Factor XIII A‐subunit concentration predicts outcome in stroke subjects and vascular outcome in healthy, middle‐aged men

There is growing evidence for a role of factor XIII (FXIII) in vascular disease. FXIII measures were determined in (i) a nested case–control study from the Second Northwick Park Heart Study of 63 men with myocardial infarction (MI) and 124 age‐matched controls and (ii) in a case–control study of 475 subjects with acute stroke and 461 controls followed up for 54 months for mortality. In both studies, measures of FXIII A‐ and B‐subunit antigen, FXIII activity and prothrombin fragments (F1 + 2) were made. An in vitro model was used to investigate the effects of thrombin activity on FXIII A‐ and B‐subunit antigen levels. In study 1, patients clinically free of coronary artery disease who later developed MI had lower adjusted FXIII A‐subunit levels at recruitment (129·2%vs 113·3%, P = 0·007). In study 2, stroke patients with large vessel disease had lower A‐subunit antigen levels (102·1%vs 127·2%, P