JAMA：单腔ICD植入用于无起搏器适应证患者一级预防优于双腔ICD

5月15日JAMA刊发的一项研究报告称，在接受可植入式埋藏式心律转复除颤器(ICD)用作一级预防的无起搏适应证患者人群中发现，与应用单腔ICD相比，双腔ICD没有表现出任何优势。

这项回顾性队列研究纳入了32,000余例美国患者，其植入单腔和双腔ICD患者的1年死亡率、心衰或全因住院率均未见显著差异。丹佛健康医学中心的Pamela N. Peterson博士及其同事报告称。然而，双腔ICD却存在着重要的缺点：感染和导线脱位等并发症发生率较高。此外，由于双腔ICD植入比较复杂且费时，因此费用较高，并且术后装置功能障碍也更为常见。

Peterson博士及其合作者称，“因此，对于没有明显起搏适应证的患者而言，植入双腔ICD作为一级预防手段的决策应谨慎。”他们之所以进行这项队列研究，是因为目前尚不清楚双腔与单腔ICD长期安全性和结局是否存在差异。研究者强调，“虽然没有足够的证据支持使用更为昂贵的器械，但在当前实践中双腔ICD却更为常用。”

研究人员利用美国国家心血管数据注册(NCDR)研究中ICD登记资料，确认了2006~2009年间在全美1,270家医院接受ICDs植入术的32,034例患者，其中19,788 例(62%)植入双腔ICD，12,246例(38%)植入单腔ICD。所有受试患者植入ICD均仅作为一级预防，且均不具有任何起搏适应证。

研究者通过分析原始数据，对所有严重并发症发生率进行了考察，包括植入术后30天内需胸管治疗的气胸、需输血或抽吸的血肿、心包填塞以及术后90天内导线修正、装置相关感染和再次ICD植入。他们发现，双腔ICD患者的上述所有并发症的未校正发生率均较高。单腔与双腔ICD的最大差异表现在需要再次手术系统修正的ICD装置功能故障，这也是最常见的并发症。单腔与双腔ICD植入组患者1年未校正心衰住院率(14.7% vs 15.5%)、全因住院率(43.8% vs. 44.9%)和死亡率(9.9% vs. 10.1%)均相似。

研究者还对11,619例单腔ICD植入患者和相同数量的双腔ICD植入患者进行了倾向性配对分析。结果显示，单腔ICD植入患者的严重并发症发生率(3.5%)同样低于双腔ICD植入患者(4.7%)，需要系统修正的装置功能故障也表现出最大绝对差异。此外，研究者称，两组患者1年全因住院率和死亡率未见差异(JAMA 2013;309:2025-34)。对不同年龄、性别或肾脏功能正常或不全亚组患者的进一步分析结果与上述结果一致。

Peterson博士及其同事说，这些发现表明与单腔ICD相比，双腔ICD似乎没有提供任何额外临床益处，至少在死亡率或再住院率方面未见优势。这一研究也存在着局限性，如由于缺少上述因素的相关资料，研究未能对患者生活质量或房颤发生率等其他重要结局进行分析。

这项研究由美国医疗保健研究与质量局和美国心脏病学会基金会全国心血管数据注册予以支持。Peterson博士称无经济利益冲突，她的一位同事报告收受了波士顿科学公司的基金资助。

Association of Single- vs Dual-Chamber ICDs With Mortality, Readmissions, and Complications Among Patients Receiving an ICD for Primary Prevention
Importance 
Randomized trials of implantable cardioverter-defibrillators (ICDs) for primary prevention predominantly used single-chamber devices. In clinical practice, patients often receive dual-chamber ICDs, even without clear indications for pacing. The outcomes of dual- vs single-chamber devices are uncertain.
Objective 
To compare outcomes of single- and dual-chamber ICDs for primary prevention of sudden cardiac death.
Design, Setting, and Participants 
Retrospective cohort study of admissions in the National Cardiovascular Data Registry's (NCDR) ICD registry from 2006-2009 that could be linked to Centers for Medicare & Medicaid Services fee-for-service Medicare claims data. Patients were included if they received an ICD for primary prevention and did not have a documented indication for pacing.
Main Outcomes and Measures 
Adjusted risks of 1-year mortality, all-cause readmission, heart failure readmission, and device-related complications within 90 days were estimated with propensity-score matching based on patient, clinician, and hospital factors.
Results 
Among 32 034 patients, 12 246 (38%) received a single-chamber device and 19 788 (62%) received a dual-chamber device. In a propensity-matched cohort, rates of complications were lower for single-chamber devices (3.51% vs 4.72%; P < .001; risk difference, −1.20 [95% CI, −1.72 to −0.69]), but device type was not significantly associated with 1-year mortality (unadjusted rate, 9.85% vs 9.77%; hazard ratio [HR], 0.99 [95% CI, 0.91 to 1.07]; P = .79), 1-year all-cause hospitalization (unadjusted rate, 43.86% vs 44.83%; HR, 1.00 [95% CI, 0.97-1.04]; P = .82), or hospitalization for heart failure (unadjusted rate, 14.73% vs 15.38%; HR, 1.05 [95% CI, 0.99-1.12]; P = .19).
Conclusions and Relevance 
Among patients receiving an ICD for primary prevention without indications for pacing, the use of a dual-chamber device compared with a single-chamber device was associated with a higher risk of device-related complications and similar 1-year mortality and hospitalization outcomes. Reasons for preferentially using dual-chamber ICDs in this setting remains unclear.