVA. In a prospective study from Denmark that detailed postoperative complica¬ tions in 2463 patients, 6 (2.1%) of 279 patients with a history of any type of preoperative cerebrovascular disease sustained a postoperative CVA.6 This stroke risk is comparable with that of patients with known peripheral vascular disease. Turnipseed et al18 documented that 4.8% of 330 patients undergoing vascular surgery developed stroke. The risk of stroke associ¬ ated with surgery is still low in these patient populations selected for known cerebrovascular or operative peripheral vascular disease but seems to be higher than in reports of patients with asymptomatic carotid bruits. Ropper et al17 studied 735 patients with carotid bruits and reported that postoperative stroke occurred in less than 1%. Causes of the five postoperative strokes in our study includ¬ ed hemorrhagic infarction in three patients and probable embolie infarction in one patient with atrial fibrillation; the cause was unknown in the remaining patient. Only two of the five patients had similar known mechanisms of the first stroke and the new postoperative stroke. One patient was admitted to the hospital with a subarachnoid hemorrhage requiring emergent laparotomy 9 days later for a perforated gastric ulcer. Further subarachnoid hemorrhage developed 3 days postoperatively. In another patient with known atrial fibrilla¬ tion and a history of stroke, warfarin anticoagulation therapy was discontinued before cholecystectomy. A new stroke, probably of embolie origin, occurred postoperatively and the patient underwent subsequent anticoagulation. In another review of 12 postoperative strokes, Hart and Hindman14 de-
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scribed six patients with embolie mechanisms, one with a thrombotic mechanism, two with stroke related to hypoten¬ sion, and three with unknown mechanisms. Only two of Hart and Hindman's patients had a history of preoperative cere¬ brovascular disease or stroke. To our knowledge, there are few other reported cases in which the mechanisms of prior stroke have been compared with new perioperative strokes. From the few data available, it appears that the causes of postoperative stroke are variable and that they may be differ¬ ent from prior stroke. This is in contrast to the Framingham study, which suggested that recurrent strokes were usually caused by the same mechanism.4 Five additional patients also developed postoperative myo¬ cardial infarction, a reflection of the widespread vascular disease present in patients with a past history of stroke. As Cooperman et al16 have suggested, the preoperative finding of cerebrovascular disease is another risk factor for postopera¬ tive myocardial infarction. They studied cardiovascular risk factors in 566 patients undergoing major vascular surgery. Prior CVA was one of five independent risk factors that showed a significant association with postoperative cardiac
complications.
In summary,
patients with
a
past history of stroke who
undergo surgery have a low risk of new cerebral infarction.
Although the total number of such patients studied was still small, surgery appears to be safe, even if performed soon after a stroke. Preoperative heparin use was associated with increased risk of postoperative stroke. Unfortunately, there appear to be few standard measurable intraoperative influ¬ ences on the subsequent evolution of perioperative stroke in
noncarotid and noncardiac surgery. General anesthesia and surgery may cause unknown perturbations of cerebral autoregulation, cerebral blood flow, metabolic demand, and coag¬ ulation that persists for days and weeks, increasing the likeli¬ hood of stroke. Known precautions to prevent stroke include avoidance of hypotension in patients with known carotid oc¬ clusive disease and aggressive treatment of intraoperative hypertension in patients with a past history of hemorrhagic stroke or subarachnoid bleeding. Adherence to these princi¬ ples, however, does not guarantee elimination of stroke risk, because mechanisms of prior and postoperative stroke may differ. Furthermore, the risk of postoperative CVA continues late into the convalescent period, when aggressive patient monitoring of blood pressure, coagulation status, and oxygén¬ ation is no longer routinely performed. This study was supported in part by the R. James Trane Surgical Research and Data Center/Gundersen Medical Foundation Ltd. The authors thank Kathy Sandy for manuscript preparation.
References 1. Hospital discharge rates for cerebrovascular disease\p=m-\UnitedStates, 1970-1986. MMWR. 1989;38:194-201. 2. Chen Q, Ling R. A 1-4 year follow-up study of 306 cases of stroke. Stroke.
1982;13:290-295.
3. Matsumoto N, Whisnant JP, Kurland LT, Okazaki H. Natural history of stroke in Rochester, Minnesota 1955 through 1969: an extension of a previous study, 1945 through 1954. Stroke. 1973;4:20-29. 4. Sacco RL, Wolf PA, Kannel WB, McNamara PM. Survival and recurrence following stroke. Stroke. 1982;13:290-295. 5. Viitanen M, Eriksson S, Asplund K. Risk of recurrent stroke, myocardial infarction and epilepsy during long-term follow-up after stroke. Eur Neurol.
1988;28:227-231. 6. Larsen SF, Zaric D, Boysen G. Postoperative cerebrovascular accidents in general surgery. Acta Anaesthesiol Scand. 1988;32:698-701. 7. Schneider AJL. Assessment of risk factors and surgical outcome. Surg Clin North Am. 1983;63:1113-1126. 8. Robins M, Baum HM. Incidence of stroke. Stroke. 1981;12(suppl 1):45-55. 9. Hansen BS, Marquardsen J. Incidence of stroke in Frederiksberg, Denmark. Stroke. 1977;8:663-665.
10. Schroll M. A ten-year prospective study, 1964-1974, of cardiovascular risk factors in men and women from the Glostrup population born in 1914. Dan Med Bull. 1982;29:213-251. 11. Steen PA, Tinker JH, Tarhan S. Myocardial infarction after anesthesia and surgery. JAMA. 1978;239;2566-2570. 12. Goldman L, Caldera DL, Southwick FS, et al. Cardiac risk factors and complications in non-cardiac surgery. Medicine (Baltimore). 1978;57:357-370. 13. Rao TLK, Jacobs KH, El-Etr AA. Reinfarction following anesthesia in patients with myocardial infarction. Anesthesiology. 1983;58:499-505. 14. Hart R, Hindman B. Mechanisms of perioperative cerebral infarction. Stroke. 1982;13:766-772. 15. Knapp RB, Topkins MJ, Artusio JF. The cerebrovascular accident and coronary occlusion in anesthesia. JAMA. 1962;182:332-334. 16. Cooperman M, Pflug B, Martin EW, Evans WE. Cardiovascular risk factors in patients with peripheral vascular disease. Surgery. 1978;84:505-509. 17. Ropper AH, Wechsler LR, Wilson LS. Carotid bruit and the risk of stroke in elective surgery. N Engl J Med. 1982;307:1388-1390. 18. Turnipseed WD, Berkoff HA, Belzer FO. Postoperative stroke in cardiac and peripheral vascular disease. Ann Surg. 1980;192:365-368.
Discussion GEORGE E. PIERCE, MD, Kansas City, Kan: Dr Landercasper and his associates have addressed an important and interesting question: Does the history of a previous stroke constitute a risk factor for postoperative stroke following noncardiac, noncerebrovascular pro¬ cedures performed under general anesthesia? The answer appears to be yes. The 2.9% incidence of postoperative stroke is 5 to 10 times higher than the incidence reported in the literature for the general population in this age group, although it would have been of interest to know the incidence of postoperative stroke in a control group of patients at the Gundersen Clinic who had no history of stroke and who were operated on during the same period of this study. Although a history of stroke appears to be a risk factor for postop¬ erative stroke, we cannot determine whether it is an independent risk factor because all of the patients in this study had a history of stroke. Also, because there were only five postoperative strokes in this series and because there are many different mechanisms for stroke, it is difficult to draw conclusions concerning the presence or absence of a relationship between the initial stroke and the postoperative stroke and difficult to draw conclusions about other factors that might influence the incidence of postoperative stroke. Fortunately there was not, but if there had been a much larger number of postoperative strokes, Landercasper et al might have found some correlation between stroke and such factors as coronary artery disease, diabetes, and hypertension. Regardless of these considerations, this important report empha¬ sizes that patients with a history of stroke are at increased risk for serious postoperative complications. Not only was the stroke rate
nearly 3% but these strokes were associated with a high mortality. Furthermore, the rate of postoperative myocardial infarction was also 2.9%, for a combined stroke/myocardial infarction rate of nearly
6%. Because cerebrovascular disease appears to be a marker for coro¬ nary artery disease, as suggested not only by this study but by a number of other studies, do the authors have any special recommen¬ dations for preoperative cardiac evaluation and perioperative cardiac management of patients with a history of stroke? It is of special interest that only one stroke occurred in 33 patients who underwent operation within 6 months following a stroke. I agree with the authors, however, that, regardless of this observation, most of us would be reluctant to recommend purely elective operations within the first 1 to 2 months after a stroke. Dr LANDERCASPER: I thank Dr Pierce for his comments. I do not know the incidence of stroke in the Gundersen Clinic for those pa¬ tients who were not part of this study. To find 173 consecutive patients in our clinic who had a medical history of stroke, we had to review the discharge diagnoses of about 80 000 patients undergoing surgery during that same 8-year period. Our recommendation for preoperative cardiac evaluation in these patients is similar to our recommendation for those patients with peripheral vascular disease—a careful history and a good physical examination; we also often perform noninvasive treadmill testing in patients with asymptomatic peripheral vascular disease. More inva¬ sive testing is recommended for those with symptoms or electrocardiographic evidence of substantial coronary artery disease.
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Stroke Risk in 173 Consecutive Patients With a Past History of Stroke Jeffrey Landercasper, MD; Barbara J. Merz, MD; Thomas H. Cogbill, MD; Pamela J. Strutt, RN; Richard H. Cochrane, MD; Richard A. Olson, MD; Richard D. Hutter, MD \s=b\ During an 8-year period ending in 1988, 173 consecutive patients with a history of previous cerebrovascular accident underwent general anesthesia for surgery. Five patients (2.9%) had documented postoperative cerebrovascular accidents from 3 to 21 days (mean, 12.2 days) after surgery. The risk of postoper-
ative cerebrovascular accident did not correlate with age, sex, history of multiple cerebrovascular accidents, poststroke transient ischemic attacks, American Society for Anesthesia physical status, aspirin use, coronary artery disease, peripheral vascular disease, intraoperative blood pressure, time since previous cerebrovascular accident, or cause of previous cerebrovascular accident. Postoperative stroke was more common in patients given preoperative heparin sodium. We conclude that the risk of perioperative stroke is low (2.9%) but not easily predicted and that the risk continues beyond the first week of convalescence. Unlike myocardial infarction, cerebral reinfarction risk does not seem to depend on time since previous infarct.
(Arch Surg. 1990;125:986-989)
Stroke
is the third leading cause of death in the United States, despite the decline in stroke mortality during the last 30 years.1 The profound disability seen in stroke survi¬ vors and the financial burden accrued by society are world¬ wide problems.2 Up to 85% of patients survive a first episode of stroke and remain at risk for future cerebrovascular com¬ plications.34 Thirty-eight percent to 85% of survivors are still alive 5 years after the first cerebrovascular accident (CVA).2,4,5 This sizable international population of elderly stroke survivors is at risk for other diseases that may require surgery. Although the overall risk of postoperative stroke is less than 1% for all patients undergoing surgery,6 the risk for the population of survivors of previous stroke has not been well defined, to our knowledge. The specific impact of general anesthesia and surgery as risk factors for the occurrence of a second stroke is unknown. To examine further the precipitat¬ ing factors and relative risk of cerebral infarction associated with surgery, our experience with a select group of patients, all of whom had a medical history of stroke and then under¬ went general anesthesia, was reviewed. PATIENTS AND METHODS All patients at Gundersen/Lutheran Medical Center, La Crosse, Wis, with a documented medical history of stroke who underwent subsequent general anesthesia and surgery during the 8-year period ending in 1988 were studied by retrospective chart review. Patients undergoing cardiovascular, cerebrovascular, and neurosurgical pro¬ cedures were excluded. To estimate the postoperative stroke rate for a control population of patients who had no history of stroke, a computerized chart review was performed to compare all patients who underwent general anesthesia during the year 1982 with those
Accepted for publication May 11,1990.
From the Departments of General and Vascular Surgery (Drs Landercasper, Merz, Cogbill, and Cochrane, and Ms Strutt), Anesthesiology (Dr Olson), and Neurology (Dr Hutter), Gundersen/Lutheran Medical Center, La Crosse, Wis. Read before the 97th Annual Meeting of the Western Surgical Association, St Louis, Mo, November 14,1989. Reprint requests to the Department of Surgery, Gundersen Clinic Ltd, 1836 South Ave, La Crosse, WI 54601 (Dr Landercasper).
patients discharged in 1982 with a diagnosis of stroke. Documentation of past stroke, type of stroke, risk factors for stroke, and medications was detailed. Stroke was classified as embolie, thrombotic, hemorrhagic, traumatic, or unknown. Causes of past stroke, time from stroke to surgery, presence of multiple preoperative CVAs, and poststroke transient ischemie attacks (TIAs) were recorded. Anes¬ thesia risk classification was determined according to the American Society for Anesthesia (ASA) guidelines.7 Details of intraoperative and postoperative hemodynamic and pharmacologie management were documented, and postoperative occurrence of cerebrovascular and cardiovascular events were noted. Follow-up was established by chart review to detail subsequent postdischarge CVAs, most recent clinic visit, and mortality. All data were entered into a dBASE III PLUS program (Ashton-Tate, Tbrrance, Calif) on an AST Premi¬ um/286 computer (AST Research, Irvine, Calif). A statistical com¬ parison of results was made using analysis of two proportions with an SPSS/PC Plus (SPSS Ine, Chicago, 111) standard statistical pack¬ age, or Fisher's Exact Test where appropriate. The level of confi¬ dence was defined as P«.05.
RESULTS the During 8-year period ending in December 1988, 173 consecutive patients with a history of prior CVA underwent general anesthesia for a subsequent operation. There were 109 men (63%) and 64 women (37%), whose ages ranged from 33 to 96 years (mean, 72 years). Time since the patient's most recent CVA to surgery ranged from 1.5 weeks to 537 months (mean, 68 months). Forty-two patients had a history of multi¬ ple CVAs, and 7 had documented poststroke TIAs. The causes of stroke were recorded as embolism in 30 patients, thrombotic mechanism in 28, hemorrhagic stroke in 22, previ¬ ous perioperative stroke in 4, and unknown or other in 89. In the hemorrhagic group, 1 patient had an arteriovenous mal¬ formation and 4 patients had cerebral aneurysms. Stroke sequelae resulted in 153 motor deficits, 20 sensory deficits, 35 cranial nerve manifestations, and 80 speech abnormalities in the 173 patients. Risk factors for stroke included 111 patients with hypertension, 48 with diabetes, 89 with a history of smoking, 18 with documented hyperlipidemia, 31 with posi¬ tive family histories, 30 with history of congestive heart failure, 14 with valvular heart disease, 28 with history of atrial fibrillation or flutter, 49 with peripheral vascular dis¬ ease, and 9 with prior carotid endarterectomy; 55 patients had known coronary artery disease. Sixty-eight patients were taking aspirin or other antiplatelet drugs and 21 were receiv¬ ing warfarin sodium (Coumadin). Physical status was deter¬ mined as ASA class I in no patients, as ASA class II in nine, as ASA class III in 116, as ASA class IV in 48, and as ASA class V in none. Hospital stay ranged from 1 to 80 days (mean, 15 days). Surgery was emergent in 27 of 173 patients. Proce¬ dures included 64 general surgical, 41 orthopedic, 28 urologie, 23 peripheral vascular, 5 gynecologic, 3 otolaryngologic, 1 thoracic (noncardiac), and 8 miscellaneous procedures. Four¬ teen patients received preoperative subcutaneous heparin sodium. Perioperative variables analyzed for correlation with subsequent stroke are shown in the Table. Five (2.9%) of 173 patients sustained perioperative stroke from 3 to 21 days
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Perioperative Variables and Correlation With Stroke* Predictive Variable
Age, y
No. With
No. With
Postoperative
Postoperative
CVA/Total No.
£65
1/35
>65
4/138
Sex 3/109
M
2/64
Surgical procedure
5/87
General
Other OR SBP, mm Hg < 100 for £5 min < 100 for >5 min >180for £5 min > 180 for >5 min Highest SBP in RR, mm Hg >200 £200 Lowest SBP in RR, mm Hg
0/86 3/129 2/44 4/144
1/29 0/5 5/168
£100
3/35
>100
2/138
£90
2/15
>90
3/158
History of multiple CVA Yes
2/42
No
3/113
TIA following CVA Yes
0/7
No
ASA class llorlll IV Duration from CVA to surgery,
5/146 2/125 3/48 mo
£1
1/15
>1
4/158
£6
1/33
>6
4/140
Preoperative heparin sodium Yes
3/14
No
2/159
Preoperative warfarin sodium (Coumadin) Yes
2/21
No
3/152
Preoperative aspirin Yes
1/68
No
4/105
History of hypertension Yes
3/111
No_
2/59
Diabetes
Yes_
1/48
No
4/124
Smoking
Yes_
3/89
No
2/69
History of CHF
Yes_
2/30
No
3/129
History of CAD
Perioperative Variables and Correlation With Stroke* (cont)
Yes_
2/55
No
3/107
Predictive Variable
CVA/Total No.
Peripheral vascular disease
Yes_3/49 No
.24
2/110
Cause of past CVA Embolism
1/25
Thrombosis, hemorrhage, unknown Cause of past CVA
4/148
Thrombosis, hemorrhage, unknown Cause of past CVA
4/1 45
Hemorrhage
2/22
Thrombosis, hemorrhage, unknown
3/151
Thrombosis
.87
1/28
)
.81
.06
History of carotid endarterectomy Yes
0/9
No
5/162
.83
*CVA indicates cerebrovascular accident; OR, operating room; SBP, systolic blood pressure; RR, recovery room; TIA, transient ischemie attack; ASA, American Society for Anesthesia; CHF, congestive heart failure; and CAD, coronary artery disease.
(mean, 12.2 days) after surgery. No perioperative TIAs were identified. New strokes were confirmed by both neurologic examination and computed tomography. A new CVA mecha¬ nism was believed to be hemorrhagic in 3 patients, embolie in 1 patient, and unknown in 1 patient. Three of 5 patients with postoperative stroke were dead at 1 month, 4 at 3 months, and all 5 at 1 year. Causes of death in the 3 patients who suffered postoperative stroke and who died within 1 month included multiple organ failure, sepsis, and brain death. Stroke was believed to be a major contributing factor in each of these 3 patients. Cause of death in the 2 patients who survived initial hospitalization was unknown. At a mean follow-up of 19 months, 10 additional strokes had occurred, and 58 patients had died. In contrast to this group of 173 patients, 7517 patients with no prior history of stroke underwent general anesthesia at our institution in 1982. There were no postoperative strokes ob¬ served in this population of patients, which was screened to exclude those who underwent neurosurgical, cardiovascular, and cerebrovascular operations. Five (2.9%) of the 173 study patients suffered postopera¬ tive myocardial infarction and 4 (2.3%) developed deep ve¬ nous thrombosis or pulmonary embolism. COMMENT The overall incidence of stroke ranges from 160 to more than 3000 per 100 000 population, depending on the age, sex, and geographic location of the cohort study group.8'10 Age dramatically increases stroke risk. With an increasingly el¬ derly society, surgeons will commonly encounter patients with a past history of stroke with other conditions requiring operative intervention. The consideration of surgery in an elderly patient mandates a careful appraisal of risks and benefits. Risk assessment in patients with prior stroke in¬ cludes determination of the probability that the hemodynamic and metabolic stresses of surgery and anesthesia will lead to new cerebrovascular and cardiovascular morbidity and
mortality. In our study of 173 consecutive patients with a past history of stroke undergoing general anesthesia, the cerebral reinfarction rate was 2.9%. General state of health and severity of illness as measured by ASA classification had no significant
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( = ) influence on outcome. Age, sex, diabetes, coronary artery disease, peripheral vascular disease, prior history of multiple CVAs, and poststroke TIAs also had no further
predictive value in identifying those patients at higher risk of sustaining a perioperative stroke. Cerebral blood flow was not measured in our retrospective review, but one determi¬ nant of flow—intraoperative arterial blood pressure—was not found to be predictive. Correlation of these aforemen¬ tioned variables with subsequent stroke is statistically limit¬ ed because of the low prevalence of observed strokes in this series. A much larger patient population would need to be studied to state with a high degree of certainty that they have no influence on neurologic outcome. Systolic hypotension in the recovery room did show a statistically significant associa¬ tion (P .01) with later occurrence of postoperative stroke. The cause of the three strokes in patients with recovery room hypotension, however, was hemorrhagic in two patients and unknown in one patient. It is therefore doubtful that postop¬ erative stroke was causally related to recovery room hypo¬ tension because the two events were separated by at least 3 days, and the mechanism of stroke was not found to be isch¬ emie or thrombotic. Elapsed time from the patient's last stroke to subsequent surgery also bore no relationship to the =
risk of cerebral reinfarction. This lack of increased risk with short time from stroke to surgery differs from published reports on myocardial infarction.u"13 The risk of another cardi¬ ac event is high when general anesthesia and surgery are undertaken soon after myocardial infarction, and the risk remains elevated for 6 months. Although we observed no increased stroke risk in our group of patients undergoing operations within 1 month or 6 months following prior stroke (Table), the number of patients studied is still small. A recom¬ mendation to delay elective surgery for 1 to 3 months after stroke still seems prudent. One preoperative factor was associated with subsequent CVA. Preoperative heparin use showed a statistically signifi¬ cant correlation with postoperative stroke. Two such patients had a prior history of atrial fibrillation and probable embolie stroke. Warfarin therapy was discontinued in the immediate preoperative period, and anticoagulation continued with intervenous heparin in one patient and subcutaneous heparin in the other. The patient receiving subcutaneous heparin suf¬ fered a probable embolie stroke postoperatively. The patient receiving intravenous heparin developed an intracerebral he¬ matoma. A third patient was inappropriately given subcuta¬ neous heparin before emergency abdominal surgery that was required during the convalescent period due to subarachnoid hemorrhage; new subarachnoid hemorrhage occurred 3 days later. Preoperative use of aspirin did not correlate with subse¬ quent stroke. No other perioperative variable was associated with CVA, except type of surgery. All patients with a new postoperative stroke had undergone general or vascular sur¬ gery. No patient undergoing orthopedic, urologie, gynecolog¬ ic, or other operations suffered a postoperative stroke. Mortality after postoperative stroke was high. Three of the five patients were dead by 1 month, four by 3 months, and all by 1 year. This 60% mortality at 30 days is higher than the overall mortality for the first occurrence of stroke, which ranges from 15% to 46%.3,4 All patients dying within 1 year also contrasts sharply with the natural history of stroke survi¬ vors.2,4,5 In the Framingham study, Sacco et al4 reported a 30day mortality as low as 15% depending on the causes of the stroke. Five-year survival was 85% in men and 70% in wom¬ en, if they had no severe hypertensive or cardiac disease. In Rochester, Minn, mortality secondary to a patient's first stroke was reported to be 38%.3 In other follow-up studies, Chen and Ling2 documented a 75.5% 3-year survival in China, and Viitanen et al5 reported a 38% 5-year survival in Sweden.
Most cerebral infarctions occur many hours to days follow¬ ing intraoperative events, if patients undergoing cardiac and carotid surgery are excluded from review. No patients in our study had new stroke symptoms documented when they first awoke from general anesthesia. All were neurologically un¬ changed in the immediate postoperative period. The onset of stroke many hours following surgery raises questions about what influence general anesthesia and surgery had, if any, in precipitating stroke. A pertinent question is whether the strokes observed in our series were actually related to sur¬ gery or simply coincidental and expected from observing a population of previous stroke victims over a defined interval. If published epidemiologie data are utilized for reference and
the method of Larsen et al6 is used to calculate the chance of stroke, then the estimated number of expected strokes occur¬ ring randomly in 173 elderly patients with a past history of stroke observed for an average hospitalization period of 15 days ranges from 0.01 to O.5.8"1" It is therefore unlikely that the five postoperative strokes observed in our series were ran¬ dom occurrences. No strokes were observed at our institution in a control population of more than 7000 patients who had no past history of stroke and then underwent general anesthesia for operations not involving the brain, carotid arteries, or cardiopulmonary bypass. Our finding of perioperative strokes occurring in the postoperative convalescent period has been reported by others.14 Hart and Hindman" described the hospital course of 12 patients with perioperative stroke, 10 (83%) of whom sustained a stroke late in the postoperative period, only two of which were believed to have occurred intraoperatively. Postoperative stroke risk after general and vascular surgery ranges from 0.2% to 0.7%.6,12,15"17 All five observed strokes in our study occurred after 87 general and vascular surgical procedures, an increase in stroke risk com¬ pared with that reported in studies that did not stratify patients who had a past history of stroke. This higher risk is in agreement with that reported in previous reports of patients with a known cerebrovascular history who were observed. Knapp et al15 examined 8984 male surgical patients older than 50 years. Sixty-nine had a previous history of CVA, 1 (1.5%) of whom suffered a new postoperative CVA. In a prospective study from Denmark that detailed postoperative complica¬ tions in 2463 patients, 6 (2.1%) of 279 patients with a history of any type of preoperative cerebrovascular disease sustained a postoperative CVA.6 This stroke risk is comparable with that of patients with known peripheral vascular disease. Turnipseed et al18 documented that 4.8% of 330 patients undergoing vascular surgery developed stroke. The risk of stroke associ¬ ated with surgery is still low in these patient populations selected for known cerebrovascular or operative peripheral vascular disease but seems to be higher than in reports of patients with asymptomatic carotid bruits. Ropper et al17 studied 735 patients with carotid bruits and reported that postoperative stroke occurred in less than 1%. Causes of the five postoperative strokes in our study includ¬ ed hemorrhagic infarction in three patients and probable embolie infarction in one patient with atrial fibrillation; the cause was unknown in the remaining patient. Only two of the five patients had similar known mechanisms of the first stroke and the new postoperative stroke. One patient was admitted to the hospital with a subarachnoid hemorrhage requiring emergent laparotomy 9 days later for a perforated gastric ulcer. Further subarachnoid hemorrhage developed 3 days postoperatively. In another patient with known atrial fibrilla¬ tion and a history of stroke, warfarin anticoagulation therapy was discontinued before cholecystectomy. A new stroke, probably of embolie origin, occurred postoperatively and the patient underwent subsequent anticoagulation. In another review of 12 postoperative strokes, Hart and Hindman14 de-
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scribed six patients with embolie mechanisms, one with a thrombotic mechanism, two with stroke related to hypoten¬ sion, and three with unknown mechanisms. Only two of Hart and Hindman's patients had a history of preoperative cere¬ brovascular disease or stroke. To our knowledge, there are few other reported cases in which the mechanisms of prior stroke have been compared with new perioperative strokes. From the few data available, it appears that the causes of postoperative stroke are variable and that they may be differ¬ ent from prior stroke. This is in contrast to the Framingham study, which suggested that recurrent strokes were usually caused by the same mechanism.4 Five additional patients also developed postoperative myo¬ cardial infarction, a reflection of the widespread vascular disease present in patients with a past history of stroke. As Cooperman et al16 have suggested, the preoperative finding of cerebrovascular disease is another risk factor for postopera¬ tive myocardial infarction. They studied cardiovascular risk factors in 566 patients undergoing major vascular surgery. Prior CVA was one of five independent risk factors that showed a significant association with postoperative cardiac
complications.
In summary,
patients with
a
past history of stroke who
undergo surgery have a low risk of new cerebral infarction.
Although the total number of such patients studied was still small, surgery appears to be safe, even if performed soon after a stroke. Preoperative heparin use was associated with increased risk of postoperative stroke. Unfortunately, there appear to be few standard measurable intraoperative influ¬ ences on the subsequent evolution of perioperative stroke in
noncarotid and noncardiac surgery. General anesthesia and surgery may cause unknown perturbations of cerebral autoregulation, cerebral blood flow, metabolic demand, and coag¬ ulation that persists for days and weeks, increasing the likeli¬ hood of stroke. Known precautions to prevent stroke include avoidance of hypotension in patients with known carotid oc¬ clusive disease and aggressive treatment of intraoperative hypertension in patients with a past history of hemorrhagic stroke or subarachnoid bleeding. Adherence to these princi¬ ples, however, does not guarantee elimination of stroke risk, because mechanisms of prior and postoperative stroke may differ. Furthermore, the risk of postoperative CVA continues late into the convalescent period, when aggressive patient monitoring of blood pressure, coagulation status, and oxygén¬ ation is no longer routinely performed. This study was supported in part by the R. James Trane Surgical Research and Data Center/Gundersen Medical Foundation Ltd. The authors thank Kathy Sandy for manuscript preparation.
References 1. Hospital discharge rates for cerebrovascular disease\p=m-\UnitedStates, 1970-1986. MMWR. 1989;38:194-201. 2. Chen Q, Ling R. A 1-4 year follow-up study of 306 cases of stroke. Stroke.
1982;13:290-295.
3. Matsumoto N, Whisnant JP, Kurland LT, Okazaki H. Natural history of stroke in Rochester, Minnesota 1955 through 1969: an extension of a previous study, 1945 through 1954. Stroke. 1973;4:20-29. 4. Sacco RL, Wolf PA, Kannel WB, McNamara PM. Survival and recurrence following stroke. Stroke. 1982;13:290-295. 5. Viitanen M, Eriksson S, Asplund K. Risk of recurrent stroke, myocardial infarction and epilepsy during long-term follow-up after stroke. Eur Neurol.
1988;28:227-231. 6. Larsen SF, Zaric D, Boysen G. Postoperative cerebrovascular accidents in general surgery. Acta Anaesthesiol Scand. 1988;32:698-701. 7. Schneider AJL. Assessment of risk factors and surgical outcome. Surg Clin North Am. 1983;63:1113-1126. 8. Robins M, Baum HM. Incidence of stroke. Stroke. 1981;12(suppl 1):45-55. 9. Hansen BS, Marquardsen J. Incidence of stroke in Frederiksberg, Denmark. Stroke. 1977;8:663-665.
10. Schroll M. A ten-year prospective study, 1964-1974, of cardiovascular risk factors in men and women from the Glostrup population born in 1914. Dan Med Bull. 1982;29:213-251. 11. Steen PA, Tinker JH, Tarhan S. Myocardial infarction after anesthesia and surgery. JAMA. 1978;239;2566-2570. 12. Goldman L, Caldera DL, Southwick FS, et al. Cardiac risk factors and complications in non-cardiac surgery. Medicine (Baltimore). 1978;57:357-370. 13. Rao TLK, Jacobs KH, El-Etr AA. Reinfarction following anesthesia in patients with myocardial infarction. Anesthesiology. 1983;58:499-505. 14. Hart R, Hindman B. Mechanisms of perioperative cerebral infarction. Stroke. 1982;13:766-772. 15. Knapp RB, Topkins MJ, Artusio JF. The cerebrovascular accident and coronary occlusion in anesthesia. JAMA. 1962;182:332-334. 16. Cooperman M, Pflug B, Martin EW, Evans WE. Cardiovascular risk factors in patients with peripheral vascular disease. Surgery. 1978;84:505-509. 17. Ropper AH, Wechsler LR, Wilson LS. Carotid bruit and the risk of stroke in elective surgery. N Engl J Med. 1982;307:1388-1390. 18. Turnipseed WD, Berkoff HA, Belzer FO. Postoperative stroke in cardiac and peripheral vascular disease. Ann Surg. 1980;192:365-368.
Discussion GEORGE E. PIERCE, MD, Kansas City, Kan: Dr Landercasper and his associates have addressed an important and interesting question: Does the history of a previous stroke constitute a risk factor for postoperative stroke following noncardiac, noncerebrovascular pro¬ cedures performed under general anesthesia? The answer appears to be yes. The 2.9% incidence of postoperative stroke is 5 to 10 times higher than the incidence reported in the literature for the general population in this age group, although it would have been of interest to know the incidence of postoperative stroke in a control group of patients at the Gundersen Clinic who had no history of stroke and who were operated on during the same period of this study. Although a history of stroke appears to be a risk factor for postop¬ erative stroke, we cannot determine whether it is an independent risk factor because all of the patients in this study had a history of stroke. Also, because there were only five postoperative strokes in this series and because there are many different mechanisms for stroke, it is difficult to draw conclusions concerning the presence or absence of a relationship between the initial stroke and the postoperative stroke and difficult to draw conclusions about other factors that might influence the incidence of postoperative stroke. Fortunately there was not, but if there had been a much larger number of postoperative strokes, Landercasper et al might have found some correlation between stroke and such factors as coronary artery disease, diabetes, and hypertension. Regardless of these considerations, this important report empha¬ sizes that patients with a history of stroke are at increased risk for serious postoperative complications. Not only was the stroke rate
nearly 3% but these strokes were associated with a high mortality. Furthermore, the rate of postoperative myocardial infarction was also 2.9%, for a combined stroke/myocardial infarction rate of nearly
6%. Because cerebrovascular disease appears to be a marker for coro¬ nary artery disease, as suggested not only by this study but by a number of other studies, do the authors have any special recommen¬ dations for preoperative cardiac evaluation and perioperative cardiac management of patients with a history of stroke? It is of special interest that only one stroke occurred in 33 patients who underwent operation within 6 months following a stroke. I agree with the authors, however, that, regardless of this observation, most of us would be reluctant to recommend purely elective operations within the first 1 to 2 months after a stroke. Dr LANDERCASPER: I thank Dr Pierce for his comments. I do not know the incidence of stroke in the Gundersen Clinic for those pa¬ tients who were not part of this study. To find 173 consecutive patients in our clinic who had a medical history of stroke, we had to review the discharge diagnoses of about 80 000 patients undergoing surgery during that same 8-year period. Our recommendation for preoperative cardiac evaluation in these patients is similar to our recommendation for those patients with peripheral vascular disease—a careful history and a good physical examination; we also often perform noninvasive treadmill testing in patients with asymptomatic peripheral vascular disease. More inva¬ sive testing is recommended for those with symptoms or electrocardiographic evidence of substantial coronary artery disease.
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