Contamination in the Cath Lab: Any Less Important Than in the OR?

When reading this very interesting report by Truscott regarding lint and particle contamination in the cath lab, I couldn’t help but flash back to scrubbing into my first cath lab cases in the late 1980’s after my formal training as a cardiac and vascular surgeon. The rigors of the OR sterile environment and the attitudes in the cath lab towards contamination were very different 15 years ago. Even today, there likely remains a general belief that the cath lab environment just doesn’t need to be as sterile as a formal operating theatre. This article nicely reviews several sources of potential contamination and should stimulate all of us to reassess our own lab’s anti-contamination protocols. It should also be a reminder to maintain diligence during each case to ensure we are doing everything possible to minimize any contamination risks to our patients. Questions central to this article and any discussion on cath lab contamination include: What are the true clinical and economic consequences of contamination in the cath lab and does contamination lead to infection? I suspect part of the less sterile attitude around the cath lab is because when a complication or contamination does occur (and they do occur), they are often not seen by the cath lab staff or even the interventionalist. The surgeon and operating room staff always see their complications and the site of pus running out of a wound or the surgical removal of an infected prosthesis and their complications is never a pretty sight to the surgeon or to the operating room staff (Figure 1A-C). The incidence and clinical and economic costs of surgical contamination and infection are well-known, but less characterized regarding the cath lab. The incidence of stent infection, easily the most frequently implanted cath lab device, is considered very low, therefore raising the issue of the importance of cath lab contamination. This article cites multiple examples of potential of both the infectious and noninfectious adverse clinical sequelae that could be secondary to lint and particle contamination in the cath lab. I found the 1997 referenced work by Whelan et al on the noninfectious foreign body contamination during pig stent implantation to be particularly intriguing. This report of a high incidence of glove powder (42%) and lint (12%) contamination in thrombosed stents certainly has far-reaching noninfectious clinical implications. The fact that foreign body inoculations may decrease the patient’s natural immune response to a known bacterial inoculum likely carries clinical infectious consequences. This may be especially true as many of our procedures become more complex and lengthy, and larger, more complex devices are implanted in the cath lab. The length of time of an operating room procedure has always been associated with an increased incidence of infection, but little mention of this is made for cath lab cases. Examples of cath lab cases that often take several hours include critical limb ischemia (CLI), electrophysiology (EP) cases, biventricular pacing automatic implantable cardiac defibrillators (AICDs) and the novel procedures for structural heart disease. Note that most of these implants are considerably larger foreign bodies than a 2.0 mm coronary stent. Let’s also remember that diabetics (DM) and chronic renal insufficiency patients have an impaired immune system, therefore are at a higher risk of infection, and that the incidence of DM varies between 20“30% in PCI patients to > 50-80% of CLI patients. The most important clinical issue I see today regarding contamination, foreign bodies, and/or infection in the cath lab setting is related to the use of vascular closure devices (VCD). If we think a minute particle of lint or glove powder is bad for the patients, why do we so frequently and without a thought to the long-term clinical sequela of VCDs, place these large foreign bodies both endo and extra luminal? Highly reactive sutures, 50-100 gm collagen wads, 3-4 mm metal staples, and endoluminal anchors likely elicit more contamination daily in our cath lab patients than does all the lint or glove powder in an entire year. Thankfully, the reported incidence of VCD infections is relatively rare, but when they do occur, they are catastrophic in nature and should be considered life-threatening, requiring a minimal of surgical vascular debridement and resection with autogeneous vein bypass (Figure 2A-C). One of my concerns is that we know very little about the long-term effects of these VCD large-particle contaminants on the vascular access site, or for that matter, any systemic inflammatory response to these foreign bodies. It is interesting to think out loud that stent outcomes in man could be related to lint contamination, as described by Whelan in pigs, and even more intriguing to know if the use of VCDs or even minor hematomas after manual compression could be associated with adverse long-term stent outcomes. For these reasons, I have rarely deployed a VCD in the past three years, and we now know that 1-year PCI mortalities and morbidities are associated with vascular access site complications and blood transfusions during PCI. The cath lab and our entire healthcare environment is much different today in 2006 than in the 1980’s, as are the cases performed. In the contemporary cath lab setting, clinical outcomes are tracked, economic costs are now equally as important, and litigation are but a few of the major differences. The basic anticontamination healthcare guidelines must be meticulously followed and more rigorous surgical attitudes should become more commonplace in the cath lab. I suspect some labs today still do not require masks and caps in all cases. One of the critical factors and lessons learned from the operating room applicable to the cath labs include the air filtration guidelines, and appropriate systems should be a requirement for newer labs and upgrades into older labs. I sense most labs treat the longer, more complex cases with large implants with a more heightened sense of sterility than the routine 15-20 minute PCI or renal stent case. This is good on the one hand, but in reality, all cases should be treated with exactly the same diligence to minimize all sources of contamination from lint in the belly button to lint in the groin. Tomorrow, after I turn on my disco music for our first case, I’ll make sure everyone in our lab wears caps and masks, and I’d suggest all the readers do the same (including the disco music).

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