One-year data from SYMPLICITY HTN-3 confirm findings from six month analysis

September 2, 2014

Longer-term follow-up data from the SYMPLICITY HTN-3 trial confirmed both the safety and absence of clinical benefit of renal denervation, according to the 12 month results presented for the first time at ESC Congress today by Professor George L. Bakris, director of the ASH Comprehensive Hypertension Center, The University of Chicago Medicine in Chicago, Illinois.

Professor Bakris said: "The 12 month results presented today are consistent with the six month findings which were previously reported. We found that renal is safe but resulted in blood pressure reductions similar to a sham procedure."

He added: "Renal denervation has been used in with hypertension who do not respond to treatment with medication. A catheter is inserted into the kidney via the femoral artery and a device applies radiofrequency pulses to the renal arteries to damage the nerves and in theory reduce blood pressure. SYMPLICITY HTN-3 was the first trial to compare renal denervation to a sham procedure, in which patients received a surgical intervention with no denervation procedure, to account for any placebo effect."

SYMPLICITY HTN-3 included 535 patients with resistant hypertension (office systolic blood pressure [SBP] >160 mmHg) who were prescribed three or more hypertension medications, including a diuretic, from 88 medical centres in the US. Patients were randomised 2:1 to renal denervation or the sham procedure.

Patients and clinicians assessing blood pressure were blinded to the treatment patients received. They were unblinded following assessment of the six month primary endpoint. At this stage control patients could crossover to the renal denervation group if they met treatment criteria and agreed to the procedure. Of the 171 patients randomised to the sham procedure, 101 crossed over at six months and received renal denervation.

The primary efficacy endpoint was the change in office SBP from baseline to six months in the renal denervation arm (353 patients) compared to the sham control arm (171 patients). The secondary endpoint was the change in 24-hour ambulatory SBP at 6 months. The primary safety endpoint was a composite of major adverse events. As previously reported, the trial met its primary safety endpoint but did not meet its primary or secondary efficacy endpoints.

Safety and efficacy data were reported for three groups in the trial: 12 month outcomes for the original renal denervation group, six month outcomes for the crossover group, and 12 month outcomes for the non-crossover group (control subjects who did not meet inclusion criteria, specifically a SBP >160 mmHg, or did not wish to undergo renal denervation). The non-crossover group had a lower baseline SBP (176.1 mmHg) due to inclusion of subjects with SBP <160 mmHg at six months of follow up and thus can no longer serve as a comparator group for the renal denervation arms.

At 12 month follow-up, office SBP measurements were available for 320 patients in the original renal denervation arm. These patients continued to experience a decrease in office SBP (-18.9 mmHg) which represented an additional 3.6 mmHg decrease in SBP compared to the six month data.

For office BP, the researchers found that the crossover renal denervation group demonstrated a slightly larger decrease in SBP 6 months after the procedure than the original denervation group (-17.7 mmHg [n=92 patients] vs. -15.3 mmHg, respectively).

For 24-hour ambulatory BP, the crossover group experienced a mean reduction of -9.2 mmHg at six months after the procedure (n=82 patients) while the original renal denervation arm had a mean reduction of -7.6 mmHg at 12 months (n=255 patients).

The non-crossover group showed a much larger decrease in office SBP at 6 months (-32.9 mmHg) than any of the other groups, likely due to inclusion in this group of subjects who did not qualify for crossover to renal denervation due to a SBP <160 mmHg at six months. Between 6 and 12 months office SBP increased by 11.5 mmHg, bringing the net decrease in office SBP at 12 months to -21.4 mmHg.

Professor Bakris said: "The large changes in blood pressure reported in the non-crossover group are most likely due to individuals who varied their adherence to antihypertensive medications in these different time points in the trial. However, further research is needed to address the issue of medication adherence when designing these types of trials."

The rate of major adverse events at one year was 6.8% in the original renal denervation group, 6.4% in the crossover renal denervation group, and 7.2% in the non-crossover group. Professor Bakris said: "We did not find any difference in the rate of adverse events between any of the study arms, confirming the safety of the renal denervation procedure."

He concluded: "The latest results of the SYMPLICITY HTN-3 trial show that the renal denervation procedure is safe but reduces blood pressure to a similar extent as a sham procedure. Our findings cast doubt on whether , as performed in the SYMPLICITY HTN-3 trial, is useful for lowering in patients with resistant hypertension. However, despite these results, further studies using the insights obtained from this and other studies should be conducted using a sham control arm to confirm our results."

Explore further: EuroPCR 2014 session defines future horizons for renal denervation

Related Stories

EuroPCR 2014 session defines future horizons for renal denervation

May 27, 2014
During EuroPCR 2014, Felix Mahfoud, University Hospital in Homburg, Germany, and Konstantinos Tsioufis, University of Athens, Greece, reflected on the potential future role of modulation of the sympathetic nervous system ...

Renal denervation shows no benefit in resistant hypertension

March 31, 2014
Renal denervation fell short of primary and secondary efficacy goals in patients with severe resistant hypertension but did meet the primary safety endpoints, according to keenly awaited data from SYMPLICITY HTN-3 presented ...

Renal denervation achieves significant and sustained blood pressure reduction

August 27, 2012
Renal denervation leads to significant and sustained blood pressure reduction for up to 18 months in patients with treatment resistant hypertension, according to research presented at ESC Congress 2012. The new clinical data ...

Renal denervation patient registry finds low rate of adverse events

March 31, 2014
Patients with uncontrolled high blood pressure treated with renal denervation had low rates of adverse events and significant lowering of blood pressure at six months, according to a registry-based study presented at the ...

Renal denervation more successful when it includes accessory arteries

August 31, 2014
Renal denervation seems to be more successful at reducing blood pressure in patients with resistant hypertension when it includes accessory renal arteries, according to research presented at ESC Congress today by Dr Linda ...

Renal denervation treats resistant hypertension in real world patient populations

August 27, 2012
Renal denervation successfully treats patients with resistant hypertension in real world patient populations, according to a study presented at ESC Congress 2012. The findings were presented by Dr Darren Mylotte from France.

Recommended for you

Laser device placed on the heart identifies insufficient oxygenation better than other measures

September 20, 2017
A new device can assess in real time whether the body's tissues are receiving enough oxygen and, placed on the heart, can predict cardiac arrest in critically ill heart patients, report researchers at Boston Children's Hospital ...

Metabolism switch signals end for healing hearts

September 19, 2017
Researchers have identified the process that shuts down the human heart's ability to heal itself, and are now searching for a drug to reverse it.

Beta blockers not needed after heart attack if other medications taken

September 18, 2017
A new study from the University of North Carolina at Chapel Hill finds beta blockers are not needed after a heart attack if heart-attack survivors are taking ACE inhibitors and statins. The study is the first to challenge ...

Which single behavior best prevents high blood pressure?

September 15, 2017
(HealthDay)—You probably already know that certain healthy lifestyle behaviors can reduce your risk of developing high blood pressure, but is any one behavior more important than the others?

RESPECT trial shows closing a small hole in heart may protect against recurrent stroke

September 13, 2017
A device used to close a small hole in the heart may benefit certain stroke patients by providing an extra layer of protection for those facing years of ongoing stroke risk, according to the results of a large clinical trial ...

Study shows so-called 'healthy obesity' is harmful to cardiovascular health

September 11, 2017
Clinicians are being warned not to ignore the increased cardiovascular health risks of those who are classed as either 'healthy obese' or deemed to be 'normal weight' but have metabolic abnormalities such as diabetes.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.