St. David's HealthCare

St. David's HealthCare is one of the largest health systems in Texas and Austin's
third-largest private employer, with more than 60 sites throughout Central Texas,
including seven hospitals, four urgent care centers, four ambulatory surgery centers,
and two freestanding emergency departments, with a third set to open in Bastrop this summer.

St. David's HealthCare has a long history of serving the residents of Central Texas
with exceptional medical care. Our 7,500 employees touch over 858,000 lives each
year with a spirit of warmth, friendliness and personal pride.

Visit our main website at
St. David's Medical Center (512) 476-7111
St. David's North Austin (512) 901-1000
St. David's South Austin (512) 447-2211
St. David's Round Rock (512) 341-1000
St. David's Georgetown (512) 943-3000
St. David's Rehabilitation (512) 544-5100
Heart Hospital of Austin (512) 407-7000


Heart Hospital of Austin to Participate in Landmark Study of New Approach to Treat High Blood Pressure

Clinical Trial Evaluates Investigational Approach to Treat High Blood Pressure

By Deactivating Nerves in Arterial Walls Leading to Kidneys

AUSTIN, Texas—Heart Hospital of Austin is now enrolling patients in the SYMPLICITY HTN-3 study, a clinical trial of the investigational Symplicity® renal denervation system for treatment-resistant hypertension. Treatment-resistant hypertension is defined as systolic blood pressure that remains high (greater than 140/90 mmHg) despite treatment with three or more anti-hypertensive medications.

"I am excited that this therapy is being evaluated through a clinical trial in the Austin area," Helen J. Maidment, M.D., a nephrologist with Capital Nephrology, said. "This treatment may be key for patients whose hypertension cannot be optimally controlled by other medical treatments. Additionally, medicines to treat hypertension can be costly and have undesirable side effects."

Renal denervation is a minimally invasive, catheter-based procedure that regulates the output of nerves that line the walls of the arteries leading to the kidneys. These nerves are part of the sympathetic nervous system, which is one of the ways the body controls blood pressure. In people with hypertension, the renal nerves are hyperactive, raising blood pressure and contributing to heart attack and stroke.

“We’re eager to participate in the study of this interventional treatment, which may represent a new and innovative approach to treating the growing number of resistant hypertension patients in the United States,” said Frank Zidar, M.D., principal investigator and interventional cardiologist with Austin Heart who practices at Heart Hospital of Austin. “Renal denervation and ongoing treatment with anti-hypertensive medications have the potential to help patients with this challenging form of hypertension achieve their target blood pressure levels. Controlling blood pressure clearly impacts an individual’s risk of stroke and heart attack.” 

The renal denervation system is a flexible catheter and an energy generator. The Symplicity® catheter is introduced through the skin into the femoral artery, located in the upper thigh, and is then threaded up into the renal artery leading to each kidney. It is connected to the Symplicity® generator, which produces controlled, low-power radio-frequency (RF) energy. 

Once within the renal artery, the tip of the Symplicity catheter is placed against the arterial wall in several places where it uses controlled, low-power RF energy to deactivate the renal nerves according to a proprietary, computer-controlled algorithm. The treatment does not involve a permanent implant and is performed under conscious sedation.

SYMPLICITY HTN-3 is a randomized, controlled trial that will enroll approximately 530 treatment-resistant hypertension patients across several U.S. medical centers. People receiving the investigational treatment will be compared with a control group that does not, with all patients continuing to take their blood pressure medications. Patients enrolled in the SYMPLICITY HTN-3 trial will be randomly assigned to a group, with two out of three assigned to the treatment group and one out of three assigned to the control group. In addition, those in the control group may receive the treatment after a six-month period passes. The primary endpoints of the study are the change in blood pressure from baseline to six months and incidence of major adverse events.  

“This study has a unique design since patients in the control group have the option to receive renal denervation treatment six months following randomization, which may extend the benefit of renal denervation to all participants in the trial,” said Dr. Zidar. 

The Symplicity renal denervation system has been successfully used since 2007 to treat more than 2,000 patients worldwide. It has been commercially available in Europe and Australia since April 2010. The Symplicity renal denervation system is not approved by the U.S. Food and Drug Administration (FDA) for commercial distribution in the United States. 

Treatment-resistant hypertension poses a serious health threat to nearly six million Americans and 100 million people worldwide. It is an especially dangerous chronic disease because of its association with increased cardiovascular risk, including stroke and heart attack, as well as heart failure and kidney disease. Research suggests that 28 percent of treated hypertensive individuals are considered resistant to treatment. Additionally, these patients have a threefold increase in the risk of cardiovascular events compared with individuals with controlled high blood pressure.

Patients can contact the Austin Heart Research Department at (512) 421-3851 for more information about the clinical trial. Prospective participants also are encouraged to visit to learn more about the SYMPLICITY HTN-3 study and their potential eligibility for the trial. Those considering participation in the trial should be diagnosed with hypertension (high blood pressure) and unable to control their hypertension even when taking three or more blood pressure medications. 

Heart Hospital of Austin

Heart Hospital of Austin, located at 3801 North Lamar Boulevard, is part of St. David’s HealthCare, one of the largest health systems in Texas, which was recognized as one of the top 15 health systems in the U.S. by Thomson Reuters in January 2012. Specializing in the diagnosis and treatment of cardiovascular disease, Heart Hospital of Austin is a shared vision of local cardiologists and cardiovascular surgeons. Working with hospital leadership, the physicians created an atmosphere of quality, resulting in the leading cardiac program in Texas for six consecutive years as ranked by HealthGrades®—a leading independent health ratings organization. In July 2009, a study funded by the Centers for Medicare and Medicaid Services revealed that Heart Hospital of Austin was the leading hospital in the United States for treatment of a heart attack. Heart Hospital of Austin has also been named a top cardiovascular hospital in the nation by Thomson Reuters for six years, most recently being named to the list of 50 Top Cardiovascular Hospitals in 2011. In addition to providing a full range of cardiovascular services and an advanced Executive Wellness Program, Heart Hospital of Austin has a comprehensive 24-hour emergency department. Heart Hospital of Austin is a St. David’s Medical Center facility. For more information, please visit

Austin Heart

Austin Heart is the largest provider of cardiac and vascular services in Central Texas, with 12 full-time office locations, 17 outreach clinics and 45 cardiologists. Austin Heart has been serving the Central Texas area since 1973. Austin Heart’s cardiologists sub-specialize in every diagnostic and treatment area of cardiovascular disease, America’s No. 1 killer—interventional cardiology, electrophysiology, congestive heart failure, peripheral vascular disease, vein disease, sleep disorders, erectile dysfunction, imaging, women’s cardiovascular health and a nationally recognized research department. To learn more about Austin Heart physicians, or to schedule an appointment, visit

HealthGrades 2012

Thomas Reuters 50 Top Cardio Hospitals 2013

Awards & Recognition

Heart Hospital of Austin named Top Cardiovascular Hospital in the nation for the 7th year by Truven Health Analytics


Heart Hospital of Austin named among the Top 5% of hospitals in U.S. for clinical excellence by HealthGrades


Heart Hospital of Austin ranked as the #1 Cardiac Program in Texas for six consecutive years by HealthGrades


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