High blood pressure, also known as hypertension, is an enormous medical problem in the United States and around the world, likely impacting directly or through family members virtually everyone we interact with on a daily basis. Its reach is staggering; affecting about 70 million
adults in the United States (that’s one in every three adults), and about 1 billion
people worldwide. It is a leading cause of heart attacks, strokes, heart failure, and death, and associated healthcare costs run close to $50 billion
each year in the United States alone.
Despite the multitude of available drugs proven to lower blood pressure successfully when used properly, the elevated blood pressure of roughly half of affected people in the US is still not considered well controlled. There are two major reasons why treatment for hypertension does not lower some patients’ blood pressures. First, some patients need to be prescribed a complex regimen involving three or more different antihypertensive medications. These patients would likely benefit as well from specialist care rather than relying on family practitioners who may be less focused on the hypertension versus other medical issues. Second, some patients may have trouble consistently taking the medications they’re prescribed. While precise figures are difficult to get, reliable estimates suggest that about half of patients fail to comply with their prescribed treatment regimen.
For some of the most difficult patients, however, their blood pressure remains too high even when getting help from hypertension specialists and taking their tablets exactly as prescribed. These patients are said to have resistant hypertension. Over the last 10 years, therefore, there has been a lot of interest in an interventional procedure to treat resistant hypertension and potentially many other diseases caused by the same physiologic issues that lead to resistant hypertension. The procedure is called renal sympathetic denervation (RDN), and there are various ways of performing the procedure. Some systems employ a radio-frequency energy to ablate renal nerves that contribute to raising blood pressure, while others use alternate methods of ablation such as ultrasound energy. The underlying rationale for this medical device therapy is that renal nerves play a key role in hypertension via their effects in the kidney that enhance renal sodium retention and renin secretion while also exerting hypertensive effects in the central nervous system that lead to increased systemic sympathetic activity.
At this time, RDN has not been approved for use in clinical practice by the United Stated Food and Drug Administration, since more evidence of the procedure’s long-term safety is needed, and it is not yet clear which type of patients are likely to get the most therapeutic benefit (i.e., lowered blood pressure). The American Society of Hypertension
recently published a report
that outlines the kind of clinical trials needed to collect the data regulators will want to review before making a marketing approval decision. It will be of great interest to many healthcare professionals to follow progress in this field over the next few years.