Long-term electrical performance of Attain Performa quadripolar left ventricular leads with all steroid-eluting electrodes: Results from a large worldwide clinical trial.

BACKGROUND: Steroid-eluting (SE) electrodes suppress local inflammation and lower pacing capture thresholds (PCT); however, their effectiveness on quadripolar left ventricular (LV) leads in the cardiac vein is not fully studied. We evaluated the effectiveness of SE on all four LV pacing electrodes in human subjects enrolled in the Medtronic Attain® Performa™ quadripolar LV lead study. METHODS: A total of 1,097 subjects were included in this evaluation. At each follow-up visit (1, 3, 6, and 12 months), LV PCT and pacing impedance were measured using either manual or automated testing methods. Summary statistics for PCT and impedance values were obtained for implant and each scheduled follow-up visit for all lead models. RESULTS: Average extended bipolar (LV electrode to right ventricular Coil) PCTs for the four LV SE pacing electrodes (LV1, LV2, LV3, and LV4) on the three shapes of the quadripolar LV leads were 1.06 ± 0.97 V, 1.38 ± 1.26 V, 1.51 ± 1.33 V, and 2.25 ± 1.63 V, respectively, at 0.5-ms pulse width. PCTs remained low and stable throughout the 12-month follow-up period. CONCLUSION: This clinical trial demonstrated that SE on all LV pacing electrodes is associated with low and stable PCTs for all quadripolar LV lead electrodes, resulting in multiple viable vectors for LV pacing. The large number of available vectors facilitates basal pacing, avoidance of PNS, and potentially prolongs generator longevity due to lower PCTs.

Two-year extractability of novel left ventricular, active fixation leads in the sheep model.

BACKGROUND: A cardiac lead with a side helix for active fixation to the coronary vein wall (Attain Stability® , Model 20066, Medtronic, Minneapolis, MN, USA) recently received CE Mark. The lead is designed to improve left ventricular (LV) placement and reduce dislodgement rates. The extractability of this active fixation LV lead has not been studied extensively. METHODS: Seventeen sheep were implanted with either an LV lead with a side helix (Model 20066, Model 20096, Medtronic) or a unipolar LV lead (Model 4193, Medtronic) as a control. Leads were extracted at approximately 26, 52, or 118 weeks. Standard extraction methodology was employed with quantitative traction up to 907 g (2 lbs.) using a locking stylet. Gross pathology and histology of the heart with particular attention to the lead tracts were performed. RESULTS: All leads were successfully removed in their entirety and required significantly less than 1 kg of traction force. The side helix disengaged from the vein as designed and resulted in no complications. No cardiac tissue was observed on any extracted lead. Gross pathology and histology were devoid of any helix-induced lesions in the vascular structures. The epicardium over the side helix was normal and the fibrotic reaction around the helix was not significantly different from that around the nonhelix portions of the study leads or the control lead. CONCLUSION: Extraction of the side helix, active fixation LV lead from the coronary veins in the sheep model is safe, without procedural complexity, and free of complications after long-term LV lead implant duration.

Real-World Assessment of Acute Left Ventricular Lead Implant Success and Complication Rates: Results from the Attain Success Clinical Trial.

BACKGROUND: Left ventricular lead (LVL) implant success rates have historically ranged between 70.5% and 95.5%. To date, there are few large studies that evaluate LVL implant success utilizing a single family of delivery catheters and leads. The Attain Success study was a prospective nonrandomized multicenter global study with the main objectives of assessing single-system LVL implant success and complication rates. METHODS: Patients undergoing cardiac resynchronization therapy implantation were eligible for enrollment. There was no prespecified level of experience for investigator participation. LVL implant success and complication rates were assessed though 3 months of follow-up. RESULTS: A total of 2,014 patients (69.1 ± 12.0 years, 71% male and 38% atrial fibrillation) were enrolled from 114 centers with a follow-up of 3.5 ± 2.1 months. Coronary sinus cannulation success rate was 96.4% with Attain Family delivery catheters. Implant success rate for Attain Family leads using Attain Family catheters was 94.0%; overall LVL implant success rate was 97.1%. Median procedure time was 4 minutes for cannulation and 9 minutes for LVL placement. Median fluoroscopy time was 17 minutes and median contrast used was 25 cc. There were 55 catheter or LVL-related complications in 53 subjects; the majority were LVL dislodgements (34, 1.7%) and extracardiac stimulation (11, 0.5%). The Kaplan-Meier estimate of the 3-month complication probability was 2.6%. CONCLUSION: This study represents the largest prospective evaluation of LVL implantation to date, revealing a high LVL implant success rate and low complication rate using a single family of leads and delivery catheters.

Effect of Steroid Elution on Electrical Performance and Tissue Responses in Quadripolar Left Ventricular Cardiac Vein Leads.

INTRODUCTION: The use of steroid elution (SE) electrode in a cardiac pacing lead is known to suppress myocardial inflammation to lower pacing thresholds (PTs). SE has been widely utilized on the distal electrode of left ventricular cardiac vein (LVCV) leads used in cardiac resynchronization therapy (CRT). However, no paired comparison in effect of SE has been studied in proximal electrodes of quadripolar LVCV leads. METHODS: We evaluated electrical performance and tissue responses of quadripolar LVCV lead electrodes with and without SE in two canine studies with a total of 14 canines. Extended bipolar PT and pacing impedance of the LVCV electrodes to right ventricle coil were collected via an implantable CRT device/programmer or a percutaneous threshold analyzer/pacing analyzer at weeks 0, 1, 2, 4, 6, 8, and 12. Gross and histopathological examinations of the canines were performed at the end of the studies. RESULTS: Our preclinical studies showed that SE had significant effects on the long-term pacing performance of quadripolar LVCV leads. The SE tip and ring electrodes reduced postimplant PT peak and chronic PT, P = 0.038. Histological examination of the perilead tissue capsules at 12 weeks showed a reduced thickness for the location of SE electrodes. CONCLUSION: SE electrodes in quadripolar LVCV leads lower the PTs, and therefore may potentially reduce long-term current drain of CRT systems, thus improving the device longevity. These preclinical data serve as rationale to include SE on proximal electrodes for the Attain Performa LVCV leads and future quadripolar LVCV leads development.

Novel active fixation mechanism permits precise placement of a left ventricular lead: early results from a multicenter clinical study.

BACKGROUND: Left ventricular (LV) lead implantation for cardiac resynchronization therapy (CRT) is associated with lead dislodgement rates ranging from 3% to 10%, and some implant approaches to prevent dislodgement may contribute to suboptimal CRT response. We report our early human experience with an LV lead with a side helix for active fixation to the coronary vein wall. OBJECTIVES: To assess the feasibility and safety of the Model 20066 LV lead and to evaluate the implant procedure. METHODS: The Model 20066 is a 4-F bipolar steroid eluting lead that has a small exposed side helix and can be delivered using a guidewire or stylet. At the desired vein location, the lead body is rotated clockwise until the helix is fixated. This study was a single-arm, prospective, nonrandomized trial that enrolled 40 patients from 4 centers who met standard indications for CRT. RESULTS: The lead was successfully implanted in 39 of 40 (98%) patients. In 38 of 40 (95%) patients, the implanters were successful at implanting at a predetermined target site. There were no Model 20066 LV lead dislodgements reported within 12 months of follow-up. The electrical performance of the tip and ring electrodes was stable through the 12-month follow-up visit and similar to other LV leads. Overall lead handling was rated as acceptable for all implants. CONCLUSION: This new LV lead specifically designed with an active fixation mechanism for stability and precise placement was successfully and safely deployed in the coronary vasculature.