Embolic control of hypertension caused by segmental renal artery stenosis.

Renovascular hypertension was controlled in a 15-year-old boy by total infarction of the renal parenchyma behind a segmental renal artery stenosis. Two separate embolizations were required to occlude the branches distal to the stenosis. Blood pressure did not return to normal until after the second procedure. This approach may be useful in patients with intrarenal arterial stenoses who would be difficult to approach operatively without sacrificing a significant portion of the kidney.     

Renal transplant artery stenosis and percutaneous transluminal angioplasty

Ten patients with renal transplant artery stenosis were treated with percutaneous transluminal angioplasty (PTA). All patients suffered from hypertension refractory to drug treatment. PTA was successful in five patients. Blood pressure improved significantly and the antihypertensive medication could be reduced or withdrawn. Acute angulation at the anastomosis prevented successful PTA in four patients. One inaccessible stenosis was corrected surgically. No significant complications arose. If a renal transplant artery stenosis is haemodynamically significant, PTA should be considered the method of first choice for correction.     

Renal artery stenosis in en-bloc pediatric renal transplant: demonstration by captopril-enhanced renal scintigraphy.

A double-pediatric kidney transplant recipient, who developed hypertension, was found to have unilateral renal artery stenosis. The stenosis was successfully assessed by single-dose 99mTc-diethylenetriaminepentaacetic acid renal scintigraphy, confirmed by renal arteriography, and treated by percutaneous transluminal angioplasty. This case illustrates the usefulness of Captopril-enhanced renography in screening en-bloc transplant patients suspected for renal vascular hypertension.     

Renal artery stenosis in children

In a large paediatric renal unit over the last 14 years, 19 children (10 male and 9 female, aged 1 week to 16 years, mean 7 years) with renal artery stenosis (RAS) were evaluated. Transplant RAS cases were not included. All 19 children were hypertensive. In 10 this was an incidental finding. Based on clinical findings and arteriography, the causes of RAS included a middle aortic syndrome (MAS) (n = 5), neurofibromatosis (n = 3), William's syndrome (n = 3), fibromuscular hyperplasia (FMH) (n = 4), idiopathic RAS (n = 2) and isolated branch artery stenosis (n = 2). Previous studies have suggested FMH is the commonest cause of RAS in the paediatric population. In our study the largest subgroup are MAS/William's syndrome children, in whom the angiographic appearances were indistinguishable. Where possible, management, both surgical and radiological, and eventual outcomes have been described.     

The diagnosis of segmental transplant renal artery stenosis by captopril renography.

The captopril renogram test has been shown to be a sensitive test for the diagnosis of renal artery stenosis in native and transplanted kidneys. Most reports have involved only stenosis of the main renal artery. Although segmental renal artery stenosis has been diagnosed successfully in native kidneys, it is not clear whether the captopril renogram test can diagnose segmental renal artery stenosis in a transplanted kidney. The authors report two cases of successful identification, by the captopril renogram test, of functionally significant stenosis in an intrarenal branch of a single transplant renal artery.     

Percutaneous transluminal angioplasty for transplant renal artery stenosis.

A recent report has challenged the efficacy and safety of percutaneous transluminal angioplasty (PTA) for the treatment of transplant renal artery stenosis (TRAS). From January 1983 to December 1990, 24 PTA procedures were performed for TRAS in 18 patients. The stenoses were anastomotic in two cases, in the main renal artery in 14, and segmental in eight. After PTA, the residual stenosis was less than 20% in 14 (58%), 20%-50% in four (17%), and greater than 50% in six (25%). The mean diastolic blood pressure decreased from 106 mm Hg 1 day prior to PTA to 82 mm Hg 1 day after PTA. Long-term follow-up mean diastolic blood pressure (at 2-32 months) was 93 mm Hg (P less than .01). Eleven of the 18 patients (63%) had a 10% or greater reduction in diastolic blood pressure on long-term follow-up. Major complications occurred in two patients; one groin hematoma required surgical evacuation, and one polar infarct led to hypertension that was difficult to control. No surgical revisions of the transplant renal artery were necessary. The authors' data indicate that PTA should remain the treatment of choice for nonanastomotic TRAS.     

Renal artery stenosis caused by nonspecific arteritis (Takayasu disease): results of treatment with percutaneous transluminal angioplasty.

Renovascular hypertension is common in nonspecific aortoarteritis (Takayasu disease). The utility of percutaneous transluminal renal angioplasty in managing this disease has been reported infrequently, and technical problems in using this treatment method have not been described. We retrospectively evaluated the results of renal angioplasty in treating 33 stenoses in 20 patients. Each patient's diagnosis was based on the criteria established by the Aortitis Syndrome Research Committee of Japan. Criteria for selection of patients for angioplasty were (1) severe hypertension uncontrolled by single-drug therapy, (2) angiographic evidence of at least 70% stenosis of the renal artery with a pressure gradient of more than 20 mm Hg, and (3) a normal sedimentation rate. The transfemoral route was used to treat all 33 stenoses. Follow-up examinations included blood pressure and medication evaluation 1 day, 1 week, and 4-6 weeks after treatment, and thereafter at 6-month intervals. Technical success was obtained in 28 lesions (85%) in 17 patients (85%). All failures occurred in the presence of coexistent abdominal aortic disease and tight, proximal stenosis of the renal artery. Technical difficulties were attributed to the tough, noncompliant nature of the stenoses, which were difficult to cross and resisted repeated, prolonged balloon inflations. These patients experienced backache and a fall in systemic blood pressure during balloon inflation. In one patient, the ipsilateral renal vein was injured during angioplasty and required surgery. Clinical success was obtained in 14 (82%) of the 17 patients in whom technical success was achieved and included cure in six patients and improvement in eight others. Follow-up 1-18 months (mean, 8 months) after treatment showed restenosis in six (21%) of 28 lesions. We conclude that renal angioplasty in nonspecific arteritis is associated with technical difficulties; however, the short-term results are good and the complication rate is acceptable.     

Hemodynamic significance of iliac artery stenosis: pressure measurements during angiography.

Peak systolic pressure gradients were obtained before and after vasodilatation in 42 patients (50 limbs) with arteriographic iliac artery stenosis of questionable significance. Patients were divided into three groups according to per cent narrowing of the iliac artery. Pressure gradients across the site of stenosis tended to be significant in patients with greater than 75% stenosis (greater than or equal to 20 mm Hg) but not in patients with less than 50% stenosis; patients in the middle group (50-75% stenosis) demonstrated a wide variance. Thus the arteriogram is not an accurate indicator of hemodynamically significant lesions, particularly in patients with 50-75% stenosis where pressure measurements are of greatest value. Variations in the aortic and femoral artery systolic peak pressure occurred following vasodilatation, indicating the importance of simultaneous pressure recording.     

Renal transplant arterial stenosis: percutaneous transluminal angioplasty

Seven hypertensive patients underwent percutaneous transluminal angioplasty for relief of arterial stenosis complicating renal allotransplantation. Five had end-to-side anastomosis of the donor renal artery to the recipient external iliac artery, and two had end-to-end anastomosis of the donor renal artery to the recipient internal iliac artery. Each patient had developed hypertension (blood pressure greater than 145/95 mm Hg), elevated peripheral venous plasma renin, and six demonstrated decrease in renal function as detected by an increase in serum creatinine at least 2 months after transplantation and without evidence of rejection. Angioplasty was technically successful without significant complications and blood pressure and biochemical abnormalities were improved or stabilized in all seven patients.     

Unilateral renal artery stenosis and hypertension. I. Angiography

The preoperative angiographic findings in 43 patients with unilateral renal artery stenosis or occlusion were reviewed in order to record abnormalities such as diameter of stenosis, collateral circulation, poststenotic dilatation and reduction of kidney size. The significance of the various lesions is discussed.     

介入治疗移植肾动脉狭窄

目的探讨移植肾动脉狭窄(TRAS)的介入治疗。方法21例TRAS患者从肾移植到出现肾动脉狭窄症状平均6．6个月(3～15个月)，记录经皮血管成形术(PTA)前后血压变化和肌酐水平。经对侧股动脉或左肱动脉入路，使用普通球囊导管(5F，直径4～6mm，长度20～30mm)和微球囊导管(2．6F，直径3mm，长度36mm)分别对21例TRAS行PTA术，其中5例放置支架。结果21例TRAS患者共行32次PTA(行1次PTA13例，2次5例，3次3例)，其中22次经对侧股动脉，10次经左肱动脉穿刺插管。PTA治疗前肾动脉狭窄率为79％～97％，PTA后狭窄率降为10％～30％。PTA前收缩压150～210mmHg(1mmHg=0．133kPa)，平均170mmHg，舒张压90～145mmHg，平均120mmHg；PTA后收缩压降为100～190mmHg，平均135mmHg，舒张压降为80～125mmHg，平均85mmHg。首次PTA后再狭窄率38％，再次PTA后狭窄率14％。32次PTA共使用普通球囊导管25个，微球囊导管7个。5个支架4个为自膨式支架，1个为球囊扩张式。术后随访3～60个月(平均23个月)。21例中最终治愈6例，改善8例，好转5例，无效2例。除1例肱动脉入路发生术后穿刺点血肿外无其他并发症。结论TRAS的PTA治疗安全有效，配合肱动脉入路和微球囊导管有助于提高手术成功率；合理选用支架能降低再狭窄率。     

Renal artery stenosis: duplex Doppler evaluation

The renal arteries of 40 patients without renal or renovascular disease were examined with duplex real-time Doppler sonography. Special views were employed to obtain adequate images and Doppler recordings from the renal arteries. Time limits were placed on the duration of the examination, the better to reflect common clinical practice. Velocity spectral analysis of the Doppler shift frequency was achieved in 82.5% of the arteries examined and a characteristic "Doppler signature" for the renal artery identified. This was compared with the Doppler signal from the renal arteries of eight patients with renal artery stenosis. Significant differences in spectral pattern were demonstrated in renal artery stenosis. These differences are illustrated and their potential for screening for renovascular disease in systemic hypertension is discussed.     

Azotemia caused by renal artery stenosis: treatment by percutaneous angioplasty

Percutaneous angioplasty of the renal artery was performed in 79 patients who had stable or climbing serum creatinine levels greater than 1.7 mg/dl and hemodynamically significant stenosis of the renal artery. Patients who had nonrenal causes of azotemia, nephropathy caused by iodinated contrast material, or serum creatinine levels that were declining while the patients were receiving medical therapy before angioplasty were excluded from the study. Angioplasty resulted in a significant (greater than 20%) decline in the level of serum creatinine (average, 2.7 mg/dl before to 1.7 mg/dl after) in 43% of these patients during an average follow-up period of 16 months. A significant decrease in the level of serum creatinine was seen in 61% of patients with bilateral stenosis, 38% of patients with unilateral stenosis with absent contralateral renal blood flow, and 38% of patients with unilateral stenosis and normal contralateral renal blood flow. Recapture of lost nephron function was least successful in patients whose levels of serum creatinine were greater than 4.0 mg/dl (14%); this included one (11%) of nine patients who were already on hemodialysis. We conclude that angioplasty of the renal artery can play a major role in the treatment of patients who have mild azotemia and bilateral stenosis of the renal artery. It is less successful in treatment of patients who have severe azotemia and those who have unilateral disease.     

Diagnosis of common iliac artery thrombosis and renal artery thrombosis in a kidney transplant by radionuclide renography

In a 58-year-old woman, the external iliac artery was accidentally dissected during the arterial anastomosis of a kidney transplant. An immediate CT angiogram showed an almost total occlusion of the common iliac artery. After the transplantation, radionuclide renography with Tc-99m MAG3 showed no flow across the right common iliac artery and no graft vascularization. Sequential images showed a photopenic area corresponding to the renal graft. These findings were interpreted as common iliac artery thrombosis and renal artery thrombosis associated with renal graft infarct. Excision of the transplant and iliofemoral bypass were performed. Pathologic examination of the graft showed massive acute renal infarct and renal artery thrombosis.