Simple score is based on PADIT trial
SAN FRANCISCO -- An infection risk score for cardiac implanted electronic devices developed from the PADIT trial could streamline shared decision-making and allocation of antibacterial envelopes, researchers said.
Analysis of the large trial, which last year showed more aggressive antibiotic use around implantation wasn't better, generated the PADIT score:
- Prior procedures (1 point for one prior procedure, 4 points for two or more)
- Age (1 point for age 60 to 69 or 2 points before age 60)
- Depressed renal function (1 point for estimated glomerular filtration rate less than 30 mL/min)
- Immune compromise (3 points)
- Type of procedure (2 points for ICD, 4 points for CRT, and 5 points for revision or upgrade)
Internal validation of the score yielded a C-statistic of 0.704 after correction for optimism, David Birnie, MD, of the University of Ottawa Heart Institute in Ontario, reported at the Heart Rhythm Society(HRS) meeting.
That's on par with widely used prediction scores like CHADS2VASc Score (0.606) and the Framingham Risk score (0.763), Birnie pointed out.
HRS session study discussant Maria Birgersdotter-Green, MD, of the University of California San Diego, called the risk predictor "absolutely" clinically relevant, even though there have been others before.
"Risk scores in this case can be helpful. I don't love risk scores, in fact, I don't like them at all because I do sometimes think they take away from independent thinking and sometimes we may be stating the obvious in numbers that may not be needed. But it's not bad to have at hand when you have the discussions with patients."
That's especially true on the heals of the WRAP-IT trial showing reduced infections when using the Tyrx antibacterial envelope for cardiac devices, she noted. "Perhaps this risk score will be applicable in a patient population where the number needed to treat in the WRAP-IT study was quite high and the price was equally high."
The primary outcome of hospitalization attributed to device infection -- whether from pocket infection, sepsis, or endocarditis, as documented in the clinical record -- occurred in less than 1.0% of people with a score of ≤4, but 1.9% in those with a score of 6 and 3.4% among those with a score of ≥7.
Birnie noted at the late-breaking clinical trial session that his center decided to use ≥6 as a threshold to use more aggressive antibiotics, and if the hospital will pay for it, the Tyrx envelope.
It's "quite easy" to get to a score of 7, he added. An 85-year-old reaching elective replacement time for his second primary prevention ICD who has renal dysfunction has a PADIT infection risk score of 7, for example.
Beyond just infection-risk reducing measures, the score could even inform whether to replace the generator at all, or just deactivate it without opening the pocket, added HRS press conference moderator Fred Kusumoto, MD, of the Mayo Clinic in Jacksonville, Florida.
"Maybe just leaving that device, pacemaker, or ICD in David [Birnie's] example for primary prevention, in situ is a way better solution for someone who is older and you're very worried about the risks and consequence of infection," he said.
"I do think that will change practice, because at this point in time, many physicians might just pull out the generator, exposing the patient to the risk of the infection, and then sew up and not put a new generator in. I see that as actually a worse possibility," Kusumoto added.
Birnie cautioned that the trial didn't have data on oral anticoagulation or antiplatelet drug use, which are known to increase pocket hematoma risk that in turn affect infection risk.
Birnie disclosed no relevant relationships with industry.
Heart Rhythm Society
Source Reference: Birnie DH, et al "Update From The Prevention Of Arrhythmia Device Infection Trial (padit); Development Of The Padit Infection Risk Score" HRS 2019; Abstract LBCT02-01.
Read the original article on Medpage Today: Cardiac Device Infection Gets a Risk Predictor