We utilized a kaolin-activated partial thromboplastin time (APTT) using rabbit brain phospholipid, in which the capacity of a fourfold increased “high” phospholipid concentration (PC) to normalize the abnormal “standard” PC-APTT in patients with lupus anticoagulants is assessed. This system was also used to measure factors VIIIC, IX, and XI. The tissue thromboplastin inhibition test (TTI), a prothrombin time system in which the activity of a lupus anticoagulant is unmasked by the use of dilute thromboplastin, was simultaneously evaluated. Test sensitivity was defined by results on 31 consecutive patients with standard PC-APTT inhibitors and no bleeding tendency. Specificity was based on 94 patients with various other coagulopathies, including coagulation factor inhibitors, severe congenital factor deficiencies, hepatic insufficiency, and warfarin and heparin treatment. Twenty-one patients with lupus erythematosus and standard PC-APTT results within normal limits were also tested. Sensitivity of the APTT system was superior to that of the TTI (97% v 58%); high PC normalized clotting time ratios and factor levels. Positive results were common with both assays in the group of 20 heparinized patients. The APTT system had superior specificity in remaining cases; there were no positive tests among 74 patients. The lupus erythematosus group had a significant decrease in the clotting time ratio with high PC, indicating that low- level lupus anticoagulants are quite prevalent in this group. The kaolin clotting time using rabbit brain phospholipid in standard and high concentrations is a simple, sensitive, and specific technique for diagnosis of lupus anticoagulants.

Lupus anticoagulants and/or anticardiolipin antibodies were detected in 100 patients with autoimmune disorders, thrombosis, or pregnancy loss. Significant agreement between tests for these two antiphospholipid activities was lacking. Performing both assays is thus important in maximizing the likelihood of detecting antiphospholipids that may have clinical relevance.

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Hemostasis is often abnormal in adults with con genital heart disease, and von Willebrand factor abnormalities have been reported in this patient population. We sought to determine the prevalence, type, and severity of the von Wil lebrand factor abnormality, and its relationship to three patho physiological variables; cyanosis, pulmonary vascular disease, and turbulent blood flow. This prospective study comprised 76 unoperated congenital heart disease patients aged 20 to 68 years (mean = 34 years). There were 44 cyanotic and 32 acyanotic patients. Twenty-seven cyanotic and 6 acyanotic pa tients had pulmonary vascular disease, 31 cyanotic and 16 acyanotic patients had turbulent blood flow, and 11 patients were acyanotic without pulmonary vascular disease or turbu lent flow. The largest plasma von Willebrand factor multimers were relatively decreased or absent in 77% of cyanotic versus 41 % of acyanotic patients ( p < .001); in 76% of patients with, versus 51 % without, pulmonary vascular disease ( p < .029); and in 72% of patients with, versus 45% without, turbulent flow ( p <.016). Von Willebrand factor multimers were normal in all 11 acyanotic patients without pulmonary vascular disease or turbulent blood flow. Von Willebrand factor multimer ab normalities normalized after reparative surgery in five patients. Depletion of the largest plasma von Willebrand factor multim ers is common in adults with congenital heart disease. Cyano sis, pulmonary vascular disease, and turbulent flow are deter minants of the abnormality that is acquired and reversible.