Catheter-based renal denervation for treatment of patients with treatment-resistant hypertension: 36 month results from the SYMPLICITY HTN-2 randomized clinical trial

AIM

The aim of this study was to determine long-term results of renal artery denervation for treatment of treatment-resistant hypertension in the SYMPLICITY HTN-2 study.

METHODS

SYMPLICITY HTN-2 randomized 106 subjects with treatment-resistant hypertension to renal denervation or medical therapy alone. At 6 months, 37 control subjects crossed over to renal denervation. Office blood pressure measurements, antihypertensive medication use, and safety events were followed every 6 months through 3 years.

RESULTS

Follow-up was available at 36 months in 40 of 52 subjects in the initial renal denervation group and at 30 months in 30 of 37 subjects who crossed over and received renal denervation at 6 months. Baseline blood pressure was 184 ± 19/99 ± 16 mmHg in all treated subjects. At 30-month post-procedure, systolic blood pressure decreased 34 mmHg (95% CI: -40, -27, P < 0.01) and diastolic blood pressure decreased 13 mmHg (95% CI: -16, -10, P < 0.01). The systolic and diastolic blood pressure reduction at 36 months for the initial renal denervation group was -33 mmHg (95% CI: -40, -25, P < 0.01) and -14 mmHg (95% CI: -17, -10, P < 0.01), respectively. Procedural complications included one haematoma, and one renal artery dissection before energy delivery that was treated successfully. Later complications included two cases of acute renal failure, which fully resolved, 15 hypertensive events requiring hospitalization, and three deaths.

CONCLUSION

Renal denervation resulted in sustained lowering of blood pressure at 3 years in a selected population of subjects with severe, treatment-resistant hypertension without serious safety concerns.

CLINICAL TRIAL REGISTRATION

NCT00888433.

Orthostatic function after renal sympathetic denervation in patients with resistant hypertension

INTRODUCTION

Catheter-based renal denervation (RDN) reduces local and whole-body sympathetic activity and blood pressure (BP) in patients with resistant hypertension. However, safety concerns exist concerning the development of orthostatic dysfunction after RDN.

METHODS AND RESULTS

In 36 patients (65 ± 7.6 years, 75% male) with resistant hypertension (office BP 162 ± 24/91 ± 14 mm Hg) treated with 4.8 ± 1.7 antihypertensive drugs, tilt table testing (TTT) was performed before and three months after RDN. Response to RDN was defined as a reduction in office systolic BP (SBP) ≥ 10 mm Hg three months after RDN. Responders (n=26; 72.2%) and non-responders (n=10; 27.8%) were evaluated separately. After RDN, office SBP and diastolic BP (DBP) were reduced by 29 ± 6.2/14 ± 3.6 mm Hg (p<0.0001; p=0.0002) only in responders. During TTT, SBP and DBP in supine position were only reduced in responders. Resting heart rate (HR) decreased in responders but not in non-responders by 5.9 ± 1.7beats/min (p=0.0016). Mean and minimal SBP were not altered during passive tilting. In the responder group, ∆SBP was reduced in the initial phase of tilting. The adaptive increase of HR was preserved in both groups after RDN, while only in responders mean and minimal HR were reduced after passive tilting. Following drug provocation, mean and minimal SBP during all phases of passive tilting remained unchanged. ∆SBP, ∆HR and total number of (pre-)syncopes were neither influenced by RDN nor differing between responders and non-responders.

CONCLUSIONS

In patients with resistant hypertension, RDN reduced office BP, supine BP and HR during TTT without causing orthostatic dysfunction or (pre-)syncopes three months after treatment.

Catheter-based Renal Sympathetic Denervation - Long-term Symplicity™ Renal Denervation Clinical Evidence, New Data and Future Perspectives

Hypertension is one of the most prevalent chronic diseases worldwide and the incidence of resistant hypertension is increasing. Catheter-based renal denervation (RDN) offers a new approach to reaching blood pressure goals by targeting the renal nerves. The technique has demonstrated significant and sustained reductions in blood pressure (BP) in the Symplicity HTN-1 and Symplicity HTN-2 clinical trials. The Global SYMPLICITY Registry aims to demonstrate safety and effectiveness in a 'real-world' patient population. Real-world RDN experience has emphasised that patient selection is crucial to successful outcomes; a multidisciplinary referral network is recommended to increase awareness of the procedure and identify patients who are likely to respond best to RDN. Further advances in catheter technology have led to the development of the multi-electrode Symplicity Spyral™ multi-electrode catheter; preliminary data from the feasibility study using the Symplicity Spyral catheter indicate clinical efficacy and procedural safety with reduced procedure times. The Symplicity Spyral catheter is not yet commercially available. The indications of RDN may also expand beyond resistant hypertension - encouraging data have been seen in patients with moderate treatment resistant hypertension. Furthermore, RDN may be beneficial in other clinical states characterised by sympathetic nervous system overactivation including heart failure and chronic kidney disease. Additional data are needed to evaluate the efficacy of RDN in these disease states.