Atherosclerosis is a chronic andsystemic inflammatory disease that develops slowly and is reflected by the presence of atherosclerosis plaques in several arterial beds.It is considered the leading cause of cardiovascular disease worldwide. Plaque rupture is the major cause of ischemic stroke or myocardial infarction and can be predicted by atherosclerotic plaque instability. Intraplaque hemorrhage (IPH) is the main factor of plaque instability and is promoted by an hypoxic and pro-inflammatory environment. Obstructive sleep apnea syndrome (OSAS) is strongly associated with cardiovascular diseases and is known to promote early stages of atherosclerosis. OSAS is associated with higher stroke risk. However, it is still largely underdiagnosed in patient with carotid atherosclerotic plaque and its potential role in plaque instability is unknown.

The objective of the present study is to evaluate the prevalence of OSAS in patients with atheroma carotid plaque and to evaluate whether OSAS may promote IPH.

In this study, OSAS’ risk is determined with STOP BANG (SB) questionnaire in 147 patients who underwent carotid endarterectomy. All patients with a SB score >2 were proposed a polysomnography (PSG). Then, carotid plaques were embedded in paraffin and sections stained with Perl's Blue to evaluate IPH. A score was defined (from 0=no IPH to 3=large IPH).

Only 12.8% of our population had a sleep test prior to their appointment at the vascular medicine service. However, the SB results show that 89% of our population have at least a moderate risk of OSAS and a PSG should be performed. So far, 13 patients agreed to perform a PSG. Among them, 11 were diagnosed with OSAS requiring treatment. Interestingly, the IPH score measured by Perl's Blue in carotid biopsies is higher in-patient wither higher risk of OSAS (SB>3) than in low-risk patient (SB≤3) (1.78 vs 1.05, P=0.04).

In conclusion, we demonstrated that OSAS is largely underdiagnosed in our population even if we highlighted a potential role of OSAS in IPH development. Further experiments are ongoing to assess the real prevalence of OSAS by increasing the number of patients doing PSG in our population and to confirm the link between OSAS and IPH.