ICE/IVUS images analysis
Out of the 48 PV cross-sections, 3 were discarded because of poor
quality and 45 (28 ICE and 17 IVUS frames) were considered adequate for
quantitative analysis.
Compared to the IVUS cross-sections, the ICE ones showed larger lumen
and vessel diameters and areas, larger wall thicknesses and
significantly lower lumen and vessel sphericity indexes, indicative of
more oval/elliptical shape of both lumen and vessel contours (Table 2).
Of note, median pre- and post-ablation wall thickness index percentage
(WTI%) and muscular sleeve thicknesses did not differ between ICE and
IVUS-imaged PVs.
As detailed in Table 3, statistically significant increases of mean wall
thickness, wall thickness index (WTI) and WTI%, suggestive of acute
wall thickening, were observed after ablation in both ICE and IVUS
cross-sections. A significant reduction of the thickness of the muscular
sleeve was also observed after ablation [ICE cross-sections: median
(IQR) percentage reduction= 8.2 (0-45.9) %; IVUS cross-sections: median
(IQR) percentage reduction= 31.68 (14.54-81.64) %], with complete
disappearance of the muscular sleeve after ablation in 6 PVs out of 45.
When grouping by ablation technology used for PVI (RF, cryo or laser),
the increase in WTI% was observed only after RF treatment (p = 0.003)
and laser treatment (p = 0.003), whilst no significant changes in wall
thickness were observed after cryo ablation (p = 0.69) (Figure 3, Table
4).
A single case of vessel dissection was documented after ablation (right
inferior pulmonary vein after cryoballoon ablation) (Figure 4).