Oxygen Saturation Increase in Ischemic Wound Tissues after Direct and Indirect Revascularization

BACKGROUND

The primary approach for treating ischemic wounds is restoring oxygen supply to the ischemic region. While direct angiosomal revascularization is often associated with better post-operative wound healing and limb salvage, its superiority over non-angiosomal revascularization remains controversial. This study aimed to compare intraoperative tissue oxygen saturation changes in ischemic zones following either direct or indirect revascularization in below-the-knee arteries.

METHODS

This prospective observational study included patients undergoing direct and indirect below-the-knee endovascular revascularizations. Assignment to the groups was not randomized. Near-infrared spectroscopy was used to monitor rSO2 changes near the ischemic wounds intraoperatively. The changes were compared between the groups.

RESULTS

15 patients (50%) underwent direct angiosomal revascularization, while an equal number of patients underwent indirect revascularization. Overall, a statistically significant increase in regional oxygen saturation was observed after revascularization (p = 0.001). No statistically significant difference was found between the direct and indirect revascularization groups (p = 0.619).

CONCLUSIONS

This study revealed a minor difference in the oxygen saturation increase between the angiosomal and non-angiosomal revascularization groups. Such a finding indicates that the clinical significance of angiosomal revascularization is negligible and might be concealed by confounding factors, such as the vessel diameter and outflow impact on the restenosis rate.

Success of transmetatarsal amputation for limb salvage in patients with peripheral artery disease

Limb salvage is a difficult path for patients to travel as there is no guarantee of the outcome, often the major factor is perfusion. For patients who underwent transmetatarsal amputation (TMA), success rate is crucial as the next option is most likely a major amputation. We performed a 10 years (2010-2020) retrospective review of patients that underwent a TMA and had an angiogram or computed tomography angiography (CTA) perioperatively at the Dallas VA Medical Center. Failure after TMA was defined as a patient requiring a proximal amputation within 1 year. There were 125 TMAs performed between 2010 and 2020 at the institution. Forty-four (35.2%) patients had an angiogram/CTA peri-operative and met the inclusion criteria. Seventeen subjects (38.6%) had a higher level of amputation. Of the 17 failures, 2 (11.8%) patients had no patent vessel runoff to the foot, 9 (52.9%) had one vessel, 4 (23.5%) had two vessels, and 2 (11.8%) had three vessels runoff. One vessel runoff to the foot yielded a high rate of poor outcomes (56.3%) defined as a higher level of amputation. Two or more vessels runoff to the foot had over 75% success of limb salvage with a TMA.

An angiosome-centred approach for TcpO2 electrode positioning

Background: The latest guidelines propose a TcpO2 value of 30 mmHg to help to confirm the diagnosis of chronic limb threatening ischemia. However, placement of electrodes is not standardised. The relevance of an "angiosome-centred" approach for TcpO2 electrode positioning has never been evaluated. We therefore retrospectively analysed our TcpO2 results to study the impact of electrode placement on the different angiosomes of the foot. Patients and methods: Patients consulting the vascular medicine department laboratory for suspicion of CLTI using TcpO2 electrodes placement on the different angiosome arteries of the foot (first inter metatarsal space, lateral edge of the foot and plantar side of the foot) were included. As the mean intra-individual variation is reported to be 8 mmHg, a variation of mean TcpO2 for the 3 locations ≤8 mmHg was considered to be not clinically significant. Results: Thirty-four patients (34 ischemic legs) were analysed. The mean TcpO2 was higher at the lateral edge of the foot (55 mmHg) and plantar side of the foot (65 mmHg) than at the first intermetatarsal space (48 mmHg). There was no clinically significant variation of mean TcpO2 according to anterior/posterior tibial artery patency and fibular artery patency. This was present when stratifying on the number of patent arteries. Conclusions: The present study suggests that multi-electrode TcpO2 is not useful to assess tissue oxygenation in the different angiosomes of the foot to guide surgical decision; first intermetatarsal electrode alone would be preferred. TcpO2 seems rather to evaluate overall tissue oxygenation of the foot. Electrode location on the plantar side of the foot may overestimate results and lead to misinterpretation.

Angiosome-guided endovascular revascularization for treatment of diabetic foot ulcers with peripheral artery disease

OBJECTIVE

Because diabetic foot ulcers (DFUs) are difficult to heal and cause huge economic losses to society, accelerating their healing has become extremely important. The purpose of this study was to evaluate the effect of revascularization based on the angiosome concept on DFU.

MATERIALS AND METHODS

Between January 2018 and July 2020, 112 consecutive legs with DFUs in 111 patients who were discharged from the vascular surgery department of our hospital were retrospectively evaluated. The legs were assigned to two groups depending on whether direct arterial flow to the foot ulcer based on the angiosome concept was achieved. Comparisons of the ulcer healing rate, mean time to ulcer healing, major amputation rate, survival rate, and major amputation-free survival rate between the angiosome direct revascularization (DR) and angiosome indirect revascularization (IR) groups were performed.

RESULTS

DR was achieved in 71 legs (63%) compared with IR in 41 legs. The ulcer healing rate (70.4% in the DR group vs. 34.1% in the IR group, P < 0.01), the mean time to ulcer healing (7.01 ± 4.26 months vs. 10.09 ± 3.24months, P < 0.01), the survival rate (90.1% vs. 53.7%, P < 0.01), and the major amputation-free survival rate (81.7% vs. 48.8%, P < 0.01) were significantly higher in the DR group than in the IR group. Undergoing DR did not significantly reduce the major amputations rate compared with IR (13.4% and 34.1%, respectively, P = 0.15), but there might be a trend. In multivariate models, DR remained a significant predictor for ulcer healing (HR, 7.07; 95% confidence interval, 6.54-7.60, P < 0.01). Opening multiple infrapopliteal arteries in the DR group compared with restoring only one infrapopliteal artery did not significantly improve the the ulcer healing rate (P = 0.59), the mean time to ulcer healing (P = 0.70), major amputation rate (P = 0.83), the survival rate (P = 0.31), and the major amputation-free survival rate(P = 0.40).

CONCLUSIONS

Attaining a direct arterial flow based on the angiosome concept may be important for ulcer healing, survival, and amputation-free survival in diabetic foot patients. Opening multiple infrapopliteal arteries in DR patients may not improve the ulcer healing, survival, major amputation or amputation-free survival compared with single DR vessel patency.

An animal experiment study on the application of indocyanine green angiography in the harvest of multi-angiosome perforator flap

Background

This study sought to explore the application value of indocyanine green angiography (ICGA) in the harvest of multi-angiosome perforator flap and the effect of low molecular weight heparin (LMWH) on the survival of postoperative flap.

Methods

Twenty-four SD male rats were selected to construct a three-angiosome perforator flap model with the unilateral iliolumbar artery perforator. They were randomly divided into two groups: the control group was injected with indocyanine green (ICG) into the femoral vein during the operation, and the fluorescence signal was collected and quantitatively analyzed using Real-Time Image Guided System to determine the intraoperative fluorescence imaging length. The experimental group was injected subcutaneously with LMWH (400 U/kg) after 0.5 h postoperatively, and the control group was injected with the same amount of normal saline. The injection was repeated at the same time each day from 0 to 7 days postoperatively. After the flap was sutured in situ, ICGA was performed at 0, 1, 3, 5, and 7 days postoperatively to observe the vascular structure of the two groups of flaps. The flap survival length of the control group was counted at 7 days postoperatively, and the correlation between the intraoperative fluorescence imaging length and the survival length at 7 days postoperatively was calculated. The proportion of distal necrosis of the flaps between the two groups was compared at 7 days postoperatively.

Results

The average length of intraoperative fluorescence imaging in the control group was 6.29±0.50 cm, and the survival length of the flap at 7 days postoperatively was 8.24±0.52 cm. The actual survival length was higher than the intraoperative fluorescence imaging length, with a ratio of 1.31±0.08. The difference was statistically significant (P<0.05). At 7 days postoperatively, the flap necrosis ratio of experimental group and control group were 10.92%±1.30% and 19.11%±1.19%, and the flap necrosis ratio of experimental group was lower than that of control group (P<0.001).

Conclusions

ICGA can locate the position of perforator, and can be used to predict and observe the length of distal survival of multi-angiosome perforator flap postoperatively. LMWH can promote the distal survival of flap and reduce flap necrosis.

Propensity-matched analysis does not support angiosome-guided revascularization of multilevel peripheral artery disease (PAD)

BACKGROUND

This retrospective comparative cohort study evaluated the clinical outcome of angiosome-guided endovascular arterial reconstructions in chronic limb-threatening ischemia (CLTI) due to multilevel peripheral artery disease (PAD).

METHODS

Patients treated in an endovascular fashion for CLTI with tissue loss due to multilevel PAD were analyzed. Limbs were classified as having undergone either angiosome-guided (direct) revascularization (DR) or nonangiosomic (indirect) revascularization (IR). DR was defined as uninterrupted in-line flow to the affected angiosome, revascularization through the pedal arch was also considered direct. Groups were adjusted with propensity score (PS) matching and compared for amputation-free survival (AFS), freedom from major adverse limb events (MALE), and healing rate at 12 months.

RESULTS

A total of 174 patients (81 men, mean age 70.0 ± 10.4 y) were included. PS matching produced two groups of 55 patients each: DR (24 men, mean age 71.7 ± 10.7 y) and IR (26 men, mean age 72.0 ± 9.4 y). The matched groups had no significant differences in baseline variables. At 12 months there were no significant differences in AFS (73.2% vs 71.6%; p = 0.841), freedom from MALE (71.7% vs 66.1%; p = 0.617), and healing rate (72.7% vs 72.0%; p = 1.000) between DR and IR, respectively.

CONCLUSION

This study failed to support the use of angiosome concept in CLTI due to multilevel disease.

Evaluation of Peripheral Perfusion in the Presence of Plantar Heel Ulcerations Status After Transmetatarsal Amputation With Achilles Tendon Lengthening

The objective of this study is to evaluate peripheral perfusion in patients who developed plantar heel ulcerations status after transmetatarsal amputation and Achilles tendon lengthening. Peripheral perfusion was assessed via contrast angiography of the 3 crural vessels (anterior tibial, posterior tibial, and peroneal arteries), as well as intact heel blush and plantar arch. The secondary objective is to correlate the arterial flow to time to develop heel ulceration and incidence of minor and major lower-extremity amputation. Diagnostic angiography without intervention was performed on 40% of patients (4/10), and interventional angiography was performed on 60% of patients (6/10). In-line flow was present in 0% (0/10) of the peroneal arteries, 60% (6/10) of the anterior tibial arteries, and 70% (7/10) of the posterior tibial arteries. Heel angiographic contrast blush was present in 60% (6/10), and intact plantar arch was present in 60% (6/10). Patients developed heel ulcerations at a mean time of 7.6 months (range 0.7 to 41.2) postoperatively. The incidence of major lower-extremity amputation was 30% (3/10), with a mean time of 5.2 months (range 3.5 to 8.3) from time of heel wound development. No amputation occurred in 6 patients (60%). Among them, intact anterior tibial inline arterial flow was present in 3, intact posterior tibial inline arterial flow was present in 6, and heel blush was present in 5. Our results demonstrate that an open calcaneal branch of the posterior tibial artery is sufficient to heal plantar heel ulcerations to potentially increase rates of limb salvage.

Plantar thermography predicts freedom from major amputation after endovascular therapy in critical limb ischemic patients

Although plantar thermography can evaluate the immediate perfusion result after an endovascular therapy (EVT) has been performed, a relevant wound outcome study is still lacking.This study was to investigate whether angiosome-based plantar thermography could predict wound healing and freedom from major amputation after EVT in patients with critical limb ischemia (CLI).All 124 patients with CLI (Rutherford category 5 and 6) who underwent EVT from January 2017 to February 2019 were prospectively enrolled. All patients received thermography both before and after EVT. Both wound healing and freedom from major amputation at the 6-month follow-up period were recorded. There were 61 patients in the healing group and 63 patients in the non-healing group, whereas the major amputation total was 14 patients. The mean pre- and post-EVT temperature of the foot was significantly higher in the healing group than in the non-healing group (30.78 °C vs 29.42 °C, P = .015; and 32.34 °C vs 30.96 °C, P = .004, respectively). DIFF2 was significantly lower in the non-healing group (-1.38 vs -0.90, P = .009). DIFF1 and DIFF2 were significantly lower in the amputation group (-1.85 °C vs -1.11 °C, P = .026; and -1.82 °C vs -1.08 °C, P = .004). Multivariate analysis showed that DIFF2 stood out as an independent predictor for freedom from major amputation (hazard ratio 0.51, P = .045). Receiver operating characteristic curve analysis showed a DIFF2 cut-off value of -1.30 °C, which best predicts freedom from major amputation.Plantar thermography is associated with wound healing and helps predict freedom from major amputation in CLI patients undergoing EVT.

Changes in Skin Perfusion Pressure After Endovascular Treatment for Chronic Limb-Threatening Ischemia

PURPOSE

To assess skin perfusion pressure (SPP) changes after endovascular treatment (EVT) of patients with chronic limb-threatening ischemia (CLTI) and to explore preoperative factors that affect SPP changes.

MATERIALS AND METHODS

This prospective, multicenter study recruited 147 patients (mean age 74 years; 99 men) with ischemic wounds at 6 vascular centers in Japan between July 2017 and December 2018. Over half of the patients (92, 63%) were diabetic, and 76 (52%) required dialysis. Sixty-four patients (43%) had WIfI (wound, ischemia, foot infection) wound grades of 2 or 3; 59 (40%) had foot infections. SPP was measured before and 1, 2, 7, and 30 days after EVT to establish inline flow to the ischemic foot based on the angiosome concept when feasible. The anterior and posterior tibial arteries and the peroneal artery were revascularized in 66 (45%), 50 (34%), and 30 (21%) patients, respectively.

RESULTS

Both the dorsal and plantar SPPs at 1 or 2 days post-EVT were significantly higher than those at baseline (p<0.001), and both SPPs increased further at 1 month compared with those at 1 (p=0.001) or 2 days (p=0.006) post-EVT. SPP increases occurred on the dorsal and plantar surfaces of the foot regardless of the vessel revascularized. The SPP increase at 1 month after EVT was significantly lower in patients with foot infections than that in those without foot infections (p=0.003). Age, sex, diabetes, dialysis, wound severity, and direct revascularization did not affect the pattern of SPP change.

CONCLUSION

The SPP increased continuously up to 1 month after EVT, though the increase was smaller in patients with wound infections. The SPP on the dorsal and plantar surfaces increased, regardless of the vessel revascularized, which could justify indirect revascularization when direct revascularization is technically challenging.

Angiosome～From the Standpoint of Bypass Surgery

Although several studies showed that angiosome-guided endovascular treatment improved wound healing and major amputation rates in patients with chronic limb-threatening ischemia (CLTI), effectiveness of the angiosome concept to the treatment of ischemic foot remains to be elucidated, especially in bypass surgery. Arterial anatomy of the foot and ankle shows that there are multiple supplementary circulation including arterial–arterial connections and choke nexus, which indicates angiosome concept may carry limited importance in bypass surgery for CLTI. On the other hand, patients with diabetes or renal dysfunction have partial occlusion of arterial–arterial connections and, therefore, quite a few patients with CLTI in Japan may present with limited but impaired supplementary circulation around the ankle. This article reviews the arterial anatomy and circulation of the foot and ankle and discusses availability and limitations of angiosome-guided bypass surgery.

[Phenomenon of unstable tcpO2 level in transcutaneous oximetry in patients with diabetes mellitus]

The back of the foot is a standard region for measuring transcutaneous oxygen tension (tcpO2) with a reliably determined threshold of ischaemia, but such measurement reflects blood supply of only a portion of angiosomes of the foot. Determining the reference values of tcpO2 in other regions of the lower extremity is of current importance. However, measuring the tcpO2 level on the plantar surface and in some other regions not uncommonly reveal a phenomenon of its steady decrease instead of formation of a plateau. The purpose of the present study was to analyse the frequency of the phenomenon of a steady decrease in ptcO2 level while performing transcutaneous oximetry in various zones of the lower extremity. We retrospectively analysed the results of a total of 160 measurements of tcpO2 in 35 patients with diabetes mellitus. The patients' mean age amounted to 68 (47-87) years, with the duration of diabetes mellitus averaging 14 (1-24) years. The male-to-female ratio was 60:40. Seventy-seven percent of patients had foot ulcers/wounds, 34% of patients had a history of previously endured revascularization. The examination was carried out in the dorsal, plantar, medial plantar regions of the foot, on the medial surface of the crus and in the subclavian region, using the TCM 400 monitoring device (Radiometer, Denmark). The measurements were performed by an experienced operator in strict accordance with the manufacturer's recommendations. We evaluated the average value of tcpO2 between the 15th and 19th minutes of measurement and the peculiarities of the tpcO2 curve (plateau/increase/decrease of the value) within this time interval. The mean tcpO2 value in the medial plantar region was significantly higher than that on the back of the foot: 34 (3-70) versus 22 (1-59) mm Hg, p=0.003. A portion of measurements demonstrated a steady decrease in the tpcO2 during the measurement up to the 40th minute. Complying with the stable plateau phase criteria we had developed were 92% of measurements in the subclavian region, 100% - in the middle third of the crus, 76% - on the back of the foot, 77% - in the medial plantar region and 43% - on the plantar surface of the foot. CONCLUSIONS: 1) the revealed phenomenon of a steady decrease of tcpO2 in some patients needs to be taken into consideration in clinical practice and deserves further study; 2) the nature of this phenomenon is unclear, with a possible effect of skin creams on the results of the measurements; 3) it is advisable to include into the functions of the devices for transcutaneous oximetry an algorithm for confirmation of the true phase of the plateau and calculation of the mean tcpO2 value for a chosen period; 4) despite the need for measurement of tcpO2 in the 'alternative zones' it is necessary to thoroughly study the reliability of the data in these zones and to determine the normal values of the parameter separately for each of them.

SPECT/CT Imaging: A Noninvasive Approach for Evaluating Serial Changes in Angiosome Foot Perfusion in Critical Limb Ischemia

Objective: To investigate the feasibility of serial radiotracer-based imaging as a noninvasive approach for quantifying volumetric changes in microvascular perfusion within angiosomes of the foot following lower extremity revascularization in the setting of critical limb ischemia (CLI).

Approach: A CLI patient with a nonhealing foot ulcer underwent single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging of the feet before and after balloon angioplasty of the superficial femoral artery (SFA) and popliteal artery. SPECT/CT imaging was used to evaluate serial changes in angiosome perfusion, which was compared to quantitative changes in peripheral vascular anatomy and hemodynamics, as assessed by standard clinical tools that included digital subtraction angiography (DSA), ankle-brachial index (ABI), and toe-brachial index (TBI).

Results: Following revascularization, upstream quantitative improvements in stenosis of the SFA (pre: 35.4% to post: 11.9%) and popliteal artery (pre: 59.1% to post: 21.7%) shown by DSA were associated with downstream angiosome-dependent improvements in SPECT microvascular foot perfusion that ranged from 2% to 16%. ABI measurement was not possible due to extensive arterial calcification, while TBI values decreased from 0.26 to 0.16 following revascularization.

Innovation: This is the first study to demonstrate the feasibility of assessing noninvasive volumetric changes in angiosome foot perfusion in response to lower extremity revascularization in a patient with CLI by utilizing radiotracer-based imaging.

Conclusion: SPECT/CT imaging allows for quantification of serial perfusion changes within angiosomes containing nonhealing ulcers and provides physiological assessment that is complementary to conventional anatomical (DSA) and hemodynamic (ABI/TBI) measures in the evaluation of lower extremity revascularization.

A New Approach to Surgical Management of Tibial Plateau Fractures

Tibial plateau fractures (TPFs) are challenging, requiring complex open reduction and internal fixation (ORIF) and are often associated with complications including surgical site infections (SSIs). In 2007, we introduced a novel management protocol to treat TPFs which consisted of an angiosome- or perforator-sparing (APS) anterolateral approach followed by unrestricted weight bearing and range of motion. The primary aim of this retrospective study was to investigate complication rates and patient outcomes associated with our new management protocol. In total, 79 TPFs treated between 2004 and 2007 through a classic anterolateral surgical approach formed the "Classic Group"; while 66 TPFS treated between 2007 and 2013 formed the "APS Group". Fracture reduction, maintenance of reduction and patient-reported outcomes were assessed. There was a clinically important improvement in the infection incidence with the APS (1.5%) versus the Classic technique (7.6%) (1/66 versus 2/79 for superficial infections; 0/66 versus 4/79 for deep infections). Despite a more aggressive rehabilitation, there was no difference in the fracture reduction over time or the functional outcomes between both groups (p > 0.05). The APS anterolateral approach improved the rate of SSIs after TPFs without compromising fracture reduction and stabilisation. We continue to use this new management approach and early unrestricted weight bearing when treating amenable TPFs.

Infrared Thermography and Vascular Disorders in Diabetic Feet

AIM

Diabetes mellitus (DM) and related foot complications constitute a growing healthcare burden. Diabetes mellitus is associated with lower-limb amputation, but diabetic foot assessment is challenging. Here, we evaluated a novel noninvasive diagnostic method-infrared thermography (IRT) -assessing its diagnostic potential compared to conventional noninvasive measurements.

METHODS

This study included patients with DM (n = 118) and healthy controls (n = 93). All participants underwent ankle brachial index and toe pressure (TP) measurements, and IRT using a standardized protocol with temperature measurement at five foot areas.

RESULTS

Compared to controls, patients with DM generally had warmer feet and exhibited a significantly greater temperature difference between feet (P < .001). Mean temperatures were highest in patients with DM with neuroischemia, followed by neuropathy. Patients with DM with angiopathy showed the lowest mean temperature-similar to controls and noncomplicated diabetics. Mean temperatures at all measurement sites were significantly higher with abnormal TP (<50 mmHg) than normal TP (≥50 mmHg) (P < .001). Infrared thermography revealed differences between angiosome areas, subclinical infections, and plantar high-pressure areas.

CONCLUSION

Infrared thermography revealed local temperature differences in high-risk diabetic feet. Normal skin surface temperature varies between individuals, but in combination with other tools, IRT might be useful in clinical screening.

CLINICALTRIALS ID

14212016.

Healing of Diabetic Neuroischemic Foot Wounds With vs Without Wound-Targeted Revascularization: Preliminary Observations From an 8-Year Prospective Dual-Center Registry

Purpose: To assess the clinical efficacy of endovascular angiosome-oriented wound-targeted revascularization (WTR) vs indirect (wound-indifferent) revascularization (IR) in diabetic patients with neuroischemic foot ulcers. Materials and Methods: Between April 2009 and July 2017, 167 diabetic patients (mean age 72.8 years; 137 men) with chronic limb-threatening ischemia (Rutherford category 5) and foot wounds (Wagner 2-4) in 194 limbs were prospectively registered and scheduled for primary infragenicular endovascular treatment. Specific angiosome source artery reperfusion sustained by patent foot arches or arterial-arterial connections was attempted initially. If this approach failed, topographic revascularization via available collaterals (WTRc) and IR were sequentially attempted. Results: Reperfusion was successful in 176 (91%) of 194 limbs (113 with WTR, 28 with WTRc, and 35 with IR); the global angiosome-oriented technical success (WTR and WTRc) was 73% (141/194). The mean follow-up was 10.9±0.7 months (range 3-12.5). Over 1 year, 102 (58%) of the 176 successfully treated limbs experienced wound healing [79/113 (70%) in the WTR group, 15/28 (54%) in the WTRc group, and 7/35 (20%) in the IR group; p=0.011]. The mean time to healing was 6.8±0.4 months in the WTR group, 7.9±0.6 months in the WTRc group, and 9.8±0.7 months in the IR group (p=0.001). Relapses were noted in 18 (16%) WTR limbs, 5 (18%) WTRc limbs, and 6 (17%) IR limbs. Comparison between WTR and IR and WTRc vs IR showed improved cicatrization in the angiosome-oriented groups (p<0.05). Major adverse limb events (MALE) and limb salvage were different between WTR and WTRc and between WTR and IR groups (p<0.05), while WTRc vs IR was not. Amputation-free survival was not influenced by the revascularization strategy (p=0.093). Conclusion: Wound healing in diabetic patients with chronic limb-threatening ischemia appeared to be improved by intentional wound-targeted revascularization, but no uniform benefit concerning MALE or limb preservation was observed. IR still represents an alternative for limb salvage in cases in which angiosome-guided revascularization fails.

Angiosome and Tissue Healing

For the treatment of patients with critical limb ischemia (CLI), the angiosome concept is essential in revascularization and wound treatment. In this article, we describe how we use the angiosome concept for surgically treating CLI wounds and review some essential reports. For wounds in patients with CLI to heal, both successful revascularization and wound management are crucial. In order to preserve the blood supply as much as possible intraoperatively, surgeons should always consider the angiosome concept.

Pilot study on the use of infrared thermal imaging to predict infrainguinal bypass outcome in the immediate post-operative period

Objectives

Early bedside post-operative monitoring of infrainguinal bypass surgery is currently based on subjective clinical findings and handheld Doppler signals. Infrared thermal imaging is an objective and reproducible technique that has been proven to be a reliable and accurate method to measure skin temperature. The aim of this prospective study was to assess infrared thermal imaging as a predicting tool of bypass graft outcome in the immediate post-operative period and assess the angiosome concept.

Methods

This was a prospective cohort study of 25 patients undergoing infrainguinal bypass. Demographic and clinical data were prospectively collected and included gender, age, co-morbidities, pre- and post-operative ankle brachial pressure indices, surgery undertaken and patency of run-off vessels. Infrared thermal imaging was undertaken pre- and post-operatively to assess thermal changes to the feet following revascularisation.

Results

We found that an increase in temperature from pre- to post-operative was significantly associated with bypass patency. An increase in temperature was found to have a positive predictive value of 75%, a negative predictive value of 100%, a sensitivity of 100% and specificity of 89% for predicting graft patency.

Conclusions

Infrared thermal imaging can be used to measure temperature related changes of the microcirculation post-operatively and predict bypass outcomes in the immediate post-operative period.

Evaluation of angiosome-targeted infrapopliteal endovascular revascularization in critical diabetic limb ischemia

Objective To evaluate the rates of wound healing and limb preservation following angiosome-targeted infrapopliteal endovascular revascularization in the treatment of diabetic limb ischemia. Methods We performed a retrospective analysis of data gathered from 102 infrapopliteal angioplasty cases (60 males and 42 females; mean age, 72 ± 11 years) with Fontaine IV ischemia (ankle-brachial index, ABI: 0.16 ± 0.06). Forty-seven angioplasties were performed based on the angiosome concept (direct revascularization, DR), while 55 did not incorporate the angiosome concept (indirect revascularization, IR). The curative effects of angioplasty were assessed by postoperative determinations of ABI performed every 3 months during clinical follow-up visits conducted to assess healing of the ischemic wound. Amputation and death events were recorded throughout the study. Results All 102 patients were successfully revascularized without complications, and during a mean follow-up period of 18 ± 11 months, the mean postoperative ABI improved to 0.84 ± 0.10. The postoperative 6 and 12 month healing rates in the DR group were 85.1% and 93.5%, respectively, while the limb-salvage rates were 100% and 93.5%, respectively. The postoperative 6 and 12 month healing rates in the IR group were 60% and 76.4%, respectively, while the limb-salvage rates were 90.1%, and 85.5%, respectively. Conclusion Angiosome-based Infrapopliteal angioplasty was associated with better wound healing and higher rates of limb salvage in cases of critical diabetic foot ischemia. Revascularization should be provided to patients who have undergone indirect perfusion of the ischemic angiosome, as acceptable rates of limb salvage are obtained.

The thermoregulation of healthy individuals, overweight-obese, and diabetic from the plantar skin thermogram: a clue to predict the diabetic foot

Background: Thermoregulation is a complex autonomic process to keep or to dissipate heat in the human body.

Methods: In this work, by means of the thermogram of the plantar skin, the thermoregulation of healthy individuals, overweight–obese, and diabetic is discussed.

Results: The thermograms of the plantar skin, for the healthy individuals, are: (1) symmetrical, the temperature distribution of the right foot being a mirror image of that of the left foot ; (2) the thermograms of women, on average, are 3°C colder than those of the men; and (3) the temperature distributions decrease distally from the medial longitudinal arch. The plantar skin thermograms of overweight–obese individuals show: (1) increased average temperature of both feet and for both genders; (2) no symmetry between the left and right feet thermograms; and (3) the temperature distribution is still decreasing from the medial longitudinal arch to the periphery of the foot. However, the standard deviation, for each averaged temperature of the angiosomes, shows greater uncertainty. Most thermograms of diabetic individuals show temperature increase on the plantar skin, and are mostly symmetric between left and right feet.

Conclusions: An asymmetric thermogram of the plantar skin of diabetic individuals, where one foot is hotter than the other, may mean that the coldest foot is losing the capacity to communicate properly with the central nervous system and/or that vasoconstriction/vasodilatation is having problems in regulating the passing of blood through the vessels. Thus, the asymmetric thermograms of diabetic patients, and particularly those coldest regions of foot are of interest, because of the reduction of the local autonomic sensing and the lack of achieving properly the passing of the blood.

[Revelation of angiosome theory in the study of meridian point structure]

Meridian point and angiosome are the concepts in two different medical systems with a thousand year in between. In comparison between the angiosome concept and the meridian point structure characteristics in Huangdi Neijing (Yellow Emperor's Internal Classic), it is found that angiosome and meridian point are distri-buted in the head, face, trunk and four limbs. Both of them are the complex tissues of stereostructure. The essential structure of them is the vessel for blood circulation and the relevant vascular grades are of equity relationship. Both meridian point and angiosome are distributed segmentally and the number of perforator vessels is very near to that of meridian points. It is indicated on the basis of analysis that both of them are of high similarity in terms of human body structure and it is further discovered that the study achievement on angiosome not only benefits the understanding of traditional literature of meridian point, but also contributes to the deep research on the structural morphology of meridian point in terms of modern science and technology.

The Angiosome Concept Evaluated on the Basis of Microperfusion in Critical Limb Ischemia Patients-an Oxygen to See Guided Study

OBJECTIVES

Aim of this clinical study was to evaluate the angiosome concept with regard to the microcirculation of the foot in patients with CLI and to evaluate its relevance by means of combined laser Doppler flowmetrie and white-light tissue spectrophotometry.

METHODS

Twenty-eight patients who underwent leg revascularization in the stage of CLI were prospectively examined. The microperfusion was assessed by light guided spectrophotometry. The measuring points were set according to the angiosome concept into direct and indirect revascularized areas of the foot. Investigations were performed pre and postinterventionally and after 4 and 12 weeks in baseline-position as well as in an elevated position of the leg.

RESULTS

Microcirculation parameters (oxygen saturation, blood flow, velocity) of the revascularized leg showed a significant increase in elevation and baseline position compared to the preoperative values in most analyses. No significant differences between the direct and indirect revascularized angiosome were apparent.

CONCLUSION

The light-guided spectrophotometry measurement proved to be feasible in terms of measuring changes in the microcirculation after leg revascularization. However, our data do not support the value of the "angiosome concept" concerning the individual changes in microperfusion of the foot in patients with CLI.

Oximetric angiosome imaging in diabetic feet

PURPOSE

To develop a noncontrast oximetric angiosome imaging approach to assess skeletal muscle oxygenation in diabetic feet.

MATERIALS AND METHODS

In four healthy and five subjects with diabetes, the feasibility of foot oximetry was examined using a 3T clinical magnetic resonance imaging (MRI) scanner. The subjects' feet were scanned at rest and during a toe-flexion isometric exercise. The oxygen extraction fraction of skeletal muscle was measured using a susceptibility-based MRI method. Our newly developed MR foot oximetric angiosome model was compared with the traditional angiosome model in the assessment of the distribution of oxygen extraction fraction.

RESULTS

Using the traditional angiosome during the toe-flexion exercise, the oxygen extraction fraction in the medial foot of healthy subjects increased (4.9 ± 3%) and decreased (-2.7 ± 4.4%) in subjects with diabetes (difference = 7.6%; 95% confidence interval = -13.7 ± 1.4; P = 0.02). Using the oximetric angiosome, the percent difference in the areas of oxygen extraction fraction within the 0.7-1.0 range (expected oxygen extraction fraction during exercise) between rest and exercise was higher in healthy subjects (8 ± 4%) than in subjects with diabetes (4 ± 4%; P = 0.02).

CONCLUSION

This study demonstrates the feasibility of measuring skeletal muscle oxygen extraction fraction in the foot muscle during a toe-flexion isometric exercise. Instead of assessing oxygen extraction fraction in a foot muscle region linked to a supplying artery (traditional angiosome), the foot oximetric angiosome model assesses oxygen extraction fraction by its different levels in all foot muscle regions and thus may be more appropriate for assessing local ischemia in ulcerated diabetic feet. J. Magn. Reson. Imaging 2016. J. MAGN. RESON. IMAGING 2016;44:940-946.

Clinical Implications of Additional Pedal Artery Angioplasty in Critical Limb Ischemia Patients With Infrapopliteal and Pedal Artery Disease

PURPOSE

To evaluate the clinical implications of additional pedal artery angioplasty (PAA) for patients with critical limb ischemia (CLI).

METHODS

Twenty-nine patients (mean age 77.8±8.6 years; 21 men) with CLI (32 limbs) presenting with de novo infrapopliteal and pedal artery (Kawarada type 2/3) disease were reviewed. The need for PAA was based on the existence of sufficient wound blush (WB) around the target wounds after conventional above-the-ankle revascularization. Fourteen patients with insufficient WB in 14 limbs received additional PAA, while 15 patients with sufficient WB in 18 limbs did not. The groups were compared for overall survival, limb salvage, and amputation-free survival within 1 year after the procedure. The wound healing rate, time to wound healing, and freedom from reintervention rate were also evaluated.

RESULT

The success rate of additional PAA was 93% (13/14). All limbs with successful PAA achieved sufficient WB (13/13). Despite insufficient WB before the additional PAA, overall survival (86% vs 73%, p=0.350), limb salvage (93% vs 83%, p=0.400), amputation-free survival (79% vs 53%, p=0.102), and freedom from reintervention (64% vs 73%, p=0.668) rates were similar in both groups. Furthermore, the wound healing rate (93% vs 60%, p=0.05) was higher and time to wound healing (86.0±18.7 vs 152.0±60.2 days, p=0.05) was shorter in the patients who received PAA.

CONCLUSION

Additional PAA might improve the WB and clinical outcomes (especially speed and extent of wound healing) in patients with CLI attributed to infrapopliteal and pedal artery disease.

Cutting Balloon Angioplasty in the Treatment of Short Infrapopliteal Bifurcation Disease

PURPOSE

To evaluate the safety, feasibility, and effectiveness of cutting balloon angioplasty in the management of infrapopliteal bifurcation disease.

METHODS

Between November 2010 and March 2013, 23 patients (mean age 69.6±9.01 years, range 56-89; 16 men) suffering from critical limb ischemia were treated using cutting balloon angioplasty (single cutting balloon, T-shaped double cutting balloon, or double kissing cutting balloon technique) for 47 infrapopliteal artery bifurcation lesions (16 popliteal bifurcation and 9 tibioperoneal bifurcation) in 25 limbs. Follow-up consisted of clinical examination and duplex ultrasonography at 1 month and every 3 months thereafter.

RESULTS

All treatments were technically successful. No 30-day death or adverse events needing treatment were registered. No flow-limiting dissection was observed, so no stent implantation was necessary. The mean postprocedure minimum lumen diameter and acute gain were 0.28±0.04 and 0.20±0.06 cm, respectively, with a residual stenosis of 0.04±0.02 cm. Primary and secondary patency rates were estimated as 89.3% and 93.5% at 6 months and 77.7% and 88.8% at 12 months, respectively; 1-year primary and secondary patency rates of the treated bifurcation were 74.2% and 87.0%, respectively. The survival rate estimated by Kaplan-Meier analysis was 82.5% at 1 year.

CONCLUSION

Cutting balloon angioplasty seems to be a safe and effective tool in the routine treatment of short/ostial infrapopliteal bifurcation lesions, avoiding procedure-related complications, overcoming the limitations of conventional angioplasty, and improving the outcome of catheter-based therapy.

Impact of angiosome-oriented revascularization on clinical outcomes in critical limb ischemia patients without concurrent wound infection and diabetes

PURPOSE

To investigate the impact of angiosome-oriented revascularization on clinical outcomes in critical limb ischemia (CLI) patients excluding those with both diabetes and wound infection.

METHODS

Using a retrospective multicenter database, a propensity score matching analysis was performed of 539 consecutive CLI patients (375 men; mean age 71±11 years) without concurrent wound infection and diabetes who underwent balloon angioplasty of isolated infrapopliteal lesions. Propensity score matching produced 2 groups of 182 patients each who underwent angiosome-oriented direct revascularization (123 men; mean age 72±11 years) or indirect revascularization (125 men; mean age 72±11 years). The groups were compared for wound healing rate, freedom from major adverse limb events (MALE), and amputation-free survival (AFS).

RESULTS

In the overall population, indirect revascularization was performed in 36.6% (n=197). In the propensity matching analysis, the complete wound healing rate at 12 months was higher in the direct group than the indirect revascularization patients (75% vs. 64%, p=0.01), while freedom from MALE (p=0.99) and AFS (p=0.17) were not significantly different at up to 24 months. In multivariate analysis, indirect revascularization had an independent negative impact on wound healing (adjusted hazard ratio 0.7, p=0.008).

CONCLUSION

After propensity matching analysis for CLI patients other than those with both diabetes and wound infection, the wound healing rate was higher after direct revascularization than after indirect revascularization, whereas MALE and AFS were not significantly different.

Angiosomes: how do they affect my treatment?

The number of diabetic patients is actually increasing all around the world, consequently, critical limb ischemia and ischemic diabetic foot disorders related to the presence of diabetic occlusive arterial disease will represent in the next few years a challenging issue for vascular specialists. Revascularization represents one step in the treatment for the multidisciplinary team, reestablishing an adequate blood flow to the wound area, essential for healing and avoiding major amputations. The targets of revascularization can be established to obtain a "complete" revascularization, treating all tibial and foot vessels or following the angiosome and wound-related artery model, obtaining direct blood flow for the wound. In this article, we summarize our experience in endovascular treatment of diabetic critical limb ischemia, focusing on the angiosome and wound-related artery model of revascularization and the technical challenges in treating below-the-knee and below-the-ankle vessels.

Medial and Lateral Plantar Artery Angiosome Rotational Flaps for Transmetatarsal and Lisfranc Amputation in Patients With Compromised Plantar Tissue

Traditional incision techniques for midfoot amputation might not provide immediate soft tissue coverage of the underlying metatarsal and tarsal bones in the presence of a large plantar soft tissue defect. Patients undergoing transmetatarsal and Lisfranc amputation frequently have compromised plantar tissue in association with neuropathic ulcers, forefoot gangrene, and infection, necessitating wide resection as a part of the amputation procedure. Open amputation will routinely be performed under these circumstances, although secondary healing could be compromised owing to residual bone exposure. Alternatively, the surgeon might elect to perform a more proximal lower extremity amputation, which will allow better soft tissue coverage but compromises function of the lower extremity. A third option for this challenging situation is to modify the plantar flap incision design to incorporate a medial or lateral plantar artery angiosome-based rotational flap, which will provide immediate coverage of the forefoot and midfoot soft tissue defects without excessive shortening of the bone structure. A plantar medial soft tissue defect is treated with the lateral plantar artery angiosome flap, and a plantar lateral defect is treated with the medial plantar artery angiosome flap. Medial and lateral flaps can be combined to cover a central plantar wound defect. Incorporating large rotational flaps requires knowledge of the applicable angiosome anatomy and specific modifications to incision planning and dissection techniques to ensure adequate soft tissue coverage and preservation of the blood supply to the flap. A series of 4 cases with an average follow-up duration of 5.75 years is presented to demonstrate our patient selection criteria, flap design principles, dissection pearls, and surgical staging protocol.

Rapid vs. delayed infrared responses after ischemia reveal recruitment of different vascular beds

Continuous infrared imaging revealed transient changes in forearm temperature during arterial occlusion, reperfusion, and recovery in a healthy subject group. Processing the imaging data with the k-means algorithm further revealed reactive vascular sites in the skin with rapid or delayed temperature amplification. The observed temporal and spatial diversity of blood-flow-derived forearm temperature allow consideration of thermal-imaging guided placement of skin sensors to achieve enhanced sensitivity in monitoring of skin hemodynamics.

Treating calf and pedal vessel disease: the extremes of intervention

Recent developments in catheter, balloon, and guidewire technology have increased the scope for endovascular treatments in the management of complex and challenging disease in the calf and foot. The antegrade femoral approach remains the starting point for most interventions, but there is a growing role for procedures performed from unconventional access such as the pedal arteries. This article reviews the indications for intervention, atypical access, and the choice of equipment for these extreme interventions.

Effect of single tibial artery revascularization on microcirculation in the setting of critical limb ischemia

BACKGROUND

Benefits of 2-dimensional (2D) angiosome-oriented infrapopliteal revascularization remain controversial. The aim of this retrospective study was to clarify the effect of single tibial artery revascularization on the dorsal and plantar microcirculation of critically ischemic limbs based on skin perfusion pressure (SPP).

METHODS AND RESULTS

Fifty-seven interventions that only involved either anterior tibial artery (ATA) or posterior tibial artery (PTA) revascularization were included in this study. SPP was measured on the dorsal side (theoretically ATA perfusion area) and the plantar side (theoretically PTA perfusion area) before and after the procedure. Dorsal and plantar SPP increased significantly, from 33 (IQR 23-40.5) to 52 (IQR 32.5-65) mm Hg (P<0.0001) and 31.6±16.1 to 44.8±19.2 mm Hg (P=0.001) after ATA revascularization, respectively, and from 29.3±14.0 to 42.4±19.7 mm Hg (P=0.003) and 29.3±9.8 to 43.5±15.9 mm Hg (P<0.001) after PTA revascularization, respectively. Both ATA and PTA revascularization were not associated with any significant differences in ΔSPP between the dorsal and the plantar regions of the foot. Only 64% and 58% of ATA revascularization cases showed higher post-SPP and ΔSPP on the dorsal side than on the plantar side, respectively. Also, only 47% and 40% of PTA revascularization cases showed higher post-SPP and ΔSPP on the plantar side than on the dorsal side, respectively.

CONCLUSIONS

Single tibial artery revascularization, whether of the ATA or PTA, yielded comparable improvements in microcirculation of the dorsal and plantar foot. Approximately half of the feet revascularized had a change in microcirculation that was not consistent with the 2D angiosome theory.

Endovascular techniques in limb salvage: infrapopliteal angioplasty

Critical limb ischemia (CLI) results from inadequate blood flow to supply and sustain the metabolic needs of resting muscle and tissue. Infragenicular atherosclerosis is the most common cause of CLI, and it is more likely to develop when multilevel or diffuse arterial disease coincides with compromised run-off to the foot. Reports of good technical and clinical outcomes have advanced the endovascular treatment options, which have gained a growing acceptance as the primary therapeutic strategy for CLI, especially in patients with significant risk factors for open surgical bypass. In fact, endovascular recanalization of below-the-knee arteries has proven to be feasible and safe, reduce the need for amputation, and improve wound healing. The distribution of various vascular territories or angiosomes in the foot has been recognized, and it appears advantageous to revascularize the artery supplying the territory directly associated with tissue loss. In addition, the targeted application and local delivery of drugs using drug-coated balloons (DCB) during angioplasty has the potential to improve patency rates compared to balloon angioplasty alone.

Morphological pattern classification system for plantar thermography of patients with diabetes

BACKGROUND

A plantar temperature distribution can be obtained by thermography; however, the advantage has not been effectively utilized in the past. We previously proposed a classification method based on the angiosome concept, but the method was insufficient because it was too subjective and complicated for clinicians. In this study, we propose a new classification system of plantar forepart thermographic patterns using an image segmentation technique.

METHODS

A cross-sectional observational study was conducted including 32 healthy volunteers and 129 patients with diabetes mellitus (DM). Individual thermographic variations and trends were evaluated. A comparison was conducted between the patterns obtained by our previous angiosome-based research and the patterns found by the new classification system.

RESULTS

The system objectively found wider variations of the plantar forepart thermographic patterns in the patients with DM compared with those in the control subjects. In patients with DM, the system showed that the whole-high pattern was most frequent (46%), followed by the butterfly pattern (12%). In the control group, the butterfly pattern was most frequent (44%), followed by the whole-high pattern (19%). Both ankle and toe brachial indices were higher in feet with high temperature area in the inner side of the plantar.

CONCLUSIONS

Thermographic patterns found by the new computer-based system were similar to those obtained in our previous subjective work. The classification system found forefoot-low pattern and tiptoe-low pattern objectively. The system based on infrared thermography will be a screening tool to assess circulatory status in daily foot care of patients with DM.

Endovascular treatment of critical ischemia in the diabetic foot: new thresholds, new anatomies

This review discusses the role of endovascular treatment in diabetic patients with critical limb ischemia (CLI). Angioplasty of the femoropopliteal region achieves similar technical success and limb salvage rates in diabetic and nondiabetic patients. Angioplasty in as many as possible tibial vessels is accompanied by more complete and faster ulcer healing as well as better limb salvage rates compared to isolated tibial angioplasty. Targeted revascularization of a specific vessel responsible for the perfusion of a specific ulcerated area is a promising new approach: it replaces revascularization of the angiographically easiest-to-access tibial vessel, even if this is not directly responsible for the perfusion of the ulcerated area, by revascularization of area-specific vascular territories. In conclusion, the endovascular approach shows very high efficacy in ulcer healing for diabetic patients with CLI. Larger prospective studies are now needed to estimate the long-term results of this approach.

A three-subunit latissimus dorsi muscle free flap for single-stage coverage of the hand and three adjacent fingers

A latissimus dorsi muscle flap was used to simultaneously resurface the dorsal index, middle, and ring fingers of a 10-year-old child who had sustained a severe abrasion burn from a go-kart injury. Rather than performing multiple individual flaps, or a single flap in which a secondary division procedure would have been needed, the flap was divided into three vascular territories, permitting a single-stage reconstruction. Use of this strategy minimized the need for prolonged rehabilitation, and the functional outcome was optimized.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s11552-009-9208-5) contains supplementary material, which is available to authorized users.