Effect of captopril on blood pressure and renal function in patients with transplant renal artery stenosis

We evaluated 9 patients with transplant renal artery stenosis. Captopril treatment always resulted in a dramatic decrease in renal function. Moreover, only in patients (n = 2) with a stenosis in one out of more renal arteries a satisfying fall in blood pressure was achieved. Surgical reconstruction of the stenosis was successful in 4 out of 5 patients. Angiotensin I-converting enzyme inhibition in transplant renal artery stenosis often leads to loss of graft function, probably due to efferent vasodilation.     

Fibromuscular hyperplasia as a cause of transplant renal artery stenosis

SUMMARY:   There are several causes of transplant renal artery stenosis, resulting in hyperten- sion and renal dysfunction. Rarely, fibromuscular hyperplasia may cause such a presentation, and this case report discusses the historical, diagnostic and management issues pertaining to this rare situation.     

A correlation between direct and indirect Doppler ultrasonographic measures in transplant renal artery stenosis

Screening for transplant renal artery stenosis (TRAS) with Doppler ultrasonography (DUS) is increasingly used in the era of kidney transplantation. Direct Doppler study of the stenotic site is a time- consuming and difficult method that requires an angle of interrogation parallel to the vessel. The aim of this study was to assess the correlation between the direct-PSVs (peak systolic velocity at the stenotic site), PSVs/PSVi (PSVi, peak systolic velocity of the adjacent iliac artery)-and indirect-intrarenal arterial resistive index (RI), perfusion index (PI), acceleration time (AT)-DUS findings in the kidney transplant recipients with TRAS. We performed 26 DUS studies of both intrarenal and main renal arteries in 19 TRAS patients (who had PSVs > 150 cm/s, PSVs/PSVi > 2). The mean values of PSVs and PSVs/PSVi were 212 +/- 44.19 cm/s and 2.77 +/- 0.77, respectively. The mean intrarenal RI, PI, and AT were 0.48 +/- 0.065, 0.70 +/- 0.12, and 177.8 +/- 54.6 msec, respectively. A significant negative correlation was found between PSVs and intrarenal RI (Pearson correlation coefficient (r) = -0.4, two-tailed P = .043). No correlation was found between intrarenal PI or AT and the direct DUS findings (P > .05). With a cutoff level of 0.55 for intrarenal resistive index, the sensitivity of this parameter to detect proximal renal arterial stenosis was about 85%. Conclusively, PSVs and intrarenal RI were negatively correlated. Intrarenal resistive index can be used as an screening measure for detection of TRAS.     

Prevention of transplant renal artery stenosis.

Transplant renal artery stenosis occurred in 17 of 142 consecutive transplants (12 percent). All stenoses were in the renal artery distal to the anastomosis and two separate forms are recognized: angulation and segmental stenosis. Successful surgical correction in 12 of 17 patients relieved the hypertension and resulted in improved renal function. No patients receiving dipyridamole, a drug which inhibits platelet aggregation and intravascular fibrin deposition, developed segmental renal artery stenosis. No other factors could be identified which were important in either causing or preventing renal artery stenosis. Since intrarenal vascular changes are an integral aspect of rejection, the protection afforded by dipyridamole against segmental renal artery stenosis indicates that segmental stenosis is probably a manifestation of rejection.     

移植肾动脉血流峰值速度加快与移植肾动脉狭窄相关性研究

目的:探讨肾移植术后半年内移植肾动脉血流峰值速度加快与移植肾动脉狭窄相关性。方法:回顾性分析我院102例肾移植患者术后半年内移植肾多普勒超声图像检查结果及临床资料,比较患者收缩期血流峰值速度(PSV)、血压及移植肾功能。结果:102例患者中,有27例患者出现较高的PSV,其中4例患者呈现持续性PSV升高,经行移植肾动脉造影检查而确诊为移植肾动脉狭窄(TRAS),行经皮肾动脉支架植入术(PTRAS)后,PSV降至正常,血压恢复正常,随访6~13个月未见狭窄复发。结论:在肾移植术后半年内,移植肾动脉PSV加快未必是肾动脉狭窄,可先随访观察,若超声提示PSV呈持续性升高,尤其是伴顽固性高血压,则需行移植肾动脉造影明确是否是TRAS。PTRAS是TRAS安全有效的治疗方法。     

Angiographic evaluation and treatment of transplant renal artery stenosis

Transplant renal artery stenosis is an uncommon but important complication of renal transplantation. It is a potentially reversible cause of patient morbidity and allograft dysfunction, which can present both early and late in the post-transplant period. Although transplant renal artery stenosis can be detected using noninvasive imaging, definitive diagnosis and percutaneous treatment typically require the use of invasive angiographic techniques. In experienced hands, these studies can be performed safely, effectively and with a low risk of contrast induced nephrotoxicity when alternative contrast agents are used.     

Percutaneous transluminal angioplasty for transplant renal artery stenosis in children

Severe hypertension developed secondary to renal artery stenosis in 11 of 229 children who received a renal allograft. Renal artery stenosis was suspected because of de novo development of hypertension or exacerbation of pre-existing hypertension, which was detected 1 to 24 months after transplantation. Selective renal angiography was performed 2 to 74 months after transplantation (mean 13 months). Follow-up was 1 to 8 years (mean 2.5 years). The stenosis involved the anastomosis in 5 patients and was distal to the anastomosis in 6. One graft had an arteriovenous malformation. Seven grafts were suitable for vessel dilation; percutaneous transluminal angioplasty was partially successful in 4 cases in which the stenosis occurred at the anastomosis. The remaining patients were treated with medical therapy alone and the grafts were not lost. Our findings suggest that strictures distal to the anastomosis rarely are amenable to percutaneous transluminal angioplasty and should be treated medically whenever possible. Strictures at the anastomosis respond to vessel dilation but antihypertensive medication also often is required. An operation should be reserved for patients who do not respond to these measures.     

彩色多普勒超声诊断肾动脉瘤

目的探讨彩色多普勒超声诊断肾动脉瘤的价值。方法回顾性分析经CTA或手术证实的5例肾动脉瘤超声表现,评价病变大小、边界、位置、内部回声及血流特点。结果 4例经超声检查获得准确定位及诊断,1例误诊为胰尾囊肿;灰阶超声显示动脉局限性扩张呈球形或梭形,内部均匀无回声,其中1例瘤壁附着血栓,呈低回声;CDFI显示瘤体内部血流为涡流;PWD显示瘤体内部为动脉血流频谱。结论肾动脉瘤超声表现具有特征性,灰阶超声结合CDFI及PWD对于诊断肾动脉瘤具有重要价值。     

移植肾动脉狭窄的诊断与治疗

目的　探讨移植肾动脉狭窄 (TRAS)的诊断与治疗方法。　方法　对 8例TRAS患者的临床表现、辅助检查及治疗情况进行回顾性分析并结合文献复习。　结果　 8例经彩超检查 ,5例明确诊断为TRAS ,3例提示移植肾动脉可疑狭窄 ,诊断TRAS的特异性为 78% ,阳性预测值为6 2 %。 7例行经皮穿刺移植肾动脉球囊扩张成形术 (PTRA) ,均获得近期临床治愈 ,随访 3～ 12个月 ,血Cr 186 .2～ 12 1.3μmol/L ;1例切除移植肾。　结论　肾移植术后出现不明原因高血压、突发性尿量减少和血Cr升高应考虑是否有移植肾动脉狭窄。彩超检查可作为筛选及随访手段 ,PTRA可作为TRAS的首选治疗方法。     

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.