Strategies to increase the INGEVITY lead strength during lead extraction procedures based on laboratory bench testing

Figures

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  FIGURE 1. Lead extraction test method set‐up. Picture of the Instron load frame used for lead extraction testing. Critical bending of a right atrial lead implant with a superior vena cava/innominate structure adhesion is demonstrated [Color figure can be viewed at wileyonlinelibrary.com]

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  FIGURE 2. Helix retraction turn count testing results. Test results for helix retraction turn count testing by stylet type and test condition [Color figure can be viewed at wileyonlinelibrary.com]

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  FIGURE 3. Example test result. Example of results from tensile test to failure for “attached only at the tip” test scenario (INGEVITY 52 cm lead, Cook Liberator locking stylet, terminal cut off of lead, suture and Cook One‐Tie used). (A) Shows drawing of INGEVITY lead tip after load has been applied causing the inner components to stretch and fracture. (B) Shows the force versus displacement curve with labels of various component failures during the test [Color figure can be viewed at wileyonlinelibrary.com]

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  FIGURE 4. Comparison of damaged and nondamaged Polyurethane Body Tubing in SVC/innominate scar and tip attachment model. Load versus Extension plots of test cases with scar attachment at the lead tip and within the Superior Vena Cava/Innominate structures. The Black line includes data for a sample without damage to the polyurethane body tubing. The red dotted line includes data for a sample with damage to the polyurethane body tubing illustrating early PU failure and subsequent inner coil failure [Color figure can be viewed at wileyonlinelibrary.com]

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  FIGURE 5. Lead extraction with the use of a fully engaged Snare. Force versus displacement curve using a fully engaged (see text) Needle Eye Snare. Traction force is borne by the locking stylet and the snare. Failure occurs at maximum force (13 lbs) when the locking stylet breaks [Color figure can be viewed at wileyonlinelibrary.com]

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  FIGURE 6. Test data using a combined inferior‐superior approach. Maximum Force data plotted for all snare test cases. Two findings are demonstrated. (1) The blue solid circles demonstrate when a Needle Eye Snare is placed distally on the lead (only 1.27 cm [0.5 inch] proximal to the anode) less force is required before lead component failure than a more proximal snare position (5.08 cm [2.0 inch]). Original testing conducted in units of inches for snare location. Traction forces of 13 lbs or greater were tolerated prior to locking stylet failure. (2) The engagement of the locking stylet within the inner sheath is critical (Blue open circle versus red diamonds). Pulling the lead/locking stylet into the inner sheath results in kinking the stylet and firmly engages the locking stylet as part of the extraction rail [Color figure can be viewed at wileyonlinelibrary.com]

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  FIGURE 7. Demonstration of the snaring technique. (A) Needle Eye Snare is used to snare the lead (A) and create a substantially harsh kink in the lead, driving the lead body to ∼180‐degree bend, and prolapse the lead fully into the inner sheath of the snare. (B) Fluoroscopic image (C) demonstrating the snare's firm grip and harsh kink anchoring the distal lead. The locking stylet provides support for an effective extraction rail [Color figure can be viewed at wileyonlinelibrary.com]