Successful treatment of renovascular hypertension due to fibromuscular dysplasia by intravascular ultrasound-guided atherectomy

A 22-year-old man presented with renovascular hypertension, based on a stenosis of the distal portion of the right renal artery with a "string of beads"-like appearance. An intravascular ultrasound image at the renal artery lesion revealed irregularity of the vascular wall. Directional atherectomy was performed and histopathology of atherectomised tissues showed medial fibroplasia, a common type of fibromuscular dysplasia. After atherectomy his hypertension was markedly improved. We report here a case of renovascular hypertension due to fibromuscular dysplasia, successfully diagnosed and treated with IVUS-guided renal atherectomy.     

Prevalence and predictors of renal artery stenosis in patients undergoing peripheral and coronary angiography

Background

Renal artery stenosis is a potential cause of secondary hypertension, ischemic nephropathy and end-stage renal disease. Atherosclerosis is by far the most common etiology of renal artery stenosis in elderly. We investigated whether the presence of significant atherosclerotic renal artery stenosis (ARAS) with luminal diameter narrowing ≥50 % could be predicted in patients undergoing peripheral and coronary angiography.

Methods

The records of 3,500 consecutive patients undergoing simultaneous renal angiography along with peripheral and coronary angiography were reviewed. The patients with known renal artery disease were excluded.

Results

Prevalence of ARAS was 5.7 %. Significant ARAS (luminal diameter narrowing ≥50 %) was present in 139 patients (3.9 %). Hypertension with altered serum creatinine and triple-vessel CAD were associated with significant renal artery stenosis in multivariate analysis. No significant relationship between the involved coronary arteries like left anterior descending, left circumflex, right coronary artery and ARAS was found. Only hypertension and altered serum creatinine were associated with bilateral ARAS. Extent of CAD or risk factors like diabetes, hyperlipidemia or smoking did not predict the unilateral or bilateral ARAS.

Conclusion

Prevalence of ARAS among the patients in routine cardiac catheterization was 5.7 %. Hypertension is closely associated with significant ARAS. Significant CAD in the form of triple-vessel disease and altered renal function tests are closely associated with ARAS. They predict the presence of significant renal artery stenosis in patients undergoing routine peripheral and coronary angiography. Moreover, hypertension and altered renal functions predict bilateral ARAS.     

Concomitant renal revascularization in patients undergoing aortic surgery

Sixty-three patients who underwent renal revascularization at the time of aortic surgery were retrospectively reviewed. These patients had significant renal artery stenosis in addition to either severe aortoiliac occlusive disease or aortic aneurysmal disease. Fifty-eight patients were hypertensive, whereas five patients were normotensive and these renal lesions were treated prophylactically. The operative mortality rate was 3%. Despite lack of selectivity in these patients with diffuse atherosclerosis, 60% (35 of 58) of the patients with hypertension could be classified as either "cured" or "improved." Patients with bilateral renal artery involvement and moderate azotemia were noted to improve with respect to renal function postoperatively. No patient has required chronic dialysis at a mean follow-up period of 22.6 months. Simultaneous aortic and renal artery surgery may be performed with low morbidity and mortality rates and produce a gratifying improvement in hypertension. Renal functional improvement and perhaps preservation of renal mass may be anticipated in selected patients.     

Roentgenoendovascular dilatation of the renal arteries in the treatment of vasorenal hypertension

The possibilities of the use of roentgenoendovascular dilatation of the renal artery were studied in 57 patients with stenosis of the renal artery and vasorenal hypertension. The authors managed to perform the manipulation in 48 patients. Occlusion of the renal artery, pronounced atherosclerosis of the iliac and axillary arteries, coarctation of the aorta were the causes of failure. In 52.6% of the patients, the "residue" of stenosis was less than 30% of the normal arterial lumen, in 31.6%--30-50%, in the remaining patients, the dilatation has failed. Stable normotension was achieved in 39.5%, the state improved in 50% of the patients. The absence of hypotensive effect for the first 6 mos after the operation was caused by recurrency of the dilated artery stenosis, which resulted from the improper choice of a balloon catheter. The diameter of such a catheter should be 100-110% of a width of the renal arterial lumen proximally to stenosis. The later recurrency of hypertension was caused by the development of the stenosis of the artery of the contralateral kidney.     

Post-Transplant Renal Artery Stenosis: Impact of Therapy on Long-Term Kidney Function and Blood Pressure Control

Purpose

We assessed the long-term outcome of different treatment methods for transplant renal artery stenosis.

Materials and Methods

Outcome data for 23 patients with transplant renal artery stenosis treated during a 16-year period were reviewed and analyzed.

Results

There was a higher incidence of renal artery stenosis in cadaveric donor kidneys compared to living donor kidneys (2 percent versus 0.3 percent, p less than 2), and in cadaveric kidneys from pediatric donors less than 5 years old compared to those from adults (13.2 percent versus 1.3 percent, p less than 0.01). Six patients underwent primary medical treatment for renal artery stenosis, with a successful outcome in 4 (mean followup plus or minus standard error 57 plus/minus 22 months) and failure in 2. Of the patients 16 were treated with percutaneous transluminal angioplasty, including 12 who were cured or improved with respect to hypertension (followup 44.7 plus/minus 7.6 months). Five patients underwent surgical revascularization for renal artery stenosis with postoperative improvement of hypertension (followup 18.8 plus/minus 11.6 months). Overall, 21 of 23 patients (91 percent) were treated successfully for transplant renal artery stenosis with cure or improvement of associated hypertension. Posttreatment renal function was stable or improved in 18 patients, while renal function deteriorated due to parenchymal disease in 3.

Conclusions

Most patients with transplant renal artery stenosis can be treated successfully. Percutaneous transluminal angioplasty is the initial interventive treatment of choice for high grade renal artery stenosis. Surgical revascularization is indicated if percutaneous transluminal angioplasty cannot be done or is unsuccessful.     

Renal artery revascularisation can restore kidney function with absent radiotracer uptake

Background

Children with renovascular hypertension often present with severe hypertension. Some children have severe obstruction of their renal arteries resulting in <10% relative function on [^99mTc]dimercaptosuccinic acid (DMSA) scan. Conventional treatment of these children has been nephrectomy of the poorly functioning kidney to normalise their blood pressure (BP).

Case-Diagnosis/treatment

We describe three children aged 20 months to 9 years with severe renal artery stenosis and severe hypertension who had radionucleotide uptake of 0% in one kidney. In one case, no renal perfusion was demonstrated by duplex ultrasound scan. Significant recovery of relative renal function of 18 to 52% was achieved after revascularisation by percutaneous angioplasty or open surgery of the obstructed renal artery.

Conclusion

These cases illustrate that scintigraphy alone cannot be used to predict salvageable function in children with renovascular disease.     

Is duplex scanning the best screening test for renal artery stenosis?

Screening for renal artery stenosis is indicated in patients with suspected renovascular hypertension or ischemic nephropathy to identify those who could benefit from renal artery interventions. The critical requirements for a clinically useful screening test include safety, low cost, and a high sensitivity or low false-negative rate. Arteriography remains the "gold standard" for the anatomic diagnosis of renal artery disease, but it is unsuitable for screening because of its high cost and invasive nature. Although renal duplex scanning technically is difficult, experienced laboratories have been able to achieve sensitivities and specificities in the range of 93% to 98% for identification of stenoses in the main renal arteries. Renal duplex scanning also provides a method for assessing the renal parenchyma and predicting the clinical outcome of renal revascularization. The principal limitation of renal duplex scanning is failure to identify accessory renal arteries. The finding of one or more widely patent main renal arteries makes ischemic nephropathy unlikely, because this condition results from "total" renal ischemia. However, renovascular hypertension can be present with normal main renal arteries when there are isolated stenoses involving accessory renal arteries, so further testing may be indicated in selected hypertensive patients with normal main renal arteries by duplex scanning. Currently, duplex scanning in a qualified vascular laboratory arguably is the best screening test for renal artery stenosis. Other methods for assessing the renal arteries, particularly spiral computed tomography and magnetic resonance angiography, are evolving rapidly and also may play a role in screening of selected patients.     

Plasma renin activity revealed renal artery stenosis concealed by aneurysms

We describe a case of renovascular hypertension with renal artery stenosis concealed by aneurysms. Arteriography demonstrated no apparent renal artery stenosis, but did reveal aneurysms on the left renal artery. Captopril-loaded renoscintigraphy could not detect disturbed renal perfusion. High basal and exaggerated plasma renin activity after captopril administration were the only clues indicating renovascular hypertension. A reduction of the systemic blood pressure and normalized plasma renin activity after resection of the aneurysms confirmed preoperative renovascular hypertension. Fibromuscular dysplasia was an underlying cause of the arterial deformity. In cases of hypertension accompanied by renal artery aneurysms, the captopril-challenge test can be a useful tool to detect renal artery stenosis concealed by the aneurysms.     

Extraparenchymal Renal Artery Aneurysms: Is Hypertension an Indication for Revascularization Surgery?

We report here the surgical management of extraparenchymal renal artery aneurysms associated with hypertension and the results of this treatment. From January 1978 through December 1999, 19 consecutive patients with 23 extraparenchymal renal artery aneurysms underwent surgery with renal revascularization techniques. Of these 19 patients, 89.5% had systemic hypertension, and 12 of 16 patients had associated renovascular hypertension. Twenty of the aneurysms were patent, one was chronically thrombosed, and one patient presented with acute thrombosis of abdominal aortic and bilateral renal aneurysms; 11 of the 20 patent cases had significant stenosis in the preoperative arteriography. Seventeen aneurysms (74%) were located on the main trunk of the renal artery. Response of hypertension and renal function were examined. Surgical technique patency was evaluated by life-table methods. Our basic surgical indication for extraparenchymal renal artery aneurysms in this series was renovascular hypertension. Nonrenal hypertension alone does not indicate surgery. We consider the saphenous vein to be the graft of choice for renal revascularization.     

Saccular renal artery aneurysm as a cause of hypertension

The case of a patient with renovascular hypertension related to an arterial kink is reported. The arterial kink was caused by a renal artery aneurysm and was not apparent with angiography. This is the first reported case in which renin-mediated hypertension was clearly related to a correctable mechanical problem from a saccular renal artery aneurysm. Indications for surgical repair of renal artery aneurysms and angiographic findings indicative of a functionally significant renal artery stenosis are reviewed.     

Trends in reconstruction for atherosclerotic renal vascular disease

Twenty-eight patients underwent renal vascular reconstruction for atherosclerotic renal vascular stenosis. Ten patients had therapeutic renal artery reconstruction for isolated renal artery stenosis causing severe hypertension, nine patients had therapeutic renal artery reconstruction for severe hypertension combined with simultaneous aortic reconstruction, and nine patients had prophylactic renal artery reconstruction for renal artery stenosis combined with simultaneous aortic reconstruction. Ninety percent of patients undergoing therapeutic renal revascularization procedures for hypertension were cured or improved. The 10 patients undergoing prophylactic renal artery reconstruction combined with aortic reconstruction had an average 72 percent reduction in the diameter of the vessel. Dacron side grafts sutured to the aortic graft were used for revascularization in each of the patients with prophylactic revascularization and was found to be an expedient means of reconstruction with good patency rates. No increased morbidity or mortality rate was noted in the prophylactic group. We believe that prophylactic revascularization should be carried out in patients with atherosclerotic high-grade stenosis of the renal arteries to prevent hypertension and preserve renal function.     

Use of the splenic and hepatic arteries for renal revascularization

During a 16-year period at the Massachusetts General Hospital 77 patients underwent 79 procedures (29 hepatorenal bypasses, 50 splenorenal arterial anastomoses) for treatment of renovascular hypertension, renal preservation, or both. The procedure was chosen primarily to avoid a diseased or scarred aorta in 41, to allow a staged approach to bilateral renal artery stenoses or multiple vascular lesions in 17, as a "lesser operation" for five poor-risk patients, for complex problems including trauma, mycotic aneurysm, aortic dissection, thoracoabdominal aneurysm, and renal artery aneurysm in five, and as the procedure of choice in 11 patients. The perioperative mortality rate was 6% for the 77 patients studied. No hepatic dysfunction was seen. Deterioration of renal function occurred on three occasions but only in patients with bilateral simultaneous repair. Cure or improvement of hypertension was achieved in 52 of 63 patients and renal function preserved or improved in 67 of 77 patients. Long-term functional results remain good during follow-up periods up to 14 years. Our experience indicates that use of the hepatic or splenic artery may provide a safe and largely successful alternative for renal revascularization in selected circumstances.     

Brachydactyly short-stature hypertension syndrome: a case with associated vascular malformations

Brachydactyly short-stature hypertension syndrome, also known as hypertension-with-brachydactyly (HTNB) syndrome, is a rare autosomal dominant disorder that was first described by Bilginturan and colleagues in 1973. Many familial cases of HTNB have been reported, but the first sporadic case of this condition was published only recently. This article describes a case of HTNB syndrome in a 16-year-old boy. Although Doppler ultrasonography of the kidneys and renal arteries showed normal findings, magnetic resonance angiography showed an aberrant right posterior inferior cerebellar artery, early bifurcation of the left renal artery, and irregularity and stenosis of the inferior dominant branch of this artery. The patients father was in chronic renal failure of which the primary pathology was unknown. We speculate that the described case is the second documented sporadic case of HTNB syndrome. This disorder should be included in the differential diagnosis of patients with short stature and hypertension of unknown aetiology. Such individuals should be carefully examined for brachydactyly and for cerebral–cerebellar and renal vascular malformations.This study was presented as a poster at the European Human Genetics Conference in Munich, Germany, on 12–15 June 2004     

The natural history of atherosclerotic and fibrous renal artery disease

Summary Individuals with atherosclerotic or fibrous renal artery disease may develop renovascular hypertension and/or renal dysfunction. Traditionally, the motivation for identifying patients with renal artery stenosis was the treatment of renovascular hypertension. However, recent interest has centered on the investigation of patients suspected of having renal artery stenosis that might account for progressive azotemia. While specific forms of fibrous and/or atherosclerotic renal artery disease can lead to a compromise in renal function, differences may exist in the age of presentation, predominat sex, angiographic appearance and overal natural history. Recognition of these differences is helpful in deciding on the most likely lesion type, appropriate workup and treatment. Since renal artery stenosis can lead to radiologic and functional alterations, clinical markers of progression, such as renal size and serum creatinine measurements, are helpful in identifying patients with advancing disease. The regulators of fibrous disease progression are less clear than those responsible for atherosclerotic progression in the renal artery. Uncontrolled systemic hypertension, intrarenal hypertension, hyperlipidemia, cigarette smoking, and obesity all may potentially contribute to progressive atherosclerosis. Individuals identified with progressive azotemia due to renal artery stenosis may benefit from improved perfusion flow by renal revascularization or balloon angioplasty provided no significant parenchymal disease is present.     

Atherosclerotic renal artery stenosis as a cause for hypertension in an adolescent patient

Background

Atherosclerosis causing renal artery stenosis (RAS) is one of the most common secondary causes of hypertension in adults, but is rare in children.

Case-diagnosis/treatment

RAS associated with coronary artery stenosis was diagnosed in a teenage patient who presented with intermittent chest pain and elevated blood pressures for 6 years. The diagnosis of RAS was suspected after physical examination revealed an abdominal bruit. Renal ultrasound with Doppler revealed normal appearing kidneys with high velocity in the aorta and renal arteries. Computed tomography angiography (CTA) of the chest and abdomen demonstrated generalized calcified atherosclerotic narrowing of the arteries including the renal, celiac, superior mesenteric and coronary arteries in the setting of hyperlipidemia. The lipid panel revealed hypercholesterolemia with elevated serum plant sterol concentrations, suggesting the diagnosis of sitosterolemia. Cardiac catheterization demonstrated left anterior descending artery and left circumflex artery stenosis, which required bypass of the left anterior descending artery and stenting of the left circumflex artery. Aggressive lipid control was recommended and he was treated medically with a beta-blocker, low-dose angiotensin-converting enzyme inhibitor, aspirin, statin, and clopidogrel.

Conclusion

Although very rare, generalized atherosclerosis caused by genetic disorders should be considered an underlying cause for severe hypertension in children with hyperlipidemia.     

Fibromuscular dysplasia of the renal artery: Management and outcome

Renovascular hypertension may be caused by atherosclerotic disease or less commonly by fibromuscular dysplasia (FMD) of the renal arteries. Fibromuscular dysplasia is the commonest cause of renal artery stenosis in the younger age group and affects women predominantly. A review of our clinical database identified all patients with renovascular hypertension. All relevant clinical, biochemical and radiological findings on those with FMD were noted. The outcome of percutaneous transluminal renal angioplasty (PTRA) or reconstructive surgery was evaluated. Eight out of 62 (13%) patients with hypertension secondary to renovascular disease had FMD (all female; bilateral in four; mean age at diagnosis 37.6 years; age range 12–70 years). The mean duration of hypertension before the diagnosis of FMD was 3.3 years (range 3 months–10 years). A renal artery bruit was detected in five, hypertensive retinopathy in three and one had mild renal insufficiency. Twelve PTRAs were attempted on 10 stenotic lesions in six women. This cured the hypertension in three, while the other three have required less antihypertensive therapy. Percutaneous transluminal renal angioplasty was complicated by a trivial renal artery dissection in one, and a small upper pole infarction in another. One patient required a repeat PTRA. The other two women presented before the availability of PTRA and had successful reconstructive surgery. Fibromuscular dysplasia was the cause of hypertension in eight out of 62 (13%) patients with renovascular hypertension. Percutaneous transluminal renal angioplasty has shown encouraging results with a low complication rate. If technically feasible, PTRA should be attempted on all patients with FMD of the renal artery.     

Traumatic renal arteriovenous fistula: case report and useful operative technique.

A patient with a traumatic extrarenal arteriovenous fistula underwent successful repair of the lesion. The reconstruction utilized a portion of renal vein to allow lateral repair of the renal artery. The patient's postoperative course was complicated by paradoxical hypertension and severe abdominal pain like that in the "post-coarctectomy syndrome." Satisfactory recovery has occurred and the patient remains normotensive.     

Is incidental renal arteriography justified in a population of patients with symptomatic peripheral arterial disease?

Renal artery stenosis is a consequence of generalized atherosclerosis and many specialists perform routine selective renal angiography to detect and treat renal artery stenosis. The incidence of clinically important renal artery stenosis is not well defined in patients with symptomatic peripheral arterial disease. The purpose of this study was to better delineate the incidence of and the risk factors associated with renal artery stenosis, renovascular hypertension, and ischemic nephropathy incidentally discovered during angiography for symptomatic peripheral arterial disease. Two hundred consecutive patients undergoing angiographic evaluation of symptomatic lower extremity peripheral arterial disease were studied retrospectively. Angiograms were reviewed for the presence of renal artery stenosis (defined as >or= 25% diameter reduction in either renal artery) and findings were then correlated to the clinical diagnosis of renovascular hypertension (> 50% renal artery stenosis and >or= 3-drug resistive hypertension) and ischemic nephropathy (defined as > 50% bilateral renal artery stenosis, 3-drug hypertension, and creatinine >or= 1.5). Angiographic findings were also correlated with risk factors to determine if a relationship correlated to the presence of and degree of renal artery stenosis. Data were analyzed using the Student's t test, Chi-square model, and multiple logistic regression analysis. The overall incidence of any degree of renal artery stenosis in this study population was 26% (52 patients). Only 24 (12%) patients had an incidental finding of >or= 50% stenosis in either renal artery. Six (3%) of these patients were found to have associated renovascular hypertension. Additionally, 9 (4.5%) patients had coexistent renal insufficiency and significant renal artery stenosis; five with end-stage renal disease on chronic hemodialysis. Only one patient with end-stage renal disease had poorly controlled 3-drug hypertension. Thus definitive ischemic nephropathy was present in only one (0.5%) patient. Statistically significant risk factors associated with the presence of renal artery stenosis include hypertension (P < .001), coronary disease (P = .024), female gender (P = .010), diabetes (P = .039), aorto-iliac disease (P = .031), multiple levels of peripheral arterial disease (P < .001), and age over 60 ( P < .001). While the incidence of renal artery stenosis in patients being evaluated for symptomatic peripheral arterial disease is similar to that reported in the cardiology literature, the incidence of renovascular hypertension and ischemic nephropathy is exceedingly low (3% and 0.5%, respectively)-findings similar to data reported in the general hypertensive population. These data suggest that incidental selective renal angiography is not justified in patients with symptomatic peripheral arterial disease.     

Persisting hypertension after renal artery reconstruction. A follow-up study.

Twenty-four patients with persisting hypertension after renal artery reconstruction were re-investigated 1--8 years after surgery. They underwent renal arteriography, determination of plasma renin activity, renography and renal function studies in order to find the causes of the postoperative hypertension. Restenosis was found in 6 patients, in 3 of whom it was of functional significance according to the positive renin tests (renin ratio greater than 1.5). Positive renin tests were found in 2 other patients. One had occlusion of a renal artery branch and the other hypoplasia of the kidney due to chronic nephritis. No explanation of the persisting hypertension could be found in 19 patients at re-examination. In 10 of them, however, biopsy from the affected kidney obtained during operation showed nephrosclerosis, which may explain the outcome. Fourteen of the 19 patients had negative renin tests preoperatively. These negative tests indicate that renal artery stenosis was not the only cause of hypertension. It may be concluded that the renin test is of the utmost value in the selection of patients for renal artery reconstruction and should always be considered. A biopsy from the contralateral kidney may be necessary in order to detect other causes of hypertension than renal artery stenosis. The importance of re-investigating patients with persisting hypertension is confirmed by the present study.     

Early diagnosis and management of renovascular hypertension

Renovascular hypertension is more common in hypertensive children than in hypertensive adults, and renal artery stenosis is second only to coarctation of the thoracic aorta as a cause of surgically correctable hypertension. Three infants presented with uncontrollable hypertension secondary to renal artery thrombosis due to umbilical artery catheterization for respiratory distress in the neonatal period. They all responded to nephrectomy. A fourth infant had stenosis of a polar vessel secondary to umbilical artery catheterization and was cured by partial nephrectomy. Two infants with renal artery stenosis secondary to fibromuscular dysplasia benefited from revascularization and, at last follow-up, were normotensive and off all blood pressure medication. Ultrasonography, isotope scanning, angiography and selective renal vein renin assays should be used to identify patients with surgically correctable lesions. The use of fine suture material and microvascular surgical techniques, including ex vivo revascularization and autotransplantation, can salvage renal parenchyma and relieve hypertension. Infants with less than 10 percent renal function on the involved side should have a nephrectomy. The infant with an umbilical arterial catheterization line needs blood pressure monitoring and aggressive evaluation and treatment of persistent hypertension.