Cardiac implantable electronic device infection

DIAGNOSIS

Prompt and accurate diagnosis of CIED infection is critical as it allows for early management with antibiotic therapy and device removal. As the number of CIED implantations increases, providers on the front lines—emergency, family practice, and internal medicine physicians—will play an increasing role in recognizing and diagnosing CIED infection. Patients with CIED infection present with a range of signs and symptoms including fever, chills, erythema, swelling, drainage, tenderness, malaise, erosion, and warmth of the skin overlying the generator pocket.² In 55% of cases, patients present with localized pocket infection, while the remaining patients have signs of an endovascular infection without obvious pocket involvement.¹² Localized pocket infection is more common during the first year after device implantation. CIED-associated endovascular infections occur more commonly in patients with multiple comorbidities including diabetes, renal failure, prior heart valve operation, rheumatic heart disease, and prior bloodstream infection.² Despite the theoretical divide in CIED infections (endovascular vs pocket), overlap is common: many patients with pocket infection show evidence of bacteremia and vegetations on the leads.

Physical examination of the pocket is critical as it may reveal visible signs of infection and support the diagnosis of localized pocket infection (Figure 1). Blood cultures are essential and should be collected before starting antibiotic therapy. Culture results assist in the diagnosis of CIED infection and also help identify the microorganism involved, and this information helps tailor the choice and duration of antibiotic therapy. Echocardiography (transthoracic and transesophageal) can assist the clinician in the diagnosis of CIED infection but requires careful interpretation because some patients with no signs or symptoms of infection can have small fibrinous strands or thrombi attached to the CIED leads.¹⁴ These findings should only be interpreted in correlation to the clinical presentation.

Diagnosing pocket infection from the physical examination can be difficult due to the often subtle manifestations of the underlying pathophysiology and because visible changes to the pocket can occur over weeks and months. Furthermore, differentiating superficial infection, hematoma, seroma, and allergic reactions from deep pocket infection can be challenging. In cases when the diagnosis is not clear and there are no systemic findings of infection, conservative management with close follow-up is reasonable. Similarly, the diagnosis of endovascular infection is sometimes delayed because the symptoms are not very specific or because of a lack of awareness of the presence of a CIED and its role in endovascular infection.

MANAGEMENT

A multidisciplinary approach involving cardiology, infectious disease, electrophysiology, and cardiothoracic surgery teams is required to optimize outcomes in patients with CIED infection. CIED infection is particularly difficult to treat with antibiotic therapy alone because it involves infection of an implanted device and an associated biofilm that is resistant to the effects of antibiotics. Once infection is confirmed, antibiotic therapy serves as an adjunct to the complete removal of the hardware. Most patients receive 2 weeks of intravenous antibiotics after removal of an infected CIED, with longer courses for patients with Staphylococcus aureus infection or documented endocarditis.²¹

Infectious disease consultation is paramount in order to choose the appropriate type and duration of antibiotic therapy. Conservative approaches that involve using antibiotics alone or incomplete system removal have high failure rates with high rates of morbidity and mortality.^13,21–28 However, chronic antibiotic suppressive therapy may be considered as a palliative measure for patients who are not candidates for lead extraction.

DEVICE REMOVAL

Confirmation of CIED infection is a class I indication for device removal and the patient should be referred to an electrophysiologist. Transvenous lead extraction (TLE) is a percutaneous procedure performed by the electrophysiologist in the electrophysiology laboratory or hybrid operating room with cardiothoracic surgery support, and it is generally performed under general anesthesia with invasive hemodynamic monitoring. After opening and debriding the infected pocket, the generator is disconnected from the leads. After the lead tips are unscrewed from the myocardium, gentle traction is applied to determine if the leads can easily be removed. If traction is unsuccessful, additional tools (both powered or mechanical sheaths) are used to complete the lead extraction²⁹; the goal is to lyse and free the fibrotic attachments between parallel leads and between the leads and vessel wall or the myocardium. Once the lead is freed from the adhesions it can be removed safely.

The incidence of major complications with lead extraction is low (1.8%), but the procedure can be life-threatening.³⁰ Major complications include cardiac avulsion, vascular laceration, pericardial effusion, tamponade, hemothorax, valve injury, and death during the procedure.³⁰ Risk factors for major complications with TLE include renal failure, low body mass index, and the presence of a defibrillator coil on the lead.^30,31 In a large cohort of more than 3,000 patients requiring 6,000 TLE procedures at our tertiary care center, the incidence of catastrophic complications that required emergency cardiac surgery or vascular intervention was 0.8%.³² Many of these patients were rescued through emergency surgical repair of a venous laceration or cardiac perforation but still had an in-hospital mortality rate of 36%. Surgical lead extraction is usually performed if percutaneous lead extraction has failed, if epicardial leads are present, if large vegetations are attached to the leads, or if surgery is warranted for valvular involvement with endocarditis (Figure 2).¹⁴