Long-Term Evaluation of Biotronik Linox and Linox(smart) Implantable Cardioverter Defibrillator Leads

Performance of an implantable cardioverter-defibrillator lead family

BACKGROUND

Lead failure is the major limitation in implantable cardioverter-defibrillator (ICD) therapy. Long-term follow-up data for Biotronik Linox ICD leads are limited. Therefore, we analyzed the performance of all these leads implanted at our institution.

MATERIALS AND METHODS

All Linox and Linox Smart ICD leads implanted between 2006 and 2015 were identified. Lead failure was defined as electrical dysfunction (oversensing, abnormal impedance, exit block). Lead survival was described, according to Kaplan-Meier. Associations between lead failure and specific variables were examined. p < .05 was considered significant.

RESULTS

We included 417 ICD leads. The median follow-up time for Linox (n = 205) was 81 months and for Linox Smart (n = 212) 75 months. During that follow-up time, 30 Linox (14.6%) and 16 Linox Smart leads (7.6%) showed a malfunction. The 5-year lead survival probability was 97.4% for Linox and 95.2% for Linox Smart (log-rank test, p = .19). The 6- and 8-year lead survival probability for Linox was 93.6% and 84.6%, and for Linox Smart 93% and 91.9%. The only factor significantly associated with lead failure was younger patient age at implantation (hazard ratio/year: 0.97, 95% CI: 0.94-0.99, p = .002).

CONCLUSION

This relatively large study with a long follow-up period highlights a relevant failure rate of Biotronik Linox leads. The performance of Linox versus Linox Smart ICD leads was comparable. Although we show an acceptable 5-year lead survival probability, we observed a marked drop after just 1 more year of follow-up. In an era of improving heart failure survival probability, a prolonged follow-up of ICD leads is increasingly clinically relevant.

Implantable cardioverter defibrillator lead performance: A systematic review and individual patient data Meta-analysis

BACKGROUND

Reliable post-approval surveillance of implantable cardioverter-defibrillator (ICD) lead performance remains a challenge. In the past, two ICD leads were recalled due to a high frequency of failures. In this meta-analysis, we sought to provide a combined estimate of failure-free rate for ICD leads by reconstructing individual patient data from published Kaplan-Meier (KM) curves and to investigate whether estimates could be influenced by the characteristics of the study.

METHODS

Observational studies assessing failure-free estimates of transvenous ICD leads with KM method, were identified through a systematic search up to November 2021.

RESULTS

Forty-four studies were eligible that included 41,870 (63.1%) non-recalled leads and 24,493 (36.9%) recalled leads. The 8-year cumulative failure-free rate was 94.1% (CI, 93.6% - 94.6%) for contemporary non-recalled leads and 81.2% (80.3% - 82.0%) for recalled leads (hazard ratio [HR], 3.15 [2.85-3.47], p < 0.001). Failure-free rate was lower in single-center studies in both the non-recalled (HR, 0.28 [0.15-0.51], p < 0.001) and recalled (HR, 0.54 [0.33-0.88], p = 0.014) group compared with multicenter studies. Similarly, estimates were significantly lower in small (i.e. extracted KM curve with <312 leads) versus large studies (HR non-recalled group, 0.54 [CI, 0.33-0.89], p = 0.015; HR recalled group, 0.62 [CI, 0.43-0.89], p = 0.009).

CONCLUSIONS

In this meta-analysis including >66,000 leads, we provide pooled survival curves that may play a role in generating evidence-based standards for assessing clinically acceptable failure rates for ICD leads. Lead performance was underestimated with single-center and small-sized studies; multicenter studies remain the main tool to reliably conduct post-market surveillance of ICD leads.

Long-term longevity and clinical outcomes of Linox S/SD implantable cardioverter-defibrillator leads: a single-center experience

PURPOSE

Since the introduction of the Biotronik Linox S/SD leads in 2006, there have been multiple reports of premature lead failure. The purpose of this study was to investigate the longevity of the Linox S/SD leads and to identify the possible predictors of lead failure in a single tertiary implant center.

METHODS

We retrospectively reviewed patients who underwent implantation of Linox S/SD leads or Sorin Vigila 1CR/2CR leads (the same Linox S/SD leads marketed by Sorin) at our center. The cumulative lead survival was estimated using the Kaplan-Meier curve, and variables associated with lead failure were assessed by Cox proportional hazard model.

RESULTS

A total of 187 patients (154 (82%) male) underwent Linox S/SD or Vigila 1CR/2CR implantation between 2007 and 2013. During follow-up with a median time of 75 months, nine lead failures were identified (4.8%). The mean and median times from lead implantation to lead failure were 70.7 ± 21 months and 64 (45-111) months, respectively. The cumulative survival probability for the Linox S/SD at 5 years was 97.1% and at 12 years was 90.3%. Non-physiological high-rate sensing was the most common type of lead failure in patients. In two-thirds of these patients, this led to inappropriate shock. We did not find any significant relationships between patients' clinical and procedural characteristics and lead failure.

CONCLUSIONS

At our center, the 5-year lead survival of the Linox S/SD has been better than reports from other centers. The majority of lead failures presented as non-physiological high-rate sensing with subsequent inappropriate therapy.

Comparison of the performance of implantable cardioverter-defibrillator leads among manufacturers

BACKGROUND

Leads are often considered the weakest link in implantable cardioverter-defibrillator (ICD) systems, and lead dysfunction is a major concern for ICD recipients. The aim of this study was to compare the lead performance from three different manufacturers.

METHODS

We retrospectively reviewed consecutive patients who underwent ICD system implantation at Chiba University Hospital, Japan, between March 2008 and September 2017. The following leads were implanted in our center: Durata (St. Jude Medical, St. Paul, MN, USA, now Abbott) (n = 105), Linox and Linox^Smart (Biotronik, Berlin, Germany) (n = 66), and Sprint Quattro (Medtronic, Minneapolis, MN, USA) (n = 126).

RESULTS

A total of 297 ICD leads were analyzed. Failure rates for Durata, Linox/Linox^Smart, and Sprint Quattro were 0.20%/patient year, 0.95%/patient year, and 1.84%/patient year, respectively, during a mean follow-up of 4.8, 6.4, and 3.0 years, respectively. The cumulative ICD lead survival probability was 98.9%, 100%, and 87.5%, after 5 years, respectively. The survival probability over the entire follow-up time as measured by the log-rank test was lower for Sprint Quattro leads than for either Durata (p = 0.011) or Linox/Linox^Smart (p = 0.028). The difference between Durata and Linox/Linox^Smart was not significant (p = 0.393).

CONCLUSIONS

In this single-center retrospective study, the performance of Sprint Quattro was lower than the performance of Linox/Linox^Smart and Durata leads. Large-scale, multi-center studies or manufacturer-independent registries may be necessary to confirm or reject self-reported survival probabilities from manufacturers' product performance reports.

Important Parameters for Implantable Cardioverter Defibrillator Selection

The efficacy of implantable cardioverter defibrillators in reducing the risk of sudden cardiac death has been well established by several clinical trials. Several factors relating to device characteristics, patient attributes, and comorbidities should be considered when selecting the appropriate implantable cardioverter defibrillators for each patient. This review examines some of these issues.

Comparison of lead failure manifestation of Biotronik Linox with St. Jude Medical Riata and Medtronic Sprint Fidelis lead

PURPOSE

To compare lead failure manifestation and lead performance of the Biotronik Linox/Sorin Vigila defibrillator lead (Linox group) with the St. Jude Medical Riata/Riata ST (Riata group) and Medtronic Sprint Fidelis defibrillator leads (Fidelis group).

METHODS

We assessed the performance of all aforementioned leads implanted at our center and investigated the manifestation of lead failures.

RESULTS

Of 93 Linox, 86 Riata, and 81 Fidelis leads implanted at our center, 11 (12%), 22 (26%), and 25 (31%) leads failed during a median follow-up of 46, 61, and 84 months, respectively. Inappropriate shocks were delivered in 64% (Linox), 5% (Riata), and 32% (Fidelis) of lead failures; a device alert was noted in none (Linox), 5% (Riata), and 52% (Fidelis); and lead failure was a coincidental finding in 36% (Linox), 91% (Riata), and 16% (Fidelis) of cases (p < 0.001). Non-physiological high rate signals were observed in 73% (Linox), 27% (Riata), and 80% (Fidelis) of lead failures (p = 0.001) and damaged lead integrity was found in 36% (Linox), 73% (Riata), and 24% (Fidelis) of cases (p = 0.064). Lead survival at 5 years was 88%, 92%, and 71% for Linox, Riata, and Fidelis group, respectively.

CONCLUSIONS

The most frequent clinical manifestation of lead failure was inappropriate shocks for Linox, coincidental finding for Riata and device alert for Fidelis leads. Non-physiological high rate signals were frequently observed in Linox and Fidelis lead failures whereas in Riata lead failures, a damaged lead integrity was the predominant finding.

Analysis of early failure of Biotronik Linox Smart implantable cardioverter-defibrillator leads: A comparative study of three defibrillator leads

BACKGROUND AND OBJECTIVES

Early failure of Biotronik Linox and Linox Smart leads (Biotronik, Berlin, Germany) has been reported in numerous recent publications. The aim of this study was to assess the performance of this lead compared with that of two other contemporary leads.

METHODS

We conducted an ambispective study of all consecutive first implantations of defibrillator leads carried out in our center: Endotak (model 148, 158, Boston Scientific, Marlborough, MA, USA) (n = 173), Sprint Quattro (model 6644, 6947, Medtronic, Dublin, Ireland) (n = 145), and Linox Smart (Biotronik, model SD 65/16) (n = 120).

RESULTS

During a median follow-up of 4.6 ± 2.1 years, failure occurred in nine Linox Smart (7.5%), one Endotak Reliance (0.6%), and no Sprint Quattro leads. The survival probability of the Linox Smart group was significantly lower than that of the Endotak and Sprint Quattro groups measured by the log-rank test (Linox vs Endotak; P < 0.001 and Linox vs Sprint Quattro; P < 0.001). Nonphysiological signals not due to external interference were observed in all Linox Smart leads, with normal parameters and without visible anomalies on chest x-ray.

CONCLUSIONS

In this single-center experience, the survival rate of Linox Smart leads was 88% at 5 years of follow-up, which was significantly lower than that of the other leads. Comprehensive vigilance of Linox Smart leads, including home monitoring, may be advisable to facilitate early detection of lead failure and avoid inappropriate shocks.

Prospective Assessment of Linox Implantable Cardioverter Defibrillator Leads for Structural or Electrical Abnormalities

INTRODUCTION

Insulation failure leading to conductor externalization (CE) of a Linox (Biotronik, Berlin, Germany) implantable cardioverter defibrillator (ICD) lead has recently been reported. The aim of this study was to assess prospectively all Linox family ICD leads implanted at our center for evidence of CE or an electrical abnormality.

METHODS

All patients with a Linox family ICD lead implanted at our center, between November 2007 and March 2015, were identified and all living patients were invited to attend for fluoroscopic screening and electrical assessment of the lead.

RESULTS

A total of 183 patients had a Linox family ICD lead implanted at our center. Of these, 5 patients (2.7%) had the lead extracted because of electrical failure and 2 of these leads had evidence of CE. Out of 158 living patients with a Linox family ICD lead, 111 patients attended for screening (mean age 63.1 years, 22.5% female). In this group of patients, no cases of CE or electrical abnormalities of the lead were identified.

CONCLUSION

In this study evaluating 183 patients with a Linox family ICD lead implanted at a single center, 5 leads (2.7%) were explanted because of electrical failure and 2 of these leads had evidence of CE. Prospective fluoroscopic assessment of 111 Linox family ICD leads, with a mean dwell time of 31.5 months, revealed no further cases of CE.

Comparative study of the failure rates among 3 implantable defibrillator leads

BACKGROUND

After the introduction of the Biotronik Linox S/SD high-voltage lead, several cases of early failure have been observed.

OBJECTIVE

The purpose of this article was to assess the performance of the Linox S/SD lead in comparison to 2 other contemporary leads.

METHODS

We used the prospective Erasmus MC ICD registry to identify all implanted Linox S/SD (n = 408), Durata (St. Jude Medical, model 7122) (n = 340), and Endotak Reliance (Boston Scientific, models 0155, 0138, and 0158) (n = 343) leads. Lead failure was defined by low- or high-voltage impedance, failure to capture, sense or defibrillate, or the presence of nonphysiological signals not due to external interference.

RESULTS

During a median follow-up of 5.1 years, 24 Linox (5.9%), 5 Endotak (1.5%), and 5 Durata (1.5%) leads failed. At 5-year follow-up, the cumulative failure rate of Linox leads (6.4%) was higher than that of Endotak (0.4%; P < .0001) and Durata (2.0%; P = .003) leads. The incidence rate was higher in Linox leads (1.3 per 100 patient-years) than in Endotak and Durata leads (0.2 and 0.3 per 100 patient-years, respectively; P < .001). A log-log analysis of the cumulative hazard for Linox leads functioning at 3-year follow-up revealed a stable failure rate of 3% per year. The majority of failures consisted of noise (62.5%) and abnormal impedance (33.3%).

CONCLUSION

This study demonstrates a higher failure rate of Linox S/SD high-voltage leads compared to contemporary leads. Although the mechanism of lead failure is unclear, the majority presents with abnormal electrical parameters. Comprehensive monitoring of Linox S/SD high-voltage leads includes remote monitoring to facilitate early detection of lead failure.