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

Abstract

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 pro longation 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 streptoco ccal 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% h igh, 7% partial), and was identical by gender, but was 36% (32% high, 4% partial) in patients ≥ 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.