WRAP IT: Novel Antibacterial ‘Envelope’ Reduces Rate of Infections From Implanted Cardiac Devices

NEW ORLEANS, LA—Adjunctive use of a fully-absorbable mesh envelope that elutes antimicrobials may be an important tool in reducing infection risk in patients who receive cardiac implantable electronic devices (CIEDs), the WRAP IT study suggests.

“The study provides comprehensive data on CIED infection and strong evidence for the use of the envelope in this patient population,” said study presenter Khaldoun G. Tarakji, MD (Cleveland Clinic Heart and Vascular Institute, Ohio).

Presenting the late-breaking WRAP IT study results here at the American College of Cardiology 2019 Scientific Session, Tarakji reported that major device-related infections that required removal, pocket revision, long-term antibiotic therapy, or resulted in death within a year occurred in 0.7% of the group that received the envelope (TYRX, Medtronic) in addition to standard anti-infection strategies and in 1.2% of a the control group who received standard preoperative antibiotics only (HR 0.60; 95% CI 0.36-0.98).

Patients were considered at increased risk of infection because they were undergoing CIED generator replacement or a system upgrade with or without new leads, CIED pocket or lead revision, or a first cardiac resynchronization therapy defibrillator (CRT-D).

The study was simultaneously published online ahead of print in the New England Journal of Medicine.

Safety and Efficacy Endpoints Met

WRAP IT enrolled 6,983 patients from 181 centers in North America, Europe, Asia, and South America who were followed for a mean of over 20 months. Both randomized groups had similar characteristics, with the exception of more use of immunosuppressive therapy in the control group.

Procedure times were not significantly longer in the group that received the envelope despite the need for a slightly larger pocket to accommodate it. In addition to the lower rate of major infections, the envelope group also had about a 60% lower rate of major pocket infections compared with the control group (0.4% vs 1.0%; P < 0.01). The safety endpoint was met, with no increased infections in the envelope group vs control (6.0% vs 6.9%; P < 0.001). No patients developed allergic or other complications due to the envelope materials.

Over a mean follow-up of 20.7 months, the event rate of major infections was lower in the envelope group at 1.3% vs 1.9% in the control group (HR 0.63; 95% CI 0.40-0.98). Combined major and minor infections also were less frequent, occurring in 1.5% of the envelope group and in 2.2% of the control group (HR 0.67; 95% CI 0.47-0.96).

In analysis stratified by device type, the benefit of the envelope over the control strategy in preventing major infections at 1 year was more pronounced in patients with high-power devices than in those with low-power devices (HR 0.51; 95% CI 0.29-0.90 vs HR 1.02; 95% CI 0.36-2.92).

Costs and Other Considerations

The antimicrobial envelope slowly releases rifampin and minocycline over a period of 7 days and is fully absorbed by 8 to 9 weeks after implantation. According to Tarakji, the envelope is available in two sizes—a small size for pacemakers and a larger size for defibrillators.

In a press conference, Dhanunjaya Lakkireddy, MD (University of Missouri, Columbia), noted that the overall incidence of CIED infections has been on the decline in recent years. Still, “when an infection happens it’s devastating to the patient, but it also poses an economic burden,” he pointed out. The approximate cost of the envelope is $1,000 per patient, which Tarakji acknowledged is “not cheap,” prompting Lakkireddy to wonder if the cost is justified, or if there might not be a cheaper way of recreating its effect.

While cost-effectiveness is “a healthy discussion to have,” Tarakji said, the cost of the envelope must be weighed against the cost of infections, especially those that prompt removal of the device, treatment, and implantation of another device to replace it. Data in this regard are lacking, he noted, adding that there may be some factors relating to the cost of infection “that you’re not going to be able to measure with a dollar amount.” One example that he related is the potential loss of the ability to access the same vein for device reimplantation after removal for an infection.

Tarakji said a planned cost-effectiveness analysis of WRAP IT is underway and should be available later this year.