波士顿(EGMN)——心律学会(HRS)年会上公布的一项回顾性研究显示，与其他生产商生产的导线相比，Riata植入型心律转复除颤器(ICD)导线发生故障的几率明显更高。

　　这项研究在美国7个中心进行，由明尼阿波利斯心脏研究所的Raed Abdelhadi博士及其同事开展。所有入组患者的年龄均大于18岁。研究者对774例植入8-French Riata导线的患者(平均随访4.2年)和307例植入7-French Riata ST导线(平均随访3.3年)的患者的全因故障和电子故障进行了探讨。对照组是来自一项探讨Sprint Fidelis 导线使用寿命和故障危险因素的3中心研究中的Quattro Secure ICD导线(Medtronic)组(Circulation 2011;123:358-63)。排除有机硅聚氨酯共聚物绝缘的ICD导线(RIATA ST Optim和Durata导线)。

　　导线故障定义为“导致置换的阻抗异常、表现为非生理信号的电子噪声、需要植入导线的起搏阈值增加或R波幅降低、由于明显的导线异常而无法获得有效治疗效果、或荧光镜透视检查或X线检查清楚可见导线外露……，即使导线功能正常且电子环路完整。”功能异常(如，导线电极功能完整但传出阻滞和生理感知过度)和导线脱位(除非是由固定机制不佳引起)均不属于故障。故障的征象包括导致不当治疗的噪音、导致失夺获和晕厥并需要置换导线的阈值增加的情况、异常起搏阻抗、异常高压阻抗、需要置换导线的R值降低、以及除颤阈值测试失败伴异常高压阻抗、需要置换导线。

　　末次随访时，在1,081例植入Riata和Riata ST导线(St. Jude Medical)的患者中，712例(66%)可正常活动且功能正常。在取出导线的302例(28%)患者中，266例的原因为死亡，10例为移植，5例为穿孔，4例为感染，17例为其他原因。Riata导线组的故障发生率为1.93%，显著高于对照Quattro Secure导线组的0.43% (P<0.0001)。Riata ST导线组的故障发生率为0.50%，与对照组无显著差异。

　　该研究对10%的导线进行检查，查看有无导线外露的情况，结果发现27例(25%)存在此类情况。在该组中，7例(26%)导线发生故障。

　　有65例Riata导线故障和5例Riata ST导线故障，全因故障发生率为6.2%。在该组中，47例故障的原因为电极故障，其中上述7例故障由导线外露引起。另外20例导线虽然功能正常但导线外露，符合故障定义。相比之下，在1,668例植入Quattro Secure导线的患者中，23例(1.37%)导线发生故障。

　　单因素分析显示，年龄、性别、ICD植入的一级或二级指征、射血分数、心脏病类型以及导线植入位置均与导线故障风险无显著关系。对Riata ST导线进行分析也获得相同结果。

　　该研究的局限性包括：使用回顾性设计、仅检查10%的导线是否存在导线外露的情况、以及Riata ST组的随访时间比另外2组短。此外，大多数导线故障未被返回产品分析所证实。

　　Abdelhadi博士声明无经济利益冲突。

原文阅读：

BY NEIL OSTERWEIL

Elsevier Global Medical News

　　Breaking News

　　BOSTON (EGMN) – An independent investigation by seven U.S. centers has shown that recently recalled Riata implantable cardioverter defibrillator leads are significantly more prone to failure than are leads made by a different manufacturer.

　　A retrospective study of all patients older than 18 years who received ICDs with either Riata or Riata ST leads (St. Jude Medical) showed a failure rate of 1.93% per patient-year for Riata leads, significantly more than the rate of 0.43% for the comparator lead, Quattro Secure (Medtronic) (P less than .0001). The failure rate for Riata ST leads was 0.50%, a nonsignificant difference, reported Dr. Raed Abdelhadi of the Minneapolis Heart Institute.

　　The Riata and Riata ST ICD leads are prone to inside-out and outside-in silicone insulation defects, which can cause lead malfunction and externalization (breach of the outer insulation, visible outside the lead body) of the conductor cables, but until this study, there were no independent, multicenter investigations into the rate of lead failure, failure signs, or clinical sequelae, he said.

　　“Without such data, it is not possible to design evidence-based management strategies or to advise Riata patients of their risks,” he said at the annual meeting of the Heart Rhythm Society.

　　Investigators at the seven centers looked at all-cause failures and electrical malfunctions in 774 patients who received an 8-French Riata lead (mean follow-up, 4.2 years), and 307 patients who received a 7-French Riata ST lead (mean follow-up, 3.3 years). ICD leads with silicone-polyurethane copolymer insulation (RIATA ST Optim and Durata leads) were excluded.

　　For comparison, they obtained data on the Quattro Secure ICD leads from a three-center study of the longevity and risk factors for failure of Sprint Fidelis leads (Circulation 2011;123:358-63).

　　The investigators defined lead failure as either “abnormal impedance leading to replacement, electrical noise manifested by nonphysiologic signals, increase in pacing threshold or decline in R-wave amplitude necessitating lead placement, inability to provide effective therapy due to apparent lead abnormality, or externalized conductor, clearly demonstrated on fluoroscopy or x-ray ... even if the lead was functioning normally and electrically intact.”

　　Neither functional abnormalities (for example, exit block and physiologic oversensing in the presence of an electrically intact lead) nor lead displacement (unless caused by a bad fixation mechanism) were considered to be failures.

　　Of the 1,081 Riata and Riata ST leads implanted, 712 (66%) were active and functioning normally at last follow-up. Of the 302 (28%) removals from service, 266 were owing to death, 10 to transplant, 5 to perforation, 4 to infection, and 17 to other causes.

　　In all, 10% of leads in the study were examined for externalized conductors, and 27 (25%) were found to have them. Of this group, seven (26%) leads were malfunctioning.

　　There were 65 Riata failures and 5 Riata ST failures, for a 6.2% incidence of all-cause failures. Of this group, 47 failures were due to electrical malfunctions, including seven from the externalized conductors contributing to the malfunction, as noted before. An additional 20 leads had externalized conductors with normal function, but met the study definition of failure.

　　In contrast, there were 23 lead failures among 1,668 patients with Quattro Secure leads (1.37%).

　　In univariate analysis, neither age, gender, primary or secondary indication for ICD implantation, ejection fraction, type of cardiac disease, nor lead placement location were significantly associated with risk for lead failure. The same was true when the Riata ST leads were subtracted from the equation.

　　Signs of failure included noise resulting in inappropriate therapy, elevated thresholds requiring lead replacement resulting in loss of capture and syncope, abnormal pacing impedance, abnormal high-voltage impedance, decline in R value requiring lead replacement, and failed defibrillation threshold testing with abnormal high-voltage impedance, requiring lead replacement.

　　Dr. Abdelhadi noted that the study was limited by its retrospective design, the fact that only 10% of leads were examined for externalized conductors, and the relatively short follow-up in the Riata ST group compared with the other two groups. In addition, most lead failures were not confirmed by returned-product analysis.

　　The study confirms what was already known and what many meeting attendees expected to hear, commented Dr. Hugh Calkins, professor of cardiology at the Johns Hopkins Heart and Vascular Institute, Baltimore, and vice president of the Heart Rhythm Society, in an interview.

　　“The bottom line is that it’s all about the patients, and how we take care of them, advise them, and whether we explant the leads. The whole international heart rhythm community is focused on this question and what to do so that there aren’t deaths that result from noise, that there aren’t deaths from unnecessary lead extractions,” he said. Dr. Calkins was not involved in the study, but he moderated a media briefing where Dr. Abdelhadi presented the data.

　　Dr. Abdelhadi and Dr. Calkins reported having no current conflicts of interest to disclose.

（责任编辑：颜子力）