SCAI: Model projects renal denervation’s benefits at 10 years

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 - Medtronic Symplicity renal denervation system
The Symplicity renal denervation system uses a catheter to deliver low-level radiofrequency energy through the renal artery wall. A physician inserts the catheter into the femoral artery to access the renal artery. A generator is then activated to deliver the energy.
Source: Medtronic

Renal denervation received a theoretical thumbs up at the Society of Cardiovascular Angiography and Interventions (SCAI) scientific sessions in Orlando, Fla., May 9, based on a model that predicts reduction in cardiovascular events in hypertensive patients treated with the ablation therapy. The projections need to be validated in clinical trials, the poster presenter cautioned.

Renal denervation is approved in Europe as an option for patients with treatment-resistant hypertension and is an investigation procedure in the U.S. for that indication. The percutaneous, catheter-based technique, which disrupts overactive renal sympathetic nerves, is also being explored as a possible treatment for atrial fibrillation and heart failure.

In the randomized Symplicity HTN-2 trial, renal denervation was shown to significantly lower mean systolic blood pressure at 12 months. But the long-term benefits remain in doubt.

At SCAI.13, Jan Pietzsch, PhD, CEO of Wing Tech in Menlo Park, Calif., and a consulting associate professor at Stanford University in Stanford, Calif., presented results from an analysis using a model to calculate cardiovascular events more than 10 years. The hypothetical cohort of hypertensive patients included three age groups and two pretreatment systolic blood pressure categories. Patients started treatment at ages 40, 55 or 70 and had baseline blood pressure readings of either 165 mmHg or 190 mmHg.   

The lifetime Markov simulation model incorporated patient characteristics and clinical data from Symplicity HTN-2 as well as data from the National Health and Nutrition Examination Survey. Using the model, Pietzsch et al calculated absolute event reduction and relative risk reduction.

They estimated that renal denervation therapy reduced systolic blood pressure from 165 to 135 mmHg and 190 to 150 mmHg with reductions in all age groups. The model also predicted reductions in events and risk in the three age groups and in all cardiovascular categories, including MI, coronary heart disease, stroke, heart failure and end-stage renal disease.

The 10-year absolute event reduction increased with age while the youngest group had the greatest relative risk reduction. “Pretty much across the board there are clinically meaningful reductions that we project both in terms of absolute and relative reductions of clinical events in all three age groups,” Pietzsch said in a release.  

“Clinical trials will need to be completed to validate these modeled projections,” he added.

Wing Tech is a health economics consultancy company. Pietzsch is a consultant for Medtronic, which is sponsoring the Symplicity HTN trials.

For more on renal denervation, please read “ Newest Frontier in Cardiac Care: Kidneys” in Cardiovascular Business.