Long-term results after surgical reconstruction for renal artery fibromuscular dysplasia

Risks and benefits of renal artery stenting in fibromuscular dysplasia: Lessons from the ARCADIA-POL study

INTRODUCTION

Although renal stenting is the standard revascularization method for atherosclerotic renal artery stenosis (RAS) (FMD-RAS), stenting in fibromuscular dysplasia (FMD) RAS is usually limited to periprocedural complications of angioplasty and primary arterial dissection. The main aim of the study was to retrospectively analyze the immediate and long-term results of renal stenting versus angioplasty in patients with FMD.

METHODS

Of 343 patients in the ARCADIA-POL registry, 58 patients underwent percutaneous treatment due to FMD-RAS (in 70 arteries). Percutaneous transluminal renal angioplasty (PTRA) was performed as an initial treatment in 61 arteries (PTRA-group), whereas primary stenting was undertaken in nine arteries (stent-group). Stent-related complications were defined as: in-stent restenosis > 50% (ISR); stent fracture; under-expansion; or migration.

RESULTS

In the PTRA-group, the initial restenosis rate was 50.8%. A second procedure was then performed in 22 arteries: re-PTRA (12 arteries) or stenting (10 arteries). The incidence of recurrent restenosis after re-PTRA was 41.7%. Complications occurred in seven of 10 (70%) arteries secondarily treated by stenting: two with under-expansion and five with ISR. In the stent-group, stent under-expansion occurred in one case (11.1%) and ISR in three of nine stents (33.3%). In combined analysis of stented arteries, either primarily or secondarily, stent-related complications occurred in 11/19 stenting procedures (57.9%): three due to under-expansion and eight due to ISRs. Finally, despite several revascularization attempts, four of 19 (21%) stented arteries were totally occluded and one was significantly stenosed at follow-up imaging.

CONCLUSION

Our study indicates that renal stenting in FMD-RAS may carry a high risk of late complications, including stent occlusion. Further observational data from large-scale registries are required.

Surgical revascularization of bilateral renal artery stenosis due to fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a noninflammatory disease affecting small- and medium-sized arteries of the renal and the carotids. It affects the renal arteries in nearly 60%–75% cases. The primary clinical manifestation of renal FMD is hypertension. Medial fibroplasia represents the most common dysplastic lesion. We report two cases who presented with hypertension and renal insufficiency and on evaluation was found to have bilateral renal artery stenosis. Stenting of the renal vessels was not possible due to the narrowed caliber of the vessel and inability to cannulate the renal arteries. They underwent renal artery revascularization with a splenorenal end to end anastomosis. The renal parameters and blood pressure of both the patients stabilized subsequently. Renal revascularization can be a good option for patient having failed angioplasty with stenting.

Optimal management of renal artery fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory angiopathy of unknown cause affecting medium-sized (most commonly renal) arteries and causing renovascular hypertension. The most common medial multifocal type of FMD (with the “string of beads” appearance) is more than four times more prevalent in females than in males. FMD accounts for up to 10% of cases of renovascular hypertension. Compared with patients with atherosclerotic renal artery stenosis, patients with FMD are younger, have fewer risk factors for atherosclerosis, and a lower occurrence of atherosclerosis in other vessels. The etiology is multifactorial, including vessel wall ischemia and smoking, as well as hormonal and genetic factors. Intra-arterial digital subtraction angiography is still the gold standard for exclusion or confirmation of renal artery stenosis caused by FMD, at least in young patients, who more often have lesions in branches of the renal artery. For FMD patients with atherosclerosis and those who are older (>50–55 years), significant renal artery stenosis may be confirmed or excluded with ultrasonography. The FMD lesion is typically truncal or distal, whereas atherosclerotic lesions are more often proximal or ostial. Treatment options are medical, endovascular (percutaneous transluminal renal angioplasty [PTRA]), and surgical. Invasive treatment should be considered when hypertension cannot be controlled with antihypertensive drugs and in patients with impaired renal function or ischemic nephropathy. PTRA has become the treatment of choice and normally yields good results, especially in unifocal disease and young patients. Pressure gradients are normally completely abolished, and there is no indication for stent placement. Surgical revascularization is indicated after PTRA complications; thrombosis, perforation, progressive dissection, repeated PTRA failure or restenosis. Centralization of handling is recommended.

Efficacy of renal revascularization in a patient with fibromuscular renal artery stenosis and heart failure

We report the case of a 65-year-old woman with a solitary kidney who developed hypertension due to renal artery stenosis caused by fibromuscular dysplasia. In addition, an echocardiogram revealed severe left ventricular systolic and diastolic dysfunction. Despite antihypertensive drug treatment that included diuretics, her serum concentration of brain natriuretic peptide was persistently elevated and associated with progressive worsening of renal function. She underwent iliac artery to renal artery bypass grafting. After the surgery, blood pressure control was good, the serum concentration of brain natriuretic peptide decreased, and left ventricular diastolic function improved. This case exemplifies the efficacy of renal revascularization in patients with fibromuscular renal artery stenosis and heart failure.

[Fibromuscular dysplasia]

Fibromuscular dysplasia is an idiopathic, segmental, nonatherosclerotic and noninflammatory disease of the muscle layer of arterial walls that leads to stenosis of small- and medium-sized arteries. Fibromuscular dysplasia preferentially affects young women. Although it can affect every arterial tree, it most often touches the renal and internal carotid arteries. Renal fibromuscular dysplasia can cause hypertension by stenosis of the renal artery, most often seen on angiography as resembling a "pearl necklace". Cerebrovascular fibromuscular dysplasia becomes symptomatic when the arterial stenosis is tight and causes hypoperfusion, embolism, or thrombosis or when arterial dissection or rupture of the associated aneurysm occurs.

Fibromuscular Dysplasia: An Uncommon Cause of Secondary Hypertension

Fibromuscular dysplasia is a noninflammatory vascular disease that commonly affects the distal two thirds of the renal artery and branch vessels, but occasionally involves other arteries. Progression of stenosis occurs in 16%-38% of renal arteries. Although the etiology is unknown, genetic studies suggest a relationship to the angiotensin-converting enzyme I allele. Thin, young Caucasian women without a family history of hypertension are most commonly affected. An abdominal or flank systolic-diastolic bruit is an important clue for the diagnosis. Most noninvasive screening tests are not sensitive or reproducible to be used to rule out renal artery stenosis, but digital subtraction renal angiography usually confirms the diagnosis. Percutaneous renal artery angioplasty is the treatment of choice, but may not result in normalization of blood pressure if diagnosis is delayed. Since restenosis occurs, continued follow-up is necessary.

Surgical Management of Renal Fibromuscular Dysplasia: Challenges in the Endovascular Era

Percutaneous transluminal renal angioplasty (PTRA) is the primary treatment for renal fibromuscular dysplasia (RFMD). Surgical revascularization is limited to patients who fail or are unsuitable for PTRA. All patients who were operated on with RFMD since the indications for renal PTRA were expanded in our institution were retrospectively reviewed. Outcome included patency, hypertension, and renal function. Twenty-six patients had reconstruction of 32 renal arteries between 1998 and 2004. The mean age was 47.1 +/- 14 years; the majority (81%) were female. Six patients had bilateral disease and three had a solitary kidney. Operations were done for hypertension in 25 patients, renal artery aneurysm in 8, and chronic dissection in 1, alone or in combination. Six patients had a failed PTRA and 20 were unsuitable for it. Aortorenal bypass was done most often (n = 28) and saphenous vein was the preferred conduit (n = 25). The distal anastomosis was to the main renal artery in 13 patients and to the branch arteries in 19. Ex vivo repair was needed in five patients. Five intraoperative revisions were done because of abnormalities on duplex scan. One patient died unexpectedly 42 days after operation from myocardial infarction. Extrarenal complications occurred in five patients. Median follow-up was 2.4 (range, 42 days to 6.3) years and was available in all but one patient (96%). Two bypasses occluded at 3 and 376 days, which resulted in loss of the kidneys. One graft stenosis was treated successfully with PTRA at 239 days. All failures occurred in men. One-year cumulative primary patency was 89 +/- 8% and was not adversely affected by prior PTRA or complex repair. Hypertension at 1 year was cured in 27% of the patients and improved in 60%. No patient developed acute or chronic renal failure. Surgical reconstruction for RFMD has excellent short-term patency. Failed PTRA or complex reconstructions did not adversely affect outcome.

Fibromuscular dysplasia

The most common clinical manifestations of fibromuscular dysplasia (FMD) are hypertension due to renal artery involvement and transient ischemic attack or stroke due to carotid or vertebral artery involvement. Patients with renal artery FMD and hypertension should undergo primary angioplasty with the goal of curing the hypertension. If the blood pressure fails to normalize following angioplasty, the physician should institute antihypertensive medications according to the recommendations of the Joint National Committee on the Prevention, Detection, and Treatment of High Blood Pressure VII. In patients with cerebrovascular FMD, antiplatelet agents represent the cornerstone of therapy. Percutaneous angioplasty has emerged as the preferred treatment for symptomatic cerebrovascular FMD.

Renal revascularization in Takayasu arteritis–induced renal artery stenosis

PURPOSE

This study was undertaken to define the long-term effects of renal revascularization on blood pressure, and renal and cardiac function in patients with Takayasu arteritis-induced renal artery stenosis (TARAS).

METHODS

Twenty-seven patients (25 women; mean age, 27 years) with TARAS underwent intervention. Primary, primary assisted, and secondary patency rates were determined, and the late effects on blood pressure, renal and cardiac function, and survival were analyzed.

RESULTS

All patients had hypertension (mean blood pressure, 167/99 mm Hg; 2.5 antihypertensive medications per patient). Mean estimated glomerular filtration rate in patients not receiving hemodialysis was 76 mL/min, and in five patients serum creatinine concentration was greater than 1.5 mg/dL. Three patients were hemodialysis-dependent, and two had intractable congestive heart failure. Forty interventions were performed, including 32 aortorenal bypass procedures, two repeat implantations, four nephrectomies, and two transluminal angioplasty procedures. Postoperative morbidity was 19%. There were no deaths. During follow-up (mean, 68 months), three graft stenoses, all due to intimal hyperplasia, and three graft occlusions occurred. Two of three graft stenoses were successfully revised. At 1, 3, and 5 years of follow-up, primary patency was 87%, 79%, and 79%, respectively; primary assisted patency was 93%, 89%, 89%, respectively; and secondary patency was 93%, 89%, and 89%, respectively. Intervention resulted in a decrease in blood pressure to a mean of 132/79 mm Hg (P<.0001), and the need for antihypertensive medications was reduced to one per patient (P<.01). Mean glomerular filtration rate increased to 88 mL/min (P<.005), and two patients no longer required hemodialysis. Congestive heart failure resolved in both patients, and did not recur. There were three deaths during follow-up, with 5-year and 10-year actuarial survival of 96% and 80%, respectively.

CONCLUSIONS

Renal revascularization to treat TARAS is durable, has a salutary effect on blood pressure, and enhances long-term renal and cardiac function. This response establishes renal revascularization as a successful and durable intervention for TARAS, and a benchmark to which other therapies should be compared.

Percutaneous Transluminal Renal Angioplasty (PTRA) and Surgical Revascularisation in Renovascular Disease—A Retrospective Comparison of Results, Complications, and Mortality

OBJECTIVE

To evaluate results, complications and mortality following percutaneous transluminal renal angioplasty (PTRA) and open surgical revascularisation for renovascular disease.

METHODS

A retrospective evaluation of 381 renovascular patients (median age 64, range 9-99 years, 152 women) treated at Malmö University Hospital during 1987-1996. Two hundred and sixty-two (69%) of the patients were treated with PTRA, 106 (28%) with open revascularisation.

RESULTS

Thirty-day mortality was 2% in the PTRA group and 9% after open surgery (p<0.001). There were no differences between groups concerning the number of re-do procedures, but first re-do was performed after seven (IQR 3-14) months in the PTRA group, and after 15 (IQR 10-44) months after open revascularisation (p<0.0001). After a median follow-up of 4 months (IQR 0-13) systolic and diastolic blood pressure (BP) had decreased (p<0.0001) in both groups. The number of antihypertensive drugs was reduced (p<0.0001) and S-creatinine levels were unchanged in both groups. Long-time survival assessed with log-rank analysis was better (p<0.01) in the PTRA group. The risk ratio for death with open revascularisation was 1.69 (p<0.01).

CONCLUSIONS

In this retrospective comparison, PTRA was as effective as open revascularisation, with lower complication rate and lower early and long-time mortality, but with shorter time to first re-do.

Surgical treatment of renal artery dissection in 25 patients: indications and results

OBJECTIVE

Results of surgical revascularization in 25 patients with renal artery dissection (RAD) over 14 years, with mean follow-up of 55.3 months (range, 10-111 months), were analyzed. Indications for surgery were renovascular hypertension and preservation or improvement of kidney function.

PATIENTS AND METHODS

Two patients (both 20 years of age) underwent emergency surgery after severe trauma; 23 patients (mean age, 41 years) underwent elective surgery in a chronic stage of disease. Preoperative, postoperative, and follow-up examinations included duplex ultrasound scanning, determination of serum creatinine and urea concentrations, and evaluation of blood pressure control. All long-term patients underwent digital subtraction angiography preoperatively and postoperatively. All histologic specimens of resected renal arteries were re-evaluated by two independent pathologists.

RESULTS

Histologic re-evaluation confirmed the traumatic origin in 2 patients who underwent emergency surgery and 1 who underwent elective surgery. Renal artery dissection developed spontaneously, with no histologic signs of trauma or fibromuscular dysplasia, in 22 patients. In 17 revascularized kidneys (61%) a kidney infarction had already developed preoperatively, and the kidneys were diminished in size or function. Results of revascularization and improvement of hypertension depended on preoperative extent of renal infarction. Hypertension resolved or improved in 86% of patients without preoperative kidney damage, but in only 38% with preoperatively damaged kidneys. Kidney function was preserved in 23 of 28 revascularized kidneys (82%). During follow-up, late renal artery occlusion developed in 3 kidneys.

CONCLUSIONS

Renal artery dissection can be effectively treated with surgical revascularization. Primary nephrectomy should be considered only in patients with a large ischemic kidney infarction, with significant deterioration of kidney function, to effectively cure or improve severe renovascular hypertension.