I often hear stories of a guy who has a heart attack and come to find out that 95% of a major blood vessel to the heart was clogged.
How is this not picked up earlier during normal exams? Why isn’t it?
Can’t they do radiation shots to see where the blood flows or whatever?
In: Biology
Arteries isn’t something that takes 2mins to check in general practice visit, you need an invasive observation to confirm to put it simple.
Generally, doctors try to avoid subjecting patients to unnecessary radiation because the costs exceed the benefits. Also, I believe that the dye you have in mind can be hard on the kidneys, and I also believe that a small number of people are allergic to it, which can be a major health issue itself.
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There are different ways to get to the same result. The trouble with screenings is that they create some number of false positives and aren’t as reliable as lay folk imagine. This is an ongoing controversy in the cancer world. Some clinicians for decades argued for detailed cancer screenings for all. Test results ended up being misinterpreted, and there were surgical interventions that didn’t have to happen and likely wouldn’t have happened without the screenings.
The arteries on the surface of your heart are… Small. You can’t see them from the outside. There’s lots of risk factors for having coronary artery disease and if you have any of them, like a family history, high cholesterol, or it shows up on other tests (like a stress test) then the doctors will pay much closer attention. But to routinely screen people with no risk factors who haven’t displayed any other signs, just isn’t feasible. Cardiac cath procedures are incredibly invasive and not 100% safe.
Often if someone’s artery is THAT clogged you would likely have symptoms. Chest pain when exercising or emotional stress, or some equivalent (worsening shortness of breath on exertion, nausea on exertion, upper stomach pain on exertion). If someone lives a very sedentary lifestyle where they just lay on the couch all day they might not notice.
If that happens then you would do further testing, generally some sort of stress test or imaging study. But the rule of thumb is if an artery in the heart is more than 70% blocked you can start to have SOME sort of symptom. You can’t just screen the entire population due to cost reasons and just from a work force perspective, there’s not nearly enough cardiologists to do that many procedures
They DO check. It boils down to: it depends.
You have to divide people into 2 groups. People with chest pain, and people who don’t have chest pain.
If you are having chest pain when you’re walking, going up stairs, etc, then you might be at risk of a heart attack. You might get imaging tests like a coronary CTA or nuclear stress test or exercise stress test.
If you are not having chest pain, which is basically the entire population, then there are step-wise ways to risk stratify people, because it’s not feasible or useful to run every single test on every single person. It costs a lot of $$$ and it’s not utilitarian to do 1 million tests to find only 1 patient.
Your risk factors for having a heart attack are many: age, high cholesterol, high blood pressure, diabetes, family history of heart attacks (“my dad had a heart attack when he was 48”). If you check off multiple of those boxes you might get a coronary calcium score CT which is an imaging test. If that’s normal then great. If it’s abnormal you might get pushed up into the same category as people with chest pain, and get more imaging tests like a coronary CTA or nuclear stress test or exercise stress test.
So when you go to your doctor for an annual physical and they ask you:
Are you having any chest pain lately?
Are you exercising?
Has anyone in your family had heart disease?
And they check your blood pressure.
And they have you get blood draws for hemoglobin A1C, fasting glucose, cholesterol.
These ARE the stepwise ways in which they’re picking out who is at risk of heart attacks and who to do MORE tests on.
When a heart attack happens, it is actually arteries that are mildly blocked (20-30%) with plaque that suddenly rupture and form a platelet clot. So these patients do not have symptoms, living their life OK with a 20-30% blockage and within an hour suddenly form a blockage of 95-100%. This is what is seen during heart attacks and immediately treated with cardiac catheterization and stenting. Doing invasive testing and treating those asymptomatic 20-30% lesions will cause more harm that good.
If you have a stable 70-90% blockage, it is something that has grown slowly and causes angina or chest pain during exertion. These are usually not the blockages that cause heart attacks and sudden death.
Lots of generalizations here but this is ELI5.
Invasive testing by shooting dye into the arteries and using X-rays to see it is expensive and not without risk. You can completely injure the blood vessel, cause a stroke, have access site complications, etc. It’s also expensive.
So instead doctors will get non invasive tests like CTs or ultrasounds to see if there is narrowing of the blood vessel. If you are generally unhealthy or a smoker, there is a lower threshold for screening.
We’re actually getting there. There’s a new elective CT scan you can have done that appears to be a reliable predictor for cardiac events. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8723785/
A few of my coworkers have had it, wound up being like $300 out of pocket without going through insurance at all.
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