A - Parnaparin, dose of 8,500 IU aXa taken subcutaneously once a day for 10 days B - Parnaparin, dose of 8,500 IU aXa per day for 10 days followed by Parnaparin 6,400 IU aXa per day for the subsequent three weeks. C - Parnaparin, dose of 4,250 IU aXa per day for 30 days Elastic compression treatment will be recommended with special stocking and/or elastic bandaging with compression to the ankles of 20-40 mmHg, where not contraindicated.