A modified in vitro clot lysis assay predicts outcomes and safety in acute ischemic stroke patients undergoing intravenous thrombolysis

Abstract

The outcome of intravenous thrombolysis using recombinant tissue plasminogen activator (rt-PA) is only favorable in ≈ 40% of acute ischemic stroke (AIS) patients. Moreover, in ≈ 6-8% of cases, intracerebral hemorrhage (ICH) develops. We tested whether a modification of clot lysis assay (CLA), might predict therapy outcomes and safety. In this prospective observational study, blood samples of 231 AIS patients, all receiving intravenous rt-PA, were taken before thrombolysis. Cell-free DNA (cfDNA), CLA and CLA supplemented with cfDNA and histones (mCLA) were determined from the blood samples. Stroke severity was determined by NIHSS on admission. ICH was classified according to ECASSII. Short- and long-term outcomes were defined at 7 and 90 days post-event according to ΔNIHSS and by the modified Rankin Scale, respectively. Stroke severity demonstrated a step-wise positive association with cfDNA levels, while a negative association was found with the time to reach 50% lysis (50%CLT) parameter of CLA and mCLA. ROC analysis showed improved diagnostic performance of the mCLA. Logistic regression analysis proved that 50%CLT is a predictor of short-term therapy failure, while the AUC parameter predicts ICH occurrence. A modified CLA, supplemented with cfDNA and histones, might be a promising tool to predict short-term AIS outcomes and post-lysis ICH.

Figure 1

Association between cell free DNA (cfDNA) levels on admission and the severity and outcomes of stroke. Association between cfDNA levels on admission and stroke severity (A), short term outcome of stroke (B), long-term outcome of stroke (C), and therapy-associated intracerebral hemorrhage (D). cfDNA, cell free DNA; ICH, intracerebral hemorrhage; NIHSS, National Institutes of Health Stroke Scale, mRS, modified Rankin Scale, **p < 0.01, *p < 0.05 [(A) Kruskal–Wallis with Dunn-Bonferroni post hoc test, (B–D) Mann–Whitney U test].

Figure 2

Association between 50% clot lysis time (50%CLT) parameter of the clot lysis assay (CLA) or modified clot lysis assay (mCLA) and the severity and outcomes of stroke. Association between the 50%CLT parameter of CLA and stroke severity (A), short term outcome of stroke (C), long-term outcome of stroke (E), and therapy-associated intracerebral hemorrhage (G). Association between the 50%CLT parameter of mCLA and stroke severity (B), short term outcome of stroke (D), long-term outcome of stroke (F), and therapy-associated intracerebral hemorrhage (H). CLA, clot lysis assay; mCLA, modified clot lysis assay including the effect of cfDNA and histones; 50% CLT, 50% clot lysis time, ICH, intracerebral hemorrhage; NIHSS, National Institutes of Health Stroke Scale, mRS, modified Rankin Scale. *p < 0.05, **p < 0.01, ***p < 0.001 [(A,B) Kruskal–Wallis with Dunn-Bonferroni post hoc test, (C–H) Mann–Whitney U test].