Learning while extracting: ‘pacing’ lessons from the world of lead extraction

Percutaneous lead extraction has evolved over the years and is the method of choice for device removal [1–3]. Despite a good safety record for transvenous extraction, these procedures continue to be associated with life-threatening complications, like tamponade, hemothorax, pulmonary embolism and death [4].

The goal of extraction techniques of chronic pacemaker and defibrillator leads is to present an approach that is successful in extracting all leads and minimizes or eliminates complications. Unfortunately, lead extraction scenarios may be very heterogeneous [5]. As known, after implantation a well-orchestrated response to tissue injury begins with thrombus formation, acute inflammatory cells and fibroblasts. Granulation tissue forms and progresses to a fibrous connective tissue scar. After few months, the electrode-myocardial interface of the hearts is characterized by intense endocardial fibrosis. Fibrosis occurs predominantly on areas of lead that contact the vascular endothelium or endocardium (like the venous entry site, the superior vena cava and the lead tip) [6] and may be affected by clinical (patient-related) and technical (device-related) factors – two sides of the same coin.

On the one hand, there are the patient-related factors, like age (young patients often show a massive fibrotic reaction) and anatomy, which are, by definition, ‘non-modifiable’. On the other one, we have the device-related factors, which are ‘modifiable’ and may be controlled at the time of implantation. This must be our playground. Implanting the right device in the right way may reduce significantly tissue in-growth. Just think of the simple role of device shape. The quality of the fibrous tissue within the pacemaker pocket, surrounding the pacemaker and lead body, usually represents the characteristics of the intravascular fibrous tissue. As using more physiological device shapes we reduce overall skin pressure, [7] the under-skin trauma and, probably, the future fibrous in-growth, so we could do with cardiac leads. Lessons from the world of lead extractions taught that the more ‘extractable’ leads are the left ventricular ones (i.e., coronary sinus leads), with a 70% success rate by manual extraction [8]. Is this only by chance? Probably not. Reasonably, this is the result of appropriate lead features (like the absence of fixation mechanisms, an isodiametric structure, a prevalent polyurethane insulation) in combination with locations ‘suitable’ for lead extraction (i.e., a smooth cardiac vein).

Lead characteristics potentially affecting fibrosis include the tip design (fixation mechanisms and drug eluting strategy) and the lead body properties (diameter, insulator and defibrillating coil design). Regarding the tip, differently from passive fixation mechanisms (i.e., tines), which are more traumatic in the long term, impeding tip debridement from endocardium and provoking proximal block during manual traction, screw-in leads resulted easier to remove [6]. Then, the addition of a steroid eluting technology has further reduced inflammation and fibrosis at the electrode-tissue interface [9].

However, the large amount of lead-tissue contact is along the lead course, where we encounter the majority of fibrous adherences. Thus the pro-inflammatory and pro-fibrotic role of different lead insulating materials is not valueless. Silicone leads are more viscous and frictioning than polyurethane leads, but the latter have the disadvantage of bioinstability, with the risk of a chemical mediated tissue injury. Recent preliminary data seem to suggest a better extraction profile for hybrid silicone-polyurethane materials, which could combine benefits of both insulators [10].

Additional problems are encountered with ICD leads. Besides having similar components to pacing leads, they also contain single or dual high-voltage shock coils to deliver defibrillation therapy [11]. In the last decade, the aggressive fibrosis surrounding coils has lucky been reduced by the use of single coil design [12], isodiametric structures, flat wire coil design, backfilling materials [13] and Gore-Tex covers [14,15]. Although all these measures have significantly improved the extraction profile of ICD leads, much still remain to be done.

Finally, a few words on lead implantation technique. The lead has to be implanted properly, using a low traumatic venous access (cephalic or axillary), avoiding complication related to the intra-thoracic rib-clavicle angle and placed at the level of medium interventricular septum with a physiological curve. It means avoiding unnecessary loops (responsible of future adherences) and guarantying a suitable sheath course (in the case of a future extraction).

In conclusion, today our attention about lead extraction should be focused not on repeating already published experiences, whose outcomes are well known. We should focus primarily on the removal efficacy and the extractive impact of specific prosthetic technologies. At the present, this is the best we can do, while waiting for new wireless devices. But, that’s another story. Until then, let’s keep in mind that ounce of prevention is better than a pound of cure.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.