Catheter-based renal denervation is effective in reducing blood pressure in the absence of antihypertensive medications, according to late-breaking trial results presented Sunday at the American College of Cardiology Scientific Sessions 2020 virtual conference.
Michael Böhm, MD, of University of Saarland, Germany, presented results from the SPYRAL HTN-OFF MED study.
Currently, 1 in 3 adults have hypertension, and there is an unmet need for hypertension treatment. The initial SPYRAL HTN-OFF MED pilot trial showed that renal denervation (RDN) effectively reduces blood pressure, thus leading to this pivotal trial.
The Symplicity Spyral catheter is a 6-French compatible, multi-electrode catheter with a quadrantic vessel contact for simultaneous ablation in up to 4 electrodes. Flexibility of the catheter allows for branch treatment.
SPYRAL HTN-OFF MED is a prospective, multicenter, randomized, sham-controlled study performed in 44 recruiting sites worldwide. All the patients were screened during two office visits, separated 3 to 4 weeks apart, to check office blood pressure and for drug testing. The main inclusion criteria were patients with confirmed elevated blood pressure as per guidelines and not on antihypertensive medications, and the main exclusion criteria were patients with ineligible renal artery anatomy, type 1 diabetes mellitus, estimated glomerular filtration rate <45 mL/min/1.73 m2, secondary causes of hypertension and patients with systolic blood pressure (SBP) >180 mmHg or diastolic blood pressure (DBP) <90 mmHg.
A total of 251 patients were randomized to receive RDN or a sham procedure. Follow-up was performed every 2 weeks. The primary efficacy endpoint was change in 24-hour SBP/DBP and office SBP/DBP at 3 months. The primary safety endpoint was any major adverse event at 1 and 3 months.
For the primary analysis, 80 patients in the initial pilot trial were included, bringing the total to 331 randomized patients, 166 to RDN and 165 to the sham control. In the RDN group, the patients’ mean age was 52.4 years, 64.5% were men, and 3.6% had type 2 diabetes. In the control group, the mean age was 52.6 years, 68.5% were men, and 5.5% had type 2 diabetes. At baseline, office SBP was around 162 mmHg and 24-hour SBP was 151 mmHg in both groups. In the RDN group, about 2.2±0.6 renal arteries were treated and 5.8±2.7 branches were treated. A total of 46.9±15.6 ablations were performed, of which 18.3±9.9 were in the main arteries. The procedure was successful in all patients.
At 1 month, there were no major adverse events in either group. At 3 months, one patient in the RDN group was hospitalized for hypertensive crisis and one patient in the sham-control group experienced stroke. At 3 months, 91% of RDN patients had no anti-hypertensive drug identified by drug testing, compared to 95% in the sham group.
In terms of the primary efficacy endpoint, at 3 months, both office SBP and DBP were significantly lower in the RDN group (Office SBP: D-6.6 mmHg [-9.6, -3.5, p<0.001], Office DBP: D-4.4 mmHg [-6.2, -2.6, p<0.001]). Similar results were seen with 24-hour ambulatory SBP and DBP at 3 months. Treatment effects were consistent in both the pilot and pivotal trials. By Bayesian, primary endpoint analysis, RDN met the primary efficacy endpoint with >99.9% probability of superiority. The subgroup analysis showed a positive trend, though nonsignificant, with RDN reducing blood pressure in most groups. Although antihypertensive drugs were detected in 36 patients, the results were also consistent in the per-protocol analysis, which excluded patients on medications.
Böhm concluded that catheter-based RDN is effective in lowering blood pressure in patients with uncontrolled hypertension in the absence of antihypertensive medication, with no major device- or procedure-related safety events through 3 months. He added that a large study with patients on medications, SPYRAL HTN-ON MED, is currently enrolling.
The results of the SPYRAL HTN-OFF MED study were simultaneously published online in The Lancet.
The study is sponsored by Medtronic Vascular.