Early Recurrence of Cerebrovascular Events After Transient Ischaemic Attack
To the Editor:
We read with great interest the recent article by Lisabeth et al1 regarding the stroke risk after a transient ischemic attack (TIA). Their results are similar to those reported in the mid- and late-1990s2,3 and considerably lower than more recent studies reported in the UK4,5 and Canada.6 We run rapid access TIA clinics for the assessment and investigation of individuals referred by their general practitioner following a suspected cerebrovascular event that has not necessitated in-patient management. During a recent audit of this service we examined the rate of recurrent cerebrovascular events in new referrals over a 6-month period, to 2 hospitals in East Glasgow, Scotland. Information was obtained from the referral letter, clinic letters, health care practices, hospital records and investigating departments.
Of 372 new referrals to the clinics, 37 (10%) did not attend, 130 (35%) had a non-cerebrovascular diagnosis, and 205 (55%) were deemed to have suffered a probable or definite new TIA (121 [32.5%]) or minor stroke (84 [22.5%]). There were 19 documented recurrent cerebrovascular events in this group giving a crude recurrence rate of 9% (95% CI, 5 to 13%), of which 10 cases (5%; 95% CI, 2 to 8%) were known to have occurred within one week, and 15 (7%; 95% CI, 4 to 11%) within one month of the initial episode.
Of the patients who had an initial diagnosis of TIA there were 17 recurrent events (14%; 95% CI 8 to 20%), with 7 cases (6%; 95% CI 1 to 10%) occurring within one week, and 13 (11%; 95% CI 5 to 16%) within one month.
Multivariate analysis identified current cigarette smoking as the only independent risk factor for a recurrent event.
Our findings are more similar to those of Coull et al5 and Johnston et al6 and raise the concern that very early recurrence is a significant problem that will continue to grow in tandem with an ageing population. Although, it is presently unclear whether secondary preventative measures can reduce these early recurrent events, future research should be directed toward identifying the medical and organizational strategies that would best reduce the risk of such events.
Lisabeth LD, Ireland JK, Risser J, Brown DL, Smith MA, Garcia NM, Morgenstern LB. Stroke risk after transient ischaemic attack in a population-based setting. Stroke. 2004; 35: 1842–1846.
Hankey GJ. Impact of treatment of people with transient ischaemic attacks on stroke incidence and public health. Cerebrovasc Dis. 1996; 6 (Suppl 1): 26–33.
Wolf PA, Claggett GP, Easton JD, Goldstein LB, Gorelick PB, Kelly-Hayes M, et al. Preventing ischemic stroke in patients with prior stroke and transient ischaemic attack: a statement for healthcare professionals from the Stroke Council of the Am Heart Association. Stroke. 1999; 30: 1991–1994.
Coull AJ, Lovett JK, Rothwell PM. Population based study of early risk of stroke after transient ischaemic attack or minor stroke: implications for public education and organisation of services. BMJ. 2004; 328: 326.
We would like to thank Drs Whitehead, McManus, McAlpine, and Prof Langhorne for their interest in our paper. As their letter indicates, in our paper we found stroke risk after transient ischemic attack to be somewhat lower than recent studies on this topic. We feel it is critically important to examine findings from various studies using different methods and study populations to understand the risk of stroke after TIA. To this end, our findings provide estimates of risk from a prospective, population-based study of stroke and TIA in an ethnically diverse community using rigorous case ascertainment procedures to acquire all strokes and TIAs that present for medical attention.