D-MP04-01 - First In Vivo Experience Using Polarization Sensitive Optical Coherence Tomography (PSOCT) During Catheter Ablation In The Left Atrium (ID 848)
X. Zhao: Nothing relevant to disclose.
Background: RF catheter ablation is an important tool for the treatment of AF. Yet, the operator receives little real-time tissue information for monitoring lesion formation. Polarization sensitive optical coherence tomography (PSOCT) can be used to determine tissue necrosis; however, its ability to monitor lesion formation in vivo during LA RF ablation has not been reported.
Objective: Evaluate the ability of PSOCT to monitor lesion transmurality in vivo during LA RF ablation.
Methods: PSOCT imaging and RF ablation were performed in pig (n=4) using a catheter with a forward facing imaging window and 4 mm ablation tip. Lesions (n=34) were applied for 45 secs, 40W, 65C at all sites, including the LAA (n=13), mitral annulus (n=3), septum (n=1), LA roof (n=3), and PLA (n=14). Actual lesion transmurality was determined with the viability stain TTC. For each corresponding site, PSOCT transmurality was determined by the loss of tissue birefringence, which signifies a loss of cellular structure during thermal ablation.
Results: Based on TTC staining, the prevalence of transmural lesions (n=33) over non-transmural lesions (n=1) was 94%. For all lesions with analyzable PSOCT images (n=17, 50%), PSOCT transmurality was highly correlated with TTC transmurality. PSOCT had a sensitivity of 88% (14 of 16 tested positive) and a specificity of 100% (1 of 1 tested negative). Furthermore, PSOCT had a high positive predictive value of 100% (73%-100% CI), but a low negative predictive value of 33% (2%-87% CI). At lesions where PSOCT images were not analyzable, most (n=14, 41%) had suboptimal imaging window stability due to non-perpendicular view angle or catheter motion. Most of these sites were at the pulmonary vein ostia and septal aspect of the LAA. Finally, a small percentage of sites (n=6, 9%) had stable images, but were not analyzable because tissue thickness was beyond the PSOCT view depth.
Conclusion: This is the first report we are aware of using PSOCT in vivo to monitor RF lesion transmurality in the LA. PSOCT exhibited high sensitivity and positive predictive value. As a first experience, these data are limited but encouraging for larger studies. Once the challenges of image stability are overcome, tissue birefringence measured using PSOCT may be a robust indicator of lesion formation.