Rapid detection of streptokinase resistance using a bedside lytic assay of dry reagent technology

A new bedside lytic assay using dry reagent technology for rapid (3-5 min) detection of streptokinase resistance (SKR) was recently introduced, which measures lysis onset time (LOT) of whole blood clot in response to high and low streptokinase (SK) concentrations: 100 U/ml (SK100) and 10 U/ml (SK10). SKR was defined by prolongation of LOT, previously correlated with the standard SK Reactivity Test and with clinical outcome of acute myocardial infarction (AMI) SK-treated patients, high SKR when SK100>50 seconds and SK10>120 seconds; partial SKR when SK10>120 seconds. Five prospective clinical groups (325 patients) were screened in cardiac units of four university hospitals, In patients previously treated with SK, the prevalence of SKR was 87% (70% high, 17% partial); in those who had documented streptococcal infection, 92% (75% high, 17% partial); and in patients with rheumatic heart disease, 76% (all high). SKR prevalence was 55% (33% high, 22% partial) in those with recent respiratory tract infection. In 225 acute coronary patients, SKR was 28% (21% high, 7% partial), and was identical by gender, but was 36% (32% high, 4% partial) in patients greater than or equal to 65 years Versus 19% (9% high, 10% partial) in those < 65 years (P < 0.0001). In conclusion, we demonstrated (with a rapid functional assay) the consistence of our results with the expected prevalence of SKR in the groups studied, this points out to the feasibility of pre-therapeutic detection of SKR and choice between t-PA and SK made at bedside without delaying the onset of treatment. As SKR is common among candidates for thrombolysis, pre-therapeutic detection of SKR merits further investigation. (C) 2000 Harcourt Publishers Ltd.