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

Refractory Arterial Hypertension: Features of Neurohormonal and Water-salt Imbalanceand Approaches to Antihypertensive Drug Therapy

Refractory arterial hypertension is characterized by a lack of control of target blood pressure, despite the prolonged use >5 antihypertensive drugs with different mechanisms of action, including longacting diuretic chlorthalidone and the mineralcorticoid receptor antagonists (spironolactone or eplerenone). The review presents the results of clinical studies devoted the elucidating peculiarities of the neurohormonal status and water-salt balance in such patients and developing new approaches to antihypertensive drug therapy based on them. According to these studies, individuals with refractory hypertension differ from patients with resistant hypertension with the higher of sympathetic nervous system activity and the absence of an increased of intrathoracic fluid volume, which indirectly indicates a significant decrease in the intravascular fluid volume. In this regard, the review focuses on the data obtained in assessing the clinical efficacy of sympatholytics clonidine and reserpine in patients with resistant and refractory hypertension, as well as renal sodium-glucose co-transporter type 2 inhibitors, which suppress the sympathetic nervous system activity and can be used to overcome refractory hypertension in patients with type 2 diabetes.

Refractory and Resistant Hypertension in Patients with Type 2 Diabetes Mellitus: Different Response to Renal Denervation

Aim      To compare the antihypertensive effectivity of renal denervation in patients with diabetes mellitus (DM) and associated refractory arterial hypertension (rfAH) (treated with 5 or more classes of antihypertensive drugs, including a thiazide diuretic and a mineralocorticoid receptor antagonist) and uncontrolled resistant AH (ucAH) (treated with 3-4 drugs).Material and methods  This interventional study with renal denervation included 18 DM patients with rfAH and 40 DM patients with ucAH; 16 and 36 of them, respectively, completed the study in 6 months. At baseline, patients were sex- and age-matched. Study methods included measurement of office blood pressure (BP; systolic/diastolic BP, SBP/DBP); outpatient BP monitoring; evaluation of kidney function (estimated glomerular filtration rate by the CKD-EPI formula); diurnal diuresis volume; diurnal urinary excretion of albumin, potassium and sodium; diurnal excretion of metanephrines and normetanephrines; and plasma levels of glucose and glycated hemoglobin, aldosterone, and active renin. Patients were instructed about maintaining compliance with their antihypertensive and hypoglycemic therapy throughout the study.Results At baseline, patients of both groups were comparable by BP and major clinical indexes, except for higher values of nocturnal SBP variability (p<0.05) in patients with rfAH. At 6 months following renal denervation, both groups displayed significant decreases in office and average daily SBP and also in the "load" with increased mean diurnal SBP. However, the decrease in average daily SBP was almost 4 times greater in the rfAH group than in the ucAH group ( -19.9 and -5.1 mm Hg, respectively, р=0.02). Moreover, 81 % of patients in the rfAH group responded to the intervention (average daily SBP decrease ≥10 mm Hg) while the number of responders in the ucAH group was considerably smaller (42 %; p=0.02). In patients with rfAH, renal denervation was associated with a significant decrease in pulse BP and nocturnal SBP variability and with the increase in diurnal diuresis. No other alterations were noted in laboratory test results in either group.Conclusion      DM patients with rfAH may be the best candidates for the procedure of renal denervation.

[Refractory and resistant hypertension in patients with type 2 diabetes mellitus: differences in metabolic profile and endothelial function]

AIM

To determine the prevalence of refractory hypertension (RfH) in patients with and without type 2 diabetes mellitus (DM), as well as to evaluate whether diabetic patients with RfH significant differ from those with uncontrolled resistant hypertension (RH) in clinical phenotype, metabolic profile and endothelial function.

MATERIALS AND METHODS

The study included 193 patients with RH: RH 74 patients with diabetes and 119 patients without DM. Uncontrolled RH and RfH were defined by the presence of uncontrolled blood pressure BP (140 and/or 90 mm Hg) despite the use of 3 but 5 antihypertensive drugs (for RH) and 5 antihypertensive drugs, including a mineralocorticoid receptor antagonist (for RfH). Clinical examination, lab tests were performed. Flow-mediated dilation (FMD) and vasoreactivity of middle cerebral artery (MCA) using both breath-holding and hyperventilation test were measured by high-resolution ultrasound.

RESULTS

The prevalence of refractory hypertension in patients with and without DM was similar (30% vs 28%, respectively). No differences in BP levels, data of echocardiography and clinical phenotype were found between the diabetic groups, but value of HOMA index, plasma resistin level and postprandial glycaemia were higher in patients with RfH. FMD and MCA reactivity to the breath-holding test were worse in patients with RfH, and they had a more pronounced vasoconstrictor response of MCA to the hyperventilation test compared to patients with RH.

CONCLUSION

The prevalence of RfH is the same in patients with and without diabetes. Diabetic patients with refractory hypertension have a more unfavorable metabolic profile and greater impairment of endothelial function than patients with uncontrolled resistant hypertension.