July 17th, 2013
A Surprising ICD Revision
Editor’s Note: This post includes a photo that some readers may find disturbing. The patient has provided consent for the details of his case to be published.
In 1995, a 52-year-old man with chronic atrial fibrillation underwent implantation of an abdominal ICD. As was customary then, the large ICD pulse generator was implanted in the left upper quadrant of the abdomen and connected to an old Guidant Endotak Model 0074 lead that was implanted via the left subclavian vein and then tunneled down to the abdominal pocket. The device served the patient well for years, until its battery depleted in 2003. The old device was replaced by a new, smaller ICD with an appropriate header, and because the defibrillator lead worked well, the smaller ICD pulse generator was left in the abdominal pocket.
Until 2012, the patient underwent routine defibrillator checks in the device clinic without incident. That year, although the lead impedance and capture thresholds remained normal, intermittent periods of noise with nonphysiologic short RR intervals (suggestive of possible impending lead fracture) began to appear on the device checks. The patient was not pacemaker-dependent, so the electrophysiologist decided to wait until the battery would need to be replaced (7 months later) before revising the patient’s ICD system. The EP reasoned that at that time a new defibrillator lead could be implanted and connected to a more conventional VVIR ICD pulse generator implanted in the upper chest area. The old pulse generator could then be removed from the abdomen, and the old lead would be capped and left in place.
The day for surgery arrived. The patient, now 70 years old, felt fine: no fever, chills, or other unusual preoperative symptoms. A venogram performed immediately before the procedure revealed patent left-axillary and subclavian veins. So the decision was made to first implant the new ICD on the same side where the patient’s original defibrillator was implanted, then to remove the old ICD pulse generator from the abdomen. Preoperative antibiotics were administered, and the new single-chamber ICD was implanted via the left-axillary approach without a hitch. A dressing was applied to the wound, and preparations were made to explant the abdominal pulse generator.
The lower abdominal area was similarly prepped and draped. Local anesthetic was infiltrated over the prior abdominal scan, and an incision was made at this location. By means of electrocautery dissection, the incision was carried to the pulse generator capsule, which appeared to be quite thick but not inflamed. The fibrous capsule surrounding the pulse generator was then opened. What was found was startling.
Inside the pulse generator pocket was the device and lead system, surrounded by thick, odorless fluid that looked, for lack of a better phrase, like wet, brown mud. After the suture holding the device’s header to the pocket wall was cut, the device was extracted from the pocket. A portion of the lead was also cut and removed. Here is a picture of the removed device:
- How do you explain the startling appearance of the removed device?
- With the “muddied” device in your hand, what is your next step in caring for this patient?
- What is the likelihood of infection in this scenario?
- What insights, if any, do clinical guidelines offer for handling a situation like this
July 24, 2013
1. The appearance is strongly indicative of some type of infection, although atypical for a bacterial process. A reader has suggested a parasitic infection, which is an interesting possibility. Benign processes are almost uniformly serosanguinous; this appearance is quite different. The lack of systemic signs and symptoms does not dissuade me from strongly considering infection; many cardiac device infections do not result in systemic illness.
2. With the device in hand, I would ask that Gram stain and cultures be performed from the device. Blood cultures should be done as well. The entire device should be sent to pathology; a sample of the thickened capsule should also be sent for pathology review. I would consider explanting the just-implanted device, as that would be much easier to do now than later. His arrhythmic risk could be covered with use of a LifeVest (see Chung MK et al., JACC 2010; 56:194). The original indication for the ICD and whether there have been events in the interim are not clear but would affect the decision about whether to use a LifeVest.
3. I think the risk for a localized infection is significant but needs confirmation.
4. The 2010 AHA Update on Cardiovascular Implantable Device Infections is an excellent resource for all physicians who care for such patients. The take-home message is to have a high level of suspicion and to treat aggressively.
July 31, 2013
Gram stain of the debris showed no white cells or organisms. The capsule was removed in its entirety. Cultures of the pocket capsule tissue, blood cultures, and cultures of the fluid all came back showing no growth. The patient had been on warfarin (and later rivaroxaban) for his atrial fibrillation.
Of course, at the time of the procedure, the culture results were not known. So the new ICD pocket was re-draped and prepped, and the wound was opened to find the tunneled 0074 ICD lead’s tie-down sleeve. This was released, the lead was cut and capped, and the distal portion was withdrawn back to the abdominal pocket to prevent a “wick” extending from the abdominal wound to the new ICD system. The new ICD wound was re-closed.
The abdominal would was irrigated with antibiotic saline solution and closed primarily, and a Jackson-Pratt drain was placed to remove dead space and prevent seroma formation. The antibiotic was expanded to vancomycin only (from cefazolin), continued for 3 days, and then discontinued when the Jackson-Pratt drain was removed.
The patient was seen by an ID specialist, who agreed that stopping antibiotics and observing was the best scenario. The patient was seen in follow-up 10 days later and has done well.
Note that this case was first published on my blog (Dr. Wes), and I would like to credit Dr. Edward Schloss for coming up with the correct answer before I revealed it. Here is an excerpt from Dr. Schloss’ astute response on my blog:
“I’ve come across this exact situation 3 or 4 times before. We have seen this in second or later pulse-generator changes and more commonly in abdominal pockets.
“When an ICD is replaced into a chronic ICD pocket, the remaining open space in the pocket can serve as a cavity that can collect debris. If the pocket capsule is not dissected away partially or completely, the closed pocket will act as a protected closed space. Any remaining blood from the prior surgery will have no place to go. As the generator rubs in the interior of the capsule, the capsule material will slough off and collect in the pocket. Because there is no communication with the subcutaneous space, the debris will simply fill the additional space. The debris is not infectious.
“This is not seen at the time of first pulse-generator changes, because the pocket forms around the new device as the remaining surgical blood drains away. I suspect it happens less often in pectoral pockets, because typically we have to dissect the pocket at least a bit to fit the new device in place. I think any form of extrapocket communication with the subcutaneous tissue will prevent the process. In addition, these devices generally don’t get banged around as much as the abdominal devices.
“Nowadays, I never close a chronic device pocket without at least some form or capsulotomy. So far, I have not seen this happen again.”