Clinical Effect of Endovascular Treatment on Blood Pressure and Kidney Function for Hypertensive Patients with Renal Artery Stenosis

The objective of this study was to evaluate the clinical effect of endovascular treatment on postoperative blood pressure (BP) control and kidney function of hypertensive patients with renal artery stenosis (RAS). Between January 2004 and December 2011, RAS was diagnosed in 120 renal arteries from 115 hypertensive patients. Preoperative and postoperative BPs and glomerular filtration rate (GFR) were monitored. Postoperative oral antiplatelet and antihypertensive agents were administered. Clinical follow-up was available for all patients for at least 6 months. Balloon angioplasty was performed successfully in 110 patients, and stents were deployed in 94 renal arteries from 89 patients. Hypertension was cured and lessened in 19 and 61 patients, respectively. Blood pressure was stable and worsened in 26 and 9 patients, respectively. The renal function was improved and stable in 23 patients and 57 patients, respectively. Deterioration of renal function was observed in 11 patients. Doppler ultrasound after discharge revealed 87 patent renal arteries and fixed stents in 82 patients 6 months after procedure. Balloon angioplasty and stent deployment are effective and feasible procedures for patients with RAS that help in controlling BP and improving renal function moderately.     

Renal Vein Immunoreactive Renin in Patients with Renal Artery Stenosis and Essential Hypertension

In 36 patients with unilateral renal artery stenosis and in 24 with essential hypertension the plasma levels of total immunoreactive renin, and enzymatically active renin were measured in both renal veins (V) and in the aorta (A) by direct RIA by using monoclonal renin antibodies. Active renin and trypsin-activatable inactive renin were also measured by indirect RIA with angiotensin-I antibodies. The V/A ratio for the different forms of renin calculated from the results of direct and indirect RIA were not different. The V/A ratio of active renin for the kidney with the stenotic artery was 3.04 ± 0.28 (mean ± sem) with direct and 3.02 ± 0.25 with indirect RIA. The contralateral ratio was 1.04 ± 0.02 with the direct and 1.05 ± 0.02 with the indirect RIA. In essential hypertension it was 1.28 ± 0.04 with direct RIA and 1.28 ± 0.04 with indirect RIA.

Chronic treatment with captopril had no influence on this ratio in both patients groups. The V/A ratio of total immunoreactive renin was lower than that of active renin and this ratio had lost discriminative power for lateralization. This ratio was significantly greater than one on the affected side in renal artery stenosis but not contra laterally and in essential hypertension. This study shows that renin activity after trypsin-activation of plasma is an accurate measure of the total renin concentration, i.e. active renin plus prorenin. It also shows that a kidney with a stenotic artary secretes inactive renin, which is immunologically related to active renin and is likely to be prorenin.

Direct RIA for measuring active renin is technically more simple than indirect RIA. Direct RIA however is somewhat less sensitive. For measuring the V/A ratio for active renin in patients with renal artery stenosis this can be overcome by stimulating the renin-angiotensin system for instance by captopril.     

Case Report: Bilateral Renal Artery Stenosis in a 7-Year-Old Child

We present a 7-year-old child with uncontrolled hypertension caused by bilateral renal artery stenosis. He underwent renal angioplasty on both sides. While the right side showed successful dilatation, the left side was unsuccessful, leaving a near total occlusion. Due to the lack of satisfactory control of his blood pressure, he was scheduled for an iliorenal bypass. Following surgery, all antihypertensive medications were withdrawn. Computed tomography angiography performed 18 months after surgery showed patent angioplasty on the right side and patent bypass on the left side. Both endovascular and open surgical treatments are feasible options with good results in this age group.     

中老年病人肾动脉开口部狭窄检出率及结果分析

目的了解中老年住院病人中肾动脉狭窄(RAS)患病情况及其危险因素,探讨肾动脉影像检查的重要性。方法以心内科同期住院病人存在高血压或顽固性高血压、冠心病/疑似冠心病和颈动脉狭窄的病人共247例为入选对象,对其中197例病人冠状动脉造影(CAG)后行选择性肾动脉造影(RAG),另50例病人行磁共振(MRA)检查,分析RAS病人与非RAS病人的临床特点。结果检出肾动脉开口部狭窄程度≥50%的病人40例,87.5%病人缺乏特异临床表现,RAS局部血管杂音发生率低。其中42.5%患有顽固性高血压,35.0%伴有冠心病,57.5%的病人住院B超检查有颈动脉狭窄,RAS的发病随年龄增高而增加。结论同非RAS的病人相比,RAS病人在高血压、冠心病、高龄,特别是颈动脉狭窄人群中的比例高。肾动脉造影和/或MRA,可提高肾动脉狭窄的检出率。     

肾动脉狭窄的治疗现状

肾动脉狭窄与进行性缺血性肾衰竭和高血压相关的心血管疾病的发病率和死亡率有着密切关系。对于此类患者的治疗现在并无确定方法。现比较各种治疗的临床研究结果。内科药物治疗是各种治疗的基础,而且仍有进一步研究的空间。目前的资料显示腔内治疗相比外科和单纯内科治疗有一定的优势,但一些特殊的病例,外科治疗仍然是很好的选择。介入治疗中一些新技术,如肾动脉远端保护装置及药物涂层支架在临床应用已有尝试,但仍处于探索阶段。目前仍需大样本多中心随机对照试验来进一步明确证明介入治疗的作用。     

Impact of Renal Artery Stent Implantation on Hypertension in Patients with Hemodialysis

The benefit from renal artery stent implantation to treat atherosclerotic renal artery stenosis (ARAS) is not well understood in hemodialysis patients. We sought to evaluate the effects of renal artery stenting on hypertension of hemodialysis patients. Renal artery stent implantation was successfully performed on eight hypertensive hemodialysis patients with ARAS (mean ± SD, 66 ± 10 years; men 6, women 2). Blood pressure was measured by automated oscillometric recordings just before hemodialysis. Mean values of the blood pressure, measured 12 times a month, were used for blood pressure analysis. Values of systolic blood pressure decreased at 6 months after renal artery stent implantation (162.6 ± 29.7 to 121.1 ± 23.3 mm Hg, p = 0.0015). Values of diastolic blood pressure also decreased from 77.6 ± 13.6 to 65.6 ± 7.2 mm Hg (p = 0.02). Renal artery stent implantation for ARAS had a beneficial effect on hypertension in hemodialysis patients.     

Use of Renin-Angiotensin Inhibitors in People with Renal Artery Stenosis

Background and objectives

People with atherosclerotic renal artery stenosis may benefit from renin-angiotensin inhibitors, angiotensin-converting enzyme inhibitors, and angiotensin-receptor blockers, but little is known about the factors associated with their use.

Design, setting, participants, & measurements

The Cardiovascular Outcomes in Renal Atherosclerotic Lesions study (ClinicalTrials.gov identified: {"type":"clinical-trial","attrs":{"text":"NCT00081731","term_id":"NCT00081731"}}NCT00081731) is a prospective, international, multicenter clinical trial that randomly assigned participants with atherosclerotic renal artery stenosis who received optimal medical therapy to stenting versus no stenting from May 2005 through January 2010. At baseline, medication information was available from 853 of 931 randomly assigned participants. Kidney function was measured by serum creatinine–based eGFR at a core laboratory.

Results

Before randomization, renin-angiotensin inhibitors were used in 419 (49%) of the 853 participants. Renin-angiotensin inhibitor use was lower in those with CKD (eGFR<60 ml/min per 1.73 m²) (58% versus 68%; P=0.004) and higher in individuals with diabetes (41% versus 27%; P<0.001). Presence of bilateral renal artery stenosis or congestive heart failure was not associated with renin-angiotensin inhibitor use. Although therapy with renin-angiotensin inhibitors varied by study site, differences in rates of use were not related to the characteristics of the site participants. Participants receiving a renin-angiotensin inhibitor had lower systolic BP (mean±SD, 148±23 versus 152±23 mmHg; P=0.003) and more often had BP at goal (30% versus 22%; P=0.01).

Conclusions

Kidney function and diabetes were associated with renin-angiotensin inhibitor use. However, these or other clinical characteristics did not explain variability among study sites. Patients with renal artery stenosis who received renin-angiotensin inhibitor treatment had lower BP and were more likely to be at treatment goal.     

冠状动脉病变与肾动脉粥样硬化性狭窄

目的探讨动脉粥样硬化性肾动脉狭窄(ARAS)与脉压及其他相关因素的关系。方法553例入选病例在冠脉造影后行非选择性肾动脉造影,应用多变量Logistic回归分析评价脉压及其他临床因素和ARAS的关系。结果连续3年入选553例患者,24例(4.3%)有轻度肾血管病变(腔径狭窄<50%),84例(15.2%)ARAS(腔径狭窄≥50%),冠心病者ARAS(22.6%vs2.0%)及肾血管病变(5.9%vs1.5%)发生率明显高于非冠心病者。多因素Logistic逐步回归分析显示冠脉狭窄程度、脉压、血肌酐是ARAS发生的独立危险因素。结论ARAS与冠心病冠脉病变程度密切相关。脉压和血肌酐升高是ARAS的独立危险因素。     

支架置放术治疗18例肾动脉狭窄

目的　评估支架置放术治疗肾动脉狭窄 (RAS)的疗效与安全性。方法　对 1 8例 ( 1 9例次 )伴有高血压或肾功能不全的RAS≥5 0 %患者 (动脉粥样硬化 7例 ,大动脉炎 4例 ,纤维肌性结构不良 8例次 )进行肾动脉支架置放术 (PTRAS) ,采用门诊方式随访 3～ 41个月 (平均 1 4 5个月 ) ,观察手术对患者血压、肾功能的影响。结果　技术成功率为 1 0 0 % ,未发生并发症 ;术后第 2天疗效 :治愈 6例 ,改善 1 3例次 ;3个月疗效 :治愈 6例 ,改善 1 1例次 ,无效 2例 ;≥ 1 2个月疗效 :共 1 2例 ,治愈 3例 ,改善 9例。结论　RAS≥ 5 0 %者用PTRAS治疗安全、有效 ,对纤维肌性结构不良及大动脉炎患者的疗效较动脉粥样硬化患者好。     

肾动脉介入治疗对肾血管性高血压病人并冠心病的影响

目的探讨肾动脉介入治疗对冠心病预后的影响。方法冠心病合并高血压患者47例经肾动脉造影显示单侧肾动脉狭窄(管腔狭窄≥50%),分为两组,肾动脉介入术组25例和药物治疗组22例。所有患者均未行冠脉血运重建术。测定所有病例治疗前及介入组治疗后的双侧肾静脉及下腔静脉的肾素活性、血管紧张素Ⅱ(AngⅡ)和醛固酮(Ald)浓度的变化。并对病人的血压、心功能、心绞痛发作次数进行半年随访。结果两组患者狭窄侧肾静脉肾素活性明显高于对侧{介入组[狭窄侧:(3.7±0.5)比对侧:(2.1±0.4)]nmol/L.h;药物组[狭窄侧:(3.9±3.1)比对侧:(2.0±1.9)]nmol/L.h,P均<0.01},AngⅡ、Ald亦高于对侧。介入治疗后肾素活性明显降低,与术前比差异有统计学意义{[术后:(2.0±0.7)比术前:(3.7±0.5)]nmol/L.h,P<0.05},术后左室射血分数改善{[术后:(52.5±5.6)比术前:(47.5±5.2)]%,P<0.05},心绞痛发作缓解,从每周(13.2±0.2)次减至(4.6±1.1)次(P<0.05)。结论肾动脉介入治疗能缓解冠心病患者的心绞痛,改善充血性心力衰竭等症状。     

Role of Angiotensin II in the Hypertension Induced by Renal Artery Stenosis

Identical degrees of renal artery stenosis were induced in 5 dogs on two separate occasions; once during continuous inhibition of angiotensin I converting enzyme with enalapril, and once with the dogs untreated. Arterial pressure rose about 25 mm Hg during 3 days of stenosis in untreated dogs, due to increased total peripheral resistance. When the dogs were treated with enalapril, blood pressure had risen 14.5 ± 3.4 mm Hg 24 hours after stenosis due to a 35% increase in cardiac output while total peripheral resistance fell by 16%. By the third day, blood pressure had returned to pre-stenosis levels, cardiac output was close to normal and total peripheral resistance had increased. The stenosis on the renal artery increased the resistance to blood flow of the kidneys in both untreated and enalapril treated dogs. This increase in kidney resistance in the untreated dogs accounted for about 30% of the change in total peripheral resistance. In the enalapril treated dogs, the increased kidney resistance helped offset the vasodilatation in the rest of the vasculature. These results suggest that angiotensin II mediated vasoconstriction of nonrenal vascular beds was responsible for about ? of the hypertension following renal artery stenosis, and the resistance of the stenosis responsible for about ?.     

Diagnosing Renal Artery Stenosis: A Comparison Between Conventional Renography, Captopril Renography and Ultrasound Doppler in a Large Consecutive Series of Patients with Arterial Hypertension

The purpose of the study was to compare the positive and negative predictive values of conventional renography (Reno-A), captopril renography (Reno-B) and ultrasound Doppler (UD) with regard to the diagnosis renal artery stenosis. These three tests, and in addition a renal angiography, were performed in consecutively admitted patients with arterial hypertension, owing to either suspicion of renovascular hypertension or refractoriness to treatment. Patients with occlusion of a renal artery or a serum creatinine level higher than 300 μmol/1, or a previous investigation for renovascular hypertension at another hospital, were excluded from the analysis. The European Multicenter Study (EMS) criteria and local criteria for abnormal renography were compared. Of 131 patients, 28 had a renal artery stenosis (RAS) exceeding 50% reduction in diameter of the artery and 19 exceeding 70%. Using the EMS criteria for renography the predictive values of a negative test for a RAS more than 50% were 0.88 for Reno-A, 0.90 for Reno-B, 0.86 for changes from Reno-A to Reno-B, 0.92 for abnormalities either in Reno-A, Reno-B or changes from Reno-A to Reno-B, and 0.91 for UD. The corresponding values for a RAS more than 70% were 0.94, 0.97, 0.93, 0.98 and 0.96, respectively. The predictive values of a positive test were clearly lower, ranging from 0.20 to 0.75, but best when changes from Reno-A to Reno-B were used, 0.69-0.75. Using local criteria for renography the predictive values of a negative test were almost equal to those obtained by using the EMS criteria, but the predictive values of a positive test were slightly lower. It is concluded that conventional renography, captopril renography and ultrasound Doppler all are very good screening tests for renal artery stenosis, but the positive predictive values are clearly highest when using changes from conventional renography to captopril renogrdphy. It is suggested that captopril renography always should be performed when conventional renography is abnormal and vice versa to obtain the highest positive predictive value, on the assumption that total renal function is normal or almost normal, and that renal function is not absent in the affected kidney.     

冠心病伴肾动脉狭窄的患病率及相关因素研究

目的探讨冠心病患者中肾动脉狭窄(ARAS)的患病率及其相关因素。方法228例冠脉造影患者同时行选择性双肾动脉造影检查,对临床资料和ARAS之间的关系进行单因素和多因素Logistic回归分析。结果228例患者中,ARAS患病率为19.7%;经冠脉造影证实的152例冠心病患者中,ARAS患病率为27.6%;51例冠心病合并颈动脉粥样斑块的患者中,ARAS患病率为49.0%。45例ARAS患者中,左肾动脉狭窄的患病率显著高于右肾动脉(P<0.05)。单因素分析表明,年龄、糖尿病、肾功能不全、颈动脉粥样斑块、冠心病是ARAS的预测因素。多元Logistic回归分析表明,仅年龄、颈动脉粥样斑块、冠脉三支病变是ARAS的独立预测因素。结论对于冠心病患者,尤其是年龄≥60岁及合并颈动脉粥样斑块的患者,冠脉造影后应常规行肾动脉造影,以便早期发现ARAS。     

Contrast-Enhanced Doppler Ultrasound of Renal Artery Stenosis

Over the past few years, there has been extensive research for a reliable, noninvasive, and nonionizing imaging method to screen for renal artery stenosis (RAS). Doppler ultrasound (US) is one of many modalities that have been evaluated for the detection of RAS. The lack of standardization in examination protocols and diagnostic criteria, as well as the wide differences in reported accuracy among different laboratories, however, have prevented universal acceptance of this technique as a reliable screening test for RAS. Recently, the introduction of US contrast agents has substantially expanded the potentials of color Doppler US. The use of microbubble echo enhancers in combination with harmonic Doppler imaging has been shown to improve diagnostic confidence by improving the operator's ability to visualize the renal arteries, and to significantly reduce the number of equivocal examinations. In addition, contrast-enhanced harmonic Doppler US can currently provide objective functional assessment of RAS through analysis of time-intensity renal enhancement curve. State-of-the-art contrast-enhanced Doppler US seems to have the potential to become a useful screening test for patients at risk from renovascular hypertension and a tool for follow-up of patients who undergo revascularization procedures.     

高血压合并肾动脉狭窄患者肾动脉支架术对血压的影响

目的评估肾动脉支架术对高血压合并肾动脉狭窄患者血压的影响。方法对患有高血压的67例肾动脉明显狭窄(管腔内径减少≥70%)的患者行肾动脉支架植入术(PTRAS),术后行血压及血肌酐(SCr)的长期随访。结果患者67例植入77枚支架均获成功。所有患者均随访血压及肾功能,平均随访时间(18±6)月,随访患者的收缩压由(171±23)下降至(160±20)mmHg,P<0.05,舒张压由(95±14)下降至(85±13)mmHg,P<0.01;降压药物的种类显著减少[由(2.7±1.6)下降至(1.9±1.4)种,P<0.01]。术前肾功能正常者(SCr<130μmol/L)术后血压下降最为显著[收缩压由(176±33)下降至(159±26)mmHg,P<0.01,舒张压由(98±15)下降至(83±15)mmHg,P<0.01]。而术前肾功能受损者(130≤SCr≤350μmol/L)术后血压无明显改变。术后随访血肌酐及肾小球滤过率较术前无明显改变。结论肾动脉支架植入术有助于肾功能正常的高血压患者血压控制。     

冠状动脉造影患者中肾动脉狭窄及其相关因素分析

目的探讨冠状动脉造影患者中肾动脉狭窄(RAS)的发生率及其预测因素。方法对235例接受选择性冠状动脉造影的患者同时行选择性肾动脉造影。结果235例患者中,RAS发生率为19.1%;134例冠状动脉狭窄程度≥50%的患者中,RAS的发生率为32.1%;101例冠状动脉狭窄程度<50%的患者中,RAS的发生率为2.0%;经单变量和多变量Logistic回归分析,RAS的独立预测因素是冠脉病变的严重程度、Scr≥115μmol/L和主动脉瓣钙化。结论冠状动脉造影中冠状动脉狭窄程度≥50%的患者RAS的发生率高,尤其是多支冠脉病变、合并主动脉瓣钙化和/或血肌酐≥115μmol/L的患者。     

比较开搏通与氯沙坦在同位素肾显像中诊断肾动脉狭窄的作用

目的　比较开搏通肾显像和氯沙坦肾显像诊断肾动脉狭窄的作用。病例和方法　 2 0 0 0年 10月至 2 0 0 1年 12月 ,共 4 6例疑诊肾血管性高血压的住院患者 ,先行开搏通肾同位素显像 ,2 4小时后行氯沙坦同位素肾显像。所有可疑肾动脉狭窄患者在肾显像后 7天内行肾动脉造影。结果　肾动脉造影显示共 92个肾脏中 6 7个肾脏的肾动脉无明显狭窄 ,另 2 5个肾脏的肾动脉直径狭窄≥ 5 0 %。开搏通肾显像和氯沙坦肾显像诊断肾动脉狭窄的敏感性分别为6 0 0 %和 84 0 % ,特异性分别为 95 5 %和 97 0 % ,准确性分别为 85 8%和 93 4 %。后者诊断的敏感性和准确性显著高于前者 (P <0 0 5 )。结论　氯沙坦肾显像诊断肾动脉狭窄的敏感性和准确性明显高于开搏通肾显像。     

Percutaneous Transluminal Dilatation of Posttransplant Renal Artery Stenosis: Beneficial Effects in Two Cases at High Surgical Risk

Two clinical cases are described in which percutaneous transluminal dilatation (PTD) determined the correction of hypertension and renal hypoperfusion due to renal artery stenosis of the transplanted kidney.     

Treatment of Neurofibromatosis Associated Renal Artery Stenosis with Hypertension by Percutaneous Transluminal Angioplasty

A 12 year old girl with severe arterial hypertension was found to have neurofibromatosis associated bilateral stenoses of the main renal arteries and elevated plasma renin activity in the right main renal vein. Antihypertensive treatment was unable to normalize blood pressure. PTA of the right renal artery from a left axillary approach resulted in normalization of blood pressure and peripheral plasma renin activity. PTA seems to be an effective and safe method for treatment even of complicated forms of renal artery stenosis.