Prognostic implication of activated partial thromboplastin time after reteplase or half-dose reteplase plus abciximab: results from the GUSTO-V trial

AIMS

To evaluate the relationship between activated partial thromboplastin time (aPTT) and clinical outcomes in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-V) trial comparing standard-dose reteplase to half-dose reteplase and abciximab.

METHODS AND RESULTS

We analysed data on 11,420 patients receiving unfractionated heparin. Peak aPTT levels recorded during the hospitalization were correlated with clinical outcomes. Multivariable logistic regression models examined the relationship between peak aPTT levels and (i) moderate-to-severe bleeding, (ii) intracerebral haemorrhage, (iii) reinfarction, and (iv) 30-day mortality. Non-linear relationships were explored in the models using cubic spline functions. Higher rates of significant complications were seen in both groups when aPTT levels were <50 s or when levels were >70 s. In the combination therapy group, the relationship between aPTT levels and bleeding appeared accentuated. Reinfarction rates increased gradually as aPTT levels were >70 s in both groups, but the relationships were not statistically significant. Peak aPTT levels <50 s were associated with increased 30-day mortality even after multivariable adjustment.

CONCLUSION

Peak aPTT levels <50 s and >70 s are associated with worse clinical outcomes in the modern era of fibrinolytic therapy; these relationships are different in patients receiving standard reteplase vs. combination therapy.

Protein C levels can be forecasted by global haemostatic tests in critically ill patients and predict long-term survival

INTRODUCTION

We have shown the usefulness of global haemostatic tests International Normalized Ratio (INR) and Activated Partial Thromboplastin Time (APTT) for predicting survival in critically ill patients. Ability to analyse inhibitors protein C and antithrombin is limited to a small number of laboratories and often only during office hours. We therefore studied the usefulness of global haemostatic tests to predict levels of protein C and antithrombin and investigated value of these latter tests in predicting outcome.

PATIENTS/METHODS

Blood samples were collected within 6 h of admission to intensive care unit (ICU) and tested regarding platelet count, INR, and APTT. If platelet count was <100x10(9) L(-1), INR >1.36 and/or APTT >45 s, a second sampling was done within 6 h after the first one for analysis of protein C and antithrombin. Ninety-two patients were included; length of stay at ICU and hospital, survival when leaving ICU and hospital and up to 5 years were recorded.

RESULTS

Using univariate analysis of variance, INR and APTT separately predicted levels of protein C and to some extent antithrombin. Neither platelet count nor any combinations of global haemostatic tests were predictive. Utilising Cox regression, decreased protein C, but not antithrombin, predicted lower survival rate.

CONCLUSIONS

Global haemostatic tests INR and APTT can predict levels of protein C and, though less so, antithrombin. A low protein C level indicated a sinister prognosis in the ICU setting, at the hospital, and after up to 5 years.