Published today in Nature Medicine, the research solves a 60-year problem of how to detect hormone-producing nodules without a difficult catheter study that is available in only a handful of hospitals, and often fails. The research also found that, when combined with a urine test, the scan detects a group of patients who go off all their blood pressure medications after treatment.
128 people took part in a study of a new scan after doctors discovered their high blood pressure (hypertension) was caused by a steroid hormone, aldosterone. The scans found that in two-thirds of patients with increased aldosterone secretion, it was coming from a benign lump in just one adrenal gland, which could then be safely removed. The scan uses a very short-acting dose of metomidate, a radioactive dye that only sticks to aldosterone-producing nodules.
The scan was as accurate as the older catheter test, but was fast, painless and technically successful in every patient. Until now, the catheter test was unable to predict which patients would be completely cured of high blood pressure by surgically removing the gland. In contrast, the combination of ‘hot nodules’ on scan and urine steroid testing was detected in 18 of 24 patients who achieved normal blood pressure from all their medications.
The research, carried out on patients at Barts Hospital, Cambridge University Hospital, Guy’s and St Thomas’, and the universities of Glasgow and Birmingham, was funded by a National Institute for Health and Care Research (NIHR) and Medical Research Council (MRC) partnership. Bart’s Charity, and the British Heart Foundation.
Professor Morris Brown, co-senior author of the study and Professor of Endocrine Hypertension at Queen Mary University of London, said: “These aldosterone-producing nodules are very small and easily overlooked on routine CT scans. After our injection, they are revealed as a clear cause of high blood pressure, which can often then be corrected. Until now, 99% have never been diagnosed due to the difficulty and unavailability of testing. Hopefully that’s about to change.”
Professor William Drake, co-senior author of the study and Professor of Clinical Endocrinology at Queen Mary University of London, said: “This study was the result of years of hard work and collaboration between centers across the UK. Grounded’ energy and drive from talented researchers who, apart from doing this innovative work, selflessly gave their time and energy during the national pandemic emergency. The future of research in this area is in very safe hands.”
In most people with high blood pressure (hypertension), the cause is unknown, and the condition requires life-long treatment with medicines. Previous research by the group at Queen Mary University showed that in 5-10% of people with high blood pressure, the cause is a gene mutation in the adrenal glands.
Which results in the production of excessive amounts of the steroid hormone, aldosterone. Aldosterone causes salt to be retained in the body. which increases blood pressure. Patients with excessive aldosterone levels in the blood are resistant to treatment with commonly used drugs for high blood pressure, and are at increased risk of heart attack and stroke.