Sonographer here. The threshold for stenting or endart is typically a stenosis of greater than 70%. Up until that point medical therapy and lifestyle changes are recommended. If a side is occluded the pt needs patent vertebral arts and a complete circle of Willis to encourage vascular flow through out the brain, otherwise infarction will occur. Pts are monitored for carotid art disease once it is found to ensure treatment is effective.
Stroke rates are low. But CAS (in experienced high volume centers) does seem to provide a real benefit, with a decent NNT, albeit statistically fragile.
I wonder about ASA use in IMM arm. Text mentioned antiplatelet use was comparable in all treatment arms, but details are in supplement which I haven’t looked at yet.
I’m curious about the poor target attainment for risk factor control in IMM arm. On one hand, there’s more bang to be had there. OTOH, if a diligent research team could not cajole people to take their meds sufficiently, that bodes less well in a real world setting. But I’d also like to see attained doses of various therapies.
In the end, it requires a discussion with the patient. Starting from asymptomatic state, are they willing to accept a real upfront stroke risk with CAS, in exchange for a real downstream benefit of reduced stroke?
155 centers, 600 patients in each intervention arm( CEA and CAS) average of 4 interventions per procedure per center.
All intervention patients received at least ASA long term, not clear that IMM patients had the same anti-platelet treatment.
20 % of the IMM only patients had either CES or CEA during the follow up period, listed as due to symptoms, progression of stenosis or patient preference. Reviewers were blinded, patients and clinicians were not.
Two separate IMM only control groups had dissimilar event rates that are not addressed, if control group rate was the same in each intervention arm the advantage of stenting would be minimal.
The immediate consequences of intervention of either type produced 17 adverse outcomes in asymptomatic patients.
No cost comparison offered or attempted. What is the optimal use of resources for society vs individual?
It's nice to see my biases confirmed. One of the biggest issues that I see is case finding in asymptomatic patient that go to screening clinics and expensive "life extension" centers that do Carotid ultrasound along with tests such as total body MRI. It should be pointed out that screening for asymptomatic carotid lesions has been discouraged for a long time but still gets done. Where it gets messier however is the patient with a lot of risk factors who might have had a symptomatic event. In my community endarterectomy is a very infrequent procedure so if I needed one I would like to have a surgeon who has a lot of experience
And of course, unsaid is in a midsize city that has a very good medical population because the spouses like to live here. I know someone who knows for a fact there's a wide variation in outcome with stenting. If I'm getting any procedure, I'm going to ask if they're enrolled in the registry and what their data is.
How were event rates so high? We consider these low risk lesions (1% event rates) but the trial showed 4 year event rates of 5.3-6% on medical therapy. Is that generalizable or was there some characteristic of the patient population that made them higher risk?
He didn’t write the risk of a stroke due to asymptomatic carotid stenosis was 1%, asymptomatic carotid stenosis cause 1% of all strokes from what he wrote.
There will be modest effect size(at most) in studies involving vascular issues where competing causes of disease are so prominent. They are isolating here the effect of intervening locally on a specific vascular territory when the macroscopic view tells you that the real issue is that the patient is generally at risk of any type of vascular insult. That is the power of focusing more on the medical intervention front where the goal is to intervene in a more comprehensive way.
Thank you for pointing this out - The medical machine is famous for doing unnecessary things for money, and older Americans are seemingly a huge pocket with Medicare.
Isn't there risk inherent in Any surgical procedure, aside from the obvious boondoggle of taxpayer funds and taking up space, time & manpower in medical facilities?
If anything, this is worse now, as hospitals got used to being filled to the brim during Covid, many are closing for various reasons, and my home, South FL is overrun with retirees on whom so many doctors do this crazy stuff.
Surgeons depend on what for their living? Surgery. So they're referred to a surgeon for Any asymptomatic issue. What do we think the surgeon will say, "Oh, no, this doesn't have a big benefit..." (To scheduling dept) "Incoming", and "Next!"
TCTMD has a balanced discussion on this but with a headline that reads
"Long-Awaited CREST-2 Results Bolster Stents for Asymptomatic Carotid Stenosis"
The 3.2% absolute difference in the rate of the primary outcome favoring intervention, resulting in a number needed to treat of 31 is impressive, however (even if fragile)
and raises the possibility that stenting might be useful.
The interventionalists will seize on this to promote carotid stenting. The TCTMD articles quotes one as saying
“In the neurovascular and neurointerventional community, we are excited and welcome these results as this is a big paradigm shift in evidence-based treatment of patients with asymptomatic carotid disease,” SVIN President Thanh Nguyen, MD (Boston Medical Center, MA), commented to TCTMD."
Now apply IMM to the real world and I think the bar to stenting lowers quite a bit. The signal for stenting was small but that was in patients selected to be highly motivated for IMM - hence agreeing to be in the study - who were no doubt hounded by coordinators to stay on track. Even so the adherence rates were not great - so what will they be in the real world?
If anything I think the study strongly points to stent - as IMM is not likely to be adhered to.
As in all things, judgement enters the picture. Smoking hypertensive patient with poor medical compliance? Stenting is potentially a better option. Retired engineer who brings charts of his BPs and pulse to visits, with a two page printed medical hx, who is hyper cholesterolemic and hypetensive? Medical therapy is likely appropriate.
Device/procedure vs medical management studies today are occasionally patient focused. Often, they are about the procedure (supported by a generous grant from ACME Medical Devices). They don’t LIE; they do, however cherry-pick, and at times make pronouncements about all patients in a study population, when only certain subgroups are truly appropriate. While the ads in the Journal of XYZ shout “ACME Device: Proven Statistically Superior to Medical Management”. Leading clinicians who are either too trusting, incurious, or predisposed to that option, to apply a broad brush in the clinic.
Judgement is challenging, and takes more time. Applying a broad brush is quick, and easy. Pharma and Device Inc count on clinicians to do the latter.
Let’s all do our best to disappoint them, shall we?
Yes, it's a Built-in supply of patients to be scared into stuff, or sold it on TV.
One of our residents watches the Hallmark channel (and they're by No means the only ones to do this) and nearly ALL the commercials are for a drug or a medical device or procedure. I'm not a fan of selling things to this captive audience. Can we just watch a feel-good movie and let the elderly woman rest without pointing out all the scary things she can be saved from by simply Finding a doctor willing to prescribe it? I don't doubt commissions are paid because I know a couple of ex drug reps who say they ARE paid (even if 'in-kind') to physicians, a huge conflict of interest.
Sonographer here. The threshold for stenting or endart is typically a stenosis of greater than 70%. Up until that point medical therapy and lifestyle changes are recommended. If a side is occluded the pt needs patent vertebral arts and a complete circle of Willis to encourage vascular flow through out the brain, otherwise infarction will occur. Pts are monitored for carotid art disease once it is found to ensure treatment is effective.
amen
This is a challenging one.
Stroke rates are low. But CAS (in experienced high volume centers) does seem to provide a real benefit, with a decent NNT, albeit statistically fragile.
I wonder about ASA use in IMM arm. Text mentioned antiplatelet use was comparable in all treatment arms, but details are in supplement which I haven’t looked at yet.
I’m curious about the poor target attainment for risk factor control in IMM arm. On one hand, there’s more bang to be had there. OTOH, if a diligent research team could not cajole people to take their meds sufficiently, that bodes less well in a real world setting. But I’d also like to see attained doses of various therapies.
In the end, it requires a discussion with the patient. Starting from asymptomatic state, are they willing to accept a real upfront stroke risk with CAS, in exchange for a real downstream benefit of reduced stroke?
Fantastic review! Great application of evidence-based principles! Appreciate the time and effort taken to put this post together. Thank you🙏
Observations from the study data:
155 centers, 600 patients in each intervention arm( CEA and CAS) average of 4 interventions per procedure per center.
All intervention patients received at least ASA long term, not clear that IMM patients had the same anti-platelet treatment.
20 % of the IMM only patients had either CES or CEA during the follow up period, listed as due to symptoms, progression of stenosis or patient preference. Reviewers were blinded, patients and clinicians were not.
Two separate IMM only control groups had dissimilar event rates that are not addressed, if control group rate was the same in each intervention arm the advantage of stenting would be minimal.
The immediate consequences of intervention of either type produced 17 adverse outcomes in asymptomatic patients.
No cost comparison offered or attempted. What is the optimal use of resources for society vs individual?
Great study. Questions remain.
It's nice to see my biases confirmed. One of the biggest issues that I see is case finding in asymptomatic patient that go to screening clinics and expensive "life extension" centers that do Carotid ultrasound along with tests such as total body MRI. It should be pointed out that screening for asymptomatic carotid lesions has been discouraged for a long time but still gets done. Where it gets messier however is the patient with a lot of risk factors who might have had a symptomatic event. In my community endarterectomy is a very infrequent procedure so if I needed one I would like to have a surgeon who has a lot of experience
And of course, unsaid is in a midsize city that has a very good medical population because the spouses like to live here. I know someone who knows for a fact there's a wide variation in outcome with stenting. If I'm getting any procedure, I'm going to ask if they're enrolled in the registry and what their data is.
How were event rates so high? We consider these low risk lesions (1% event rates) but the trial showed 4 year event rates of 5.3-6% on medical therapy. Is that generalizable or was there some characteristic of the patient population that made them higher risk?
He didn’t write the risk of a stroke due to asymptomatic carotid stenosis was 1%, asymptomatic carotid stenosis cause 1% of all strokes from what he wrote.
There will be modest effect size(at most) in studies involving vascular issues where competing causes of disease are so prominent. They are isolating here the effect of intervening locally on a specific vascular territory when the macroscopic view tells you that the real issue is that the patient is generally at risk of any type of vascular insult. That is the power of focusing more on the medical intervention front where the goal is to intervene in a more comprehensive way.
Thank you for pointing this out - The medical machine is famous for doing unnecessary things for money, and older Americans are seemingly a huge pocket with Medicare.
Isn't there risk inherent in Any surgical procedure, aside from the obvious boondoggle of taxpayer funds and taking up space, time & manpower in medical facilities?
If anything, this is worse now, as hospitals got used to being filled to the brim during Covid, many are closing for various reasons, and my home, South FL is overrun with retirees on whom so many doctors do this crazy stuff.
Surgeons depend on what for their living? Surgery. So they're referred to a surgeon for Any asymptomatic issue. What do we think the surgeon will say, "Oh, no, this doesn't have a big benefit..." (To scheduling dept) "Incoming", and "Next!"
John,
Like you my priors on revascularization for asymptomatic carotid stenosis have been extremely negative. I haven't referred such a patient for CEA or CAS for 15 years and I've written a lot about the risks of these procedures (https://open.substack.com/pub/theskepticalcardiologist/p/what-are-the-dangers-of-unnecessary?r=1f2oz2&utm_campaign=post&utm_medium=web&showWelcomeOnShare=false)
TCTMD has a balanced discussion on this but with a headline that reads
"Long-Awaited CREST-2 Results Bolster Stents for Asymptomatic Carotid Stenosis"
The 3.2% absolute difference in the rate of the primary outcome favoring intervention, resulting in a number needed to treat of 31 is impressive, however (even if fragile)
and raises the possibility that stenting might be useful.
The interventionalists will seize on this to promote carotid stenting. The TCTMD articles quotes one as saying
“In the neurovascular and neurointerventional community, we are excited and welcome these results as this is a big paradigm shift in evidence-based treatment of patients with asymptomatic carotid disease,” SVIN President Thanh Nguyen, MD (Boston Medical Center, MA), commented to TCTMD."
ACP
Now apply IMM to the real world and I think the bar to stenting lowers quite a bit. The signal for stenting was small but that was in patients selected to be highly motivated for IMM - hence agreeing to be in the study - who were no doubt hounded by coordinators to stay on track. Even so the adherence rates were not great - so what will they be in the real world?
If anything I think the study strongly points to stent - as IMM is not likely to be adhered to.
As in all things, judgement enters the picture. Smoking hypertensive patient with poor medical compliance? Stenting is potentially a better option. Retired engineer who brings charts of his BPs and pulse to visits, with a two page printed medical hx, who is hyper cholesterolemic and hypetensive? Medical therapy is likely appropriate.
Device/procedure vs medical management studies today are occasionally patient focused. Often, they are about the procedure (supported by a generous grant from ACME Medical Devices). They don’t LIE; they do, however cherry-pick, and at times make pronouncements about all patients in a study population, when only certain subgroups are truly appropriate. While the ads in the Journal of XYZ shout “ACME Device: Proven Statistically Superior to Medical Management”. Leading clinicians who are either too trusting, incurious, or predisposed to that option, to apply a broad brush in the clinic.
Judgement is challenging, and takes more time. Applying a broad brush is quick, and easy. Pharma and Device Inc count on clinicians to do the latter.
Let’s all do our best to disappoint them, shall we?
Yes, it's a Built-in supply of patients to be scared into stuff, or sold it on TV.
One of our residents watches the Hallmark channel (and they're by No means the only ones to do this) and nearly ALL the commercials are for a drug or a medical device or procedure. I'm not a fan of selling things to this captive audience. Can we just watch a feel-good movie and let the elderly woman rest without pointing out all the scary things she can be saved from by simply Finding a doctor willing to prescribe it? I don't doubt commissions are paid because I know a couple of ex drug reps who say they ARE paid (even if 'in-kind') to physicians, a huge conflict of interest.