Comparative behaviour of the components of the factor VIII complex in acute myocardial infarction.

ABSTRACT

The three components of the factor VIII complex VIII coagulant (VIIIC), VIII related antigen (VIII RAg) and the VIII related von Willebrand factor (VIII RWF) were studied in patients with acute myocardial infarction (AMI). Using a carefully standardized technique for the determination of VIII RWF, a significantly higher RWF level was found in 32 patients compared to 19 control subjects, confirming our previous results. However VIII RAG was increased to an even greater extent, resulting in a VIII RAg/VIII RWF ratio of 1.58 +/- 0.084 in patients, compared to 1.21 +/- 0.045 in controls. A similar increase of the VIII RAG/VIIIC ratio was noted in the 13 patients in whom VIIIC was investigated. In 7 patients with severe AMI who could be investigated twice the plasma levels of both VIII RAg and VIII RWF were found to be lower a week after the acute event than during the first 48 hours. However the VIII RAg/VIII RWF ratio was not significantly reduced after 7 days. Acute phase reaction and endothelial injury resulting in release of multimers which are less polymerised are probably involved in the above changes.