First, this is an example of data reuse from RCTs (in this case BARI-2D). Data are made available by @nih_nhlbi through BioLINCC repository. Some paperwork is required to ensure patient privacy, etc but process is usually straightforward & quick:
Another thing is this study reminded me that the outcomes of the PCI stratum in BARI-2D were actually numerically worse for the revasc arm vs. medical therapy:
Using the endpoint of death or MI at 1 year, this was actually significantly worse for PCI than OMT alone.
One question from @DavidLBrownMD is how much of this was periprocedural? From KM plots looks like at least the MIs are likely to be, which some people dismiss as not all that important. However, in this case it is paralleled by a similar, but non-significant, excess of death.😱
The clever thing done by this team is something that is akin to a *randomization test*. What they did was randomly pretend that some of the PCI patients were deferred by substituting patients from the OMT arm in their place.
They did this lots of times with varying % of patients substituted. This is one form of Monte Carlo simulation, a generic term for a simulation where you repeatedly making a random change and seeing how it affects the outcome.
Obvs if everyone in the PCI arm was deferred, the outcomes would be essentially the same as in the OMT arm.
Conversely, if everyone in the PCI arm got treated the way they did in the trial, nothing much would change at all.
In between, you get a smooth reduction in adverse outcomes as you do less PCI.
So, in some ways this isn't surprising. The moment you realize that PCI had worse outcomes, it kind of follows that less of it leads to better outcomes.
That said, this is a clever way to demonstrate that numerically and graphically.
Some caveats - the revascularization outcome alone was neutral so this is a subgroup of an overall negative trial. That is partially mitigated because the randomization was stratified around this subgroup.
Also, over time the difference observed in the PCI stratum was non-significant it seems.
That said, it does seem there is a consistent message among many SIHD trials of early harm from PCI vs. OMT that may or may not reverse much later on. Similar results are seen in ISCHEMIA.
Overall, congratulations to @DavidLBrownMD and Conor Williams for a very clever analysis!
So, I misrepresented. This ended up being more than a MINI-thread.
But was this helpful?
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I am hearing from primary care colleagues that parents are concerned their kids are playing competitive sports without EKG/echos.
More valuable than that would be to mandate no games/practice without AED + CPR trained coach, trainer, and/or official present.
Here is why 👇
1/
Screening for underlying issues in fit teens and young adults is low value. The findings are almost always normal and even when they appear abnormal they are usually false positives.
2/
These kids will end up having lots of expensive & potentially invasive testing which will either lead nowhere or lead to an incorrect recommendation not to exercise at a high level. This is tragic and wasteful.
Imagine incorrectly being told you can't play a sport you love!
3/
To be honest, this is even more complex than the factors in my initial thread. Been rounding so couldn't give it enough detail, but here are few more...
A baseball will deposit that energy in a smaller surface area than a human head generally will. The concentration of that energy is required because if parts of it are not over the heart they won't cause a cardiac problem
2/
The deformation issue is also more complex.
Not only does deformation reduce the energy transferred, it spreads out the time over which the energy is transferred making it more likely part of the energy is deposited outside the vulnerable period.
3/
Generally trauma to the chest from person-person deposits only a small amount of energy into the heart compared to small hard objects like a baseball or motor vehicle collisions.
The amount of energy is proportional to the square of the velocity of the impact.
1/
There is a huge difference in the square of 90+ MPH fastball (9025 mph-squared) version a 10 MPH person (100 mph-squared) - nearly 100x!
Mass also matters, but the effective mass is not necessarily entire mass of person impacting but unsupported mass, depending on geometry.
2/
Also, some energy can be lost to deformation. This is how padding works - it deforms, dissipating energy.
Humans are also somewhat deformable due to motion of joints, soft tissue, etc.
3/
1) The self-limited troponemia referred to is not a diagnosis. The diagnosis is myocarditis, post-COVID vaccine
2) The relative awfulness of these diseases is not the only issue. Their relative frequency is not the only issue.
3) Myocarditis is a spectrum. Can range from rapidly progressive to death to mild chest pain with no further consequence. Like most diseases, the mild forms are much more common than the severe.
#2 Is that few MRI experts were asked before/during hype. Sports cardiologists & celebrity docs dominated the scene with weak understanding of what these tests were showing & what they showed in normal people.
Selective credentialism sucks.
#3 Early closing of the Overton window is not science. But in this fact checking culture we are quick to determine what is truth and terminate further discussion.
In this case the estimated rate of CMR findings due to COVID was probably off by 100x or more at first.