SVC area
Figure 2B shows a comparison of the SVC area before and after the ablation process. The mean SVC area at baseline was 2.50 ± 0.94 cm2. By contrast, the SVC area after the ablation was reduced to 2.19 ± 0.82 cm2. Trivial (0–25%), mild (25–50%), moderate (50–75%) stenoses were observed in 73 (78%), 13 (14%), and 5 (5%) patients, respectively. No severe stenosis (dimensional reduction >75%) was observed in this study. The relevant application times are plotted in Figure 3. No significant differences were noted among the three groups, and the degree of SVC narrowing was not found to be significantly correlated with the application time.
Eight patients associated with 18 mild and moderate narrowing cases (1.56± 0.42 cm2) were followed further at 20 ± 4.2 months after the ablation process, and the SVC area were estimated again. The mean SVC area shown in Figure 4 was 1.80 ± 0.57 cm2. This is slightly larger compared to the value recorded four months after the ablation process. SVC narrowing did not progress with the exception of two cases that did not develop symptomatic severe stenosis.