History and clinical findings   A 76 year-old woman with 8-year history of diabetes mellitus and hypertension was admitted with gangrene of left great toe, 3rd, 4th and 5th toes. Twenty months ago, She started to receive hemodialysis due to end-stage renal disease. She did not have any history of reactive airway disease nor bradycardia that would contraindicate the use of topical beta-blocker. The X-ray of left lower limb and foot showed calcification of left superficial femoral artery, popliteal artery, anterior tibial artery, posterior tibial artery, dorsal foot artery and digital artery, as well as osteolytic destruction at distal end of metatarsal bone, and lateral dislocation of the 4th and 5th toes. Color Doppler ultrasound of bilateral lower extremity arteries showed obvious calcification of bilateral superficial femoral arteries, thrombosis of left popliteal artery, severe stenosis of left anterior tibial artery, occlusion of left posterior tibial artery, right anterior tibial artery and posterior tibial artery. Computed tomographic angiography (CTA) of bilateral lower limb arteries revealed moderate stenosis of left superficial femoral artery, occlusion of left popliteal artery, left posterior tibial artery and dorsal pedal artery, occulusion of right posterior tibial artery, but right dorsal pedal artery was visible.

  Diagnosis, treatment and follow-up  Diagnosis of diabetic foot (left, grade 4) and diabetic lower extremity arterial occlusion (left, stage 4) was made. Based on multidisciplinary team (MDT) discussion, the patient was unable to undergo vascular bypass surgery, and left lower extermity amputation also was not suitable because of right atrial thrombosis. Therefore, conservative treatment was recommended. The specific scheme used clopidogrel for antiplatelet agglutination, Low Molecular Weight Heparin (Clexane) and warfarin for anticoagulation, lipo-alprostadil for vasodilation, as well as local debridement and ultrasonic debridement. The treatments were given for up to 9 weeks, but with no significant clinical response. So the patient was treated with vacuum-assisted closure and autologous platelet-rich gel therapy for the next 7 weeks, then applied with 1 drop of timolol maleate 0.5% ophthalmic solution per cm² wound area every other day for another 6 weeks, the wound rapidly healed and re-epithelialized basically. The follow-up for 5 weeks showed that the wound healed completely without any discomfort. No side effect was found.