Application Of Equidistant Measurement In Evaluating The Morphology Of The Iliac Veins

Objective: The equidistant measurement is used to explore the morphological characteristics of the iliac vein in patients with non-thrombotic left iliac vein compression syndrome with venous insufficiency and to analyze the correlation and difference among various factors.Method: The multiplane venography data of 108 patients with non-thrombotic iliac vein compression syndrome treated in the first affiliated Hospital of Bengbu Medical College from September 1,2019 to December 31,2020 were prospectively selected for related study.General data such as age,sex,BMI,CEAP grade and RVCSS score were collected.The diameter of IVC,the diameter of iliac vein at 0mm,20 mm,40mm,60 mm and 80 mm of LCIV were evaluated by equidistant measurement,the angle between IVC and LCIV and the length of LCIV were measured,the formation of collateral branches was recorded,and the average model of iliac vein was established.Mean and standard deviation were used to describe the diameter shape;t-test and variance test were used to analyze the surgical improvement,morphological characteristics of iliac vein and the difference of collateral formation;Pearson and Spearman correlation coefficients were used to analyze the correlation between general data and iliac vein measurement data.Result: Angioplasty was successfully performed in all lesions,with a technical success rate of 100%,Blood flow improvement rate 100%,and no adverse events occurred during the perioperative period.Before and after surgical intervention,the average reduction of 2.6mm in the vein contraction group and the average increase of2.3mm in the dilatation group.There was statistical significance between the two groups before and after surgical intervention（Reduction group,P=0.00 < 0.05;Growth group,P=0.00<0.05;）.The LCIV diameter of the compressed iliac vein was15.4 ±2.4mm,LEIV and 11.1 ±1.8mm.The LCIV after decompression was15.6±1.9mm,LEIV and 11.2 ±1.8mm.The IVC was 19.6 ±3.2mm and the length of LCIV was 61.3±11.0mm.The angle between IVC and LCIV was 36.4°±15.8°.The formation of collateral branches was statistically significant in terms of sex and LEIV diameter distribution（P<0.05）.IVC and LEIV have statistical significance in LCIV length distribution（P<0.05）.The diameter of IVC was positively correlated with the diameter of LCIV and LEIV（r=0.542,P < 0.05;r=0.273,P < 0.05;）.There was a positive correlation between LCIV diameter and LEIV diameter（r=0.479,P<0.05;）.The diameter of LEIV was negatively correlated with the length of LCIV and the formation of collateral branches（r=-0.243,P<0.05;r=-0.219,P<0.05;）.The length of LCIV was negatively correlated with the angle between IVC and LCIV（r=-0.295,P<0.05;）.Conclusion: The common shape of iliac vein is "thick short-large angle type" or "slender-small angle type".the equidistant measurement is simple,rapid and convenient to evaluate the morphology of iliac vein,and can provide accurate,reliable and effective morphological evaluation.