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Screening BODY HANDBOOK
Screening Β· Β§90
Abdominal Aortic Aneurysm Screening
A bulge in your aorta β€” the body's main pipe β€” can sit there for years without a symptom, then split open and kill you in an afternoon. If you're a man over 65 who has ever smoked, a one-time ten-minute belly ultrasound finds it before that happens. The scan is painless, free under Medicare, and a negative result rules out the problem for the rest of your life. Decline it and you're betting on odds that ruptured aortic aneurysms kill roughly four out of five people they happen to.
Test Β· Once Evidence Strong Chapter Screening

The win is binary: most men get a negative scan and never think about it again; a small slice get a bulge caught early and an elective operation instead of an ambulance ride. Four large trials show roughly half as many aortic-aneurysm deaths in screened older men Cochrane 2007. The cost is a fasted morning and a quick ultrasound β€” no needles, no radiation, no follow-up if the aorta looks normal. The catch worth knowing: a small bulge found at screening means yearly rescans, which a meaningful minority of men find genuinely stressful.

The aorta is the body's largest artery β€” the pipe carrying blood out of the heart, down through the chest and belly, before it branches to the legs. With age, smoking history, and chronic low-grade inflammation of the vessel wall, a segment in the lower belly can balloon outward. An aneurysm means the diameter has grown past about 3 centimetres. Below that, the aorta is just an aorta. Above it, the wall has thinned and stretched, and at some unpredictable threshold β€” usually well over 5 centimetres β€” it splits open.

Until it does, you feel nothing. There's no chest pain, no shortness of breath, no warning. The bulge sits anterior to your spine, hidden behind belly fat and bowel gas; a doctor can sometimes feel it on careful palpation, but smaller ones get missed almost every time. That silence is the entire problem screening solves.

An ultrasound probe pressed against your belly bounces sound off the aortic wall and reads the diameter to within a millimetre or two. The scan picks up clinically relevant aneurysms more than 95% of the time and is wrong in the other direction less than 1% Guirguis-Blake 2019. No radiation, no contrast dye, no needles. Because aortas grow slowly β€” about two or three millimetres a year when they grow at all β€” a single negative scan at 65 reliably rules out a dangerous aneurysm for the rest of your life.

What the trials actually showed

Four large randomised trials β€” in the UK, Denmark, and Australia β€” pulled the same lever: invite a population of older men to a single ultrasound, see what happens over the next decade. They all landed in roughly the same place. Screened men were about half as likely to die from a ruptured aortic aneurysm Cochrane 2007. The MASS trial β€” the biggest, 67,800 British men aged 65 to 74 β€” followed participants for thirteen years and the benefit held the whole way Thompson 2012.

That's the cause-specific number. The harder question is whether screening makes you less likely to die at all, from anything, in the years that follow. Aortic aneurysms are one cause of death among many at that age. When you pool the trials and follow the data out far enough, the all-cause mortality signal is small but real β€” a hazard ratio of 0.98 across the longest follow-ups, which translates to a few extra survivors per thousand invited Ali 2016. That's the right way to frame it: screening doesn't make you immortal; it removes one specific way you might have died.

The mortality math is mechanical. An aortic aneurysm that ruptures kills roughly four out of five people it happens to β€” about half before the ambulance arrives, the rest in the operating room or the hours after Reimerink 2013. The same aneurysm operated on while it's still intact carries a mortality of about one to four percent Powell 2017. Screening turns a near-certain death into a near-certain recovery for the people whose aneurysm was going to rupture anyway. It does nothing for everyone else β€” which is most people scanned.

What happens if you skip it

You almost certainly don't have an aneurysm. Most older men don't β€” current prevalence in men 65 to 75 who have ever smoked is somewhere around two to four percent, lower in never-smokers USPSTF 2019. Skip the scan and the most likely outcome is nothing at all β€” you go on with your life, the aorta behaves itself, the universe never tells you the screening was unnecessary.

The other branch is what the trial numbers are about. A small percentage of men have an aneurysm growing quietly through their late sixties and seventies. The first sign is, often, the last sign β€” sudden tearing pain in the back or belly, collapse, the kind of phone call that comes from a hospital instead of from the person it's about. About half don't reach the hospital alive Reimerink 2013. The ones who do go into emergency vascular surgery, where roughly a third more die in theatre or in the days after.

That's the trade you're declining when you skip the scan: not a guaranteed bad outcome, just the one in fifty or one in thirty roll of the dice where you wouldn't have made it. The wife or daughter who finds out from a doctor instead of from you. The version of the next decade where you weren't around for it. Anchored to the screened-vs-unscreened comparison in MASS, that's roughly three men per thousand invited who got more years they wouldn't otherwise have had Thompson 2009. Most of the other 997 lost nothing by getting scanned.

How to actually get screened

In the US, ask your primary care doctor for an abdominal aortic aneurysm ultrasound, or bring it up at your Welcome to Medicare visit in the first year you turn 65 β€” Medicare covers a one-time scan for men who have ever smoked and for anyone with a family history of aneurysm. The billing code is G0389. In the UK, you'll get a letter automatically in the year you turn 65 inviting you in. Outside of programmes that find you, you have to ask.

That's the whole protocol. There's no preparation beyond the fast, no follow-up appointment if the scan is clean, and the surveillance pathway runs itself for people whose scan isn't clean.

Who this is actually for

The clean recommendation is men aged 65 to 75 who have ever smoked β€” a hundred cigarettes lifetime counts. That's the group the trials enrolled, and the group the US Preventive Services Task Force gives its strongest endorsement USPSTF 2019. If that's you, this is a one-time test with multiple large trials, decades of national-programme data, and Medicare coverage behind it. Get it done.

The picture greys out beyond that group.

Men 65–75 who never smoked: the official guidance is "consider it" rather than "do it" USPSTF 2019. Aneurysm prevalence in this group is roughly 1%, so the math gets thinner β€” most never-smokers won't have one. Reasonable to ask a doctor about it; reasonable to skip if your doctor reads it that way too.

Women 65–75 who have ever smoked or have a relative with an aortic aneurysm: US Preventive Services Task Force says the evidence isn't strong enough to recommend for or against β€” no trial in women has shown the benefit men get USPSTF 2019. The Society for Vascular Surgery is more permissive and does recommend screening this group SVS 2018. Worth bringing up with a doctor; not something to assume is automatic.

Women 65–75 who never smoked and have no family history: don't get screened. Prevalence is too low for the test to find more than noise.

Anyone with a parent, sibling, or child who had an aortic aneurysm: first-degree relatives carry roughly a ten to fifteen percent chance of having one themselves, and they get them younger SVS 2018. This is the one situation where screening earlier than 65 is reasonable, and it applies to women as much as men. Ask a vascular specialist what age makes sense given your relative's diagnosis.

What most people get wrong

"You need it every few years." No. One clean scan at 65 in a man with a normal aorta is essentially a diagnosis for life. Aortas don't suddenly start ballooning at 78 if they were fine at 65. The UK national programme and US guidelines both treat this as a single intervention, not a recurring screening like mammography or colonoscopy.

"If it's found, I'll need surgery." Most found aneurysms are small and go into monitoring, not the operating room. Repair only happens when the diameter crosses about 5.5 cm β€” most people in surveillance never reach that. The 1990s trials that established the threshold showed no survival advantage to operating on aneurysms smaller than that UKSAT 1998, Lederle 2002.

"My doctor would have caught it at a checkup." A doctor pressing on your belly can feel a large aneurysm in a thin person, sometimes. Small and medium ones get missed almost every time. Physical exam isn't a substitute for ultrasound.

"I feel fine, so I'm fine." The entire point of the test is that you feel fine until you don't. Symptoms β€” sudden severe back or belly pain β€” are the rupture, not a warning before it.

Where this goes wrong

The dominant failure is not getting screened at all. Among US men eligible for the Medicare benefit, well under half actually use it β€” not from opposition, just from logistical friction and from doctors not bringing it up. The intervention works only on the people who get the scan.

A second failure happens after a small aneurysm is found and the patient drifts out of surveillance. The annual rescans are how the system catches the diameter crossing the surgical threshold; miss enough of them and an aneurysm that could have been caught at 5.4 cm presents as a rupture instead. If you're put into surveillance, treat the rescans like a recurring appointment that doesn't move. Two things help keep a small bulge from growing between scans: keeping your blood pressure controlled, since it's what keeps pushing on the weakened wall, and flagging the aneurysm before you're prescribed a fluoroquinolone antibiotic β€” a class linked to aortic tears that usually has alternatives.

The third failure is psychological. A meaningful minority of men diagnosed with a small aneurysm β€” somewhere around one in ten in surveillance cohorts β€” report serious anxiety, intrusive thoughts about sudden death, restrictions on physical activity or travel plans Johansson 2018. This is real. Most men handle the diagnosis fine; some don't. If you're in surveillance and the worry is reorganising your life, tell your doctor β€” it's a known harm of the screening pathway, not a personal failure, and it can be addressed.

What you actually get out of it

For about 96 or 97 men out of every 100 scanned, the payoff is a piece of paper that says the aorta looks normal and a doctor saying you're done forever. That's it. Nothing about your day changes. You feel exactly the same the next morning. That's the point β€” most of the value of a screening test is the negative results.

For the few percent whose scan finds something, the payoff plays out over the next several years. A small aneurysm enters surveillance; most of those people watch it move a millimetre or two a year and never need surgery. A smaller subset cross the threshold and get an elective repair β€” a planned operation with a survival rate around 96 to 99% Powell 2017, instead of the 15 to 35% survival of an emergency repair after rupture.

At the population level, the trial data line up cleanly: roughly three men per thousand invited to screening reach a decade later that they wouldn't otherwise have reached Thompson 2009. Not visible in any one person's life. Visible across the whole cohort, and visible at the level of who's still at the dinner table fifteen years later.

Cost and logistics

In the US, Medicare Part B covers a one-time AAA screening ultrasound with no deductible or copay for men 65 to 75 who have ever smoked and for anyone with a family history. The benefit is easiest to claim during the Welcome to Medicare visit in your first twelve months on the programme. Outside that window, the same scan as a self-pay diagnostic ultrasound runs roughly $100 to $300 at most outpatient imaging centres.

In the UK, the NHS Abdominal Aortic Aneurysm Screening Programme invites every man in the year he turns 65 automatically β€” no doctor's referral required. Uptake runs around 80% Jacomelli 2016. Similar national programmes exist in Sweden and parts of the rest of Europe.

Practical day-of logistics: skip food for four to six hours so the bowel isn't full of gas blocking the view of the aorta. Bring nothing. The scan is done lying on your back with the technician moving a probe across your belly. Five to ten minutes. Most centres can give you the diameter and a verbal read at the same visit; the formal report goes to your primary care doctor within a few days.

Adjacent topics worth looking into: thoracic aortic aneurysms β€” different anatomy, different screening rules, mostly relevant to people with bicuspid aortic valves or connective-tissue conditions like Marfan. Peripheral artery disease, often picked up at the same vascular workup and a common companion to aortic disease in older smokers. Smoking cessation, which remains the single largest modifiable factor for both growth and rupture of an aneurysm that's already there. And cardiovascular risk reduction more broadly β€” statins, blood pressure, exercise β€” which is how most older men actually move their long-term mortality numbers, screening or no screening.

Related in the handbook
Worsens / aggravates
  • β€” Smoking is the single biggest driver of an aortic aneurysm β€” if you've ever smoked, that's exactly why this scan exists.
  • β€” If you have an aortic aneurysm, flag it before a fluoroquinolone; the class is linked to aortic tears and usually has alternatives.
  • β€” High blood pressure pushes on a weakening aorta β€” controlling it helps keep a small bulge from growing.
Related
  • β€” Same logic as cancer screening: a quick scan at the right age catches a silent killer while it's still fixable.
  • β€” This one-time scan slots into the same age-triggered rhythm as your other preventive checks.
  • β€” An aneurysm is atherosclerosis in the aorta's own wall. The particle count that drives plaque drives this too β€” worth knowing yours.
  • β€” Same plumbing, different spot. If your aorta bulges from years of plaque, a calcium scan shows what the heart arteries are doing too.
  • β€” Both this scan and the yearly lung CT are aimed at ex-smokers. If you qualify for one, check whether you're due the other.
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