The largest multicenter randomized trial to date of CT angiography before left atrial appendage closure (LAAC) to treat atrial fibrillation has added to the evidence that the imaging technique on top of transesophageal echocardiography achieves a higher degree of short- and long-term success than TEE alone.

The results are from a subanalysis of the Swiss-Apero trial, a randomized comparative trial of the Watchman and Amulet devices for LAAC, which published results in Circulation.

“Our observational data support to use of CT for LAAC procedure planning,” senior investigator Lorenz Räber, MD, PhD, said in an interview. “This is not very surprising given the high variability of the LAA anatomy and the associated complexity of the procedure.” Dr. Räber is director of the catheterization laboratory at Inselspital, Bern (Switzerland) University Hospital.

The study, published online in JACC: Cardiovascular Interventions, included 219 LAAC procedures in which the operators performed coronary CT angiography (CTTA) beforehand. When the investigators designed the study, LAAC procedures were typically planned using TEE alone, and so participating operators were blinded to preprocedural CCTA imaging. Soon after the study launch, European cardiology societies issued a consensus statement that included CCTA as an option for procedure planning. So the Swiss-Apero investigators changed the subanalysis protocol to unblind the operators – that is, they were permitted to plan LAAC procedures with CCTA imaging in addition to TEE. In this subanalysis, most patients had implantation with blinding to CCTA (57.9% vs. 41.2%).

Study results

The subanalysis determined that operator unblinding to preprocedural CCTA resulted in better success with LAAC, both in the short term, at 93.5% vs. 81.1% (P = .009; adjusted odds ratio, 2.76; 95% confidence interval, 1.05-7.29; P = .40) and the long term, at 83.7% vs. 72.4% (P = .050; aOR, 2.12; 95% CI, 1.03-4.35; P = .041).

Dr. Räber noted that this is only the third study to date that examined the potential impact of preprocedural CCTA plus TEE. One was a small study of 24 consecutive LAAC procedures with the Watchman device that compared TEE alone and CCTA plus TEE, finding better outcomes in the group that had both imaging modalities . A larger, single-center cohort study of 485 LAAC Watchman procedures found that CCTA resulted in faster operation times and higher successful device implantation rates, but no significant difference in procedural complications.