I had extremely chronic DVT eleven years ago. My doctor gave me Warfarin for months and then took me off of it. My next check up showed my INR was too high so I was prescribed a bigger dose of Warfarin. My doctor didn't know what else to do. Real long story short is I ended up at Bumrungrad at the Horizon Cancer Clinic and Dr. Harit gave me a complete physical and said he had never seen a case as bad as mine. He prescribed Xarelto, one pill a day for six months. Back then Xarelto was 800 Baht per pill but it got the job done !!! All up I spent 20 months under medical supervision. I wear a full length compression stocking daily. I have had two doctors recommend that if I were to fly in excess of 3 hours I should inject myself with Heparin every 3 hours during a long haul flight along with drinking a lot of water, compression stocking and walk around the plane frequently. I hope this information is of some help to you !!!