Duque Juan C, Martinez Laisel, Tabbara Marwan, Parikh Punam, Paez Angela, Selman Guillermo, Salman Loay H, Velazquez Omaida C, Vazquez-Padron Roberto I
Katz Family Division of Nephrology, Miller School of Medicine, University of Miami, Miami, FL, USA.
DeWitt Daughtry Family Department of Surgery, Miller School of Medicine, University of Miami, Miami, FL, USA.
J Vasc Access. 2020 Mar;21(2):161-168. doi: 10.1177/1129729819863584. Epub 2019 Oct 14.
The venous vasa vasorum is the mesh of microvessels that provide oxygen and nutrients to the walls of large veins. Whether changes to the vasa vasorum have any effects on human arteriovenous fistula outcomes remains undetermined. In this study, we challenged the hypothesis that inadequate vascularization of the arteriovenous fistula wall is associated with maturation failure.
DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: This case-control pilot study includes pre-access veins and arteriovenous fistula venous samples (i.e. tissue pairs) from 30 patients undergoing two-stage arteriovenous fistula creation (15 matured and 15 failed to mature). Using anti-CD31 immunohistochemistry, we quantified vasa vasorum density and luminal area (vasa vasorum area) in the intima, media, and adventitia of pre-access veins and fistulas. We evaluated the association of pre-existing and postoperative arteriovenous fistula vascularization with maturation failure and with postoperative morphometry.
Vascularization of veins and arteriovenous fistulas was predominantly observed in the outer media and adventitia. Only the size of the microvasculature (vasa vasorum area), but not the number of vessels (vasa vasorum density), increased after arteriovenous fistula creation in the adventitia (median vasa vasorum area 1366 µm/mm (interquartile range 495-2582) in veins versus 3077 µm/mm (1812-5323) in arteriovenous fistulas, < 0.001), while no changes were observed in the intima and media. Postoperative intimal thickness correlated with lower vascularization of the media ( 0.53, = 0.003 for vasa vasorum density and 0.37, = 0.045 for vasa vasorum area). However, there were no significant differences in pre-existing, postoperative, or longitudinal change in vascularization between arteriovenous fistulas with distinct maturation outcomes.
The lack of change in intimal and medial vascularization after arteriovenous fistula creation argues against higher oxygen demand in the inner walls of the fistula during the vein to arteriovenous fistula transformation. Postoperative intimal hyperplasia in the arteriovenous fistula wall appears to thrive under hypoxic conditions. Vasa vasorum density and area by themselves are not predictive of maturation outcomes.
静脉血管滋养管是为大静脉壁提供氧气和营养物质的微血管网。血管滋养管的变化是否会对人体动静脉内瘘的结果产生影响仍未确定。在本研究中，我们对动静脉内瘘管壁血管化不足与成熟失败相关这一假说进行了验证。
设计、设置、参与者与测量：本病例对照试点研究纳入了30例行两阶段动静脉内瘘成形术患者的术前静脉和动静脉内瘘静脉样本（即组织对）（15例成熟，15例未成熟）。使用抗CD31免疫组织化学方法，我们量化了术前静脉和内瘘的内膜、中膜和外膜中的血管滋养管密度和管腔面积（血管滋养管面积）。我们评估了术前和术后动静脉内瘘血管化与成熟失败以及与术后形态学之间的关联。
静脉和动静脉内瘘的血管化主要见于外中膜和外膜。动静脉内瘘形成后，仅外膜中的微血管大小（血管滋养管面积）增加，而血管数量（血管滋养管密度）未增加（静脉中血管滋养管面积中位数为1366μm/mm（四分位间距495 - 2582），而动静脉内瘘中为3077μm/mm（1812 - 5323），<0.001），内膜和中膜未观察到变化。术后内膜厚度与中膜血管化程度较低相关（血管滋养管密度r = 0.53，P = 0.003；血管滋养管面积r = 0.37，P = 0.045）。然而，具有不同成熟结果的动静脉内瘘在术前、术后或血管化的纵向变化方面无显著差异。
动静脉内瘘形成后内膜和中膜血管化缺乏变化，这与静脉向动静脉内瘘转变过程中内瘘内壁对氧气需求增加的观点相悖。动静脉内瘘管壁术后内膜增生似乎在低氧条件下更为活跃。血管滋养管密度和面积本身并不能预测成熟结果。
