Hemostatic triggers of myocardial infarction

Plasminogen activator inhibitor 1 in acute coronary syndromes

Plasminogen activator inhibitor 1 (PAI-1) is the main regulator of endogenous fibrinolysis, overriding the impact of other constituents of fibrinolysis. In plasma, it can be found in three forms: active, latent and inactive. There are numerous commercially available tests, analysing the activity of PAI-1 or the antigen level, with variable correlations between the two. PAI-1 has been extensively studied regarding incidence and outcomes of acute coronary syndromes, and showed positive association with both in numerous studies. Higher PAI-1 has been associated with worse short- and long-term outcomes. Studies are more consistent in the primary percutaneous coronary intervention era. Higher rise of PAI-1 within the first 24 h of acute myocardial infarction has been linked to some of its high-risk features. The circadian pattern of PAI-1 kinetics has been previously described, and the mechanisms behind this phenomenon and its impact on the incidence of acute coronary syndromes are well known. Further investigations are needed to test the safety and efficacy of PAI-1 as a pharmacological target in cardiovascular diseases.

Temporal Patterns of Hospital Admissions for Transient Ischemic Attack: A Retrospective Population-based Study in the Emilia-Romagna Region of Italy

Acute cerebrovascular events are not randomly distributed over time but show specific temporal patterns of occurrence. However, most studies focused stroke and little is known about transient ischemic attack. This study aimed to explore the existence of a temporal pattern of transient ischemic attack and the possible influence by the most common risk factors. The analysis included all hospital admissions with the ICD9-CM code for TIA, recorded in the database of the Emilia Romagna region of Italy (1998-2006; n = 43642, mean age 76.8 ± 11.5 years, 45.5% males). Transient ischemic attack was most frequent in autumn and winter and less common in spring and summer (P < 0.0001), with the highest number of cases in October and the lowest in February, and also most frequent on Monday (P < 0.0001). This study shows a seasonal and weekly pattern in occurrence of transient ischemic attack, independent of sex and the presence of the most common risk factors.