OBJECTIVES Transcatheter aortic valve replacement (TAVR) represents a valid treatment for patients with aortic valve stenosis and high or intermediate surgical risk. However, biological transcatheter valves can also experience a structural degeneration after years, and a redo-TAVR procedure (TAVR-in-TAVR) can be a valid option. We revised the current available literature for indications, procedural and technical details and outcome on TAVR-in-TAVR procedures for degenerated TAVR valves. METHODS A systematic search was conducted in the public medical database for scientific articles on TAVR-in-TAVR procedures for degenerated transcatheter valves. Data on demographics, indications, first and second transcatheter valve type and size, mortality, complications and follow-up were extracted and analysed. RESULTS A total of 13 studies (1 multicentre, 3 case series, 9 case reports) were included in this review, with a total amount of 160 patients treated with TAVR-in-TAVR procedures for transcatheter valve failure. The mean age was 74.8 ± 7.8 with 84 males (52.8%). The mean elapsed time from the first TAVR procedure was 58.1 ± 23.4 months. Main indication for TAVR-in-TAVR was pure stenosis (38.4%, with mean gradient of 44.5 ± 18.5 mmHg), regurgitation (31.4%), mixed stenosis and regurgitation (29.5%) and leaflet thrombosis (8.8%). Procedural success rate was 86.8%, with second TAVR valve malposition occurred in 4 cases (2.5%). The hospital mortality rate was 1.25% (2/160). Post-procedural echocardiographic control showed moderate regurgitation in 5.6% of patients (9/160) and residual transvalvular mean gradient ≥20 mmHg in 5% of cases. Postoperative complications included major vascular complications (8.7%), new pacemaker implantation (8.7%), acute kidney failure (3.7%), stroke (0.6%) and coronary obstruction (0.6%). The mean follow-up time was 6 ± 5.6 months with 1 non-cardiovascular death reported. CONCLUSIONS TAVR-in-TAVR represents a valid alternative to standard surgery for the treatment of degenerated transcatheter valves in high-risk patients. Despite these promising results, further studies are required to assess durability and haemodynamic performances of the second TAVR valve. Subj collection 117, 122, 125

中文翻译：

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经导管主动脉瓣置换术治疗先前植入的经导管瓣膜结构退化（TAVR-in-TAVR）：系统评价

目的 经导管主动脉瓣置换术 (TAVR) 代表了主动脉瓣狭窄和高或中等手术风险患者的有效治疗方法。然而，生物经导管瓣膜也可能在多年后经历结构退化，重做 TAVR 程序 (TAVR-in-TAVR) 可能是一个有效的选择。我们修订了当前可用的关于退化 TAVR 瓣膜的 TAVR-in-TAVR 程序的适应症、程序和技术细节以及结果的文献。方法 在公共医学数据库中对退化的经导管瓣膜的 TAVR-in-TAVR 程序的科学文章进行系统搜索。提取和分析了人口统计学、适应症、第一和第二经导管瓣膜类型和大小、死亡率、并发症和随访的数据。结果 共有 13 项研究（1 项多中心，3 个病例系列，9 个病例报告）被纳入本评价，共有 160 名患者接受了 TAVR-in-TAVR 手术治疗经导管瓣膜衰竭。平均年龄为 74.8 ± 7.8，其中 84 名男性 (52.8%)。第一次 TAVR 手术的平均经过时间为 58.1 ± 23.4 个月。TAVR-in-TAVR 的主要适应症是单纯狭窄（38.4%，平均梯度为 44.5 ± 18.5 mmHg）、反流（31.4%）、混合狭窄和反流（29.5%）和小叶血栓形成（8.8%）。手术成功率为86.8%，其中4例（2.5%）发生二次TAVR瓣膜错位。住院死亡率为1.25%（2/160）。术后超声心动图控制显示 5.6% 的患者 (9/160) 存在中度反流，5% 的病例残留跨瓣平均梯度≥20 mmHg。术后并发症包括主要血管并发症（8.7%）、新起搏器植入（8.7%）、急性肾功能衰竭（3.7%）、中风（0.6%）和冠状动脉阻塞（0.6%）。平均随访时间为 6 ± 5.6 个月，报告了 1 例非心血管死亡。结论 TAVR-in-TAVR 代表了标准手术的有效替代方法，用于治疗高危患者的退化经导管瓣膜。尽管取得了这些有希望的结果，但仍需要进一步的研究来评估第二个 TAVR 瓣膜的耐久性和血流动力学性能。主题集合 117, 122, 125 结论 TAVR-in-TAVR 代表了标准手术的有效替代方法，用于治疗高危患者的退化经导管瓣膜。尽管取得了这些有希望的结果，但仍需要进一步的研究来评估第二个 TAVR 瓣膜的耐久性和血流动力学性能。主题集合 117, 122, 125 结论 TAVR-in-TAVR 代表了标准手术的有效替代方法，用于治疗高危患者的退化经导管瓣膜。尽管取得了这些有希望的结果，但仍需要进一步的研究来评估第二个 TAVR 瓣膜的耐久性和血流动力学性能。主题集合 117, 122, 125