Radiation therapy may be a promising alternative treatment for patients whose hypertension doesn't respond to medication, according to preliminary research being presented this week at the American Association of Physicists in Medicine (AAPM) annual meeting.
A team led by Peter Maxim, PhD, an assistant professor in the department of radiation oncology at Stanford University, found that radiation therapy could be used to disrupt the signals in the nerves that are wrapped around the main renal arteries. Blood pressure is controlled by a combination of nerve signals and hormonal interactions between the brain, heart, blood vessels, and kidneys.
Six hypertensive pigs were treated with 40 Gy of radiation in a single treatment to the nerves surrounding the renal arteries. All animals survived to the three-month follow-up point with no adverse events, and pathologic examination revealed moderate damage to the nerves and minimal damage to nearby critical organs. Blood pressure dropped in the animals by an average of 30%, a beneficial improvement but not enough to bring it to normal, according to the study team.
The group plans to conduct a future study with a two-year follow-up to determine dynamic changes in blood pressure. Future research will also consider how much radiation should be used and precisely what areas should be irradiated.
In another AAPM study that highlights the potential of radiation therapy for treating heart disease, a group led by Paul Keall, PhD, a professor of medicine at the University of Sydney, reported that MRI-guided radiation therapy could be an alternative treatment for atrial fibrillation.
The Australian researchers tested a special cardiac MRI exam on four patients, demonstrating that it's possible to image the beating heart accurately enough to guide radiation therapy to treat atrial fibrillation. The team said it is now working to further develop the cardiac MRI exam and test it in patients.
If those studies are successful, MRI-guided radiation therapy could offer a noninvasive alternative to patients with atrial fibrillation, according to the researchers.
