Is a Carotid Doppler Scan Useful for Managing Patients with Suspected Ocular Ischemic Syndrome?

ABSTRACT

Purpose: This review aims to understand the value of a carotid Doppler scan (CDS) when managing patients with clinical/suspected ocular ischaemic syndrome (OIS); correlations between internal carotid artery (ICA) stenosis reports; subsequent patterns of referral to vascular experts; and subsequent decisions concerning surgical versus medical management. Methods: A retrospective review of 402 CDS requests by a single eye center over 4 years (2016-2019) for patients with a clinical suspicion of OIS was conducted. Data analysis included 344 patients who had reported CDS of both ICAs. We also studied referral patterns by ophthalmologists to other specialties. Results: CDS requests were related to the retina (53.2%), neuro/TIA problems (31.1%), glaucoma (10.5%) and other issues (5.2%). The majority of patients (209/344, 60.8%) had normal CDA results. Of the 688 ICAs reported, 469 (68.2%) were normal, 219 (31.8%) had atheroma present, and only 83 (12.1%) had significant stenosis. Of 83 ICAs with stenosis, 23 (27.7%) had ≥70% stenosis, 24 (28.9%) had 50-69% stenosis, and 25 (30.1%) had <50% stenosis. A total of 60/344 (17.4%) patients were referred to vascular/stroke teams 15/60 (25%) referred had bilateral disease, and only 2/60 (3.3%) were offered carotid endarterectomy. All referred patients commenced statins and low-dose aspirin. Conclusion: Our cohort showed a low incidence of ICA stenosis according to CDS reports in patients with suspected OIS. There were very low rates of vascular and endarterectomy referral. Commencement of conservative treatment (mini aspirin+statin) by ophthalmologists could be beneficial even in the early stage of presenting clinical evidence of OIS.

Ocular ischemic syndrome (OIS) covers a wide spectrum of eye problems resulting from reduced blood flow to the eyes. OIS is commonly known to be a rapidly blinding disease due to late diagnosis. A high index of suspicion can lead to early investigation and perhaps prevent blindness with timely intervention. The fluorescein angiogram is a reliable eye test to confirm OIS disease affecting the retina. If reduced retina perfusion is confirmed, a carotid Doppler artery scan (CDS) is the next investigation to detect blood vessel lumen narrowing primarily affecting carotid arteries (neck arteries). The presence of carotid artery disease can indicate risk of stroke; hence, confirmed carotid artery disease merits a referral to vascular surgeons to consider carotid artery surgery aiming to unblock the artery and improve blood flow and hopefully reverse OIS. Our study aimed to investigate the prevalence of suspected OIS patients referred for carotid Doppler scans, correlations between carotid artery stenosis results and clinical OIS, and subsequent offers of carotid artery surgery versus conservative medical management. Our study showed that carotid artery disease severity defined by CDS has a poor correlation with clinical diagnosis of OIS. Conservative treatment is advised for all patients with carotid artery disease, whereas surgical options for carotid stenosis are rarely offered. Hence, this study questions the benefit of pursuing CDS tests in OIS patients, since the results do not change their management. Finally, we highlight the need for better guidance on carotid artery stenosis referral for carotid surgery.