* patients admitted directly to an intensive care unit; * estimated creatinine clearance \<15 ml/min/1.73m2; * patients needing anticoagulant for prior indication; * participants involved in other clinical trials; * any other significant disease or disorder which, in the opinion of the investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.

* patients admitted directly to an intensive care unit; * estimated creatinine clearance \<15 ml/min/1.73m2; * patients needing anticoagulant for prior indication; * participants involved in other clinical trials; * any other significant disease or disorder which, in the opinion of the investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.

- patients admitted directly to an intensive care unit; - estimated creatinine clearance <15 ml/min/1.73m2; - patients needing anticoagulant for prior indication; - participants involved in other clinical trials; - any other significant disease or disorder which, in the opinion of the investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.

- patients admitted directly to an intensive care unit; - estimated creatinine clearance <15 ml/min/1.73m2; - patients needing anticoagulant for prior indication; - participants involved in other clinical trials; - any other significant disease or disorder which, in the opinion of the investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.