Buijs Ruben V C, Zeebregts Clark J, Willems Tineke P, Vainas Tryfon, Tielliu Ignace F J
Department of Surgery, Division of Vascular Surgery, University Medical Center Groningen, Groningen, The Netherlands.
Department of Radiology, University Medical Center Groningen, Groningen, The Netherlands.
PLoS One. 2016 Jun 30;11(6):e0158042. doi: 10.1371/journal.pone.0158042. eCollection 2016.
In endovascular aortic aneurysm repair (EVAR), proximal type 1A endoleaks can occur as a result of hostile neck anatomy or over- or undersizing of the endograft. As the current standard is based on the diameter or average of the short and long axes in a central lumen reconstruction image, it can falter in irregularly shaped aortic necks. An alternative method is circumference-based, therefore minimizing the measurement error. In this study we aimed to assess the degree of discrepancy between both methods and the association of this discrepancy with the occurrence of endoleak type 1A.
All patients with early (<30 days post-operative) endoleak type 1A after elective EVAR at our center between 2004 and 2016 were identified for a retrospective case-control study. Control patients were matched based on hostile neck anatomy, such as calcification, thrombus, reverse taper, and β-angulation. The aortic neck diameter was measured using the traditional, diameter-based method as well as an alternative method, based on the circumference of the aortic neck.
In 482 EVAR patients, 18 early endoleak type 1A cases were found (3.9%). After exclusion, 12 cases remained and 48 matching controls were found. No significant differences were found between the two measuring methods at any level below the renal arteries. The inter-observer variability was significant for the D(mean) (0.4 ± 1.69 mm, P = .02) and was larger than the D(circ) method (-0.1 ± 1.03 mm, P = .35). In only four out of 12 cases the endograft size was 10-20% larger than the D(mean) and D(circ) measurements. The differences between the diameter of the D(mean) and D(circ) and the chosen endograft were smaller for the case group (-8 ± 25.6% and -7 ± 24%) than for the control group. (-12.4 ± 12.4% and -11 ± 10.7%).
The difference between the D(mean) and D(circ) methods for aortic neck measurement was not large enough to play a significant role in the incidence of endoleak type 1A. Inadequate oversizing and considerable β-angulation of the aortic neck may have been the cause of endoleak type 1A in this population. Robust and well-investigated sizing methods are paramount for accurate endograft sizing and prevention of endoleak type 1A. Therefore the lack of studies in this field and a sizeable inter-observer variability do not justify the widespread reliance on the traditional diameter-based methods for endograft sizing.
在血管腔内主动脉瘤修复术（EVAR）中，1A型近端内漏可能由于颈部解剖结构不佳或血管内移植物尺寸过大或过小而发生。由于当前标准基于中心腔重建图像中的直径或短轴与长轴的平均值，在形状不规则的主动脉颈部可能会出现偏差。一种替代方法是基于周长的方法，因此可将测量误差降至最低。在本研究中，我们旨在评估两种方法之间的差异程度以及这种差异与1A型内漏发生的关联。
对2004年至2016年间在我们中心接受择期EVAR术后早期（术后<30天）出现1A型内漏的所有患者进行回顾性病例对照研究。根据颈部解剖结构不佳情况（如钙化、血栓、反向锥度和β角）匹配对照患者。使用传统的基于直径的方法以及基于主动脉颈部周长的替代方法测量主动脉颈部直径。
在482例EVAR患者中，发现18例早期1A型内漏病例（3.9%）。排除后，剩余12例病例，并找到48例匹配对照。在肾动脉以下的任何水平，两种测量方法之间均未发现显著差异。观察者间变异性对于D（均值）而言具有显著性（0.4±1.69mm，P = 0.02），且大于D（周长）方法（-0.1±1.03mm，P = 0.35）。在12例病例中，仅4例的血管内移植物尺寸比D（均值）和D（周长）测量值大10 - 20%。病例组中D（均值）和D（周长）的直径与所选血管内移植物之间的差异（-8±25.6%和-7±24%）小于对照组（-12.4±12.4%和-11±10.7%）。
D（均值）和D（周长）方法在主动脉颈部测量上的差异不足以在1A型内漏的发生率中起重要作用。主动脉颈部尺寸过大不足和相当大的β角可能是该人群中1A型内漏的原因。可靠且经过充分研究的尺寸测量方法对于准确的血管内移植物尺寸确定和预防1A型内漏至关重要。因此，该领域研究的缺乏以及可观的观察者间变异性无法证明广泛依赖传统的基于直径的方法进行血管内移植物尺寸确定是合理的。
