Atrial Fibrillation: An Underestimated Cause of Ischemic Monocular Visual Loss?

INTRODUCTION: Atrial fibrillation (AF) is a major cause of ischemic stroke and Transient Ischemic Attack (TIA) and investigation for paroxysmal AF is recommended following an embolic brain event. In contrast, retinal ischemic monocular blindness is traditionally considered most linked to carotid artery disease (CAS) and investigating for AF is less vigilant. We aimed to determine the prevalence of AF in patients with ischemic monocular blindness. METHODS: Consecutive records of all patients presenting to a daily TIA clinic with transient or permanent ischemic monocular blindness were reviewed, January 2014-October 2016. RESULTS: Of 400 patients, 224 (56.0%) were male, mean age 64.5 years (SD 15.1). A total of 263 (66%) presented with transient and 137 (34%) with permanent ischemic monocular blindness. ECG was performed in 364 patients (91%) but only 211 (52%) had further cardiac monitoring. The vast majority (97.3%) had carotid imaging. Thirty-six patients (9%) were found to have AF while 53 (14%) had ipsilateral CAS. Median ABCD2 score was 1 in AF and non-AF groups. Only 55% of known AF patients were anticoagulated at presentation, despite all having CHADVASC2 score greater than or equal to 1. Patients with AF had more hypertension (P = .004), previous TIA (P = .002), previous stroke (P = .044) and ischemic heart disease (P = .022) with no difference in age (P = .791), diabetes (P = .563), smoking (P = .460) nor hypercholesterolaemia (P = .083). CONCLUSIONS: A total of 9% of patients with ischemic monocular blindness had AF. This is an underestimate, as only 53% of patients had prolonged cardiac monitoring. Known AF was suboptimally managed with only 55% receiving anticoagulation despite being eligible.

Undertreatment of Vascular Risk Factors in Patients with Monocular Ischaemic Visual Loss.

BACKGROUND AND PURPOSE: Ischaemic visual loss is often considered a lower risk factor than other transient ischaemic attacks (TIA). We aimed to determine the recurrence risk, prevalence and management of vascular risk factors in these patients. METHODS: The study took place in the University College Hospital London daily TIA clinic, main referral centre for North-Central London and Moorfields Eye Hospital. Consecutive records for patients with transient (< 24 h) or permanent (> 24 h) ischaemic visual loss were reviewed during the period January 2014-October 2016. Patients diagnosed with temporal arteritis were excluded. RESULTS: Of 400 patients, 224 (56%) were male with mean age 64.5 years (SD 15.1); 263 patients (65.8%) presented with transient and 137 patients (34.2%) with permanent ischaemic visual loss; 51.3% had hypertension (HTN), 35.3% hypercholesterolaemia, 14.5% diabetes, 11.8% ischaemic ocular events, 10.0% ischaemic heart disease, 7.3% atrial fibrillation (AF), 6.3% TIA, 5.3% stroke, and 12.3% were smokers. Median vascular risk factors were 2 (range 1-6), but 122 (30.5%) had ≥3. Those with diabetes (p < 0.001), HTN (p = 0.008), previous myocardial infarction (p = 0.005), or ≥3 vascular risk factors (p = 0.012) were more likely to present with permanent visual loss, while patients with history of transient events, TIA (p = 0.002), or ocular (p = 0.002) presented with transient visual loss. Ninety-day recurrence was 10.5%; this was higher in patients with ≥3 risk factors (hazard ratio 1.42, 95% CI 0.95-2.11, p = 0.111). Patients with past TIA were more likely to be on secondary prevention than those with ocular ischaemia; 60.0 vs. 34.1% received antiplatelets and 76.0 vs. 43.9% statins. At presentation, only 55.2% (16 patients) with known AF were anticoagulated, despite all of them having CHADSVASC ≥1. CONCLUSIONS: Approximately one-third of patients with ocular ischaemia had ≥3 vascular risk factors with recurrences higher in these patients. Yet only half of those with previous ischaemic ocular events were on antiplatelets or statins. These patients should be investigated and treated as aggressively as other forms of TIA or stroke.