Clinical Research Of Establishment Of Collateral Circulation And Its Significance After Lower Extremity Deep Vein Thrombosis

Objective:To explore the influencing factors of the establishment of collateral reflux in lower limb deep venous thrombosis and the influence of the establishment of collateral reflux on subsequent treatment.Methods:The clinical data of 383 DVT patients treated in the interventional department of the affiliated hospital of Zunyi medical university from January 2018 to October 2019were collected and the patients data who eligible for inclusion were retrospective analysed（the first onset was unilateral limb DVT;received intravenous angiography examination;clear onset time;After the diagnosis,continued to receive thrombus treatment and follow-up according to the doctor’s advice）.All patients were initially diagnosed as DVT by Doppler ultrasound examination of lower limb veins,and further angiography was performed to determine thrombosis.Follow-up was conducted for 3 months after treatment.The patients were divided into two groups according to the presence or absence of collateral reflux by venography when receiving thrombus treatment:group A which collateral reflux was establishment and group B which was no collateral reflux.Main outcome measures:Sex,age,course of disease before treatment of thrombus,limb involvement of thrombus,thrombus classification,static venous pressure of bilateral iliac vein and both ends of thrombus in patients with isolated iliac vein thrombosis,peripheral diameter at 10cm above and below bilateral knee joint before and 2 weeks after endovascular treatment,venous blood flow patency score and thrombus clearance rate,and iliac vein patency rate 3 months after endovascular treatment.All the data were processed and analyzed by SPSS 18.0 statistical software and Excel 2016 software.the measured data were in accordance with the normal distribution expressed by（??±s）,which the comparison between groups was tested by independent sample t test and the comparison within groups was tested by paired sample t test,and the others were not in accordance with the normal distribution expressed by M（P25,P75）which were test by Mann-Whitney U rank sum test,the counting data were analyzed by chi-square test or exact probability method,P<0.05 was statistically significant.Results:There were 115 patients included in the study,including 61 in group A and 54 in group B.Group A:there were 23 males and 38 females,which age were 18-88 years and average age were（56.38±15.43）years old,among them 53 patients were left lower limbs and 8 patients were right lower limbs,the thrombosis types including 18 cases for central,12 cases for peripheral,31 cases for mixed,the course of disease before thrombosis therapy were 10（3.50,20）days,and there were 15 patients with solitary iliac vein thrombosis.Group B:there were 29 males and 25 females,which age were 21-86 years and average age were（57.30±15.55）years old,among them 45 patients were left lower limbs and 9 patients were right lower limbs,the thrombosis types including 16 cases for central,21 cases for peripheral,17 cases for mixed,the course of disease before thrombosis therapy were 5（2,10）days,and there were 14 patients with solitary iliac vein thrombosis.There were no significant difference in gender,age,and the limb of thrombus involvement in the two groups.There were significant differences in the course of disease（Z=-3.03,P<0.05）and thrombosis type（?²=6.52,P=0.04）between the two groups.The difference of static venous pressure between bilateral iliac vein（Z=-3.86,P<0.05）and at both ends of the thrombus（Z=-4.57,P<0.05）were statistically significant.There were statistically significant differences in the degree of subsidence of swelling in the thighs and legs respectively before and after endovascular treatment in the two groups(Z_thigh=-3.87,Z_leg=-4.31,P<0.05 of all of them),and thrombus clearance rate（Z=-2.56,P<0.05）,and iliac vein patency rate with 3 months after intravascular treatment（P=0.03）.Conclusion:The establishment of collateral reflux of DVT is mainly related to the course of disease before the treatment and the type of thrombosis,as well as the static venous pressure difference between the two sides of the iliac vein and between at the both ends of thrombosis.The establishment of collateral reflux could reduce the swelling of the affected limb,but also has some degree of influence on the clearance of thrombosis and the maintenance of venous reflux access after endovascular treatment.