Correlation between Renal Artery Anatomy and Hypertension: A Retrospective Analysis of 3000 Patients

Objective. To assess the correlation between renal artery anatomy and blood pressure in Undiagnosed Hypertension and Diagnosed Hypertension. Methods. The renal artery CT scanning imaging data and laboratory data of 3000 inpatients and outpatients were collected retrospectively in 4 centers of China. Morphometric parameters were assessed using the quantitative vascular analysis (unit: mM). Results. 687 cases (23.2%) had accessory renal arteries unilaterally, and 216 cases (7.3%) had bilateral accessory renal arteries, including left kidney 825 (27.9%) and right kidney 798 (27.0%). The presence of accessory renal arteries and renal artery branches was higher in the diagnosed hypertension group as compared with the undiagnosed hypertension group (MARB, p p < 0.001; ARA, p < 0.001; others, p < 0.001). Consequently, multivariate regression analysis showed that age (OR = 2.519 (95% CI: 0.990–6.411, p < 0.001)), dyslipidemia (OR = 1.187 (95% CI: 0.960–1.454, p = 0.007)), renal hilum Outside the main renal artery branch (MRAB) (OR = 2.069 (95% CI: 1.614–2.524, p = 0.002)), and accessory renal artery (ARA) (OR = 2.071 (95% CI: 1.614–2.634, p = 0.001)) were risk factors of hypertension. In addition, higher renin activity was associated with ARA patients (2.19 ± 2.91 vs. 1.75 ± 2.85, p < 0.001). Conclusions. When comparing renal arteries side by side, the anatomical length of the renal arteries is significantly different. In addition, the prevalence of accessory renal arteries and renal artery branches is higher in the hypertension group. The auxiliary renal artery and the main renal artery branch outside the renal portal are independent factors of hypertension. Renal sympathetic nerve activity is affected by renin activity and is related to the accessory renal artery.

Reconstruction of a Lower Polar Artery for Kidney Transplantation Using Donor Ovarian Vein: Case Report with Literature Review

Background: In the case of complicated kidney transplantation, when the accessory artery is severed, the main task is to decide whether to restore renal blood flow and which method should be used. In this report, we present a case of kidney transplantation with vascular reconstruction using an ovarian vein as an interposition graft between a larger branch of the main renal artery and the lower polar artery which was severed during kidney explantation. Case summary: Kidney transplantation using an ovarian vein was performed for a 34-year-old woman with end-stage renal disease on 1 April 2020 in the Hospital of Lithuanian university of health sciences (LUHS) Kaunas Clinics. A lower accessory renal artery was severed during kidney explantation. As the ovarian vein of the donor remained and matched the diameter of the severed vessel, it was decided to use it as an insertion between the main renal artery and the accessory renal artery of the inferior pole. The cold ischemic time was 770 min and the warm ischemic time was 37 min. A month after transplantation, the patient’s condition and daily urine output were normal and the serum creatinine level decreased rapidly. Fifteen months after the surgery, the function and structure of the transplant remained normal and there was no evidence of serious vascular complications on CT scans. This is the first case where graft function was verified after transplantation using three-dimensional CT angiography. Conclusions: If an inferior polar artery is severed, vascular reconstruction must be performed to preserve the function of the graft. Usually, the gonadal vein is available during donor nephrectomy; therefore, it can be explanted without additional difficulties or incisions. Although we have not reported any complications, further studies are recommended on the long-term outcomes of this alternative approach for the reconstruction of short renal arteries.

Beyond Atherosclerosis and Fibromuscular Dysplasia: Rare Causes of Renovascular Hypertension

Renovascular hypertension is one of the most common forms of secondary hypertension. Over 95% of cases of renovascular hypertension are due either to atherosclerosis of the main renal artery trunks or to fibromuscular dysplasia. These two causes of renal artery stenosis have been extensively discussed in recent reviews and consensus. The aim of the current article is to provide comprehensive and up-to-date information on the remaining causes. While these causes are rare or extremely rare, etiologic and differential diagnosis matters both for prognosis and management. Therefore, the clinician cannot ignore them. For didactic reasons, we have grouped these different entities into stenotic lesions (neurofibromatosis type 1 and other rare syndromes, dissection, arteritis, and segmental arterial mediolysis) often associated with aortic coarctation and other arterial abnormalities, and nonstenotic lesions, where hypertension is secondary to compression of adjacent arteries and changes in arterial pulsatility (aneurysm) or to the formation of a shunt, leading to kidney ischemia (arteriovenous fistula). Finally, thrombotic disorders of the renal artery may also be responsible for renovascular hypertension. Although thrombotic/embolic lesions do not represent primary vessel wall disease, they are characterized by frequent macrovascular involvement. In this review, we illustrate the most characteristic aspects of these different entities responsible for renovascular hypertension and discuss their prevalence, pathophysiology, clinical presentation, management, and prognosis.

Endovascular interventions in main renal artery pathologies: an overview and update

Renal arteries are involved in a wide spectrum of pathologies including atherosclerosis, fibromuscular dysplasia, Takayasu arteritis, aneurysms, and aortic type B dissections extending into main renal arteries. They manifest as renovascular hypertension, renal ischemia, and cardiovascular dysfunction. The location of the renal arteries in relation to the abdominal aortic aneurysm is a critical determinant of interventional options and long-term prognosis. This article provides a comprehensive review of the role of interventional radiologists in transcatheter interventions in various pathologies involving the main renal arteries with analysis of epidemiology, pathophysiology, newer interventional techniques, and management options.

Renal Denervation for Uncontrolled and Resistant Hypertension: Systematic Review and Network Meta-Analysis of Randomized Trials

Comparative efficacy and safety of renal denervation (RDN) interventions for uncontrolled (UH) and resistant hypertension (RH) is unknown. We assessed the comparative efficacy and safety of existing RDN interventions for UH and RH. Six search engines were searched up to 1 May 2020. Primary outcomes were mean 24-h ambulatory and office systolic blood pressure (SBP). Secondary outcomes were mean 24-h ambulatory and office diastolic blood pressure (DBP), clinical outcomes, and serious adverse events. Frequentist random-effects network meta-analyses were used to evaluate effects of RDN interventions. Twenty randomized controlled trials (RCTs) (n = 2152) were included, 15 in RH (n = 1544) and five in UH (n = 608). Intervention arms included radiofrequency (RF) in main renal artery (MRA) (n = 10), RF in MRA and branches (n = 4), RF in MRA+ antihypertensive therapy (AHT) (n = 5), ultrasound (US) in MRA (n = 3), sham (n = 8), and AHT (n = 9). RF in MRA and branches ranked as the best treatment to reduce 24-h ambulatory, daytime, and nighttime SBP and DBP versus other interventions (p-scores: 0.83 to 0.97); significant blood pressure effects were found versus sham or AHT. RF in MRA+AHT was the best treatment to reduce office SBP and DBP (p-scores: 0.84 and 0.90, respectively). RF in MRA and branches was the most efficacious versus other interventions to reduce 24-h ambulatory SBP and DBP in UH or RH.

State of Renal Blood Flow in Premature Children with Hemodynamically Significant Patent Ductus Arteriosus

Introduction: Hemodynamically significant patent ductus arteriosus (HSPDA) lowers the renal circulation because of the "ductal stealing phenomenon," which can change the renal blood flow. The aim: To study the state of blood flow in the main renal artery and interlobar renal artery in premature infants with HSPDA. Materials and methods: 74 preterm newborns (gestational age 29-36 weeks) were divided into three groups: І - 40 children with HSPDA, ІІ - 17 children with patent ductus arteriosus (PDA) without hemodynamic disorders, ІІІ - 17 children with closed ductus arteriosus. Color ultrasound Doppler scan of the vascular bed of the kidneys was performed using a microconvex sensor with a frequency of 5-8 MHz ("TOSHIBA" Nemso XG model SSA-580A (Japan) from the main renal artery to the interlobar renal arteries of the right kidney. The following parameters of renal blood flow were studied: peak systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (RI). Results: Peak systolic velocity (PSV) in the main renal artery and interlobar renal arteries did not differ significantly between groups. On the first, third, and tenth days of life, there was a significant decrease in the EDV of blood flow and increased RI in the main renal artery. The EDV of blood flow and RI in the interlobar renal artery on the first day of life did not differ depending on PDA's presence and its hemodynamic significance. On the third and tenth days of life and in the interlobar renal artery, a significant decrease in EDV of blood flow and increased RI were noted. These renal blood flow characteristics were closely related to the size of the PDA on the first day of life. Conclusion: A feature of renal hemodynamics in HSPDA in premature infants is a decrease in the EDV of blood flow in the main renal artery and interlobar renal artery, as well as an increase in the RI of these vessels, directly correlating with the size of the PDA in the first day of life. During the first ten days of life, dynamic control revealed a slowed process of restoration of renal blood flow in babies with HSPDA, despite the PDA's closure.

Acute renal artery thrombosis associated with the use of an oral contraceptive pill

Peripheral, and even visceral, venous thromboembolism is a known complication of oral contraceptive drugs (OCPs) but arterial disease, leading to renal infarction, is rarely reported. We describe a 36-year-old female patient who presented with sudden left loin pain for 2 days. Ultrasound examination showed a wedge-shaped echogenic lesion at lateral side of the left kidney. Computed tomography with contrast showed the area to be avascular and the arteriogram showed abrupt loss of the dorsal branch of left main renal artery, which lacked any deformities, confirming diagnosis of thrombosis-in-situe. Moreover, the pelvicalyceal system did not show abnormality which ruled out ascending infection. The patient did not have a family history or laboratory evidence of hypercoagulable disorder. An OCP was the only medication she had received in the previous 3 months. The OCP was discontinued, and the patient was treated with heparin for 3 days then Abixaban for 6 months. Subsequent CT study with contrast, 3 months later, showed lateral kidney scar. On follow up; she did not have subsequent thrombotic events up to 1 year. Keywords: Abixaban, infarction, Kidney, oral contraceptive, thrombosis.

Main Renal Artery Plus Branch Ablation in the Treatment of Resistant Hypertension with Renal Denervation

Objective: To study the safety and efficacy of denervation of renal artery branches in the treatment of resistant hypertension.Methods: Sixty patients with resistant hypertension were enrolled. The patients were randomly assigned to the mainrenal artery plus branch ablation group or the main renal artery ablation group. The clinical data and operation-relatedparameters, including number of ablation points, temperature, and average energy, were recorded. Ambulatory bloodpressure were taken for all patients at the baseline and at 6 months after treatment. Office blood pressure was recordedbefore treatment and after treatment every 3 months for 2 years.Results: Sixty patients with resistant hypertension were enrolled in this study. There were 30 patients in each group.Angiography was performed after ablation. No renal artery complications, such as stenosis and dissection, occurredin the two groups. There was no significant difference in age, sex, BMI, comorbid disease, and medication betweenthe two groups (P > 0.05). The number of ablation points for the main renal artery plus branch ablation group wasgreater than that for the main renal artery ablation group. The office blood pressure and 24-hour blood pressure weresignificantly lower 6 months after treatment than before treatment in both groups (P < 0.05). Office blood pressure inthe main renal artery plus branch ablation group was lower than that in the main renal artery ablation group during the3–12-month follow-up period, with a statistical difference. However, as the follow-up time increased, the differencedisappeared.Conclusion: The results of this study show that main renal artery plus branch ablation is a safe interventional method,but there was no obvious advantage on long-term follow-up compared with only main renal artery ablation.

Comparative analysis of cardioprotective effects of two renal denervation techniques

Aim. To compare cardioprotective effects of two renal denervation (RD) techniques: main renal artery or its branches after bifurcation in patients with resistant hypertension (RH).Materials and methods. This randomized double-blind clinical (ClinicalTrials. gov. identifier: NCT02667912) study with a follow-up of 12,3±1,6 months included 55 patients with RH, which was divided into 2 groups: group 1 (n=27) — main renal artery denervation; group 2 — RD of branches. Mean age of patients was 57,3±9,5 and 56,4±9,3 years, respectively. We assessed structural and functional cardiac characteristics using two-dimensional speckle-tracking echocardiography (STE).Results. Initially, the patients in the groups did not differ in terms of studied parameters and therapy. After RD in both groups, the levels of myocardial stress significantly decreased; 95% confidence interval: after main renal artery denervation — systolic [-4802; -2896], diastolic [-3264; -2032] dyne/cm2; after RD of branches — [-6324; -5328] and [-4021; -2521] dyne/cm2, respectively (p=0,001 and 0,024, respectively). After main renal artery denervation, there was a decrease in the left ventricular (LV) wall thickness (interventricular septum [1,06; -0,62] and posterior wall [0,12; -0,62]) in comparison with RD of branches ([-0,68; -1,28] and [-0,68; -1,06], respectively). These differences were significant: p=0,023 and 0,021, respectively. After distal RD, decrease in the LV mass was observed more often by 21,2%, an increase in the LV mass was 2 times less frequent. Restoration of diastolic function was more common in patients after distal RD than main renal artery denervation (26% vs 13%, respectively). According to pilot analysis, STE parameters was also improved.Conclusion. Twelve months after distal RD, compared with the main renal artery denervation, the LV wall thickness, number of patients with LV hypertro -phy, and diastolic dysfunction decreased significantly greater. Two-dimensional STE revealed improvement of cardiac parameters. The results require further research.