Percutaneous transluminal angioplasty treatment of renal transplant artery stenosis

Since June 1979, percutaneous transluminal angioplasty (PTA) has been the procedure of choice for renal transplant artery stenosis (RTAS) at the Hospital of the University of Pennsylvania. Of 241 renal allograft recipients, 17 (7%) when studied by arteriogram because of suspected RTAS proved to have significant stenosis (the mean reduction in luminal width for the group being 68%) and underwent PTA. RTAS was equally prevalent in cadaver and related kidney allografts and was no less common in HLA-identical related donor grafts, arguing against the importance of immune factors in etiology. RTAS was equally prevalent whether the anastomotic technique was end to end or end to side. However, when RTAS occurred after end to side anastomoses, it was usually postanastomotic. Fifteen of 17 of the attempts at dilation by PTA were successful by angiographic analysis. Thirteen of the 15 successfully dilated patients had long-term allograft survival and in all of these instances blood pressure (BP) was decreased after PTA. After a mean of 67 weeks, BP decreased from a systolic of 184 +/- 24 mm Hg pre-PTA to 135 +/- 15 mm Hg (P less than 0.001) and from a diastolic of 115 +/- 10 mm Hg pre-PTA to 87 +/- 11 mm Hg (P less than 0.001). The majority of patients continue to require antihypertensive drugs but in a less vigorous regimen than pre-PTA. Serum creatinine level fell following PTA from 1.9 +/- 0.6 to 1.7 +/- 0.5 mg/100 ml (P less than 0.01). Repeat angiographic study was done in nine patients, an average of 61 weeks after PTA, and no recurrent RTAS was identified. Three minor complications of PTA occurred but none led to long-term sequelae. Thus, we believe PTA of RTAS is relatively safe, carrying less mortality and morbidity than operative treatment, and is capable of improving BP control and renal allograft function.     

经皮血管成形术治疗移植肾动脉狭窄的临床研究

目的 评估经皮血管成形术在治疗移植肾动脉狭窄(TRAS)导致的移植肾功能损害和(或)高血压中的效果.方法 回顾性分析1998年7月至2007年1月经皮肾动脉造影明确诊断为移植肾动脉狭窄的16例患者的临床资料.在16例患者被确诊前先行多普勒超声检查,有13例被发现TRAS,3例阴性,假阴性率为18.75%.对16例TRAS患者均采取经皮血管成形术治疗.术后对患者进行了3年的随访,分别在术后1周、6个月、1年、2年和3年时评估肾功能和高血压改善状况.以平均动脉压较术前下降至少15%定义为高血压改善;以血清肌酐降低至少20%定义为移植肾功能改善.结果 经皮血管成形术成功率100%,16例患者经治疗后均获临床治愈.术后1周、6个月、1年、2年和3年时,肾功能改善率分别为81.25%、68.75%、62.5%、56.25%和50%,高血压改善率分别为62.5%、75%、75%、56.25%和50%,所有患者服用降血压药物的种类和用量均减少.结论 经皮血管成形术对TRAS导致的肾功能损害和高血压有明显的改善作用,是安全和有效的治疗方法 .     

Percutaneous transluminal angioplasty. The procedure of choice in the hypertensive renal allograft recipient with renal artery stenosis

A retrospective review of 547 renal transplants performed over a six-year period revealed allograft renovascular hypertension secondary to RTAS in 39 (7.1%) patients. Percutaneous transluminal angioplasty (PTA) resulted in immediate cure or improvement in 76% of the patients, increasing to 83% in patients with functioning kidneys at a mean follow-up period of 30 months (1-72 months). The renal artery stenosis (RTAS) was equally distributed between living-related and cadaver kidney recipients and did not appear to be more prevalent in end-to-end or end-to-side anastomoses. The blood pressures fell from pre-PTA levels of 167 +/- 22 mmHg systolic to 141 +/- 23.7 post-PTA and 102 +/- 11 mmHg diastolic pre-PTA to 88 +/- 12 mmHg post-PTA (P less than 0.01). Of 25 cured or improved patients, 24 are on significantly less hypertensive medication. Two patients died of causes unrelated to the PTA and only one patient lost a kidney because of the procedure. Compared with operation, PTA is a safer and more effective procedure for the initial treatment of RTAS.     

Long-term clinical results of percutaneous transluminal angioplasty in transplant renal artery stenosis.

Twenty-five patients with transplant artery stenosis were identified among 1141 renal graft recipients. Impaired graft function (9 patients), hypertension (4 patients) or both (12 patients) were the indications for arteriography. All were treated by percutaneous angioplasty (PTA). The immediate technical success rate was 88% and actuarial graft survival was 88% and 80% at 2 and 5 years respectively. The long-term success rate on graft function was 67% (median observation time 24 months) and on hypertension 63% (median observation time 23 months). Six patients needed rePTA (8 procedures) and in only one patient was surgical repair performed. No case of graft loss due to PTA was recorded and in only one case did occlusion of a segmental artery lead to impairment of graft function. Minor complications were recorded in four other cases and in no case was surgical intervention necessary. Based on these results we favour PTA as a first-line interventional procedure in transplant renal artery stenosis, and the need for surgical repair has been low.     

Percutaneous transluminal angioplasty and stent placement for recurrent carotid artery stenosis

OBJECT: Treatment consisting of percutaneous transluminal angioplasty (PTA) and stent placement has recently been proposed as an alternative to surgical reexploration in patients with recurrent carotid artery stenosis following endarterectomy. The authors retrospectively reviewed their experience after performing 25 procedures in 21 patients to assess the safety and efficacy of PTA with or without stent placement for carotid artery restenosis. METHODS: The mean interval between endarterectomy and the endovascular procedures was 57 months (range 8-220 months). Seven arteries in five patients were treated by PTA alone (including bilateral procedures in one patient and repeated angioplasty in the same vessel in another). Early suboptimum results and recurrent stenosis in some of these initial cases prompted the authors to combine PTA with stent placement in the treatment of 18 arteries over the past 3 years. No major periprocedural deficits (neurological or cardiac complications) or death occurred. There was one periprocedural transient neurological event, and in one patient a pseudoaneurysm of the femoral artery (at the access site) required surgical repair. In the 16 patients who each underwent at least 6 months of follow-up review, no neurological events ipsilateral to the treated artery had occurred after a mean follow-up period of 27 months (range 6-57 months). Three of five patients who underwent PTA alone developed significant (>50%) asymptomatic restenoses that required repeated angioplasty in one and PTA with stent placement in two patients. Significant restenosis (55%) was observed in only one of the vessels treated by combined angioplasty and stent placement. CONCLUSIONS: Endovascular PTA and stenting of recurrent carotid artery stenosis is both technically feasible and safe and has a satisfactory midterm patency. This procedure can be considered a viable alternative to surgical reexploration in patients with recurrent carotid artery stenosis.     

Follow-up of renal artery stenosis by duplex ultrasound

We have previously shown that duplex ultrasound is an accurate method of diagnosing renal artery stenosis (93% accuracy compared with angiography in the diagnosis of less than 60% stenosis, 60% to 99% stenosis, or occlusion). With this method we have now serially observed 35 renal arteries with 60% to 99% renal artery stenosis in 27 patients. Nineteen stenotic renal arteries in 15 patients were observed without intervention. There was a significant decrease in kidney size (mean difference - 1.0 cm; p less than 0.01; mean follow-up 13 months) but all 19 renal arteries remained patent. Percutaneous transluminal angioplasty (PTA) was performed in five patients (six renal arteries) for renovascular hypertension. Renal duplex scanning documented relief of renal artery stenosis in two patients whose hypertension improved after PTA and confirmed residual 60% to 99% renal artery stenosis in three patients whose hypertension did not improve after PTA (mean follow-up 6.5 months). Aortorenal bypass was performed for 10 stenotic renal arteries in seven patients. At a mean follow-up of 9 months duplex ultrasound documented eight patent and two occluded aortorenal bypass grafts. Duplex ultrasound is useful both for defining the natural history of untreated renal artery stenosis and assessing the results of renal artery angioplasty or bypass.     

Delayed extensive arterial dissection after percutaneous transluminal angioplasty for transplant renal artery stenosis.

A 26-year-old renal transplant recipient with graft artery stenosis underwent percutaneous transluminal angioplasty (PTA), which was followed by extensive renal artery dissection leading to graft loss. This report reminds one that, although widely considered a safe procedure, PTA is not free of complications.     

Outcome of endovascular intervention for infrainguinal vein graft stenosis

Assisted graft patency rate following revision of a graft stenosis is far better than that following thrombectomy of an occluded graft. Graft revision by endovascular means has been proposed as a suitable alternative to more invasive surgery. This study reports our experience with endovascular treatment of vein graft stenosis. Between December 1992 and September 2000, percutaneous transluminal balloon angioplasty (PTA) was performed on 90 vein graft stenoses in 87 infrainguinal vein bypass grafts identified by routine graft duplex scan (peak systolic velocity, PSV > 300 cm/sec). All 90 stenoses treated by PTA were retrospectively analysed for stenosis-free patency rate (life-table analysis). Re-stenosis was defined by PSV exceeding 300 cm/sec at the same site of the vein graft where a stenosis was dilated.Ninety vein graft stenoses (72 primary stenoses and 18 recurrent stenoses) in 33 femoropopliteal (above knee), 30 femoropopliteal (below knee) and 24 femorotibial vein bypass grafts were treated by PTA. The timing of PTA ranged from one to 252 months (mean, 23.9 months) from the initial surgery. Cumulative stenosis-free patency rate after PTA was 55.8% at 6 months, 54.0% at one year and 45.0% at three years. Stenosis-free patency rate at six months was significantly lower for revision of recurrent stenosis (25.9%) than for primary stenosis (61.6%) (P = 0.01). The revision of duplex scan detected vein graft stenosis with endovascular intervention was associated with an acceptable stenosis-free patency rate. However, recurrent stenosis treated by PTA had a significantly inferior outcome. Direct surgical revision would be more appropriate for recurrent lesions.     

Comparative results of angioplasty and aortofemoral bypass in patients with symptomatic iliac disease

Advantages and limitations of percutaneous transluminal angioplasty (PTA) and aortofemoral bypass (AFB) performed for the treatment of iliac atherosclerosis were retrospectively studied in 61 patients who presented over a four-year period. Technical success was achieved in 92% and symptoms initially relieved in 80% of 25 patients who underwent 31 PTA procedures for iliac stenosis or occlusion. Similarly, 92% (33/36) of patients treated with AFP improved clinically. There were no operative deaths in either group or significant difference in the rate of major complications. During the follow-up period, symptoms recurred in nine PTA patients (36%) due to progressive (five patients) or recurrent (four patients) disease within the iliac vessels. Late failure of AFB (8%) was significantly less frequent. While both PTA and AFB provide satisfactory initial relief of ischemic symptoms due to iliac atherosclerosis, long-term results of PTA are limited by progressive or recurrent disease in the iliac vessels.     

Utility of static pressure ratio recording during angioplasty of arteriovenous graft stenosis

Intra-access static pressure ratio (SPR) (intra-access pressure/mean arterial pressure) can be measured during angioplasty (PTA) to assess the functional importance of an arteriovenous graft (AVG) stenosis. We used SPR in 70 patients with AVGs who underwent 98 angioplasty procedures. SPR was measured during angioplasty by placing a catheter tip at mid-access. Inflow stenosis (IF) = stenosis proximal to the tip of the catheter. Outflow stenosis (OF) = stenosis distal to the tip of the catheter up to the superior vena cava-atrial junction. Post PTA, access flow (Qa) was assessed within 2 weeks. Complete data sets for both SPR and Qa were available in 83 procedures. Using a normal SPR ratio of 0.3-0.4 at mid-graft, three patterns of SPR were noted. In 63 of 83 (76%) cases SPR was elevated prior to PTA (0.71 +/- 0.13 SD). PTA reduced SPR toward normal range (0.44 +/- 0.12) in 53 cases (84%). In the remaining 10 (16%), SPR decreased to a low value (0.22 +/- 0.03) and normalized (0.40 +/- .0.11) only after PTA of a coexisting inflow stenosis. In 12 of 83 (14%) procedures, the initial SPR was low (0.18 +/- 0.04) and increased toward normal (0.3 +/- 0.08) following IF stenosis PTA in seven (58%) cases. For the remaining five (42%) cases SPR increased to a high value (0.70 +/- 0.21) and decreased toward normal range (0.33 +/- 0.07) only after OF stenosis angioplasty. In 8 of 83 (10%) procedures, initial SPR was normal (0.33 +/- 0.02). Angiography revealed coexisting IF and OF stenoses. SPR remained within the normal range after PTA of these lesions (0.33 +/- 0.02). Qa increased significantly in 74 of 83 (89%) procedures (before = 572 +/- 201, after = 1109 +/- 368 ml/min; p < 0.001). SPR measurements can assist in hemodynamic assessment of an AVG during angioplasty procedure.     

Percutaneous angioplasty and stenting of left subclavian artery stenosis in patients with left internal mammary-coronary bypass grafts: clinical experience and long-term follow-up

The authors report their experience with percutaneous transluminal angioplasty (PTA) and stenting of the left subclavian artery (LSA) in patients with recurrent angina and a left internal mammary (LIMA)-coronary bypass graft or in patients who will be undergoing LIMA-coronary artery bypass grafting. From November 1990 to February 2001, 21 patients (11 men and 10 women) with significant left subclavian artery stenosis were treated; 18 patients had a prior LIMA bypass graft, and 3 patients were treated before coronary artery bypass surgery. Angiographic follow-up was performed in 12 patients and clinical follow-up was obtained in all patients. All lesions were atherosclerotic in etiology and located in the proximal left subclavian artery. The mean stenosis was 81% (range 50-100%). All patients initially underwent PTA. Stents were placed in 7 patients for suboptimal PTA results. Technical success was achieved in all patients. Pressure gradient measurements were available in 6 patients. Mean pretreatment gradient was 29 mm Hg (range, 10-50 mm Hg) and fell to 3 mm Hg (0-8 mm Hg) posttreatment. There were 2 minor and 2 major complications. The 30-day mortality rate was 9.5% (2 patients). The remaining 19 patients had clinical or angiographic follow-up of 4-68 months (mean, 27 months). Three patients were found to have recurrent stenoses by angiography 8-43 months after PTA and 3 more had clinical signs of recurrent stenosis. Therefore, the long-term clinical patency rate of LSA PTA and stent was 15 of 19 (79%). One was managed with bypass surgery, 1 with repeat PTA and stent placement, and 1 was managed conservatively. Therefore, the assisted patency was 15 of 19 (79%). Eleven of 19 (58%) of the patients in long-term follow-up had cardiac symptoms, but repeat angiography excluded recurrent LSA stenosis as the cause of their symptoms in 7 cases. Only 4/19 (21%) had cardiac symptoms potentially attributable to LSA restenosis. Four patients expired during follow-up, but 3 had no evidence of subclavian stenosis. PTA and stenting is an effective treatment of proximal left subclavian artery stenosis in patients who develop angina after a LIMA-coronary artery bypass, or in patients before a LIMA-CABG. Cardiac symptoms after LSA PTA and stent are most often due to progressive coronary artery disease rather than to recurrent LSA stenosis.     

Cure and improvement of renovascular hypertension after percutaneous transluminal angioplasty of renal artery stenosis

In the present study we report our long-term experience in 82 patients with renovascular hypertension (48 with atherosclerotic stenosis, 34 with fibromuscular dysplasia) who were followed up for a mean observation period of 23.6 months after percutaneous transluminal angioplasty (PTA) of renal artery stenosis. Our results show a highly significant decrease in mean systolic and diastolic blood pressure. Cure rates were slightly higher in patients with fibromuscular dysplasia (41% cured, 47% improved) than in those with atherosclerosis (23% cured, 54% improved). Kidney function significantly improved in patients with cure, remained stable in those with improvement and worsened in cases classified as unimproved. These results document the good long-term effect of PTA on blood pressure and kidney function in patients with renal artery stenosis.     

Treatment of renal graft artery stenosis. Comparison between surgical bypass and percutaneous transluminal angioplasty

In order to compare saphenous bypass (SB) and percutaneous transluminal angioplasty (PTA) as treatment of renal graft artery stenosis (GAS), we have reviewed the results of both procedures in 33 patients treated consecutively by either SB (n = 16) or PTA (n = 17). All patients had become hypertensive within the first year after transplantation despite triple hypotensive drug therapy. SB was performed 17 (range 3-55) and PTA 19 (range 2-96) months after transplantation. SB failed in only 1 patient as a result of vascular thrombosis with graft loss. PTA was technically unsuccessful in 3 patients and was complicated by vascular branch thrombosis in 1 patient. Blood pressure decrease was similar in both groups: from 179/114 before SB to 147/90 (n = 15, P less than .001) at 6 months and 150/93 (n = 14, P less than .005) at 12 months after SB and from 177/110 before PTA to 149/93 (n = 13, P less than .01) at 6 months and 150/95 (n = 10, P less than .02) at 12 months. At 1 year, control of BP was improved in 85% of SB group patients and 74% of PTA group patients. Recurrent stenosis was documented in 3 PTA group patients: subsequently 1 had a successful SB and the 2 others a repeated PTA--successful in 1, unsuccessful in the other. We conclude that both methods are equally effective for BP control but that PTA entails a higher rate of initial failure and a significant rate of restenosis. However, because of technical ease and better tolerance, PTA emerges as the first-choice treatment of GAS, SB remaining indicated when PTA is not feasible or has failed.     

Cutting balloon angioplasty in hemodialysis arteriovenous fistula stenosis resistant to conventional balloon angioplasty

Objective To investigate the efficacy and safety of cutting balloon angioplasty for the treatment of hemodialysis arteriovenous fistula stenosis resistant to conventional percutaneous transluminal angioplasty (PTA). Methods The patients with arteriovenous fistula stenosis who had suboptimal results (residual stenosis ＞30%) by conventional PTA from December 2011 to February 2015 were enrolled. All the patients received cutting balloon angioplasty were rechecked every three months. Results A total of 25 patients with age of (60.7±12.9) years had suboptimal PTA results. Eleven patients with native arteriovenous fistula (AVF) and 14 patients with graft fistula (AVG) underwent cutting PTA for 30 times. The technical success rate was 86.7% and clinical success rate was 100%. The diameter stenosis pre-procedural and post-procedural of cutting PTA was (1.7±0.6) mm and (4.5±0.8) mm respectively (P＜0.05). Six patients had multiple lesions and the stenosis consisted of 21 outflow venous, 6 graft-to-vein anastomosis, 6 cephalic arch, 2 artery and 1 puncture hole stenosis. The primary access patency at 3 and 6 months for AVF group were 70.0% and 10.0%, while for AVG group the figures were 64.3% and 7.1% (P＞0.05). The secondary access patency at 3 and 6 months for AVF group were 70.0% and 30.0%, while for AVG group the figures were 85.7% and 64.3% (P＞0.05). The follow-up time was (8.1±7.3) months. The restenosis rate was 64.0%. Cutting PTA failed to achieve technical success for four times, of whom 2 patients required graft stent implantation and 2 patients required ultra-high-pressure balloons angioplasty to finally achieve technical success. The median survival time of fistula was 173 days. Conclusions Cutting balloon angioplasty have well short-term patency and safety in arteriovenous fistula stenosis resistant to conventional PTA, especially for calcified lesion or "balloon waist". Although it could provide a satisfied long patency by recurrent PTA, the use of cutting balloon would be not advocated as the first-line treatment for fistula stenosis. The efficacy superiority of cutting balloon between AVF and AVG, as well as the cost-effect comparison between cutting balloon and high-pressure balloon, remains unclear, the verification of which requires large-sampled, prospective and randomized studies.     

Management of Arterial Stenosis Affecting Kidney Graft Perfusion: A Single-Centre Study in 53 Patients

We assessed clinical and duplex sonographic (CDS) findings, and outcome in patients with stenosis of the transplant renal artery (TRAS) or the aorto-iliac segment proximal to the graft (Prox-TRAS) treated with dilatation (PTA), stenting (PTAS) and surgery. From 1988 to 2002, of 1189 patients with renal transplantations, 117 underwent angiography. Fifty-three patients with TRAS (n = 37)/Prox-TRAS (n = 16) were found (4.4%). Clinical presentation included deterioration of hypertension (144 +/- 15/84 +/- 9, 157 +/- 22/90 +/- 10 mmHg; p < 0.001), increase of creatinine (1.7 +/- 0.9, 2.5 +/- 1.3 mg/dL; p = 0.01) and renal failure (n = 12). CDS indicated insufficient perfusion and differentiated between TRAS and Prox-TRAS. From renal transplantation (RTX) until the detection of stenosis pulsatility indices (PI) decreased from 1.2 +/- 0.46 to 0.98 +/- 0.29; (p = 0.001). Fifty-two patients underwent invasive treatment (21 PTA, 10 PTAS and 21 surgery) after which hypertension and creatinine significantly improved. PI increased. Restenosis occurred in 16 (52%) cases of the interventional (PTA 62% and PTAS 30%) and in 3 (14%) of the surgical group (p = 0.011). Hypertension and graft dysfunction due to perfusion problems are rare. Clinical findings are nonspecific but CDS findings are helpful to select patients for angiography. Invasive treatment leads to clinical improvement. Surgery yields better results than PTA, but additional stenting will probably improve the outcome of angioplasty.     

Percutaneous transluminal angioplasty for renovascular hypertension in children

Percutaneous transluminal angioplasty (PTA) has been developed over the past 8 years as an alternative to reconstructive surgery for renovascular hypertension. We report three cases and review the use of PTA in children with renal artery stenosis. At least 37 cases of PTA have been reported in patients whose ages ranged from 1.3 to 17 years (mean 10 years). Of these, 10 had fibromuscular dysplasia; 13 unspecified unilateral renal artery stenosis; 4 bilateral stenosis; 4 neurofibromatosis; 4 renal transplant; 1 atherosclerosis; and 1 postsurgical stenosis. Nine of 10 patients with fibromuscular dysplasia were cured and 3 of 4 with renal transplant arterial stenosis were cured or improved. There were 11 failures of PTA, including all 4 patients with neurofibromatosis and 1 with transplant arterial stenosis. We conclude that PTA is the treatment of choice for children with hypertension due to fibromuscular dysplasia and should be attempted for stenosis of the transplanted renal artery. Other lesions resulting in renal artery stenosis may not be as amenable to dilation and should be considered on an individual basis.R. L. Chevalier is an Established Investigator of the American Heart Association     

The management of renal transplant artery stenosis in children by percutaneous transluminal angioplasty.

Between 1967 and 1989 in this unit 262 children (age at transplantation 9 months to 17 years, mean 9.6 years) had 345 renal transplants performed. Transplant artery stenosis (TAS) was found in 30 (8.7%) as demonstrated by arteriography, performed only when there was unexplained deterioration in transplant function, hypertension that was difficult to control, or in the presence of a vascular bruit. All patients with TAS except one had received a cadaveric allograft. From 1980 onward, percutaneous transluminal angioplasty (PTA) has been available for TAS, and this was attempted on 21 occasions in 16 patients. Nine patients demonstrated angiographic improvement following the procedure, and 7 showed immediate clinical improvement. On one occasion angioplasty precipitated graft loss. Five patients underwent planned corrective surgery, 4 after unsuccessful angioplasties. Our experience suggests that PTA should be the first method of intervention for TAS. Moderate success, both in angiographic and clinical terms, can be achieved, negating the need for surgery, while failure of PTA does not preclude surgical attempts at correction.     

High-grade renal transplant artery stenosis after suboptimal angioplasty: favourable long-term outcome

The purpose of our report is to present the long-term outcomes of three renal transplant recipients with high-grade stenosis and suboptimal percutaneous angioplasty (PTA) because of technical difficulties. Two men and one woman of age 67, 53, and 54 years, who maintained functional cadaveric graft for 17, 9, and 13 years, and had diagnosed significant renal transplant artery stenosis at 2, 1, and 2 years after renal transplantation, respectively, were studied. Stenoses were diagnosed angiographically in the first patient and by Doppler in other two patients, then confirmed by angiography. All three patients had difficult-to-treat hypertension with deterioration of graft function in the presence of or after introducing ACE-inhibitor therapy. PTA was performed in all patients with suboptimal or unsuccessful results as assessed by angiography or control Doppler examination--the residual stenosis was significant and practically unchanged. Surgery was not performed because of high risk, so patients were further treated conservatively. Hypertension was treated avoiding ACE inhibitors. Twelve, 7, and 7 years after angioplasty the serum creatinine is stable in all patients, even decreased compared to pre-PTA and early post-PTA levels, namely, 134, 102, and 75 micromol/L, respectively. Control Doppler examinations revealed a residual stenotic jet in all patients, with slightly decreased peak systolic velocity over time, indicating a slightly decreased grade of stenosis. These observations suggest that renal transplant artery stenosis, even of high grade, can be stable, or even regress with time with excellent long-term graft survival. Randomized studies comparing conservative treatment versus revascularization are warranted.     

Treatment of acute renal artery occlusion after percutaneous transluminal angioplasty

Four patients with occlusive complications after percutaneous transluminal renal artery angioplasty (PTA) have been treated from July 1, 1984, to March 14, 1988. During this interval such renal artery angioplasties were performed in 44 patients. Two resulted in complete main renal artery occlusion, one angioplasty resulted in occlusion of a stenotic renal artery bypass graft, and one renal PTA resulted in segmental branch renal artery narrowing, which was thought to represent a dissection. The latter segmental renal artery narrowing was treated expectantly with good long-term results. One of the main renal artery occlusions was treated by radiologic means by reentry and repeat transluminal dilation. The other two acute complete occlusions, one of an autogenous artery and the other of an aortorenal bypass graft, were treated by aortorenal or ileorenal bypass grafting, respectively. The overall incidence of main renal artery occlusion (including the bypass graft occlusion) after PTA requiring operative intervention was 4.5% (2/44). Revascularization was accomplished after 6 and 8 hours of renal ischemia time for the two surgical procedures. Despite this, the bypass grafts done emergently remain patent, and the involved kidneys appear to be functional. The incidence of main renal artery occlusion after PTA is not as low as would be apparent from a review of the literature. It is proposed that main renal artery occlusion after PTA can be treated successfully by surgical and interventional radiologic techniques because of the presence of protective renal collateral circulation whose formation was stimulated by the renal artery lesion that prompted PTA.     

Transplant renal artery stenosis

A group of 31 patients with transplant renal artery stenoses was identified among 2002 patients undergoing renal transplantation at the University of Minnesota; 29 of the stenoses were at the anastomosis. A total of 43 procedures were performed to correct the stenosis. Angioplasty was performed 25 times, with 3 patients cured and 2 patients improved; 20 procedures resulted in a poor result (3) or a failure (17). The failures were usually due to recurrent stenosis (7 patients) or to arterial injury that resulted in graft loss (4 patients) or successful emergency surgery to save the transplant (3 cases). Surgical repair of the stenosis was performed 18 times. No grafts were lost and 13 patients were cured or improved. These data suggest that angioplasty for anastomotic stenosis yields poor results and that a surgical repair is probably warranted. All 7 patients who had a poor results or failed a technically successful intervention did not have a rise in creatinine secondary to captopril or had a systolic pressure gradient of less than 60 mmHg across the anastomosis. These data also suggest that patients without physiological evidence of renal artery stenosis may not have improvement in their hypertension following repair.