tailieunhanh - Emergency Vascular Surgery A Practical Guide - part 9

Bệnh viện dựa trên các nghiên cứu hiện nay một tỷ lệ lớn hơn của thuyên tắc phổi (PE), trong khi đoàn hệ cộng đồng có bệnh nhân huyết khối hơn. Biểu hiện dao động từ một huyết khối bề mặt hoặc một huyết khối tĩnh mạch sâu (DVT) nhỏ sản xuất chỉ có triệu chứng phút một DVT | 160 Chapter 13 incidence varies with the population studied and increases with age. Hospital-based studies present a larger proportion of pulmonary embolism PE whereas community cohorts have more thrombosis patients. Manifestations range from a superficial thrombophlebitis or a minor deep venous thrombosis DVT that produces only minute symptoms to a DVT with massive embolism to the lungs threatening the patient s life. While open surgical treatment of venous thromboembolic disease is rarely indicated it is helpful to have basic knowledge about diagnosis pathogenesis and anticoagulation treatment. This is important for differential diagnosis and for the few instances when emergency endovascular or open surgical treatment is indicated. This chapter will also describe the technique for surgical and endovascular treatment of acute DVT. Pathogenesis When DVT occurs clots have usually formed in the small deep veins in the calf. Patients afflicted have hypercoagulative disorders are taking medications that affect clotting that make them susceptible to venous thrombosis has malignancy or has been immobilized for a larger period. The clot causes a local inflammation in the venous wall and adjacent tissue that may make the calf tender. Because the small veins in the calf are paired the clot does not cause significant venous obstruction or distal edema. Flow in the obstructed vein will decrease however which increases the risk for continuing clot formation. The clot will then grow in a proximal direction and continue to obstruct more veins. Also at this stage distal edema is quite uncommon because collateral flow is extensive in the legs and significant swelling does not occur until the common femoral vein is obstructed. At this level the outflow from the deep femoral superficial and great saphenous vein is affected. Continued obstruction causing near occlusion of all the main veins in the leg and pelvis can lead to a dreaded condition called phlegmasia cerulea do-lens