Definition and Evaluation of Transient Ischemic Attack: A Scientific Statement for Healthcare Professionals From the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on
Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease: The American Academy of Neurology affirms the value of this
statement as an educational tool for neurologists.
Abstract
This scientific statement is intended for use by physicians and allied health personnel caring for patients with transient ischemic attacks. Formal evidence review included a structured literature search of Medline from 1990 to June 2007 and data synthesis employing evidence tables, meta-analyses, and pooled analysis of individual patient-level data. The review supported endorsement of the following, tissue-based definition of transient ischemic attack (TIA): a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction. Patients with TIAs are at high risk of early stroke, and their risk may be stratified by clinical scale, vessel imaging, and diffusion magnetic resonance imaging. Diagnostic recommendations include: TIA patients should undergo neuroimaging evaluation within 24 hours of symptom onset, preferably with magnetic resonance imaging, including diffusion sequences; noninvasive imaging of the cervical vessels should be performed and noninvasive imaging of intracranial vessels is reasonable;
electrocardiography should occur as soon as possible after TIA and prolonged cardiac monitoring and echocardiography are reasonable in patients in whom the vascular etiology is not yet identified; routine blood tests are reasonable; and it is reasonable to hospitalize patients with TIA if they present within 72
hours and have an ABCD² score ≥ 3, indicating high risk of early recurrence, or the evaluation cannot be rapidly completed on an outpatient basis. (Stroke. 2009;40:2276-2293.)
J. Donald Easton, Jeffrey L. Saver, Gregory W. Albers, Mark J. Alberts, Seemant Chaturvedi, Edward Feldmann, Thomas S. Hatsukami, Randall T. Higashida, S.
Claiborne Johnston, Chelsea S. Kidwell, Helmi L. Lutsep, Elaine Miller and Ralph L. Sacco
Stroke 2009;40;2276-2293; originally published online May 7, 2009; DOI: 10.1161/STROKEAHA.108.192218
Comment by Bo Norrving
The group of American experts led by Dr. J.D. Easton gave us an extremely important statement about modern approaches toward TIA. Until now many practicing neurologists and other physicians are regarding TIA as a mild event not requiring urgent attention, and can be sent from emergency room to be evaluated by the general practitioner or as an outpatient. Presently diagnosis and management of TIA is undergoing a similar process like stroke 20 years ago. Nobody is now thinking that stroke can be not admitted to hospital, and diagnosed and treated immediately in a stroke unit. In the last ten years many data accumulated supporting the view that TIA is an emergency, must be diagnosed and treated at once, and that such an approach reduces the risk of stroke even by 80%. Careful and deep analysis of recent studies on TIA is given in the paper, as well as practical indications are provided.
We can learn which diagnostic methods should be applied immediately and which later. The authors emphasize the value of ABCD2 scoring scale ( Age, Blood pressure, Clinical signs, Duration and Diabetes), which helps us make a decision which case really needs immediate evaluation and management in hospital due to a high risk of stroke in n next few days and which can be diagnosed in short delay. The scale is very simple, easy to understand and everybody should learn it.
The discussion about the new definition of TIA is also important. In daily practice we are still using a traditional definition based on time, in which we classify patients as having TIA if the signs typical for stroke resolve within 24 hours. In the pre imaging era it was assumed that in such cases there is only transient ischemia which does not leave any permanent pathological changes. Due to common use of MR/CT we now that in up to 30% in such cases we can see new ischemic lesions. The new definition in of TIA is proposing that despite complete resolution of clinical signs, if on MRI (best with DWI option)or CT we can see vascular lesion, such case should be classified as stroke. This definition forces us to make imaging diagnosis immediately. This definition is in concordance with cardiologists who divide cardiac ischemia as STEMI (analog to stroke) and NSTEMI (analog to TIA). Cardiologists diagnose and treat both these heart ischemia states immediately. Everybody who is not yet convinced to the new definition will find pros and cons in this paper.
However applying the new definition and new diagnostic procedures to all TIA cases is not so simple in many places. Although neuroimaging machines are more and more widely available, access is not completely free. Physicians working in emergency rooms and in outpatient clinics have to learn more about TIA. We also have to educate the public, that even transient signs cannot be ignored.
Having in hand such well done paper it will be much easier to cross barriers and to force new approach to TIA.
Bo Norrving, MD, Prof
former Chair of the EFNS Scientist Panel on Stroke
Lund University Hospital, Norway
Comment by Gian Luigi Lenzi
The paper from Easton et al (Stroke; 2009; 40; 2276-2293) was selected for the “opening” of NEUROPENEWS, out of all the neurological papers published in the solar year 2009, on the criterion that it has received the largest number of quotations after its publication until June 2011, that is in no less than 18 months, for the topic “stroke”. This criterion presents a con and a pro. The con is that papers are presented in the TOP12 Section when they are any more breaking news stuff. The pro is that they are selected by the neurological world, and not by single editors or experts or fans.
In re-reading the paper from Easton et al, on the definition and evaluation of a TIA, I had a post-hoc feeling and a more general comment. The feeling derives from the steps that cerebrovascular research has made since the publication of this paper on the “new” definition of a TIA. And the feeling is, broadly speaking, a negative one. TIA Clinics have opened in some University Hospitals, but at a difficult cost-to-benefit equilibrium. In the UK, TIAs are certainly considered today an important medical urgency, but the entire UK phylosophy towards stroke has changed in the 8 years interval between XIth and the XII Editions of the Brain’s Diseases of the Nervous System Textbook. The sentence “Of course, many stroke patients and most transient ishemicattack patients are not admitted to hospital or even seen as outpatients…” has vanished in the 2009 Edition.
In my opinion, the utilization of undetermined definitions, such as “…transient…” and “…without evidence of clinical infarction” represents a compromise between the western world hypertechnological approach and what is happening in the other 4/5 of the Earth. In practical terms, do patients with a TIA (with symptoms that recover in 90% of them within 90 minutes) have to be admitted to a STROKE UNIT? Is the answer YES-NO linked to the ABCD2 score? Not all vascular neurologists around the world seem to have a total faith in the ABCD-xyz Score (cfr Purroy et al; Cerebrovasc Dis, 2012; 33; 182-189).
I would have preferred a plain statement such as “TIA is a stroke, that is the clinical presentation of a TIA and the clinical presentation of a STROKE are in the largest majority of cases both due to the same pathology, focal cerebral ischemia.” And I would have preferred a time limit of 90 minutes for the definition of a clinical event as a TIA.
My more general comment is due to the striking continuity over decades of the 24 hour time interval for the definition of a TIA (however in the Easton paper this interval is maintained for the neuroimaging evaluation only). I bet that the largest majority of neurologists think that this time interval was determined on the basis of important experimental data. The facts that brought to the 24 hours decision are different: this 24h interval was temporarily fixed by Prof Millikan in a Princeton Conference in the late 50ies ( or early 60ies) only because….. it was late and dinner was ready and the wives were unhappy to wait longer! “So, my friends”, said the Chairman Millikan to the audience, “our wives are waiting for us and dinner will get cold. Let’s agree for now on 24 hours, and tomorrow morning we will reconvene and we continue our discussion.” They did not reconvene after breakfast, and the 24 hour time interval for the recovery of symptoms in a TIA lasted … from that dinner to now.
Gian Luigi Lenzi is Professor of Neurology at the Sapienza University of Rome, Italy, Vice-President of the EFNS and Co-Editor in Chief of Neuropenews
