Intervention combined with surgery in the treatment of lower extremity deep vein thrombosis [Abstract] Objective To initially discuss and summarize the efficacy of surgery combined with intervention in the treatment of lower extremity deep vein thrombosis (DVT). Methods: Retrospective analysis of the methods and effects of surgery combined with intervention in a total of 42 limbs of 40 patients (DVT) treated in the last 2 years, including 8 cases of old cast thrombosis in the main iliofemoral vein, 25 cases of fresh thrombosis secondary to stenosis or occlusion of the opening of the common iliac vein, 5 cases of unilateral fresh thrombosis, and 2 cases of fresh thrombosis in the inferior vena cava and both lower limbs secondary to filter placement. The main use of femoral vein dissection in the affected limb was interventional embolization combined with balloon dilation and/or stenting. RESULTS: The inferior vena cava and deep veins were opened in all 40 patients. Among them, iliac vein stenting was performed in 19 cases; balloon dilation in 14 cases; and artificial vessel replacement of the deep femoral vein in 1 case. The average follow-up was 10 months, and all patients showed significant improvement in the symptoms of the affected limbs, and the ultrasound or imaging showed that the deep vein on the affected side was flowing smoothly. Conclusion: Surgery combined with intervention has good effect in the treatment of deep vein thrombosis, which is worthy of further study and promotion. Forty cases of patients with DVT were treated by the method of intervention combined with surgery, and satisfactory results were achieved, which are reported as follows. Clinical data In this group of 40 patients with DVT, 23 cases were male and 17 cases were female. The ages ranged from 32 to 87 years. The lesion involved the left lower extremity in 22 cases, the inferior vena cava under the filter and both lower extremities in 2 cases, and the right lower extremity in 16 cases. The lesions involved the main stem of the iliofemoral vein in all patients and were of the completely occluded type. 32 patients had significant swelling of the affected limbs at an earlier stage, and some of them had developed femoral bruising and swelling. In two of them, intra-filter thrombosis and bilateral lower extremity iliofemoral deep vein thrombosis occurred after inferior vena cava filter placement in an outside hospital. 8 patients with intermediate to advanced swelling had varying degrees of swelling, but all of them showed weakness and increased swelling after walking, and some of them had clinical symptoms of post-deep vein thrombosis syndrome such as ulcers in the lower extremities that did not heal. All patients were confirmed by ultrasound before surgery. The preoperative diagnosis was clear in the whole group of cases. Surgical methods: All procedures were performed under DSA. The inferior vena cava filter was placed on the healthy side to prevent pulmonary infarction caused by intraoperative thrombus dislodgement, except for two patients with sub-filter thrombosis. All procedures were performed using an inguinal incision to expose the deep femoral vein, ligating the major branches and dissecting the deep femoral vein. 5 patients with fresh thrombosis were embolized proximally with a 7F double-lumen Forgarty embolization balloon catheter guided by a mudskipper guidewire under DSA surveillance. The distal end of the incision was taken to elevate and squeeze the affected limb to remove the thrombus, and the deep femoral vein and saphenous vein were satisfactorily returned after releasing the distal blocking clamp. The patency of the common iliofemoral vein was confirmed by intraoperative angiography. The incision was closed after confirming the restoration of its normal blood flow. In one 87-year-old patient, the deep vein at the intraoperative incision was damaged beyond repair due to the thin wall of the vein, and the valve was preserved and then the section of the deep vein was removed and replaced with an artificial vessel. All patients were treated with an elastic bandage for 10 d after surgery, and anticoagulation and thrombolytic drugs were given through the dorsalis pedis of the affected limb. 25 patients with fresh thrombosis secondary to stenosis or occlusion of the common iliac vein were embolized in the same way as above. However, all patients in this group had varying degrees of stenosis or occlusion of the opening of the common iliac vein or external iliac vein, which was more common on the left side due to the anatomical relationship. Interventional techniques were used in all cases to pass the guidewire catheter through the stenotic or occluded segment and were successful in all cases. The stenotic or occluded segment was then dilated by exchanging the guidewire for a plain balloon. Post-dilation imaging was performed, and the procedure could be ended if most of the normal blood flow was restored without significant retraction. Among them, 19 patients with significant elastic retraction were disposed of via incision into one vascular stent. Two patients with fresh thrombosis in the inferior vena cava and bilateral lower extremities secondary to filter placement were treated with bilateral femoral vein dissection, stripping the thrombus at the incision and then removing the thrombus through the bilateral incision simultaneously with a 7F double-lumen thrombectomy balloon catheter under the guidance of a guidewire, which must be carefully passed through the filter to reach the top of the filter under DSA surveillance. The thrombus is removed from the bilateral iliofemoral vein first, followed by the thrombus in the vena cava below the filter. The two embolization balloons are opened simultaneously in the vena cava up and down to retrieve the thrombus at the same time. The embolization balloon should be opened as close as possible to the lower edge of the filter, and the position of the filter should be monitored when the balloon is opened. The thrombus should be removed from the inferior vena cava until it is clear on imaging that the thrombus has been removed from the inferior vena cava under the filter. In both patients, the intraoperative angiogram revealed that the filter was full of thrombus, so we used a 12F long sheath to enter the filter through the guidewire, withdrew the intrathecal dilatation tube and cut the end of the sheath, and then increased the suction with an external suction device to remove part of the thrombus from the filter and restore some blood flow in the filter. In two patients, the catheter was replaced with a multiport catheter, the head end of the catheter was placed in the filter, the bilateral femoral vein incision was sutured, and the tail of the catheter was externally fixed to continue thrombolysis and anticoagulation via the catheter for 24 h. After 3 d, the catheter was reviewed on imaging and the position of the catheter was adjusted. 6 d later, the flow in the inferior vena cava and the filter was restored on imaging and the patient’s limb symptoms basically disappeared. The deep vein was completely occluded, about 4 cm in length, and the upper and lower sections of the deep vein were normal, so the diseased deep vein was removed, and the saphenous vein was replaced and reconstructed. In the other 7 cases, after vein dissection, cast thrombus stripping was performed at the incision site, and a 0.35 loach guidewire was fed through the gap between the thrombus and the vein wall at the stripping site, and the thrombus was bluntly separated from the vein wall to the inferior vena cava with a guidewire under DSA, followed by a single curved or black loach catheter with a guidewire and exchanged for a super rigid guidewire, and balloon dilation of the proximal iliofemoral vein was performed in the whole segment, and the thrombus was stripped as much as possible at the distal end of the incision, and balloon dilation of the distal end was performed under DSA. All 8 patients had old thrombosis involving the confluent part of the saphenous vein. The saphenous vein was found to be membrane-like occluded during the operation, and the saphenous vein was opened to restore normal blood flow. The proximal and distal returns of the femoral vein incision were satisfactory in all patients. The thrombosed end of the incision site was then fixed to the anterior wall of the vein and the femoral vein incision was shaped with an artificial vascular patch. Postoperative anticoagulant thrombolysis and hyperelastic stockings were performed in all 40 patients. Example 1: Diagram 1 shows occlusion of the left external iliac vein Diagram 2 old thrombus in the femoral vein Diagram 3 cut and stripped old thrombus in the femoral vein Diagram 4 blunt separation through the interstitial space into the common iliac vein Diagram 5 balloon dilatation to open the external iliac vein Diagram 6 artificial vascular patch to shape the femoral vein Example 2: Diagram 7 thrombotic occlusion of the iliofemoral vein Diagram 8 thrombus removed from the incision Diagram 9 significant stenosis of the common iliac vein at the time of thrombus removal Diagram 10 Example 3: Figure 13 Right common iliac vein filled with thrombus in the filter Figure 14 Left common iliac vein also filled with thrombus Figure 15 Bilateral simultaneous thrombus retrieval Figure 16 Thrombus blockage in the filter after thrombus retrieval Figure 17 12F long sheath pass filter Figure 18 Partial thrombus aspiration followed by imaging and tube retention Figure 19 Three days after thrombolysis, there is still some thrombus under the filter. Figure 20 Three days after adjusting the position of the tube head and continuing thrombolysis, the inferior vena cava was restored to patency. The average follow-up period was 10 months, and all patients took anticoagulation and antiplatelet drugs on time and in the right dose, and no secondary thrombosis occurred in all patients. Ultrasound confirmed the patency of blood flow, and no restenosis or secondary thrombosis occurred in any of the 19 patients with stenting. The theory that slow blood flow, vascular wall damage, and blood hypercoagulation are the three elements of venous thrombosis proposed by Virchow has been continuously supplemented and improved. It is now believed that DVT occurs due to pathological changes in the coordination between blood components, hemodynamics, and the vessel wall caused by genetic defects [1]. There are controversies about the treatment methods at home and abroad, and in China, Chen Cuiju reported that the use of intravenous ultrasound ablation of thrombus and combined intra- and extra-luminal surgery achieved significant efficacy [2]. The author believes that surgical exploration under DSA to retrieve the thrombus is more intuitive, and for patients with deep vein trunk thrombus less than 15 d, direct retrieval of the thrombus is effective, while simple interventional catheter thrombolysis or drug thrombolysis through the dorsal foot vein can improve the symptoms but not completely solve the problem. For intermediate and advanced segmental thrombosis, embolization + ball expansion + stenting + patching can be used, and stenting of the stenosis should be performed in time for patients with significant retraction after ball expansion. For patients with sub-filter secondary thrombosis, the filter is usually filled with fresh thrombus, and we have achieved satisfactory results by adopting sub-filter double balloon thrombus retrieval + large diameter sheath tube negative pressure aspiration of thrombus + indwelling multi-lateral hole catheter thrombolysis, which is worth further study and promotion. For intermediate and late stage long-segment old thrombus due to the weak elasticity of thrombus and the compensatory expansion of the vein wall, we use stripping the incision of thrombus and then enter the balloon to expand and shape from the gap between the thrombus and the vein wall. After the angioplasty to ensure the blood flow and maintain a certain perfusion pressure, we made a venous artificial blood vessel patch, and actively treated with drugs and physiotherapy after the operation to achieve significant results. In China, Chen Cuiju reported the complication of venous perforation due to DVT treated by ultrasound ablation. It was caused by improper operation and position of the ultrasound catheter [3]. Since the soft tip of the mudskipper guidewire has better compliance and support, it is relatively safe for patients with long-segment occlusion to be separated bluntly with a mudskipper guidewire under DSA. However, careful intraoperative manipulation should be performed and it should be confirmed that the guidewire has entered the inferior vena cava, and an ultra-slip catheter and a suitable balloon should be selected. Since this method is a segment-by-segment blunt separation of the original gap between the long segment of mechanized thrombus and the vein wall, the complications are theoretically less likely to occur. Because of the small number of cases of long-segment mechanized thrombosis in our group, there is a lack of statistics on complications in large cases, and the incidence of complications is currently under further observation. In conclusion, the earlier the treatment for DVT is, the better. The author believes that the range of indications for either surgery alone or intervention alone for DVT is relatively small, and both procedures have their limitations. The combination of the two techniques under DSA can be effectively integrated in the treatment method and each of them has its own advantages, so the combination of surgery and interventional treatment for patients with all stages of DVT has good results and deserves further study and promotion.