Transient monocular blindness and the risk of vascular complications according to subtype: a prospective cohort study
J Neurol
Transient monocular blindness and the risk of vascular complications according to subtype: a prospective cohort study
Eline J. Volkers 0 1 2 3
Richard C. J. M. Donders 0 1 2 3
Peter J. Koudstaal 0 1 2 3
Jan van Gijn 0 1 2 3
Ale Algra 0 1 2 3
L. Jaap Kappelle 0 1 2 3
0 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht , Utrecht , The Netherlands
1 University Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht , Utrecht , The Netherlands
2 Department of Neurology, Erasmus Medical Center , Rotterdam , The Netherlands
3 Department of Neurology , Diakonessenhuis, Utrecht , The Netherlands
Patients with transient monocular blindness (TMB) can present with many different symptoms, and diagnosis is usually based on the history alone. In this study, we assessed the risk of vascular complications according to different characteristics of TMB. We prospectively studied 341 consecutive patients with TMB. All patients were interviewed by a single investigator with a standardized questionnaire; reported symptoms were classified into predefined categories. We performed Cox regression analyses with adjustment for baseline vascular risk factors. During a mean follow-up of 4.0 years, the primary outcome event of vascular death, stroke, myocardial infarction, or retinal infarction occurred in 60 patients (annual incidence 4.4 %, 95 % confidence interval (CI) 3.4-5.7). An ipsilateral ischemic stroke occurred in 14 patients; an ipsilateral retinal infarct in six. Characteristics of TMB independently associated with subsequent vascular events were: involvement of only the peripheral part of the visual field (hazard ratio (HR) 6.5, 95 % CI 3.0-14.1), constricting onset of loss of vision (HR 3.5, 95 % CI 1.0-12.1), downward onset of loss of vision (HR 1.9, 95 % CI 1.0-3.5), upward resolution of loss of vision (HR 2.0, 95 % CI 1.0-4.0), and the occurrence of more than three attacks (HR 1.7, 95 % CI 1.0-2.9). We could not identify characteristics of TMB that predicted a low risk of vascular complications. In conclusion, careful recording the features of the attack in patients with TMB can provide important information about the risk of future vascular events.
Amaurosis fugax; History symptoms; Transient ischemic attack; Etiology
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Transient monocular blindness (TMB) or amaurosis fugax
[1] is usually attributed to temporary ischemia of the retina,
or part of it. Therefore, these episodes are considered
transient ischemic attacks (TIAs) in the territory of the
ipsilateral internal carotid artery (ICA) [2]. In general,
patients with TMB associated with atheromatous disease in
the carotid artery have an average 1 year risk of recurrent
stroke of 2 % [3, 4], but in patients with severe ICA
stenosis the risk of ipsilateral stroke is up to 16 % after
3 years [5]. Overall, the risk is two to three times lower
than in patients with cerebral TIA [5, 6].
The diagnosis of TMB may be difficult, because the
history is the only source of information while the range of
visual symptoms is almost unlimited [7, 8]. Consequently,
management can be difficult as well; because it is unknown
which patterns are most relevant with respect to future
vascular complications. Therefore, it is often challenging to
distinguish between TMB with a high risk versus low risk.
Earlier research on the predictive value of history
characteristics of TMB focused on the relationship between
visual symptoms and presence of ipsilateral carotid
atherosclerotic disease or other sources of emboli [8–10].
For the current study, we hypothesized that specific
patterns of transient monocular loss of vision may carry a
different prognosis, which might guide clinicians in
differentiating between serious and more benign causes of
TMB.
Between September 1992 and March 1996, we
prospectively included 341 consecutive patients from 18 centers.
Patients were required to have experienced sudden,
transient loss of vision in one eye in the previous 6 months; the
attacks did not last longer than 24 h and were not caused by
known ophthalmological disease.
This study was approved by the central research ethics
committee of the University Medical Center Utrecht, The
Netherlands; all patients gave written informed consent to
participate.
History characteristics
All patients were interviewed about the details of the attack
by one and the same investigator (RCJMD). The median
interval between the last attack and the interview was
8 weeks. This detailed history was guided by a
standardized questionnaire (Supplementary Table 1). If the patient
did not spontaneously mention a characteristic of a given
category, the possibilities in that category were read out by
the investigator, after which the patient could answer ‘yes’,
‘no’, or ‘I do not know’. If a symptom not listed in
Supplementary Table 1 was mentioned by the patient, the
characteristic was recorded in the patient’s own words;
afterwards t (...truncated)