The New York Times published an article in their business section (interesting location to put such an article, but I digress) about extracting the Medtronic's advisory Sprint Fidelis defibrillator "cable" recently. (Note to their editors, it's actually a "defibrillator lead" containing multiple wires, not a "cable.") The article quotes some of the best and brightest in the lead extraction field - all of whom are truly experts at the task. It is interesting to note the differences in management style that these guys display: some (Wilkoff) would re-use the lead when it comes times for generator change, while others advise removing the lead at the time of a defibrillator generator (battery) change. There is little mention about placing a new lead next to the old one. Instead, the article suggests that "leaving it in place can make it more difficult to remove later, because of in-grown tissue."
No, that is not the reason to have the lead extracted. On the contrary, that's a reason to leave the lead in place so you can avoid the potential risk of tearing one of the great vessels and bleeding to death during the extraction procedure. After 6 months most of these leads have their "ingrowth" of tissue well-established. The "ingrowth" is not like a cancer that continues to grow. It can become more dense and even calcified over time, however, and the amount of ingrowth varies patient to patient.
Most experienced explanters look for certain characteristics on any lead that needs to be extracted to determine the potential difficulties they might encounter. Leads with more shocking coils are usually more difficult to extract because the coils often become adherent to tissue. Also, leads that passivly fix to the heart by scar formation tend to be harder to extract compared to those that actively screw into the heart muscle (and can have the screw retracted before removal). These are some of the bigger factors to explain why some of these leads come out more easily than others.
Admittedly, sometimes the lead must be extracted because the blood vessel into which the original lead was inserted became completely occluded and a new lead simply cannot be placed next to the old one without removing the old one first. Sometimes there's a desire not to implant a new device from the opposite chest area because of anatomic issues, like a prior mastectomy. Or maybe the lead has become infected, then it MUST be removed because, like a splinter festering in your foot, the infection will never resolve unless the lead is removed in its entirety. These reasons I'd buy as reasons to consider lead extraction. Also, patient preference of anxiety influences the decision to remove the lead, sometimes despite the doctor's best attempts at suggesting alternatives. There will always be a few of these.
But if it is at all possible to place a new lead at the time of battery change, that's seems like a reasonable compromise to me that avoids most future issues with the advisory lead. Certainly, Dr. Wilcoff thinks that the fracture rate is low enough that he'd just re-use it. While this conservative approach might make sense in most instances, is more difficult to justify when a patient is pacemaker-dependent and must have a normally functioning lead at all times for their heart to beat. In these cases, placement of a new lead, especially at the time of device battery change when the risk of infection is unavoidable, might warrant a more aggressive approach to avoid a potentially fatal complication should the lead later fracture. But what to do if the implant vessel is completely occluded and no room exists to place a new lead in such a pacemaker-dependent patient? This is where the toughest clinical issue lies: do you implant a whole new system from the contra-lateral side or just a pace-sense lead and then tunnel the lead to the same side as the others? Or do you extract the lead to make room for a new one? Given the risks involved with extraction, it's hard to know if the "cure" is worse than the disease.
What is certain is that patients with this lead should discuss all of these potential eventualities with their cardiologist or electrophysiololgist before any surgery takes place to develop a game plan should any of these challenges be encountered during routine device battery-change surgeries.