A possible explanation for the frequent concomitance of arterial hypertension and multiple renal arteries

The prevalence of accessory renal arteries in sudanese population in Khartoum State: a cross-sectional CT study from 2017 to 2020

BACKGROUND

Renal artery variations are clinically significant due to their implications for surgical procedures and renal function. However, data on these variations in Sudanese populations are limited. This study aimed to determine the prevalence and characteristics of renal artery variations in a Sudanese population.

METHODS

A cross-sectional retrospective study was conducted in Khartoum state from October 2017 to October 2020. A total of 400 Sudanese participants who underwent abdominal CT scans were included. Data on demographic characteristics, kidney measurements, and renal vasculature were collected and analyzed using descriptive statistics and inferential tests.

RESULTS

The mean age of participants was 46.7 ± 18 years, with a nearly equal gender distribution. Overall, renal artery variations were present in 11% of participants, with accessory renal arteries observed in 6% of the study population. Among those with accessory vessels, 50% were on the right side, 29.2% on the left, and 20.8% bilateral, distributed across hilar 29.2%, lower polar 29.2%, and upper polar 41.7% regions. No significant associations were found between accessory renal arteries and age or gender (p-value > 0.05). However, participants with accessory renal arteries exhibited significantly narrower width 5.0 ± 1.4 than those with no with accessory renal arteries 5.8 ± 1.1 (p-value 0.002) Early dividing renal arteries were found in 5% of participants, with nearly half being bilateral. No significant associations were found between the presence of early dividing renal arteries and demographic or renal measurements (p-value > 0.05).

CONCLUSION

This study provides valuable insights into the prevalence and characteristics of renal artery variations in a Sudanese population. The findings contribute to our understanding of renal anatomy in this demographic and can inform clinical practice and surgical planning, particularly in renal transplantation and other renal procedures.

Effect of Accessory Renal Arteries on Essential Hypertension and Related Mechanisms

BACKGROUND

This case-control study aimed to determine whether there were differences between patients with essential hypertension with accessory renal arteries (ARAs) and those without ARAs.

METHODS AND RESULTS

The enrolled patients with essential hypertension were divided into the ARA group (n=200) and control group without ARAs (n=238). After propensity matching, 394 patients (197 in each of the 2 groups), were included. The 24-hour BP (4.33/2.43 mm Hg) and daytime BP (4.48/2.61 mm Hg) of patients in the ARA group were significantly higher than those of the control group (P<0.05). The flow-mediated dilation was lower in the ARA group (5.98±2.70 versus 5.18±2.66; P<0.05). In correlation analysis, the horizontal plasma aldosterone concentration had the highest correlation with 24-hour, daytime, and nighttime systolic BP (r=0.263, 0.247, and 0.243, respectively; P<0.05) and diastolic BP (r=0.325, 0.298, and 0.317, respectively; P<0.05). As for multivariate regression analysis, plasma aldosterone concentration was a significant risk factor for elevated 24-hour, daytime, and nighttime systolic BP (β=0.249 [95% CI, 0.150-0.349], 0.228 [95% CI, 0.128-0.329], and 0.282 [95% CI, 0.187-0.377], respectively; P<0.05) and elevated diastolic BP (β=0.289 [95% CI, 0.192-0.385], 0.256 [95% CI, 0.158-0.353], and 0.335 [95% CI, 0.243-0.427], respectively; P<0.05). Direct renin concentration was also a risk factor for 24-hour and daytime BPs, whereas heart rate was a risk factor correlated with 24-hour, daytime, and nighttime diastolic BP (all P<0.05). For the mixed-effects model for repeated measures, the results were similar to results of the multivariate regression analysis (all P<0.05).

CONCLUSIONS

ARAs could contribute a higher BP of patients with essential hypertension and might promote the development of essential hypertension. The mechanism might be related to overactivation of the renin-angiotensin-aldosterone system and sympathetic nervous system.

Anatomic Variations of Renal Arteries as an Important Factor in the Effectiveness of Renal Denervation in Resistant Hypertension

Hypertension remains the leading cause of death worldwide. Despite advances in drug-based treatment, many patients do not achieve target blood pressure. In recent years, there has been an increased interest in invasive hypertension treatment methods. Long-term effects and factors affecting renal denervation effectiveness are still under investigation. Some investigators found that the renal arteries' morphology is crucial in renal denervation effectiveness. Accessory renal arteries occur in 20-30% of the population and even more frequently in patients with resistant hypertension. Diversity in renal vascularization and innervation may complicate the renal denervation procedure and increase the number of people who will not benefit from treatment. Based on previous studies, it has been shown that the presence of accessory renal arteries, and in particular, the lack of their complete denervation, reduces the procedure's effectiveness. The following review presents the anatomical assessment of the renal arteries, emphasizing the importance of imaging tests. Examples of imaging and denervation methods to optimize the procedure are presented. The development of new-generation catheters and the advancement in knowledge of renal arteries anatomy may improve the effectiveness of treatment and reduce the number of patients who do not respond to treatment.

Artificial Urinary Sphincter With Bilateral Atrophic Kidneys and Accessory Renal Arteries in a Male Cadaveric Subject: A Case Report and Clinicopathological Reconciliation of Urinary Abnormalities and Embryogenetic Correlation of Vascular Aberrations

A unique combination of triple abnormality in a willed male body donor dissection, with putative clinicopathological correlations during the subject's lifetime, is described in this case report. The subject had a three-piece artificial urinary sphincter surgically implanted around the proximal corpus spongiosum, left scrotal pouch and in the lower left abdominal wall, ostensibly for urinary incontinence during his lifetime, though the etiology of the latter was not immediately obvious. He also had a total of three accessory renal arteries involving both sides, complicated by bilateral diffuse renal atrophy from presumable glomerulosclerosis or nephrosclerosis-induced nephrotic syndrome. While each entity may not be so unique per se, each is not too common either. The combination of all three findings has not been described to date in the contemporary literature in a single male cadaver dissection. Only seven reports of artificial urinary sphincter studies on human cadaver subjects could be detected in contemporary literature, this being the eighth. Finally, there were no apparent etiopathological or pathogenetic mechanisms to explain the occurrence of each or the coexistence of all of them in a single male cadaveric subject. The artificial urinary sphincter was reviewed with respect to its characteristics, placement, and efficacy. An attempt was made to establish the cause-effect relationship between the artificial sphincter and urinary incontinence that necessitated the implant. Thereafter, a clinicopathological correlation was proposed in this case report to reconcile the concomitance of urinary incontinence, bilateral accessory renal arteries, and bilateral renal atrophy. An embryogenetic mechanism of the aberrant renal arteries was also suggested. Physician awareness from the standpoint of preoperative investigation of such cases was also highlighted.

Relationship between accessory renal arteries and resistant hypertension: A cohort study

BACKGROUND

Resistant hypertension (RHT) is a major health care concern affecting 20 to 30% of hypertensive patients and increasing cardiovascular risk. Recent renal denervation trials have suggested a high prevalence of accessory renal arteries (ARA) in RHT. Our objective was to compare the prevalence of ARA in RHT vs. non-resistant hypertension (NRHT).

METHODS

Eighty-six patients with essential hypertension who benefited from an abdominal CT-scan or MRI during their initial workup were retrospectively recruited in 6 French ESH (European Society of Hypertension) centers. At the end of a follow-up period of at least 6 months, patients were classified between RHT or NRHT. RHT was defined as uncontrolled blood pressure despite the optimal doses of three antihypertensive agents of which one is a diuretic or similar, or controlled by ≥ 4 medications. Blinded independent central review of all radiologic renal artery charts was performed.

RESULTS

Baseline characteristics were: age 50±15 years, 62% males, BP 145±22/87±13mmHg. Fifty-three (62%) patients had RHT and 25 (29%) had at least one ARA. Prevalence of ARA was comparable between RHT (25%) and NRHT patients (33%, P=0.62), but there were more ARA per patient in NRHT (2±0.9) vs. RHT (1.3±0.5, P=0.05), and renin levels were higher in ARA group (51.6±41.7 mUI/L vs. 20.4±25.4 mUI/L, P=0.001). ARA were similar in diameter or length between the 2 groups.

CONCLUSIONS

In this retrospective series of 86 essential hypertension patients, we found no difference in the prevalence of ARA in RHT and NRHT. More comprehensive studies are needed to answer this question.

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, pp < 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.

Hypertension and renal outcomes in normotensive kidney donors with multiple renal arteries

Having multiple renal arteries (MRA) has been linked to hypertension development. Whether kidney donors who are left with MRA in the nondonated kidney incur a higher risk of hypertension has not been studied. We compared the development of hypertension, reduced estimated glomerular filtration rate (eGFR), cardiovascular disease, and mortality in 2624 normotensive kidney donors with MRA in the nondonated kidney and to 2624 propensity score matched normotensive donor controls with a single renal artery. In total, 35% of donors had MRA. Donors with MRA were less likely to have undergone a left nephrectomy (51% vs. 83%). Postdonation hypertension was associated with age, male gender, non-White ethnicity, obesity, and family history of hypertension. Having MRA was not associated with risk of hypertension; aHR 0.92 (95% CI 0.82-1.03), P = 0.16. After 17 ± 11 years from donation, a similar proportion of donors with and without MRA developed cardiovascular disease, proteinuria and eGFR <30, <45 and <60 mL/min/1.73 m² and the multivariable risks of developing these outcomes were similar in the two groups. Our study did not show increased risk for hypertension, reduced eGFR, proteinuria or cardiovascular disease in donors with MRA in the remaining kidney and without hypertension at donation.

Renal Volumetry-based Prediction of the Presence of Accessory Renal Artery: Computed Tomographic Angiography-based Study with Clinical Implications on Renal Doppler

Background

The objective was to validate the hypothesis and evaluate whether the presence or absence of accessory renal artery can be predicted on the basis of volumetric parameters of kidney and diameter of the main renal artery (mRA).

Methods

This retrospective analysis was performed in a total of 60 kidneys in 30 patients, who had computed tomographic (CT) angiography. The kidneys were segregated into control and study groups depending on the absence or presence of accessory renal artery. The total renal volumes were measured using renal length, breadth, and height in mm³. The renal artery diameters were also measured in mm, in the postostial segment. Renal volume/renal artery diameter (V/d) was measured for each kidney in two groups, and the difference in mean V/d values (in mm²) in two groups was measured for statistical significance.

Results

The mean V/d value in the study group with presence of the accessory renal artery was found to be 23,444.7 mm² (range: 16,229.1-32,490.0). The V/d value in the control group with the absence of accessory renal artery was found to be 19,717.15 mm² (range: 13,704.6-28,000.0). The mean values in the two groups showed a statistically significant difference in the V/d with a P value of 0.001 (P < 0.05).

Conclusion

The study suggests that the possibility of the presence of the accessory renal artery is directly proportional to the total renal volume and inversely proportional to the diameter of mRA. The use of integrated volumetric parameter (V/d) is therefore likely to play a key role in the prediction of the presence of accessory renal artery on imaging studies. Renal volumetry on CT angiography may help predict the presence of accessory renal artery and thus may have implications on renal Doppler studies.

Renin dependent hypertension caused by accessory renal arteries

Background

Hypokalemia in the presence of hypertension is often attributed to primary hyperaldosteronism as a cause of secondary hypertension, however secondary hyperaldosteronism may present similarly. Accessory renal arteries are variants in the vascular anatomy which are often thought to be innocuous but in some circumstances can cause renovascular hypertension leading to secondary hyperaldosteronism.

Case presentation

We report 2 cases of hypertension with secondary hyperaldosteronism associated with accessory renal arteries. Both patients presented with hypokalemia and further investigations revealed hyperaldosteronism with unsuppressed renin levels. Imaging studies showed the presence of accessory renal artery.

Conclusion

Accessory renal arteries are a potential cause renovascular hypertension which can be detected via CT angiography or magnetic resonance angiography. Hormonal evaluation should be undertaken to determine whether its presence contributes to hypertension in the patient as targeted treatment such as aldosterone antagonist can be initiated. Surgical intervention or renal denervation may be considered in resistant cases.

Accessory renal arteries: Prevalence in resistant hypertension and an important role in nonresponse to radiofrequency renal denervation

OBJECTIVE

The aim of this study was to understand the role of accessory renal arteries in resistant hypertension, and to establish their role in nonresponse to radiofrequency renal denervation (RDN) procedures.

BACKGROUND

Prior studies suggest a role for accessory renal arteries in hypertensive syndromes, and recent clinical trials of renal denervation report that these anomalies are highly prevalent in resistant hypertension. This study evaluated the relationships among resistant hypertension, accessory renal arteries, and the response to radiofrequency (RF) renal denervation.

METHODS

Computed Tomography Angiography (CTA) and magnetic resonance imaging (MRI) scans from 58 patients with resistant hypertension undergoing RF renal denervation (RDN) were evaluated. Results were compared with CT scans in 57 healthy, normotensive subjects undergoing screening as possible renal transplant donors. All scans were carefully studied for accessory renal arteries, and were correlated with long term blood pressure reduction.

RESULTS

Accessory renal arteries were markedly more prevalent in the hypertensive patients than normotensive renal donors (59% vs 32% respectively, p=0.004). RDN had an overall nonresponse rate of 29% (response rate 71%). Patients without accessory vessels had a borderline higher response rate to RDN than those with at least one accessory vessel (83% vs 62% respectively, p=0.076) and a higher RDN response than patients with untreated accessory arteries (83% vs 55%; p=0.040). For accessory renal arteries and nonresponse, the sensitivity was 76%, specificity 49%, with positive and negative predictive values 38% and 83% respectively.

CONCLUSIONS

Accessory renal arteries were markedly over-represented in resistant hypertensives compared with healthy controls. While not all patients with accessory arteries were nonresponders, nonresponse was related to both the presence and non-treatment of accessory arteries. Addressing accessory renal arteries in future clinical trials may improve RDN therapeutic efficacy.

Renal denervation in a patient with unilateral ectopic kidney in the pelvis and refractory hypertension

Ectopic kidney and inherent vascular abnormalities may result in renovascular hypertension. The case we report is peculiar as a left ectopic iliac kidney supplied by a superior and an inferior polar renal arteries was detected in a treatment-resistant hypertensive man. In conclusion, percutaneous renal artery denervation was successfully performed in the right renal artery and in both left accessory renal arteries, obtaining excellent blood pressure decrease at follow-up.

Kidney Transplant with Multiple Renal Artery Grafts from Deceased Donors: Are Long-Term Graft and Patient Survival Compromised?

Background—

Kidneys with multiple arteries are often transplanted. However, the long-term outcome of such kidneys recovered exclusively from deceased donors is not clear.

Objective—

To determine whether use of renal grafts with multiple arteries affects long-term graft survival and function.

Methods—

The outcomes of 259 consecutive kidney transplants between 1996 and 2000 were retrospectively reviewed. Patients were divided into 2 groups, multiple renal artery graft recipients (n = 70) and single renal artery graft recipients (n = 189). Short-term complications and long-term outcomes (survival rates, blood pressure after transplant, creatinine clearance, and proteinuria levels at 1, 3, 5, and 7 years after transplant) were compared between the 2 groups.

Results—

Early vascular complications were more common ( P = .02) in multiple artery graft recipients (18.6%) than in single artery graft recipients (7.9%), mainly because of occlusion of a polar artery in grafts with multiple renal arteries (7.1%). Urologic complications were no more frequent in one group than in the other (5.7% vs 5.3%; P = .89). The 2 groups did not differ significantly ( P = .33) in long-term graft survival, with a median follow-up of 9.05 years (range, 0.1–12.7 years). Mean (SD) for creatinine clearance (59.4 [22.6] vs 55.9 [20.3] mL/min; P = .47), proteinuria (0.77 [2.1] vs 0.4 [0.8] g/24 h; P = .19), and systolic blood pressure (133.6 [14.5] vs 133.7 [17.5] mm Hg; P = .85) did not differ significantly between the 2 groups 7 years after transplant.

Conclusions—

Kidney transplant with grafts containing multiple renal arteries rather than grafts with a single renal artery does not significantly influence patient and graft outcomes.

Outcome of living kidney donors left with multiple renal arteries

Individuals with kidneys having ≥ 2 arteries appear to have an increased incidence of hypertension. Whether kidney donors in whom the remaining kidney has ≥ 2 arteries are at increased risk of hypertension is unknown. Therefore, we studied 3685 kidney donors to determine whether donors left with a kidney having ≥ 2 arteries were at increased risk of hypertension, impaired renal function, or death. Cohorts were assigned based on our practice pattern and the anatomy of the donated kidney. Of the 3685 donors, 1211 were estimated to have a remaining kidney with ≥ 2 arteries. Mean follow-up time for the single-artery group was 14.1 (± 11.0) yr and 15.3 (± 11.2) yr for the ≥ 2 artery group. Six-month hospital readmission rate was 1.4% and 1.2%, hypertension was noted in 22.4% and 21.8% and proteinuria in 9.7% and 9.6%, and estimated glomerular filtration rate at last follow-up was 62 (± 28) and 62 (± 16) for single vs. ≥ 2 renal artery groups, respectively. Our data suggest no adverse clinical sequelae nor any decrease in long-term survival for donors left with a kidney having ≥ 2 renal arteries.

Vascular anomaly in bilateral ectopic kidney: a case report

Ectopic kidney occurs as a result of a halt in migration of kidneys to their normal locations during embryonal period. While kidneys ascend through pelvis, they receive new branches from vessels (iliac and aorta) close to them. When they reach the highest point, they receive new branches from aorta and the former branches degenerate. Renal vessels do not degenerate in the ectopic caudal kidney, more than one accessory and polar arteries may arise. In various studies, a possibility of association between presence of multiple renal arteries and hypertension, has been reported. We aimed to present a case with bilateral ectopic kidney and vascular anomaly associated with hypertension and renal dysfunction.

Living donor kidney transplantation

Living donor kidney transplantation is the optimum treatment for the uremic patient. Successful kidney transplantations started in 1953 in Boston and in Sweden in 1964. This article showed data on the selection of the donor, surgical techniques for the removal of the kidney, and follow-up of short-term complications. The long-term results included the number of donors who developed hypertension and the few donors who developed end-stage renal failure (ESRF) and the reasons for this. Finally, new groups of donors such as blood group-incompatible donors and anonymous donors have been accepted, each of whom have their own programs. This article also discussed our responsibilities as renal specialists or transplant surgeons for kidney donors at surgery and postsurgery.

Accessory Renal Arteries Are Not Related to Hypertension Risk:A Review of MR Angiography Data

OBJECTIVE

It has been hypothesized that accessory renal arteries are related to the risk of hypertension. Our goal was to determine the prevalence of accessory renal arteries in hypertensive patients using MR angiography and to assess the relationship between accessory renal arteries and hypertension risk.

MATERIALS AND METHODS

From 1996 to 2002, 185 hypertensive patients underwent MR angiography of the renal arteries at our institution for assessment of renal artery stenosis. MR angiograms were obtained using a 1.5-T magnet, IV gadolinium, and 3D gradient-echo sequences. Interpretations of the MR angiograms were retrospectively reviewed.

RESULTS

Of 185 hypertensive patients, 45 (24%) showed accessory renal arteries. Of these 45 patients, nine (20%) showed renal artery stenosis and 36 (80%) showed no significant stenosis. Of the 140 patients with a single renal artery, 42 (30%) showed renal artery stenosis and 98 (70%) showed no stenosis. The odds ratio of renal artery stenosis in the accessory renal artery group versus the single renal artery group was 0.58 (95% confidence interval, 0.26-1.3%), which is not statistically significant at a power of 0.85 (chi(2) = 1.705; p = 1.0).

CONCLUSION

We found no statistically significant difference in the prevalence of renal artery stenosis between patients with accessory renal arteries and those without accessory renal arteries. Assuming that the presence of two separate causes of hypertension in the same patient would be unlikely, this finding implies that accessory renal arteries are a vascular anomaly and not a direct cause of hypertension. The findings are potentially relevant in refuting the theory of accessory renal arteries as an anatomically treatable cause of hypertension.

Multiple variations of abdominal vessels in a single cadaver

Variations of abdominal vessels are common and there are many reports about this subject. We report numerous variations of the superior part of the abdominal aorta and renal vessels which were determined in a single cadaver.