Resistant hypertension carries a significant treatment burden because blood pressure cannot be lowered to the target level despite taking multiple medications. The psychological burden associated with taking more medications and concerns about drug side effects may increase. Poor blood pressure control also exposes patients to the risk of major complications, including stroke, myocardial infarction and peripheral vascular disease. This is why new treatment options are needed for patients with resistant hypertension. Choi Seung-hyuk, a professor of cardiology at Samsung Seoul Hospital, said, “For patients whose blood pressure is difficult to lower sufficiently with medication alone, treatment methods that can supplement drug therapy are needed.”
◇Lowering sympathetic nerve activity around the renal arteries to control blood pressure
Renal denervation, RDN, is considered the only alternative available for patients with resistant hypertension. The procedure lowers the activity of the sympathetic nerves involved in blood pressure regulation around the renal arteries. A catheter is inserted along the renal artery, after which energy is delivered to the vessel wall to reduce the activity of the surrounding nerves. The procedure is performed by inserting a thin catheter through a blood vessel near the groin to the renal artery, and it can generally be completed within an hour, including preparation. The effects of renal denervation have been confirmed in multiple clinical trials.
In the SPYRAL OFF MED study involving patients who were not taking antihypertensive medications, office systolic blood pressure decreased by an average of 9.2 mmHg and 24-hour ambulatory systolic blood pressure decreased by an average of 4.7 mmHg three months after the procedure. The reduction was observed in nighttime blood pressure as well as daytime blood pressure. In the SPYRAL ON MED study involving patients taking up to three antihypertensive medications, office systolic blood pressure decreased by an average of 9.9 mmHg six months after the procedure. This was similar to the reduction in blood pressure expected from adding one type of antihypertensive medication.
Long-term effects have also been confirmed. According to the Global SYMPLICITY Registry DEFINE study, the reduction in blood pressure continued for up to three years after the procedure. An integrated analysis of 2,137 participants in four SPYRAL clinical trials also showed that the clinical benefits continued through 36 months after the procedure. Professor Choi Seung-hyuk said, “Long-term follow-up data through five and 10 years are now available, and the effects have been confirmed to persist over those periods,” adding, “Some studies have also presented results from even longer periods of observation.”
