HYPERTENSION AND MULTIPLE RENAL ARTERIES

Accessory renal arteries - a source of hypertension: A case report

BACKGROUND

Secondary hypertension is a relatively rare condition most commonly caused by renovascular disease due to atherosclerotic vascular disease or fibromuscular dysplasia. Although accessory renal arteries are frequent, to date, only six cases of secondary hypertension determined by their existence have been reported.

CASE SUMMARY

We describe a case of a 39-year-old female who came to the emergency department with an urgent hypertensive crisis and hypertensive encephalopathy. Despite normal renal arteries, the computed tomography angiography revealed an inferior polar artery with 50% stenosis of its diameter. Conservative treatment with amlodipine, indapamide and perindopril was adopted, leading to blood pressure control within one month.

CONCLUSION

To the best of our knowledge, there are controversies regarding accessory renal arteries as a potential etiology for secondary hypertension, but the seven similar cases already described, along with the current case, could reinforce the necessity of more studies concerning this subject.

Relationship between Accessory Renal Artery and Clinical Characteristics of Middle-Aged Patients with Primary Hypertension

Objectives

The association between accessory renal artery (ARA) and hypertension remains not fully understood. We observed the association between ARA and clinical characteristics among middle-aged patients with primary hypertension.

Methods

One hundred and sixty-two middle-aged (mean 39.82 ± 10.25 years, 58.0% male) patients with primary hypertension were enrolled, and patients underwent Computed Tomography Angiography (CTA) of renal arteries, ambulatory blood pressure monitor (ABPM), echocardiography, physical examination, and routine blood chemistry examinations. According to the CTA results, patients were divided into a non-ARA (n = 108) and ARA (n = 54) group. Direct renin concentration (DRC), plasma aldosterone concentration (PAC), ABPM, echocardiography, creatinine, and glomerular filtration rate were compared between the two groups.

Results

DRC (mU/L) (11.21 (5.34, 20.87) vs. 18.24 (10.32, 33.59), P=0.002) was significantly higher in the ARA group than in the non-ARA group. However, PAC (ng/dL) (98.30 (67.30, 134.00) vs. 116.50 (78.80, 137.25), P=0.103) was similar between these two groups. ABPM (mmHg) results showed that daytime (146.75 ± 17.04/95.86 ± 11.39 vs. 155.50 ± 14.76/100.48 ± 10.69, P < 0.05), night time (133.44 ± 17.50/85.28 ± 12.80 vs. 139.81 ± 14.64/89.83 ± 11.21, P < 0.05), and 24 h blood pressure (143.95 ± 15.99/93.90 ± 11.78 vs. 152.07 ± 13.85/98.11 ± 10.36, P < 0.05) were significantly higher in the ARA group than in the non-ARA group. Accordingly, echocardiographic-derived posterior left ventricular wall thickness value was higher in the ARA group than in the non-ARA group.

Conclusion

ARA is related to higher blood pressure and higher direct renin concentration in middle-aged patients with primary hypertension, and these patients deserve stricter blood pressure control. Our results provide important evidence for that ARA is a cause of hypertension and target organs damages.

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 artery anatomy affects the blood pressure response to renal denervation in patients with resistant hypertension

BACKGROUND

Renal denervation (RDN) has been shown to reduce blood pressure (BP), muscle sympathetic nerve activity (MSNA) and target organ damage in patients with resistant hypertension (RH) and bilateral single renal arteries. The safety and efficacy of RDN in patients with multiple renal arteries remains unclear.

METHODS

We measured office and 24-hour BP at baseline, 3 and 6 months following RDN in 91 patients with RH, including 65 patients with single renal arteries bilaterally (group 1), 16 patients with dual renal arteries on either one or both sides (group 2) and 10 patients with other anatomical constellations or structural abnormalities (group 3). Thirty nine out of 91 patients completed MSNA at baseline and follow-up.

RESULTS

RDN significantly reduced office and daytime SBP in group 1 at both 3 and 6 months follow-up (P<0.001) but not in groups 2 and 3. Similarly, a significant reduction in resting baseline MSNA was only observed in group 1 (P<0.05). There was no deterioration in kidney function in any group.

CONCLUSION

While RDN can be performed safely irrespective of the underlying renal anatomy, the presence of single renal arteries with or without structural abnormalities is associated with a more pronounced BP and MSNA lowering effect than the presence of dual renal arteries in patients with RH. However, when patients with dual renal arteries received renal nerve ablation in all arteries there was trend towards a greater BP reduction. Insufficient renal sympathetic nerve ablation may account for these differences.

Risk factors for perioperative complications in hand-assisted laparoscopic donor nephrectomy

Living donor kidney transplant is the preferred treatment for end-stage renal disease; however, the shortage of kidney donors remains a big problem. One of the major reasons for the shortage of living donors is the risk of potentially serious surgical complications of a procedure in which the donor has no personal medical benefit. Therefore it is important to understand the risk factors for perioperative complications associated with donor nephrectomy. Hand-assisted laparoscopic donor nephrectomy is the preferred approach for kidney procurement in many medical centers. This review gives an overview of the risk factors in donor nephrectomy and more specifically in hand-assisted laparoscopic donor nephrectomy.

Renal denervation in multiple renal arteries

BACKGROUND

In most previous studies investigating efficacy of renal denervation (RDN), patients with multiple renal arteries are generally excluded from treatment. This study was designed to determine the prevalence of multiple renal arteries in patients referred for RDN, to propose a classification for anatomical eligibility and to investigate the relation between the presence of multiple arteries and blood pressure (BP)-lowering effect.

MATERIALS AND METHODS

Patients referred for RDN who underwent noninvasive imaging of the renal arteries before treatment were included in present analysis. Eligible patients were treated. Renal function and BP were evaluated 6 months after treatment.

RESULTS

Hundred and twenty-six patients referred for RDN were included in present analysis. Thirty-four per cent had multiple arteries. Sixty-nine patients underwent RDN. Office BP significantly reduced from 195 (± 26)/106 (± 14) mmHg to 165 (± 24)/95 (± 14) mmHg (P < 0·001). BP reduction in patients with multiple arteries which were all treated was comparable to patients with solitary arteries. However, patients with multiple which were not all treated showed a trend towards a less pronounced effect of RDN (β: 11·6, P = 0·11). The proposed classification appeared useful by identifying eligible anatomy. Renal function at 6 months did not differ from baseline in all subgroups.

CONCLUSIONS

Based on our results and the high prevalence of multiple arteries, it seems reasonable not to exclude patients with multiple renal arteries from RDN. Current analysis suggests that BP reduction may be less pronounced in patients with multiple renal arteries of whom not all arteries were treated.

An investigation of the origin, location and variations of the renal arteries in human fetuses and their clinical relevance

We investigated the origin, localizations and anatomic variations of the renal artery (RA) in human fetuses with the aim of determining the distribution of these variations according to lateralization and gender. In total, 90 fetuses of spontaneous abortion (45 males, 45 females) with no congenital malformations were included to the study. The abdominal aorta and its branches were dissected after latex solution colored with red ink had been injected into the vessels from the thoracic aorta. In all, 180 RA dissections were performed bilaterally in 90 cases and the anatomic variations were photographed. Right and left RAs were found to originate from the following levels according to the columna vertebralis, respectively: 3.8% and 1.9% lower T12, 67.3% and 25.0% upper L1, 9.6% and 28.8% mid L1, 15.3% and 40.3 lower L1, 3.8% and 3.8% upper 1/3 part of L2 vertebra. The right RA originated from the lateral part and anterolateral wall of the abdominal aorta in 73.0% and 26.9% of cases while the lateral and anterolateral wall origin percentages of left RA were 90.3% and 9.6%, respectively. The origin site of the right RA from the abdominal aorta was superior to, at the same level with, and inferior to that of the left RA in 53.8%, 34.6% and 11.5% of the cases, respectively. There were no variations in 75% of the cases whereas the remaining 25% had several variation patterns. The presented morphological results are as follows: A single hilar artery in 75% of the cases, double hilar arteries in 11.1%, an inferior polar artery in 10.5%, and a superior polar artery in 3.3% of specimens studied. Anatomical variations were observed more frequently among male fetuses and on the right side. Knowledge of RA variations is important for surgeons in performing many procedures and may help to avoid clinical complications, especially, during radiological examination and/or surgical approaches in the abdominal region.

Hypertension associated with multiple renal arteries may be renin-dependent

OBJECTIVE

Subjects with multiple renal arteries have been shown to suffer more frequently from hypertension and to have higher blood pressures than subjects whose kidneys are supplied by single renal arteries. This study was carried out to determine whether subjects with multiple renal arteries also have higher renin activity.

METHODS

We studied 62 consecutive patients who had undergone angiography for various reasons. They were divided into two groups. Group A comprised 29 patients whose kidneys were supplied by single arteries (male :female ratio 1.63, mean age 51.8 +/- 1.9 years) while Group B comprised 33 patients with multiple renal arteries (male:female ratio 2, mean age 47.3 +/- 2.3 years).

RESULTS

Before stimulation with frusemide, the plasma renin in Group A was 0.79 +/- 0.13 ng angiotensin l/ml per h, while in Group B the corresponding figure was 1.73 +/- 0.38 ng angiotensin l/ml per h. This difference was statistically significant (P= 0.0127). Thirty minutes later the plasma renin level in Group A was 2.43 +/- 0.37 ng angiotensin l/ml per h versus a level of 3.86 +/- 0.53 ng angiotensin l/ml per h in Group B (P= 0.0169). Again, 30 minutes later the level was 2.59 +/- 0.4 ng angiotensin l/ ml per h in Group A, versus 3.79 +/- 0.59 ng angiotensin l/ ml per h in Group B (P= 0.0495).

CONCLUSIONS

We conclude that patients with multiple renal arteries constitute a group who have high plasma renin activity and may therefore be prone to develop arterial hypertension.

Renovascular hypertension. Secondary to traumatic occlusion of supplemental renal artery

A case is reported of documented renovascular hypertension due to traumatic occlusion of the main renal artery in a double renal artery system. Emphasis is placed on the value of the oblique renal arteriogram in assessing segmental vasuclature prior to surgical intervention. Oblique arteriography may also aid in the preoperative evaluation of patients with segmental renal ischemia due to other causes.