Computed tomography and CA
CT was performed during the AF rhythm and ICE was used to visualize the LAA in all the patients. No CD was found in both the early and late phases in 260 patients (86%). Of the 40 patients who exhibited CDs on early-pCT, 34 (11%) did not have them during the late phase (Figure 1). The average dose length product was 2166.22±224.27 mGycm, which of those only in the early phase was 1084.88±114.25 mGycm and those in the late phase was 1031.34±133.46 mGycm. The total contrast medium which used for CT scanning was 1810.46±384.95 mg of Iopamiro.
Among the 294 patients without a CD on late-pCT, CA was performed on schedule. The absence of thrombus was reconfirmed using ICE performed from the LA (Table 2). In one patient, the LAA could not be visualized clearly from the body of the LA. The ICE was inserted into the left superior pulmonary vein, which enabled to observe the whole LAA.
CDs existed in both the early and late phases of pCT in the remaining six patients (2%, Figures 2A and 2B). None of the patients showed CDs only on late-pCT. There CDs were located at the entrance of the LAA in 1, outer edge in 2, inner edge in 2 and the residual LAA portion after LAA clipping in 1. In these six patients, CA was cancelled, and the type of anticoagulant was changed or the dose was increased in the case of warfarin use. Follow-up CT was performed after 3-7 months. We observed CD disappearance on subsequent late-pCT under the same CT conditions (Figure 2C); following this, CA was performed. The absence of thrombi was confirmed using ICE in all six patients. Among them, four patients were also performed TEE after the CT scanning, and thrombi were observed in all patients. One of six patient with CDs in both the early and late phases required two changes in the anticoagulant used for CD disappearance (Figure 3); in the remaining five patients, the anticoagulant type was altered once.
In the whole population, six patients had also undergone CT in the supine position (sCT) within 3 days before pCT and CD presence was suspected. These CDs disappeared on late-pCT in three patients (Figure 4) and no thrombus was detected on ICE during CA, as mentioned previously.
ICE imaging was performed during the AF rhythm in all patients. The average duration between first CT scanning to catheter ablation was 9.4±7.5 days. The first subsequent CT in patients with CDs was performed in median 68 (38-131) days, and for one patient, another CT was needed for the disappearance of a contrast defect 58 days after seconds CT scanning (Figure 3D). None of the patients had complications related to CT, and no symptomatic stroke events were observed during the perioperative period of CA.