Background: Radial artery (RA) occlusion (RAO) is not rare in patients undergoing coronary intervention by transradial approach (TRCI).Predictors of and prevention from RAO have not been systematically studied.This study aimed to analyze the risk factors of the weakness of RA pulsation (RAP) and its predictive value for RAO after TRCI, and simultaneously to describe a feasible and effective approach to maintain RA patency.Methods: Between June 2006 and March 2010, all patients who underwent TRCI were classified according to the weakness of RAP after removing compression bandage with confirmation by Doppler ultrasound for the first 30 consecutive patients.Among a total of 2658 patients studied, 187 (7%) patients having a weaker RAP were prospectively monitored.At 1 h after bandage removal, the ulnar artery in puncture side of all patients was blocked with manual compression to favor brachial and collateral artery blood flow through the RA until a good RAP was restored.The primary analysis was the occurrence of RAO.Results: Doppler ultrasound demonstrated the significant reduction of both systolic velocity (61.24 ± 3.95 cm/s vs.72.31 ± 3.57 cm/s) and diastolic velocity (1.83 ± 0.32 cm/s vs.17.77 ± 3.97 cm/s) in RA at access side as compared to the contralateral RA (all P < 0.001),but these velocities in ipsilateral ulnar artery (81.2 ± 2.16 cm/s and 13.1 ± 2.86 cm/s, respectively) increased profoundly.The average time of ulnar artery compression was 4.1 ± 1.2 h (ranged 2.5-6.5 h).There were two patients experienced persistent RAO with a success rate of 98.9% and RAO in 0.075% of patients after ulnar artery compression was applied.The pulsation of the ulnar artery after compression was removed had not been influenced by the compression.Conclusions: After intervention using TRCI approach, the presence of a weaker RAP is an indicator of imminent RAO.The continuing compression of ipsilateral ulnar artery is an effective approach to maintain RA patency.