Medtronic, Inc.
Int Heart J. 2023 Jul 29;64(4):724-731. doi: 10.1536/ihj.22-553. Epub 2023 Jul 14.
The extravascular implantable cardioverter-defibrillator (EV ICD) with lead implantation in the substernal space may provide clinical advantages over transvenous and subcutaneous systems. This is the first reported examination of substernal infection in large animals implanted with the EV ICD system.The system was implanted in 13 large animals (canine, porcine, and ovine). The porcine were co-implanted with a transvenous cardiac resynchronization therapy with defibrillator (CRT-D) system. Infection was promoted through a cadence of immunosuppressive monitors and study interventions. The animals were monitored for clinical presentation of infection over 12-18 weeks, and cultures were collected to confirm infection. Treatment was bifurcated: 1) some infections were treated only with antibiotics ( "antibiotics only" ), whereas 2) some infections were treated with system removal and antibiotics ( "antibiotics + explant" ). Histopathology was conducted at the study closure.Five infections were confirmed over the course of the study, four of which involved infection of the EV ICD system and one infection of only the concomitantly implanted transvenous CRT-D system without EV ICD-related infection. Among the four EV ICD infections, two of two infections treated with antibiotics only did not resolve whereas two of two infections treated with antibiotics + explant resolved, as shown by histology. The transvenous CRT-D system infection progressed to septicemia and endocarditis, requiring early study discontinuation. No EV ICD-related infection progressed to blood stream infection, and the sternal bone did not become infected when infection was present in the substernal tissues.The study findings suggest that EV ICD-related infections are treatable with system removal and antibiotic therapy.
经静脉植入式心脏复律除颤器（EV ICD）和心外膜导联植入术可能为临床带来优于经静脉和皮下系统的优势。这是首次报道在植入 EV ICD 系统的大型动物中发生心外膜感染的情况。该系统在 13 只大型动物（犬、猪和羊）中进行了植入。猪同时植入了经静脉心脏再同步治疗除颤器（CRT-D）系统。通过免疫抑制监测器和研究干预来促进感染。监测动物是否有感染的临床症状，持续 12-18 周，并采集培养物以确认感染。治疗分为两种方案：1）一些感染仅用抗生素治疗（“仅用抗生素”），而 2）一些感染用系统去除和抗生素治疗（“抗生素+取出”）。研究结束时进行了组织病理学检查。在研究过程中确认了 5 例感染，其中 4 例涉及 EV ICD 系统感染，1 例仅涉及同时植入的经静脉 CRT-D 系统感染，无 EV ICD 相关感染。在 4 例 EV ICD 感染中，仅用抗生素治疗的 2 例感染中，有 2 例未得到解决，而用抗生素+取出治疗的 2 例感染中，有 2 例得到解决，组织病理学显示。经静脉 CRT-D 系统感染进展为败血症和心内膜炎，需要提前终止研究。没有 EV ICD 相关感染进展为血流感染，并且当心外膜组织发生感染时，胸骨没有感染。研究结果表明，EV ICD 相关感染可以通过系统去除和抗生素治疗来治疗。
