Transient Ischemic Attacks Preceding Ischemic Stroke and the Possible Preconditioning of the Human Brain: A Systematic Review and Meta-Analysis

Abstract

Stroke is a leading cause of mortality and disability worldwide. Transient ischemic attack (TIA) is defined as transient brain ischemia with temporary neurological deficits. In animal models, prior TIA seems to enhance brain ischemic tolerance to withstand further ischemic events, which might be explained by brain preconditioning. Thus, this review aims to formulate evidence of whether TIAs can induce positive preconditioning and enhance the functional outcomes in patients suffering from subsequent ischemic strokes. Five databases were searched (PubMed, Embase, SAGE, Web of Science, and Scopus), and twelve studies were included in the quantitative analysis. Studies were eligible when comparing patients with acute ischemic stroke (AIS) and previous TIA with those with AIS without TIA. Comparisons included the National Institute of Health Stroke Scale (NIHSS) score at admission and 7 days from the stroke event, modified Rankin score (mRS), and Trial of ORG 10,172 in Acute Stroke Treatment (TOAST) classification. Odds ratio (OR), mean difference (MD), and 95% confidence interval (CI) were used to describe our results using the random effect model. Our results revealed that patients with stroke and prior TIAs had lower NIHSS scores at admission than those without prior TIAs. However, the NIHSS score was not significantly different between the two groups at 7 days. Furthermore, there was no statistically significant difference between both groups in terms of mortality. Despite the differences in the admission mRS score groups, patients with prior TIAs had lower mRS scores at discharge.

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

“…TIA is a common ischemic cerebrovascular disease, consistent with endogenous local ischemic preconditioning. Evidence has shown that stroke patients with prior TIA have a better prognosis than those without TIA, indicating that TIA induces ischemic tolerance [ 26 , [36] , [37] , [38] , [39] ]. It was supported by a systematic review and meta-analysis, revealing that patients with prior TIA had lower NIHSS scores at admission and lower scores on discharge [ 39 ].…”

Acute ischemic stroke prediction and predictive factors analysis using hematological indicators in elderly hypertensives post-transient ischemic attack

“…Innovatively, we predicted the occurrence of AIS within three years in a patient cohort defined by three stratifying factors: elderly age, transient ischemic attack (TIA), and hypertension. Each of these is a key factor for AIS incidence 4 , 9 , 44 , and older hypertensive patients with TIA are undoubtedly a high-risk group in need of predictive assessment for AIS. We opted for the simplest model comprising only seven PDHIs ('SIRI', 'HCT', 'RDW_CV', 'PLT', 'BAS_p', 'IG_p', and 'EOS'), given its comparable performance to more complex models.…”

Prevalence and In-hospital outcomes of diabetes among acute ischemic stroke patients in china: results from the Chinese Stroke Center Alliance

“…Previous studies showed that the presence of a prior TIA was associated with a favorable outcome in ischemic stroke patients, suggesting a neuroprotective effect of TIA possibly by inducing a phenomenon of ischemic tolerance allowing better recovery from a subsequent ischemic stroke [ 28 , 29 ]. However, some studies failed to confirm this [ 30 ]. The discrepancy of results may result from the difference in the type of stroke, inconsistent definition of study endpoint, and bias in the record of previous TIA.…”