Verlauf von zirkulierendem Fibrinogen beim akuten Myokardinfarkt unter thrombolytischer Therapie mit rt-PA

Abstract

In 12 patients treated with WO mg rt-PA 3 h for acute myocardial infarction (AMI), serial fibrinogen levels were measured with the Clauss clotting rate assay ("functional 62Lab.med. 18: 62 (1994) Brought to you by | University of Queensland -UQ Library Authenticated Download Date | 6/18/15 8:57 PM Originalie J fibrinogen ") andwith a newenzyme immunoassay for immunologically intact fibrinogen ("intact fibrinogen "). Levels off u national and intact fibrinogen were strikingly different: fuYictional levels were higher at baseline; showed a more pronounced breakdown during rt-PA therapy; and a rebound phenomenon which was not seen for intact fibrinogen. The rat/o offunctionalto intactfibrinogen wascalculatedforeach individual patient and each time point. The mean ratio (n = 12) was 1.6 at baseline, 1.0 at 90 min., and increased markedly between 8 and 24htoa maximum of2.1 (p < 0.01), indicating thatfunctionalityofcirculating fibrinogen changes during AMI and subsequent thrombolytic therapy. The increased ratio offunctional to intact fibrinogen seems to reflect a more functional fibrinogen at baseline and following rt-PA infusion. This is in keeping with data that the relative amount of fast clotting intact HMW fibrinogen of total fibrinogen is increased in initial phase ofAMI. The data suggestthatabout20 % ofHMW fibrinogen are converted to partly degraded fibrinogen during rt-PA infusion. The rebound phenomenon exhibited by functional fibrinogen may result from newly synthesized fibrinogen with a high proportion of HMW fibrinogen with itsknown higher degree of phosphorylation. Fibrinogen-and fibrin degradation products were with i n normal ränge atbaseline. Upon infusion ofthe thrombolytic agent, maximum median levels of 5.88 \ig/ml and 5.28 [ig/ml, respectively, were measured at 90 minutes. Maximum plasma fibrinogen degradation products represented only 4% oflost intact fibrinogen, buttheycorrelatedstrongly and linearly with the extent of intact fibrinogen degradation (r=0.82, p<0.01). In contrast, no correlation was seen between breakdown of intact fibrinogen and corresponding levels of fibrin degradation products. We conclude from our data that the ratio offunctional to immunologically intact fibrinogen may serve äs an important Index for functionality of fibrinogen and select patients at high risk for early reocclusion. Only a small proportion of degraded functional and intactfibrinogen, respectively, is recoveredas fibrinogen degradation products. There seems to be a strong correlation between the degree of elevation of fibrinogen degradation products and the intensity of the Systemic lytic state, i.e. fibrinogen degradation.Keywords: fibrinogen and fibrin degradation products-enzyme immunoassay-intact fibrinogen -functional fibrinogen -acute myocardial infarction -rt-PA therapy

Associations of plasma fibrinogen assays, C-reactive protein and interleukin-6 with previous myocardial infarction

“…Other routine fibrinogen assays include the prothrombin time‐derived assay (PTF) [14]; and the immunonephelometric assay [15]. When the ratio of values found with the von Clauss assay and those obtained using a recently developed ELISA for the total of high molecular weight (HMW) and low molecular weight (LMW) fibrinogen (intact fibrinogen, ITF) was calculated, normal donors had a ratio close to 1, whereas patients with acute MI had a mean ratio of 1.6 before thrombolytic therapy, rising to 2.1 at 24–72 h after therapy [16–19]. It was suggested that this increased ratio represents ‘hyperfunctional’ fibrinogen (i.e.…”