This transient ischemic attack (TIA) prognosis calculator for stroke risk predicts the occurrence of stroke based on five independent risk factors. There is more information on this prediction index and its usage below the form.
How does the transient ischemic attack (TIA) prognosis calculator for stroke risk work?
This health tool determines the short term risk of stroke (90 days after TIA) and other adverse events (such as recurrent TIA, admission for cardiovascular conditions or death) for the patient who was just diagnosed with transient ischemic attack.
It is based on a cohort study on 1707 patients with a mean age of 72 years and most subjects presenting risk factors for hypertension and diabetes as well.
The study also concluded there are five independent factors associated with stroke risk in patients with TIA which are presented in the following table:
| Risk factors | Odds ratio | 95% CI | P |
| Age >60 years | 1.8 | 1.1-2.7 | =.01 |
| Diabetes mellitus | 2 | 1.4-2.9 | <.001 |
| TIA duration >10 min | 2.3 | 1.3-4.2 | =.005 |
| Weakness during TIA | 1.9 | 1.4-2.6 | <.001 |
| Speech impairment | 1.5 | 1.1-2.1 | =.01 |
The table below presents the risk percentages in the possible cases of the five risk factors being present:
| Number of present risk factors | Risk of stroke and/or adverse events |
| 0 | No risk |
| 1 | 3% |
| 2 | 7% |
| 3 | 11% |
| 4 | 15% |
| 5 | 34% |
In 2008, another score accounting for stroke risk factors was published, the ABCD2. Both scores have been validated in different studies and the results have shown that both perform similarly in terms of stroke prognosis with the ABCD2 being deemed slightly more predictive.
Other risk indices are still trying to establish the one year or more, long term risk of stroke after TIA.
One limitation of the above TIA index and other prediction tools is the fact that they address to patient over 60 and don’t offer prediction in the case of younger patients (for instance, those with non-atherosclerotic TIA, or posterior circulation TIA).
TIA prognosis and predicting ischemic stroke
The implementation of a generally accepted method to assess and define short term prognosis and subsequent risk of stroke in the case of patients with TIA is important for the standardization of patient management (which at the moment varies between admission and outpatient treatment, depending on institution).
TIA is the medical term for a cohort of neurological symptoms (such as numbness) that are rapid in occurrence and succession and which are caused by a temporary disruption of blood flow in an area of the brain.
The correct and rapid diagnosis of TIA is essential because these events are often succeeded by an ischemic stroke.
TIA symptoms are similar to that of stroke, including:
■ Weakness;
■ Unilateral or bilateral numbness in limbs;
■ Visual or speech impairment;
■ Facial drop on one side.
The duration of the symptoms can be as little as a few minutes or as much as a few hours but most TIAs resolve within 24 hours.
The most common risk factors include hypertension, obesity, high cholesterol, alcoholism, atrial fibrillation or diabetes.
Because most symptoms resolve within minutes or hours, treatment for a transient ischemic attack addresses the risk of stroke and tries to eliminate the underlying cause of the ischemic episode.
Stroke risk is highest within days of TIA and often, brain and vessel imaging improves prediction and subsequently prevention management.
References
1) Johnston SC, Gress DR, Browner WS, Sidney S. (2000) Short-term prognosis after emergency department diagnosis of TIA. JAMA; 284(22):2901-6.
2) Lemmens R, Smet S, Thijs VN. (2013) Clinical Scores for Predicting Recurrence After Transient Ischemic Attack or Stroke: How Good are They? Stroke; 44:1198-1203.
3) Kernana WK. (2007) Stroke after transient ischaemic attack: dealing in futures. Lancet; 369:251-252.
29 Aug, 2016