|Percutaneous Renal Denervation for the Treatment of Medication-Resistant Hypertension|
Hypertension (defined as systolic BP of >140 mm Hg and a diastolic BP of >90 mm Hg) is an epidemic, affecting nearly 1 billion people worldwide. In the US - it is estimated that more than 56 million adults suffer from high blood pressure, making it more common than cancer, diabetes, and coronary artery disease combined and rivaling obesity in its scope. While many patients are asymptomatic, hypertension exacts a heavy toll on the healthcare system as a major risk factor for heart disease, stroke, and renal disease. And despite the widespread use of antihypertensive meds, only about half of US hypertensive patients are well controlled. In European countries awareness in general population is low and Hypertension prevalence ranges from 37% to 50% of the adult population aged 35-64.
This healthcare epidenic has lead to significant investment in recent years to develop a device-based therapy.
There is now general agreement in the medical community that the condition is multifactorial in nature and hence requires therapeutic approaches targeting several aspects of the underlying pathophysiology. Accordingly, all major guidelines promote a combination of lifestyle interventions and combination pharmacotherapy to reach target blood pressure levels in order to reduce overall cardiovascular risk in affected patients.
Although this approach works for many, it fails in a considerable number of patients for various reasons including drug-intolerance, non-compliance, physician inertia, and others, leaving them at unacceptably high cardiovascular risk. The quest for additional therapeutic approaches to safely and effectively manage hypertension continues.
The kidney plays a vital role in the regulation of blood pressure (sodium filtration, blood volume, etc.) and renal sympathetic nerve hyperactivity (both afferent and efferent) has been demonstrated to be a major factor in the pathophysiology of hypertension. The renal sympathetic efferent nerves innervate the renal tubules, vasculature and juxtaglomerular apparatus and may affect volume and blood homeostasis.
Based on the robust preclinical and clinical data surrounding the role of renal sympathetic nerves in various aspects of blood pressure control, recent efforts have led to the development of novel catheter-based approaches using radiofrequency (RF) energy to selectively target and disrupt the renal sympathetic nerves. Clinical evidence from the treatment of uncontrolled hypertensive patients using RF energy to disrupt the renal sympathetic nerves has shown the therapy has a favorable safety profile and is associated with a substantial and presumably sustained blood pressure reduction.
The available clinical evidence from uncontrolled hypertensive patients in whom percutaneous renal denervation using RF energy has been performed are auspicious and indicate that the procedure has a favorable safety profile and is associated with a substantial and presumably sustained blood pressure reduction (1)
(1) AMERICAN JOURNAL OF HYPERTENSION | VOLUME 24 NUMBER 6 | 635-642 | JUNE 2011