Angiosome revascularization improves limb salvage

YES: The importance of the concept is established.

An angiosome is a three-dimensional anatomic unit of tissue fed by a single-source artery. The angiosome theory was first investigated in the plastic surgical literature by Taylor in the British Journal of Plastic Surgery in 1987,¹ describing 40 angiosomes throughout the body. In the lower extremity, six distinct angiosomes have been defined; one arising from the anterior tibial artery (dorsalis pedis), two from the peroneal artery (the lateral calcaneal branch and the anterior perforating branch), and three from the posterior tibial artery (the calcaneal branch, the medial plantar branch, and the lateral plantar branch).² Indirect connections known as choke vessels exist to enhance perfusion between angiosomes.

The question arises as to whether angiosome-specific revascularization enhances the healing of ischemic tissue loss of the lower extremity. Is direct revascularization of the appropriate angiosome an important part of the planning process for such revascularization efforts? Personal experience with 60 consecutive bypasses for ischemic lower extremity wounds left little doubt that angiosome-specific revascularization enhanced healing. Direct revascularization obtained 91% healing, compared with 62% when revascularization was performed to an artery which indirectly perfused the angiosome where the wound was located.³ There was also a trend for faster healing with direct angiosome revascularization. Other investigators have reported similar findings. Kret and colleagues found similar results for bypass, reporting complete healing in 78% of 106 limbs with direct revascularization with only 46% healing after bypass resulting in indirect angiosome revascularization. These authors noted that a “significant predictor for wound healing and reduced healing time was angiosome revascularization.”⁴

Consideration of the appropriate angiosome may be even more important for endovascular techniques in determining the target artery for revascularization. Iida et al investigated 200 ischemic ulcers, showing that healing was greatly enhanced by direct revascularization of the angiosome in which the wound was located.⁵ Kabra examined a mixed cohort of bypass and endovascular procedures and documented increased healing with angiosome revascularization for both modalities in treating critical limb ischemia, therefore, advising that angiosomes should be considered whenever possible.⁶ This is also an important concept for those diabetic ulcers in need of robust perfusion for healing. Alexandrescu demonstrated improved healing for diabetic ischemic ulcers after endovascular therapy with direct angiosome revascularization, concluding, “an angiosome model of perfusion helps the treatment of diabetic foot ulcers.”⁷ The group in Helsinki documented statistically significant better healing with endovascular revascularization of the appropriate angiosome in more than 250 patients with ischemic diabetic ulcers, surmising that the angiosome model is important for ulcer healing in diabetic patients.⁸

Given the many series, from around the world, confirming the impact of direct revascularization of the appropriate angiosome for a wound or non-healing ulcer to enhance healing, the importance of this concept in planning lower extremity revascularization has been established. There are certainly many considerations in planning revascularization such as patient presentation, arterial anatomy, and conduit or device selection. However, as revascularization of the appropriate wound angiosome results in more complete and rapid healing, it is irrefutable that the angiosome concept should be a consideration in planning revascularization for healing and limb preservation.

Dr. Neville is the Sara and Arnold P. Friedman and Carol and Eugene A. Ludwig Chief of Vascular Surgery Professor, Department of Surgery, and the Director, Limb Preservation Center, George Washington University, Washington.

References

1. Br J Plast Surg. 1987 Mar;40:113-41.

2. Plast Reconstr Surg. 2006 Jun;117;261S-293S.

3. Ann Vasc Surg. 2009;23:367-73.

4. J Vasc Surg. 2014 Jan;59:121-8.

5. Endovascular Today. 2010;9;96-100.

6. J Vasc Surg. 2013 Jan;57:44-49.

7. J Endovasc Ther. 2008 Oct;15:580-83.

8. J Vasc Surg. 2013 Feb;57:427-35.

NO: Only a guide, not an absolute.

Despite an aggressive approach to revascularization, amputation rates of up to 20% can occur despite a patent bypass.¹ This has led to enthusiasm for an angiosome-based revascularization strategy for the management of ischemic foot lesions.^2-4 There is no question that clinicians would opt to revascularize a blood vessel that directly feeds an involved angiosome if the vessel is easily accessible, is of good quality, and has good run-off. The issue arises if the target vessel does not meet that criteria and the surgeon is forced to intervene on an alternative feeding vessel (indirect revascularization).

There have been several studies which compare outcomes after direct and indirect revascularization strategies and they conclude that direct revascularization has better limb salvage rates.² However, most of the studies were retrospective and details on the status and quality of the pedal arch were not consistently evaluated. Rashid et al studied the impact of direct angiosome revascularization on the healing of the foot and reported that healing and time to healing of foot tissue loss were significantly influenced by the quality of the pedal arch rather than the angiosome revascularized.³