Influence of the ratio between radial artery inner diameter and sheath outer diameter on radial artery flow after transradial coronary intervention.

To test the feasibility of using guiding catheters equal to or greater than 7 Fr in transradial coronary intervention (TRI), we measured the inner diameter of the radial artery (RA) and its flow using two-dimensional ultrasound and Doppler examinations before and after TRI in 250 Japanese patients. The incidence of severe flow reduction of the RA after TRI was 6.8% on average (7.2%, 4.7%, and 8.3% in patients with 6, 7, and 8 Fr sheaths used, respectively), which increased from 4.0% to 13.0% (P=0.0113) if the ratio of the RA inner diameter/sheath outer diameter was less than 1.0. The frequency of this ratio (> or = 1.0) for 7 and 8 Fr sheaths was 71.5% and 44.9% in male patients and 40.3 and 24.0% in female patients, respectively. We conclude that the use of guiding catheters equal to or greater than 7 Fr in the radial artery is feasible in selected patients.