Rinehardt Elena K, Zierler R Eugene, Leverson Glen E
Department of Surgery, University of Wisconsin, Madison, Wisc.
D.E. Strandness, Jr Vascular Laboratory, University of Washington Medical Center and the Department of Surgery, University of Washington, Seattle, Wash.
J Vasc Surg. 2014 Dec;60(6):1593-8. doi: 10.1016/j.jvs.2014.08.109. Epub 2014 Oct 12.
Although common indications for renal duplex scanning (RDS) include hypertension (HT) and renal failure (RF), the role of RDS in the evaluation of patients with RF is not known. The goal of this study was to define ultrasound findings with predictive or discriminatory value in patients with RF and to identify patients undergoing a renal artery intervention as a result of RDS findings.
We conducted a retrospective review of 214 consecutive patients referred to an Intersocietal Accreditation Commission-accredited vascular laboratory for an initial RDS from January 1, 2010, to June 30, 2010. RDS included direct ultrasound evaluation of the main renal vessels and renal parenchyma. Significant renal artery stenosis of ≥ 60% diameter reduction was indicated by a renal/aortic velocity ratio ≥ 3.5 and abnormally increased parenchymal resistance by an end-diastolic ratio ≤ 0.3.
We separated the patients into two groups by indication for RDS: Group I (HT alone, n = 102) and group II (RF alone or with HT, n = 112). When group I was compared with group II, there were significant differences in gender (50% vs 67% male; P = .013), age (50.9 ± 18.5 vs 60.0 ± 14.8 years; P < .001), mean arterial pressure (103.1 ± 18.8 vs 85.7 ± 17.0 mm Hg; P < .001), and creatinine (0.95 ± 0.35 vs 2.25 ± 1.07 mg/dL; P < .001). In group I patients, 86 (84.3%) had normal parenchymal resistance, whereas in group II patients, 68 (60.7%) had abnormally increased parenchymal resistance unilaterally or bilaterally (P < .001). Unilateral or bilateral renal artery stenosis was identified in six group I patients and in three group II patients (P = .315). Evaluation of group II patients revealed a diagnosis of decompensated congestive heart failure (CHF) and the presence of unilateral or bilateral increased parenchymal resistance in 27 of 68 (39.7%) vs nine of 44 (20.4%) with CHF and normal parenchymal resistance. One renal artery angioplasty was performed in a patient with unilateral renal artery stenosis and fibromuscular dysplasia.
Renal artery stenosis is extremely uncommon in patients undergoing RDS for RF, indicating that ischemic nephropathy is rarely a cause of RF in these patients. Abnormally increased renal parenchymal resistance is frequently found in patients being evaluated for RF and is associated with increasing creatinine and age. A diagnosis of CHF is also more common in patients with increased parenchymal resistance. Although patients who undergo RDS for RF rarely require renal artery interventions, ultrasound indices of parenchymal resistance may serve as a marker for renal disease and cardiovascular morbidity. Further studies are required to determine the prognostic significance of these ultrasound findings in the setting of RF.
尽管肾双功扫描（RDS）的常见适应证包括高血压（HT）和肾衰竭（RF），但RDS在评估RF患者中的作用尚不清楚。本研究的目的是确定在RF患者中具有预测或鉴别价值的超声检查结果，并确定因RDS检查结果而接受肾动脉干预的患者。
我们对2010年1月1日至2010年6月30日期间连续转诊至经社会间认证委员会认可的血管实验室进行首次RDS检查的214例患者进行了回顾性研究。RDS包括对主要肾血管和肾实质的直接超声评估。肾动脉直径减少≥60%的显著狭窄表现为肾动脉/主动脉速度比≥3.5，而实质阻力异常增加表现为舒张末期比率≤0.3。
我们根据RDS的适应证将患者分为两组：第一组（仅HT，n = 102）和第二组（仅RF或合并HT，n = 112）。当将第一组与第二组进行比较时，在性别（男性分别为50%和67%；P = 0.013）、年龄（50.9±18.5岁和60.0±14.8岁；P < 0.001）、平均动脉压（103.1±18.8和85.7±17.0 mmHg；P < 0.001）和肌酐（0.95±0.35和2.25±1.07 mg/dL；P < 0.001）方面存在显著差异。在第一组患者中，86例（84.3%）实质阻力正常，而在第二组患者中，68例（60.7%）单侧或双侧实质阻力异常增加（P < 0.001）。在第一组6例患者和第二组3例患者中发现单侧或双侧肾动脉狭窄（P = 0.315）。对第二组患者的评估显示，68例中有27例（39.7%）诊断为失代偿性充血性心力衰竭（CHF）且存在单侧或双侧实质阻力增加，而CHF且实质阻力正常的44例中有9例（20.4%）。1例单侧肾动脉狭窄并纤维肌发育异常的患者接受了肾动脉血管成形术。
在因RF接受RDS检查的患者中，肾动脉狭窄极为罕见，这表明缺血性肾病很少是这些患者RF的原因。在接受RF评估的患者中经常发现肾实质阻力异常增加，且与肌酐升高和年龄增长相关。CHF的诊断在实质阻力增加的患者中也更常见。尽管因RF接受RDS检查的患者很少需要肾动脉干预，但实质阻力的超声指标可能作为肾病和心血管疾病发病率的标志物。需要进一步研究以确定这些超声检查结果在RF背景下的预后意义。
