Distal Main Renal Artery Research Articles

Controversies in Hypertension IV: Renal Denervation

Renal denervation is not a cure for hypertension. Although more recent sham-controlled trials were positive, a significant minority of patients in each trial were unresponsive. The optimal patient or patients need to be defined. Combined systolic/diastolic hypertension appears more responsive than isolated systolic hypertension. It remains uncertain whether patients with comorbidities associated with higher adrenergic tone should be targeted, including obesity, diabetes, sleep apnea, and chronic kidney disease. No biomarker can adequately predict response. A key to a successful response is the adequacy of denervation, which currently cannot be assessed in real time. It is uncertain what is the optimal denervation methodology: radiofrequency, ultrasound, or ethanol injection. Radiofrequency requires targeting the distal main renal artery plus major branches and accessory arteries. Although denervation appears to be safe, conclusive data on quality of life, improved target organ damage, and reduced cardiovascular events/mortality are required before denervation can be generally recommended.

MON-167 TRANSPLANT RENAL ARTERY STENOSIS AS A POTENTIAL COMPLICATION AFTER KIDNEY TRANSPLANTATION FROM DONOR WITH MOYAMOYA DISEASE: A CASE REPORT

Moyamoya disease is a rare chronic cerebrovascular disorder with progressive stenosis of intracranial internal carotid arteries and their proximal branches resulting in the development of severe collateral circulations and associated with a high risk of stroke. Moyamoya disease may have extracranial manifestations such as coronary artery fistulas and stenosis, cardiac valve stenosis, congenital heart disease, and renal artery stenosis. Although organs from donors with Moyamoya disease are considered safe for transplantation, there are few reports describing the use of the organs. Here, I described the unfortunate case of kidney transplant (KT) recipient who received transplanted kidney from donor with Moyamoya disease presented with early transplant renal artery stenosis (TRAS). A 42-year-old Thai male with end-stage renal disease from unknown cause underwent KT from a 32-year-old Thai male deceased donor who was firstly diagnosed Moyamoya disease with catastrophic cerebral infarction. The KT was complicated by delayed graft function and his kidney function recovered after 2 sessions of hemodialysis. The maintenance immunosuppressive drugs included cyclosporine, mycophenolate mofetil and prednisolone. Routine Doppler ultrasound examination of transplanted kidney was done at postoperative day 7 without abnormal findings. Three months after KT, he presented with kidney allograft dysfunction, hypertension and volume overload. His serum creatinine increased from 2.08 to 5.53 mg/dL. The Cyclosporine level was within normal range. Serum BK virus and cytomegalovirus were undetectable. Kidney biopsy pathology showed diffuse ischemic tubular atrophy and interstitial edema and fibrosis without evidence of rejection. Repeat Doppler ultrasound examination of transplanted kidney revealed good transplant perfusion with a turbulent flow and a peak systolic velocity > 2 m/s at mid to distal main renal artery. Magnetic resonance angiography of transplant renal artery was also confirmed the stenosis. TRAS was diagnosed and percutaneous transluminal renal artery angioplasty (PTRA) was done without stent placement. His kidney function improved with serum creatinine of 2.53 mg/dL 2 weeks after the procedure. Then his serum creatinine increased again to the level of 5.52 mg/dL two months after the 1st procedure. PTRA was done again with renal artery stent placement. Finally, his kidney function recovered with serum creatinine of 1.72 mg/dL six month s after the 2nd procedure. Figure 2. To the best of my knowledge, this is the 1st reported case of PTRAS in KT recipient who received transplanted kidney from donor with Moyamoya disease. I believe that transplant physicians should continue using organs from donors with Moyamoya disease but must be aware of the possible extracranial complications like in my case.

An Unusual Presentation of Fibromuscular Dysplasia

Case Report A 47-year-old man developed sudden, severe left flank pain while driving, and went to a local emergency room. Initial workup included serum creatinine 1.06 mg/dl, and urinalysis negative for blood, protein, and white blood cells. Renal ultrasound was obtained and which showed left renal infarction. Computed tomography angiography revealed beading consistent with FMD at the distal main renal artery at the junction of the bifurcating branches (Figure 1) and tapered narrowing and occlusion in the more proximal artery (Figure 2) most likely caused by spontaneous dissection with intramural hematoma, with resulting substantial upper pole infarct. Diagnosis: Left renal infarction in the setting of fibromuscular dysplasia. Discussion: FMD is a non-inflammatory, non-atherosclerotic disorder that leads to arterial stenosis, occlusion, aneurysm, and dissection. Fibromuscular dysplasia (FMD) typically presents in middle aged women, often with hypertension [1]. Depending on which arteries are involved, patients may present with transient ischemic attack, headache, pulsatile tinnitus, flank pain, or stroke [2]. Computed tomography angiography, magnetic resonance angiography, duplex ultrasound and catheter based digital subtraction angiography can be ordered to confirm the diagnosis. Differential diagnosis includes atherosclerosis, polyarteritis nodosa, ehlersdanlos syndrome, marfan’s syndrome, and primary and secondary hypertension. Treatment strategies include blood pressure control, angioplasty and surgery. Conclusion: This is an atypical case of FMD in a male who presented with renal infarction. The patient had no prior history of renal disease, ehlers-Danlos syndrome, or marfan’s syndrome. The patient has done well with no anticoagulation or invasive intervention and return of renal function to his prior baseline.

Utility of color doppler ultrasound in the evaluation of renal artery stenosis in comparison with contrast-enhanced magnetic resonance angiography

Renal artery stenosis (RAS) is one of the main correctable causes of secondary systemic arterial hypertension. Color Doppler ultrasound (DUS), a non-invasive imaging modality, has been used to diagnose RAS in hypertensive patients. This study was conducted in the period between June 2008 and March 2010 to compare the sensitivity, specificity, accuracy and predictive values of DUS using contrast-enhanced magnetic resonance angiography (CEMRA) as the gold standard for the diagnosis of RAS. Fifty-seven consecutive patients with clinical findings suggestive of RAS (32 males and 25 females) with a mean age of 56 years (±7.92 years) were referred to the University Kebangsaan Medical Center to be screened for RAS using DUS and CEMRA. RAS was considered significant if the reduction in diameter was >60%. A total of 114 arteries were assessed, 65 in males (57%) and 49 in females (43%). On DUS, the parameters measured were the peak systolic velocity at the proximal main renal artery (PSV-P), distal main renal artery (PSV-D) and the suprarenal aorta (PSV-A) at the level of the renal hila and the acceleration time (AT) at the main renal artery. The renal-renal ratio (RRR), which is the value of PSV-P/PSV-D, and the renal-aortic ratio (RAR), which is the value of PSV-P/PSV-A, were then calculated. The accuracy, sensitivity, specificity and positive and negative predictive values of DUS in the detection of significant RAS were determined. All measured DUS parameters were positive for the detection of RAS, with an accuracy of 98.3%. On retrospective review, all the arteries that showed significant stenosis on CEMRA demonstrated an irregular outline on DUS. We conclude that DUS is accurate in the diagnosis of significant RAS but is not very sensitive as a screening tool.

Have We New Therapeutic Strategies in the Treatment of Renovascular Nephropathy?

Renal artery stenosis (RAS) is a cause of hypertension and ischemic nephropathy. The incidence of this disorder is probably less than 1% in patients with mild hypertension, but rises to as high as 10 to 40% in patients with acute, severe or refractory hypertension. Significant RAS can be caused by atheromatous plaques, or due to fibromuscular dysplasia (FMD). Atherosclerotic lesions are present in almost 7% of adults older than 65 years and up to 50% of patients presenting with diffuse atherosclerotic disease. In contrast to atherosclerosis, FMD most often affects women under the age of 50 and typically involves the distal main renal artery or the intrarenal branches. The optimal treatment for RAS is not yet established. Based on recent trials, we reviewed the literature on pharmacological and endovascular treatment of atherosclerotic RAS and ischemic nephropathy.

Short-Term Effects of Ankaferd Hemostat for Renal Artery Embolization: An Experimental Study

Renal artery embolization (RAE) is a minimally invasive therapeutic technique that is utilized in a number of disorders. Ankaferd is a novel hemostatic agent with a new mechanism of action independent of clotting factors. We used Ankaferd for RAE in a sheep model. Seven adult female sheep were included in the study. Selective renal arteriogram using 5-F diagnostic catheter was performed to make sure that each kidney was fed by a single renal artery and the animal had normal renal vasculature. Coaxial 2.7-F microcatheter was advanced to the distal main renal artery. Under fluoroscopic guidance, 2 mL of Ankaferd mixed with 2 mL of nonionic iodinated contrast agent was slowly injected. Fluoroscopy was used to observe the deceleration of flow and stagnation. Control renal angiograms were performed just after embolization. After the procedure, the animals were observed for 1 day and then sacrificed with intravenous sodium thiopental. The technical success was observed in seven of the seven animals.. After embolization procedure, none of the animals died or experienced a major systemic adverse event. On macroscopic examination of the embolized kidneys, thrombus at the level of main renal artery formed after Ankaferd embolization was more compact compared with the thrombi that was not Ankaferd-associated, which was observed elsewhere. Microscopically, majority of the renal tubular cells (80-90 %) were necrotic, and there was epithelial cell damage in a small portion of the cells (10-20 %). RAE was safe and effective in the short-term with Ankaferd in studied animals. Further studies should be conducted to better delineate the embolizing potential of this novel hemostatic agent.

Endovascular Treatment of Renal Artery Bifurcation Stenoses with Branched Balloon Angioplasty

An 85-year-old man with left sided single kidney presented with end-stage renal failure after an acute intestinal bleeding. A complex bifurcational stenoses distally to a 6 months previously implanted ostial stent in the left renal artery was found on duplex imaging and angiogram. These two de-novo stenoses in the distal main renal artery and the proximal segment of the lower branch were simultaneously treated with a ultra-low profile, monorail bifurcation balloon catheter system (Avion Bifurcation RX2™, Invatec, Italy) that consists of a main vessel balloon (20/3.5 mm) and a side vessel balloon (20/2.75 mm). One day and three months postinterventionally, duplex ultrasound demonstrated no recurrent stenoses. Bifurcation balloon catheter systems for complex renal artery stenosis are discussed.

Renal artery stent revascularization with embolic protection in patients with ischemic nephropathy

A prospective analysis of renal artery stent revascularization with distal embolic protection in a high-risk patient population with ischemic nephropathy is presented. A total of 63 patients (median age 70.2 years, range 54-86 years) had significant atherosclerotic stenosis of 83 renal arteries documented on pre-procedural imaging. All patients had baseline chronic renal insufficiency with a documented deterioration in renal function in the 6 months before revascularization. The endovascular technique used in all patients involved primary passage of an embolic filter into the distal main renal artery followed by primary stent deployment with a balloon expandable stainless steel stent. The filter baskets were recaptured and contents submitted for pathological analysis. At 6 months post-intervention, 97% of patients demonstrated stabilization or improvement in renal function. Only 3% of patients had an inexorable decline in renal function, unchanged by the intervention. After a mean follow up of 16.0 months (6-27), 94% of patients demonstrated stabilization or improvement in renal function. One patient suffered an acute post-procedural deterioration in renal function. In total, 60% of the filter baskets contained embolic material. This study confirms the technical feasibility of renal artery stent deployment with adjuvant embolic protection. The excellent results for renal preservation at 6 months post-intervention also suggest that a distal embolic protection device may improve the impact of percutaneous renal revascularization on progressive deterioration in renal function. The postulated mechanism is through the prevention of atheromatous embolization and the embolic yield from the distal filters supports this hypothesis. Patients most likely to receive the greatest benefit are those with mild baseline chronic renal insufficiency and a recent decline in renal function.

Assessment of 100 Live Potential Renal Donors for Laparoscopic Nephrectomy with Multi–Detector Row Helical CT

To retrospectively review the authors' experience with multi-detector row helical computed tomography (CT) in assessing 100 consecutive live potential renal donors. Hospital ethical committee approval was obtained; informed patient consent was not required. One hundred potential renal donors underwent multi-detector row CT assessment. Nonenhanced, arterial phase, and nephrographic phase examinations were performed. Delayed topograms were acquired to visualize the collecting system anatomy. A vascular radiologist prospectively interpreted the multi-detector row CT images. A second vascular radiologist, blinded to the initial results, retrospectively reviewed the images. Eighty candidates subsequently underwent donor nephrectomy, including 70 laparoscopic donor nephrectomies (LDNs) and 10 open donor nephrectomies (ODNs). Surgical findings served as the reference standard for 80 kidneys. The imaging findings in all 100 candidates (200 kidneys) were reviewed, although these findings were considered observational data only because there was no reference standard for 120 kidneys. Multi-detector row CT findings predicted uncomplicated LDN in 67 of 70 patients. Small upper-pole capsular arteries arising from the distal main renal artery in two patients were not described in the multi-detector row CT report: In one patient, the arising vessels resulted in conversion to ODN because of bleeding; in the other patient, arterial reconstruction was performed. In another patient, conversion to ODN was necessary because of ongoing bleeding from an avulsed large lumbar venous tributary to the left renal vein. Observational data revealed that multiple renal arteries--most of which were accessory renal arteries--were seen in 52 (26%) kidneys. Early branching of the main renal artery was seen in 24 (12%) kidneys, and main renal arterial abnormalities were identified in six (3%). Capsular arteries were detected in 10 (5%) kidneys. Major variations in the anatomy of the main renal veins--including multiple right renal veins, a retroaortic left renal vein, and a circumaortic left renal vein--were seen in 28 (14%) kidneys. Large (>5 mm in diameter) systemic tributaries to the left renal vein were seen in 25 (25%) kidneys. There was no significant interobserver disagreement between the vascular radiologists. Multi-detector row CT findings can predict successful LDN in live potential renal donors.

Renal angioplasty and stenting with distal protection of the main renal artery in ischemic nephropathy: early experience.

We present a retrospective review of a single tertiary hospital experience in renal artery stent revascularization with distal protection in patients with ischemic nephropathy. The objectives of the study included preliminary assessment of the effect of distal protection on procedure-related acute deterioration in renal function and on renal salvage. All patients had significant atherosclerotic main renal artery stenosis, documented at preprocedural imaging, and a degree of chronic renal impairment before revascularization. Forty-six renal arteries were treated in 37 patients with preprocedural renal impairment, which was mild in 10 patients, moderate in 19 patients, and severe in 8 patients. Median patient age was 72 years (range, 59-85 years). All patients underwent primary stenting of renal artery ostial stenoses with adjuvant use of a filter device (Angioguard guide wire system; Cordis Corp, Division of Johnson & Johnson, Miami, Fla) in the distal main renal artery. The filter baskets were recaptured for pathologic analysis. Overall, in 95% of patients, including all patients with preprocedural mild or moderate renal impairment, renal function was stabilized or improved after revascularization. In 5% of patients decline in renal function was unchanged. No patients had acute postprocedural deterioration. Mean follow-up was 12.5 months (range, 2-28 months). These results are better than in most reports in the literature and also better than in a historical group of similar patients with ischemic nephropathy who underwent stent revascularization without distal protection at the same institution. The improved results are thought to be due to prevention of cholesterol atheroembolization during the procedure by the distal filter baskets. Sixty-five percent of the distal protection baskets contained embolic material, including fresh thrombus, chronic thrombus, atheromatous fragments, and cholesterol clefts. A distal protection device may significantly improve results during stent revascularization. There are a number of unique demands on a renal protection device, and the ideal device has not yet been developed.

Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound.

The objective of this study was to determine the quantitative intravascular ultrasound (IVUS) and angiographic changes that occur during 1 year follow-up after renal artery stent placement, given that restenosis continues to be a limitation of renal artery stent placement. 38 consecutive patients with symptomatic renal artery stenosis treated with Palmaz stent placement were studied prospectively. IVUS and angiography were performed at the time of stent placement and at 1 year follow-up. At follow-up, angiographic restenosis was seen in 14% of patients. The lumen area in the stent, seen with IVUS, was significantly decreased from 24+/-5.6 mm(2) to 17+/-5.6 mm(2) (p<0.001) solely due to plaque accumulation. The distal main renal artery showed a significant decrease in lumen area owing to a significant vessel area decrease from 39+/-14.0 mm(2) to 29+/-9.3 mm(2) (p<0.001) without plaque accumulation. Angiographic analysis confirmed this reduction in luminal diameter and showed that the distal renal artery diameter at follow-up was significantly smaller than before stent placement (86+/-23.0% vs 104+/-23.9% of the contralateral renal artery diameter; p=0.003). Besides plaque accumulation in the stent, unexplained shrinkage of the distal main renal artery was evidenced with IVUS and angiography 1 year following stent placement.

Ipsilateral atherosclerotic and fibromuscular renal artery stenosis

A 71-year-old lady was referred with drug-resistant hypertension. Aortography demonstrated diffuse aortic disease with significant atheromatous stenoses involving both proximal renal arteries. Selective injection on the right side showed typical appearances of fibromuscular dysplasia (FMD) in the distal main renal artery. The proximal stenosis was stented to 6 mm. Subsequently, it was discovered that she had been diagnosed with FMD 33 years previously.

Renal Doppler, Renal Artery Stenosis, and Renovascular Hypertension

There are two methods of duplex evaluation for renal artery stenosis (RAS): (a) direct interrogation of the main renal artery and (b) indirect duplex evaluation of the distal renal arterial tree (distal main renal artery, segmental or interlobar branches of the renal artery). Direct and indirect methods have comparable sensitivity (low 90% range) and specificity (mid-90% range) for detection of ≥ 60% RAS. Direct interrogation requires that the entire length of both renal arteries be evaluated and is plagued by a relatively high technical failure or incomplete examination rate, long examination times, and difficulties in measuring accurate velocities due to suboptimal angles of incidence. Indirect evaluation, on the other hand, is technically successful in the vast majority of cases and less time consuming than direct interrogation. We recommend the indirect method for initial evaluation, but direct interrogation whenever the indirect evaluation is equivocal or abnormal. Although less demanding than direct methods, indirect duplex methods still require a thorough understanding of Doppler principles and meticulous technique. Direct interrogation criteria for ≥ 60% RAS are (a) renal artcry-to-aortic ratio (RAR) of ≥ 3.5 or (b) peak systolic velocity (PSV) ≥ 180 cm/s in association with poststenotic turbulence. Indirect parameters to diagnose ≥ 60% diameter RAS include acceleration time (AT) <.07 s, acceleration index (Al)<2.78 kHz/s2/MHz, acceleration (ACC)<3 m/s2, absence of the normal early systolic peak (ESP), difference in resistivity index between the ipsilateral and contralateral kidney (RID) <—5, and marked asymmetry in the shape of waveforms between the right and left kidneys or between upper-h mid-, and lower portions of one kidney. We found pattern recognition for loss of ESP the most expedient and sensitive parameter for 60% diameter RAS (91% sensitivity. 96% specificity). Limitations of indirect Doppler methods include insensitivity for 50% diameter RAS, inability to distinguish severe stenosis from occlusion, and insensitivity for stenosis in an accessory or segmental renal artery. In addition, bilateral indirect Doppler abnormalities may be due to occlusive disease proximal to the renal arteries (i.e., aortic coarctation) rather than bilateral RAS. Duplex sonography is useful to assess the effectiveness of revascularization procedures, [percutaneous transluminal angioplasty (PTA). stent placement, surgical graft placement]. After successful revascularization, indirect Doppler parameters return to normal immediately. Their failure to return to normal indicates a poor technical result and also predicts a poor blood pressure response to treatment. Patients with indirect Doppler abnormalities have higher systolic and diastolic blood pressures than subgroups of hypertensive patients who have a ≥ 10% of RAS based on clinical selection criteria.

Changes in Renal Artery Doppler Indexes Following Renal Angioplasty

Doppler indexes were measured in 14 renal arteries in 13 patients before and after percutaneous transluminal angioplasty to determine if changes in these parameters occurred after the procedure. Angioplasty was technically and clinically successful in 12 cases, and adequate Doppler signals were obtained from 13 of 14 arteries. The pulsatility index, resistive index, and acceleration of the distal main renal artery Doppler waveform increased significantly after angioplasty, while the time to systolic peak and the renal-aortic ratio remained unchanged. The former may be useful noninvasive indexes to screen patients for restenosis of the renal artery before it becomes clinically evident. A long-term follow-up study is needed to test this hypothesis.

Extracorporeal renal artery reconstruction for renovascular hypertension

Extracorporeal reconstruction can be applied to the successful repair of stenoses in the distal renal artery and its hilar branches. This study evaluates the short- and long-term results of extracorporeal renal artery reconstruction in 65 patients, including 5 children, with renovascular hypertension who were treated from 1974 through 1989. The mean age of the patients was 37 years (range, 7 to 67 years). The cause of the stenoses was arteriosclerosis in 8 patients, fibrodysplasia in 54 patients, and miscellaneous in 3. Hypertension was severe before treatment with a mean blood pressure of 187147 mm Hg that was reduced to a mean of 159102 mm Hg after medical therapy. Ten patients had renal dysfunction. Results were evaluated both at short-term intervals (mean, 7.9 months; 64 patients) and long-term intervals (mean, 5.9 years; 60 patients), after surgery. Blood pressure responses were classified as beneficial (cured/improved) or failures. Anatomic results were evaluated by angiography in 98% of the patients at the short-term interval and in 77% of the patients at the long-term interval. Extracorporeal renal artery surgery was performed on 78 kidneys among 65 patients (unilateral, 45 patients; bilateral, 13 patients; unilateral extracorporeal and contralateral in situ, 7 patients). In most of the cases autologous arterial graft was used for reconstruction. Early in the series one patient died as a result of the operative procedure (165, 1.5%). A beneficial blood pressure response occurred in 53 patients (5365; 82%) at the short-term interval and in 49 patients (4961; 80%) at the long-term interval, with the average blood pressure at the short-term interval being 13885 mm Hg and at the long-term interval being 13985 mm Hg. Renal function improved in all patients with preoperative renal dysfunction. Graft stenosis or occlusion of the main renal artery was neither observed at the short-term interval nor at the long-term interval. However, residual stenoses were observed in 9 of the 163 reconstructed distal branches (5.5%). Extracorporeal renal artery reconstruction with autologous arterial grafts can be effectively applied to lesions of the distal main renal artery and its hilar branches with durable functional results.

Extracorporeal renal artery reconstruction for renovascular hypertension

Extracorporeal reconstruction can be applied to the successful repair of stenoses in the distal renal artery and its hilar branches. This study evaluates the short- and long-term results of extracorporeal renal artery reconstruction in 65 patients, including 5 children, with renovascular hypertension who were treated from 1974 through 1989. The mean age of the patients was 37 years (range, 7 to 67 years). The cause of the stenoses was arteriosclerosis in 8 patients, fibrodysplasia in 54 patients, and miscellaneous in 3. Hypertension was severe before treatment with a mean blood pressure of 187/147 mm Hg that was reduced to a mean of 159/102 mm Hg after medical therapy. Ten patients had renal dysfunction. Results were evaluated both at short-term intervals (mean, 7.9 months; 64 patients) and long-term intervals (mean, 5.9 years; 60 patients), after surgery. Blood pressure responses were classified as beneficial (cured/improved) or failures. Anatomic results were evaluated by angiography in 98% of the patients at the short-term interval and in 77% of the patients at the long-term interval. Extracorporeal renal artery surgery was performed on 78 kidneys among 65 patients (unilateral, 45 patients; bilateral, 13 patients; unilateral extracorporeal and contralateral in situ, 7 patients). In most of the cases autologous arterial graft was used for reconstruction. Early in the series one patient died as a result of the operative procedure (1/65, 1.5%). A beneficial blood pressure response occurred in 53 patients (53/65; 82%) at the short-term interval and in 49 patients (49/61; 80%) at the long-term interval, with the average blood pressure at the short-term interval being 138/85 mm Hg and at the long-term interval being 139/85 mm Hg. Renal function improved in all patients with preoperative renal dysfunction. Graft stenosis or occlusion of the main renal artery was neither observed at the short-term interval nor at the long-term interval. However, residual stenoses were observed in 9 of the 163 reconstructed distal branches (5.5%). Extracorporeal renal artery reconstruction with autologous arterial grafts can be effectively applied to lesions of the distal main renal artery and its hilar branches with durable functional results.

Percutaneous transluminal angioplasty for pediatric renovascular hypertension.

Five children had percutaneous transluminal angioplasty (PTA) for renal artery stenosis, involving the mid- or distal main renal artery or proximal branches in 4 and developing after saphenous vein patch angioplasty in 1. All 5 children became normotensive following the procedure, but one later became hypertensive due to recurrent renal artery stenosis. The authors recommend PTA for treatment of mid- to distal renal artery stenosis in children.

Renovascular Hypertension Secondary to Arterial Fibrodysplasia

RENOVASCULAR hypertension is most commonly caused by atherosclerosis, and the proximal renal artery is usually involved in this process. Approximately 40% of renal hypertension is secondary to fibromuscular hyperplasia.¹This disease process primarily affects the distal main renal artery, but in approximately 24% of the cases, the primary and secondary branches of the renal artery are involved.¹In these latter situations, the disease is not amenable to the usual surgical procedure of bypass vein grafting. We recently cared for a 49-year-old woman with renovascular hypertension secondary to fibromuscular disease. This patient's problem was successfully treated by renal artery dilation using a No. 4 Fogarty balloon. <h3>Report of a Case</h3> A 49-year-old woman had long-standing hypertension. Her blood pressure (BP) was poorly controlled with hydrazaline hydrochloride, methyldopa, and methyclothiazide. She had noted the onset of severe headaches that required medication. A recent intravenous pyelogram (IVP) showed a differentiation in