DECEMBER 13, 2010
Nerve Zap in Kidneys May Relieve Hypertension
Stubborn blood pressure in heart patients was remarkably affected by an innovative way to eliminate kidney nerves, according to Australian research published in The Lancet. The process involves distributing radiofrequency energy to sympathetic nerves of the kidney.
Researchers believe this approach could yield positive results for heart disease while possibly lowering patients’ death risk. The study, presented at the American Heart Association Scientific Sessions 2010, was funded by Ardian, the company that produces the catheter used for the process.
“This is an extremely important study, and it has the potential for really revolutionizing the way we deal with treatmentresistant hypertension,” said Suzanne Oparil, MD, director of the Vascular Biology and Hypertension Program at the University of Alabama at Birmingham.
About 15% of the hypertensive population is faced with treatment-resistant high blood pressure, meaning their blood pressure cannot be controlled with a full dose of 3 drugs. This condition carries a high cardiovascular risk, explained Dr. Oparil.
Previous studies have suggested that the kidney’s sympathetic nerves are activated in patients with hypertension, said study author Murray Esler, MD, a cardiologist and scientist at the Baker IDI Heart and Diabetes Institute in Melbourne, Australia.
For the recent study, Dr. Esler and colleagues recruited approximately 100 participants, aged 18 to 85 years, whose treatment- resistant hypertension had failed to respond to at least 3 drugs. Patients in the treatment group had the breakthrough procedure while continuing medication therapy; those in the control group only received medications.
The procedure caused blood pressure to drop dramatically by 32/12 mm Hg. Researchers also found it to be safe, with no kidney damage or blood clots during the 6-month span of the study.
Hypertension in Children Linked to Learning Disabilities
Children with hypertension are more likely to have learning disabilities that impact attention span, working memory, and cognitive function, according to the results of a study conducted at the University of Rochester Medical Center (URMC) and published online in Pediatrics.
“The objective was to determine whether children with sustained primary hypertension are at increased risk for learning disabilities (LDs), as a school-related manifestation of neurocognitive problems,” wrote lead author Heather Adams, PhD, of the Departments of Neurology and Pediatrics, URMC, Rochester, New York.
The study was unique in its inclusion of attention deficit hyperactivity disorder (ADHD) as an LD. Previous studies have excluded participants with the disorder due to the ability of ADHD medications to raise blood pressure. Dr. Adams and colleagues believe hypertension could be a contributing cause of ADHD. The study participants included 201 children, aged 10 to 18 years, who had been referred to a hypertension clinic. LDs were observed in 37 children (18%)—among those with confirmed hypertension, a full 28% had LDs, compared with only 9% of children without hypertension.
The results do not indicate a direct causal relationship between hypertension and LDs; however, they do carry significance for caregivers of hypertensive children, Dr. Adams said.
“These findings add to the growing evidence for an association between primary hypertension and cognitive function, and may inform treatment and monitoring decisions for these children who may be at risk for learning problems,” she concluded.
No Significant Risk of Cancer Due to Antihypertensive Drugs
A comprehensive meta-analysis published in The Lancet Oncology casts doubt on the alleged cancer-causing effects of antihypertensive drugs. In a literature review of 70 controlled clinical trials, researchers found no link between cancer risk and antihypertensive drug use.
The trials included in the review covered 324,168 patients in 148 comparative treatment groups. To be eligible for the study, reports had to have compared antihypertensive drugs in at least 200 patients, examined patients for at least 1 year, and reported cancer and cancer-related mortality.
Because the combination of ACE-inhibitors plus angiotensin receptor blockers has been thought to increase cancer risk, researchers analyzed these findings separately. There was, however, no considerable risk associated with the drug combination.
The notion that these drugs increase cancer risk may be rooted in the overlapping risk factors for hypertension and cancer, the authors said. Based on their analysis, they ruled out even a 5% to 10% relative increase in cancer risk for individual classes of antihypertensive drugs. PT