Occlusion assessment tools
Optimal occlusion of PV is a prerequisite of successful PVI. Hence, the PV occlusion assessment is of crucial value in CBA procedure. Currently, pulmonary venography is regarded as the standard criterion, although various alternatives have been proposed to reduce contrast or fluoroscopy use, such as intracardiac echocardiography (ICE)16, transesophageal echocardiography (TEE)17, 18, and change of the pressure waveform recorded at the CB tip during occlusion19, 20.
Also, KODEX-EPD system is equipped with various tools for occlusion assessment11, 21-23. Cauti FM et al11 demonstrated high accuracy of the integrated occlusion verification tool (the same technique as baseline tool in our study) in version 1.4.5 and 1.4.6. The novel injection-based workflow, available since 1.4.7 software version, uses contrast medium as a dielectric insulator and measures dielectric changes across the electrodes of the circular mapping catheter, which is expected to have a higher accuracy compared with the baseline tool, especially for detection of smaller leaks. These two tools for detecting occlusion can be used together or independently. In the present study, both tools were tested in 23 patients receiving CBA. We found that baseline tool showed a higher overall sensitivity, while injection tool showed a higher overall specificity. This finding indicates that baseline tool may serve as a real-time assessment tool, while injection tool may serve as a final confirmation tool for PV occlusion.
Notably, the discrepancies between both tools were not uncommon. Our findings indicated that different tools might be suitable in different PVs. For example, the baseline tool was more effective in LSPV and RSPV. The reasons were: i) most attempts of LSPV and RSPV could achieve optimal occlusion in both tools as well as in pulmonary venography; ii) in cryoablation of RSPV, minimal leak was encouraged, also known as “proximal-seal” technique24, to reduce the risk of PNI, whereas the pursuit of complete occlusion with the injection tool might lead to overfreezing and increase the risk of PNI. In contrast, complete occlusion in inferior PVs with the injection tool was associated with lower nadir temperature and longer thaw time, which might result in more durable PVI.