Spend some time studying the subject of renal denervation and you’re likely to pick up hints that it could have therapeutic effects beyond the treatment of hypertension. Now St. Jude Medical, Inc. has announced plans for a new landmark study to explore these potential health benefits.
Uncontrolled hypertension occurs when blood pressure in the arteries remains elevated, requiring the heart to work harder than normal to circulate blood throughout the body.
The World Health Organisation estimates that 7.5 million deaths each year, or 13 percent of all deaths can be attributed to raised blood pressure. Notably this includes 51 percent of deaths due to stroke and 45 percent of deaths due to coronary heart disease.
Along comes renal denervation therapy, by now well-known to the readers of our pages. In essence it is a minimally invasive procedure that uses radiofrequency (RF) energy to disrupt the renal nerves, which lead in and out of the kidneys. The RF energy creates lesions along the renal sympathetic nerves – a network of nerves that help control blood pressure. This intentional disruption of the nerve supply causes systolic and diastolic blood pressure to decrease.
St.Jude’s new so-called “EnligHTNment” trial is the first large-scale study to examine the long-term effects of renal denervation in patients who have uncontrolled hypertension. What they are looking for is evidence that the procedure also reduces the risk of major cardiovascular events such as heart attack, stroke and death. What they are likely to find is that renal denervation will be associated with a reduction in other heart-related diseases.
And St.Jude probably know this, because their homework will have told them that the primary impact of renal denervation, according to the scientists who originated the technique, is on the heart: The therapy works by influencing the sympathetic nervous feedback mechanism. This in turn sees a decreased heart rate and heart muscle tone, with a consequent decrease in blood pressure. You could equally assume that by de-stressing the heart in this way, one will see a decrease in cardiac conditions some of which are themselves provoked by a stressed heart. Nonetheless it’s likely to prove an interesting insight into how this complex neurovascular feedback loop plays out.
“To date, the renal denervation studies that have been conducted only looked at reducing blood pressure in patients with uncontrolled or resistant hypertension,” said Professor Michael Böhm, director and chief of internal medicine and cardiology at the University of Saarland in Homburg/Saar, Germany, a principal investigator for the trial. “What we need to know is if this minimally invasive approach for treating hypertension also correlates to a reduction in major cardiac events such as heart attack, stroke and death, which are the primary risks for patients whose blood pressure is not well controlled.”
“Initial study results have demonstrated that the EnligHTN Renal Denervation System is safe and effective in rapidly lowering blood pressure. If these results extend into the prevention of major cardiac events, there is the potential to dramatically change how we treat these patients,” said Professor Thomas Lüscher, chairman, cardiology and cardiovascular center at the University Hospital in Zurich, Switzerland, a principal investigator for the trial.
“We are committed to making the right investments to lead the emerging field of interventional treatment for hypertension,” said Frank J. Callaghan, president of the St. Jude Medical Cardiovascular and Ablation Technologies Division. “Like other landmark trials we have sponsored, this first-of-its kind study provides the opportunity to evaluate patient outcomes that matter the most – heart attack, stroke and death.”
In 2012, the EnligHTN Renal Denervation System earned European CE Mark approval and was launched in several markets. It is not yet approved for use in the U.S.
Source: St.Jude Medical, Inc., Business Wire