Page 11 - Revista SPORL - Vol 58. Nº2
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TABLE 2
Characteristics of patients with stroke after SHL.
Patient Gender Age Affected ear SHL Stroke Evolution time (yr) Stroke subtype a
1 Male 2002 6 SAO
2 Male 73 Right 1996 2004 10 LAA
3 Female 2014 6 SIC
4 Female 90 Bilateral 1994 2011 8 SAO
5 Female 1995 1 CE
6 Male 46 Left 2008 2015 20 SAO
7 Male 2011 14 SAO
88 Bilateral 2003
75 Right 1994 ARTIGO ORIGINAL ORIGINAL ARTICLE
57 Left 1995
69 Left 1997
aAccording to Lausanne Stroke Registry classification10: LAA, large-artery atherosclerosis; CE, cardioembolism; SAO, lacunar stroke or
small-artery occlusion; SIC, stroke of other infrequent cause.
stroke (secondary outcome analysis). All of the patients increase the risk of stroke during the observation time
included in the secondary outcome analysis presented period of 6 years.
some cardiovascular disease risk factors (Figure 1). Table In the present study stroke was reported between 1
1 shows the clinical characteristics and comorbidities and 20 years after SHL. Therefore, the risk for a stroke
in patients with SHL in different series and the present remains for several years after an episode of SHL. Two
study. Stroke was reported in 21 patients: 7 (10.94 %) patients with bilateral SHL had a stroke during follow-
of the SHL patients and 14 (5.46 %) from the control up. Conversely, none of the patients with bilateral SHL
cohort. SHL patients had significantly lower stroke- experienced a stroke in Chang et al. study6.
free survival rates than de control subjects (p < 0.01).
According to Lausanne Stroke Registry classification 10, Although the mechanisms responsible of the
lacunar stroke or small-artery occlusion (SAO) was the relationship between SHL and the subsequent stroke
most frequent form of stroke presentation. have to be elucidated, elevated plasma fibrinogen and
The majority of cases occurred within the first 10 years cholesterol could have a role since they can contribute
after SHL, although two cases occurred at 14 and 20 to atherosclerosis and thrombosis19,20. Cholesterol may
years. Two patients with bilateral SHL had a stroke impair cochlear vascularization by reducing the release
during follow-up (Table 2). of nitric oxide from endothelial cells and it can also
diminishes motility of outer hair cells21. Since fibrinogen
DISCUSSION increases plasma viscosity and induces aggregation
The present study try to consider the risk of stroke within of erythrocytes, thrombocytes, and leucocytes, it
patients in the long-term follow-up after hospitalization may also reduce cochlear blood flow22. Fibrinogen/
for an acute SHL episode. LDL apheresis has been reported to be effective in
Age above 65 years, hypertension, coronary artery treatment of SHL since it may reduce the concentration
disease, and history of stroke have been reported as risk of serum LDL, lipoprotein and fibrinogen23. Glycoprotein
factors for stroke after SHL5-8. These are also risk factors polymorphisms associated to elevated fibrinogen
for stroke in the general population11,12. Patent foramen concentration have been reported in SHL patients24. The
ovale has also been suggested as a cardiovascular risk C807T glycoprotein polymorphism has proved to be a
factor associated with stroke and SHL13-18. risk factor for SHL and stroke19,25,26.
Previous studies reported that the probability of stroke The inner ear is especially sensitive to ischemia.
was 1.64 times5, 2.02 times7 and 1.22 times8 higher Impaired blood flow in the labyrinthine artery is
in SHL patients. Moreover, 12.7% of the SHL patients regulated by plasma viscosity and adrenergic receptors.
had a stroke and almost 50% of patients presented Studies suggest a vascular origin in SHL27. Some authors
stroke within 2 years after the SHL5. Kim et al.7 found found a high incidence of cardiovascular risk factors in
that SHL was associated with increased incidence of their sample28. However, the lack of a clear relationship
cardiocerebrovascular disease, specifically stroke. Kim between SHL and cardiovascular risk factors might
et al.8 found that SHL increased the risk of ischemic suggest a multifactorial origin28.
stroke, but not hemorrhagic stroke. The small number of patients affected by SHL of unknown
However, other studies concluded that SHL did not cause who presented cardiovascular disease risk factors
increase the risk of stroke. Chang et al.6 divided SHL is a limitation in the present study. Data from this study
patients into a stroke group and a non-stroke group and suggest a vascular origin of SHL of unknown cause in
its features were compared but there is not a control a group of patients with subsequent development of
group. Ciorba et al.11 found that SHL did not significantly stroke in a small percentage of them.
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