The examination includes identifying the underlying cause in patients suffering from excessive aldosterone production.
It is estimated that about a quarter of people with high blood pressure have excess aldosterone production by the adrenal glands. Aldosterone is a hormone that regulates salt levels in the body. This condition is often overlooked because diagnosis is complex and requires multiple tests, while treatment in some cases may require surgery, the results of which are not always guaranteed.
Excessive aldosterone production leads to salt retention and high blood pressure, a condition known as primary aldosteronism, which increases the risk of heart disease, stroke, and kidney disease. However, some people do not meet the official criteria for this condition, yet their high aldosterone levels still cause high blood pressure.
Currently, a blood test is performed for diagnosis, followed by a second test for confirmation. This is then followed by a complex procedure involving the insertion of two catheters into the groin veins to measure aldosterone levels on each side of the body. This helps doctors determine whether the problem is in one adrenal gland or both, but the test is not always accurate and is rarely performed due to its complexity.
To overcome these difficulties, the researchers used PET-CT scanning, which produces accurate three-dimensional images and shows the accumulation of a radioactive tracer compound injected into the patient's vein.
The team developed a tracer compound that binds to the enzyme responsible for aldosterone production, aldosterone synthase. Adrenal glands that overproduce the hormone selectively absorbed this compound, causing them to glow in the scan.
In the first use of this technique on 17 patients at University College London Hospital, researchers were able to accurately pinpoint the source of excessive aldosterone production, without any side effects.
The researchers say the test, which takes just 10 minutes, will make it easier to determine the best treatment, whether it's removing the overproducing adrenal gland or using new drugs that inhibit aldosterone production, targeting the root cause of patients' high blood pressure.
Professor Brian Williams, head of the Department of Medicine at University College London and clinical lead of the study, noted: "We have been waiting for a test like this for many decades. This innovation will be a game-changer in the diagnosis of hyperaldosteronism as an important hidden cause of high blood pressure, and will enable us to deliver more precisely targeted treatment."
Williams explained: "This is the first time we have been able to image the disease. The intensity of the signal reflects the level of overproduction of aldosterone, and we may be able to target these areas more precisely in the future."
Now, the team is embarking on a phase two clinical trial to gather enough data to approve the test for routine use in the UK's National Health Service.
The study was published in a research letter in the New England Journal of Medicine.
