Treating Carotid Stenosis; Social Factors in USPSTF Guidance
TTHealthWatch is a weekly podcast from Texas Tech. In it, Elizabeth Tracey, director of electronic media for Johns Hopkins Medicine, 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 the value of finding atrial fibrillation in those at risk for stroke, social factors in USPSTF recommendations, giving a flu shot to those who’ve had an MI, and treating carotid stenosis.
0:54 Stroke prevention via treating carotid stenosis
1:48 All had good medical therapy afterward
2:50 Avoid atherosclerosis in carotids
3:32 Flu vaccine after MI
4:30 All cause death lower in flu vaccine group
5:31 Reduces future heart attacks
6:32 Discern the mechanism?
7:00 Atrial fibrillation identification and stroke
8:00 Implantable loop recorder identified
9:00 Those with high blood pressure
9:15 USPSTF on social factors impacting health
10:15 Came down to five questions to examine
11:20 Very start of the social risk factors path
Elizabeth Tracey: Should you get a flu vaccine if you’ve had a heart attack?
Rick Lange, MD: Comparing stenting with surgery for people who have blockage in their carotid artery.
Elizabeth: What is the impact of social factors relative to health in the USPSTF statements?
Rick: Does continuously screening for irregular heart rhythms help prevent stroke?
Elizabeth: That’s what we’re talking about this week on TT HealthWatch, your weekly look at the medical headlines from Texas Tech University Health Sciences Centre in El Paso. I’m Elizabeth Tracey, a Baltimore-based medical journalist.
Rick: I’m Rick Lange, president of Texas Tech University Health Sciences Centre in El Paso where I’m also dean of the Paul L. Foster School of Medicine.
Elizabeth: Rick, let’s mention that we’ve chosen these heart ones because, of course, the European cardiology meeting has just concluded, so we have gotten some really interesting material out of that. You chose two of these studies. I’m going to let you start with the one you like best.
Rick: They are both good, but let’s start with the one that looks at stroke prevention. We know that people who have never had a stroke before, but have a severe blockage in their carotid artery, that’s the artery that supplies blood to the head — now when I say severe, a 75% to 99% blockage — we know that that increases their risk of having stroke. Previous studies have shown that if you have surgery, that’s called a carotid endarterectomy, where they go in and actually peel that blockage out of the artery, you can help prevent strokes in those individuals.
But we have another technique called stenting that actually props the blood vessel open. Are these two equivalent? There have been previous studies that have looked at this, but this is actually a large, very well done study in over 3,600 patients in 130 different centers around the world. They were randomized to either having stenting or carotid surgery. They were asymptomatic, but they have a severe blockage.
All these people had good follow-up and they also had good medical therapy afterwards. They were followed for a mean of five years. Overall, 1% of individuals with either procedure had a disabling stroke or death related to the procedure — 2% had what was called a non-disabling stroke related to the procedure. Serious complications were uncommon after either procedure, they were similar after either procedure, and the long-term results of these carotid artery procedures appear to be comparable.
Elizabeth: Let’s just remind folks that these are in The Lancet. What it sounds like to me is that probably if you get the opportunity to choose, which maybe you can and maybe you can’t, that the thing to do might be to choose a center or choose the procedure where that’s what they do all the time since we know from other procedures that that’s a good idea.
Rick: You’re right. In many of these places, by the way, they were equally talented at doing either of these procedures.
Elizabeth: Clearly, avoiding this outcome of disabling stroke is a good idea. Talk to me a little bit about prevention. What about trying to avoid atherosclerosis in their carotid arteries at the get-go?
Rick: Well, a great question Elizabeth and we talked about good medical therapy. That’s primary prevention, preventing someone from having a stroke, and making sure that someone’s blood pressure is well controlled because that contributes to blockage in the artery, their diabetes is controlled, their smoking cessation, people on a statin medication to lower cholesterol, and oftentimes on an antiplatelet agent like aspirin.
Elizabeth: Finally, let’s just note that this is something that’s routinely screened for with really very-low tech. “Hey, let’s put the stethoscope on your neck and see what we hear.”
Rick: For individuals that appear to have a blockage, then doing a sonogram can actually provide insight into how severely blocked a carotid artery is or is not.
Elizabeth: Let’s turn from here to Circulation. Again, a heart-related study and something that I find really tantalizing and we have talked about before. This study is actually a randomized control trial just to see if giving people an inactivated influenza vaccine after they have had an MI, a myocardial infarction, or in a very small number of patients who had high-risk stable coronary heart disease, would prevent at 12 months a composite of all-cause death, a second MI, or stent thrombosis.
This is a really interesting thing because previous studies have suggested that providing an influenza vaccine to these folks would be a good idea. In this case, they took a look between October 1, 2016 and March 1, 2020 — 2,571 participants in 30 centers across eight countries, 1,290 assigned to the flu vaccine and 1,281 to the placebo.
All-cause death, I’m just going to cite that one, 2.9% in the group that got the flu vaccine. Almost twice as much, almost 5%, in the placebo group. Also increased rates of cardiovascular death and of MI, but just slightly more in the placebo group.
This is pretty persuasive that we ought to be administering an influenza vaccine and, of course, they also adjusted this seasonally for when the influenza virus would actually be circulating in these various countries. It still sounds like giving that when somebody is hospitalized is probably a good idea.
Rick: We have known that in people that have heart disease, influenza vaccination can prevent death and cardiovascular death. This is the first time where the influenza vaccine was actually given during a hospitalization. These are people that were having an acute heart attack. About three-fourths of them had a stent put in, a fourth of them were treated medically, and before they left the hospital they gave the influenza vaccine. It clearly reduces death and cardiovascular death by about 40% and future heart attacks by 14% with no additional risk at all. I think this is really good news. It ought to be a part of our standard armamentarium.
Now, having said that, these were individuals that had not had influenza vaccine in the previous 12 months and most of these individuals were ones that weren’t planning on getting it in the future.
Elizabeth: I find this really interesting from a biological plausibility standpoint. My question is, is there some hypercoagulopathy that’s represented by influenza infection, much like what we are seeing in many people with COVID these days? Could preventing that particular aspect of influenza infection be the mechanism by which this is working?
Rick: There are two possible mechanisms. One is it prevents an infection — that is influenza — that predisposes to inflammation and/or clotting events. The second is that maybe the shot itself is anti-inflammatory because we know that this causes an increase in the immune response and it decreases cytokines as well.
Elizabeth: Something I think, though, should clearly be followed up in an attempt to discern the mechanism. Because if it turns out that administering a vaccine reduces inflammation, and therefore these other dire consequences, we maybe ought to be doing that for many more patients other than those with just MI.
Rick: Your point is very well taken.
Elizabeth: Okay. Let’s go back to The Lancet.
Rick: I tee this up as just continuously looking for an irregular heart rhythm to prevent stroke. I am talking specifically about a rhythm called atrial fibrillation where the upper chamber of the heart doesn’t contract synchronously with the lower chamber. It just kind of quivers. We know that in individuals that have atrial fibrillation the risk of stroke is five times higher than in people that don’t have atrial fibrillation. About 20% of all strokes are linked to atrial fibrillation and we know those people should be on anticoagulants.
Now, let’s take a look at the general population. Should we just be screening for it because oftentimes we don’t find out about it until someone has already presented with a stroke.
This was a trial conducted at four centers in Denmark where they included individuals who never had atrial fibrillation, but they were at risk of it. They were older, age 70 to 90 years, and they had a risk factor for atrial fibrillation like high blood pressure, diabetes, previous stroke, or heart failure.
They randomized them to just usual care or having what’s called an implantable loop recorder. That’s a little device put underneath the skin that continuously monitors the heart rhythm.
When they looked at over 6,200 individuals that they had screened and they included 6,000 of them in the study, they found that using the implantable loop recorder increased the detection of atrial fibrillation threefold. Those that didn’t have it they detected in about 12%. Obviously, those people got put on anticoagulation, both groups. But the interesting thing is the individuals with the loop recorder and anticoagulation did not have a lower risk of stroke than those that were just managed routinely.
Elizabeth: We’ve talked about this actually before in a pair of studies that were in JAMA about these implantable loop recorders and should we actually be using them? Answer that question, Rick. What are you going to do in your patients whom you suspect of having atrial fibrillation?
Rick: What this study implies is not all atrial fibrillation is alike. We need to figure out which type of atrial fibrillation we need to detect and which we need to treat. It may have to do with a number of risk factors. For example, in this particular study, it looked like the people with the highest blood pressure and atrial fibrillation had the highest risk of stroke, and screening in them and giving them blood thinners may in fact have been helpful.
Now, by the way, you’re not terribly surprised that the people on anticoagulation had a slightly increased risk of bleeding because that’s one of the side effects from it.
Elizabeth: Finally, let’s turn to JAMA. This is a look at the USPSTF, the United States Preventive Services Task Force, behavior on the social determinants of health, if you will, and a brief that examines what’s known out there right now that’s going to help inform them going forward.
The first paper takes a look at the 85 USPSTF recommendation statements that are active as of December 2019 and to determine how these social risks were addressed in their clinical preventive services recommendations.
What they determined in their self-examination was that 57 of those 85 recommendations included some comment on social risks within that recommendation statement. They identify this as the benchmark going forward relative to incorporation of social risk factors. In the technical brief, what they looked at was a bunch of literature and 106 social risk factor intervention studies with almost 6 million individuals represented.
I think the thing that’s informative here was they came down to five questions that they really need to look at. What are the available multi-domain screening tools to identify social risk and what do they identify? Which ones have been evaluated? What are the effects of improvements? What are their perceived or potential challenges to implementation? What are the challenges of unintended consequences of screening and interventions for social risk factors?
What they ultimately came down to in toto, as far as my reading of this is concerned, is that many of these screening tools that they are talking about are going to add a rather significant burden to primary care practices, who are the ones who are called upon to implement USPSTF recommendations. What are you going to do? Hire somebody who is just going to implement all of these screening tools.
There are a lot of screening tools. I think they also admit that there is not a lot of evidence yet for which one of these things is the best or if more than one of them is the best. We are starting on this issue of social risk factors and their impact on health, but I don’t think we’re there yet.
Rick: We are just at the very start of this path. Specifically, the social risk factors that they looked at influenced health outcomes are housing instability, food insecurity, transportation difficulties, utility needs, interpersonal safety, education, and financial strain. You don’t have to think very hard before you realize that these things do affect health outcomes.
But as you said, the person who oftentimes needs to screen for these, the primary care physician, is not the person that can change those things. Then, by the way, how do you measure the health outcomes to find out whether your intervention has been successful or not? That’s why I say we’re really at the very beginning.
Elizabeth: They also admit that the racial and ethnic groups are sometimes all the rest of these things, a proxy for that.
Rick: Right. Another thing they highlighted is many of the studies done are just observational studies, but no comparison. You really don’t know whether what they are doing is actually improving health outcomes or not. Those of us delivering healthcare realize how important addressing these are to resolving the healthcare disparities we see across the United States.
Elizabeth: No more profoundly than we see them today. On that note, that’s a look at this week’s medical headlines from Texas Tech. I am Elizabeth Tracey.
Rick: I am Rick Lange. Y’all listen up and make healthy choices.
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