Recent advances in the management of transient ischemic attacks

Abstract

Significant advances in our understanding of transient ischemic attack (TIA) have taken place since it was first recognized as a major risk factor for stroke during the late 1950's. Recently, numerous studies have consistently shown that patients who have experienced a TIA constitute a heterogeneous population, with multiple causative factors as well as an average 5-10% risk of suffering a stroke during the 30 days that follow the index event. These two attributes have driven the most important changes in the management of TIA patients over the last decade, with particular attention paid to effective stroke risk stratification, efficient and comprehensive diagnostic assessment, and a sound therapeutic approach, destined to reduce the risk of subsequent ischemic stroke. This review is an outline of these changes, including a discussion of their advantages and disadvantages, and references to how new trends are likely to influence the future care of these patients.

Keywords: TIA; anticoagulants; antiplatelet therapy; arterial revascularization; stroke risk stratification; transient ischemic attack.

Figure 1.. Comparison of the anatomoclinical relationship between transient ischemic attack (TIA) and cerebral infarction with the acute coronary syndromes.

TIAs can be considered the equivalent of unstable angina, with symptoms lasting for a few minutes and then abating. They often have a longer duration and an imaging counterpart (positive diffusion weighted imaging [DWI]), which may be reversible. When the ischemic process is sufficiently severe, it results in permanent injury to the brain tissue. This "ischemic continuum" mirrors the findings in acute coronary syndromes, even to the point that cerebral infarctions resulting from large arterial occlusions are emergently managed endovascularly, just like an ST-elevation myocardial infarction (STEMI), while the smaller infarctions are handled by non-interventional means, just like a non-STEMI (NSTEMI).

Figure 2.. Variables that compose the different stroke risk scoring systems.

Three domains are used to group the components contained within the different stroke risk scoring systems. The earlier systems (i.e. California Risk Score [CRS], “age, blood pressure, clinical features, and duration of symptoms” [ABCD], and ABCD ²) only included components from the “risk factors” and “semiologic variables” domains. The more recent ones (i.e. ABCD ²-MRI, clinical imaging-based prediction [CIP], ABCD ²-I, ABCD ³-I, and ABCDE⊕), shown to have better predictability, added one or more components from the “imaging findings” domain.

Figure 3.. Optimal workflow in a transient ischemic attack (TIA) clinic.

A potential TIA patient is referred to the clinic and his visit with the vascular neurologist is expedited (lightning bolt). Upon assessment, if the patient is found not to have had a TIA, his care is diverted to an alternative clinical pathway. If the vascular neurologist determines that the patient has had a TIA, he can proceed by immediately requesting the appropriate diagnostic procedures. Test completion and results reporting are also expedited (lightning bolt), allowing the vascular neurologist to quickly review them and decide on a treatment strategy tailored to the patient's risk profile. Management includes patient and family education as well as appropriate referral to pre-specified specialists.