Resistant Hypertension On Treatment (ResHypOT): sequential nephron blockade compared to dual blockade of the renin-angiotensin-aldosterone system plus bisoprolol in the treatment of resistant arterial hypertension - study protocol for a randomized controlled trial

Effect of Sequential Nephron Blockade versus Dual Renin-Angiotensin System Blockade Plus Bisoprolol in the Treatment of Resistant Hypertension, a Randomized Controlled Trial (Resistant Hypertension on Treatment - ResHypOT)

Introduction

Hypertension is the most important modifiable risk factor for cardiovascular disease and a leading public health concern.

Objectives

The primary aim was to compare sequential nephron blockade (SNB) versus dual renin-angiotensin system blockade (DRASB) plus bisoprolol in patients with resistant hypertension to observe reductions in systolic and diastolic blood pressure (SBP and DBP) levels after 20 weeks of treatment.

Material and Methods

This trial was an open-label, prospective, randomized, parallel-group, clinical study with optional drug up-titration. Participants were evaluated during five visits at 28-day intervals.

Results

The mean age was 55.5 years in the SNB and 58.4 years in the DRASB + bisoprolol group (p=NS). Significant office BP reductions were observed in both groups. SNB group, SBP decreased from 174.5±21.0 to 127.0±14.74 mmHg (p<0.0001), and DBP decreased from 105.3±15.5 to 78.11±9.28 mmHg (p<0.0001). DRASB group, SBP decreased from 178.4±21.08 to 134.4 ± 23.25 mmHg (p<0.0001) and DBP decreased from 102.7±11.07 to 77.33±13.75 mmHg (p<0.0001). Ambulatory blood pressure monitoring (ABPM) showed also significant SBP and DBP reductions in both groups (p<0.0001).

Conclusion

In patients with RHTN adherent to treatment, SNB and DRASB plus bisoprolol showed excellent therapeutic efficacy, although SNB was associated with earlier SBP reduction.

Impaired l-arginine-nitric oxide pathway contributes to the pathogenesis of resistant hypertension

The precise mechanisms underlying resistant hypertension remain elusive. Reduced nitric oxide (NO) bioavailability is frequently documented in chronic kidney disease, obesity, diabetes and advanced age, all of which are risk factors for resistant hypertension. Sympathetic overactivity and chronic activation of the renin-angiotensin system are salient features of resistant hypertension. Interestingly, recent data indicate that renal sympathetic overactivity can reduce the expression of neuronal nitric oxide synthase in the paraventricular nucleus. Reduced NO levels in the paraventricular nucleus can increase sympathetic outflow and this can create a vicious cycle contributing to resistant hypertension. Angiotensin II can reduce l-arginine transport and hence NO production. Reduced NO levels may reduce the formation of angiotensin 1-7 dampening the cardio-protective effects of the renin-angiotensin system contributing to resistant hypertension. In addition, interleukin-6 (IL-6) is demonstrated to be independently associated with resistant hypertension, and IL-6 can reduce NO synthesis. Despite this, NO levels have not been quantified in resistant hypertension. Findings from a small proof of concept study indicate that NO donors can reduce blood pressure in patients with resistant hypertension but more studies are required to validate these preliminary findings. In the present paper, we put forward the hypothesis that reduced NO bioavailability contributes substantially to the development of resistant hypertension.

Uncontrolled Arterial Hypertension: Kidney, Neurohormonal Imbalance, and Approaches to Antihypertensive Drug Therapy

Resistant and refractory arterial hypertensions are two distinct clinical phenotypes of uncontrolled arterial hypertension (AH), which differ in their sensitivity to antihypertensive drug therapy. The review presents data obtained in clinical studies devoted to elucidating the involvement of disorders of neurohormonal status and renal function in the formation of resistant and refractory arterial hypertension, to and the development of new approaches to increasing the effectiveness of antihypertensive therapy in these patient’s populations. The results of these studies have shown that in patients with uncontrolled arterial hypertension, despite prolonged intake ≥ 3 antihypertensive drugs with different mechanisms of action, including a diuretic, excess sodium reabsorption persists in the distal segments of nephron due to increased aldosterone activity and sympathetic nervous system hyperactivity. In this regard, special attention has been paid to the data of PATHWAY-2, PATHWAY-3 and ReHOT trials that in patients with resistant AH tested the clinical efficacy of spironolactone, amiloride, and antiadrenergic drugs bisoprolol, doxazosin and clonidine, suppressing activity of the sympathetic nervous system.