TTHealthWatch is a weekly podcast from Texas Tech. In it, Elizabeth Tracey, director of electronic media for Johns Hopkins Medicine in Baltimore, and Rick Lange, MD, president of Texas Tech Health El Paso, look at the top medical stories of the week.
This week’s topics include continuing dual antiplatelet therapy after stenting, amyloid depletion in Alzheimer’s, infections in U.S. hospitals, and algorithms for diagnosing pulmonary embolism (PE) in people with cancer.
Program notes:
0:36 Infection rates in U.S. hospitals
1:36 Reviewed healthcare-associated infections in medical records
2:36 Reduction in Clostridioides difficile
3:36 Survey emerging bugs
4:00 Antiplatelet therapy after stent placement
5:04 Only 1.4% to 1.5%
6:00 Amyloid clearance and Alzheimer disease
7:00 Some brain regions responded and some did not
8:00 New agents better?
8:50 Detection of PE in people with cancer
10:00 Emergency departments assessed
11:00 Algorithm works well
11:46 End
Transcript:
Elizabeth: Good news about infections acquired in U.S. hospitals.
Rick: Do algorithms for diagnosing suspected pulmonary embolism work in those that have cancer?
Elizabeth: Does depleting amyloid help in Alzheimer’s disease?
Rick: And should we extend antiplatelet therapy in some individuals with coronary artery disease?
Elizabeth: That’s what we’re talking about this week on TTHealthWatch, your weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso. I’m Elizabeth Tracey, a Baltimore-based medical journalist.
Rick: And I’m Rick Lange, president of Texas Tech Health El Paso.
Elizabeth: Rick, we so very rarely have the opportunity to serve up something as really great news. And in this case, I’m feeling the need for great news, so I’d like to turn to the New England Journal of Medicine. A decline in healthcare-associated infections in U.S. hospitals in 2023 versus 2015.
We’ve talked many, many times about all of these infections that patients can acquire in the hospital. When they look at prevalence data, it’s reported that about one in 25 patients did have a healthcare-associated infection in 2011 compared with one in 31 in 2015. So they decided in 2023 to look at this again.
They have this emerging infections program, EIP sites. Ten of these programs recruited up to 25 hospitals each, and they selected a survey day between May 1 and Sept. 30, 2023. And they reviewed medical records of randomly selected patients to identify healthcare-associated infections. Of just shy of 14,000 patients in 218 hospitals, 2.6% had at least one healthcare-associated infection compared with 3.2% in 2015. About 60% of these healthcare-associated infections were not associated with devices or procedures. I was so uplifted by this. I thought we could start with it.
Rick: Yeah. And having a 27% less likelihood of having a healthcare-associated infection in 2023 compared to the 2011 survey is pretty remarkable. Although, when you put it in perspective, that still means the national burden exceeds over half a million infections.
The major contributor to the lower prevalence was a decrease in C. diff infections in 2023. And that’s due to increased testing, better antimicrobial stewardship, and infection control. But there was also a reduction in the prevalence of central catheter-associated bloodstream infections and catheter-associated urinary tract infections as well. So these are great success stories in ways we’ve tried to implement prevention strategies and changed the healthcare-associated infection definitions and diagnoses. So a lot of good things have happened over the last decade.
Elizabeth: And these either urinary or central catheter infections, so-called CAUTI [catheter-associated urinary tract infection] or CLABSI [central line-associated bloodstream infection], has declined quite a bit. They do point out in this study that the patient population was older, so therefore more susceptible to infection, and had longer hospital lengths of stay. So if we had added those things to our prediction, I suspect we would have thought they would have been the same or even gone up slightly.
Rick: Yep. You’re right. That makes it even more striking that we’ve had a decrease in the prevalence of infections. By looking at the type of infections and the different types of organisms involved, though, it’ll allow us in the subsequent decade to focus on these sites and on these organisms.
Elizabeth: Right. And really being quite happy about the reduction in C diff. Per your notion, 46% of the staph infections were methicillin-resistant. And of course, we are seeing other pathogens emerging that are not accounted for in this study.
Rick: Yep.
Elizabeth: Remaining in the New England Journal?
Rick: Yeah. So I’d tee this up as, do we need to continue antiplatelet therapy in people with coronary artery disease? And I’m going to be very specific. We’re talking about people that have had stents placed. They’re always put on at least two antiplatelet agents for a period of 3 to 12 months. Then in some individuals that have not just a single vessel, but multivessel coronary artery disease. And the question is, if we extend the antiplatelet therapy for another year, is there a benefit? You say, well, of course, there must be a benefit, but you have to balance that against the risk of bleeding.
What this study did was in 97 different centers in China, they took patients that had had multivessel coronary disease and had stenting, and were treated for 12 months with dual antiplatelet therapy. These patients had no ischemic events and no bleeding. And they said, OK, in these particular group of individuals, if you extended antiplatelet therapy, was there additional benefit?
What they discovered in the over 8,000 patients that were randomized is that there was a decrease in ischemic events, 5.8 versus 6.8. There had been an 18% reduction. Was there an increased bleeding risk? And the bleeding risk was the same. It’s about 1.4% or 1.5%.
Elizabeth: So this suggests a couple of things to me. One is, of course, this highly personalized approach that takes into account patient-specific factors with regard to either continuation or discontinuation, or initiation of treatment. I’m wondering how hard that’s going to be to implement because we keep on trying to move to these kind of standardized protocols.
Rick: This one’s really easy, Elizabeth. You’re deciding, do I continue dual or just go to aspirin? All you’re using are clinical events. If they’ve tolerated it for a year without any complications, you continue it. And these, by the way, are the two least expensive antiplatelet therapies, aspirin and clopidogrel.
By the way, when they did have an event, it wasn’t usually in the vessel that was stented. It was in one of the other vessels that was already diseased.
Elizabeth: Sounds like a change in practice, doesn’t it?
Rick: It does.
Elizabeth: Let us turn now to JAMA and let’s take a look at amyloid clearance in Alzheimer’s disease. And this is a single case report, one patient who had presented with Alzheimer’s disease when he was in his 50s, who had some PET scan evidence of Alzheimer’s disease. He also had a variant that’s called TREM2. He was going to receive aducanumab [Aduhelm] while participating in a randomized clinical trial. And they also chose 14 untreated controls who were matched by age or the presence of this same variant that are included in this analysis. This male carrier of this particular variant had received 30 doses of aducanumab over 4.5 years.
What they looked at, his neuropathologic evaluation at autopsy, PET scanning to look at amyloid and tau levels, and MRI to determine longitudinal changes in cortical thickness. It was 4 years after receiving his final dose of aducanumab that the patient died. They saw that there were brain regions that seemed to have responded pretty well to this removal of amyloid using this agent. And those were really superficial. They were at the gyral crests on the brain, while in the sulci there remained a pretty significant amount of amyloid.
Now, of course, we aren’t using this agent anymore. We have two different ones. And so now the question I think is, well, what happens with these other two agents?
Rick: Yeah. The story is interesting in that there is some amyloid protein that is “dissolved,” if you can call it that, or treated. It’s very heterogeneous. Some areas of the brain experienced it, others that didn’t. The ones that did have decreased amyloid had decreased tau protein. In addition to that, there was differential amyloid clearance. It looked like the areas of the brain in which there was amyloid clearance had less thinning. It seems to all correlate, but it’s just in a single patient.
It does, however, bring home the point that it’s not homogeneous. There are other agents that we also have. And the question is, do they achieve a better amyloid clearance and is it more homogeneous? We just don’t know.
Elizabeth: I think it is interesting, though, that we do see that there’s clearance. The authors suggest that it may be that the clearance is actually manifest in the pial layer, and that the vascularization that’s in there allows that to take place. The fact that the stuff remains in the sulci could be because it’s not getting that same density of CSF [cerebrospinal fluid] or whatever.
Rick: Yeah. And this is an antibody. So the antibody has to get from the injection into the central nervous system, specifically to the areas of the brain where the amyloid protein is. So you’re right. This is a big protein. So if it can’t make it into those certain areas, then it can’t dissolve the amyloid, and you don’t see the effects. Still more work to be done.
Elizabeth: Let’s turn to your second one, also in JAMA.
Rick: Many of our listeners may not know that for people that have cancer, their risk of having venous thromboembolism — deep vein thrombosis or pulmonary embolism — is estimated to be 11 times higher than the general population. Now, the absolute risk is about 1.5%, but still a 10- or 11-fold increased risk is substantial.
The diagnostic standard for establishing acute pulmonary embolism is to do a computed tomographic pulmonary angiogram, a CTPA, CAT scan, essentially. They’re not routinely available. They’re costly. They expose people to radiation. And so, although that’s the diagnostic test, what you’d like to be able to do is only submit individuals that are at high risk.
Typically, we have algorithms for deciding who those people are. It asks three simple questions. Does the person have signs of a deep vein thrombosis? Do they have hemoptysis, that is, a cough with bleeding? And third is, is pulmonary embolism the most likely diagnosis in this individual? Based upon that, if those answers are yes, then they’ll do a D-dimer adjusted based upon what the age is. And the question is, OK, does it work in individuals that have cancer as well?
To address that, these investigators in emergency departments or medical units in 21 hospitals in the Netherlands, Italy, Switzerland, Belgium, France, and Spain were randomized to just use the YEARS algorithm and only do a CAT scan in individuals that had a positive finding with the algorithm, or a CT scan in everybody.
Was there evidence of a symptomatic venous thromboembolism or possible PE-related death within 90 days? If they just apply the algorithm, it is about 15% of people had a pulmonary embolism diagnosed at baseline. The number was about the same in those individuals that had a CT angiogram just routinely.
Was there any difference with regard to death over the next 6 months? There really wasn’t. But by using the algorithm, they were able to reduce the CT scanning by about 20%. So using this algorithm is effective. There’s no increased risk of suffering a significant complication compared to doing a CT angiogram in everybody. It saves the cost and the time associated with about a fifth of the CT angiograms. So this is good news.
Elizabeth: It is good news. And it’s also going to be practice-changing, I think, and a lot easier to apply the algorithm versus scheduling the patient for CT and getting up to the suite to have the imaging done.
Rick: Yeah. A very well done study.
Elizabeth: So I misspoke, I think, at the beginning when we started to record it. I said we so rarely get to offer good news. We’ve actually offered quite a lot of good news today, and I like that a lot.
So on that note, that’s a look at this week’s medical headlines from Texas Tech. I’m Elizabeth Tracey.
Rick: And I’m Rick Lange. Y’all listen up and make healthy choices.
