Hypertension associated with multiple renal arteries may be renin-dependent

Multiple Treatment Strategies of Accessory Renal Artery Related Hypertension: Report of Two Cases and Literature Review

Renovascular hypertension (RVH) is a primary cause of secondary hypertension, primarily driven by the activation of the renin-angiotensin-aldosterone system activation. Recently, growing studies suggested accessory renal artery (ARA) might also contribute to RVH. However, the treatment of ARA-related hypertension and whether to take interventional treatment lack consensus. Herein, we report two cases of ARA-related hypertension in our hospital. Imaging studies of both patients showed ARA stenosis. One patient had ARA occlusion well-compensated through tortuous collateral branches, achieving normal blood pressure by medical treatment alone. The other patient had ARA stenosis coexisted with main renal artery stenosis, and revascularization of both arteries led to a significant postoperative reduction in blood pressure. A literature review was conducted to summarize overall treatment strategies for ARA-related hypertension and clarify the relationship between ARA and hypertension. Recent research supported an association between ARA and hypertension. While medical therapy remains the first-line treatment for ARA-related hypertension, interventional procedures should be considered for patients whose blood pressure remains uncontrolled despite conservative management.

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.

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 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.

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.

The Renal Vasculature: What the Radiologist Needs to Know

The physiologic role of the kidneys is dependent on the normal structure and functioning of the renal vasculature. Knowledge and understanding of the embryologic basis of the renal vasculature are necessary for the radiologist. Common anatomic variants involving the renal artery (supernumerary arteries and prehilar branching) and renal vein (supernumerary veins, delayed venous confluence, retroaortic or circumaortic vein) may affect procedures like renal transplantation, percutaneous biopsy, and aortic aneurysm repair. Venous compression syndromes (anterior and posterior nutcracker syndrome) can be symptomatic and can be diagnosed with a combination of radiologic features. Renal artery stenosis is commonly atherosclerotic and is diagnosed with Doppler US, CT angiography, or MR angiography. Fibromuscular dysplasia, the second most common cause of renal artery narrowing, has a characteristic string-of-beads appearance resulting from multifocal stenoses and dilatations. Manifestations of renal vasculitis differ depending on whether the affected vessels are large, medium, or small. Renal vascular injury is graded according to the American Association for the Surgery of Trauma (AAST) renal injury scale, which defines vascular injury and active bleeding in renal injuries. Both renal arteries and veins are affected by primary neoplasms or secondarily by neoplasms from adjacent structures. Differentiation between bland thrombus and tumor thrombus and the extent of involvement dictate management in malignancies, especially renal cell carcinoma. Aneurysms, pseudoaneurysms, arteriovenous malformations, and arteriovenous fistulas can affect renal vessels and can be diagnosed with specific imaging features. The radiologist has a critical role in identification of specific imaging characteristics and establishing the diagnosis in the varied pathologic conditions affecting the renal vasculature, which is critical for directing management. Thus, the renal vasculature should be an integral part of radiologists' checklist. ^©RSNA, 2021.

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.

Renal Innervation in Resistant Hypertension: A Review of Pathophysiology and Renal Denervation as Potential Treatment

Background

Advances in treatment and increased awareness have improved the prognosis for many patients with hypertension (HTN). Resistant hypertension (RH) refers to a subset of hypertensive individuals who fail to achieve a desired blood pressure (BP) despite concurrent use of 3 different classes antihypertensive agents, one being a diuretic, and proper lifestyle changes. The prevalence and prognosis of RH are unclear owing to its heterogeneous etiologies, risk factors, and secondary comorbidities. Previous research has provided evidence that increased renal sympathetic nerve activity (RSNA) within the renal artery contributes to RH development. Renal denervation (RDN) is a procedure that attempts to ameliorate the effects of heightened RSNA via ablation renal sympathetic fibers. BP reductions associated with RDN may be attributed to decreased norepinephrine spillover, restoration of natriuresis, increasing renal blood flow, and lowering plasma renin activity. Early clinical trials perpetuated positive results, and enthusiasm grew exponentially. However, recent clinical trials have called into question RDN's efficacy. Numerous limitations must be addressed to discern the true effectiveness of RDN as a therapeutic option for RH.

Objective

We aimed to review the current understanding of RH, the anatomy of renal arteries, physiology of RH on renal arteries, anatomical pathways of the sympathetic involved in RH, RDN as a treatment option, and all relevant clinical trials treating RH with RDN.

Methods

We piloted a MEDLINE^® database search of literature extending from 1980 to 2017, with emphasis on the previous five years, combining keywords such as “resistant hypertension” and 
“renal denervation.”

Conclusion

A plethora of information is available regarding heightened RSNA leading to RH. RDN as a possible treatment option has shown a range of results. Reconciling RDN's true efficacy requires future trials to increased sites of nerve ablation, standardized protocol, increased anatomical understanding per individual basis, stricter guidelines regarding study design, increased operator experience, and integrating the use of a multielectrode catheter.

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.

Persistent Increase in Blood Pressure After Renal Nerve Stimulation in Accessory Renal Arteries After Sympathetic Renal Denervation

Blood pressure response to renal denervation is highly variable, and the proportion of responders is disappointing. This may be partly because of accessory renal arteries too small for denervation, causing incomplete ablation. Renal nerve stimulation before and after renal denervation is a promising approach to assess completeness of renal denervation and may predict blood pressure response to renal denervation. The objective of the current study was to assess renal nerve stimulation–induced blood pressure increase before and after renal sympathetic denervation in main and accessory renal arteries of anaesthetized patients with drug-resistant hypertension. The study included 21 patients. Nine patients had at least 1 accessory renal artery in which renal denervation was not feasible. Renal nerve stimulation was performed in the main arteries of all patients and in accessory renal arteries of 6 of 9 patients with accessory arteries, both before and after renal sympathetic denervation. Renal nerve stimulation before renal denervation elicited a substantial increase in systolic blood pressure, both in main (25.6±2.9 mm Hg; P <0.001) and accessory (24.3±7.4 mm Hg; P =0.047) renal arteries. After renal denervation, renal nerve stimulation–induced systolic blood pressure increase was blunted in the main renal arteries (Δ systolic blood pressure, 8.6±3.7 mm Hg; P =0.020), but not in the nondenervated renal accessory renal arteries (Δ systolic blood pressure, 27.1±7.6 mm Hg; P =0.917). This residual source of renal sympathetic tone may result in persistent hypertension after ablation and partly account for the large response variability.

Retrospective morphometric study of the suitability of renal arteries for renal denervation according to the Symplicity HTN2 trial criteria

OBJECTIVE

The aim of this study was to describe the renal arteries of humans in vivo, as precisely as possible, and to formulate an expected value for the exclusion of renal denervation due to the anatomical situation based on the criteria of the Symplicity HTN trials.

DESIGN AND SETTING

In a retrospective cohort study, the renal arteries of 126 patients (57 women, 69 men, mean age 60 ± 17.2 years (CI 57.7 to 63.6)) were segmented semiautomatically from high-contrast CT angiographies.

RESULTS

Among the 300 renal arteries, there were three arteries with fibromuscular dysplasia and one with ostial renal artery stenosis. The first left renal artery was shorter than the right (34 ± 11.4 mm (CI 32 to 36) vs 45.9 ± 15 mm (CI 43.2 to 48.6); p<0.0001), but had a slightly larger diameter (5.2 ± 1.4 mm (CI 4.9 to 5.4) vs 4.9 ± 1.2 mm (CI 4.6 to 5.1); p>0.05). The first left renal arteries were 1.1 ± 0.4 mm (CI 0.9 to 1.3), and the first right renal arteries were 0.3 ± 0.6 mm (CI 0.1 to 0.5) thinner in women than in men (p<0.05). Ostial funnels were up to 14 mm long. The cross-sections were elliptical, more pronounced on the right side (p<0.05). In 23 cases (18.3%), the main artery was shorter than 2 cm; in 43 cases (34.1%), the diameter was not >4 mm. Some 46% of the patients, or 58.7% when variants and diseases were taken into consideration, were theoretically not suitable for denervation.

CONCLUSIONS

Based on these precise measurements, the anatomical situation as a reason for ruling out denervation appears to be significantly more common than previously suspected. Since this can be the cause of the failure of treatment in some cases, further development of catheters or direct percutaneous approaches may improve success rates.

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.

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.

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.

Frequency of renal artery stenosis and variants of renal vascularization in hypertensive patients: analysis of 1550 angiographies in one centre

Renal artery stenosis (RAS) is an important cause of arterial hypertension and chronic kidney disease. The aims of our study were to assess the prevalence of RAS and to examine the frequency of variants of renal vasculature, that is, multiple and/or accessory renal arteries in hypertensive patients referred to renal angiography. We evaluated retrospectively 1554 arteriographies of hypertensive patients. Angiograms were evaluated to find RAS, significant RAS (>60% stenosis of the lumen), radiological signs of atherosclerosis, aneurysms of the renal arteries or aorta and variants of kidney vascularization. The frequency of RAS including occlusions was 15.1% (21.3% of them were significant and suitable for revascularization). Variants of renal arterial vascularization were found in 26.5% of patients (multiple renal arteries-11.2% and accessory renal arteries-15.3%). Significant RAS was found more frequently in patients older than 60 years-OR 4.76 (2.08-10.86). Coronary artery disease, history of myocardial infarction or stroke significantly increased the chance of RAS detection. The frequency of renal accessory arteries was lower in patients older than 60 years and in patients with the radiological signs of atherosclerosis. Results of this study indicate that haemodynamically important RAS is found more frequently in hypertensive patients older than 60 years. Symptomatic atherosclerotic disease found in the peripheral and/or coronary arteries and diabetes mellitus increases the chance of RAS detection. Decreased occurrence of renal accessory arteries was found in hypertensive patients with radiological signs of atherosclerosis.

Renin-Dependent Hypertension Caused by Nonfocal Stenotic Aberrant Renal Arteries

We have identified 2 relatively young patients with significant hypertension, an elongated single aberrant renal artery supplying blood to a renal segment, and evidence for localization of the elevated plasma renin activity to the side and vein draining the affected kidney. Furosemide-induced diuresis and acute oral captopril stimulated the renal vein/contralateral renin ratios to 4.3:1 and 6.5:1 in patients 1 and 2, respectively. These renal vein ratios are significantly higher than normal (>3:1 under similar conditions). Partial resection of the portion of the kidney affected by the aberrant tortuous artery led to a marked reduction in blood pressure in patient 1. Patient 2, not an operative candidate, responded satisfactorily to use of a converting enzyme inhibitor, which helped to confirm the dependency of the blood pressure on the abnormal flow relationship existing within that aberrant artery and the kidney. We believe these 2 patients are representative of a small but distinct subgroup within the larger number of patients with elongated single or multiple renal aberrant arteries. Each aberrant artery had no focal stenosis, although a decrease in flow relative to the tissue perfusion demands was apparent from the marked activation of the renin-angiotensin system in the venous system draining that artery. The increased length of such vessels may contribute to their decreased flow, although their average diameter may reside just above such a critical value for a normal length vessel. This new syndrome, involving more than one component of the flow/resistance relationship, has been overlooked when renin-dependent forms of hypertension are considered.

Renal arteriographic data of young male patients with suspected renovascular hypertension

The aim of the study was to determine whether the anatomical variant in which one or more renal vessels arose from the aorta was associated with hypertension in young male patients. We investigated the renal arteriographic data of 73 young male patients (age: 27.4 +/- 7.4, blood pressure: 162.7 +/- 17.5/104.6 +/- 10.1 mmHg) with grade-II hypertension. All studied patients underwent angiography to exclude renal artery stenosis. The patients were divided into two groups on the basis of their renal angiograms. We determined no abnormal findings in 33 renal arteriograms (45.2%). Twenty three (31.5%) patients had an additional renal artery without renal artery stenosis or renal anatomical variations. In conclusion, although the significance of this form of hypertension is still largely obscure, we believe that the presence of additional renal arteries may be associated with hypertension.

Congenital familial vascular anomalies: a study of patients with an anomalous inferior vena cava, and of their first-degree relatives

With magnetic resonance angiography and computed tomography, congenital anomalies of the inferior vena cava are diagnosed more frequently than they used to be. Accessory renal arteries identified by magnetic resonance angiography in a patient with an anomalous inferior vena cava indicated a combination of arterial and venous abnormalities. The study was initiated to screen consecutive patients with an anomalous inferior vena cava for concomitant abdominal and pelvic arterial abnormalities, and their first-degree relatives for congenital vascular anomalies. Magnetic resonance angiography identified in 2 of 5 patients with an anomalous inferior vena cava concomitant accessory renal arteries and in 5 of 11 first-degree relatives major abdominal vascular anomalies including accessory renal arteries, accessory renal veins, and anomalies of the hepatic artery. None of the relatives showed abnormalities of the inferior vena cava. The familial occurrence of vascular anomalies strongly suggests an underlying pathogenetic component in affected family members. In patients with a congenital anomaly of the inferior vena cava, concomitant arterial abnormalities should be considered. First-degree relatives may be at risk for congenital vascular anomalies.