A Medtronic Inc. (MDT) device used to control hard-to-treat high blood pressure by burning overactive nerves with a burst of radio-frequency energy helped reduce the condition in 24 patients over three years in a study.
The device, dubbed Symplicity, is threaded using a catheter from an artery in the groin to nerves that lead to the kidneys. They were then seared to disable them in 153 patients with drug- resistant hypertension, the form seen in a third of those with the disease, or about 120 million people worldwide.
After six months, 71 percent improved in the study, funded by Minneapolis-based Medtronic and reported at the American College of Cardiology meeting in Chicago. Two dozen patients who were followed for three years all recorded lower blood pressure after the procedure, which is approved for sales abroad. Studies needed to obtain U.S. clearance are under way.
“As the duration of follow-up in these Symplicity clinical trials grows, so too does our confidence in the enduring safety and effectiveness,” said George Bakris, director of the hypertension center at the University of Chicago and president of the American Society of Hypertension, in a statement.
People with untreated high blood pressure, or hypertension, are at greater risk for heart attack, stroke, kidney disease and death, according to Medtronic. Overactivity in the sympathetic nerve system near the kidneys seems to help initiate and sustain hypertension and may affect salt and water retention, according to an October, 2009, report in the journal Hypertension.
‘Longest Term Data’
The latest research is “the longest term data to date involving renal denervation,” said Bakris, who is running one of Medtronic’s studies on the device.
Patients treated with the Medtronic system saw their systolic blood pressure, the top number measured when the heart contracts, plunge by 33 millimeters of mercury after three years. Their diastolic pressure, when the heart fills with blood, fell by 19 mmHg, the data shows.
Previous studies show treatment with medications reduce diastolic pressure by 5 mmHg decline, cut heart disease risk by 15 percent and strokes by 42 percent.
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