Abstract： Objective To observe the clinical safety of dual axis rotational coronary angiography (DARCA) in the diagnosis of coronary artery disease in Chinese population.Methods From March to December in 2010,74 patients undergoing diagnostic DARCA were enrolled.The improved isocentering technique was adopted in 34 of the patients at the end of the study during DARCA.Blood pressure,heart rate and symptoms were recorded immediately before-and-after contrast injections.Contrast dose,radiation exposure and procedure time for DARCA were recorded.Continuous variable data were analyzed using Student＇s t test,if normality assumption was violated,rank sum test would be used.Categorical variables were analyzed using x2 test.Results ( 1 ) Clinical safety:There was no chest pain documented during or immediately post-injection for all patients.Only 1 patient ( 1 ％ ) had an attack of ventricular tachycardia immediately after the contrast injection and then relieved automatically.Pre and post-injection systolic blood pressure values of left coronary artery were statistically different [ ( 116 ± 20 ) mm Hg vs.( 111 + 18) mm Hg( 1 mm Hg =0.133 kPa),t =3.303,P =0.001 ],and heart rates differed,too [ 73 ( 65- 84)bpm vs.71(64-78) bpm,Z =-4.789,P =0.001 ],but that imposed no clinical significance.(2)Contrast dose,radiation dose and procedure time:The mean contrast utilization,radiation dose and procedure time for DARCA were 28 (25-34) ml,8979 ( 6733-12 363 ) mGycm2 and 200 (164-270) s.Compared with conventional DARCA,improved isocentering technique during DARCA had less radiation exposure and procedure time in left coronary artery angiography and the whole coronary artery angiography [ left coronary artery angiographic radiation exposure:4004 (2932-5772) mGycm2 vs.5808 (4798- 8838) mGycm2,Z =-3.471,P =0.001 ;total radiation exposure:(8116 +2493) mGycm2 vs.( 11 371 ±4122) mGycm2,t =-4.176,P =0.001 ; left coronary artery angiographic procedure time:120 ( 80-180)s vs.150(126-214) s,Z =- 2.836,P =0.005; total procedure time:180 (139-240) s vs.220( 186-308 )s,Z =-3.004,P =0.003 ],but there was no statistically difference in contrast utilization [30(25-35) ml vs.27(25-34)ml,Z=-0.906,P=0.365].Conclusion This study demonstrates clinical safety of DARCA in the diagnosis of coronary artery disease in Chinese population.Compared with conventional isocentering technique of DARCA,improved isocentering technique can significantly reduce radiation exposure and procedure time on the basis of simplified operation,and replace the conventional isocentering technique,but randomized double-blind controlled studies should be conducted.