Dynamic Skin Perfusion Pressure: A New Measure of Assessment for Wound Healing Capacity and Alternative Angiosome in Critical Limb Ischemia

Abstract

Sir: In critical limb ischemia, circulatory assessment includes angiography, computed tomographic angiography, magnetic resonance angiography, ankle-brachial index, toe pressure, and Doppler ultrasonography, whereas wound assessment includes flat plate, magnetic resonance imaging, and the bleeding condition during débridement. Recently, we have used transcutaneous partial pressure of oxygen and/or skin perfusion pressure2,3 as objective tools to determine the skin circulation around the wound. For good wound healing, we have to identify the original angiosomes of the foot and find an alternative ischemic angiosome through arterial-to-arterial connection, because 15 percent of ischemic wounds cannot heal despite successful revascularization.1 The failure is considered to be caused by inadequate revascularization of the wound and/or inadequate wound care. Revascularization of the vessel directly supplying the ischemic angiosome is more successful than revascularization of the indirectly supplying one. We reported that skin perfusion pressure measurement would be useful for predicting wound healing in critical limb ischemia.3 We would like to propose dynamic skin perfusion pressure as a new assessment measure. We define dynamic skin perfusion pressure-1 as the measure of skin perfusion pressure when the anterior tibial artery is occluded manually; dynamic skin perfusion pressure-2 measures skin perfusion pressure when the posterior tibial artery is occluded manually (Fig. 1).Fig. 1.: The procedures of dynamic skin perfusion pressure measures. (Above) Dynamic skin perfusion pressure-1, which measures skin perfusion pressure when the anterior tibial artery is occluded manually. (Below) Dynamic skin perfusion pressure-2, which measure skin perfusion pressure when the posterior tibial artery is occluded manually.A 61-year-old man presented with gangrene (ankle-brachial index, immeasurable) on his right toes and heel at both sides (Fig. 2, above), and with diabetes mellitus. Angiography demonstrated that his right superficial femoral artery was occluded, the two tibial arteries showed chronic total occlusion, and the peroneal artery came out slowly. Skin perfusion pressure was 27 mmHg at the dorsum. We performed endovascular therapy for the superficial femoral artery with an 8.0 × 80-mm nitinol stent (Smart stent; Cordis, a Johnson & Johnson Company, Warren, N.J.) and balloon angioplasty for the anterior tibial artery. Skin perfusion pressure was slightly elevated to 31 mmHg at the dorsum and 47 mmHg at the forefoot. A dynamic skin perfusion pressure-1 measurement showed 25 mmHg at the dorsum and 39 mmHg at the forefoot. These findings demonstrated that the main flow of the sole was from the anterior tibial artery, and the angiosome of the sole was displaced to the anterior tibial artery area (i.e., his toes and medial heel might not have the capacity to heal). Thus, with additional endovascular therapy of bidirectional angioplasty,4 the posterior tibial artery was recanalized successfully from the origin to the pedal arch. Skin perfusion pressure was significantly improved to 68 mmHg at the dorsum, 66 mmHg at the forefoot, and 65 mmHg at the heel. A dynamic skin perfusion pressure-1 measurement showed 54 mmHg at the dorsum, 62 mmHg at the forefoot, and 65 mmHg at the heel. These findings demonstrated that the main flow of the sole was changed from the anterior tibial artery to the posterior tibial artery and that the angiosome of the sole was restored to its normal condition, which is originally the posterior tibial artery area. After 11 days, a modified transmetatarsal amputation5 was performed, and the wound was completely healed (Fig. 2, below). His postoperative course has not been eventful for 24 months and he has walked without the help of a stick. This modified procedure is useful for preserving the soft tissue between the metatarsal bones, including the vasculature complex with the muscles, the periostea, and the vessels except for tendons. The soft tissue can also provide cushioning during walking and preserve distal circulation after wound closure.Fig. 2.: Representative case before treatment (above) and 7 months after surgery (below).DISCLOSURE The authors have no financial interest to disclose. Hiroto Terashi, M.D., Ph.D. Department of Plastic Surgery Kobe University Hospital Kobe, Japan Takanori Iwayama, M.D. Department of Plastic Surgery National Hospital Organization Himeji Medical Center Himeji, Japan Osamu Iida, M.D. Department of Cardiovascular Division Kansai Rosai Hospital Amagasaki, Japan Ikuro Kitano, M.D., Ph.D. Yoriko Tsuji, M.D., Ph.D. Wound Healing Center/Vascular and Plastic Surgery Kobe, Japan