Study On The Relationship Between Iliac Vein Stenosis And Deep Vein Thrombosis Of Lower Extremity

Background:Iliac vein stenosis,also called iliac vein compression syndrome(IVCS),refers to the syndrome of local stenosis,lumen occlusion or intraluminal adhesion caused by the compression of the left iliac vein by the right iliac artery before it flows into the inferior vena cava.Iliac vein compression can cause lower extremity venous hypertension and affect valve function and venous return.Patients often present with varicose veins of the lower extremities and a series of symptoms of chronic venous insufficiency.It could cause deep venous thrombosis to block blood vessels later,which becomes an important factor of high incidence of DVT in left lower extremity.Deep venous thrombosis of the lower extremity is caused by various factors,which leads to abnormal blood coagulation in the veins of the lower extremity,leading to the blockage of the venous lumen,and then to the obstruction of the venous blood return of the lower extremity.If thrombosis is not treated quickly and properly,serious sequelae can occur.Patients often show varicose veins and nutritional changes such as ulceration and skin pigmentation,which is known as post thrombotic syndrome(PTS).If deep vein thrombosis is unstable,shedding and blocking the pulmonary artery along the blood flow,it may lead to pulmonary embolism,which often leads to fatal consequences.At the same time,pulmonary embolism is also the most serious consequence of DVT.At present,the main treatment measures for DVT are removing thrombus,reducing recurrence of thrombus and preventing fatal PE.Both primary and secondary factors can cause DVT.The primary factor is the abnormality of blood itself,such as deficiency of antithrombin,protein C and protein S.Secondary factors include iliac vein stenosis,vascular injury,limb immobilization,malignant tumor and so on.IVCS is often regarded as the most familiar secondary causes,the anatomical basis of DVT and an important factor of thrombosis recurrence.Therefore,the purpose of this study is to summarize the relationship between iliac vein stenosis and deep vein thrombosis of lower extremity,and to study how the degree of iliac vein stenosis affects the formation of DVT,and to summarize the changes of collateral circulation and hemodynamics in IVCS patients,so as to provide ideas for the prevention and treatment of DVT in IVCS patients.Methods:This review searches clincal researches on iliac vein stenosis and lower extremity deep vein thrombosis and screened out six studies with high correlation.We tried to analyze and summarize the specific relationship between them from the research methods and results,and to explore the influence of hemodynamic changes on thrombosis with iliac vein stenosis,so as to provide strategies for IVCS patients to prevent DVT.Results:Zhao et al.found that the incidence rate of DVT increased by 3.37 times when the iliac vein stenosis was more than 47.1%.Narayan et al.found that more than 70% compression will increase the risk of left DVT;Carr et al.found that the risk of DVT increased by 1.68 times and the risk of DVT increased by 2.18 times when the minimum diameter of lciv decreased by 1 mm and the stenosis of left iliac vein increased by 10%;Chen et al.found that the risk of DVT rised by 2.69 times when the minimum diameter of LCIV decreased by 1 mm and the risk of DVT increased by2.78 times when the stenosis rate of LCIV increased by 10%.When LCIV stenosis is greater than75%,the risk of DVT of the left lower extremity increased by 11 times and when LCIV diameter is less than 2.5 mm,the risk of DVT increased by 13.5 times;Wu et al found that the probability of DVT will increase by 10 times when the compression degree of the left common iliac vein exceeded50%;oguzkurt et al found that more than 70% iliac vein compression could indicate a higher risk of DVT.Three studies used about 70% as the threshold of high risk of DVT while two studies used about 50% as the threshold of high incidence of DVT,six studies considered that iliac vein compression was positively correlated with the risk of DVT,which means the greater the degree of iliac vein compression,the higher risk of lower extremity DVT.Conclusion:Iliac vein stenosis will lead to lower extremity deep vein thrombosis more easily as an independent factor and there is a positive relationship between the severity of iliac vein compression and thrombus risk,that is,the greater degree of vein compression can lead to a higher risk of DVT.When the iliac vein has serious stenosis(more than 70%),if combined with other thrombophilic factors,the risk of DVT will rises sharply.From the point of view of hydrodynamics,stenosis causes blood flow disorder and stasis,and slow venous blood flow is more likely to lead to blood coagulation and thrombosis.For patients with high risk of DVT,DVT should be prevented more actively.