Asymptomatic Carotid Bruit

Asymptomatic Carotid Bruit:

Long-term Outcome of Patients Having Endarterectomy Compared with Unoperated Controls

JESSE E. THOMPSON, M.D., R. DON PATMAN, M.D., C. M. TALKINGTON, M.D.

During 20 years (1957-1977), 1286 carotid endarterectomies From the Department of General Surgery were performed on 1022 private patients with cerebrovascular Baylor University Medical Center, insufficiency. Included were 132 patients undergoing 167 end- Dallas, Texas arterectomies for asymptomatic cervical carotid bruits. Ages ranged from 42 to 82 years (mean: 64.7). Operative mortality was zero. There were two transient and two permanent operation-related neurologic deficits. Complete follow-up was and the incidence of subsequent strokes is markedly achieved, extending to 184 months. During postoperative fol- reduced.21'24 low-up, six patients (4.5%) developed TIA's appropriate to The most controversial area at present concerns the the unoperated artery, three patients had strokes (2.3%), and advisability of performing arteriography and operation three patients died of strokes (2.3%). To characterize the natu- on ral history of asymptomatic bruit and determine proper in- patients with asymptomatic carotid bruits. Asympto- dications for prophylactic endarterectomy, a control series matic subclavian bruits, even with a demonstrated sub- of 138 additional patients with asymptomatic bruits not op- clavian steal syndrome, do not require operative in- erated upon when the bruit was discovered was studied. Ages tervention. However, the midcarotid bruit, which re- ranged from 39 to 86 years (mean: 65.7). During follow-up flects the presence of atherosclerosis at the common extending to 180 months, 77 patients (55.8%) remained neurologically asymptomatic, 37 patients (26.8%) developed TIA's carotid bifurcation, is another matter. Ninety per cent one month to 99 months after detection of bruit, and 24 pa- of such bruits arise from internal carotid plaques, the tients (17.4%) sustained mild to profound frank strokes one rest coming from external carotid plaques or other un- week to 124 months postdetection. Three ofthese 24 (2.2%) died common lesions.20 The indications for endarterectomy of stroke. Asymptomatic carotid bruits may be potential stroke in patients with asymptomatic carotid bruits, however, hazards, the risk of which can be significantly reduced by have not yet been clearly defined. appropriately applied endarterectomy. A protocol for management is presented. Auscultation of the neck for the presence of carotid bruits is an important examination in patients with cerebrovascular insufficiency syndromes. In fact, this should D URING THE PAST TWO DECADES it has been clearly Jestablished that in many patients with cerebro- be done in every routine physical examination, es- vascular insufficiency the responsible atherosclerotic pecially in patients over the age of 40 and in those with occlusions are in the extracranial vasculature. In fact, evidence of atherosclerosis elsewhere in the body. Re- Hass et al.11 state that 74% ofsuch patients have at least cently developed sophisticated stethoscopes for the one significant lesion at a surgically accessible site. heart are inadequate for the head and neck. The stand- Therefore, it is technically feasible to increase cerebral ard 3 cm bell stethoscope remains the most satisfactory blood flow or remove sources of emboli by surgical one for cervical auscultation. means. Carotid endarterectomy is highly effective in The differential diagnosis of cervical murmurs in- the treatment of patients with transient cerebral cludes physiologic murmurs of no significance; venous ischemia since symptoms are relieved in most instances hum; arteriovenous fistula; angiomatous malforma- tions; intracranial neoplasm; Paget's disease ofthe skull; fever; anemia; thyrotoxicosis; atherosclerosis ofthe in- nominate, subclavian, vertebral and carotid arteries; Presented at the Annual Meeting of the American Surgical As- sociation April 26-28, 1978, Dallas, Texas. loops, kinks, and fibromuscular dysplasia ofthe carotid Reprint requests: Jesse E. Thompson, M.D., Suite 505, 3600 Gas- artery; and transmitted cardiac murmurs. In children ton Avenue, Dallas, Texas 75246. and young adults cervical murmurs are of little sig- 0003-4932/78/0900/0308 $01.05 X J. B. Lippincott Company 308 Vol. 188.9 No. 3 ASYMPTOMATIC CAROTID BRUIT 309 TABLE 1. Operative Morttality Followting Carotid Endarterectomy (Total experience -20 years) Clinical No. of No. of No. of Patient Procedure Category Patients Operations Deaths Mortality Mortality Frank stroke 296 358 20 6.8% 5.6% Transient ischemia 575 737 7 1.2% 0.9% Chronic ischemia 19 24 0 0 0 Asymptomatic bruit 132 167 0 0 0 Totals 1022 1286 27 2.6% 2.1% nificance. They are usually heard at the base of the the natural history of the untreated patient with an neck and their incidence decreases rapidly with in- asymptomatic bruit to determine ifthis lesion poses any creasing age. Over the age of 40, however, cervical stroke hazard. The second objective was to determine murmurs are much more significant, the carotid bruits the long-term outcome, as regards development of cere- being those most commonly encountered, with a re- bral ischemic episodes, of patients with asymptomatic ported incidence of about 10%.9.16 bruits subjected to primary carotid endarterectomy, The most important cervical bruit is the midcarotid, and to compare these results with those found in the heard over the carotid bifurcation near the angle of untreated group. The third is to propose a practical the jaw. It is usually highly localized and disappears and reasonable protocol for management of patients quickly as one listens inferiorly. Carotid bruits vary in with asymptomatic carotid bruits. intensity from soft to very harsh and may be graded from zero to four-plus on a quantitative basis. They Materials and Methods appear when stenosis is 50% or greater and may ac- During a 20-year period from April 16, 1957 through tually disappear at 85-90% stenosis or when the lumen April 30, 1977, we performed 1286 carotid endarterec- is only 0.5-1 mm in diameter." 20 They vary in timing tomies on 1022 from systolic to continuous. private patients for the various syndromes of cerebrovascular insufficiency (Table 1). 19 The most frequent cause of a midcarotid bruit is an In our first analysis in 1965,20 we were struck by the atherosclerotic plaque at the bifurcation of the com- finding that among 16 patients with asymptomatic bruits mon carotid artery, which usually involves the origin and first few centimeters of the internal carotid but not operated upon, five ofthe 16 sustained frank strokes without episodes of transient ischemia. Consequently, occasionally is limited to the external carotid. Rarely, two series, an operated group and a non-operated con- a bruit is present in the absence of any radiograph- trol group, have been followed pari-passu over the ically demonstrable carotid pathology. It has been at- years. A total of 270 patients with asymptomatic mid- tributed to a hemodynamic phenomenon whch may carotid result from total occlusion of the opposite carotid.2 bruits have been studied. Of these 132 were subjected to endarterectomy primarily, while 138 were Several studies have been done on patients with overt cerebrovascular insufficiency, correlating stenotic followed but were not operated upon when the bruit was first detected. The follow-up study extended lesions demonstrated on arteriograms with carotid bruits through November 15, 1977, so that all patients had a heard in the neck.6 9'16 The degree of correlation is very minimal follow-up of at least six months. high when bruits are audible, ranging from 75 to 85%. Overall correlation between demonstrable carotid dis- Table 2 shows the basic data on the two groups, which were quite similar as to age and sex distribution and ease and bruits is about 60%, since lesions may be other medical characteristics. All patients were white. present on the arteriogram yet no bruit be audible. The indications for operating upon or These include stenoses of less than 50%, ulcerated following these patients warrant explanation. In the early days of the plaques without stenosis, severe stenosis with a lumen study we were unsure as to whether they should be diameter of 1 mm or less, and total occlusions of the internal carotid artery.'9 A carotid bruit when present TABLE 2. Basic Patient Data thus constitutes a significant finding in patients with cerebrovascular insufficiency. The controversy arises as Operated Non-operated to the significance of the bruit in the absence of cere- No. of patients 132 138 bral symptoms.7'12 Age: range 42-82 years 39-86 years This paper reports our experience with asymptomatic Age: mean 64.7 years 65.7 years Males 76 (57.6%) 74 (53.6%) carotid bruits, including both non-operated and op- Females 56 (42.4%) 64 (46.4%) erated patients. The first objective was to characterize 310 THOMPSON,_gS:}.PATMAN_.....AND TALKINGTON,...:.!'i:.,.' Ann. Surg. * September 1978

FIG. 1. Right lateral carotid arteriogram showing severe stenosis at the bifurcation of the common carotid with involvement of the internal carotid giving rise to a loud, harsh carotid bruit, in a patient without neurologic symptoms. On the left is the preoperative appearance and on the right the postoperative appearance three years after carotid endarterectomy through a linear arteriotomy closed without a patch graft.

considered for operation at all. Indications for arteriog- turn for regular follow-up after other operations, al- raphy were based on clinical judgment aimed at pre- though instructed to do so. venting strokes, and included patients with harsh bruits In recent years, with increasing safety of retrograde and those about to undergo major surgery of another arteriography under local anesthesia, this procedure sort. In a few cases the referring physicians or the has been recommended and carried out more liberally. patients were insistent on arteriography. Operation was In the last year of the study the noninvasive examina- performed if a significant lesion was seen on the x-rays. tions ofoculoplethysmography (OPG) and carotid phono- A stenosis was considered significant if the diameter of angiography (CPA)15 have been useful adjuncts in de- the internal carotid was reduced 50% or more, especially termining indications for arteriography and operation. if in addition its appearance suggested the deposition of With increasing experience we have elected in some in- platelet aggregations or an ulcerated plaque (Fig. 1). stances to follow patients whom we previously op- Patients were not operated upon but followed after erated upon, even after arteriography. If there is any elective arteriography if the internal carotid stenosis bias in selection of patients for therapy, it would ap- was less than 50%, if the lesion appeared to be prin- pear to favor the non-operated group as being at less cipally in the external carotid, and if other urgent con- risk for stroke. ditions took therapeutic priority over endarterectomy All 132 patients undergoing endarterectomy had (e.g., impending gangrene). arteriography performed. In the non-operated group 81 There were various reasons for not considering arte- of 138 patients, or 58.7%, underwent arteriography riography and operation but following other patients either electively or subsequent to the onset of cerebral when first seen. In some the bruit was unilateral and symptoms. Thus 78.9% of the total 270 patients had soft. Most often the referring physician or the patient x-ray studies carried out (Fig. 1). was unwilling to accept the risk of arteriography under general anesthesia and possible subsequent opera- Results tion. Occasionally the treatment ofother disorders took precedence over management of the bruit. In some in- Operative Mortality and Morbidity stances we did not feel justified in subjecting asympto- The data on patients undergoing elective carotid end- matic patients with multiple risk factors to the addi- arterectomy are shown in Table 3. Operation was per- tional risk of arteriography unless symptoms of cerebral formed under general anesthesia with routine use of a ischemia should supervene. A few patients did not re- temporary inlying bypass shunt, as previously described VOl. 188 . NO. 3 ASYMPTOMATIC CAROTID BRUIT 311 TABLE 3. Data on Patients Having Endarterectomy eralized, nonfatal strokes, or fatal strokes during fol- No. of patients 132 low-up. In the operated group, follow-up extended from No. of operations 167 six to 184 months, with a mean of 55.1 months. For Operative mortality 0 the non-operated group, follow-up extended to 180 Operation-related deficits Transient 2 (1.2%) months with a mean of 45.5 months for the asympto- Permanent, mild 2 (1.2%) matic patients. Among the operated patients 90.9% remained asymptomatic, while in the non-operated group 55.8% developed no neurologic symptoms. Six or 4.5% of the (Fig. 2).21 There was no operative mortality. Two pa- operated patients, developed TIA's at 25,39,42,43,70, tients sustained transient neurologic deficits related to and 100 months after operation. Five of these had end- operation, which cleared completely, and two addi- arterectomy performed on the unoperated artery, tional patients had permanent mild deficits, an inci- which was appropriate to the symptoms. In the non- dence of 1.2%. Thirty-five patients, or 26.5%, had bi- operated group 37 patients or 26.8%, developed symp- lateral operations performed in separate stages. toms of transient ischemia from one to 99 months following detection of the bruit, with a mean interval of Follow-up Studies 32.1 months (Table 7). Twenty-nine of these 37 then A continuous long-term follow-up study has been had carotid endarterectomy carried out. In 10 patients carried out on both groups of patients through Novem- the internal carotid had become totally occluded with ber 15, 1977. The number of patients in each of the disappearance of the bruit. Thus the long-term occur- time intervals for the operated group is shown in Table rence ofTIA's in the non-operated group was six times 4, being divided into long-term survivors and long-term that found in the operated group. Four additional pa- deaths. No patient was lost to follow-up. Similar data tients were found to have total carotid occlusion with for the non-operated patients are displayed in Table 5. disappearance of the bruit but without ischemic symp- Long-term follow-up data on the neurologic status of toms. the operated and non-operated patients are shown in In the operated group three patients or 2.3% de- Table 6. Patients are listed as asymptomatic if they veloped nonfatal strokes at 11, 26, and 67 months post- were asymptomatic neurologically at the end of the operative, while among the non-operated patients 21, study or at time of death from other causes. The re- or 15.2% developed frank strokes from one week to maining patients are listed as having developed tran- 124 months after the bruit was first heard, with a mean sient cerebral ischemia (TIA's) either localized or gen- interval of 20.3 months (Table 7). Nine of these 21 pa-

:~~~~~~~~~~~ ~~~...... *..; .. .;,A,.s; -: 'Al'~~~~~~~~~~~~~~~.^ . ....

FIG. 2. Drawing illus- ...... V~~~~~~~~~~~ ~ ...... ; . f v ... .. - ... trating the technique of carotid endarterectomy employing a #10 Fr. plastic catheter as a temporary inlying shunt for cerebral protection, with a linear arteriotomy which is closed without .__ a patch graft. (From J. E. Thompson and C. M. Talkington, Caro- tid Endarterectomy, Ann. Surg., 184:1, 1976.) : 312 THOMPSON, PATMAN AND TALKINGTON Ann. Surg. * September 1978 TABLE 4. Length of Follow-up on Patients Operated upon It should be noted that the incidence of TIA's and for Asymptomatic Carotid Bruits strokes occurring during follow-up after prophylactic Time Followed No. of Long- No. of Long- Total No. operation in patients with asymptomatic bruits is very (Months) term Survivors term Deaths of Patients similar to that found in numerous long-term studies of 6-12 11 9 20 patients with transient ischemic attacks subjected to 13-24 16 2 18 therapeutic endarterectomy.21 25-36 12 5 17 37-48 9 4 13 49-60 7 3 10 Discussion 61-72 9 5 14 73-84 8 3 11 It appears from our data that certain individuals with 85-96 2 5 7 asymptomatic carotid bruits are at definite risk for 97-108 1 4 5 ischemic cerebral episodes. The clinical consequences 109-120 4 1 5 121-132 1 2 3 which we have observed in these patients during long- 133-144 5 5 term follow-up may be listed as follows: 1) nothing 145-156 1 1 may happen; 2) transient cerebral ischemic attacks 157-168 2 2 181-192 1 1 may supervene; 3) frank strokes may occur without intervening episodes of transient ischemia; 4) total oc- 89 43 132 clusion of the artery may occur without symptoms; and 5) total occlusion may occur with production of either transient ischemia or frank stroke. The hazard tients subsequently underwent carotid endarterectomy. depends directly upon the lesion giving rise to the bruit The incidence of nonfatal strokes among the non-op- and the status of all vessels supplying the brain, both erated patients is thus 6.5 times greater than that found primary and collateral. Thus, little hazard is posed from in the operated group. bruits arising from stenosis of the external carotid or In the operated series three patients or 2.3% died of from fibromuscular dysplasia. On the other hand, bruits strokes at 74, 81, and 131 months postoperative. Like- coming from atherosclerotic plaques involving the in- wise in the non-operated group three patients or 2.2% ternal carotid become symptomatic in a significant per- suffered fatal strokes at six, 48, and 124 months fol- centage of cases if followed long enough. lowing detection of the bruit. The report of Javid et al.13 on the natural history Table 8 lists the types of frank strokes occurring in of growth of carotid atheromas has important implica- the 24 patients in the non-operated group during the tions with regard to management of carotid bruits. On follow-up period. The ages of these patients ranged serial arteriograms over a period of one to nine years, from 39 to 84 years, with an average age of 65. It is evi- they noted no change in size ofthe atheromas in 38% of dent that the majority of these were severe deficits. Of the lesions studied, but found a significant increase in the 24 patients, 10 were found to have total occlusion of 62% of the atheromas. The increase was greater than the internal carotid artery with disappearance of the 25% per year in 34% of lesions, was less than 25% per bruit. During follow-up 43 of 132 patients in the operated group died, 32.6% (Table 4), while 50 of 138 patients TABLE 5. Length of Follow-up on Non-operated Patients with Asymptomatic Carotid Bruits in the non-operated group died, 36.2% (Table 5). The causes of long-term deaths are listed in Table 9. 72% Time Followed No. of Long- No. of Long- Total No. of the deaths among the operated patients and 48% of (Months) term Survivors term Deaths of Patients those in the non-operated group were due to cardiac 0-12 19 12 31 disease, thus pointing up the severity and widespread 13-24 14 5 19 nature of the atherosclerotic process in these elderly 25-36 9 6 15 with cerebrovascular disease. 37-48 11 6 17 patients 49-60 9 6 15 In the operated series 35 of 132 patients, or 26.5%, had 61-72 5 3 8 bilateral operations for asymptomatic bruits. In the 73-84 6 1 7 85-96 7 2 control series 66 of 138 or 9 patients, 47.8%, had bilateral 97-108 1 1 2 bruits. Among those patients developing TIA's, 16 of37, 109-120 2 1 3 or 43%, had bilateral murmurs, while 12 of 24, or 50%, 121-132 2 2 133-144 1 4 5 of those going on to frank stokes had bilateral bruits. 145-156 2 1 3 The absence of a bruit on one side, however, does not 180-200 2 2 necessarily indicate a patent artery as the internal ca- 88 50 138 rotid may be totally occluded. VOl. 188.o NO. 3 ASYMPTOMATIC CAROTID BRUIT 313 TABLE 6. Long-term Follow-up Data on Operated and Non-operated Patients Stroke Stroke Asymptomatic TIA's Nonfatal Fatal Length of follow-up Operated 120 6 3 3 6 to 184 months 132 patients 90.9% 4.5% 2.3% 2.3% mean-55.1 mos. Non-operated 77 37 21 3 To 180 months 138 patients 55.8% 26.8% 15.2% 2.2% mean -45.5mos.(ASX) Significance p < 0.01 p < 0.01 p < 0.01 year in 20%, while recurrent stenosis or thrombosis oc- Corroborating the findings which we have presented curred in 7.4% here, Cooperman and Evans5 have followed 60 patients It does not appear unreasonable, therefore, to con- with asymptomatic bruits from two to seven years. sider the asymptomatic carotid bruit as part ofthe total Twelve patients, or 20%, developed TIA's, while five picture of cerebrovascular insufficiency rather than an patients had nonfatal strokes (8.3%) and four had fatal isolated finding on physical examination. The natural strokes (6.7%) for a total stroke incidence of 15% and history ofischemic thrombotic stroke due to extracran- an overall incidence of ischemic episodes of 35%. ial lesions must begin somewhere (Fig. 3). It may be- Thirty-five per cent ofthe patients died ofother causes. gin as a plaque at the common carotid bifurcation and Thirty per cent were alive and neurologically asympto- its first physical manifestation be an asymptomatic bruit. matic at the end of the study. With time the asymptomatic lesion becomes sympto- In a screening survey of 1287 patients with asymptomatic from ulceration and embolization, or from im- matic cervical murmurs, Kartchner and McRae15 found pairment of cerebral blood flow. One would hope the a significantly positive OPG-CPA test in 52% of 242 first symptom is a TIA, when therapy can be initiated. patients with significant carotid bifurcation bruits. In At times, however, the first symptom is hemiplegia, the total series, during a 6-70 month follow-up, 31 pa- especially if a stenotic carotid undergoes acute total tients developed TIA's, 38 patients sustained frank occlusion. This sequence of events is seen repeatedly strokes, eight died from strokes, and 135 patients un- in retrospective studies of patients with completed derwent 154 carotid endarterectomy procedures. strokes. Many other factors enter in to complicate this Likewise, Gee et al.8 studied 157 asymptomatic bruits simplistic scheme; namely, multiple lesions both extra- in 116 patients by means of ocular pneumoplethysmog- cranial and intracranial, anatomic configurations of raphy (OPG-Gee). On the basis of this examination, 41 cerebral collateral pathways, rate of progression of patients underwent arteriography and 22 of these were atherosclerosis in the individual patient, hypertension, considered to be at sufficient risk to have carotid end- diabetes, etc., to mention some of the more important arterectomy performed. ones. The length of time during which these bruits Although the figures for the incidence of cerebral are present is also very important. ischemic episodes in the studies quoted above differ from our own, for a number of reasons, the data do fit TABLE 7. Interval From Detection of Bruit to Onset of Ischemic with the concept enunciated here; namely, that an Episode in Non-operated Patients asymptomatic carotid bruit may point out the patient Interval No. of Patients No. of Patients with a potential stroke hazard. It represents an early (Months) with TIA's With Strokes stage in the clinical evolution of cerebrovascular insufficiency just as TIA's have been shown in a number 0-12 10 15 13-24 9 2 of studies21 to be forerunners of actual strokes in 30- 25-36 5 3 35% of cases followed three to five years or longer. 37-48 3 2 49-60 3 61-72 1 1 TABLE 8. Types of Strokes Occurring in 24 Patients 73-84 4 in the Non-operated Group 85-96 1 97-108 1 Profound frank stroke, coma 6 109-120 Hemiplegia 7 121-132 1 Hemiparesis, severe 6 No. of pts. 37 24 Hemiparesis, mild 2 Range 1-99 mo 1 week to 124 months Permanent blindness, partial 3 Mean interval 32.1 mo 20.3 mo 24 314 THOMPSON, PATMAN AND TALKINGTON Ann. Surg. o September 1978 TABLE 9. Causes of Long-Term Deaths ing, 2) cerebral arteriography and 3) carotid endarter- Cause of Death Operated Non-operated ectomy. Cardiac 31 24 Noninvasive Screening Cerebral 3 8* Malignancy 4 1 Noninvasive screening tests may be applied to all Following other surgery 2 2 Generalized atherosclerosis 1 I patients. Several different methods are available.21 At Uremia I I present we use the OPG-CPA (Kartchner) and supra- Ruptured aortic aneurysm I orbital Doppler studies. The ease and safety of such Mesenteric infarction 3 Gastrointestinal hemorrhage 2 examinations makes possible serial testing at regular Burn I intervals to determine if a bruit-producing lesion found Emphysema I initially to be insignificant is indeed progressing towards Auto accident I During arteriography 1 one of significance, when arteriography may be re- Cirrhosis 1 quired. 15 Undetermined 3 43 50 Cerebral Arteriography * Includes patients going from asymptomatic to TIA's and non- As cerebral arteriography has become increasingly fatal strokes dying later of cerebral causes. safer with retrograde techniques and local anesthesia, it may be recommended more liberally than previously, but not routinely, in evaluating asymptomatic bruits of The questions that arise when one first hears a bruit grade II intensity or greater. The overall general status in an asymptomatic patient are: does the murmur de- of each patient shQuld be considered very carefully. note a significant lesion in the internal carotid artery, Arteriography should not be done if some contraindica- and how can one determine its significance without tion to endarterectomy already exists. It is not to be subjecting the patient to the risk ofunnecessary arteriog- recommended if the bruit is soft and unilateral, if other raphy? Safe, simple, and reliable noninvasive screen- conditions take priority over study ofthe bruit, or ifthe ing tests have been needed. Several such tests have already been developed while a number of others are under intensive investigation.21 Examples ofthe former have been mentioned above, (Kartchner and McRae,'5 Gee, et al.8) while the latter include various types of ultrasonic scanning methods.'018 With perfection of these techniques in the future it should be possible with noninvasive examinations to assess both anatomic and functional hemodynamic components ofthe lesions responsible for bruits, thus making more precise the indications for arteriography, which remains at present the definitive diagnostic maneuver. Once arteriography has been accomplished, indications for endarterectomy are usually straightforward. One factor which is unpredictable is the rate at which atherosclerosis progresses in the individual patient. Most common is a moderate rate of progression with a carotid lesion becoming symptomatic over three to four years. Some lesions progress very slowly or hardly at all while others may progress rapidly to produce symptoms in a year or two. The only way this can be determined is by careful follow-up examinations at appropriate intervals. FIG. 3. Diagram showing the various manifestations which may re- Protocol for Management sult during the natural history of development of an atherosclerotic plaque at the common carotid bifurcation, from asymptomatic bruit Management of the patient with an asymptomatic to total occlusion with acute stroke. (From J. E. Thompson and carotid bruit follows three steps: 1) noninvasive screen- C. M. Talkington, Carotid Endarterectomy, Ann. Surg. 184:1, 1976.) Vol. 188 . No. 3 ASYMPTOMATIC CAROTID BRUIT 315 noninvasive tests are negative. It may be recommended tion. They and others recommend arteriographic if bruits are bilateral and harsh, in patients with known study of symptomatic and asymptomatic carotid lesions progressive atherosclerosis elsewhere, prior to other before coronary artery surgery. If hazardous lesions major operations, when noninvasive tests are positive, are found, they may be repaired before, simultaneously and when one's best clinical judgment indicates that it with, or after the cardiac procedure, depending upon is necessary. An experienced arteriographer should be the situation in the individual patient.3'17'23 available. Although at present, with skillful anesthetic management and avoidance of hypotension, the risk of stroke Carotid Endarterectomy attendant upon most operative procedures in the presence of an asymptomatic carotid stenosis is quite low, If the arteriograms show that the bruit arises from a ischemic accidents continue to occur.15 In our own lesion posing no stroke hazard, operation need not be series three strokes occurred following femoropopliteal considered. If a significant atherosclerotic stenosis is bypass, inguinal herniorrhaphy, and transurethral re- found in the common or internal carotid, endarter- section. Patients in this category warrant serious con- ectomy may be recommended. Specific indications in- sideration and should at the very least have preopera- clude 1) bilateral stenoses; 2) unilateral stenosis with tive evaluation by means of noninvasive tests. If contralateral occlusion; 3) stenosis in the artery to the the contemplated operation is a vascular one, where dominant hemisphere; 4) known progressive athero- arteriography is obligatory, it would seem advisable to sclerosis elsewhere in the peripheral vasculature, es- study the cerebral vasculature during the same x-ray pecially in younger patients; 5) contemplated major examination, provided this poses no undue risk to the operation of another sort, particularly open-heart sur- patient. gery, and 6) a markedly ulcerated plaque. In summary, the data presented provide information If prophylactic carotid surgery is to be considered, on the natural history ofpatients with untreated asympto- multiple risk factors, such as a history of hypertension, matic carotid bruits originating in the internal carotid myocardial infarction and congestive heart failure in pa- artery from atherosclerotic plaques, which may pre- tients over 65, should not be present.14 This is pointed dispose to strokes in certain individuals over the age up by the distressingly high long-term mortality from of 40. Recently developed noninvasive screening tests heart disease during the early years offollow-up. (Tables are helpful in determining the hemodynamic significance 4, 5 and 9) Since no unnecessary technical risks should of these bruits, which ultimately require arteriography be taken, appropriate measures for cerebral protection for precise diagnosis. If hazardous lesions are dem- must be used during endarterectomy to avoid producing onstrated, prophylactic carotid endarterectomy may be neurologic deficits. Our recommendation is the routine performed in carefully selected patients, with minimal use of a temporary inlying shunt. Operative mortality mortality and morbidity. Patients treated by operation should be below 1% and complications no more than 2%. appear to have a more favorable long-term out-look, Over the years prophylactic carotid surgery has been from the standpoint of subsequent ischemic cerebral recommended for the asymptomatic patient with carotid episodes, than their non-operated counterparts. A prac- bruits who is about to undergo a major operation of tical regimen for management is presented. another sort, where a hypotensive episode might well result in a stroke.19 Two recent reports question the References validity of this indication, citing the low degree of correlation between presence of bruits and incidence of 1. Allen, N.: The Significance of Vascular Murmurs in the Head postoperative stroke in patients undergoing aortic and Neck. Geriatrics, 20:525, 1965. 2. Allen, N. and Mustian, V.: Origin and Significance of Vascular operations.4'22 On the other hand, Fields7 has considered Murmurs of the Head and Neck. Medicine, 41:227, 1962. this a valid reason for performing arteriography and 3. Bernhard, V. M., Johnson, W. D. and Peterson, Jon J.: Carotid operation in carefully selected patients, based on Artery Stenosis, Association With Surgery for Coronary Ar- tery Disease. Arch. Surg., 105:837, 1972. his personal clinical experience. 4. Carney, W. I., Jr., Stewart, W. B., DePinto, D. J., et al.: Carotid The procedures which appear to carry the greatest Bruit as a Risk Factor in Aortoiliac Reconstruction. Surgery, risk of operation-related neurologic deficits in the pres- 81:567, 1977. 5. Cooperman, M. and Evans, W. E.: Unpublished Data. ence of carotid stenoses are the open-heart operations, 6. David, T. E., Humphries, A. W., Young, J. R. and Beven, E. G.: especially those for coronary artery bypass. Mehigan A Correlation of Neck Bruits and Arteriosclerotic Carotid et al.'7 have reported operative strokes occurring in the Arteries. Arch. Surg., 107:729, 1973. 7. Fields, W. S.: The Asymptomatic Carotid Bruit-Operate or cerebral hemisphere with known extracranial occlu- Not. Current Concepts of Cerebrovasc. Dis. Stroke, 13:1, sions not removed prior to myocardial revasculariza- 1978. 316 THOMPSON, PATMAN AND TALKINGTON Ann. Surg. * September 1978 8. Gee, W., Oller, D. W., Amundsen, D. G. and Goodreau, J. J.: Whisnant, J. P. (eds.) Cerebral Vascular Diseases. New York, The Asymptomatic Bruit and the Ocular Pneumoplethysmog- Grune and Stratton, 1966. raphy. Arch. Surg., 112:1381, 1977. 17. Mehigan, J. T., Buch, W. S., Pipkin, R. D. and Fogarty, T. J.: 9. Gilroy, J. and Meyer, J. S.: Auscultation ofthe Neck in Occlusive A Planned Approach to Coexistent Cerebrovascular Disease Cerebrovascular Disease. Circulation, 25:300, 1962. in Coronary Artery Bypass Candidates. Arch. Surg., 112: 10. Hajjar, W. M. and Sumner, D. S.: Comparative Study of Carotid 1403, 1977. Ultrasonic Arteriography and Oculoplethysmography and 18. Strandness, D. E., Jr., Ward, K. J., Phillips, D. J. and Harley, Contrast Angiography. Stroke, 9:12, 1978. J. D.: Evaluation of Carotid Disease by Several Noninvasive 11. Hass, W. K., Fields, W. S., North, R. R., et al.: Joint Study of Methods. Stroke, 9:12, 1978. Extracranial Arterial Occlusion: II. Arteriography, Tech- 19. Thompson, J. E.: Surgery for Cerebrovascular Insufficiency niques, Sites, and Complications. JAMA, 203:961, 1968. (Stroke). Springfield, Thomas, 1968. 12. Humphries, A. W., Young, J. R., Santilli, P. H., et al.: Un- 20. Thompson, J. E., Kartchner, M. M., Austin, D. J., et al.: Carotid operated, Asymptomatic Significant Internal Carotid Artery Endarterectomy for Cerebrovascular Insufficiency (Stroke): Stenosis: A Review of 182 Instances. Surgery, 80:695, 1976. Follow-Up of 359 cases. Ann. Surg., 163:751, 1966. 13. Javid, H., Ostermiller, W. E., Hengesh, J. W., et al.: Natural 21. Thompson, J. E. and Talkington, C. M.: Carotid Endarterectomy: History of Carotid Bifurcation Atheroma. Surgery, 67:80, Surgical Progress. Ann Surg., 184:1, 1976. 1970. 22. Treiman, R. L., Foran, R. F., Shore, E. H. and Levin, P. M.: 14. Javid, H., Ostermiller, W. E., Hengesh, J. W., et al.: Carotid Carotid Bruit, Significance in Patients Undergoing an Ab- Endarterectomy for Asymptomatic Patients. Arch. Surg., 102: dominal Aortic Operation. Arch. Surg., 106:803, 1973. 389, 1971. 23. Urschel, H. C., Razzuk, M. A. and Gardner, M. A.: Manage- 15. Kartchner, M. M. and McRae, L. P.: Noninvasive Evaluation ment of Concomitant Occlusive Disease of the Carotid and and Management of the "Asymptomatic" Carotid Bruit. Sur- Coronary Arteries. J. Thorac. and Cardiovasc. Surg., 72:829, gery, 82:840, 1977. 1976. 16. McDowell, F., Rennie, L. and Ejrup, B.: Arterial bruit in cere- 24. Wylie, E. J. and Ehrenfeld, W. K.: Extracranial Occlusive Cere- brovascular disease. In Millikan, C. H., Siekert, R. G. and brovascular Disease. Philadelphia, Saunders, 1970.

DISCUSSION Ifthe patient, awake and responding to the anesthesiologist, tolerates triple vessel clamping for three to four minutes, measurement of DR. CHARLES G. ROB (Rochester, New York): I agree with every- pressure and use of internal shunting are not necessary. The opera- thing Dr. Thompson said, but I want to add two points. tion is then simplified considerably for most surgeons. The first one is that in our experience the best bruits are from When we use an external Javid shunt, the correction of a high those patients with stenosis of the external carotid artery, and this lesion with some traction on the shunt may cause the distal end is usually not a surgical lesion. The second point is that in our ex- of the Javid tube to angulate against the wall of the internal carotid perience, a completely asymptomatic internal carotid bruit is quite and this can embarrass cerebral flow. This isn't noticed with a patient rare. After we have examined and interviewed such a patient, we under general anesthesia, but under regional anesthesia it becomes usually find that they have symptoms which have not been noted apparent very quickly, as the patient becomes confused or loses before, either by the patient or his doctor. consciousness. There's no question that in Dr. Thompson's hands the use of DR. ROBERT J. BAKER (Chicago, Illinois): Dr. Thompson and his the shunt is part and parcel of a very simple procedure, but for group have presented a comprehensive review of one of the largest those surgeons who are not quite so experienced there is an ap- series of carotid endarterectomies that has been reported. His re- propriate place for regional anesthesia, and we prefer it, since any sults are impressive, as befits the experience and talent of his group, difficulty with motor or cerebral function is immediately recognized. and there is little with which one can differ. However, for those of us who are active in teaching centers, DR. JESSE E. THOMPSON (Closing discussion): Dr. Rob is probably where 95% ofour carotid endarterectomies are being done by surgical a better history-taker than most of us. We have observed however residents with one of us assisting, our experience has been that that patients called asymptomatic after being operated upon will the use of the indwelling shunt has sometimes complicated the tech- frequently tell you that they do feel better in many respects and nical procedure. This is certainly true in diabetic patients with ex- did have some symptoms of which they were not aware preopera- tensive internal carotid plaque. tively. So, I think his point is well taken. For that reason, we have employed a s6mewhat different anes- As for Dr. Baker, I think one should use the type of cerebral thetic-basically no real change in the surgical technique-namely, protection that suits the surgeon. We have found over the years, regional anesthesia (Slide). Patients with an appropriate emotional having used first local anesthesia and then general anesthesia with- set who tolerate the regional anesthesia well, and this turns out to out any shunt, that at the present time general anesthesia with the be at least 95% ofindividuals, are candidates for regional anesthesia. routine use of a shunt is best for us. Others, as you know, use The cervical plexus is readily blocked, at the level of C-2, 3 and 4, selective shunts, either under local or general anesthesia, using stump resulting in excellent anesthesia. pressures or EEG measurements. Once one becomes accustomed (Slide) This dye, which was injected in this and in several other to the technique, the shunt really does not get in the way and presents patients at the time that the local anesthetic was injected, rapidly no real hindrance. One has to use what is best for himself, as well diffuses vertically throughout the entire prevertebral sheath, as this as what is best for the patient. cervical radiograph shows; therefore, one gets a very complete cer- In closing, I should state that although an asymptomatic bruit vical block. In fact, there is a transverse extension of this particular usually arises from the lesion that is responsible for a TIA or a dye column at the brachial plexus level, and often a brachial plexus stroke, as these patients are followed over the years, occasionally block results, in addition. Fortunately, this is on the ipsilateral side, deficits may occur from other lesions. This is apropos of Dr. Rob's so that the surgeon doesn't become too concerned about having statement relative to external carotid plaques, which may well im- caused the weakness in the arm and the shoulder postoperatively. For pinge on the internal carotid as well. So, the bruit may be most practical reasons, we warn patients about this possibility in advance. important as an indicator calling attention to the patient who has With a cervical block, clamping the common, the internal and cerebrovascular disease, whether it be in the internal carotid, exter- the external carotids provides a practical test of cerebral perfusion. nal carotid, extracranial or intracranial.