Forty-five eyes of 44 patients were identified from screening images as having new retinal emboli during the study period, all of whom had type 2 diabetes. Five patients were excluded from the study: four failed to attend the clinic, and one patient died of pneumonia during follow-up. Therefore, data from 39 patients were analyzed. A retinal embolus was present in the right eye in 25 patients and in the left eye in 14. Three patients had multiple emboli. Two patients had two emboli in one eye, and another patient had an embolus in both the left and right eyes. Further details of the cohort are given in Table 1.
During the course of the study, 13,643 individuals underwent retinal screening in the trust, which resulted in an incidence of retinal emboli in individuals with diabetes in Sunderland of 0.32% (32 in 10,000). At the initial clinic appointment, all patients were confirmed to be asymptomatic, although one patient experienced an episode of amaurosis fugax while under medical clinic review. During the study period, there were no separate referrals from the ophthalmology department as a result of detecting asymptomatic retinal emboli in diabetic patients.
Seventy-two percent (28/39) of the patients were men. Twenty-one percent (8/39) were current smokers, and 8% (3/39) were ex-smokers. Ischemic heart disease was present in 12/39 (31%), with 6/39 (12%) having previously undergone coronary artery bypass surgery. Twelve percent had a history of myocardial infarction, and 6/39 (12%) had suffered a stroke prior to the detection of the retinal embolus.
Eight patients (21%) were found to have significant carotid artery stenosis or complete occlusion on carotid Doppler ultrasound (Table 2). Doppler ultrasound was conducted at a mean of 13 days after the first appointment. Nine patients underwent carotid angiography after Doppler ultrasound to confirm the level of stenosis. Five of the nine angiograms were performed at the recommendation of the cardiovascular assessment team. The other four angiograms were performed to confirm complete occlusion in one carotid artery, and these patients were referred directly from the clinic. One angiogram identified more extensive stenosis than was found on the Doppler ultrasound. This patient had recurrent transient ischemic attacks (TIAs) after medical clinic review commenced, and was found to have 50–60% carotid artery stenosis on Doppler ultrasound. However, the angiogram subsequently showed occlusion of 80%, and the patient was then considered for carotid endarterectomy. Therefore, one patient was found to have significant carotid artery stenosis through angiography rather than Doppler ultrasound, meaning that nine patients (23%) overall were found to have significant carotid artery stenosis. All 44 patients received an echocardiogram, 43 of which were normal. One showed findings not considered relevant to embolic disease, but further cardiac investigations were carried out.
One patient underwent carotid endarterectomy (Table 2). This patient was initially found to have asymptomatic carotid stenosis and an asymptomatic retinal embolus. After surgical assessment, endarterectomy was discussed, but the patient declined intervention and was managed medically. Six months later, however, he experienced a retinal TIA, was re-referred, and underwent endarterectomy 9 days later.
The four patients considered for carotid stenting or carotid endarterectomy all had significant carotid artery stenosis without complete occlusion. One patient underwent carotid endarterectomy. Two patients declined surgery, and another was unable to lie flat to undergo angiography to further assess the extent of carotid artery stenosis. Therefore, these three patients received maximal medical therapy. The five patients with complete occlusion of one carotid artery also received maximal medical therapy (Table 2).
In total, 56% of the group had one or more changes made to medication (Table 2). The most common medication change was the addition of an antiplatelet agent, which occurred in 7/39 (18%) patients (Table 3). Twenty-one percent (8/39) received changes to lipid-lowering medication, 12/39 (31%) had changes to anti-hypertensive medication, and 6/39 (16%) had changes to diabetes medications (Table 3). Seven individuals underwent 24-h ambulatory blood pressure monitoring (24-h ABPM), with four patients receiving changes to anti-hypertensive medication as a result and three patients having normal 24-h ABPM.
We also examined the number of individuals with a history of stroke or TIA and the number of individuals who suffered strokes or TIAs after the detection of the retinal embolus. In total, ten patients (26%) experienced a cerebrovascular event either before or after detection of the retinal embolus. Four patients had a stroke or TIA between the time they were first seen and the time they were discharged from the clinic, and all were individuals who were found to have significant stenosis before having a stroke or TIA. The mean duration of clinic follow-up was 8 months. No patients suffered a stroke or TIA between discharge and case note review.