Reliable identification of 'truly low' thromboembolic risk in patients initially diagnosed with 'lone' atrial fibrillation:The Belgrade atrial fibrillation study

Background The CHA 2 DS 2-VASc schema has recently been introduced to complement the CHADS2 score and improve the identification of atrial fibrillation （AF） patients at ＇truly low risk＇ for thromboembolism.We tested the predictive ability of the CHA 2 DS 2-VASc,CHADS2 and van Walraven risk stratification schemes in a cohort of ＇lone＇ AF patients with a 12-year follow-up.Methods and Results We conducted a registry-based,observational cohort study of 345 patients initially diagnosed with ＇lone＇ AF between 1992 and 2007.At baseline,all patients had the CHADS2 and van Walraven scores of 0,and 262 （75.9%） had a CHA 2 DS 2VASc score=0.During follow-up （or within a year prior to stroke）,228 （66.1%）,234 （67.8%） and 150 patients （43.5%） retained the CHADS2,van Walraven and CHA 2 DS 2VASc scores of 0,respectively.The overall rate of ischemic stroke was 0.19 （95%CI：0.18-0.20） per 100 patient-years.In the multivariable analysis,only the CHA 2 DS 2-VASc score of 0 was significantly related to the absence of stroke （OR 5.1,95%CI：1.5-16.8,P=0.008）.Only the CHA 2 DS 2-VASc score had a significant prediction ability （c-statistic 0.72 [0.61-0.84],P=0.031）.Conclusions The CHA 2 DS 2-VASc score reliably identified the ＇lone＇ AF patients who were at ＇truly low risk＇ for thromboembolism,and was the only tested risk stratification scheme with a significant predictive ability for thromboembolism amongst lone AF patients.

Numeric modelling and risk assessment of pollutions in the Chinese Bohai Sea

To simulate the dynamic process of total nitrogen(TN) in seas, numerical modelling combined with the adjoint method is implemented in this study. Because nonpoint source terms(ST) and initial values(IV) of TN are essential but difficult to determine, the adjoint method was applied to a numerical model, and the ST and IV terms of TN were inverted via routine monitoring data in the Bohai Sea. In twin experiments, the adjoint method was capable of inverting the prescribed spatio-temporally distributed ST and the spatial distributed IV. In practical experiments, the results demonstrated that the simulation precision with ST inversion was higher than that with IV inversion and was accurate with joint initial values and source term(IST) inversion. This result indicates that nonpoint source TN is essential for the simulation of TN concentration. Furthermore, the simulated results indicate that the pollution in three bays of the Bohai Sea is rather severe. The model in this study is not specific to the Bohai Sea and can be generalized to other areas, such as the Beibu Gulf. These findings may assist in the development of cost-effective controls for accidental or planned industrial pollutant releases into coastal waters.