Renal denervation effective for uncontrolled hypertension in patients not taking medications
Renal denervation is efficacious in reducing blood pressure in adult patients with uncontrolled hypertension not taking any medications, according to late-breaking results from the SPYRAL HTN-OFF MED study presented at the European Society of Cardiology Congress 2017 (ESC 2017) held in Barcelona, Spain.
The international, multicentre, prospective, randomized, sham-controlled study included 80 patients who were drug-naive or had discontinued antihypertensive maintenance therapy. Results showed more significant reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) at 3 months, as measured by 24-hour ambulatory blood pressure monitoring (ABPM), in the renal denervation vs sham control group (SBP, -5.5 vs -0.5 mm Hg [p=0.04]; DBP, -4.8 vs -0.4 [p=0.002]). [Lancet 2017, doi: http://dx.doi.org/10.1016/S0140-6736(17)32281-X]
The renal denervation group also showed more significant reductions in office SBP and DBP at 3 months vs the sham control group (SBP, -10.0 vs -2.3 mm Hg [p=0.02]; DBP, -5.3 vs -0.3 [p=0.008]).
“SYMPLICITY HTN-3, a predecessor trial, failed to demonstrate significant blood pressure lowering with renal denervation. The novelty of the SPYRAL HTN-OFF MED trial is we went into the [main renal artery] branches and treated an average of 5.2 branches per patient. We also did an average of 17.9 main artery ablations and 25.9 branch ablations per patient,” commented investigator Professor Michael Boehm from the University of Saarland in Homburg/Saar, Germany. [J Am Coll Cardiol 2015;65:1314-1321]
“Other differences from the SYMPLICITY HTN-3 trial include the absence of antihypertensive drugs at the time of randomization, and implementation of drug adherence testing in serum and urine to avoid interference of drug effects on the procedure. Furthermore, patients with isolated systolic hypertension [ISH] were excluded from the trial as they could be hyporesponsive to renal denervation procedures,” added Boehm.
“The procedure in the SPYRAL HTN-OFF MED trial involved the use of a four-electrode, simultaneous ablation system to assure circumferentiality, in contrast to the mono-electrode, sequential ablation system used in the SYMPLICITY HTN-3 trial,” he continued.
“In SPYRAL HTN-OFF MED, the procedure was performed by more highly experienced operators who did an average of 43.8 ablations per patient, as compared with an average of 11.2 ablations per patient in the SYMPLICITY HTN-3 trial,” he pointed out.
“The study provided biologic proof of principle for the efficacy of renal denervation, demonstrating clinically meaningful blood pressure reductions and no major safety events, which may pave the way for designing larger pivotal trials,” Boehm concluded.
“The main caveat in the study is predicting which patients will respond because of the variations observed in mean blood pressure response despite a standardized treatment delivery with multi-electrodes… The study population excluded patients with ISH, the most common and the most difficult to treat hypertension phenotype,” commented discussant Professor Bryan Williams of the University College London, UK.