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Case 22 M1 Middle Cerebral Artery Occlusion with Prominent Early Temporal Branch
276
of recurring stroke in the PFO subgroup was 0.6 %. If patients had in addition an ASA the risk increased to 3.8 %.
Patients with absent septal pathology had a risk of 1.1 %
and, interestingly, those with an ASA alone remained without recurring ischemic events (Mas et al. 2001). Because of
the above findings, long-term oral anticoagulation or closure of the combined septal abnormality was considered
to be a therapeutic alternative to aspirin. Contrary to this
assumption, the PFO in Cryptogenic Stroke Study (PICSS),
in which 630 patients, 265 of them with cryptogenic
stroke, were observed over a 2-year period, did not find
a significant superiority of warfarin over aspirin in preventing recurrent stroke. This was independent of the
Degree of Neurosonologic Difficulty: High
presence of a PFO alone, the size of the foramen, or associationwithanatrialseptumaneurysm(Hommaand
Sacco 2002). Recent published data demonstrate a significant association of multiple acute lesions on diffusionweighted MRI in combined ASA and PFO, compared with
PFO alone (Bonati et al. 2006). Although overall data are
inconsistent, the latter finding supports the hypothesis
that combined atrial septal abnormalities may have an
important role in the pathogenesis of recurrent stroke
(Bonati et al. 2006). From a neurologic point of view it
seems actually obvious that treatments other than aspirin
are only worth considering if a symptomatic patient has
both PFO and ASA. The main alternative to medical treatment is percutaneous closure of the PFO, which has been
performed with increasing frequency in recent years.
Many device systems have been developed and are currently available. Successful closure can be achieved in 98 %
of cases (Windecker et al. 2000). A retrospective review of
studies published since 1990 and including reports of
about 1430 symptomatic patientsyielded an annual stroke
risk of 0.19 % and a combined risk of stroke and death of
1.15% after percutaneous closure of a PFO. Interventionrelated severe complications such as death, a life-threatening bleed, embolic events, or cardiac tamponades occurred in 1.5% of patients. Complications such as arrhythmias, device arm fracture, device embolization, and device
thrombosis were reported in 7.9 % of cases. Compared with
thesenumbers,theannualstrokerateinagroupof943
medically treated symptomatic patients was 1.98 %, with a
combined annual rate of stroke and death 3.12 % (Homma
and Sacco 2005). However, there are no randomized trial
data on comparison of medical treatment with percutaneous closure of the PFO and no clear evidence-based
recommendations can be given. Therapeutic decisions
shouldthereforebebasedonindividualriskfactorssuch
as age and family history of thrombophilia. In cases with
PFO alone it seems reasonable to start with aspirin and to
wait for the results of large ongoing studies such as the
CLOSURE-1, Randomized Evaluation of Recurrence Stroke
Comparing PFO Closure to Established Current Standard of
Care Treatment (RESPECT), and the percutaneous closure
(PC)-Europe Trial. In recurrent stroke, oral anticoagulation
or interventional closure may be alternative options.
In our present case of cryptogenic stroke in a young
patient, a PFO without accompanying atrial septum aneurysm was present. A cardiac embolus or paradoxical embolic event seemed possible but was not proved. The final
decision to close the PFO was a result of an extended
ambulatory cardiologic consultation with the patient and
was finally done on the request of the patient herself. From
a neurologic point of view, there was no indication for
interventional closure of the PFO. Postinterventional follow-up information has not been available to us.
Our patient also experienced migraine with aura. Migraine, PFO, and their potential relation to ischemic stroke
has been subject of intensive research and is controversial.
The prevalence of PFO has been shown to be higher in
cryptogenic stroke patients with migraine than in those
without migraine (Mas et al. 2001). In this study 267 out of
581 young stroke patients (45%) demonstrated a PFO with
orwithoutanASA.WithinthePFOgroup,27.3%had
migraines compared with 14 % of patients in the group
without a PFO.
Migraine itself can be associated with ischemic stroke.
Three retrospective case–control studies found an increased relative risk of stroke ranging from 3.8 % to 8.4 %
in women aged less than 45 years who had migraine with
aura (Chang et al. 1999, Donaghy et al. 2002, Tzourio et al.
1995). This risk is tripled if migraine and smoking are
combined, and quadrupled if migraine and the oral contraceptives are combined. However, retrospective studies
probably overestimate the real risk of stroke. A comparative study that analyzed retrospective and prospective
data found a twofold higher risk in the retrospective
than the prospectively collected data (Stang et al. 2005).
Over all, and in comparison with the classic risk factors of
stroke, the migraine-related absolute risk of stroke is very
low. In epidemiologic studies the estimated attributable
risk ranges between 18 to 40 additional annual ischemic
strokes per 100 000 women (Kurth et al. 2005, Tzourio et
al. 1995). The underlying pathomechanism of migrainous
stroke is unclear. A possible hypothesis is a severe state of
hypoperfusion during a migraine attack. However, most
ischemic strokes in migraine patients occur within the
headache-free interval (BousserandWelch2005).Inour
patient, migrainous stroke was unlikely as she denied
headaches during stroke evolution.
Finally, migraine has also been related to PFO in several
case–control studies. In patients with migraine with aura
the prevalence of PFO was found to beup to 54 % compared
with 16 % in patients without aura. The latter corresponds
well to the reported prevalence of 24 % within a normal
healthy population (Lamy et al. 2002, Diener et al. 2007).
There is actually considerable debate about the usefulness
of endovascular closure of PFO in patient with migraine. A
recommendation to perform a closure cannot be based on
the currently available data.
Discussion
277
Angiologic and Anatomic Aspects
Transesophageal echocardiography is the current gold
standard for PFO diagnosis. Indirect diagnosis can also be
made by TCD analysis. The combination of both methods
yields a sensitivity and specificity of 100 %, compared with
autopsy findings (Schneider et al. 1996) (for further general information about TCD diagnosis of persistent foramen ovale and embolus detection, see Chapter 4, “Patho-
genesis of Stroke,” p. 64).
The anatomic peculiarity of our case is the early temporal MCA branch, which led to an initial misinterpretation of
the transcranial color-coded sonography (TCCS) findings.
Instead of the M1-MCA segment, a strong temporal MCA
branch was visualized over a more basal course along the
lesser wing of the sphenoid bone. In view of the low flow
velocities though otherwise normal flow profiles, a distal
occlusive process was suspected. According to the TIBI
classification, our finding correspond to a type 3 flow
pattern (see also Chapter 5, “Intracranial Pathology,”
p. 94). Our initial report 1 day following thrombolysis
read as: “successful M1-MCA recanalization after systemic
thrombolysis, with indirect signs of distal MCA branch
occlusion.” In the TCCS control, 10 days later, again a distinct MCA asymmetry was apparent. The unaffected side
followed a straight course whereas the affected side demonstrated only a punctuated and a far more basal MCA
visualization. This, in combination with the knowledge
that MCA vessel courses are usually not relevantly bilaterally asymmetric in young subjects led to the correction
of our ultrasound report toward a persisting M1-MCA
occlusion of its middle segment and visualization of an
early temporal MCA branch (which had become more
prominent due to the main stem MCA occlusion and the
required collateral effort). Both of the above findings were
confirmed by DSA, which demonstrated the linear MCA
course on the left, the persisting M1-MCA occlusion on the
right side, as well as the more basal course of its early
temporal MCA branch (see Figs. B22.17, B22.18).
It is therefore important to start TCCS insonation on the
presumed unaffected side to get a general idea of vessel
course and flow profiles. Itis equally important to consider
the insonation planes that have been used. If a clear midbrain plane had been used, the basal temporal MCA branch
would not have been seen as it usually runs in the upper
pontine plane. Remarkably, the extracranial ICA flow was
not relevantly impaired as could have been expected in
proximal M1-MCA occlusion. This was caused by the combination of the strong ipsilateral A1-ACA segment and
early temporal MCA branch as well as the anatomic variant
ofafetal-typePCAonthesideoftheMCAocclusion,allof
them draining blood from the ICA and functioning as
collaterals (see also Case 17, p. 231, and Chapter 5, “Intra-
cranial Pathology,” p. 94).
There are limited reports about the prevalence of early
temporal MCA branches. The angiographic literature accounts for a prevalence of 6 % (Huber 1982) whereas ana-
tomic studies found a small early temporal MCA branch in
48 of 50 autopsy-investigated hemispheres (Gibo et al.
1981). A more recent publication confirmed this finding
and reported the presence of an early temporal branch in
90 % of hemispheres. The authors also found that the more
proximal the origin, the larger the vessel. These anatomic
findings correlated well with additional post-mortem angiographies (Tanriover et al. 2003). The early temporal
branch has to be differentiated from an early M1-MCA
bifurcation which might occur within the first centimeter
of the MCA main stem. However the latter is rare and only
found in up to 2 % of angiographically studied patients
(Huber 1982). Anatomically, the early temporal branch is
most frequently the temporopolar artery which originates
directly below the lenticulostriate arteries from the M1MCA segment. From there it runs—as also visible in our
patient’s DSA on the unaffected side—in a lateral and more
basal direction (see Fig. B22.17).Reported diameters of the
early temporal branch vary. Gibo and coworkers (1981)
found that the diameter of the early temporal branch did
not exceed 1.5 mm and measured between 1 mm and
1.5 mm in 38 % of cases only. In contrast, the other cortical
MCA branches exceeded 1.5 mm in 50–90 % of cases. Tanriover and coworkers (2003) found a mean diameter of
1.4 mm. It remains unclear how often the early temporal
MCA branch may be observable on routine TCCS examination. However, in cases of M1-MCA occlusion it can be
assumed that visualization will become easier because of
its additional collateral function. Its presence contributes
the greatest risk for overlooking a middle or distal M1MCA occlusion even if TCCS is used, and special attention
should be paid. Differentiation by TCD is probably impossible.
The observed MCA main stem occlusion persisted over
at least 11 days and permitted a comparison of the MRA,
CTA, and DSA, which had been performed within this
period. The initial CTA findings were interpreted as a proximal M1-MCA main stem occlusion and the well-demarcated insular branches were thought to be perfused in a
retrograde manner. Only after critical comparison with the
DSA images, which demonstrated the early temporal MCA
branch,wasthisvesselvisualizedbyCTA.Asaconsequence, it can be concluded that CTA sensitivity is suffi
cient but the attention of the evaluating examiner has to
focus on the potential collateral pathways. In comparison,
TOF MRA did neither visualize the temporal MCA branch
nor the insular branches. DSA remained to be the most
convincing method in our case as branch visualization as
well ascollateral function was easily assessable(for further
discussion on angiologic aspects of intracranial occlusion,
see Case 10, p.176).
Finally the persisting MCA occlusion over more than 11
days needs to discussed. The reported rates of general
recanalization after thrombolysis vary. In a series of 31
patients, in about 50 % of them undergoing thrombolysis,
26 % recanalized within 24 hours. After 3 days, 65 % of the
MCAs were reperfused (Ringelstein et al. 1992). An almost
Degree of Neurosonologic Difficulty: High
-
Case 22 M1 Middle Cerebral Artery Occlusion with Prominent Early Temporal Branch
278
similar range of 62.5 % was found in a group of 16 patients
without thrombolysis after several weeks. Only 38 % recanalized within the first week (Kaps et al. 1992b). In an
observational TCD study of 50 patients with a M1-MCA
occlusion, reopening was observed in 86 % patients within
2 weeks (Alexandrov et al. 1994). In intravenous thrombolysis, recanalization of eight MCA main stem occlusions
wasseenin50%withinthefirst2hoursandin75%after
24 hours (Gerriets et al. 2000). With regard to the etiology
Degree of Neurosonologic Difficulty: High
of MCA occlusion and recanalization patterns, Molina and
coworkers (2004) reported a significantly faster 1- and 6hour recanalization rates of 59 % and 76%, respectively, in
cardiac embolism, compared with 8 % and 33 % in arteryto-artery embolic occlusion if rt-PA treatment was given. It
is notable that in our patient the MCA occlusion remained
for at least 11 days despite intravenous thrombolysis and a
suspected cardiac embolism.
Case 23
Takayasu Arteritis with Subclavian Artery and
Vertebral Artery Stenoses
279
Clinical Presentation
A32-year-oldTurkishmanwasadmittedwithanepisode
of unconsciousness that lasted about 2 minutes, whichwas
then followed by nausea and vomiting. He complained
about worsening of his visual acuity in the preceding 3
days. Several years prior to this event he had sustained a
similar episode of unconsciousness that at the time was
considered to be due to orthostatic dysregulation. At that
time, no neurologic examination or cerebral imaging had
been performed. The patient had no vascular risk factors
and no relevant past medical history. On neurologic examination, he had left complete and right partial homonymous hemianopia (National Institute of Health Stroke
Scale [NIHSS] score 3). In addition, asymmetric radial
pulses were noted.
Initial Neuroradiologic Findings
Magnetic resonance imaging (MRI) showed bilateral subacute occipital ischemic brain lesions in the posterior cerebral artery (PCA) territory (Fig. B23.1). Magnetic resonance angiography (MRA) was not performed.
Suspected Diagnosis
Transient “top of the basilar” syndrome with incomplete
cortical blindness caused by bilateral infarction in the PCA
territory.
Questions to Answer by Ultrasound Techniques
• Was there evidence of pathologic change in the vertebrobasilar system?
• If so, was it of atherosclerotic or vasculitic origin?
Initial Neurosonologic Findings
Extracranial Duplex Sonography
There was no evidence of atherosclerotic or vasculitic
changes in the carotid arteries. The vertebral arteries
(VAs) revealed normal calibres (left: 4.5 mm, right:
3.9 mm). The left VA presented a poststenotic flow pattern
with delayed systolic flow increase and reduced flow velocity in its V2 segment. At its origin an increased flow
reaching 246 cm/s peak systolic flow velocity was detected. The left subclavian artery (SA) was not visualized.
Doppler spectrum analysis of the right V2-VA segment
revealed alternating, mostly retrograde flow. Muscular
activity ofthe right arm led to an increaseof the retrograde
flow component. The right SA was not detectable
(Figs. B23.2–B23.5). A normal triphasic flow signal was
seen in the left brachial artery. The right brachial artery
revealed a poststenotic flow pattern with a monophasic
flow signal and reduced pulsatility (not shown).
Transcranial Duplex Sonography
Normal findings were seen in both anterior and middle
cerebral arteries. Both PCAs were visible but presented a
marked poststenotic flow pattern in all segments with a
bandlike nonpulsatile flow and reduced flow velocities.
Transforaminal insonation revealed a mildly poststenotic
flow pattern in the left V4-VA segment and alternating
flow in the right V4-VA segment. The basilar artery (BA)
was not visualized (Figs. B23.6–B23.9).
Conclusion
Proximal high-grade stenosis of the leftVA and right-sided
incomplete subclavian steal syndrome (grade 2) indicating
high-grade stenosis or occlusion of the proximal right SA.
In addition, marked hemodynamically compromised flow
in both PCAs indicating no relevant collateralization from
the anterior circulation via the PcoA.
Conventional Angiography
Emergency digital subtraction angiography (DSA) was performed shortly after ultrasound examination and demonstrated a proximalshort high-grade stenosis of the right SA
proximal to the origin of the VA. The right VA was not
visualized, but a high-grade stenosis at the origin of the
left VA with collateral vessels in its vicinity was observed.
NofurtherobstaclewasseenintheleftintracranialVAand
intheBA.TheflowinbothPCAsappeareddiminished,
without signs of obstruction. Both carotid arteries were
regular but no collateral flow via one or both PCoAs was
Case 23 Takayasu Arteritis with Subclavian Artery and Vertebral Artery Stenoses
280
detectable. Both renal arteries were normal (Figs. B23.10–
B23.12).
Clinical Course (1)
An artery-to-artery embolic event from the proximal left
VA stenosis was thought to be the cause of the cerebral
ischemia. An atherosclerotic etiology was considered unlikely because of the angiographic and ultrasound findings, the young age of the patient, and the lack of vascular
risk factors. Infectious diseases were ruled out by laboratory tests and analysis of the cerebrospinal fluid (CSF).
Degree of Neurosonologic Difficulty: High
However, mild anemia, an increased erythrocyte sedimentation rate (ESR) of 47 mm/hr, a C-reactive protein (CRP)
level of 10 mg/L (normal < 5mg/L), and the involvement of
the proximal vessel segments were suggestive of Takayasu
arteritis. Long-term therapy with oral steroids (75 mg
prednisolone daily) and antiplatelet therapy with aspirin
was commenced. Six months later the patient was admitted for follow-up examination, and ultrasound imaging.
Question to Answer by Ultrasound Techniques (6 Months)
• Was there evidence of stenosis regression after the steroid treatment?
Neurosonologic Findings (6 Months)
Clinical Course (2)
With long-term treatment with oral steroids, the ESR normalized and no further ischemic events occurred. However, ultrasound suggested further progression of the
right-sided SA disease. High-dose intravenous cortisone
therapy was administered for 5 days, but this did not
improve the vascular status. Considering the progression
of vascular pathology regardless and the absent PCoA on
both sides, it was decided to perform a right carotid–sub-
clavian bypass connecting the common carotid artery
(CCA) with the SA distal to the SA stenosis but proximal
to the origin of the VA to improve the posterior circulation.
The surgery proceeded uneventfully and medication for
long-term stroke prevention was subsequently continued
with aspirin. No interventional treatment was considered
for the left-sided proximal VA stenosis, which remained
stable. Afterwards, the patient clinically remained in remission without laboratory evidence of inflammatory activity. Therefore, corticosteroid treatment was discontinued. The patient was reviewed 2 months postoperatively.
Questions to Answer by Ultrasound Techniques (8 Months)
• Was the bypass patent?
• If so, was there orthograde blood flow in the right VA?
• Had the blood flow in the BA and both PCAsnormalized?
• Were there any hemodynamic changes in the left VA?
Extracranial Duplex Sonography
Identical flow patterns were seen in the left V1- and V2-VA
segments (not shown). The right V2-VA segment now
presented a completely retrograde flow pattern (Fig.
B23.13). An assessment of the SA was again not possible.
Transcranial Duplex Sonography
Unchanged prominent poststenotic flow patterns were
seen in both PCAs. On transforaminal insonation, the left
V4-VA segment also appeared almost unchanged, but the
right V4-VA segment now demonstrated a continuous
retrograde flow. The BA was not visualized (not shown).
Conclusion
Unchanged long-segmented stenosis at the origin of the
left VA. Worsening right-sided subclavian steal (grade 3),
probably due to progressive stenosis or occlusion of the
right SA.
Neurosonologic Findings (8 Months)
Extracranial Duplex Sonography
Flow in the left VA remained unchanged. The bypass was
not visualized, but normal and orthograde flow signals
were found in the right V2-VA segment (Fig. B23.14).
Transcranial Duplex Sonography
Both PCAs presented normalized flow signals (not shown)
while the left V4-VA segment was unchanged. The right
V4-VA segment, now revealed an almost normalized orthograde flow (Fig. B23.15).
Conclusion
Complete normalization of flow in the right VA with no
signs of the subclavian steal following carotid–subclavian
bypass. Unchanged flow pattern in the left VA origin, indicating stable proximal high-grade VA stenosis.
Final Diagnosis
Bilateral PCA infarcts caused by artery-to-artery embolism
from a left V0-VA stenosis in Takayasu arteritis. Right sub-
Final Diagnosis
clavian steal syndrome (grade 3) with markedly compromised posterior circulation in bilateral hypofunctional
PCoA. Improved perfusion of the vertebrobasilar circulation after right-sided carotid–subclavian bypass.
281
Degree of Neurosonologic Difficulty: High
Fig. B23.1 MR T2-weighted image, axial plane. Note right-pro-
nounced bilateral subacute PCA territorial infarctions (arrowheads).
Fig. B23.3 Extracranial duplex, longitudinal plane. Increased flow in
the proximal left V1-VA segment (angle-corrected flow velocity:
246/106 cm/s).
Fig. B23.2 Extracranial duplex, longitudinal plane. Reduced flow
velocity and pulsatility, suggesting a poststenotic flow pattern in
the left V2-VA which shows a normal diameter of 4.5 mm (flow
velocity: 36/16 cm/s).
Fig. B23.4 Extracranial duplex, longitudinal plane. Alternating, but
almost retrograde flow in the right V2-VA with a normal diameter of
3.9mm(flowvelocity:40/0cm/s).
Case 23 Takayasu Arteritis with Subclavian Artery and Vertebral Artery Stenoses
282
Degree of Neurosonologic Difficulty: High
Fig. B23.5 Extracranial duplex, longitudinal plane. Complete retro-
grade flow in the right V2-VA after muscular activity of the right arm
(flow velocity: 60/20 cm/s).
Fig. B23.7 TCCS (transforaminal approach). Alternating flow in the
right V4-VA (flow velocity: -10/15 cm/s).
Fig. B23.6 TCCS (transforaminal approach). Mildly poststenotic flow
pattern in the left V4-VA (30/10 cm/s).
Fig. B23.8 TCCS (transtemporal approach), left-sided insonation,
midbrain plane. Severe poststenotic flow pattern with a bandlike
flow in the left P1-PCA (flow velocity: 30/25 cm/s).
Fig. B23.9 TCCS (transtemporal approach), right-sided insonation,
midbrain plane. A similar severe poststenotic flow pattern was
present in the right proximal P2-PCA (flow velocity 34/20 cm/s).
Final Diagnosis
283
Degree of Neurosonologic Difficulty: High
Fig. B23.10 DSA, selective right brachiocephalic injection, poste-
roanterior view. Proximal short high-grade stenosis of the right SA
(arrow) proximal to the origin of the VA. Note, that there is no
contrast filling of the right VA due to alternating, mostly retrograde
VA flow, and this must not be confused with VA occlusion.
Fig. B23.11 DSA, selective left SA injection, posteroanterior view.
Long-segmented left proximal irregular high-grade VA stenosis (arrows). Note the collateral vessels in the vicinity.
Fig. B23.12 DSA, selective left VA injection, posteroanterior view.
Faint vessel contrast within both PCA territories (arrows).
Fig. B23.13 Extracranial duplex, longitudinal plane. Six months follow-up: Worsening of flow in the right V2-VA—completely retro-
grade flow pattern (flow velocity: 37/12 cm/s).
Case 24 Takayasu Arteritis with Subclavian Artery and Vertebral Artery Stenoses
284
Degree of Neurosonologic Difficulty: High
Fig. B23.14 Extracranial duplex, longitudinal plane. Eight months
follow-up: Normalized and orthograde flow in the right V2-VA after
right-sided carotid-subclavian bypass (flow velocity: 70/33 cm/s).
Discussion
Clinical Aspects
Here we report of a 32-year-oldTurkish man with bilateral
PCA infarctions. The underlying cause was a complex pathology within the vertebrobasilar vascular system. A
high-grade proximal SA stenosis on the right side initially
resulted in an incomplete subclavian steal (grade 2) that
over time progressed to a complete steal grade 3 (for
further discussion on clinical findings in subclavian steal,
see also chapter 5, p. 76 and Case 28, p. 319). An additional
left stenosis at the VA origin led not only to bilateral
posterior infarction but also a distinct impairment of the
posterior circulation. The etiology of a bilateral occlusive
disorder of the proximal posterior circulation is mostly
atherosclerotic, but other causes such as traumatic injury,
emboli, or inflammatory diseases such as Takayasu arteritis might also lead to proximal SA obstruction and subsequent subclavian steal. The young age of our patient, the
absent atherosclerotic vessel wall changes, and the involvement of the proximal arteries close to the aortic
arch, in combination with the raised ESR and CRP, were
suggestive of Takayasu arteritis.
Takayasu arteritis is a chronic, large vessel vasculitis of
unknown etiology that predominantly affects the aorta
and its main branches. It is a rare condition with three in
1000000casesperyearinEuropeandNorthAmerica
(Arend et al. 1990). It most frequently occurs in young
Asian woman although it can affect individuals from other
racial backgrounds and age groups. Infectious, autoimmune, and hereditary factors have been discussed previously (Noris2001). In up to 85 % of cases,the SA isinvolved.
The renal arteries are also frequently affected (70 %), followed by the descending aorta (60 %), the carotid arteries
(45 %), the mesenteric arteries (35 %), and the ascending
aorta (30 %) (Procter and Hollier 1992). In contrast to giant
Fig. B23.15 TCCS (transforaminal approach). Eight months followup: Normalized orthograde flow signal in the right V4-VA (flow
velocity: 30/15 cm/s).
cell arteritis, involvement of the intracranial arteries is
extremely rare (Nasu 1975). Sometimes the pulmonary
and coronary arteries are also involved. Within these vessels, the disease might progress to stenoses, occlusions, or
to the development of aneurysms. The clinical manifestation depends on the location and extent of the affected
vessels as well as the activity of the inflammation.
In the early stages of the disease, vascular symptoms
may be completely absent. Patients often complain of
fatigue, weight loss, and subfebrile temperatures. Laboratory analysis often reveals anemia as a sign of chronic
disease as well as pathologically altered values of nonspecific markers of inflammation (raised ESR, CRP, a2globulin and hypoalbuminemia). The leukocyte count is
usually normal (Kerr 1995).Later on, stenosis,occlusion, or
dilatation of affected vessel segments might lead to a
variety of clinical symptoms. Visual disturbance such as
blurred vision, diplopia, and amaurosis fugax are found in
up to one- third of cases, and ischemic stroke is observed in
5–14% of patients (Procter and Hollier 1992).
Diagnosis is based on the criteria of the American College of Rheumatology (ACR). Three of the following six
criteria must be present:
1. Onsetatage≤ 40 years.
2. Claudication of an extremity.
3. Decreased brachial artery pulse.
4. Greater than 10mmHg difference in systolic blood
pressure between the right and left arms.
5. A bruit over the subclavian arteries or the aorta.
6. Arteriographic evidence of narrowing or occlusion of
the entire aorta, its primary branches, or large arteries
in the proximal upper or lower extremities.
Applying the above criteria, sensitivity and specificity are
90.5 % and 97.8%, respectively (Arend et al. 1990). Laboratory findings may further support the diagnosis. Because
the large proximal arteries are predominantly involved, a
Discussion
285
confirmatory biopsy, as would usually be performed in
giant cell arteritis, is generally not possible.
Treatment of Takayasu arteritis consists of administration of corticosteroids. Early drug treatment results in an
improvement of systemic symptoms, normalization of
laboratory parameters, and a complete halt of the inflammatory process (Kerr 1995). In patients in whom inflammation reoccurs once the steroid dose is reduced, who
cannot tolerate steroids due to side effects, or in whom
steroids fail to work, other immunosuppressive agents
such as methotrexate, azathioprine, or cyclophosphamide
may be used. About 50 % of patients do not sufficiently
respond to treatment with steroids alone (Kerr 1995). A
more recently proposed therapeutic approach is the use of
tumor necrosis factor-a (TNF-a) antibodies (Seko 2007).
In cases with stenosis or occlusion, additional endovascular or surgical interventions might become necessary.
These, however, should only be considered if the vascular
changes are symptomatic. Depending on the affected vascular segments, surgical intervention with insertion of a
bypass is demonstrating good success rates. Compared
with bypass operations for atherosclerosis, however, bypass-stenoses are more frequently observed (Giordano et
al. 1991).
An analysis of the patency of carotid-subclavian bypasses inserted for subclavian steal syndrome in a nonspecified patient group showed good technical and clinical
results. Ten years after insertion, the primary and secondary patency was 92 % and 95 %, respectively. The 30-day
morbidity was 6 %. There were no perioperative strokes or
deaths (AbuRahma et al. 2000). An important alternative
to the surgical approach is intravascular balloon dilatation
and placement of endovascular stents. There are no systematic reports on the interventional management of Takayasu arteritis. Single case reports suggest good technical
results. In patients with atherosclerosis, a primary technical success rate of 84 % and a secondary cumulative patency rate of 72% after 100 months were reported (Korner
et al.1999). With regard to the rates of restenosis, the stent
placement method seems to be superior to only balloon
dilatation (Rodriguez-Lopez et al. 1999). However, no longterm follow-up studies or controlled trials have been conducted.
In our case, a right high-grade SA stenosis led to an
ipsilateral subclavian steal syndrome and the left-sided
high-grade VA stenosis to bilateral PCA infarction. This,
in combination with the insufficient collateral blood flow
via bilateral hypoplastic PCoAs led to distinct hemodynamic impairment in the posterior circulation. Revascularization to improve this constellation seemed to be the
best therapeutic approach, and a carotid–subclavian by-
pass was performed. Postintervention, flow profiles in the
posterior circulation markedly improved and the inflammatory activity declined. The symptomatic left-sided VA
stenosiswastreatedmedicallybyantiplateletagent.
Angiologic and Anatomic Aspects
Besides the above mentioned clinical signs, the main diagnostic criterion of Takayasu arteritis is the typical angiographic topography of the vascular lesions. Angiography,
however, cannot visualize the vessel wall and therefore
vessel wall thickening may be overlooked if it does not
lead to obvious vascular lumen reduction in early phasesof
the disease (Schmidt et al. 2002b).
In contrast, extracranial ultrasound is an excellent technique tovisualize evendiscrete vesselwall alterations. The
typical finding in Takayasu arteritis is a homogeneous,
mid-echogenic vessel wall thickening often associated
with stenosis or occlusion (see also chapter 5, “Ve sse l
Wall Pathology,” p. 76). Although similar to the findings
in giant cell arteritis, the vessel wall changes in Takayasu
arteritis are slightly more clear and therefore called “macaroni phenomenon” (Schmidt 2004). However, the assessment of inflammatory vessel wall pathology in SA and VA
is more difficult than in the CCA. In our patient, the CCA
wasnotaffected,whichexplainstheabsenceofthetypical
ultrasound findings. Although atherosclerotic vessel wall
changes appear distinctly different from vasculitic
changes, both may coexist. A number of authors have
indicated that chronic vessel wall inflammation might
lead to premature atherosclerosis (Bacon et al. 2002,
Manzi 2000, Van Doornum et al. 2002). Coexistence of
atherosclerotic and inflammatory changes has also been
reported in Takayasu arteritis (Filer et al. 2001, Numano et
al. 2000a, Numano et al. 2000b). In a series of 30 female
patients with Takayasu arteritis, atherosclerotic plaques
werefoundin27%,butonlyin2%ofanageandsexmatched healthy population. Furthermore, the intima–media thickness was also significantly increased in the
patients with arteritis (0.95 ± 0.31 mm vs. 0.59 ±
0.08 mm) (Seyahi et al. 2006).
Inflammatory vessel wall changes can also be visualized
using MRI. A delayed hyper-enhancement after contrast
administration was observed in seven patients within 20
minutes(Desaietal.2005).Inalargerseriesincluding55
consecutive patients computed tomographic angiography
(CTA) was not only able to detect continuous and segmented vessel involvement but also to differentiate between active and inactive inflammation (Chung et al.
2007).
Our case demonstrates a particular unfavorable hemodynamic constellation of the posterior circulation. A grade
3 subclavian steal was present onthe right side (for further
details of ultrasound assessment of subclavian steal, see
also Case 28, p.319) so that the left VA provided the blood
supply to the posterior circulation as well as to the right
arm via the right VA but was itself hemodynamically impaired by the high-grade stenosis at its origin. Usually in
such cases, collaterals from the ICA via one or both PCoAs
to the PCA, and if necessary to the BA, compensate for this
deficit. Patients with this flow pattern are considered to be
at high risk of subsequent ischemic stroke (de Bray et al.
Degree of Neurosonologic Difficulty: High