By Jan Staessen
Hypertension affects an estimated 20% to 30% of the world’s adult population.1 Despite the availability of numerous safe and effective pharmacological therapies, including single pill combinations of two to three drugs, the percentage of patients achieving adequate blood pressure control meeting guideline targets remains low.1,2
Resistant hypertension is a blood pressure that remains above goal in spite of the concomitant use of antihypertensive medications from ≥3 drug classes.3 Patients who require more than four drug classes to have their blood pressure controlled are also considered to have resistant hypertension. Preferably, the regimen should include a diuretic, and all of the doses should be optimal.3,4
The SYMPLICITY5-7 studies recently demonstrated that reducing sympathetic tone by intravascular renal denervation is feasible in patients with resistant hypertension. However, these studies did not provide conclusive evidence of the size and durability of the antihypertensive, renal and sympatholytic effects and they also did not provide evidence of long-term safety, quality of life, the possibility to reduce or stop antihypertensive drug treatment, cost-effectiveness, and benefit in terms of long-term hard cardiovascular-renal outcomes. At the time of writing of this report, more than 30 renal denervation trials, for various indications, were registered at www.clinicaltrials.gov, but only few have a randomised controlled design.
In the USA, renal denervation remains an investigational procedure that cannot be used in clinical practice. However in Europe, CE-label certification of electrical safety allow companies to market catheter systems to any interventional facility for regular clinical use.
Renal denervation should not be routinely applied as a substitute for the skilful management of resistant patients, which includes documentation of adherence to antihypertensive drugs, implementation of lifestyle measures, and the use of recommended combinations of antihypertensive agents at the highest tolerated daily dose. For now, therefore, the procedure should remain the ultima ratio in adherent patients with severe resistant hypertension,8 in whom all other efforts to reduce blood pressure have failed. Renal denervation should only be offered within a clinical research context at highly skilled tertiary referral centres that participate in international registries constructed independent of the industry.
Future research on renal denervation as a way to treat hypertension should address unresolved issues, such as the size and durability of the antihypertensive, renal, and sympatholytic effects; long-term safety; quality of life; the possibility to taper antihypertensive drug treatment after the procedure; cost-effectiveness; and, above all, the long-term benefit in terms of hard cardiovascular-renal outcomes.8
Jan A Staessen, Division of Hypertension and Cardiovascular Rehabilitation, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
References
1. Staessen et al. JAMA 2003; 289: 2420–22
2. Weinehall et al. J Hypertens 2002; 20: 2081–88
3.Calhoun et al. Circulation 2008; 117: e510–26
4. Fagard. Heart 2012; 98: 254–61
5. Krum et al. Lancet 2009; 373: 1275–81
6. Symplicity HTN–2 Investigators. Lancet 2010; 376: 1903–09
7. Symplicity HTN–1 Investigators. Hypertension 2011; 57: 911–17
8. Persu A, Renkin J, Thijs L, Staessen JA. Hypertension 2012; 60: 596-606
