The SPYRAL HTN-ON MED trial did not meet its primary endpoint of reducing 24-hour ambulatory systolic blood pressure (SBP) by radiofrequency renal denervation (RF-RDN) in hypertensive patients on antihypertensive medications.
Dr David Kandzari (Piedmont Heart Institute, GA, USA) and co-investigators conducted the international sham-controlled SPYRAL HTN-ON MED trial (NCT02439775) to investigate the efficacy and safety of RF-RDN in patients with uncontrolled hypertension on antihypertensive medications . 337 participants with an SBP between 150 and 180 mmHg were randomised 2:1 to RF-RDN plus antihypertensive medication or a sham procedure plus antihypertensive medication. The primary efficacy outcome was the change in 24-hour ambulatory SBP at 6 months and the primary safety endpoint was the major adverse event (MAE) rate at 1 month.
Only 1 MAE (0.4%) was reported after 1 month in the RF-RDN arm, meeting the performance goal of 7.1% (P<0.001). With a reduction of 6.5 mmHg in 24-hour SBP in the intervention arm and a reduction of 4.5 mmHg in the control arm, the anticipated difference in the primary efficacy endpoint was not met (P=0.12). In contrast, the reduction of office SBP (-9.9 vs -5.1; P=0.001) and office diastolic BP (-5.2 vs -3.3; P=0.04) at 6 months was more pronounced in the RF-RDN compared with the control arm (see Figure). A win ratio analysis of 24-hour SBP and medication burden reduction demonstrated a benefit of the RF-RDN arm over the control arm, with a win ratio of 1.50 (P=0.005).
Figure: Blood pressure changes at 6 months of RF-RDN treatment in the presence of antihypertensive drugs 
ABPM, ambulatory blood pressure monitoring; RDN, renal denervation; BP, blood pressure; Δ, difference.
Dr Ajay Kirtane (Columbia University Irving Medical Center, NY, USA) presented the results of the trial. “We know that medications to lower blood pressure work. Any trial attempting to isolate the effect of RF-RDN versus sham should therefore aim to keep the administration of antihypertensive medication at the same level in both treatment arms,” he argued. Data from the SPYRAL HTN-ON MED trial showed that the amount of medication given and medication burden was significantly increased in the control arm compared with the intervention arm at 6 months. “Despite missing its primary endpoint, I think that the SPYRAL HTN ON-MED trial confirmed that RF-RDN lowers BP. It is just difficult to isolate the effect of RF-RDN in on-medication trials,” Dr Kirtane closed.
- Kandzari DE, et al. Effect of radiofrequency renal denervation on blood pressure in the presence of antihypertensive drugs: 6-month primary results from the SPYRAL HTN-ON med expansion randomized trial. LBS.09, AHA Scientific Sessions 2022, 05–07 November, Chicago, USA.
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