amaurosis fugax: some aspects of management · permanent monocular blindness, complete hemisphere...

Journal of Neurology, Neurosurgery, and Psvchiatry 1982;45:1-6

Amaurosis fugax: some aspects of managementPJ PARKIN, BE KENDALL, J MARSHALL, WI McDONALD

From the National Hospital for Nervous Diseases, Queen Square and Maida Vale, and the Moorfields EyeHospital, London

SUMMARY Fifty-one patients with amaurosis fugax were followed for a mean of 4 9 years from theirfirst attack. Females predominated under the age of 50 years in contrast to men who presented in theolder age group. Minor permanent visual sequelae occurred in only three patients, but cerebralvascular symptoms were present at some time in just under half the group. A range of abnormalitieswas identified on cerebral angiography and some of these correlated with certain clinical findings.Twenty patients were treated by surgery and permanent relief or significant improvement in symptomsoccurred in 14. A group of patients who were at greater risk of cerebral vascular complicationsfollowing angiography and surgery was identified. It is concluded that careful patient selection isnecessary before surgery is recommended but that in a significant number of cases with relativelyfocal atheroma confined to one proximal internal carotid artery an excellent long term resultfollowing surgery may be expected.

Descriptions of amaurosis fugax are on record sincethe early 1800s but it was not until as recently asnearly 30 years ago that Fisher drew attention to theassociation of transient attacks of monocularblindness with contralateral hemiplegia.1 Since then,radiological and pathological experience has con-vincingly confirmed the relationship of amaurosisfugax to atheromatous disease of the carotid arteryand to the risk of stroke.2 The natural history ofamaurosis fugax has been most clearly defined byMarshall and Meadows in 1968, when they followed80 patients up to four years after the onset ofsymptoms. Permanent monocular blindness,complete hemisphere stroke or both followed anattack of amaurosis fugax in 16 %.3 A surgicalapproach to therapy was therefore advocated byEhrenfeld and others when they described theoutcome of 44 patients with amaurosis fugax. Of 12unoperated patients reviewed retrospectively, 10 haddeveloped stroke or permanent blindness. Nearly allthe cases treated by carotid endarterectomy wererelieved of symptoms.4 More recently, Mungas andBaker treated 80 patients by carotid endarterectomy.

Address for reprint requests: Professor WI McDonald,The National Hospital, Queen Square, London WCIN 3BG,UK.

Received 5 October 1981Accepted 8 October 1981

Relief of symptoms occurred in 90% but the meanlength of follow-up was little over one year.5We have recently reviewed our own experience of

managing patients with amaurosis fugax over a sevenyear period. Although we have reviewed all patientspresenting in that time we have paid particular atten-tion to establishing the outcome of those treated bysurgery.

Clinical material

Fifty-six patients were seen over a seven year period from1973.They were referred from the clinics of an ophthalmo-logical hospital and a general hospital, from physicians inother centres and by direct referral from familypractitioners. Patients whose visual symptoms may havebeen attributable to primary ophthalmologic disease or tointracerebral disease have not been considered andpatients with pre-existing monocular visual impairmenthave also been excluded. All patients had experienced atleast one attack of transient monocular blindness. Forthe purposes of this study amaurosis fugax was defined aspartial or complete transient monocular blindness withtotal recovery within 24 hours. In fact, the duration ofvisual loss was rarely longer than a few minutes in thegreat majority. In all patients the frequency of attacks overthe period of follow-up was established and particularattention was paid to the occurrence of symptomssuggesting transient cerebral ischaemic attacks (TIA),peripheral vascular disease and coronary heart disease.All patients underwent clinical re-examination. Cerebralangiograms performed during the original admission werereviewed.

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Parkin, Kendall, Marshall, McDonald

Results

One patient had died of carcinoma of the pancreas.Four others could not be traced and their fate isunknown. Fifty-one patients were reviewed, a mean4 9 years from the onset of their first attack and amean of four years from the time of presentation.Seven of the patients had a history of either TIA orcompleted stroke prior to developing amaurosisfugax and they have been followed for a mean of 5-1years from the first cerebral vascular symptom.

SEX INCIDENCEThe sex incidence in the whole group showed a malepredominance of 2-6 :1. Females, however, morecommonly presented under the age of 50 years incontrast to males who showed a striking predomin-ance over that age (table 1).

Table 1 Distribution ofpatients according to age andsex

Age Males Females Total

30-39 2 1 340-49 4 9 1350-59 16 1760-69 12 3 1570 79 3 0 3Total 37 14 51

PERMANENT VISUAL SEQUELAEPersisting visual sequelae occurred in three patients.A sector field defect was present in all and in two ofthem an impacted retinal embolus was visible. In nopatient was the peripheral field defect a major visualhandicap. The attacks of amaurosis fugax had lasteda few minutes in one patient, 30-60 minutes inanother and in the third patient some attacks hadlasted for up to 12 hours.

CEREBRAL VASCULAR SYMPTOMSCerebral vascular symptoms (TIA or stroke) occurredin 22 patients (43 %), either preceding or followingamaurosis fugax (table 2). Of 44 patients in the serieswho were without cerebral ischaemic symptoms priorto the onset of amaurosis fugax, 15 (34 %) subse-quently developed TIA or stroke.

Table 2 Associated cerebral vascular symptoms in 22patients with amaurosisfugax

Cerebral vascular symptoms-Before amaurosis 7Following amaurosis 11

Simultaneous TIA and amaurosis ISimultaneous stroke and amaurosis 1Asymptomatic focal signs 2

Total 22

RETINAL EMBOLIRetinal emboli were present at some time in eightpatients (seven at the time of presentation; one atfollow-up). In six, the emboli were refractile yellowcrystals and in two the nature is uncertain. Two wereassociated with retinal arteriolar branch occlusion.All but one patient had an ipsilateral carotid bruit.Coronary heart disease or peripheral vasculardisease was present in five. All four patients under-going cerebral angiography had a localised athero-matous lesion suitable for carotid endarterectomy.One patient in this group, who received no therapy,developed stroke and one patient developed TIAresponding to antiplatelet therapy.

MULTIPLE ATTACKS

Multiple attacks, defined as greater than 20 prior topresentation, had occurred in 13 patients. Althoughthey received a variety of treatments, none haddeveloped permanent visual sequelae by the time offollow-up. Carotid territory TIAs had occurredbefore visual symptoms in two patients and a furtherthree developed TIAs later.

BILATERAL ATTACKSIn five patients attacks of amaurosis fugax wereindependently bilateral. Bilateral angiography wasperformed in four of them and a localised unilateralproximal internal carotid lesion was present in three.All four angiograms, however, showed atheromatousirregularity of variable degree on both sides. Onepatient later developed stroke; one developed TIAsthat persisted despite unilateral carotid endarterec-tomy and later treatment with anticoagulants; and intwo patients the attacks ceased spontaneously andthe patients remain well.

ASSOCIATED DISORDERSAn elevation in the fasting level of serum cholesterolor triglycerides above 6 5 mmol/l or 1 7 mmol/lrespectively was present in 31 patients (61 %). Thediastolic blood pressure exceeded 100 mm Hg in ninepatients (18 %). A family history of ischaemic heartdisease, peripheral vascular disease or stroke underthe age of 60 years was present in 19 patients (37 °/,).An abnormality of the electrocardiogram waspresent in six; five showed ischaemic or hyper-tensive changes and one showed atrial fibrillation.Clinical evidence of ischaemic heart disease orperipheral vascular disease was noted at presentationin 13 patients (25 %) and at follow-up in an additionalnine patients (18 %).

CEREBRAL ANGIOGRAPHYThirty-eight patients underwent cerebral angiography,a greater proportion of patients under the age of 50

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years being investigated in this way (14 of 16patients). Carotid angiography was performedinitially on the symptomatic side and the con-tralateral carotid examined only if a potentiallysurgically treatable lesion had been shown. Allstudies were performed under general anaesthesiawith controlled ventilation. Catheterisation via atransfemoral approach was the procedure mostcommonly used. Direct common carotid puncturealone was the method employed in some cases, butwas also used to supplement the former examinationif difficulty with selective catheterisation wasencountered. Thus, half the patients studied byangiography were subjected to carotid puncture.

In the 24 patients over the age of 50 yr, angio-graphy demonstrated irregularity or stenosis of theproximal internal carotid artery suitable for endarter-ectomy in 16 (67 %). By contrast this abnormality waspresent in only five of 14 angiograms (36%) per-formed in the younger age group. Vessel wallirregularity, however, was generally more widespreadthan this and all but four patients showed additionaldisease of variable severity in the distal carotidcirculation on the same side and all but two showeddisease at some point in the contralateral carotidcirculation. The presence of certain clinical featuresin the patients showing a carotid lesion suitable forsurgery are listed in table 3. Of the 21 cases with anoperable carotid lesion, only three did not have anipsilateral carotid bruit or hypertension or both, andin the under 50 year age group no patient was with-out one of these signs.

Table 3 Clinical signs and the presence of a promnixalinternal carotid lesion suitable for surgery. Front 38patients studied by angiography

Nunmber ofpatients Numnber withi a "surgical"lesion

Bruit 14 1 2TIA or stroke 16 10Hypertension 7 5Age under 50 14 5Age over 50 24 15

In addition to the 21 angiograms described above,angiography demonstrated complete carotid occlusionin four patients (one of whom also had a surgicallytreatable lesion on the other side); severe focalirregularity of the carotid siphon (one patient); mildproximal internal carotid irregularity (five patients);minimal carotid irregularity (seven patients); and noabnormality (one patient). The ophthalmic arteryfailed to fill in two patients. In the angiograms ofthree patients, retrograde filling of the ophthalmicartery by collateral vessels from the external carotidartery was present and this was associated with high

grade stenosis of the proximal internal carotidartery in two and with complete carotid occlusion inone.Angiography was associated with complications in

three patients. One of them, aged 50 years, hadalready experienced a minor stroke before presen-tation and this was made worse following angio-graphy and a moderate disability persists. Twoothers, aged 45 and 61 years, sustained minor strokeswithin 24 hours of angiography; one recoveredcompletely and the other was left with a mildresidual disability. Complete internal carotid arteryocclusion was present in two of these patients and asevere stenosis of the carotid siphon was present in thethird. In all three cases angiography had beenperformed by direct common carotid puncture.

PATIENTS TREATED BY SURGERYTwenty patients underwent surgery. Carotid endar-terectomy was performed on 19 and one patient wastreated by extracranial-intracranial anastomosis asthe primary procedure. A number of the patientscontinued to receive prophylactic antiplateletaggregation therapy after operation.

Four patients underwent more than one operation.One experienced a recurrence of amaurosis fugax andTIAs 10 months after endarterectomy. Angiographyshowed a re-stenosis of the internal carotid artery atits origin and a second endarterectomy was followedby abolition of symptoms for 21 years before theyreturned. A second patient had a critical proximalinternal carotid stenosis demonstrated by angio-graphy but had developed carotid occlusion by thetime of operation and because of this extracranial-intracranial anastomosis was performed one weeklater. A third patient required external carotidendarterectomy following endarterectomy of theinternal carotid because of continuing symptoms.The fourth patient experienced no improvement insymptoms following internal carotid endarterectomyand underwent the same procedure on the contra-lateral side 4 months later.The average age of the surgically treated patients

was 56 5 years and the average duration of follow-upfrom the time of surgery is 4-0 years. Eleven patientswere relieved of all symptoms, including two withTIA and three with multiple attacks of amaurosisfugax. Three further patients had a significantreduction in the frequency of attacks followingsurgery. One of these had a single recurrence ofamaurosis 4 months after surgery but remains well7 years later; one was relieved of symptoms for 3years before amaurosis fugax recurred; in onepatient the attacks were abolished for 10 monthsbefore they recurred and re-endarterectomy againabolished symptoms for 2i years.

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In two patients the frequency of attacks wasunchanged by surgery, each patient having experi-enced both multiple attacks of amaurosis fugax andTIAs. They were also unresponsive to anticoagulantand antiplatelet therapy. One patient was worse asresult of surgery, having developed carotid throm-bosis by the time of operation and this resulted in amild persisting hemiparesis. In three patients thefrequency of attacks was reduced for a periodfollowing surgery but they developed stroke 8-28months later in the same carotid territory. A historyof TIA had been present in two of them prior tooperation. In one, the internal carotid artery on thesymptomatic side was completely occluded andendarterectomy was performed for a stenosis on theother side. The second patient had, in addition to aproximal internal carotid stenosis, severe disease inthe ipsilateral carotid siphon. In the third patient,angiography had been interpreted as showingcomplete occlusion of the internal carotid withretrograde distal filling from the ophthalmic


artery, and she underwent extracranial-intracranialanastomosis as the primary procedure. Our review ofthe serial subtraction films from this angiogramrevealed that progressive retrograde filling of thedistal internal carotid occurred until it encountered aprofoundly slowed anterograde flow from theproximal internal carotid artery. Thus the carotidsystem was in fact patent although the profoundslowing in blood flow resulting from a criticalproximal stenosis had simulated internal carotidocclusion (fig).Four other patients experienced minor sequelae

following surgery. Two had minor completed strokeswhich recovered within 1-2 weeks; one complained ofpersistent pain about the operation site; one devel-oped a transient hypoglossal palsy.

Discussion

The importance of amaurosis fugax as a marker ofcarotid arterial disease is emphasised by the experi-

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Amaurosis fugax: some aspects of management

ence of our study. When considered without regardto therapy, just under half the patients in our serieshad developed TIA or stroke within the period offollow-up. Amaurosis fugax may also be a marker ofmore generalised disease as evidenced by the fact thatjust under half had developed peripheral vasculardisease or ischaemic heart disease by the time offollow-up.The neurological prognosis in the individual who

presents with isolated amaurosis fugax is difficult topredict on clinical grounds. Neither the frequencynor the duration of the attacks seemed to bear anydirect relationship to the risk of developing cerebralvascular complications and this was also the experi-ence of Marshall and Meadows.3 Permanent visualsequelae occurred in only three patients in our seriesand in two of them the duration of individual attacksof amaurosis fugax was longer than the few minutesthat characterised attacks in the majority of patients.However, in the small number in whom the attacksdid last for a longer period the risk of cerebralcomplications was no greater than in the group as awhole, and in patients experiencing multiple attacksno increase in risk was evident. Indeed, the prognosisin individual patients was quite variable. Even in thoseexperiencing attacks which were multiple, ofprolonged duration, present for a considerableperiod, or were bilateral, spontaneous remission ofsymptoms without treatment sometimes occurred.

In the group of patients under the age of 50 years,females predominated. Although it is possible thataetiological factors other than atheromatous vasculardisease might account for symptoms in a proportion,over one third experienced TIA and somewhat underhalf had either proximal carotid atheroma sufficientto justify endarterectomy, or complete carotidocclusion. In women, amaurotic attacks might arisethrough migraine or hormonal drug ingestion butonly one of 10 women was taking an hormonalcontraceptive and in no patient was migraineconsidered a likely explanation.The high incidence of carotid arterial disease in

patients with amaurosis fugax was confirmed byangiography. Only 210% of patients undergoingangiography showed no abnormality or only minimalvessel wall irregularity. The remainder all showedatheromatous irregularity, stenosis or completevessel occlusion at some part of the carotid circulationand the range of angiographic abnormalities wassimilar to that found by others.6-8 The likelihood ofa lesion in the region of the proximal internalcarotid artery was increased if the patient displayed alocalised carotid bruit, had an associated history ofTIA or stroke, was hypertensive or was in the olderage group and this experience is similar to thatreported by Wilson and Ross Russell.7

S

Emboli arising from proximal internal carotidlesions may cause symptoms by entering the ophthal-mic or cerebral circulations and this is the rationalebehind treatment by carotid endarterectomy. In thepatients who had complete occlusion of the internalcarotid artery symptoms may have been produced bydifferent mechanisms. Emboli may arise from thestump of the internal carotid artery to enter theexternal carotid artery and travel to the eye or brainby collateral vessels.9 10 Patients who, in addition tointernal carotid occlusion, have disease in theexternal carotid may develop symptoms whenemboli arise from the external carotid artery itself."Retrograde flow through the ophthalmic artery mayresult in ophthalmic "steal" when this vesselprovides an anastomotic channel by which theexternal carotid circulation is able to supply thedistal internal carotid artery to bypass an occlusion.In the two patients in whom the ophthalmic arteryfailed to fill on angiography, symptoms may havearisen as a result of diminished flow through thevessel or by embolisation from an ophthalmic arterialstenotic lesion.12

Because of the clinical and radiological differencesbetween patients treated medically and those treatedsurgically no attempt was made in this study tocompare the outcome of patients in different treat-ment groups. In the patients treated by surgery anexcellent result, with relief of all symptoms, wasachieved in just over half (11 of 20 patients) andimprovement in symptoms occurred in a further threepatients. In just under one third of the surgical group(six patients) the long term results were less satis-factory, although only one patient was permanentlyworse as a direct consequence of surgery. Two ofthese patients experienced no change in symptomsand three patients developed a stroke at some laterdate. The three patients who developed late strokewere poor risk cases. In one of them, endarterectomywas undertaken on the side contralateral to acarotid occlusion. In another, severe additionaldisease in the carotid siphon was not able to betreated surgically and may have been responsible forlater stroke. The third patient had been treated byextracranial-intracranial anastomosis for what hadbeen thought to be an internal carotid occlusion.Review of the angiogram, however, indicated that aproximal internal carotid stenosis, although critical,was not in fact complete and carotid endarterectomywas probably the primary procedure of choice. Thiscase does emphasise the importance of detailedexamination of serial films of the entire angiographicseries in patients with apparently complete internalcarotid occlusion.The one patient who was rendered worse

immediately following surgery had a high grade

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stenosis of the proximal internal carotid and lesionssuch as this carry a risk of complete thrombosis bythe time surgery is performed. In the two patientswho sustained minor cerebral vascular complicationsfollowing surgery the recovery was complete withintwo weeks.The fact that three of the 20 patients who under-

went surgery experienced a late stroke might castdoubt on the efficacy of endarterectomy as aprophylactic measure. However, as already men-tioned, these three patients had extensive disease.This experience emphasises the importance ofcareful patient selection before surgery is recom-mended. Patients who have a critical stenosis ofthe proximal internal carotid, contralateral carotidocclusion, disease of the distal carotid circulation, orwho have atheromatous disease in both carotidcirculations probably carry a much greater surgicalrisk. It is in these cases in particular that increasedrisks must be carefully weighed against the risksinherent in the disease itself. However, in patientswith relatively focal atheromatous disease confinedto one proximal internal carotid, our experiencesuggests that a significant proportion will have theirsymptoms abolished at an acceptably low risk.

We are grateful to the physicians and surgeonswho referred the patients to us, and to Professor GTaylor and to Mr J Lumley who were responsible forthe surgery.


References

Fisher CM. Transient monocular blindness associatedwith hemiplegia. Arch Ophthalmol 1952;47:167-203.

2 Gunning AJ, Pickering GW, Robb-Smith AHT, RossRussell R. Mural thrombosis of the internal carotidartery and subsequent embolism. Q J Med 1964;33:155-95.

3Marshall J, Meadows S. The natural history ofamaurosis fugax. Brain 1968 ;91 :419-53.

4Ehrenfeld WK, Hoyt WF, Wylie EJ. Embolization andtransient blindness from carotid atheroma. ArchSurg 1966;93 :787-94.

5Mungas JE, Baker WH. Amaurosis fugax. Stroke 1977;8:232-5.

6 Harrison MJ, Marshall J. Indications for angiographyand surgery in carotid artery disease. Br Med J1975 ;1 :616-8.

7Wilson LA, Ross Russell RW. Amaurosis fugax andcarotid artery disease: indications for angiography.Br Med J 1977;2:435-7.

8 Eisenberg RL, Main RL. Clinical and arteriographiccomparison of amaurosis fugax with hemispherictransient ischaemic attacks. Stroke 1978;9:254-5.

9 Barnett HJM, Peerless SJ, Kaufmann JCE. "Stump" ofthe internal carotid artery-a source for furthercerebral embolic ischaemia. Stroke 1978;9:448-56.

10 Countee RW, Vijayanathan T. Intracranial embolisa-tion via external carotid artery: report of a case withangiographic documentation. Stroke 1980;11 :465-8.

Burnbaum MD, Selhorst JB, Harbison JW, Brush JJ.Amaurosis fugax from disease of the externalcarotid artery. Arch Neurol 1977;34:532-5.

12 Weinberger J, Bender AN, Yang WC. Amaurosisfugax associated with ophthalmic artery stenosis:clinical simulation of carotid artery disease. Stroke1980;11 :290-3.

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