A small sham-controlled trial of Medtronic‘s (NYSE:MDT) Symplicity renal denervation device in treating mild but resistant hypertension failed to show any benefit for the therapy, echoing the results of the Symplicity-3 trial early this year.
The 71-patient Symplicity-Flex trial compared RDN with the sham procedure, using an endpoint of ambulatory blood pressure readings in patients with mild hypertension. After 6 months, the mean reduction from baseline was 7mmHg in the RDN arm and 3.5mmHg in the sham arm, not a statistically significant difference.
But excluding 2 patients with incomplete ablations, 1 who did not undergo the sham procedure and a 4th who did not meet the trials criteria because of renal artery stenosis, the study showed an 8.3mmHg reduction in the Symplicity-treated cohort and a 3.5mmHg reduction in the sham group, which was statistically significant.
Reporting the results at the annual Transcatheter Cardiovascular Therapies conference this week in Washington, Dr. Steffen Desch of the University of Leipzig Heart Center in Germany noted that the patient population in his Symplicity-Flex trial, which was not sponsored by Medtronic, was very different from the patients in the Symplicity-3 study, heartwire reported. The Symplicity-Flex study cohort showed a baseline systolic pressure of about 144mmHg, while the Symplicity-3 cohort’s baseline systolic was roughly 163mmHg, according to the website.
"This is a whole different patient population as compared with Symplicity HTN-3," said Desch, who noted that his clinic stopped performing RDN in January, just before Medtronic revealed the failed Symplicity-3 results.
Although he told MedPage Today that RDN for hypertension "may have an application in science, but not in the clinic except for the very rare patient," Desch said newer RDN devices with more electrodes might prove more effective than earlier devices, according to heartwire. Symplicity-Flex used 4 to 6 circumferential ablation runs of 2 minutes for each renal artery from distal to proximal, Desch said.
"If I were doing the trial again, I would recommend 10 to 12 ablations," he told the website.
"Given the fact that the magnitude of benefit in the per protocol analysis was small, it is certainly not conclusive evidence of a positive signal [for RDN in hypertension]," Dr. Deepak Bhatt of the Brigham and Women’s Hospital in Boston, who was a principal investigator in Symplicity-3, told MedPage Today.
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