Can Eyes Predict CVD Mortality?; ICUs in the ED
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 the Texas Tech University Health Sciences Center in El Paso, look at the top medical stories of the week.
This week’s topics include eye scans to predict cardiovascular disease (CVD) mortality, preventing stroke in transcatheter aortic valve replacement (TAVR), should the newer diabetic medications be first line, and intensive care units (ICUs) in the emergency department (ED).
Program notes:
0:40 Devices to prevent strokes during TAVR
1:40 Approved on basis of debris presence
2:40 Overall risk of stroke is low
3:20 ICU care in the ED
4:20 Economic drivers?
5:20 ICU doc floors away
6:20 Also board certified in critical care medicine
6:40 First-line therapy for type 2 diabetes
7:40 Benefits in mortality and other outcomes
8:40 In people without existing heart disease
9:12 AI look at the retina and prediction of mortality
10:12 Vascular photographs and AI interpretation
11:14 Offers no additional value
12:55 End
Transcript:
Elizabeth: Should we shift intensive care units to the ED?
Rick: Should the newer diabetic medications be first-line therapy?
Elizabeth: What can the eyes tell us about somebody’s cardiovascular disease risk?
Rick: And how effective are the devices we’re using to prevent strokes to someone that has a catheter-implanted valve?
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 University Health Sciences Center in El Paso and Dean of the Paul L. Foster School of Medicine.
Elizabeth: Rick, I’m going to let you choose. Where would you like to start?
Rick: Elizabeth, let’s talk about the thing I introduced as devices to prevent strokes during catheter placement of a heart valve. This comes from the New England Journal of Medicine and it’s based upon the fact that in 2017 the FDA approved a device — and I was part of this panel — that looked at the use of devices that are meant to prevent stroke.
When someone puts in a heart valve using a catheter that’s done through the femoral artery or through one of the arteries in the arm, it’s advanced over the present valve in the heart, the aortic valve that’s already diseased, and then that valve is inflated with a balloon. What it does is it pushes the new valve, pushes the old valve out of the way, and implants the new valve. When you do that you run the risk of having a stroke, and that stroke incidence in the early days was as high as 5% to 10%.
So they developed devices that are meant to sit just before the vessels that provide blood flow to the brain to catch any debris. In fact, if you take those devices out, you can see that there is in fact debris there. The FDA approved these devices based upon that without any data showing that they could prevent strokes. What this study tried to do was say, “Okay, let’s look at the final endpoint as, ‘Do these devices prevent stroke?'”
In this study they took 3,000 patients in North America, Europe, and Australia who were undergoing transcatheter aortic valve replacement. In half of them they used one of these devices — called a cerebral embolic protection device — and then they looked to see what percentage of individuals had stroke.
In fact, they could show that they caught the debris, but they didn’t show that they decreased the incidence of stroke or in a statistically significant way, even disabling strokes as well. The FDA is going to have to go back to the drawing board. In fact, many people across the U.S. weren’t convinced by the preexisting data, and these devices are only used in about 15% to 30% of patients right now.
Elizabeth: The question, of course, for me is, what’s the downside of using these things?
Rick: About one in a thousand patients will have vascular problems. The second thing is the increased cost; it increases the time as well for doing the procedure. But one of the reasons why it’s hard to show these devices provide any benefit is the overall risk of stroke was low. It was less than 3%.
Elizabeth: Would you say that the notion that they were going to be helpful was based on data from carotid endarterectomies?
Rick: No, it was based upon the fact that you could see debris that was caught. There were some people on the panel that thought, “Gosh, this is better than nothing, and surely because we’re catching debris it must be effective.” But there was a group of us that thought, “No, they need to show that it actually does what it’s supposed to do.” I think this study provides the evidence, looking at whether it’s effective or not, and it doesn’t appear to be.
Elizabeth: It’s always good to prove those kinds of things. Speaking of cost-effectiveness then, let’s turn to JAMA Network Open. This is interesting to me because, as you’re well aware, Rick, I spend a lot of time in the medical intensive care unit at Hopkins, so I’m very interested in that level of care.
This is a study that’s looking at cost-effectiveness of an emergency department-based intensive care unit. The rationale behind this is that many people when they present to the ED, even if they’re critically ill, may end up boarding in the ED for sometimes really prolonged periods of time, and it has a very deleterious impact on the quality of their care as well as their outcomes.
And so, at the University of Michigan, they opened up an ED-associated ICU and they did that in February of 2015. What they did in this study was actually show that, gosh, is it cost-effective. They had a cohort that was previous to the opening of their ED-based ICU and then a cohort that was post-ICU. They looked at all of these different basically economic drivers relative to, “Does it make sense to have this ICU there?”
A lot of people here: 119,000 in the post-cohort and 115,000 in the pre-cohort. What they found was that after they opened up their ICU in the ED, more patients required intensive respiratory support and there was more vasopressor use. However, at the end of the day, when you looked at inflation-adjusted total direct cost per ED encounter, it was essentially the same. They have really shown that there is no real downside and there is significant upside to having an ICU associated with the ED.
Rick: Right. Elizabeth, just to make sure that for our listeners, we’re not talking about closing your ICU, then moving it to the emergency department. We’re talking about those patients that have been seen in the emergency department. They decide they are going to admit them to an ICU, but there are no ICU beds available. In that case, those patients sit in the emergency department. The quandary is, well, who takes care of them? Does the emergency doctor take care of them? Well, they are busy. The ICU doctor is usually floors away. They shouldn’t be taking care of them.
What they did was they established a separate 9-bed ICU. It has its own staffing. It has its own attending physician there 24 hours. They use nurse practitioners, residents, fellows, their own nurses, and everything. As you mentioned, it shows that it costs no more to do that than running patients in the regular ICU.
Now, not every hospital is going to be able to do this, Elizabeth. It requires its own special space and complete new staffing. But as you said, in the end it doesn’t cost any more than the standard ICU. Now, what’s not included in this cost is the amount of money it takes to build this thing, but once that’s done, the overall care cost is the same.
Elizabeth: I think the editorialist brings up a really excellent point, which is that many people who work in an ED already have this level of skill that enables them to care for people who are critically ill. This is a furthering of their ability and expansion of their skill set, and they liked it.
Rick: These were ED physicians who were also board-certified in critical care medicine. By the way, that’s just a recent event. The nice thing about the University of Michigan is to have access to those individuals, but a lot of hospitals don’t.
Elizabeth: I think anybody who gets to not really just be boarded in the ED, that’s always a good outcome.
Rick: Yeah.
Elizabeth: Let’s turn to this issue in Annals of Internal Medicine about first-line therapy for type 2 diabetes and these newer agents.
Rick: Our listeners won’t be surprised that type 2 diabetes affects more than 30 million adults in the U.S. and it costs about $327 billion annually to care for these individuals. A lot of that cost is due to the fact that we have newer medications that are effective. The two ones I’d like to talk about are what’s called sodium-glucose cotransporter-2, or SGLT2 inhibitors, and glucagon-like peptide-1 (GLP-1) receptor agonists.
Large randomized trials have shown that these medications can reduce cardiovascular disease and microvascular disease, improve mortality, and also improve hemoglobin A1c. The first-line therapy is currently metformin. What these authors attempted to do is say, “Is it reasonable to make these newer medications first-line therapy?” I say “reasonable” — it has to be cost-effective.
They developed a model based upon what the costs were of these medications. They used Medicare costs across the country. They looked at what the benefits were in terms of mortality, lower lifetime rates of congestive heart failure, heart disease, heart attacks, and stroke. What they found was these first-line SGLT2 inhibitors cost $43,000 more and added only 1.8 quality-adjusted months. That’s versus metformin. By the way, it was more expensive than the GLP-1.
Then they came back and said, “How much would these medications need to be decreased in terms of their costs to make these effective first-line therapies?” The SGLT inhibitors would have to come down about 70% and the GLP-1 inhibitors would need to come down about 90%. It’s not reasonable to think that these can be first-line drugs unless their cost goes down substantially.
Elizabeth: I’m wondering about this, though, among those people. We know that with all the heart issues, that these are helpful with that. I’m wondering, is there a subpopulation in whom these might be considered as first-line therapy?
Rick: Yeah. Elizabeth, your point is well taken because what I have addressed is, should these be first-line therapies in people without underlying heart disease? Should they be used in people with existing heart disease? The answer to that is yes. Even though they are more expensive, their benefit in that particular population is higher than it is in the general population.
Elizabeth: Right. Of course, I just have to remind you that we know that our first-line therapy is really lifestyle modification, including diet, exercise, and weight loss.
Rick: Point well taken. We’re talking about first-line, pharmacologic therapy. But lifestyle therapy, that’s where the true treatment begins.
Elizabeth: Exactly. Finally, then let’s turn to the BMJ’s British Journal of Ophthalmology. We disagreed before we started to record on whether we liked this study, and I’ll tell you why I found it interesting even though its results are not all that persuasive.
This is using an AI-enabled retinal vasculometry for prediction of circulatory mortality, MI, and stroke. This study that we are hearing so much about that’s yielding all of this data right now, the UK Biobank Study, they used AI-enabled retinal vessel image analysis from folks who were in that study. Then they also had another population of 7400+ European Prospective Investigation into Cancer — so-called EPIC-Norfolk — participants.
They took a look at retinal, arteriolar, and venular width, tortuosity, and area in these basically what amount of photographs that they take of this. Then they use this AI model in order to say, does this tell us anything about circulatory mortality, incident stroke, and MI?
It really didn’t improve a whole lot of that, although it was no worse than what it is that we’re doing right now. I have the opinion that this retinal vasculometry is just really interesting and offers a snapshot into the health of somebody’s circulatory system in a noninvasive way that I don’t think we really have that right now.
Rick: What you’re talking about is taking a picture of the back of somebody’s eye, submitting it to a computer and letting them measure the width of the blood vessels, the arteries and veins, and also how tortuous they are. These are microvascular vessels and it’s one of the few places you can see them.
But what they were trying to do is to say, “Gosh, we’d like to see whether this predicts cardiovascular mortality, heart attack, and stroke.” Those are macrovascular. Those are big-vessel events. What they were trying to do is use this as a predictive model. Well, we have so many other things that we know are predictive: blood pressure, do you have diabetes, and what’s your hemoglobin A1C? This doesn’t offer any additional value over those. I’m glad they did this study to see whether it offered additional value, but it doesn’t.
Elizabeth: I think that’s all absolutely true and, as I suggested, I think that we don’t have any way of really assessing someone’s vascular health in a visual way. This potentially offers that and maybe it’s going to be serial retinal images that take a look at that over time. I would think that if vessel tortuosity increased or what they saw here — that the arterial side was getting smaller and the venule side was getting more distended — that that could be an indication that there is something we really need to pay attention to.
Rick: I agree with you. It does look at microvascular health. Regardless of what your eye looks like, you’re going to try to get the blood pressure in the right range and you’re going to get the lipids down. Because this doesn’t add anything to the other predictive risk factors we have, I’m not sure that you’re going to be able to do anything else with that information.
Elizabeth: We agree to disagree, and perhaps are going to see more about this particular strategy. I just want to know one other thing about their study populations. Their BMIs in both of them were right around 28. Did they select those folks for not being more obese?
Rick: This wasn’t the primary focus of the studies. These were people that were in United K Biobank and also some that were in a prospective cancer study, so a general population not selected for anything in particular.
Elizabeth: But thinner than Americans are in general. 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.
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