Abaixo temos uma matéria publicada no site MedPage Today, a qual refere-se a um trabalho apresentado no Simpósio da Associação Europeia para o Estudo do Diabetes.
Destroying the nerves of the kidney's main arteries in order to treat resistant hypertension also appears to have some effects on glucose levels in the blood, researchers said here.
In nondiabetics, early trials of renal denervation have shown improvements in fasting insulin and glucose levels, and reductions in C-peptide, a marker of beta-cell function, Felix Mahfoud, MD, of Saarland University in Germany, said during a symposium at the European Association for the Study of Diabetes meeting.And in a small trial that included diabetic patients, Mahfoud said he and colleagues observed similar improvements in glycemic parameters after using renal denervation to treat resistant hypertension.
"The question remains open as to when the procedure should take place" in diabetic patients, Mahfoud told MedPage Today. "Should it be preventive, to stop progression from hyperinsulinemia to frank diabetes, or should it be a therapeutic approach for type 2 diabetics [who are] even on insulin?"
The therapy, which involves using a catheter to ablate the sympathetic nerves of the renal artery with radiofrequency energy, is intended for patients who have resistant hypertension – that is, hypertension that won't dip below 140/90 mm Hg despite the use of three or more antihypertensive agents.
Researchers say about 10% of the treated population has this challenging type of high blood pressure.
The treatment has earned a CE mark for the indication in the European Union but is not approved in the U.S.
Yet some clinicians are hesitant to use the technology in refractory hypertension, let alone in diabetics, because there hasn't been long-term safety and efficacy follow-up.
"Some cardiologists feel it is overused, [being done] in too many patients without having [more] data," Viktor Joergens, MD, executive director of EASD, said during a press briefing.
Thomas Pieber, MD, of the Medical University of Graz in Austria, said the lack of long-term data is an example of troubles in European device regulation, a hot-button issue at this year's meeting.
"If this were a drug, there would have been randomized controlled trials indicating that it could ... reduce hypertension to a certain amount," Pieber said during the briefing. "It sounds like a good idea, but we have no idea what the long-term consequences are, and yet we are still allowed to use it."
In the U.S., the FDA called for phase III randomized controlled trials before it considers approving Medtronic's Symplicity renal denervation catheter. A total of 120 patients will be randomized 2:1 to either treatment or a sham procedure, researchers said.
The therapy is generally suited for those who can't get their high blood pressure below 160 mm Hg with three or more drugs, Mahfoud said. Diabetic patients who can't get their pressure below 150 mm Hg with that amount of agents would also be eligible, he added, as long as they have preserved renal function with an eGFR ≥45 mL/min/1.73 m2, and no stenosis or stenting in their renal arteries.
The downside of therapy is that it's painful, he explained, and that interventionalists don't have an exact readout as to whether they are indeed ablating sympathetic nerves, which are challenging to image and measure.
Also, once those nerves are cut off, researchers question whether they can regrow. But Mahfoud noted that so far, 3 years' worth of data have shown no signs of renal nerve regrowth.
In addition, about 20% of patients don't respond to the therapy, though researchers aren't sure whether "the procedure isn't working, or if it's a type of hypertension that's resistant to the manipulation of sympathetic nerves," Mahfoud told MedPage Today.
Nor are researchers sure about the exact mechanism by which knocking out renal nerves improves hypertension and glycemia.
Custoefetividade e eficácia clínica da denervação renal por cateter para o tratamento da hipertensão arterial resistente
Cost-Effectiveness and Clinical Effectiveness of Catheter-Based Renal Denervation for Resistant Hypertension
Objectives: The purpose of this study was to assess cost-effectiveness and long-term clinical benefits of renal denervation in resistant hypertensive patients.
Background: Resistant hypertension affects 12% of hypertensive persons. In the Symplicity HTN-2 randomized controlled trial, catheterbased renal denervation (RDN) lowered systolic blood pressure by 32 23 mm Hg from 178 18 mm Hg at baseline.
Methods: A state-transition model was used to predict the effect of RDN and standard of care on 10-year and lifetime probabilities of stroke, myocardial infarction, all coronary heart disease, heart failure, end-stage renal disease, and median survival. We adopted a societal perspective and estimated an incremental cost-effectiveness ratio in U.S. dollars per quality-adjusted life-year, both discounted at 3% per year. Robustness and uncertainty were evaluated using deterministic and probabilistic sensitivity analyses.
Results: Renal denervation substantially reduced event probabilities (10-year/lifetime relative risks: stroke 0.70/0.83; myocardial infarction 0.68/0.85; all coronary heart disease 0.78/0.90; heart failure 0.79/0.92; end-stage renal disease 0.72/0.81).Median survival was 18.4 years for RDN versus 17.1 years for standard of care. The discounted lifetime incremental cost-effectiveness ratio was $3,071 per quality-adjusted life-year.
Findings: Were relatively insensitive to variations in input parameters except for systolic blood pressure reduction, baseline systolic blood pressure, and effect duration. The 95% credible interval for incremental cost-effectiveness ratio was cost-saving to $31,460 per quality-adjusted life-year.
Conclusions: The model suggests that catheter-based renal denervation, over a wide range of assumptions, is a cost-effective strategy for resistant hypertension that might result in lower cardiovascular morbidity and mortality. (J Am Coll Cardiol 2012;xx:xxx) © 2012 by the American College of Cardiology Foundation.
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