Surgical Options in Thrombectomy for Non-Surgeons Shouwen Wang, MD, PhD, FASDIN AKDHC Ambulatory Surgery Center Arizona Kidney Disease and Hypertension Center Phoenix, Arizona
Disclosure No relevant financial or other conflict of interests to disclose.
Objectives Discuss the indications and technical considerations of small-venotomy thrombectomy. Discuss the clinical outcomes of small-venotomy thrombectomy and the need for further surgical evaluation in selected patients.
Most AV Access Thrombectomy Can be Accomplished with Endovascular Approach Endovascular thrombectomy can be achieved with combination of balloon angioplasty, aspiration, Fogarty balloon, and thrombolytics. Mechanical devices or other tools are typically not needed. However, occasionally, thrombectomy could not be accomplished only by simple endovascular approach and may consume a lot of procedure time.
Clinical Scenarios of Difficult or Potentially Dangerous Thrombectomy Organized clots obstructing access flow. Large fistula or graft aneurysms. Mega fistulas with massive clot burden. Fistulas or grafts with unreliable outflow (occluded superficial veins at the elbow with fistula drained via perforating vein, occluded cephalic arch with collateral vein formation, grafts with retrograde basilic vein outflow). Insufficient or complex inflow anatomy. Foreign material (stents or other material) affecting access flow. Infected AV access, thrombectomy is contraindicated.
Other Options Beyond Simple Endovascular Thrombectomy Large sheath aspiration. Endovascular mechanical tools. Stent-graft exclusion of organized clots (in the noncannulation zone). Small-venotomy thrombectomy. Surgical thrombectomy and revision. Access abandonment (get a surgical opinion first).
When Small-Venotomy Thrombectomy is indicated? Limited organized clots obstructing access flow. Some fistulas with large aneurysms. Some mega fistulas with large clot burden. Fistulas with less reliable outflow but clearly known anatomy ( such as occluded superficial veins at the elbow with fistula drained via perforating vein). Small foreign material (such as retained balloon piece or sheath) affecting access flow.
When Small-Venotomy Thrombectomy is Contraindicated? Extensive organized clots obstructing access flow. Most mega fistulas with massive clot burden. Most fistulas or grafts with unreliable outflow. Large foreign material (stents or stent-grafts) affecting access flow. Infected AV access.
What is Small-Venotomy Thrombectomy? A limited small surgical procedure directly over an arteriovenous access (fistulas or grafts). The access circulation is controlled with various methods. A small incision is made through the skin, subcutaneous tissue, and the vascular wall to reach the vascular lumen. Through the small-venotomy, mechanical tools and maneuvers may be used to clear the clots out of the vascular lumen, as completely as possible. The incision is closed with sutures to restore access integrity.
How to controlled the AV Access Circulation during Thrombectomy? Inflated balloon at both access inflow and outflow. Elastic tourniquet (such as Esmarch bandage) for inflow control, avoid direct compression of clots. Manual compression of access inflow and outflow (need good assistants). Pneumatic tourniquet (especially forearm access). Cut down over inflow and outflow, use vascular clamps or vascular loops (more surgical). Combination of the above approaches.
Where to Make the Small-Venotomy? The key considerations are to assure subsequent healing and to avoid stenosis at the incision site. Close to the target clots. At a dilated access area. Avoid scarred and thinning areas. Choose a relatively health area.
Where to Make the Small-Venotomy?
How to Clear the Clots Out of the AV Access? Clear clots as complete as possible. Hemostats, forceps or other tools. Manual compression/squeeze. Vacuum suction. Fogarty balloon. Balloon catheter. May inject some contrast to visualize residual clots.
How to Close the Incision? The key considerations are to achieve secure hemostasis and to promote tissue healing. May use single layer (when incision is small) or two layer closure (when incision is larger). Continuous 4-0 Prolene for suturing the vascular wall, Continuous or intermittent 3-0 Prolene or other suture for closing the skin. May use liquid bandage and sterile strips over the incision.
Potential Complications of Small-Venotomy Thrombectomy Blood loss during the procedure. Bleeding from the venotomy post procedure. Infection or delayed healing of the incision. Outflow thromboembolism (pulmonary embolism, stroke). Arterial thromboembolism. Other complications
Who Can Safely Perform Small-Venotomy Thrombectomy? Patient safety first. Proper training and thorough understanding of the underlying pathology and the specific technical approaches are crucial. Know your limitations and know what you are doing. Interventional radiologists. Interventional nephrologists. Access surgeons.
A Typical Case of Small-Venotomy Thrombectomy
Removal of Retained Sheath Fragment
Large Burden of Organized Clots
Removal of Bare-Metal Stents in the Cannulation Zone
Removal of Stent-Graft Obstructing Access Flow and Contributing to Thrombosis
Surgical Thrombectomy and Outflow Revision Wang S, et al. Seminars in Dialysis 2013, 26:E33-E41
Clinical Outcomes of Small-Venotomy Thrombectomy Very few reports in the literature (done by non-surgeons). Joo SM, et al. J Vasc Interv Radiol 2013, 24:401-5 (25 patients, incision on dilated aneurysm, using forceps and Fogarty catheter, all successful, two major bleeding complications). (Radiologist, Korea) Ponikvar R. Ther Apher Dial 2009, 13:340-4. 128 thrombectomies in 111 patients, 91 thrombectomies with reanastomosis vs 37 thrombectomies alone, a few PTA + stenting or jump grafts, 94% immediate success, 1 year secondary patency 73% vs 54%. (nephrologist, Slovenia,) Dr. Ted Saad presented his data at a meeting a few years ago. The author s data being collected.
Why the Clinical Outcomes of Small- Venotomy Thrombectomy are Limited Unresolved underlying pathology that are inducive to thrombosis. Aneurysms with rough endoluminal surface and turbulent flow. Unreliable access outflow or limited access inflow. Hypercoagulable states. Consider surgical consultation when surgical revision or new access option need to be entertained.
Conclusions Small-venotomy thrombectomy is a useful approach for selected patients in whom simple endovascular thrombectomy is inadequate or unsafe. Thorough understanding of underlying pathology of a patient and proper execution of the technical approaches are essential to ensure success and patient safety. Small-venotomy thrombectomy may be safely performed by qualified interventionalists and may reduce prolonged thrombectomy procedure time in selected patients.
Acknowledgements The supports of the staff and colleagues of AKDHC Access Centers are greatly appreciated.