Renal artery denervation via catheter-based delivery of low-power radiofrequency energy provides safe and durable blood pressure reduction: complete 3 year results from SYMPLICITY HTN-1

Abstract

Purpose: Ablation of nerves within the renal arteries using low power radiofrequency energy has been shown to significantly reduce blood pressure (BP) in patients with severe hypertension unresponsive to standard pharmacologic treatments. Concerns regarding the long-term safety and effectiveness of this novel therapy requires careful follow-up of patients who have undergone the renal denervation (RDN) procedure. Methods: Symplicity HTN-1, an open-label cohort study, enrolled 153 patients with treatment-resistant hypertension (systolic BP >160 mm Hg despite the use of >3 antihypertensive drugs including a diuretic). There were 144 patients consented for 2 year follow-up and 129 patients consented for 3 year follow-up Changes in office-based BP and HR, distribution of BP measurements, medication usage and safety were monitored through 3 years follow-up. Using a response criterion of >10 mm Hg reduction in systolic BP (SBP) the proportion of patients with a late (after 1 month) BP response was determined. Results: Follow-up is currently complete for 105 patients to 2 years and 34 patients to 3 years. Mean age at baseline was 57±11 years; 39% of patients were female; 31% had type 2 diabetes mellitus; eGFR was83±20 mL/min and BPwas 175/98±17/15 mmHg. Mean SBP change post-RDN was -289 mmHg (95% CI -335, -244) at 2 years and-31 3 mmHg (95% CI -365, -261) at 3 years (P<001 for both). At 3 years 41.2% of patients had a SBP <140 mm Hg and the proportion of patients with SBP > 180 mm Hg dropped from 30% to 5.9%. Among the patients with <10 mm Hg drop in SBP at 1 month, 64%, 71%, and 83% had responded at 1, 2 and 3 years follow-up respectively. There was one progression of a pre-existing renal artery stenosis and 1 new moderate stenosis requiring no treatment reported at 18 months, 2 cases of hypotension and transient renal failure (1 each at 18 and 24 months) and 3 deaths (3 days, 6 mo and 18 mo post-RDN) considered unrelated to the RDN procedure. Overall no net changes in medication usage are observed. Conclusions: BP reductions following RDN in patients with treatment-resistant hypertension persist through 2 and 3 years follow-up. A proportion of patients appear to be late responders to RDN treatment which is not explained by medication changes. Safety and efficacy data on the full completed 3 year cohort of patients will be presented.