Conference Coverage
PARIS – Renal denervation may help lower blood pressure in patients with moderate hypertension that is resistant to drug treatment, a study has shown.
In a pilot, uncontrolled study with 54 patients at one German center, renal denervation was safe and reasonably effective for patients with treatment-resistant hypertension and an average baseline blood pressure of 151/82 mm Hg.
The patients in the study had persistent office blood pressure measures of at least 140/90 mm Hg but less than 160/100 mm Hg, despite stable treatment with at least three antihypertensive drugs, including one diuretic. To enter the study, patients also needed 24-hour blood pressure monitoring showing consistent blood pressure levels of at least 130/80 mm Hg.
Mitchel L. Zoler/IMNG Medical Media
Dr. Roland E. Schmieder
A total of 51% of the patients reached their target blood pressure of less than 140/90 mm Hg at 6 months after renal denervation treatment, Dr. Roland E. Schmieder said at the annual meeting of the European Association of Percutaneous Cardiovascular Intervention.
The percentage of patients reaching their goal pressure in the new study surpassed the outcome reported in the Symplicity HTN-2 trial, which showed that 39% of patients with severe treatment-resistant hypertension reached their goal pressure 6 months after renal denervation (Lancet 2010;376:1903-9).
Patients in the new study had their blood pressure fall by substantially less than in the Symplicity HTN-2 study, by an average of 12.5/7.5 mm Hg after 6 months in the new study, compared with 32/12 mm Hg in the renal denervation arm of Symplicity HTN-2. However, the smaller reduction was expected because patients in the new study entered treatment with much lower blood pressures than did patients in the older trial.
"The lower the starting blood pressure, the less the response" to renal denervation, explained Dr. Schmieder, professor and head of the clinical research center of hypertension and vascular medicine at University Hospital in Erlangen, Germany. Several years of study on the effect of renal denervation clearly established this relationship, he noted.
The new study enrolled patients with a mean age of 64 years who all underwent standard renal denervation treatment using the Symplicity Flex system. The procedures produced no complications, and in addition to reducing office blood pressure measurements, the treatment produced an average reduction in heart rate of 4 bpm after 6 months. The reported changes in blood pressure occurred even though 37% of the patients in the study reduced their antihypertensive treatment regimen, despite instructions from their physicians to continue their usual treatment dosages. Moreover, none of the patients received an increase in their hypertension treatment medications during follow-up, Dr. Schmieder said.
"Our data are encouraging" for using renal denervation to treat moderate treatment-resistant hypertension, he concluded. Researchers will soon start a multicenter, controlled study to more definitively assess the safety and efficacy of renal denervation in patients with resistant hypertension with systolic blood pressures of 140-159 mm Hg, Dr. Schmieder said.
The study received no commercial support. Dr. Schmieder said he has been a consultant to and has received research support from Medtronic, the company that markets the Symplicity renal denervation systems.
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