老年中重度肾动脉狭窄患者的肾皮质血流灌注特点及其与肾功能的关系研究

The contrast-enhanced ultrasound imaging characteristics of renal cortical blood perfusion and the relationship of those with glomerular filtration rate in elderly patients with moderate-to-severe renal artery stenosis

目的探讨老年中重度肾动脉狭窄(RAS)患者超声造影肾皮质血流灌注的特点及其与肾小球滤过率(GFR)的关系。方法横断面自身对照研究。连续选取2017年6月至2018年12月诊治的59例老年单侧中重度RAS(50%~99%)患者,根据核素肾动态显像检测的患肾GFR,将59例患者分为轻度肾功能损伤组(18例,35>GFR≥25ml/min)、中度肾功能损伤组(37例,25>GFR≥15ml/min)和重度肾功能损伤组(4例,GFR<15ml·min^-1),并应用超声造影评估患肾的肾皮质血流灌注参数,应用Pearson相关性检验评估患肾皮质血流灌注参数与GFR的相关性。结果与轻度肾功能损伤组比较,中度肾功能损伤组的曲线下面积和上升支斜率减小,而重度肾功能损伤组的曲线下面积、上升支斜率、峰值强度、TTP和平均渡越时间变化更明显(均P<0.05)。与中度RAS组患者比较,重度RAS病变的皮质灌注参数曲线下面积和峰值强度、上升支斜率、GFR减小(均P<0.05),但TTP和平均渡越时间无变化。Pearson相关性检验结果提示,分肾皮质血流灌注参数曲线下面积(r=0.804)、上升支斜率(r=0.813)和峰值强度(r=0.733)与GFR呈正相关(均P<0.05),肾功能损伤分级(r=-0.721)、TTP(r=-0.744)和平均渡越时间(r=-0.743)均与GFR呈负相关(均P<0.05),而病变狭窄程度与GFR弱相关(r=-0.462)。结论对老年单侧中重度RAS患者,超声造影可反映随肾功能受损加重的分肾皮质血流灌注参数的变化,其中参数曲线下面积和上升支斜率与GFR强相关,肾动脉狭窄程度与肾功能弱相关,但仍需更多研究结果证实。

Objective To investigate the renal cortical perfusion parameters assessed by contrast-enhanced ultrasound(CEUS)in elderly patients with moderate-to-severe renal artery stenosis(RAS), and relationship of those with glomerular filtration rate(GFR). Methods A total of 59 elderly patients with unilateral moderate to severe RAS(50%-99%)admitted into Beijing Hospital during June 2017 to December 2018 were consecutively enrolled in the cross-sectional and self-control study.Based on the GFR assessed by radionuclide renal dynamic imaging, patients were divided into the mild-(35>GFR≥25 ml/min, n=18), moderate-(25>GFR≥15 ml/min, n=37)and severe renal dysfunction(GFR<15 ml·min^-1, n=4)groups.CEUS evaluated-renal cortical perfusion parameters, including area under curve(AUC), ascending slope(A), derived peak intensity(DPI), time to peak(TTP)and mean transit time(MTT), were compared among different levels of severity of renal dysfunction groups.Pearson correlation analysis was used to evaluate the relationship between CEUS imaging-evaluated renal cortical perfusion parameters and radionuclide renal dynamic imaging-assessed GFR. Results Compared with the mild renal dysfunction group, the moderate renal dysfunction group showed a reduced AUC and A(P<0.05), and the severe renal dysfunction group showed more markedly reduced AUC, A, DPI, TTP and MTT(P<0.05). Compared with the moderate renal dysfunction group, the severe renal dysfunction group showed a reduced AUC, A and GFR(P<0.05), while no significant differences in TTP and MTT were found.As far as relationship between renal cortical perfusion parameters and GFR were concerned, Pearson correlation analysis demonstrated that AUC(r=0.804), A(r=0.813)and DPI(r=0.733)were significantly and positively correlated with GFR(all P<0.05). However, renal function(r=-0.721), TTP(r=-0.744)and MTT(r=-0.743)were negatively correlated with GFR(P<0.05). And the degree of renal artery stenosis was poorly correlated with GFR(r=-0.462). Conclusions For elderly patients with unilateral moderate to severe RAS, contrast-enhanced ultrasonography can display the changes of renal cortical blood perfusion parameters along with the aggravation of renal function impairment.AUC and A are strongly positively correlated with GFR.The degree of renal artery stenosis is poorly correlated with renal function.And more studies are needed to confirm these findings.