Distal arteriovenous fistula to preserve patency in COVID-19-associated acute limb ischemia.

The purpose of this study was to report our institutional experience with patients with COVID-19 who developed acute limb ischemia during hospitalization and to determine the characteristics and clinical outcomes. Between March 2020 and January 2021, we treated 3 patients who were COVID-19-positive and developed acute limb ischemia after they received thromboprophylaxis. We performed an embolectomy by exposing the popliteal artery below the knee to treat an occlusion of the popliteal and tibial arteries. An infusion of unfractionated heparin was initiated immediately after surgery, maintaining a partial thromboplastin time ratio > 2.5 times the normal value and transferred the patients to the intensive care unit. However, after these patients developed recurrent acute limb ischemia in the same leg, we decided to perform an embolectomy of popliteal and tibial arteries at the ankle and created an arteriovenous fistula (AVF) with tibial veins using polypropylene 7-0. The first patient died from pneumonia after 3 weeks in the intensive care unit; at that time, the foot was viable with triphasic flow in the distal posterior tibial artery and the AVF was patent. The second and third patients are doing well, they can walk without any problems, and the tibial arteries and AFV were patent on duplex ultrasound after 6 months. The AVF allowed part of the flow of tibial arteries to divert into the small veins of the foot that have a low resistance to maintain patency of tibial vessels, despite a hypercoagulable state and extensive thrombotic microangiopathy in patients with COVID-19.