SPYRAL HTN-OFF MED Pivotal: Efficacy of Catheter-Based Renal Denervation in the Absence of Antihypertensive Medications

ACC 2020 Scientific Sessions Virtual Event - read this report by Mirvat Alasnag

The SPYRAL HTN-OFF MED Pivotal trial is a sham controlled randomized study examining the efficacy and safety of renal artery denervation (RDN) compared to a sham group, and the primary endpoint was the reduction in the blood pressure of subjects with uncontrolled hypertension not on antihypertensive therapy.

This sham controlled randomized study examined the efficacy and safety of renal artery denervation (RDN) compared to a sham group. Reduction in the blood pressure of subjects with uncontrolled hypertension not on antihypertensive therapy was the primary endpoint. Patients who were not on antihypertensive medication or those in whom drug therapy could be discontinued were enrolled. An office systolic blood pressure ≥150 and <180 mm Hg, office diastolic blood pressure ≥90 mm Hg, systolic 24-hour mean ambulatory blood pressure monitoring ≥140 and <170 mm Hg were the inclusion criteria. Those with ineligible renal artery anatomy, estimated glomerular filtration rate <45 ml/min/1.73 m2, Type 1 diabetes or type 2 diabetes with glycated hemoglobin A1c >8.0% and secondary hypertension were excluded. The total number enrolled was 331 (RDN 166 and sham 165).

Baseline Findings:

Parameter	Value
Baseline office systolic blood pressure	163 mmHg
Baseline office diastolic blood pressure	101 mmHg
Baseline 24-hour mean systolic blood pressure	151 mmHg
Baseline 24-hour mean diastolic blood pressure	98 mmHg
Total ablations/patient	47

Principal Findings (Co-primary outcomes at 3 months)

Parameter	RDN	Sham
Change in 24-hour systolic blood pressure (p < 0.001)	-4.7 mmHg	-0.6 mmHg
Change in 24-hour diastolic blood pressure (p < 0.001)	-3.7 mmHg	-0.8 mmHg
Change in office systolic blood pressure (p < 0.001)	-9.2 mmHg	-2.5 mmHg
Change in office diastolic blood pressure (p < 0.001)	-5.1 mmHg	-1.0 mmHg

Secondary Outcomes:

Parameter	RDN	Sham
Proportion of patients placed on antihypertensive therapy due to systolic blood pressure >180 mm Hg or for safety reasons (p = 0.049)	9.6%	17%
Major adverse events: death, stroke, changes in kidney function or injury to the renal arteries	0.6%	0%

Renal artery denervation associated with a significant reduction in blood pressure in individuals not on antihypertensive medications.. but the short follow-up period a limitation of the study

Sham controlled trials provide the most reliable evidence for any technology. In this study renal artery denervation was associated with a significant reduction in blood pressure in individuals not on antihypertensive medications compared to the placebo arm.

There were no safety concerns from this invasive procedure. What does that mean? RDN is a safe alternative to medications when adherence is questionable. Results suggest blood pressure reduction is not just during the day but also through the night and early morning periods when the risk for cardiovascular events is highest. Of course, the short follow-up period is a limitation of this study.

It is difficult to know whether the results are sustainable beyond the 3-month period. It is also difficult to ascertain whether results are applicable to higher risk individuals with multiple risk factors, type 1 diabetes, resistant hypertension and advanced cardiac diseases.

Finally, in real life many patients are already on antihypertensive medications for other indications (eg ACE-inhibitors for left ventricular systolic dysfunction). Such patients were excluded from this study and no further conclusions can be drawn particularly as the goal in heart failure is to increase medications to the maximum tolerated doses. The added value of RDN in a cohort on medications is still under investigation in the SPYRAL-HTN ON MED trial which is expected in another 18 months.

Image 1: Reduction in all BP measurements with RDN

Image 2: RDN showing sustained reduction in BP over the 24 hours

Related tweet from #SCAI2020 Virtual:

#ACCIC #SCAI2020

Options for Hypertension
#RDN SPYRAL on & off meds
ReCor Global Program
Alcohol ablation @AnastasiaSMihai @AtulPathak31 @SABOURETCardio @PCRonline review https://t.co/q4DFZvlHJ6 pic.twitter.com/PAvKYQGNe8
— MIЯVΛƬ #StaySafe (@mirvatalasnag) May 15, 2020

Author

Mirvat Alasnag

@mirvatalasnag

Interventional cardiologist / Cardiologist

Jeddah, Saudi Arabia

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