From sporty little cars to Austin Power's nemesis, society
seems fascinated with all things mini. In the medical
world, mini or lacunar strokes appear to be no exception
— but there's nothing cute about them. Contrary to
what the name implies, mini strokes pack a big punch,
causing memory deficits and even brain damage. Presently,
mini strokes are making headlines because researchers
may have found a novel blood vessel disease that could
turn out to be a significant cause of these events.
Until recently, the prevailing
wisdom concerning intracranial arterial dolichoectasia
— a condition where some of the larger arteries
in the brain elongate and change shape — had been
that it is a non life-threatening complication of atherosclerosis.
An article published online on February 28 in the Annals
of Neurology, however, links dolichoectasia with
aortic aneurysms. The condition may also be associated
with a previously unknown cerebrovascular syndrome or
small vessel disease that leads to mini strokes.
SURPRISING
NEW SYNDROME
"This study is the first to show an association between
intracranial arterial dolichoectasia and the whole spectrum
of small vessel disease abnormalities, thus defining
a new cerebrovascular syndrome," said author Dr Pierre
Amarenco of Bishat University Hospital in Paris in a
public statement.
As part of the Étude du
Profil Génétique de l'Infarctus Cérébral
(GENIC) study, the French researchers used the non-invasive
technique of magnetic resonance imaging (MRI) to examine
510 stroke patients. Sixty-three of these folks had
the brain arterial changes characteristic of dolichoectasia.
They were compared with the remaining 447 stroke patients
who did not have intracranial arterial dolichoectasia.
The comparisons focused on several
features of small vessel disease: the occurrence of
more than one mini-stroke (multilacunar state), interstitial
atrophy of the brain (leukoaraiosis), and a cribiform
state called état criblé that's indicative
of ongoing cerebral congestion.
Compared to stroke patients without
the disease, those with dolichoectasia were more frequently
in a multilacunar state (51% vs 33%). People with this
condition were also more likely to have marked leukoaraiosis
(34% vs 19%) and experience severe état criblé
(32 vs 12%).
SIZE
DICTATES SEVERITY
In fact, the researchers found a direct relationship
between the diameter of the basilar artery — the
cranial artery which is most affected in dolichoectasia
— and the seriousness of small vessel disease.
"If dolichoectasia is present,
[physicians] should look for an associated abdominal
aortic aneurysm and carefully search for associated
cardiac symptoms," advised Dr Amarenco in a public statement.
For the moment, it's not clear
whether dolichoectasia causes or exacerbates small vessel
disease, or whether the two maladies have a common root.
It is known that small blood vessel problems prelude
about a quarter of all mini strokes.
At least 21,000 Canadians suffer
such a transient ischemic attack each year, according
to the Heart and Stroke Foundation of Canada. Depending
on what area of the brain is targeted by a mini stroke,
movement, speech or coordination can suffer. Moreover,
a mini stroke may be a harbinger of a full-blown stroke.
Dr Amarenco and his colleagues
are following the patients in the GENIC study to precisely
peg the genetic or vascular factors associated with
the condition. They are also interested in discovering
whether the present findings can be replicated when
MRI is used to peek inside the corpses of people who
died with dolichoectasia.
Ann Neurol published online
Feb 28, 2005
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