Renal Denervation Therapy for Hypertension

Abstract

An overweight 78-year-old man with hypertension treated with spironolactone (50 mg daily), amlodipine (10 mg daily), lisinopril (40 mg daily), and extended-release metoprolol (200 mg daily), intolerant of multiple antihypertensives including clonidine (dry mouth) and hydralazine (diarrhea), is referred for renal sympathetic denervation (RSDN). He reports dietary and medication compliance. Secondary causes of hypertension have been excluded. Blood pressure (BP) is 184/93 mm Hg. Hypertension remains a major modifiable risk factor associated with cardiovascular morbidity and mortality.1 Resistant hypertension is defined as BP≥160/100 mm Hg, despite maximally tolerated doses of ≥3 classes of antihypertensives, including a diuretic, without secondary hypertension (eg, renovascular hypertension, chronic kidney disease, mineralocorticoid excess, or obstructive sleep apnea).2 Recently, the prevalence of resistant hypertension in patients with atherosclerosis was reported to be 12.7%.3 It is associated with a high risk for future adverse cardiovascular events.4 Sympathetic hyperactivity promotes hypertension (Figure 1). In hypertensive rats demonstrating renal sympathetic hyperactivity, renal efferent denervation delays the onset and lessens the severity of hypertension.5 Renal afferent denervation through dorsal rhizotomy mitigates hypertension.6 Following renal transplantation, sympathetic hyperactivity continues until the diseased kidneys are excised; BP improvement typically follows.7 The BP reduction following renal excision provides evidence that detrimental sympathetic signals originate from diseased kidneys.8 Figure 1. Systemic effects of sympathetic nervous system hyperactivity. Before modern pharmacotherapy, malignant hypertension had a ≈100% mortality at 5 years.9 Radical sympathectomy was used and RSDN was achieved, albeit nonselectively. In an observational study of 1266 patients undergoing sympathectomy in comparison with 467 treated conventionally, improved survival rates and BP control were demonstrated with surgery. …