Choice of peroneal or dorsalis pedis artery bypass for limb salvage

miR-210: the master hypoxamir

MicroRNAs are small non-coding RNAs implicated mainly in post-transcriptional gene silencing by interacting with the untranslated region of the transcript. miR-210 represents major hypoxia-inducible miRs, also known as hypoxamirs, which is ubiquitously expressed in a wide range of cells, serving versatile functions. This review article summarizes the current progress on biogenesis of miR-210 and its physiological roles including arrest of cell proliferation, repression of mitochondrial respiration, arrest of DNA repair, vascular biology, and angiogenesis. Given the fact that miR-210 is aberrantly expressed in a number of diseases such as tumor progression, myocardial infarction and cutaneous ischemic wounds, miR-210 could serve as an excellent candidate for prognostic purposes and therapeutic intervention. With the advancement of computational prediction, high-throughput target validation methodology, sequencing, proteomic analysis, and microarray, it is anticipated that more down-stream targets of miR-210 and its associated biological consequences under hypoxia will be unveiled establishing miR-210 as a major hub in the biology of hypoxia-response.

Angiosomes and wound care in the diabetic foot

Successful foot and ankle reconstructions require a detailed knowledge of vascular anatomy. This knowledge becomes all the more important in diabetic patients because of healing complications and high incidence of peripheral vascular disease; it allows foot and ankle surgeons to design safe exposures and vascular surgeons to choose effective revascularization strategies. The angiosome concept separates the body into distinct threedimensional blocks of tissue fed by source arteries. This article focuses on the surgical implications of angiosomes of the foot and ankle and their arterial-arterial connections.

Revascularization of a specific angiosome for limb salvage: does the target artery matter?

Ischemic wounds of the lower extremity can fail to heal despite successful revascularization. The foot can be divided into six anatomic regions (angiosomes) fed by distinct source arteries arising from the posterior tibial (three), anterior tibial (one), and peroneal (two) arteries. This study investigated whether bypass to the artery directly feeding the ischemic angiosome had an impact on wound healing and limb salvage. Retrospective analysis was performed for 52 nonhealing lower extremity wounds (48 patients) requiring tibial bypass over a 2-year period. Preoperative arteriograms were reviewed to determine arterial anatomy relative to each wound's specific angiosome and bypass anatomy. Patients were divided into two groups; direct revascularization (DR, bypass to the artery directly feeding the ischemic angiosome) or indirect revascularization (IR, bypass unrelated to the ischemic angiosome). Wound outcome was analyzed with regard to the endpoints of complete healing, amputation, or death unrelated to the wound. Time to healing was also noted for healed wounds. Based on preoperative arteriography, 51% (n = 27) of the wounds received DR to the ischemic angiosome, while 49% (n = 25) underwent IR. There were no statistically significant differences in the comorbidities of the two groups. Revascularization was via tibial bypass using the saphenous vein (n = 34, 65%) or polytetrafluoroethylene with a distal vein patch (n = 18, 35%). Bypasses were performed to the anterior tibial (n = 22, 42%), posterior tibial (n = 17, 33%), or peroneal (n = 13, 25%) arteries based on the surgeon's judgment. One bypass failed in the perioperative period and was excluded from the analysis. The remaining bypasses were patent at the time of wound analysis. Due to a 17% mortality rate during follow-up, 43 wounds were available for endpoint analysis. This analysis demonstrated that 77% of wounds (n = 33) progressed to complete healing and 23% of wounds (n = 10) failed to heal with resultant amputation. In the DR group, there was 91% healing with a 9% amputation rate. In the IR group, there was 62% healing with a 38% amputation rate (p = 0.03). In those wounds that did heal, total time to healing was not significantly different--DR 162.4 days versus IR 159.8 days (p = 0.95). Revascularization plays a crucial role in the treatment of ischemic lower extremity wounds. We believe that direct revascularization of the angiosome specific to the anatomy of the wound leads to a higher rate of healing and limb salvage. Although many factors must be considered in choosing the target artery for revascularization, consideration should be given to revascularization of the artery directly feeding the ischemic angiosome.

Angiosomes of the Foot and Ankle and Clinical Implications for Limb Salvage: Reconstruction, Incisions, and Revascularization

BACKGROUND

Ian Taylor introduced the angiosome concept, separating the body into distinct three-dimensional blocks of tissue fed by source arteries. Understanding the angiosomes of the foot and ankle and the interaction among their source arteries is clinically useful in surgery of the foot and ankle, especially in the presence of peripheral vascular disease.

METHODS

In 50 cadaver dissections of the lower extremity, arteries were injected with methyl methacrylate in different colors and dissected. Preoperatively, each reconstructive patient's vascular anatomy was routinely analyzed using a Doppler instrument and the results were evaluated.

RESULTS

There are six angiosomes of the foot and ankle originating from the three main arteries and their branches to the foot and ankle. The three branches of the posterior tibial artery each supply distinct portions of the plantar foot. The two branches of the peroneal artery supply the anterolateral portion of the ankle and rear foot. The anterior tibial artery supplies the anterior ankle, and its continuation, the dorsalis pedis artery, supplies the dorsum of the foot. Blood flow to the foot and ankle is redundant, because the three major arteries feeding the foot have multiple arterial-arterial connections. By selectively performing a Doppler examination of these connections, it is possible to quickly map the existing vascular tree and the direction of flow.

CONCLUSIONS

Detailed knowledge of the vascular anatomy of the foot and ankle allows the plastic surgeon to plan vascularly sound reconstructions, the foot and ankle surgeon to design safe exposures of the underlying skeleton, and the vascular surgeon to choose the most effective revascularization for a given wound.

Bypass to plantar and tarsal arteries: An acceptable approach to limb salvage

OBJECTIVE

This study was undertaken to evaluate our experience with distal arterial bypass to the plantar artery branches and the lateral tarsal artery for ischemic limb salvage.

METHODS

This was a retrospective analysis of data prospectively entered into our vascular surgery database from January 1990 to January 2003 for all consecutive patients undergoing bypass grafting to the plantar artery branches or the lateral tarsal artery. Median follow-up was 9 months (range, 1-112 months). Demographic data, indications for surgery, outcomes, and patency were recorded, and statistical analysis was performed to assess significance.

RESULTS

Ninety-eight bypass procedures to either the medial plantar artery, lateral plantar artery, or lateral tarsal artery were performed in 90 patients. Eighty-one patients (83%) were men. Mean age was 67.5 +/- 11.6 years. Indications for operation were tissue loss in 93 patients (95%), rest pain in 3 patients (3%), and failing graft in 2 patients (2%). Eighteen patients (18%) had previously undergone vascular reconstruction, and 5 patients (5%) had undergone previous bypass to the dorsalis pedis artery. Seventy-one grafts (72%) had inflow from the popliteal artery, 25 grafts had inflow from a femoral artery or graft (26%), and 2 grafts had inflow from a tibial artery (2%). Conduits used were greater saphenous vein in 67 patients (69%), arm vein in 20 patients (20%), composite vein in 10 patients (10%), and polytetrafluoroethylene conduit in 1 patient (1%). There were 77 bypasses (79%) to plantar artery branches, and 21 bypasses (21%) to the lateral tarsal artery. Thirty-day mortality was 1% (1 of 98 procedures). Early graft failure within 30 days occurred in 11 patients (11%). In the subset of patients with a previous arterial reconstruction, there were 2 early graft failures within 30 days (11%). Both occurred in patients who had undergone previous bypass to the dorsalis pedis artery. Primary patency, secondary patency, limb salvage, and patient survival were 67%, 70%, 75%, and 91%, respectively, at 12 months, and 41%, 50%, 69%, and 63%, respectively, at 5 years, as determined from Kaplan-Meier survival curves. Greater saphenous vein grafts performed better than all other conduits, with a secondary patency rate of 82% versus 47% at 1 year (P = .009).

CONCLUSION

Inframalleolar bypass to plantar artery branches and the lateral tarsal artery, even in patients with a previously failed revascularization, can be undertaken with acceptable patency and limb salvage rates. Early graft failure, however, is higher, whereas patency and limb salvage rates are lower, compared with bypass to the dorsalis pedis artery. The use of saphenous vein as a conduit results in the best patency for plantar or lateral tarsal bypass procedures.

Medical and surgical considerations in patients with vasculitis and Raynaud's syndrome

Vascular problems in the foot are certainly common when one considers only arteriosclerosis on the macrovascular scale. The primary cause of ischemia of the foot undoubtedly is primary arteriosclerosis, whether related to smoking, diabetes, renal failure, or other causes. Vasculitis and vasospasm, in their many forms, are distinctly unusual as a cause of ischemia of the foot. These entities, nonetheless, can cause significant problems from the standpoint of symptoms and even ulceration or gangrene of the foot. This article addresses the pathophysiology of vasculitis and vasospastic problems in the foot and their management.