Weapons development programme before the lead war

This editorial refers to ‘Percutaneous extraction of cardiac pacemaker and implantable cardioverter defibrillator leads with evolution mechanical dilator sheath: a single-centre experience’ by A. Oto et al., on page 543. We are probably sitting on a minefield. The management of patients has been improved by the development of new technologies, and we are enthusiastic about new solutions for our patients. The rate of pacemaker and implantable cardioverter-defibrillator (ICD) implantations is increasing with the ageing population and the development of new indications. Although conferring obvious benefits for patients, the use of these devices is associated with serious complications. We will have to face an exponential increase in pacemaker and ICD leads extractions. As the rate of cardiac devices implanted increases rapidly worldwide, extractions of chronically implanted endocardial leads are being attempted by a growing number of physicians. Significant progress has been made, providing implanting physicians with safer techniques and effective tools to extract pacing and ICD leads, including locking stylets, dilator sheaths, transfemoral snares, retrieval baskets, and laser-assisted sheaths.1,2 However, extraction of chronically implanted transvenous lead systems remains a challenging and risky procedure, associated with considerable morbidity and mortality.3 After implantation, transvenous leads usually undergo fibrotic encapsulation by activation of different cellular and humoral immune mechanisms. With time, this fibrotic encapsulation induces some extremely strong adherences of the leads. The number of ICD leads to extract is also increasing. We have no scientific proof of a higher complication rate with these leads. However the coils, the stiffness of these leads can make them more difficult to extract. Using the FDA (Food and Drug Administration)’s MAUDE (Manufacturer and User Facility Device Experience) database, Hauser et al.4 found that the majority of deaths and injuries involved ICD leads. Moreover, an ICD is a relative new device comparative to pacemaker, and we actually extract relatively recent ICD leads and only begin to manage old and very old ICD leads. The problem is only at dawn. The same will probably occur with coronary sinus leads. We have to wait for the results with old leads to really appreciate the risk of their extraction. Another increasing population could be more risky: children and young adult. Large series are required to confirm this observation, but Dilber et al.5 found a success rate of only 69.7% for lead older than 3 years in young age patients. Children are known to heal with scarring and they can develop more fibrous tissue and more adherences on their leads. Moreover, the size of the ICD lead with a long coil is not adapted to the size of the child's right ventricle inducing adherences between the coil and the tricuspid valve. So, we will face not only an increasing number of lead extractions but also an increasing number of difficult leads extractions. This gives rise to several questions, including the question what is the best technique for our patients? The extraction techniques can be subdivided in three groups: Choosing one of these techniques is the first step of the procedure. The femoral approach is the technique of choice when the lead is damaged or cut without any access via the vein used for implantation. Apart from this, it is fashionable to use the technique based on sheath dissection. Sheath allows counter-traction and new lead implantation. However, a major concern is about the risk of injury to the right atrium and superior vena cava with sheaths. Vena cava injury is extremely difficult to cure surgically. The vector of traction on the lead and the vein and the possible contact between the vein wall and the tip of the sheath could increase this risk. In contrast, traction via the femoral or jugular access is performed along the anatomical axis and can decrease the risk. In the MAUDE registry, 23 deaths occurred during laser-assisted extractions. In the European excimer-laser-assisted lead extraction experience, 10 perforations occurred in 294 patients (3.4%).7 In contrast, the multicentre randomized Pacing Lead Extraction with the EXcimEr Sheath (PLEXES)1 trial in 301 patients has found that laser-assisted extraction was more efficacious than non-laser techniques. Laser-assisted extraction resulted in a significantly higher proportion of complete lead removals than non-laser methods (94 vs. 64%; P = 0.001). Several large single-centre reports have shown that laser-assisted lead extraction was successful and reasonably safe2,8 and there is no comparative large study with other extraction techniques. A recent multicentre study9 which compared the femoral approach and laser-assisted lead extraction has found no significant difference between two approaches with respect to procedural success and complication rates. Major procedural complications were observed in 3% of the patients; however, the leads in this study were implanted over 4 years earlier, which highlights difficulties comparing the different series involving lead extraction. Many leads are easy to extract, and 25% do not require additional tools. However, a low complication rate may be reported if only leads easy to extract have been studied. On the contrary, some series which reported on leads which were difficult to extract are likely to report a higher mortality rate. Therefore, there is a need for a randomized study to compare the different techniques. So far, the important observation in the reported series is that a difficult lead can be successfully and safely extracted by changing the approach. the upper approach via the implanted vein using a sheath (mechanical, laser-assisted, electro dissection, rotational cutting) moved along the lead body; the femoral approach; the jugular approach.6 Oto et al.10 shared their experience with a newly developed hand-powered device, the Evolution mechanical dilator sheath (Cook Medical Inc., Bloomington, IN, USA) with a rotational mechanism, and a cutting metal screw at the tip of the inner sheath. The rotating screw allows the sheath to move along the lead by cutting the adhesions. Additionally, a shorter Evolution Shortie mechanical dilator sheath is used with a sharper blade to overcome the problem of scarred or calcified tissue in the proximal part of the venous access. This is the second publication with the efficacy and safety of these sheaths.11 The results are interesting even if the initial success rate without other tools was relatively low (77 and 82%). Localization of very dense or calcified fibrous tissue especially in the subclavian vein or the inominate vein is frequent on very old leads and compromises the progression of laser sheath or the slide of the lead during a femoral extraction. The Evolution mechanical dilator sheath seems to be effective in dissecting fibrous tissue and can be used at least as an additional tool. We should not neglect the cost of different tools and the cost could be important when the efficacy and safety are equivalent. The presence of several leads with adhesion between them could be a major limitation of the technique. The range of times of lead implantation varied in reported series, but it was very seldom that 12–24 months leads required additional tool for extraction. Further investigation is required to evaluate safety, success, and complication rates with the Evolution mechanical dilator sheath. We have to sharpen our weapons and review our strategies before the battle, but the need to develop new tools must not lead to the underestimation of the importance of training and safety measures as outlined in the Heart Rhythm Society expert consensus.3 Conflict of interest: D.K., T.M., C.M., and S.K. are consultants for Medtronic, Boston Scientific, Sorin, and St. Jude Medical. D.K. is also a consultant for Sanofi Aventis.