BACKGROUND The clinical utilization of leadless pacemakers (LPs) as an alternative to traditional transvenous pacemakers is likely to increase with the advent of dual-chamber LP systems. Since device retrieval to allow LP upgrade or replacement will become an important capability, the first such dual-chamber, helix-fixation LP system (Aveir DR; Abbott, Abbott Park, IL) was specifically designed to allow catheter-based retrieval. In this study, the preclinical performance and safety of retrieving chronically implanted dual-chamber LPs was evaluated. METHODS Atrial and ventricular LPs were implanted in the right atrial appendage and right ventricular apex of 9 healthy ovine subjects. After ≈2 years, the LPs were retrieved using a dedicated transvenous retrieval catheter (Aveir Retrieval Catheter; Abbott) by snaring, docking, and unscrewing from the myocardium. Comprehensive necropsy/histopathology studies were conducted to evaluate device- and procedure-related outcomes. RESULTS At a median of 1.9 years postimplant (range, 1.8-2.6), all 18 of 18 (100%) LPs were retrieved from 9 ovine subjects without complications. The median retrieval procedure duration for both LPs, from first-catheter-in to last-catheter-out, was 13.3 minutes (range, 2.5-36.4). Postretrieval, all right atrial, and right ventricular implant sites demonstrated minimal tissue disruption, with intact fibrous tissue limited to the distal device body. No significant device-related trauma, perforation, pericardial effusion, right heart or tricuspid valve injury, or chronic pulmonary thromboembolism were observed at necropsy. CONCLUSIONS This preclinical study demonstrated the safe and effective retrieval of chronically implanted, helix-fixation, dual-chamber LP systems, paving the way for clinical studies of LP retrieval.

中文翻译：

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在绵羊模型中回收长期植入的双腔无引线起搏器。

背景技术随着双腔 LP 系统的出现，无引线起搏器（LP）作为传统经静脉起搏器的替代品的临床应用可能会增加。由于允许 LP 升级或更换的设备检索将成为一项重要功能，因此第一个此类双室螺旋固定 LP 系统（Aveir DR；Abbott，Abbott Park，IL）专门设计用于允许基于导管的检索。在这项研究中，评估了回收长期植入的双腔LP的临床前性能和安全性。方法 将心房和心室 LP 植入 9 只健康绵羊受试者的右心耳和右心室心尖。约 2 年后，使用专用的经静脉回收导管（Aveir 回收导管；Abbott）通过圈套、对接和从心肌旋出来回收 LP。进行了全面的尸检/组织病理学研究，以评估与设备和程序相关的结果。结果 植入后平均 1.9 年（范围为 1.8-2.6），从 9 名绵羊受试者中取出 18 个 LP 中的全部 18 个（100%），没有出现并发症。两个 LP 的中位取出过程持续时间（从第一个导管插入到最后一个导管取出）为 13.3 分钟（范围：2.5-36.4）。取出后，所有右心房和右心室植入部位均显示出最小的组织破坏，完整的纤维组织仅限于远端装置主体。尸检时未观察到明显的装置相关创伤、穿孔、心包积液、右心或三尖瓣损伤或慢性肺血栓栓塞。结论 这项临床前研究证明了长期植入、螺旋固定、双腔 LP 系统的安全有效回收，为 LP 回收的临床研究铺平了道路。