Renal artery imaging through long-term follow-up after radiofrequency renal denervation: Results from the SPYRAL Clinical Program

Summary: Background: Renal denervation (RDN) safely reduces blood pressure (BP) in patients with uncontrolled hypertension. A potential long-term concern is the development of de novo renal artery stenosis (RAS) secondary to vascular injury. This study assesses the long-term vascular safety and incidence of RAS in patients treated with radiofrequency RDN from the SPYRAL HTN-OFF MED and -ON MED trials. Patients and methods: All patients underwent renal angiograms for assessment of the renal anatomy prior to randomization. Patients with RAS >50% were excluded from enrollment. At long-term follow-up (439+/−288 days), patients underwent duplex ultrasound imaging (DUS), computerized tomography angiography (CTA), and/or magnetic resonance angiography (MRA). Independent core labs evaluated all images. Clinically significant RAS was predefined as a stenosis ≥70%, confirmed by angiography. Results: A total of 610 patients were treated with RDN in the SPYRAL trials. At least one imaging modality was performed in 557 of the 610 patients (91%): 329 patients underwent DUS imaging, 230 underwent CTA, 148 underwent MRA, and 15 underwent renal angiography. With one possible exception, no clinically significant RAS was detected. No patients had renal artery reintervention. The proportion of images fulfilling pre-specified criteria for technical adequacy by the core lab was 100% (angiography), 87.5% (DUS), 80.6% (CTA), and 32.4% MRA. Conclusions: RF RDN appears to be safe, without confirmed vascular injury or RAS among 557 patients who had long-term imaging. Diagnostic utility of imaging modalities determined by specific criteria for technical adequacy for core lab evaluation was lowest with MRA and highest with DUS.