Healthcare

Connections: Refining renal denervation to solve hypertension | Winter 2020

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From the OHSU Knight Cardiovascular Institute

Harsh Golwala, M.D.

Dr. Golwala is an interventional cardiologist with experience in renal denervation through his work in the SIMPLICITY HTN-3 trial. He has brought the therapy to Oregon, and is the only clinician offering it in the Pacific Northwest.

High blood pressure is the No. 1 cause of morbidity and mortality, so to counteract it, people often take multiple medications. But these medications are not cures, and we need new therapies to address high blood pressure.

Pioneered in the 1950s, renal denervation or RND is a minimally invasive procedure that uses radiofrequency ablation to selectively burn nerves in the renal arteries. This process causes a reduction in nerve activity, which decreases blood pressure. OHSU is currently enrolling patients in the SPYRAL HTN trial, a refined RND approach based on lessons learned from the SIMPLICITY HTN-3 trial several years ago.

There are three key differences in this latest trial:

  • Targeting of the branching arteries in addition to the main renal artery for ablation.
  • Using an improved catheter to ensure good contact to deliver more precise energy.
  • Targeting of a younger, healthier population taking fewer than three blood pressure medications.

SPYRAL Trial underway to reduce blood pressure via RND

RND is only available through clinical trial in the U.S. OHSU performed the first RND procedure in the Pacific Northwest last November. OHSU and Stanford Health Care are the only two centers on the West Coast enrolling patients for this pivotal trial.

In this randomized sham versus RND trial, 67% of patients will get RND. We will disclose at six months, and patients receiving the sham can opt to proceed with RND. In the 2018 feasibility study, patients receiving RND had between a 2-12  mmHG reduction in blood pressure (with an average of 7 mmHG) at six months post-procedure. The safety results showed no damage to renal arteries.

For the procedure, patients are sedated. They go home the next day, and can resume activities within a couple of days. There is a rigorous follow-up with patients at checkpoints of one month, three months and six months. For trial accuracy and safety, we are not able to enroll anyone on chronic pain medications or dialysis. A previous heart attack or stroke within the last three months is also contraindicated.

Potential benefits for the right patients

Because of research work in the 1950s, we know the RND stops high blood pressure. That early research proved that severing the nerves from the spine to the kidney eliminated high blood pressure, but at a cost of side effects. From the SIMPLICITY HTN-3 trial in 2014, we learned that patients whose disease has progressed to requiring five or more blood pressure medications will not benefit. Further research continues to narrow and refine the right technical aspects with the right patient population.

By targeting a population taking fewer than three medications, we hope the study will provide long-term blood pressure control and reduce or remove dependence on medication. Because compliance is a variable in uncontrolled blood pressure, RND could especially benefit patients who don’t like to take pills or who have other reasons for not taking medicine.

When to refer

  • Patients whose systolic pressure is between 150-180, and diastolic pressure is 90 or above.
  • Patients taking one to three medications to maintain blood pressure.
  • Patients in an age range of 40-69.
  • Patients with side effects to medications.
  • Patients with a family history of renal failure due to high blood pressure.
  • Patients with compliance issues.

Contact us

The OHSU Knight Cardiovascular Institute offers the full spectrum of care for cardiovascular disease. We are available to answer questions about all treatment options.

Please call the OHSU Physician Advice and Referral Service at 503‑494‑4567.

To refer a patient, please fax to 503‑346‑6854.