In Reply We thank Ngo et al for their interest in our article.1 Our study reported the rate of acute complications, device complications at 6 months, and need for system revision at 6 months among patients implanted with a leadless VVI vs transvenous VVI pacemaker using Medicare claims data.
An acknowledged limitation of claims-based studies is that without clinical adjudication to determine whether a complication is procedure-related or device-related, misattribution or overattribution is possible. For the Micra Coverage with Evidence (CED) study,1 an outcomes validation analysis found 95% agreement between reported adverse events in patients coenrolled in the Micra Postapproval Registry (PAR).2 However, for certain adverse events, there was a higher rate of disagreement, with the CED study identifying a greater number of adverse events, including arteriovenous fistula (50%), pulmonary embolism (67%), hemorrhage and hematoma (75%), and deep vein thrombosis (100%), as these codes are not device specific and may be related to other concomitant interventions. In brief, claims-based studies may overestimate adverse events; notably, the 30-day complication rates reported in our study are similar to rates reported in other claims-based analyses.3 From a safety perspective, it is reassuring that the rate of pericardial effusion reported in the Micra CED study (0.8%) is in line with the observed rate seen with the Micra PAR (0.77%), which has trended down over time compared with the Micra Investigational Device Exemption (IDE) trial (1.8% pericardial effusion rate).4,5