Known Unknowns

Guest article, written by a cardiac critical care specialist.

I remember listening in silence in 2002 to Donald Rumsfeld setting out the case for invading Iraq. The US Secretary of Defense was preoccupied with weapons of mass destruction, and with explaining the various types of "knowns" and "unknowns" that might exist in the search for them.

At the time, those soundbites hardly seemed like a framework that could help anyone understand themselves better. Years later, I came to appreciate that the underlying idea — mapping what we know, what we know we do not know, and what we have not even thought to ask — is genuinely useful in medicine, particularly as we try to add precision to risk prediction.

When symptoms arrive too late

In heart disease, symptoms as a "known" outcome usually arrive too late for the most valuable interventions. There is a further unfairness: symptoms do not serve everyone equally well. Chest pain as a warning sign of heart attack is a more reliable indicator in men than in women, and presentations differ across ethnic groups. Even at this late stage, one of our clearest "knowns" can let us down.

Moving risk earlier

The question is how to improve precision and predictability as early as possible. One approach that has gathered real momentum is identifying inherited risk through genetics — until relatively recently, very much an "unknown".

Advances in whole genome sequencing have transformed diagnosis for some of the sickest children in the country, many of whom had lived for years without any explanation for their condition. For those families, sequencing has changed lives.

Why this matters for healthy people

As a cardiac critical care specialist, the question I am asked most often by acutely unwell patients is "why me?" After a sudden heart attack or stroke, dwelling on a previously healthy life is entirely understandable, and accepting a life-changing diagnosis is extremely difficult.

Information about the likelihood of cardiovascular disease has always existed, but usually as population-level statistics. Those figures serve an individual poorly when they arrive in hospital critically unwell. When you are sick and frightened, there is little consolation in knowing that others avoided this.

To any given individual, heart disease is very much an all-or-nothing event. What is far more useful is identifying risk early enough to modify it, with expert guidance. While healthy, we have the opportunity to identify, stratify and act on our individual risk. There is no crystal ball — we cannot know how things will unfold decades later — but early changes to lifestyle and diet can make a substantial difference to both peace of mind now and quality of life later.

A collective effort

As the field grows, prediction improves for everyone. There is a reasonable case that we each have some responsibility to contribute anonymised data to strengthen the models we ourselves benefit from. We stand on the shoulders of those who came before us in this field.

Information is power. Given the choice, I would rather understand my own risk than be left wondering about the unknowns.

Assessing your cardiovascular risk

Rightangled's home blood tests can measure cholesterol, lipids and HbA1c, and our DNA tests assess inherited cardiovascular risk markers. Results are reviewed by our clinical team, which includes GPhC-registered independent prescribers, with medical oversight from our doctor, Dr Abdullah.

If you have a strong family history of heart disease or early sudden death, speak to your GP about referral to a specialist inherited cardiac conditions clinic.

Related reading: silent heart attacks.

Guest articles reflect the views of their authors. This article is for general information and does not replace personalised medical advice.