合并静脉瘤的Cognard Ⅳ型硬脑膜动静脉瘘血流动力学特征的初步研究

Preliminary study on the hemodynamics of Cognard type Ⅳ dural arteriovenous fistulas with venous aneurysm

目的初步探讨合并静脉瘤的Cognard Ⅳ型硬脑膜动静脉瘘(DAVF)患者的血流动力学特征。方法回顾性纳入2017年7月至12月北京清华长庚医院神经外科收治的合并静脉瘤的Cognard Ⅳ型DAVF患者,共4例(7个静脉瘤),术前均无颅内出血。基于三维数字减影血管造影(3D-DSA)图像建立DAVF模型,采用计算流体力学数值模拟的方法进行血流动力学研究。结果7个静脉瘤内平均血流速度的中位数为0.030(0.002~1.567)m/s,引流静脉内为0.092(0.050~2.235)m/s,差异无统计学意义(P=0.248)。瘘区、静脉瘤、引流静脉平均压力的中位数分别为7 394.9(6 087.3~7 977.0)Pa、4 882.2(3 697.8~7 004.7)Pa、3 439.1(3 337.2~5 612.9)Pa;平均壁面切应力(WSS)的中位数分别为10.22(4.07~13.58)Pa、4.11(0.24~13.95)Pa、7.61(5.16~12.90)Pa。在静脉引流系统上,静脉瘤内的压力高于引流静脉内的压力,但差异无统计学意义(W=39,P=0.072);静脉瘤壁的平均WSS低于引流静脉壁的平均WSS,差异有统计学意义(W=8,P=0.040)。静脉瘤后的引流静脉上均存在明显的高WSS区,2例合并多发静脉瘤的患者,高WSS区位于其后静脉瘤的流入道区域。结论初步研究结果显示,引流静脉上的静脉瘤壁的WSS较低,静脉瘤后的引流静脉存在高WSS区。有关WSS与静脉瘤破裂及形成的关系有待进一步研究。

Objective To explore the hemodynamic features of venous aneurysms in Cognard type Ⅳ dural arteriovenous fistulas (DAVF). Methods Computational fluid dynamics analysis was conducted in 7 venous aneurysms of 4 patients who received endovascular treatment at Department of Neurosurgery, Beijing Tsinghua Changgung Hospital between July 2017 and December 2017. All 4 patients experienced no intracranial bleeding before intervention. Results Average flow velocity was 0.030 (0.002-1.567) m/s in the 7 aneurysms and 0.092 (0.050-2.235) m/s in drainage veins. The difference was not statistically significant (P=0.248). Average pressures in fistula area, venous aneurysm and drainage veins were 7 394.9(6 087.3-7 977.0) Pa, 4 882.2 (3 697.8-7 004.7) Pa and 3 439.1 (3337.2-5 612.9) Pa, respectively. Median values of average wall shear stress (WSS) were 10.22 (4.07-13.58) Pa in fistula area, 4.11 (0.24-13.95) Pa in venous aneurysms and 7.61 (5.16-12.90) Pa in drainage veins. On the draining system, average pressure in venous aneurysms were higher when compared with drainage veins, but the difference was not significant in statistics (W=39, P=0.072), however, average WSS were significantly lower in venous aneurysms (W=8, P=0.040). For the 2 cases with multiple venous aneurysms, high WSS area was identified in the inflow area of subsequent venous aneurysms. Conclusion Preliminary results have indicated that WSS of venous aneurysms is lower compared with drainage veins, and high WSS area is present on drainage veins distal to the venous aneurysm. The relationship between WSS and venous aneurysm rupture requires further validation in future studies.