Shortened activated partial thromboplastin time, a hemostatic marker for hypercoagulable state during acute coronary event

Various factors may contribute to a hypercoagulable state and acute vascular thrombosis. A prospective study was conducted involving 165 coronary heart disease (CHD) patients from the Cardiology Unit, Hospital Universiti Sains Malaysia. The purpose of this study was to investigate the relationship among factor VIII (FVIII), prothrombin time (PT), activated partial thromboplastin time (APTT), and activated protein C resistance (APC-R) state among CHD patients and to look for potential clinical applications from these laboratory findings. There were 110 cases diagnosed as acute coronary syndrome (ACS), whereas another 55 were stable coronary artery disease (SCAD) patients. PT, APTT, FVIII, and APC-R assays were performed on all subjects. There was a significant difference between the FVIII level and the APTT results (P value < 0.0001). A negative relationship was found between the FVIII level and the APTT from linear regression analysis (R² = 10%, P value < 0.0001). For each 1% increase in the FVIII level, the APTT was reduced by 0.013 s (95% confidence interval (CI) between –0.019 and –0.007). Interestingly, none of the SCAD patients had abnormally short APTT. Approximately 68.4% of cases with a positive APC-R assay were found to have a high FVIII level. In conclusion, the APTT test is a potential hemostatic marker for hypercoagulable state including in arterial thrombosis.

Abbreviations: ACS, acute coronary syndrome, APC-R, activated protein C resistance, APTT, activated partial thromboplastin time, CHD, coronary heart disease, CI, confidence interval, FV, factor V, FVIII, factor VIII, HUSM, Hospital Universisti Sains Malaysia, PPP, platelet poor plasma, PT, prothrombin time, SCAD, stable coronary artery disease