Revelations About Carotid Body Function Through its Pathological Role in Resistant Hypertension

Much recent attention has been given to the carotid body because of its potential role in cardiovascular disease states. One disease, neurogenic hypertension, characterised by excessive sympathetic activity, appears dependent on carotid body activity that may or may not be accompanied by sleep-disordered breathing. Herein, we review recent literature suggesting that the carotid body acquires tonicity in hypertension. We predict that carotid glomectomy will be a powerful way to temper excessive sympathetic discharge in diseases such as hypertension. We propose a model to explain that signalling from the ‘hypertensive’ carotid body is tonic, and hypothesise that there will be a sub-population of glomus cells that channel separately into reflex pathways controlling sympathetic motor outflows

Unilateral Carotid Body Resection in Resistant Hypertension

Animal and human data indicate pathological afferent signaling emanating from the carotid body that drives sympathetically mediated elevations in blood pressure in conditions of hypertension. This first-in-man, proof-of-principle study tested the safety and feasibility of unilateral carotid body resection in 15 patients with drug-resistant hypertension. The procedure proved to be safe and feasible. Overall, no change in blood pressure was found. However, 8 patients showed significant reductions in ambulatory blood pressure coinciding with decreases in sympathetic activity. The carotid body may be a novel target for treating an identifiable subpopulation of humans with hypertension

Preferred Fourth-Line Pharmacotherapy for Resistant Hypertension: Are We There Yet?

© 2017, Springer Science+Business Media New York. Resistant hypertension (RH) is defined as blood pressure (BP) that remains above target levels despite adherence to at least three different antihypertensive medications, typically including a diuretic. Epidemiological studies estimate that RH is increasing in prevalence, and is associated with detrimental health outcomes. The pathophysiology underlying RH is complex, involving multiple, overlapping contributors including activation of the renin-angiotensin aldosterone system and the sympathetic nervous system, volume overload, endothelial dysfunction, behavioural and lifestyle factors. Hypertension guidelines currently recommend specific pharmacotherapy for 1st, 2nd and 3rd-line treatment, however no specific fourth-line pharmacotherapy is provided for those with RH. Rather, five different antihypertensive drug classes are generally suggested as possible alternatives, including: mineralocorticoid receptor antagonists, a1-adrenergic antagonists, a2-adrenergic agonists, ß-blockers, and peripheral vasodilators. Each of these drug classes vary in their efficacy, tolerability and safety profile. This review summarises the available data on each of these drug classes as a potential fourth-line drug and reveals a lack of robust clinical evidence for preferred use of most of these classes in the setting of RH. Moreover, there is a lack of direct comparative trials that could assist in identifying a preferred fourth-line pharmacologic approach and in providing evidence for hypertensive guidelines for adequate treatment of RH