WSO December 2023 – Issue 3 - 1187

Mayer-Suess et al.
1187
Keywords
Cervical artery dissection, aneurysm, occlusion, stroke, stenosis, outcome
Received: 5 May 2023; accepted: 9 June 2023
Introduction
The pathogenesis for one of the prime reasons for ischemic
stroke in young adults, spontaneous cervical artery dissection
(sCeAD), remains unclear to date.1,2 It is well known
that the pathognomonic vessel wall hematoma can be
located either subintimally or subadventitially. Subintimal
mural hematomas are believed to be associated with intimal
tear and anterograde blood flow from the vessel to the false
lumen (inside-out theory) resulting in vessel stenosis or
occlusion, while subadventitial sCeAD may arise from rupture
of the vasa vasorum (outside-in theory) and rather lead
to expansive vessel pathologies.3-8 It is tempting to speculate
that these two distinct phenotypes, which can be distinguished
in magnetic resonance imaging (MRI), have
non-identical pathomechanisms that might be reflected by
differences in patient characteristics as well as the longterm
outcome. To date, clinical features and outcomes have
only been assessed in patients with either steno-occlusive
or aneurysmal post-sCeAD pathologies.7-9
Aims and/or hypothesis
It was our goal to investigate whether individuals with
either steno-occlusive or expansive sCeAD-related mural
hematoma in the acute phase differ in clinical characteristics,
functional or imaging outcome, or show clinical signs
of connective tissue disorder. Furthermore, we investigated
whether either one of the types of vessel wall hematomas is
associated with sCeAD recurrence in the long run.
Methods
Patient recruitment, selection, and variable definition
During the ReSect study, each sCeAD patient admitted to
the Department of Neurology of the Medical University of
Innsbruck from January 1990 until December of 2016 was
identified and invited to a standardized outpatient followup
visit, which had to have been at least 1 year after sCeAD
event. sCeAD diagnosis had to be secured through mural
hematoma visualization in T1-fat saturated MRI images at
baseline. Furthermore, known monogenetic tissue disorders
and a timely association to major head/neck trauma
or trauma causing additional signs of separate external or
internal injury were exclusion criteria. For the current analysis,
all available MRI images of ReSect patients were
retrospectively evaluated. To enable group allocation, the
raw magnetic resonance angiography (MRA) images and
T1 fat-saturated MRI sequence at dissection-diagnosis
(baseline) with multiplanar-reconstructions were used.
Individuals were dichotomized as follows: (1) steno-occlusive
hematoma-mural hematoma causing either lumen
stenosis or occlusion without expansion of total vessel
diameter at the dissection site, and (2) expansive hematoma-mural
hematoma causing vessel diameter expansion
without lumen stenosis or occlusion at dissection site
(Figure 1). Vessel and lumen diameter of the dissection site
were compared to proximal, non-dissected sections of the
same artery. A graduation of vessel stenosis was not performed.
The group allocation was performed by one rater
(LM-S). To account for intra-rater variability, a random
sample of 30 ReSect participants was re-rated 4 months
after the initial rating. Patients with single-vessel sCeAD
causing simultaneous stenosis and diameter expansion as
well as those with multiple-vessel sCeAD with both traits
being evident were excluded. Variables used for detailing
patient and sCeAD characteristics were defined as follows:
(a) ischemia was a composite variable encompassing transient
ischemic attack and ischemic stroke; (b) vascular risk
factors were assessed in accordance with current guidelines;10,11
(c) comorbidities were identified through patient
history taking and retrospective chart review; (d) family
history was reserved for first-degree relatives; (e) patients
with multiple single-time point sCeAD had more than one
cervical artery dissected at dissection diagnosis (baseline);
and (f) symptom to diagnosis was defined as the duration
between perceived symptom begin as stated by each patient
to MRI-based visualization of the mural hematoma. The
ReSect-study-specific follow-up included a detailed patient
history taking, 3T-whole-body contrast-enhanced MRI, and
a structured clinical examination. The examination included
the National Institutes of Health Stroke Scale (NIHSS),
Barthel Index, modified Rankin Scale (mRS), and an
assessment of potential clinical stigmata for connective tissue
disorders, which were done by an experienced dermatologist
and mirrored the investigation proposed by Dittrich
et al.12 Missing values were completed through retrospective
chart review of all available electronic medical files. At
follow-up, the raw MRA images and T1 fat-saturated
sequence of the study-specific 3T-MRI were used to assess
residual vessel pathologies. Further details on the ReSect
study have already been published.13-17
Statistical methodology
IBM SPSS Statistics 27 was used for the statistical analysis.
Differences in categorical or continuous variables were calculated
using Pearson chi-square or Mann-Whitney U test,
respectively.
International Journal of Stroke, 18(10)
WSO December 2023 – Issue 3

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