Cable externalization and electrical failure of the Riata family of implantable cardioverter-defibrillator leads: A systematic review and meta-analysis

Poorer outcomes associated with more invasive lead management strategies for Abbott Riata® leads: a large, multicenter experience

BACKGROUND

Over 100,000 Abbott Riata® were implanted in the United States before they were recalled in 2010. There are still a significant number of Abbott Riata® leads in use, and it is unclear how these leads should be managed at the time of generator change or lead malfunction. Although data comparing both Sprint Fidelis® and Abbott Riata® leads in this setting is available, there are no multicenter comparative studies of outcomes for various lead management strategies, including lead extraction (LE), lead abandonment/revision (LA), and generator change (GC) only at the time of device at elective replacement interval (ERI) for Abbott Riata® leads.

METHODS

A retrospective, multicenter study was undertaken to compare short-term outcomes (major complications-MC, death, extended or re-hospitalizations within 60 days-RH, lead malfunction-LM) and total outcomes (short-term outcomes & lead malfunction during follow-up) of patients with Riata® leads undergoing LE, LA, or GC.

RESULTS

152 patients (65 ± 13 years, 68% male) were followed for a mean 33 ± 30 months following intervention. Out of 166 procedures, 13 patients underwent LE, 16 patients underwent LA, and 137 patients underwent GC. There was 1 major complication in each group, yielding an event rate of 7.7% for LE, 6.3% for LA, and 0.7% for GC cohorts. There were significantly more short-term and total adverse outcomes in the group of patients getting LE and LA versus GC only (38.5% & 31.3% vs 7.3%, P < 0.001). Total Riata® lead dwell time follow-up was 17,067 months. A total of 3 Riata® lead malfunctions were noted during long-term follow-up. Inappropriate shocks were similar between LE 7.7% (1/13), LA 6.3% (1/16). and GC 11.0% (4/136); P = 0.57.

CONCLUSIONS

There were more short-term and total adverse outcomes in more invasive management strategies (LE and LA) versus GC alone. The failure rate of Riata® leads was substantially lower compared to previous reports. Therefore, we recommend only performing battery exchange when a device with an active Riata® lead is at ERI, unless there is malfunction of the Riata® lead noted on testing.

Rationale and design of the Lead Evaluation for Defibrillation and Reliability study: Safety and efficacy of a novel ICD lead design

BACKGROUND

Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small-diameter, lumenless, catheter-delivered, defibrillator lead was developed with the aim to improve long-term reliability.

METHODS AND RESULTS

The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi-center, single-arm, Bayesian, adaptive design, pre-market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre-hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients may be participating for a minimum of 18 months to approximately 3 years. Fracture-free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in-vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow-up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled.

CONCLUSION

The LEADR Clinical Study was designed to efficiently provide evidence for short- and long-term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach.

Subcutaneous and Transvenous ICDs: an Update on Contemporary Questions and Controversies

PURPOSE OF REVIEW

While the subcutaneous (S-) implantable cardioverter-defibrillator (ICDs) is an alternative to the transvenous (TV-) ICD in many patients, optimal use remains unclear. In this review, we summarize recent clinically relevant data on sensing algorithms, inappropriate shocks, defibrillation testing, and battery and electrode failures.

RECENT FINDINGS

Changes in sensing algorithms and S-ICD programming have significantly decreased inappropriate shock rates. Avoiding fat below the S-ICD coil and can is key for reducing the defibrillation threshold. While S-ICD battery and electrode failures have resulted in recalls, system components remain commercially available since failure rates are low and no other similar devices are available. The S-ICD is a good alternative to the TV-ICD for many patients, and particularly in light of recently developed device algorithms and improvements in implant technique. Future research will need to better understand: the impact of S-ICD electrode and battery failures and the potential for integrating leadless pacing into a modular S-ICD platform.

Externalized Conductors and Electrical Dysfunction in Transvenous Ventricular Leads: Results of the Cardiac Lead Assessment Study

Background

The Cardiac Lead Assessment Study (CLAS) was a large prospective, multicenter, international postmarket surveillance study conducted at 45 sites.

Objective

The purpose of CLAS was to examine the prevalence and incidence of externalized conductors and electrical dysfunction in subjects with selected St. Jude Medical defibrillator and left ventricular leads.

Methods

Cinefluoroscopy was used to determine the presence of externalized conductors at enrollment and at 12-, 24-, and 36-month follow-up visits. Lead electrical measurements were collected systematically.

Results

The study enrolled 2216 subjects with a total of 2847 study leads. The prevalence of externalized conductors through 36 months for Riata leads was 30.9%, Riata ST leads 12.6%, Durata leads 0.5%, and QuickSite/QuickFlex leads 4.7%. The prevalence of electrical dysfunction through 36 months for Riata was 4.0%, Riata ST 3.3%, Durata 2.4%, and QuickSite/QuickFlex 0.3%. In Riata and Riata ST leads with externalized conductors, there was a low risk of electrical dysfunction. None of the Durata or QuickSite/QuickFlex leads with externalized conductors developed electrical dysfunction. There was no evidence of an electrical short in a high-voltage shocking circuit leading to failed shock.

Conclusion

A high prevalence of externalized conductors was found in Riata and Riata ST defibrillator leads, with a higher risk of externalization for 8F Riata leads than for 7F Riata ST leads. The 98% reduction in prevalence of externalized conductors in Durata leads compared to Riata/Riata ST leads confirms that the design improvements culminating in Durata leads significantly improved abrasion resistance and durability.

Prospective long-term follow-up of silicone-polyurethane–insulated implantable cardioverter-defibrillator leads

Background

Objective

Methods

Results

Conclusion

Comparative outcomes of Riata and Fidelis lead management strategies: Results from the NCDR-ICD Registry

BACKGROUND

The Medtronic Sprint Fidelis® and Abbott Riata®/Riata ST® leads are at risk of failure and are subject to FDA recall. Comparative risks of various lead management strategies during elective generator change in a multi-center population are unknown. We aim to describe patients with functional, recalled ICD leads undergoing elective generator replacement and report outcomes according to lead management strategies.

METHODS

Using data from the NCDR ICD Registry, patients with a functioning Riata® or Fidelis® lead undergoing generator replacement are described according to lead management: reuse, abandon/replace, and extract/replace. Adjusted rates of death and pre-discharge complications are reported.

RESULTS

There were 13,144 generator replacement procedures involving a functioning, non-infected Riata® or Fidelis® lead (extraction n = 414, abandonment n = 427). Extraction patients were younger (mean 58 vs. 67 years) with fewer comorbidities than the reuse group. Maximum lead dwell time was similar between groups with average 94, 90, and 99 months in the extraction, abandonment, and reuse groups, respectively. In-hospital complications or mortality were more common in the extraction group (10.14%, 4.35%) compared with abandonment (1.64%, 0.47%) and reuse (0.22%, 0.07%). Compared with reuse, the adjusted odds of death or pre-discharge complication were significantly higher in the extraction group (OR 7.77 95% CI 2.42-24.95, p < .001) but not the abandonment group (OR 1.70 95% CI 0.52-5.61, p = .38).

CONCLUSIONS

In this real-world population, extraction of functional recalled ICD leads was associated with significant risk of in-hospital mortality and complications. Additional work is needed to clarify whether longer term outcomes balance these peri-procedural risks.

In vitro modeling accurately predicts cardiac lead fracture at 10 years

BACKGROUND

Development of a cardiac lead fracture model has the potential to differentiate well-performing lead designs from poor performing ones and could aid in future lead development.

OBJECTIVE

The purpose of this study was to demonstrate a predictive model for lead fracture and validate the results generated by the model by comparing them to observed 10-year implantable cardioverter-defibrillator lead fracture-free survival.

METHODS

The model presented here uses a combination of in vivo patient data, in vitro conductor fatigue test data, and statistical simulation to predict the fracture-free survival of cardiac leads. The model was validated by comparing the results to human clinical performance data from the Medtronic Sprint Fidelis (Minneapolis, MN) models 6931 (single coil, active fixation) and 6949 (dual coil, active fixation), as well as the Quattro model 6947 (dual coil, active fixation).

RESULTS

Median patient age in the single coil Fidelis 6931 population (64 years) was less than in the dual coil Fidelis 6949 and Quattro populations (68 years). Modeled and observed fracture-free survival for Quattro (>97%) was superior to that for Fidelis (<94%). The modeled survival agreed with the observed fracture-free survival data. The average model error was 0.3% (SD 1.2%).

CONCLUSION

This model for cardiac lead fracture-free survival using in vivo lead bending measurements and in vitro bench testing can be used to predict lead performance as observed by alignment with field survival data.

Endovascular Neuromodulation: Safety Profile and Future Directions

Endovascular neuromodulation is an emerging technology that represents a synthesis between interventional neurology and neural engineering. The prototypical endovascular neural interface is the Stentrode^TM, a stent-electrode array which can be implanted into the superior sagittal sinus via percutaneous catheter venography, and transmits signals through a transvenous lead to a receiver located subcutaneously in the chest. Whilst the Stentrode^TM has been conceptually validated in ovine models, questions remain about the long term viability and safety of this device in human recipients. Although technical precedence for venous sinus stenting already exists in the setting of idiopathic intracranial hypertension, long term implantation of a lead within the intracranial veins has never been previously achieved. Contrastingly, transvenous leads have been successfully employed for decades in the setting of implantable cardiac pacemakers and defibrillators. In the current absence of human data on the Stentrode^TM, the literature on these structurally comparable devices provides valuable lessons that can be translated to the setting of endovascular neuromodulation. This review will explore this literature in order to understand the potential risks of the Stentrode^TM and define avenues where further research and development are necessary in order to optimize this device for human application.

Complications involving the subcutaneous implantable cardioverter-defibrillator: Lessons learned from MAUDE

BACKGROUND

Reports on the subcutaneous implantable cardioverter-defibrillator (S-ICD) cumulatively demonstrate a low rate of complications, but clinical experience with this technology is limited compared with transvenous devices.

OBJECTIVE

The purpose of this study was to describe and analyze S-ICD complications reported to the Food and Drug Administration's Manufacturer and User Facility Device Experience database.

METHODS

We reviewed all S-ICD events reported to the Manufacturer and User Facility Device Experience submitted over 24 months (from February 2016 through February 2018) through a prospective and standardized approach at a time when an estimated 15,000 S-ICDs were in service.

RESULTS

After removing duplicate entries and nonclinical events (n = 493), 1604 events remained. A total of 542 instances of infection were reported with system removal in 414/542 (77.5%). Inappropriate shocks occurred in 550 patients, and 382 (69%) were attributed to oversensing; in response, 254 (56%), 147 (33%), and 80 (18%) patients underwent system reprogramming, removal, or revision, respectively. There were 15 deaths, and causes included defibrillation failure during follow-up (n = 2), ventricular fibrillation induced by the device (n = 4), device-device interaction resulting in undersensing (n = 1), procedure-related complications (n = 4), and uncertain etiology (n = 4). There were 137 reports of system migration, and in 57 (42%) of these, there were associated inappropriate shocks. System migration events were managed with a combination of system revision (69 [51%]), reprogramming (25 [18%]), and system removal (44 [32%]).

CONCLUSION

Several S-ICD complications have been reported that appear to be related to the ICD's design and function over time. A better understanding of these complications may help inform patient selection, implant technique, and postimplantation management.

The role of transvenous lead extraction in the management of redundant or malfunctioning pacemaker and defibrillator leads post ELECTRa

Cardiac implantable electronic devices implantation rates have increased over the past decade due to broader indications and an ageing population. Similarly, device and lead complications have also risen. The management of pacemaker/defibrillator leads that are no longer required (redundant) or malfunctioning, can be contentious. There is a need to balance the risk of transvenous lead extraction (TLE) against those of lead abandonment. The recently published European Lead Extraction ConTRolled Registry (ELECTRa) study provides contemporary outcomes for TLE across Europe with important implications for the management of redundant and/or malfunctioning leads. This review article discusses the potential complications for each interventional approach when managing redundant or malfunctioning pacemaker leads.

Failure-free survival of the Riata implantable cardioverter-defibrillator lead after a very long-term follow-up

Aims

Riata^® implantable cardioverter-defibrillator (ICD) leads from St. Jude Medical are prone to malfunction. This study aimed to describe the rate of this lead's malfunction in a very long-term follow-up.

Methods

This single-centre observational study included 50 patients who received a Riata 7Fr dual-coil lead between 2003 and 2008. Follow-up was conducted both in person and remotely, and analysed at 8-month intervals. We evaluated the rates of cable externalization (CE), electrical failure (EF), and the interaction of these two complications. Structural lead failure was defined as radiographic CE. Oversensing of non-cardiac signal or sudden changes in impedance, sensing, or pacing thresholds constituted EF.

Results

During a mean follow-up of 10.2 ± 2.9 years, 16 patients (32%) died. We observed lead malfunction in 13 patients (26%): three (23%) due to CE, six (46%) to EF and four (31%) to both complications. Of the malfunctioning leads, 77% failed after seven years of follow-up. The incidence rate (IR) of overall malfunction per 100 patients per year was 0.9 during the first seven years post-implantation, increased to 7.0 after the 7th year and more than doubled (to 16.7) after 10 years. Beyond seven years post-implantation, IR per 100 patient-years increased in both EF and CE (from 0.6 to 5.6 vs. 0.3 to 4.2, respectively). Presence of CE was associated with a 4-fold increase in the proportion of EF.

Conclusion

The incidence of Riata ICD lead malfunction, both for EF and CE, increased dramatically after seven years and then more than doubled after 10 years post-implantation.

Long-term performance of a pacing lead family: A single-center experience

BACKGROUND

The performance of Abbott/St. Jude Medical (Sylmar CA) Tendril pacing leads has not been well characterized.

OBJECTIVE

We sought to assess the performance of Tendril leads as compared with that of different pacing leads.

METHODS

We retrospectively identified patients implanted with the following leads: Tendril leads 1888 TC, 2088 TC, and 1688 TC, Medtronic (Fridely, MN) 4076 CapSureFix Novus, and Boston Scientific (Natick, MA) FINELINE II Sterox Pacing EZ leads (models 4469, 4470, and 4471). The primary end point was the incidence of lead malfunction assessed by Kaplan-Meier analysis.

RESULTS

During the study period, 9782 leads were implanted, including 8512 Tendril leads, 731 Medtronic 4076 CapSureFix Novus leads, and 539 FINELINE II leads. A total of 540 leads (5.5%) malfunctioned during a mean follow-up of 3.6 ± 2.9 years. Lead malfunction manifested predominantly as noise and/or low impedance (95%). Lead malfunction rates were significantly higher at 5 years for Tendril vs non-Tendril leads (7.0% vs 2.1%; P < .001). The highest rate of failure at 5 years was seen in the Tendril 1888 TC leads (9.9%), followed by Tendril 1688 (5.7%) and Tendril 2088 (5.2%) leads. In contrast, malfunction rates were significantly lower for the Medtronic 4076 (2.6%) and FINELINE II (1.7%) leads. During follow-up to 10 years, the incidence of lead malfunction for Optim-insulated Tendril leads (models 1888 TC and 2088 TC) was significantly higher than that for the non-Optim-insulated Tendril 1688 TC lead (24.5% vs 7.1%) (P = .008).

CONCLUSION

Tendril leads appear to have a higher rate of malfunction than do comparator leads. Optim insulation may partly explain the higher failure rate.

Impact of ICD lead on the system durability, predictors of long-term survival following ICD system extraction

BACKGROUND

Implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy defibrillator (CRT-D) systems are considered as having higher risk of complication and shorter durability but reasons of this multifactorial phenomenon remain unclear. We aimed to analyze this problem in population of patients with ICD leads referred for lead extraction (TLE).

METHODS

We have compared TLE indications, procedural results, and defined the long-term outcomes of TLE in patients with ICD/CRT-D devices (n  =  482, ICD (+)) with lead extractions in patients with standard pacemakers (n  =  1,402, ICD (-)). Demographic, clinical characteristics, and procedural outcomes were ascertained from single, primary operator registry. Long-term survival data were provided by the National Health Fund.

RESULTS

The ICD (+) subgroup had a significantly higher incidence rate of either infective or noninfective indications for TLE. The clinical success rate of extraction was 99.2% in ICD (+) versus 97.4% in ICD (-) (P  =  0.05) at a complication rate of 1.04% versus 2.14% (NS), respectively. In the median follow-up of 3.39 years, 142 patients from the ICD (+) subgroup and 303 from the ICD (-) subgroup died. The highest mortality rate of 41.1% was observed in the ICD (+) subgroup with infective indications. Infection, renal failure, diabetes, and age were the multivariate factors associated with increased mortality in the ICD (+) subgroup.

CONCLUSION

ICD leads remain more vulnerable, with respect to mechanical failure and their propensity to infection, in comparison to pacing leads. Their TLE is very effective at least complication rate, when performed by a highly skilled and experienced operator. However, long-term mortality after their TLE is high and is affected mostly by infections or patient-related factors.

Riata silicone defibrillation lead with normal electrical measures at routine ambulatory check: The role of high-voltage shock testing

AIM

To describe our experience with shock testing for the evaluation of patients with Riata™ leads.

METHODS

Among 51 patients with normal baseline electrical parameters, 20 died during follow-up. Of the remaining 31 patients, 15 underwent the test: In 10 cases a defibrillation testing with ventricular fibrillation (VF) induction and in 5 cases a R-wave-synchronized shock (> 20 J, without inducing VF). The test was performed under sedation with Midazolam.

RESULTS

Twelve patients (80%) had a normal behavior during shock testing: In 8 cases induced VF was correctly detected and treated; in 4 cases of R-wave-synchronized shock electrical parameters remained stable and normal. Three patients (20%) failed the test. One patient with externalized conductors showed a sudden drop of high-voltage impedance (< 10 Ohm) after a 25 J R-wave-synchronized shock. Two other patients with externalized conductors, undergoing defibrillation testing, showed a short-circuit during shock delivery and the implantable cardioverter defibrillator was unable to interrupt VF.

CONCLUSION

In Riata™ leads the delivery of a low current during routine measurement of high-voltage impedance may not reveal a small short circuit, that can only be evident by attempting to deliver a true shock, either for spontaneous arrhythmias or in the context of a shock testing.

Canadian Registry of Implantable Electronic Device Outcomes

Background—

The Riata lead under advisory has posed a unique clinical scenario where inside-out abrasion results in externalization of conductor cables, with a higher risk of electrical failure. We developed a comprehensive registry to assist with clinical management of this lead.

Methods and Results—

This Canadian registry reports the findings of 3763 (74.2% of all Riata leads in Canada) Riata leads under advisory, with a mean follow-up time of 8.9±1.5 years. The overall electrical failure rate was 5.2% at 8 years, with no difference between 7-French and 8-French lead models. Cable externalization was found to be more common in the 8-French model (12.3% versus 5.2%, P <0.0001) and was associated with a higher risk of electrical failure. Predictors of electrical lead failure included cable externalization, higher left ventricular ejection fraction, younger age, higher body mass index, and a passive fixation lead. One patient died due to electrical failure, a further 2 patients survived an event where the device failed to deliver high-voltage therapy. Major complications because of lead extraction were higher when compared with lead abandonment, no difference among lead model observed. Two deaths occurred as a consequence of lead extraction, in the context of an underlying infection.

Conclusions—

The Riata lead under advisory has a steady electrical failure rate over time. There are identifiable predictors of lead failure that can assist with clinical decisions as to whether lead revision should be performed prophylactically.

Implantable Cardiac Defibrillator Lead Failure and Management

The implantable-cardioverter defibrillator (ICD) lead is the most vulnerable component of the ICD system. Despite advanced engineering design, sophisticated manufacturing techniques, and extensive bench, pre-clinical, and clinical testing, lead failure (LF) remains the Achilles' heel of the ICD system. ICD LF has a broad range of adverse outcomes, ranging from intermittent inappropriate pacing to proarrhythmia leading to patient mortality. ICD LF is often considered in the context of design or construction defects, but is more appropriately considered in the context of the finite service life of a mechanical component placed in chemically stressful environment and subjected to continuous mechanical stresses. This clinical review summarizes LF mechanisms, assessment, and differential diagnosis of LF, including lead diagnostics, recent prominent lead recalls, and management of LF and functioning, but recalled leads. Despite recent advances in lead technology, physicians will likely continue to need to understand how to manage patients with transvenous ICD leads.

Long-Term Performance of the Riata/ST Implantable Cardioverter-Defibrillator Lead

Riata and Riata ST implantable cardioverter-defibrillator leads are prone to structural and electrical failure (EF). Our objective was to evaluate Riata/ST lead performance over a long-term follow-up. Of 184 patients having undergone Riata/ST and Riata ST Optim lead implantation from September 2003 to June 2008, 154 patients were evaluated for EF and radiographic conductor externalization (CE). Survival analysis for EF was performed for Riata/ST leads, both for failure-free lead survival and cumulative hazard. Subanalysis on 7Fr leads was performed to evaluate EF and CE rates both for different Riata ST lead management (monitoring vs proactive) and between Riata ST and Riata ST Optim leads. During a mean follow-up of 7 years, Riata/ST lead EF rate was 13% overall. Similar failure-free survival rate was noted for 7Fr as for 8Fr leads (log-rank, p = 0.63). Of all failed leads, 64% failed only after 5 years of follow-up. Compared with the absolute failure rate of 1.84% per device year, cumulative hazard analysis for leads surviving past 5 years revealed an estimated failure rate of 7% per year. No clinical or procedural predictors for EF were found. The subanalysis on 7Fr leads showed an excellent outcome both for a proactive lead management approach as for Optim leads. In conclusion, long-term survival of the Riata/ST lead is impaired with an accelerating EF risk over time. An initial exponential trend was followed by a linear lead failure pattern for leads surviving past 5 years, corresponding to an estimated 7% annual EF rate. These findings may have repercussions on the lead management strategy in patients currently surviving with a Riata/ST lead to prevent significant clinical events like inappropriate shocks or failed device interventions.