Renovascular Hypertension: Novel Insights

Pathophysiology of spontaneous coronary artery dissection: hematoma, not thrombus

Spontaneous coronary artery dissection (SCAD) accounts for 1.7%-4% of all acute coronary syndrome presentations, particularly among young women with an emerging awareness of its importance. The demarcation of acute SCAD from coronary atherothrombosis and the proper therapeutic approach still represents a major clinical challenge. Certain arteriopathies and triggers are related to SCAD, with high variability in their prevalence, and often, the cause remains unknown. The objective of this review is to provide contemporary knowledge of the pathophysiology of SCAD and possible therapeutic solutions.

Research progress of moyamoya disease combined with renovascular hypertension

Moyamoya disease (MMD) is an idiopathic cerebrovascular disease which was first described by Suzuki and Takaku in 1969. Moyamoya disease is a non-atherosclerotic cerebrovascular structural disorder. MMD has been found all over the world, especially in Japan, Korea, and China. In recent years, many reports pointed out that the changes of vascular stenosis in patients with moyamoya disease occurred not only in intracranial vessels, but also in extracranial vessels, especially the changes of renal artery. Renovascular hypertension (RVH) is considered to be one of the important causes of hypertension in patients with moyamoya disease. The pathogenesis of moyamoya disease combined with renovascular hypertension is still unclear, and the selection of treatment has not yet reached a consensus. This article reviews the latest research progress in epidemiology, RNF213 gene, pathomorphology, clinical characteristics and treatment of moyamoya disease combined with renovascular hypertension, in order to provide reference for clinical workers.

The role of nitric oxide in renovascular hypertension: from the pathophysiology to the treatment

Renovascular hypertension is one of the most relevant causes of secondary hypertension, mostly caused by atherosclerotic renovascular stenosis or fibromuscular dysplasia. The increase in angiotensin II production, oxidative stress, and formation of peroxynitrite promotes the decrease in nitric oxide (NO) availability and the development of hypertension, renal and endothelial dysfunction, and cardiac and vascular remodeling. The NO produced by nitric oxide synthases (NOS) acts as a vasodilator; however, endothelial NOS uncoupling (eNOS) also contributes to NO reduced availability in renovascular hypertension. NO donors and NO-derived metabolites have been investigated in experimental renovascular hypertension and have shown promissory effects in attenuating blood pressure and organ damage in this condition. Therefore, understanding the role of decreased NO in the pathophysiology of renovascular hypertension promotes the study and development of NO donors and molecules that can be converted into NO (such as nitrate and nitrite), contributing for the treatment of this condition in the future.

Retrograde Recanalization for Proximal Occlusion of the Right Renal Artery through a Compensated Collateral Artery in a 10-year-old Patient

BACKGROUND

To describe a retrograde recanalization for the proximal occluded lesion in right renal artery (RRA) in young patient with fibromuscular dysplasia (FMD).

METHODS

A 10-year-old girl presented to our hospital with proximal RRA occlusion and refractory hypertension though she took anti-hypertension medicines. Her renin and aldosterone were beyond the normal level in both base state and excited state. Her glomerular filtration rate at right kidney was only 18.4 ml/min. Angiography revealed proximal RRA occlusion and a compensated collateral artery (CCA) from the infrarenal aorta to the RRA. She was thus diagnosed with focal FMD. A retrograde recanalization was performed through this CCA.

RESULTS

Angioplasty and stenting were successfully performed to treat the proximal RRA occlusion. Postoperatively, the glomerular filtration rate in the right kidney improved. One-year follow-up revealed that, the blood pressure maintained at normal range without any antihypertensive agents. No other discomfort was complained.

CONCLUSIONS

It is feasible to establish a working pathway with patient's compensated collateral artery to treat the renal artery occlusion.

Açaí Reverses Adverse Cardiovascular Remodeling in Renovascular Hypertension: A Comparative Effect With Enalapril

ABSTRACT

This study aimed to determine if açai seed extract (ASE) could reverse pre-existing cardiovascular and renal injury in an experimental model of renovascular hypertension (2 kidney, 1 clip, 2K1C). Young male rats (Wistar) were used to obtain 2K1C and sham groups. Animals received the vehicle, ASE (200 mg/kg/d), or enalapril (30 mg/kg/d) in drinking water from the third to sixth week after surgery. We evaluated systolic blood pressure by tail plethysmography, vascular reactivity in the rat isolated mesenteric arterial bed (MAB), serum and urinary parameters, plasma inflammatory cytokines by ELISA, MAB expression of endothelial nitric oxide synthase and its active form peNOS by Western blot, plasma and MAB oxidative damage and antioxidant activity by spectrophotometry, and vascular and cardiac structural changes by histological analysis. ASE and enalapril reduced the systolic blood pressure, restored the endothelial and renal functions, and decreased the inflammatory cytokines and the oxidative stress in 2K1C rats. Furthermore, both treatments reduced vascular and cardiac remodeling. ASE substantially reduced cardiovascular remodeling and recovered endothelial dysfunction in 2K1C rats probably through its antihypertensive, antioxidant, and anti-inflammatory actions, supplying a natural resource for the treatment of renovascular hypertension.

[Clinical ultrasound in nephrology]

When used correctly, modern ultrasound diagnostics are helpful for the nephrologist especially in emergency situations on the ward, in dialysis and in the emergency admission to quickly make the correct diagnosis or as a diagnostic gatekeeper to initiate the correct next diagnostic and therapeutic steps in a time-saving manner. In addition to conventional B‑mode/gray scale sonography and Doppler sonography, new ultrasound transducers with higher spatial resolution and above all contrast agent sonography have significantly expanded the technical possibilities and help nephrologists and internists to answer diagnostic and clinical questions. This particularly applies to the kidneys, which up to now could only be clarified by means of contrast-enhanced computed tomography or magnetic resonance imaging. This will allow the nephrologist in 2021 to amalgamate the clinical symptoms, imaging results and pathophysiological knowledge in an ideal, time-saving manner for the benefit of the patient.

Left ventricular mass reduction and hypertrophy regression following renal artery revascularization: a meta-analysis

AIM

Few echocardiographic studies have focused on regression of left ventricular hypertrophy (LVH) in patients with renal artery stenosis after revascularization, with inconsistent results. We performed a systematic meta-analysis of these studies in order to offer a comprehensive information on this topic.

METHODS

The PubMed, OVID-MEDLINE, and Cochrane library databases were analyzed to search English-language articles published from 1 January 1990 up to 31 March 2020. Studies were identified by crossing the following terms: 'renal artery stenosis', 'renovascular hypertension', 'fibromuscular dysplasia', 'renal artery stenting', 'renal artery surgery' with 'cardiac damage', 'hypertensive heart disease' 'left ventricular mass', 'left ventricular hypertrophy', 'echocardiography'.

RESULTS

A total of 726 hypertensive patients with renal artery stenosis (mean age 61 years, 64% men, 98% treated, 10% with fibromuscular dysplasia) were included in 13 studies. Baseline and postintervention pooled mean LVM values were 220 ± 15 and 203 ± 19 g, respectively (SMD -0.24 ± 0.06, CI -0.37 to -0.21, P<0.0001); corresponding values for LV mass index were 129.0 ± 6 and 115 ± 7 g/m, respectively (SMD -0.28 ± 0.04, CI -0.36 to 0.21, P < 0.0001). Renal revascularization was associated with a 40% lower risk of LVH. This trend was accompanied by a reduction in the number of antihypertensive drugs (SMD -0.27 ± 0.04, CI -0.37 to 0.17, P < 0.0001).

CONCLUSION

The present meta-analysis suggests that renal artery revascularization added to antihypertensive therapy promotes a favourable effect on LV structure, as reflected by a significant decrease in absolute and indexed LV mass index as well by a lower risk of LVH. Limitations include: high prevalence of modest renal artery stenosis (≥50%); small sample of fibromuscular dysplasia; lack of randomized design of most studies.

Secondary Hypertension: Novel Insights

It is estimated that 5-10% of hypertensive patients have secondary hypertension. The main causes of secondary hypertension are parenchymal renal disease, primary aldosteronism and renovascular hypertension. The identification of these patients is important because it enables the etiological management of the underlying disease and in some cases leads to blood pressure control without antihypertensive medications. On the other hand, diagnostic evaluation for secondary hypertension often includes complex and expensive tests and should be performed only in patients with a strong clinical suspicion for its presence. If preliminary screening tests suggest the presence of secondary hypertension, these patients should be referred to specialized centers for further diagnostic evaluation and comprehensive management.