Systematic screening should identify those eligible for percutaneous renal denervation

Verloop WL, Vink EE, Voskuil M et al.
J Hypertens. 2013 Jun 5. [Epub ahead of print]

Background

The prevalence of hypertension is around 34% globally and rising [1]. Hypertension is a modifiable risk factor, although treatment goals are often not met [2].
Increased activation of the sympathetic nervous system has been recognized to contribute to hypertension [3]. The renal sympathetic nerves can be disrupted using radiofrequency energy in a percutaneous, catheter-based approach [4]. The first clinical studies show that bilateral percutaneous renal denervation (pRDN) can safely lower SBP/DBP values [5-7].
The European Society of Hypertension published a position paper in which pRDN is only recommended for patients with resistant hypertension [8]. Whether pRDN is a good treatment option, depends partly on the ability to select patients most likely to benefit. True resistant hypertension should be established and white-coat hypertension and other secondary forms of hypertension should be excluded.
This analysis evaluates the results of a standardised stepwise screening of all patients referred to a tertiary centre for treatment with pRDN. The screening consists of a 24-hour ambulatory blood pressure measurement (ABPM), collection of plasma, urine and saliva, and imaging of the renal arteries to assess renal anatomy.

Main results

• The 121 (67%) patients who were excluded from treatment with pRDN, were slightly older, had lower office BP and showed more comorbidity than patients considered eligible.
• 100 (55%) patients continued the standardised stepwise screening protocol after the first screening phase, 14 of whom were diagnosed with secondary hypertension. In 15 antihypertensive treatment was successfully adjusted. Thus, these patients were excluded from further screening. Others were excluded on the basis of severe comorbidities, or limited compliance to prescribed medication and repeatedly not showing up at appointments in the outpatient clinic. 
• All 60 patients who met the inclusion criteria for treatment with pRDN were treated.
• 20 (33%) had additional renal arteries, 17 patients (28%) had additional arteries on one side, and 3 (5%) had dual arteries at both sides.

Conclusion

Only 33% of all referred patients were eligible to undergo pRDN. Patients were excluded when they showed office SBP<160 mmHg, or pseudoresistant hypertension due to a white-coat effect or a secondary cause of hypertension.
The developed screening programme aims to confirm the diagnosis of hypertension. 24-hour ABPM can provide precise information on the status of hypertension, and may prevent further, more expensive screening. Secondary forms of hypertension should be excluded in the screening, as they are unlikely to respond to pRDN. Imaging of the renal arteries is furthermore important to estimate whether pRDN will be beneficial.
This report shows that a substantial proportion of patients suspected to have resistant hypertension, did not have truly resistant hypertension. It would be inappropriate to treat these patients with pRDN. To prevent inappropriate use of pRDN, it is recommended to screen by means of a standardized protocol, preferably in a multidisciplinary setting, with ABPM as a first step.

References

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