Methods Study Design and Patients

Approximately 10 % of patients treated for hypertension remain with uncontrolled high blood pressure (BP), despite prescription of antihypertensive drugs.1 Renal sympa-thetic denervation has been introduced as a new treatment of hypertension apparently resistant to drug treatment.2 However, it has been known for decades that poor drug adherence is a major problem among these patients.3,4 It is unknown to what degree the decline in BP after renal denervation (RDN)2 is caused by denervation itself or concomitantly improved drug adherence. We aimed to investigate for the first time the BP lowering effect of RDN in treatment-resistant hypertension after witnessed intake of medication just before qualifying ambulatory BP