An Evaluation of the Activated Partial Thromboplastin Time Waveform

Abstract

The activated partial thromboplastin time (APTT) waveform includes several parameters that are related to various underlying diseases. The APTT waveform was examined in various diseases. Regarding the pattern of APTT waveform, a biphasic pattern of the first or second derivative curve (DC) was observed in patients with hemophilia and patients positive for antiphospholipid (aPL) antibodies or coagulation factor VIII (FVIII) inhibitors. The time of the first and second DC and fibrin formation at 1/2 height were prolonged in patients with hemophilia, patients with inhibitors, patients positive for aPL, patients treated with anti-Xa agents, and patients with disseminated intravascular coagulation (DIC). These values all tended to decrease in pregnant women (at 28-36 weeks' gestation). The height of the second derivative peak 1 was significantly lower in patients with hemophilia, patients with FVIII inhibitors, patients positive for aPL, patients treated with anti-Xa agents, and patients with DIC; these values tended to be significantly higher in pregnant women. The height of the first DC was significantly lower in patients who were positive for FVIII inhibitors and was significantly higher in patients treated with anti-Xa agents and pregnant women. The height of the first and second DC was useful for the analysis of hemophilia, FVIII inhibitor, and aPL.

Keywords: APTT; anticoagulant; biphasic waveform; hemophilia; waveform.

Figure 1.

Activated partial thromboplastin time (APTT) waveform. A, Normal volunteer. B, Patient with antiphospholipid antibody. C, Patient with hemophilia. D, Patient with inhibitor for factor VIII (FVIII). 1A, first derivative curve (DC); 1B, second DC; 1C, time for 1/2 height of fibrin formation; 2A, height of the second DC peak 1; 2B, height of the second DC peak 2; 2C, height of the first DC; 2D, height of fibrin formation; 3A, width of the second DC peak 1; 3B, width of the second DC peak 2; 3C, width of the first DC, bp, biphasic waveform.

Figure 2.

Second DC peak 1 (A), first DC peak (B), and time for 1/2 height of fibrin formation (C), second DC peak 1 height (D), Second DC peak 2 height (E), first DC peak height (F), and fibrin formation height (G). DC indicates derivative curve; Anti-Xa, patients treated with an anti-Xa agent; aPL(+), patients positive for antiphospholipid antibody; DIC, patients with disseminated intravascular coagulation; HA, hemophilia A; HB, hemophilia B; HVs, healthy volunteers; Inhibitor, patients positive for anti-FVIII antibody; PW, pregnant women; TP, thrombophilia; Warfarin, patients treated with warfarin.