Fraxiparine is nadroparin (not available in the US by the way), an anticoagulant administered by injection. Marevan is sodium warfarin, an oral anticoagulant. Both may be started at the same time in the acute stage of thrombosis, then the patient is weaned off the injections and is discharged on the oral medication only. It is also common for the patient to start on the injections only, followed by an overlap period when the oral anticoagulant is used, and then injections are stopped and the oral treatment takes over. It is not 100% clear from your text what the exact chronology was - so I would remain *vague* and use "in combination with".

http://ang.sagepub.com/cgi/content/abstract/57/4/418
Immediately after diagnosis, all patients were treated with nadroparin calcium and sodium warfarin. Heparin treatment was withdrawn after 5–6 days of treatment, when the international normalized ratio (INR) was stabilized between 2 and 3. Each group was divided into 2 subgroups receiving anticoagulation treatment for 6 or 12 weeks, respectively.