Case Report: A nine year follow-up for a pacemaker generator poly-tetra-fluoro-ethylene coating for allergic reactions to pacemaker compounds

Introduction

Pacemaker system hypersensitivity is a rare complication of cardiac pacing and diagnosis is usually difficult, and is often delayed¹. In fact, bacterial infection is initially suspected routinely rather than allergy to the pacemaker components¹. Management of this condition is difficult and not well established.

Here, we report a patient who developed repeated sterile skin necrosis leading to generator externalization. Prick testing was of a doubtful interpretation. The patient recovered after implantation of a poly-tetra-fluoro-ethylene (PTFE)-coated pacemaker generator in a retropectoral position.

Case report

A 75-year-old man with symptomatic complete atrioventricular block received a dual chamber pacemaker (MEDTRONIC SIGMA DR) in November 2000. The patient required two generator re-implantations in March 2005 and August 2007 due to sterile skin necrosis with externalization of the pacemaker generator. A St Jude Medical IDENTITY DR pacemaker was used in the two replacements.

In May 2009, the patient presented with a third externalisation of the pacemaker generator, with localized swelling and redness in the implanted area. The patient had no fever, and inflammatory parameters during blood testing were negative; except the patient had a high eosinophil fraction (0.59×10³/L; normal range: 0.0–0.5 ×10³/L). Blood cultures, bacterial swabs and cultures of the material taken gave negative results. Swabs from pacemaker pocket showed that C-reactive protein and procalcitonin were negative. We performed a skin prick test using a standard battery (not including titanium). Little positivity was found to nickel and chrome batteries, but skin application of another pacemaker generator (St Jude Medical IDENTITY DR) produced a suggestive skin response.

The patient underwent removal of the old pacemaker system and re-implantation of a new pacemaker system. The generator (Saint Jude Medical Victory XLDR) was entirely coated with PTFE sheet and implanted in the left chest wall in a retro pectoral position (Figure 1). The procedure was uneventful and the patient was discharged in good condition.

Figure 1. Poly-tetra-fluoro-ethylene (PTFE)-coated pacemaker implantation.

(A) Entirely coated pacemaker generator with PTFE sheet; (B) coated generator connected to two leads implanted in retropectoral position.

After 23 months of regular follow-up, the generator moved from a retropectoral to a subcutaneous position on chest CT scan. No recurrence of externalization or cutaneous signs was observed up to nine years after implantation

Discussion

Pacemaker component allergy is a rare but well established complication of cardiac pacing. It was first reported by Raque and Goldschmidt² in 1970 in a patient presenting with eczematous dermatitis developed overlying the pacemaker site within 3 weeks of implantation. Since then various reports have been published^3,4. Several clinical presentations are observed varying from local pain to systemic manifestations. Pacemaker-mediated dermatitis is thought to be a delayed hypersensitivity type 3 or 4 mediated reaction⁵. The time taken for sensitivity to develop varies from months to years⁵. In our case, the allergic process occurred several years after implantation. The allergen can be located in the “CAN” or other components of the pacing system. Titanium, nickel and epoxy resin are the most common allergens⁶.

Diagnosis of pace maker allergy is difficult and infection must be ruled out before any hypersensitivity investigation. Skin patch tests are helpful but not always contributive since their sensitivity is not very high. In our patient, skin tests showed a doubtful reaction to nickel and chrome. Titanium is the main component of pacemaker generator, is not included in the standard battery and was very likely to be an allergen because skin reaction was only observed above the generator. Otherwise, Déry and colleagues⁶ suggested that titanium test is unreliable because this test is performed using titanium tetrachloride, which must be highly diluted with water and quickly hydrolyzed to insoluble titanium dioxide. A positive reaction to nickel can be found in up to 20% of the population⁷; therefore nickel tests should be interpreted with caution. Furthermore, skin tests reading can be extended to 72 hours to have more positive results⁸. A positive reaction to intracutaneous testing on the affected patient’s serum incubated with small pieces of titanium for 1 month in a patient who had negative results on patch testing to titanium was reported by Yamauchi et al.⁹. In our patient, clinical presentation is very suggestive of hypersensitivity and titanium is very likely to be an allergen because skin reaction was only observed above the generator (composed mainly of titanium).

Treatments of contact dermatitis have been described in various case reports. There is a role for topical corticosteroid that can reduce skin symptoms, but recurrence is common¹⁰. The only complete treatment is the removal of the allergen, and the use of a hypoallergenic material. One option, as described by Syburra et al. and Andrews and Scheinman^1,11, is the use of gold-coated generator. PTFE sheet coating technique was first reported in Japan^8,12–14. This technique seems to be an effective method despite theoretical risk of PTFE hypersensitivity. In our patient, lack of recurrence confirms pacemaker component allergy and effectiveness of PTFE coating to prevent it.

Conclusion

Although pacemaker allergy is a rare condition, its recognition is important considering the widespread use of pacing and defibrillation systems. Allergic reaction can occur early or be delayed. It is recommended to rule out this diagnosis in the case of pacemaker pocket inflammation without signs of an infection. A negative skin test should not exclude diagnosis. We report in the present case that removal of the system components and the use of PTFE-coated materials are effective to prevent recurrence with a long follow-up.

Consent

Written informed consent for publication of the clinical details and images was obtained from the patient.

Data availability

All data underlying the results are available as part of the article and no additional source data are required.