Objectives To observe the safety and availability of anticoagulation of low-intensity warfarin anticoagulant therapy in AF patients with high stroke risk and high risk of bleeding applying CHA₂DS₂VASc stroke risk score and bleeding risk scoring HAS-BLED (CHA₂DS₂VASc ≥1 and HAS-BLED ≥3)by using the scoring system in the 2010 ESC Guideline.

Methods 99 AF patients who has the stroke risk scoring CHA₂DS₂VASc≥1 and HAS-BLED score ≥3 were selected randomly and divided into two groups: group 1 of 45 cases SPAF was treated by a standard intensity warfarin therapy (2.0< INR≤3.0), and the other group was treated by a low intensity warfarin therapy (1.6≤INR≤2.0). All the patients need to do the routine blood test, urinary occult blood test, liver and renal function test, blood sugar levels test, fat test, and the heart colour without left atrial thrombosis test. We need to record the patient’s age, gender, weight, basic disease of AF, the disease time of AF, whether the patient has taken the antithrombotic drugs or not, whether they has the history of bleeding or thrombosis or any other diseases combined with such as high blood pressure, diabetes and coronary artery disease.

The enrolled patients were taking 2.5mg Warfarin with low molecular weight heparin (LMWH) at the first 3-5 days, and test the INR data every 2 or 3 days at the first two weeks. Adjust the dose of warfarin until the INR was relatively stable according to the INR data. Then test the INR data once a month for 12 months. Observing the incidence of stroke and bleeding events of the two groups. The results were statistically analyzed with X2 test (x ± s).

Results There were 99 selected patients and the duration of follow-up is 1 year. The standard intensity warfarin therapy group has 45 patients which including 24 males and 21 females with the average age 62.18 years old (2.0< INR≤3.0).the maintain dose of Warfarin was 3.08 ± 0.25mg/d, time for INR first reaching the standard was 13.07 ± 4 days, and the stable value was 2.48 ± 0.19. Among them, there is one case of the cerebral embolism, one case of the peripheral artery embolism with 4.4% of stroke incidence. And in this group, 2 cases of skin bleeding, 5 cases of s gingival bleeding, 2 cases of digestive canal bleeding, one case of urinary system bleeding, one case of the intracerebral hemorrhage with 24.4% of the bleeding incidence. There are 54 patients in the low intensity warfarin therapy group which has including 28 males and 26 females with the average age of 62.83 years old (1.6≤INR≤2.0). During the treatment, the maintain dose of Warfarin was 2.55 ± 0.11mg/d, time for INR first reaching the standard was 11.78 ± 3.47 days, and the stable value was 1.86 ± 0.07. There is one case of transient cerebral ischaemia, 2 cases of cerebral embolism, one case of peripheral artery embolism with 7.4% of the stroke incidence. In this group, one case of skin bleeding, 3 cases of gingival bleeding, one case of digestive canal bleeding with 9.3% of the bleeding incidence. The incidence of stroke between these two groups was not statistically significant (P = 0.848, P>0.05). The incidence of bleeding for standard group is higher than the low group which has marked a big difference (P = 0.041, P<0.05).

Conclusions AF patients with high risk of bleeding (CHA₂DS₂VASc≥1 and HAS-BLED score≥3) can be treated by the low intensity anticoagulation with warfarin safely and reliably, which can suppress thrombosis and embolism effectively and not increase serious hemorrhage.