Some infections associated with cardiac implantable electronic devices (CIEDs) are manageable and don't much affect clinical outcomes. Others, at the opposite side of the risk continuum, may raise mortality many times over.
Where a CIED infection resides on that scale may partly depend on whether it becomes apparent sooner vs later after device implantation, a new study suggests.
Although 12-month mortality went up in patients with "delayed" infections, that is, those emerging later than 3 months after CIED implantation, the risk also depended on whether the infection had spread beyond the pulse-generator pocket to the bloodstream.
As a result, and perhaps not surprisingly, the highest observed mortality was for delayed infections that were systemic compared with no CIED infection.
But unexpectedly, mortality was also high — raised more than three and a half times — for such infections that were delayed but "localized" to the pocket, in the analysis based on patients in the randomized PADIT trial.
Systemic CIED infections, whether early or delayed, presented greater risk than localized infections in the analysis. Mortality wasn't raised at all for appropriately managed early, localized infections. All that "makes intuitive sense" and reflects the literature, Hui-Chen Han, MBBS, PhD, told theheart.org | Medscape Cardiology.
But "our relatively big novel finding" was that the mortality risk from late-emerging CIED infections localized to the pocket was also "actually quite bad," said Han, Victorian Heart Institute, Monash University, Victoria, Australia.
The secondary analysis of PADIT, which had compared preventive antibiotic regimens in more than 19,000 patients receiving CIEDs at 28 centers in Canada, was published April 5 in JAMA Cardiology, with Han as lead author. It's based on the 177 PADIT patients who developed CIED infections within 1 year, for a rate of 0.9%.
Given the new findings, Han said, "as physicians, we may want to be a bit more vigilant during the first 12 months or so" after CIED implantation.
Typically, patients might come in for a follow-up evaluation 2 to 4 weeks after the procedure, and then not be seen again for perhaps another 12 months, he observed. Instead, he proposed, "we should be trying to so see our patients every 3 months for the first 12 months" to monitor more closely for any infection.
"We may also need to educate patients more about signs of infection to watch out for," he added. Part of that might be "repeated messaging" during the more frequent follow-ups. Each time, for example, "I might say to them, if there's redness, if there's tenderness in the scar, you'd need to contact us as soon as possible."
As the report notes, most cases emerged within the first few months after CIED implantation. The cumulative rates were 0.6% at 3 months, 0.7% at 6 months, and 0.9% at 12 months. The adjusted hazard ratio (aHR) for all-cause mortality associated with any infection was 2.21 (95% confidence interval [CI], 1.43 - 3.42; P < .001).
Infections were categorized as localized (n = 109), that is, in skin or subcutaneous or limited to the pocket; or systemic (n = 68), defined as bacteremia or endocarditis.
They were also defined by time of onset: early (n = 119), arising within 3 months of implantation, or delayed (n = 58), occurring 3 to 12 months after the procedure.
Twelve-month mortality was similar for patients with early localized infections and those without CIED infections. But the mortality aHR for those with delayed localized infections, compared with no infection, was more than tripled, at 3.57 (95% CI, 1.33 - 9.57; P = .01).
It rose nearly as high for those with early systemic infections, 2.88 (95% CI, 1.48 - 5.61; P = .002). And it shot even higher for patients with delayed systemic infections, reaching 9.30 (95% CI, 3.82 - 22.65; P < .001).
"No one's really looked before at how the timing of CIED infection affects patient outcomes," Han said. "We've generated a few potential ideas, but certainly nothing concrete." Future studies, therefore, should look at "how it affects outcomes and why it affects outcomes."
JAMA Cardiology. Published online April 5, 2023. Full Text
Han declared no relevant financial relationships. Disclosures for the other authors are in the report.
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Cite this: Mortality Climbs When CIED Infections Are 'Delayed' After Implant - Medscape - Apr 12, 2023.