Objective To explore the application value of improving the operation method of the coaxial microcatheter system to increase the recanalization rate of long-segment occluded blood vessels in the lower extremity arteries.Methods Eleven patients with long-segment occlusion of the lower extremity arteries were selected.Firstly,the angiographic catheter was sent to about 3-4 cm proximal to the occluded segment to provide support and direction control of the coaxial microcatheter system.Then,the microcathe-ter was sent to about 1 cm proximal to the occluded segment through the angiographic catheter,and the microguide wire was sent to the occluded segment,making the tip of the guide wire closely adhere to the occluded segment.The guide wire was fixed by using the guide wire controller to ensure that the guide wire in the blood vessel was always about 1 cm exposed outside the microcatheter.Meanwhile,the microcatheter and the microguide wire were rotated to make the tip form a"spring"shape similar to that of a pipe-line dredging machine,so that the coaxial microcatheter system could pass through the occluded segment of the blood vessel in this shape.After confirmed that the microcatheter had entered the lumen of the distal outflow tract blood vessel,the subsequent interven-tional treatment was completed according to the conventional method.Results Eleven patients with long-segment occluded blood vessels in the lower extremity arteries were successfully treated with improving the operation method of the coaxial microcatheter system to dredge the occluded segment,and completed the interventional treatment of the affected limb blood vessels without vascu-lar rupture,vascular bleeding or arterial dissection.Conclusion Using the improved operation method of the coaxial microcatheter system to dredge the long-segment occluded blood vessels of the lower extremity arteries is simple,safe and has a high success rate,which is worthy of clinical promotion.

Objective To explore the application value of improving the operation method of the coaxial microcatheter system to increase the recanalization rate of long-segment occluded blood vessels in the lower extremity arteries.Methods Eleven patients with long-segment occlusion of the lower extremity arteries were selected.Firstly,the angiographic catheter was sent to about 3-4 cm proximal to the occluded segment to provide support and direction control of the coaxial microcatheter system.Then,the microcathe-ter was sent to about 1 cm proximal to the occluded segment through the angiographic catheter,and the microguide wire was sent to the occluded segment,making the tip of the guide wire closely adhere to the occluded segment.The guide wire was fixed by using the guide wire controller to ensure that the guide wire in the blood vessel was always about 1 cm exposed outside the microcatheter.Meanwhile,the microcatheter and the microguide wire were rotated to make the tip form a"spring"shape similar to that of a pipe-line dredging machine,so that the coaxial microcatheter system could pass through the occluded segment of the blood vessel in this shape.After confirmed that the microcatheter had entered the lumen of the distal outflow tract blood vessel,the subsequent interven-tional treatment was completed according to the conventional method.Results Eleven patients with long-segment occluded blood vessels in the lower extremity arteries were successfully treated with improving the operation method of the coaxial microcatheter system to dredge the occluded segment,and completed the interventional treatment of the affected limb blood vessels without vascu-lar rupture,vascular bleeding or arterial dissection.Conclusion Using the improved operation method of the coaxial microcatheter system to dredge the long-segment occluded blood vessels of the lower extremity arteries is simple,safe and has a high success rate,which is worthy of clinical promotion.