CA and ICE
All the patients were administered oral anticoagulants more than 3 weeks before CA. Novel oral anticoagulants other than dabigatran were changed to dabigatran on the day of surgery and the day following CA. If the anticoagulants used were dabigatran or warfarin, their intake was continued throughout the perioperative period. CA was performed under general anesthesia. Activated clotting time (ACT) was measured using blood samples obtained venously every 15-30 min during the procedure; this value was maintained at 300-350 s using unfractionated heparin. An ICE probe (ViewFlex Xtra ICE catheter, Abbott Laboratories, Illinois, USA or ACUSON AcuNav, Johnson and Johnson, New Jersey, USA) was inserted from the right or left femoral vein through a long sheath (SL0, Abbott Laboratories, Illinois, USA). After the transseptal approach, we placed the ICE probe in the LA, and the probe was turned to scan the entire LA and LAA before CA performance in the LA. The LAA was visualized from the body of the LA. If there was no thrombus in the LAA, CA was performed. Meanwhile, if a thrombus was suspected on ICE, CA in the LA was abandoned. The thrombi evaluated by ICE were defined as circumscribed and uniformly echo-dense intra-cavity masses distinct from the underlying endocardium and pectinate muscles.
Using the ICE probe, the velocity of blood flow was estimated inside the LAA. These data were obtained using pulse-Doppler imaging. Sample volumes were positioned within 1 cm of the orifice of the LAA and the velocities were assessed during AF. The peak emptying velocities of the LAA were averaged over a minimum of five consecutive cardiac cycles (with each R-R interval).9
Three-dimensional CT (3DCT) of the LA was made of images of early-pCT for LA reconstruction. These LA images were merged with a 3D mapping system during CA.
We also assessed the presence of symptomatic stroke events during the perioperative period.