With a new way of scanning, doctors can easily detect and eliminate a common cause of high blood pressure. Patients often no longer need medication.
A radioactive tracer stains small groups of gland cells in the adrenal gland that make a blood pressure-raising hormone. These small growths were not always discovered in the past and could only be found in an adrenal vein with a difficult catheter examination. British researchers described their new method in the scientific journal on Monday Nature Medicine.
High blood pressure (hypertension) is very common, about one in four Dutch people have it – even one in two people over the age of 65. It does not always cause complaints, but it increases the risk of a stroke, a heart attack or kidney failure. In the vast majority of cases, the cause is not known – often it runs in the family and there are hereditary factors.
Licorice or licorice tea
In about 1 in 10 people, a cause can be identified. This can be, for example, an excessive consumption of licorice or licorice tea, but it is usually due to an excessive production of the hormone aldosterone. This hormone regulates the salt concentration in the body and plays an important role in blood pressure regulation. The overproduction is often due to a benign tumor in the adrenal gland. If it is in one adrenal gland, then surgery to remove that adrenal gland often solves the problem completely; if both adrenal glands are involved, a patient is given anti-aldosterone medications.
The small growths are easily missed on a regular CT scan. It is estimated that less than 1 percent of people with hyperaldosteronism (an excess of aldosterone) are recognized and fully investigated. Doctors don’t always think about it because it has long been thought that this condition is rare. And the catheter examination in the adrenal vein is very complicated and can only be done in specialized centers with limited capacity.
Small growths in the adrenal glands were always very difficult to find
With the new method, patients receive a dose of a short-acting radioactive tracer just before the scan, [11C]metomidate, which sticks only to certain enzymes in the aldosterone-producing tumor. With a combination of two commonly used scanning techniques, PET and CT, the benign tumor can then be found.
The UK study involved 146 patients whose high blood pressure had been shown to be caused by too much aldosterone – 128 had sufficient data. They underwent both the usual examination and the new scanning method. With the new method, it turned out in 78 of them, almost two-thirds, that a benign growth on an adrenal gland was the culprit. The doctors could easily remove them surgically. In 23 of those patients, the blood pressure was normal at the six-month follow-up without the need for any further medication. The rest were still on medication for high blood pressure.
The scan was at least as accurate as the complicated catheter test, but faster and painless. The new method also makes it easier to predict which patients will completely get rid of their high blood pressure after surgery.
“This invention has the potential to make it easier to determine whether surgery is possible in many more centers than now – the holy grail for this disease,” says Jaap Deinum, internist-vascular physician at Radboud UMC in Nijmegen. “The anti-aldosterone drugs can have nasty side effects, such as impotence, so if you can operate, you should always do that. This form of hypertension is insidious and produces many more complications such as stroke, heart failure or arrhythmias.”