Incomplete endothelialization after LAAC
CCTA can not only display PDL but also incomplete endothelialization at the distal site of LAA by signs of contrast enhancement post device implantation, while TEE is not available.
Previous report showed that satisfactory endothelialization could be achieved within 45 days after LAAC device implantation in the canine model[17]. However, several clinical observation studies found that delayed endothelialization or incomplete endothelialization of LAAC device might occur in some patients, which was linked with increased risk of DRT, stroke and systemic embolic events[18].
In our study, CCTA performed at 6 months post LAAC showed that among 51 patients without PDL, complete device endothelialization was achieved in 44 patients (86.3%) , while there were 7 patients with incomplete device endothelialization (13.7%). This result is in line with a previous study, which reported incomplete endothelialization in 7 out of 79 patients (8.9%) at 3 months post LAAC with Watchman device[13].
The clinical implication of PDL and incomplete endothelialization defined by CCTA in our patient remains to be determined during the planned long-term follow-up. It sounds that both PDL and incomplete endothelialization do not affect short-term outcome of patients post LAAC, since adverse events were similar and rare post procedure between patients with or without PDL and with or without incomplete endothelialization during the 6 months follow-up post LAAC and AFCA.
Our patients will undergo long-term follow-up to see if the complete endothelialization could be achieved or not in the 7 patients with incomplete endothelialization, and to compare the outcome of patients among various groups. Prospective long-term follow-up studies with large patient cohort are definitively needed to validate the value of CTTA on defining post LAAC PDL and incomplete endothelialization, CCTA derived maximum diameter of LAA orifice on predicting post LAAC PDL, and the clinical implication on outcome including the incidence of stroke, DRT or systemic embolic events of PDL and incomplete endothelialization post LAAC. Moreover, future studies should also evaluate if the maximum diameter of LAA orifice could be used as a screening index for AF patients before LAAC on risk stratification of post LAAC PDL and incomplete endothelialization and to see if this index could be integrated to other parameters to establish a compressive coding system for individualized decision making regarding the postoperative anticoagulation program.