Does the MICRA (MicroElectrode Recording Assembly) pacemaker have a lower risk of infection compared to traditional pacemakers?

MICRA Pacemaker Has Lower Infection Risk Than Traditional Pacemakers

The MICRA leadless pacemaker carries significantly less potential for infection compared to traditional transvenous pacemakers due to the absence of leads and subcutaneous pocket, which are the primary sites for infection in conventional systems.

Infection Risk Comparison

Traditional Pacemaker Infection Risk

Traditional transvenous pacemakers have reported infection rates of approximately 4%, with a disproportionate increase in these rates compared to the increase in CIED implantation 1. These infections typically involve:

• Pocket infections (most common site)
• Lead-related infections
• Systemic infections/endocarditis

The most common pathogens causing these infections are:

• Coagulase-negative staphylococci (38%)
• Staphylococcus aureus (31%)
• Gram-negative bacteria (9%)

MICRA Leadless Pacemaker Advantages

The MICRA leadless pacemaker offers significant advantages in reducing infection risk:

1. No transvenous leads - eliminates the risk of lead-related infections 2
2. No subcutaneous pocket - eliminates pocket infections 2
3. Miniature technology with less invasive implantation 2
4. Shorter procedure time, reducing exposure to potential contaminants 2

Evidence Supporting Lower Infection Risk

The Micra post-approval registry provides compelling evidence of the safety of leadless pacemakers in patients with pre-existing infections. In a study of 105 patients with prior CIED infection who underwent Micra implantation:

• 99% successful implantation rate
• No Micra devices required removal due to infection during follow-up
• Leadless pacemakers proved to be a safe alternative for patients with previous CIED infections 3

This data strongly suggests that the MICRA system provides a viable solution for patients with a history of device infections, with virtually no recurrent infections requiring device removal.

Clinical Applications

The MICRA leadless pacemaker is particularly beneficial for:

• Patients with previous CIED infections 3
• Patients without conventional venous access options 2
• Older patients with atrial fibrillation and symptomatic bradycardia 2
• Patients at high risk for conventional pacemaker infections

Important Caveats

Despite the significantly lower infection risk, clinicians should be aware that:

1. Leadless pacemaker infections, while extremely rare, are still possible as demonstrated in case reports 4
2. If infection occurs, device extraction may be challenging, especially with longer implant durations 5
3. If a leadless device becomes infected and requires removal, a new device should not be implanted within 2 weeks to prevent seeding of the new device 4

Infection Prevention Strategies

For all cardiac devices, including MICRA, infection prevention remains important:

• Perioperative systemic antimicrobials
• Use of preoperative checklists
• Delay implantation in patients with active infection or fever for at least 24 hours
• Proper preoperative antiseptic preparation
• Meticulous sterile technique during implantation 1

The MICRA leadless pacemaker represents a significant advancement in reducing infection risk for patients requiring pacemaker therapy, particularly those with a history of device-related infections or at high risk for conventional pacemaker complications.