CFD Modeling of Vascular Hemodynamics in Nutcracker Syndrome

doi:10.12114/j.issn.1007-9572.2022.0324

Abstract

Abstract:

Background

Recent research on nutcracker syndrome has focused mainly on exploring the value and criteria of various imaging modalities for the diagnosis of the disease. Providing more quantitative parameters related to the lesion through non-invasive modalities has been a focus of studies on clinical diagnosis and treatment of nutcracker syndrome. However, no relevant data are available on pressure changes in left renal vein and inferior vena cava and hemodynamic parameters in left renal due to different degrees of stenosis in the left renal vein.

Objective

To develop acomputational fluid dynamics (CFD) model to obtain the hemodynamics of individuals with nutcracker syndrome, to explore the relationship of blood flow velocity, wall static pressure, and wall shear stress with the change of vessel disease.

Methods

70 patients with nutcracker syndrome were sampled from the Affiliated Hospital of Xuzhou Medical University from September 2019 to March 2021. CFD was used to simulate the intravascular blood flow in the left renal vein of real-world patients with nutcracker syndrome based on CT enhanced images. The hemodynamic characteristics, including vascular diameter and flow velocity, were obtained and compared with those measured by ultrasound.

Results

The left renal vein's intake pressure was high, but the stenosis and exit pressures were low. From the inlet to the outlet, the pressure successively dropped. Except for the narrow region, the wall shear stress was smaller, and the closer to the center of the stenosis, the higher the shear stress. The blood flow velocity in the stenosis was significantly higher than that in other areas of the left renal vein, which was consistent with the result of ultrasonography.

Conclusion

The successfully developed vascular model, The hemodynamic change rules of nutcracker syndrome patients include that the inner diameter of the left renal vein becomes smaller and the flow velocity increases at the stenosis.

Key words: Nutcracker syndrome, Imaging, Hemodynamics, Simulation

摘要：

背景

目前胡桃夹综合征的研究主要集中在探讨各种影像学方法对该病的诊断价值及其诊断标准方面。通过无创方式提供更多与病变相关的量化参数，是胡桃夹综合征临床诊断、治疗依据研究的重点。然而，对左肾静脉不同狭窄程度引起左肾静脉与下腔静脉压力差值、左肾静脉血流动力学参数的变化未见相关的数据资料。

目的

通过计算流体力学（CFD）的方法对胡桃夹综合征患者进行血流动力学数值的模拟，探讨血液流速、静压力、壁面切应力与血管狭窄程度的关系。

方法

选择2019年9月至2021年3月在徐州医科大学附属医院就诊的70例胡桃夹综合征患者为研究对象。以真实患者的左肾静脉CT增强图像为基础，应用CFD方法对胡桃夹综合征患者左肾静脉进行血管内血流模拟计算，获得患者的血流动力学特征，并与超声测得的血管内径及流速比较。

结果

左肾静脉血流入口处的压力显示为高压，狭窄处与出口处显示为低压，从入口到出口呈现压力递减的特点。壁面切应力除狭窄处外均呈现较低的壁面切应力，越靠近狭窄中心位置，切应力越高，狭窄处的血流速度明显高于左肾静脉其他区域，与超声检查结果一致。

结论

本研究成功建立了胡桃夹综合征患者的血管模型，胡桃夹综合征患者血流动力学变化规律为狭窄处左肾静脉内径变小，流速增快。

关键词: 胡桃夹综合征, 影像学, 血流动力学, 数值模拟

Shikun ZHANG,Lu TANG,Xiaojie XU, et al. CFD Modeling of Vascular Hemodynamics in Nutcracker Syndrome[J]. Chinese General Practice, 2022, 25(27): 3409-3414. DOI: 10.12114/j.issn.1007-9572.2022.0324.
张世坤,唐璐,徐小杰等. 胡桃夹综合征血流动力学的血管建模研究[J]. 中国全科医学, 2022, 25(27): 3409-3414. DOI: 10.12114/j.issn.1007-9572.2022.0324.

Figures/Tables 4

Figure 1 Three-dimensional model and initial model on left renal vein and its adjacent vessels

Figure 2 Grid model generated based onthe left renal vein

Figure 3 Hemodynamic changes of theleft renal vein

Table 1 Ultrasonic examination of enrolled patients

检查体位	左肾静脉内径（mm）		左肾静脉流速（cm/s）
检查体位	狭窄处^a	入口处^b	狭窄处	入口处
平卧位	2.3±0.3	5.0±0.6	65.53±15.66	32.27±12.08
站立位	1.9±0.4	8.6±0.9	108.76±21.19	27.43±11.75

References 30

[1]	史点顺，樊静，洪建军，等. 声辐射力脉冲弹性成像联合肾功能定量评估胡桃夹综合征患者肾实质硬度[J]. 现代医药卫生，2019，35（9）：1339-1341，1345.
[2]	HANSRAJ N，HAMDI A，KHALIFEH A，et al. Nutcracker syndrome：case report on the management of recurrent stenosis after stenting[J]. Vasc Endovascular Surg，2017，51（4）：203-208. DOI：10.1177/1538574417700012.
[3]	CHOI S H，KIM J S，SHIN T S，et al. Nutcracker syndrome diagnosed with 3-dimensional computed tomography angiography[J]. Korean J Urol，2009，50（7）：711. DOI：10.4111/kju.2009.50.7.711.
[4]	ER A L，UZUNLULU N，GUZELBEY T，et al. The nutcracker syndrome：the usefulness of different MRI sequences for diagnosis and follow-up[J]. Clin Imaging，2019，55：144-147. DOI：10.1016/j.clinimag.2019.02.003.
[5]	KIM S H，CHO S W，KIM H D，et al. Nutcracker syndrome：diagnosis with Doppler US[J]. Radiology，1996，198（1）：93-97. DOI：10.1148/radiology.198.1.8539413.
[6]	SHIN J I，PARK J M，LEE S M，et al. Factors affecting spontaneous resolution of hematuria in childhood nutcracker syndrome[J]. Pediatr Nephrol，2005，20（5）：609-613. DOI：10.1007/s00467-004-1799-z.
[7]	SHIN J I，PARK J M，LEE J S，et al. Doppler ultrasonographic indices in diagnosing nutcracker syndrome in children[J]. Pediatr Nephrol，2007，22（3）：409-413. DOI：10.1007/s00467-006-0319-8.
[8]	LUO X L，QIAN G N，XIAO H，et al. Posterior nutcracker syndrome associated with interrupted left inferior vena cava with azygos continuation and retroaortic right renal vein[J]. Korean J Radiol，2012，13（3）：345-349. DOI：10.3348/kjr.2012.13.3.345.
[9]	邓连桂，王晓波，黄佩贤，等. 彩色多普勒超声对胡桃夹综合征的诊断研究[J]. 现代医用影像学，2017，26（5）：1229-1231，1237.
[10]	ULUSAN S，KOC Z. Left inferior vena cava associated with nutcracker phenomenon[J]. Firat Tip Dergisi，2007，12（2）：151-153.
[11]	CUÉLLAR I CALÀBRIA H，QUIROGA GÓMEZ S，SEBASTIÀ CERQUEDA C，et al. Nutcracker or left renal vein compression phenomenon：multidetector computed tomography findings and clinical significance[J]. Eur Radiol，2005，15（8）：1745-1751. DOI：10.1007/s00330-005-2688-y.
[12]	ALBAUT M，NASSER S，DRAGOMIR M，et al. Nutcracker syndrome：the role of three-dimensional imaging for the diagnosis[J]. DiagnInterv Imaging，2016，97（9）：929-930. DOI：10.1016/j.diii.2016.05.002.
[13]	LIDOVE O，OROZCO R，GUCRY B，et al. A young woman with intermittent macroscopic haematuria[J]. Nephrol Dial Transplant，2001，16（4）：853-855. DOI：10.1093/ndt/16.4.853.
[14]	TAKEBAYASHI S，UEKI T，IKEDA N，et al. Diagnosis of the nutcracker syndrome with color Doppler sonography：correlation with flow patterns on retrograde left renal venography[J]. AJR Am J Roentgenol，1999，172（1）：39-43. DOI：10.2214/ajr.172.1.9888735.
[15]	YUN S J，LEE J M，NAM D H，et al. Discriminating renal nutcracker syndrome from asymptomatic nutcracker phenomenon using multidetector computed tomography[J]. Abdom Radiol （NY），2016，41（8）：1580-1588. DOI：10.1007/s00261-016-0717-8.
[16]	梁斌，黄晓强，董家鸿，等. 门静脉变异致肝门部胆管狭窄形成的胆管胡桃夹征[J]. 中华消化外科杂志，2011，10（1）：74-76. DOI：10.3760/cma.j.issn.1673-9752.2011.01.024.
[17]	ZHANG H K，LI M，JIN W，et al. The left renal entrapment syndrome：diagnosis and treatment[J]. Ann Vasc Surg，2007，21（2）：198-203. DOI：10.1016/j.avsg.2006.10.021.
[18]	FU W J，HONG B F，XIAO Y Y，et al. Diagnosis of the nutcracker phenomenon by multislice helical computed tomography angiography[J]. Chin Med J （Engl），2004，117（12）：1873-1875.
[19]	HOSOTANI Y，KIYOMOTO H，FUJIOKA H，et al. The nutcracker phenomenon accompanied by renin-dependent hypertension[J]. Am J Med，2003，114（7）：617-618. DOI：10.1016/s0002-9343(03)00091-3.
[20]	CHIESA R，ANZUINI A，MARONE E M，et al. Endovascular stenting for the nutcracker phenomenon[J]. J Endovasc Ther，2001，8（6）：652-655. DOI：10.1177/152660280100800620.
[21]	CHEN Y M，WANG I K，NGK K，et al. Nutcracker syndrome：an overlooked cause of hematuria[J]. Chang Gung Med J，2002，25（10）：700-705.
[22]	ANDRIANNE R，LIMET R，WALTREGNY D，et al. Hematuria caused by nutcracker syndrome：peroperative confirmation of its presence[J]. Prog Urol，2002，12（6）：1323-1326.
[23]	SCHOLBACH T. From the nutcracker-phenomenon of the left renal vein to the midline congestion syndrome as a cause of migraine，headache，back and abdominal pain and functional disorders of pelvic organs[J]. Med Hypotheses，2007，68（6）：1318-1327. DOI：10.1016/j.mehy.2006.10.040.
[24]	AHMED K，SAMPATH R，KHAN M S. Current trends in the diagnosis and management of renal nutcracker syndrome：a review[J]. Eur J Vasc Endovasc Surg，2006，31（4）：410-416. DOI：10.1016/j.ejvs.2005.05.045.
[25]	DEMIREL S，CHEN D，MEI Y，et al. Comparison of morphological and rheological conditions between conventional and eversion carotid endarterectomy using computational fluid dynamics—a pilot study[J]. Vascular，2015，23（5）：474-482. DOI：10.1177/1708538114552836.
[26]	COOGAN J S，CHAN F P，LADISA J F Jr，et al. Computational fluid dynamic simulations for determination of ventricular workload in aortic arch obstructions[J]. J Thorac Cardiovasc Surg，2013，145（2）：489-495. DOI：10.1016/j.jtcvs.2012.03.051.
[27]	POULLIS M. Computational fluid dynamic analysis to prevent aortic root and valve clots during left ventricular assist device support[J]. J Extra Corpor Technol，2012，44（4）：210-215.
[28]	KURKLINSKY A K，ROOKE T W. Nutcracker phenomenon and nutcracker syndrome[J]. Mayo Clin Proc，2010，85（6）：552-559. DOI：10.4065/mcp.2009.0586.
[29]	FITOZ S，YALCINKAYA F. Compression of left inferior vena cava：a form of nutcracker syndrome[J]. J Clin Ultrasound，2008，36（2）：101-104. DOI：10.1002/jcu.20365.
[30]	罗晓莉，朱建平，江丽，等. 后胡桃夹综合征患者彩色多普勒超声表现[J]. 中华医学超声杂志（电子版），2012，9（2）：171-174. DOI：10.3877/cma.j.issn.1672-6448.2012.02.017.