Why critical limb ischemia criteria are not applicable to diabetic foot and what the consequences are

The Effect of Revascularization on Lower Limb Circulation Parameters in Symptomatic Peripheral Arterial Disease

Background: The prevalence of peripheral arterial disease and the number of revascularization procedures performed in symptomatic patients are steadily increasing. However, uncertainties remain regarding hemodynamic monitoring after revascularization and the prediction of clinical outcomes. This study aimed to investigate hemodynamic parameters with a focus on the microvasculature. Methods: This prospective, single-center study included 29 patients (15 with intermittent claudication [IC] and 14 with chronic limb-threatening ischemia [CLTI]). Before and after the revascularization procedure, in addition to the ankle-brachial index (ABI), microperfusion parameters, including microvascular blood flow, capillary oxygen saturation (SO2), and relative hemoglobin content (rHb), were assessed with lightguide spectrophotometry combined with laser Doppler flowmetry using an oxygen-to-see (O2C) device in the horizontal and elevated leg positions. Results: At baseline, SO2 in the elevated leg position was significantly lower in patients with CLTI than in those with IC (p = 0.0189), whereas the other microcirculatory parameters and ABI values were not significantly different. Patients with diabetes mellitus had a higher flow rate than those without in the horizontal leg position (p = 0.0162) but not in the elevated leg position. After successful revascularization, the flow increased immediately and significantly in both positions, whereas SO2, rHb, and the ABI did not. Conclusions: Elevated leg SO2 was significantly lower in CLTI than in clinically compensated peripheral arterial disease, whereas microvascular flow was a suitable surrogate parameter indicating successful revascularization. In studies using surgical or interventional revascularization procedures, noninvasive hemodynamic monitoring of the microcirculation at the foot level might be beneficial.

Objective Evidence That Nerve Decompression Surgery Reduces Neuropathic DFU Recurrence Risk to Less than 5%

Significance: Despite 20 years of research and new treatment methods, diabetic foot ulcer (DFU) remains a common problem with frequent recurrences and complications. Recent Advances: There are reports that nerve decompression (ND) surgery has been observed to produce significantly fewer DFU recurrences than standard of care (SOC). The explanation of this apparent superiority has not been understood. Critical Issues: Microcirculation is understood to be involved in diabetic peripheral neuropathy (DPN) and DFU. There is an underappreciation of the participation in DPN of entrapment neuropathy (EN) due to nerve swelling and impingement in fibro-osseous tunnels. Reducing c-fiber compression in EN by ND generates recovery of subepidermal capillary flow. ND studies have found improved neuromuscular function and epidermal microcirculation phenomena, including chronic capillary ischemia (CCI) and pressure-induced vasodilatation (PIV). There is no current therapy recommended for impaired microcirculation. Clinical and animal evidence has demonstrated that release of locally compressed peripheral nerves improves the epidermal microcirculation which is under sympathetic control. Future Directions: Using epineurolysis to relieve nerve compressions is a physiology-based therapeutic intervention and provides the scientific foundation clarifying how ND reduces DFU recurrence risk. Incorporating ND with current SOC treatments could improve DFU recurrence risk, hard-to-heal ulcers, neuroischemic wounds, amputation risk, and the resulting costs to society. More studies using ND for DFU, especially evidence-based medicine Level I studies, are needed to confirm these preliminary outcomes.

Peripheral Arterial Disease and the Diabetic Foot Syndrome: Neuropathy Makes the Difference! A Narrative Review

Background: In vascular medicine, peripheral arterial disease (PAD) and diabetic foot syndrome (DFS) are often considered synonymous with respect to the need for revascularization. In PAD patients, clinical symptoms reflect the degree of atherosclerotic disease, since peripheral innervation, including pain sensation, is not usually compromised. In DFS patients, however, symptoms of relevant foot ischemia are often absent and progression of ischemia goes unnoticed owing to diabetic polyneuropathy, the loss of nociception being the main trigger for foot ulcers. This review analyzes the fundamental differences between PAD and DFS against the background of polyneuropathy. Methods: The literature research for the 2014 revision of the German evidence-based S3-PAD-guidelines was extended to 2023. Results: Vascular examination is imperative for both, PAD and DFS. Stage-dependent revascularization is of utmost importance in PAD patients, especially those suffering from critical limb-threatening ischemia (CLTI). Successful therapy of DFS goes further, including infection and metabolic control, wound management, offloading the foot and lifelong prophylaxis in the course of a multidisciplinary treatment concept. Revascularization is not needed in all cases of DFS. Conclusions: There are fundamental differences between PAD and DFS with respect to pathophysiology, the anatomical distribution of arterial occlusive processes, the clinical symptoms, the value of diagnostic tools such as the ankle-brachial index, and classification. Also, therapeutic concepts differ substantially between the two patient populations.

Dermal features derived from optoacoustic tomograms via machine learning correlate microangiopathy phenotypes with diabetes stage

Skin microangiopathy has been associated with diabetes. Here we show that skin-microangiopathy phenotypes in humans can be correlated with diabetes stage via morphophysiological cutaneous features extracted from raster-scan optoacoustic mesoscopy (RSOM) images of skin on the leg. We obtained 199 RSOM images from 115 participants (40 healthy and 75 with diabetes), and used machine learning to segment skin layers and microvasculature to identify clinically explainable features pertaining to different depths and scales of detail that provided the highest predictive power. Features in the dermal layer at the scale of detail of 0.1-1 mm (such as the number of junction-to-junction branches) were highly sensitive to diabetes stage. A 'microangiopathy score' compiling the 32 most-relevant features predicted the presence of diabetes with an area under the receiver operating characteristic curve of 0.84. The analysis of morphophysiological cutaneous features via RSOM may allow for the discovery of diabetes biomarkers in the skin and for the monitoring of diabetes status.

A Novel Wound Therapy Modality: Autologous Wound Edge Dotted Full-Thickness Skin Grafting Improving Diabetic Foot Ulcer Healing

Aim

To explore the therapeutic efficacy of autologous wound edge-dotted full-thickness skin grafting in improving diabetic foot ulcer healing.

Methods

Sixty-three patients were divided into three groups: conventional wound therapy (CWT) (n = 23), platelet-rich plasma (PRP) (n = 20), and graft (n = 20). All participants were followed up for 12 weeks. The therapeutic efficacy of the three different wound treatment modalities was analyzed.

Results

After follow-up, 37 (58.7%) patients showed complete wound re-epithelialization, of which 10 (43.5%) occurred in the CWT group, 14 (70.0%) in the PRP group, and 13 (65.0%) in the graft group. Multivariate Cox analysis showed that the independent predictive factors for ulcer healing were different treatment modalities (graft: HR = 3.214, 95% CI=1.300-7.945, P < 0.05; platelet-rich plasma: HR = 3.075, 95% CI=1.320-7.161, P < 0.01), ABI (HR = 9.917, 95% CI=2.675-36.760, P < 0.01), and TcPO2 (HR = 1.040; 95% CI=1.005-1.076; P < 0.05). Stratified analysis showed that higher ABI in graft group or PRP group had higher wound healing rate (graft group: HR = 3.748, 95% CI=1.210-11.607, P < 0.05; PRP group: HR = 5.029, 95% CI=1.743-14.509, P < 0.05); higher TcPO2 in the graft group had higher wound healing rate (HR = 15.805, 95% CI=4.414-56.594, P < 0.01). Additionally, the wound healing time (P < 0.0167) and cumulative healing rate (P < 0.05) in both the PRP group and graft group were more advantageous. The graft group promotes wound re-epithelialization earlier and faster than in the CWT group and PRP group (P < 0.05). Meanwhile, the graft group had lower medical costs (P < 0.0167).

Conclusion

Autologous wound edge dotted full-thickness skin grafting has a higher cost-performance ratio than traditional diabetic foot ulcer wound care and is worthy of further clinical application.

Evaluation of the Angiosome Concept Using Near-Infrared Fluorescence Imaging with Indocyanine Green

BACKGROUND

The angiosome concept is defined as the anatomical territory of a source artery within all tissue layers. When applying this theory in vascular surgery, direct revascularization (DR) is preferred to achieve increased blood flow toward the targeted angiosome of the foot in patients with lower extremity arterial disease (LEAD). This study evaluates the applicability of the angiosome concept using quantified near-infrared (NIR) fluorescence imaging with indocyanine green (ICG).

METHODS

This study included patients undergoing an endovascular- or surgical revascularization of the leg between January 2019 and December 2021. Preinterventional and postinterventional ICG NIR fluorescence imaging was performed. Three angiosomes on the dorsum of the foot were determined: the posterior tibial artery (hallux), the anterior tibial artery (dorsum of the foot) and the combined angiosome (second to fifth digit). The angiosomes were classified from the electronic patient records and the degree of collateralization was classified based on preprocedural computed tomography angiography and/or X-ray angiography. Fluorescence intensity was quantified in all angiosomes. A subgroup analysis based on endovascular or surgical revascularized angiosomes, and within critical limb threatening ischemia (CLTI) patients was performed.

RESULTS

ICG NIR fluorescence measurements were obtained in 52 patients (54 limbs) including a total of 157 angiosomes (121 DR and 36 indirect revascularizations [IR]). A significant improvement of all perfusion parameters in both the directly and indirectly revascularized angiosomes was found (P-values between <0.001-0.007). Within the indirectly revascularized angiosomes, 90.6% of the scored collaterals were classified as significant. When comparing the percentual change in perfusion parameters between the directly and indirectly revascularized angiosomes, no significant difference was seen in all perfusion parameters (P-values between 0.253 and 0.881). Similar results were shown in the CLTI patients subgroup analysis, displaying a significant improvement of perfusion parameters in both the direct and indirect angiosome groups (P-values between <0.001 and 0.007), and no significant difference when comparing the percentual parameter improvement between both angiosome groups (P-values between 0.134 and 0.359). Furthermore, no significant differences were observed when comparing percentual changes of perfusion parameters in directly and indirectly revascularized angiosomes for both endovascular and surgical interventions (P-values between 0.053 and 0.899).

CONCLUSIONS

This study proves that both DR and IR of an angiosome leads to an improvement of perfusion. This suggests that interventional strategies should not only focus on creating in-line flow to the supplying angiosome. One can argue that the angiosome concept is not applicable in patients with LEAD.

Grades of Below-the-Ankle Arterial Occlusive Disease following the Angiosome Perfusion: A New Morphological Assessment and Correlations with the Inframalleolar GVG Stratification in CLTI Patients

PURPOSE

To assess a specific classification of the foot atherosclerotic disease concerning the angiosomal source arteries, the connected foot arches and attached collaterals for Rutherford 5, CLTI patients. To compare eventual analogies of this novel grading system with previously reported GLASS/GVG inframalleolar patterns of occlusive disease (P0-P2).

MATERIALS AND METHODS

A series of 336 ischemic feet (221 diabetics) were selected and retrospectively analyzed. For each angiographic pattern of inframalleolar atherosclerotic disease, 4 severity classes of targeted angiosomal artery path (TAAP), associating 4 other classes concerning linked foot arches (LFA) and collaterals occlusive disease were described. By associating the 4 TAAP with the 4 others parallel LFA and collaterals classes, 4 novel anatomical "Grades" (A-D) of occlusive disease were described. Limb salvage was studied between groups of diabetic and non-diabetic patients.

RESULTS

Using a primary endovascular approach, limb preservation comparison of grade A/B proved without significance for diabetics (P = 0.032) and non-diabetics (P = 0.226). Comparison in diabetics and/or non-diabetics between A/C (P = 0.045 and 0.046), A/D (P = 0.027 and 0.030, B/C (P = 0.009 and 0.038), and B/D (P = 0.006 and P = 0.042), as well as C/D groups (P = 0.048 and P = 0.034) proved ponderous. Parallel analysis of similar grades (A/A, B/B, etc.) with, or without diabetes appeared without significance (P > 0.05). Further comparison between grades A+B (assigned as P0/GVG), versus C (P1), and D (P2), proved significant (P < 0.0001).

CONCLUSION

The present grading system proposes a useful correlation between the severity of foot angiosomal arteries, arches, and collaterals disease and limb salvage, confirming the clinical significance of P0-P2 GVG severity score. This analysis also points the limits of EVT to be probably avoided in grade D patients.

[Diabetic foot syndrome-Part 1 : Definition, pathophysiology, diagnostics and classification]

There are ca. 8 million persons with diabetes mellitus living in Germany. A late sequelae of diabetes is the diabetic foot syndrome (DFS), the prevalence of which is greatly increasing. It comprises all alterations of the foot as a result of diabetic polyneuropathy as well as microvascular and macrovascular (peripheral arterial occlusive disease, PAOD) alterations. Many of the ca. 250,000 newly diagnosed diabetic foot ulcers per year become chronic wounds. Despite intensive efforts for prevention, early diagnosis and adequate wound care, ca. 13,000 persons with diabetes undergo major limb amputation in Germany every year. With consistent treatment in interdisciplinary centers and by exhausting all possible methods of wound treatment, pressure relief as well as arterial revascularization, the major amputation rate in patients with diabetic foot problems can be reduced by 80%. With a suitable strategy of prevention, the recurrence rate of foot ulcers would be reduced.

Stimulation TcPO2 Testing Improves Diagnosis of Peripheral Arterial Disease in Patients With Diabetic Foot

BACKGROUND

All diagnostic procedures of peripheral arterial disease (PAD) in diabetic foot (DF) are complicated due to diabetes mellitus and its late complications.The aim of our study is to enhance diagnosis of PAD using a novel transcutaneous oximetry (TcPO2) stimulation test.

METHODS

The study comprised patients with mild-to-moderate PAD(WIfI-I 1 or 2) and baseline TcPO2 values of 30-50 mmHg.TcPO2 was measured across 107 different angiosomes. Stimulation examination involved a modification of the Ratschow test. All patients underwent PAD assessment (systolic blood pressures (SBP), toe pressures (TP), the ankle-brachial indexes (ABI) and toe-brachial indexes (TBI), duplex ultrasound of circulation). Angiosomes were divided into two groups based on ultrasound findings: group M(n=60) with monophasic flow; group T(n=47) with triphasic flow. Large vessel parameters and TcPO2 at rest and after exercise (minimal TcPO2, changes in TcPO2 from baseline (Δ,%), TcPO2 recovery time) measured during the stimulation test were compared between study groups.

RESULTS

During the TcPO2 stimulation exercise test, group M exhibited significantly lower minimal TcPO2 (26.2 ± 11.1 vs. 31.4 ± 9.4 mmHg; p<0.01), greater Δ and percentage decreases from resting TcPO2 (p=0.014 and p=0.007, respectively) and longer TcPO2 recovery times (446 ± 134 vs. 370 ± 81ms;p=0.0005) compared to group T. SBPs, TPs and indexes were significantly lower in group M compared to group T. Sensitivity and specificity of TcPO2 stimulation parameters during PAD detection increased significantly to the level of SBP, ABI, TP and TBI.

CONCLUSION

Compared to resting TcPO2, TcPO2 measured during stimulation improves detection of latent forms of PAD and restenosis/obliterations of previously treated arteries in diabetic foot patients.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov [https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0009V7W&selectaction=Edit&uid=U0005381&ts=2&cx=3j24u2], identifier NCT04404699.

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.

Retinal microvascular findings and risk of incident peripheral artery disease: An analysis from the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND AIMS

Lower-extremity peripheral artery disease (PAD) is usually considered large artery disease. Interestingly, retinal microvascular findings were shown to predict PAD progression in diabetes. However, it is unknown whether retinal microvascular parameters are associated with incident PAD and its severe form, critical limb ischemia (CLI), in a community-based cohort.

METHODS

Among 9371 ARIC participants (aged 49-72 years) free of a history of PAD, we quantified the associations of several retinal measures by retinal photography during the period 1993-1995 with PAD risk using Cox models. Incident PAD was defined as the first hospitalization with PAD diagnosis or leg revascularization (considered CLI if an additional diagnosis of ulcer, gangrene, or amputation).

RESULTS

During a median follow-up of 18.8 years, 303 participants developed PAD (including 91 CLI cases). Although generalized retinal arteriolar narrowing was not associated with PAD, most measures of retinopathy demonstrated strong associations with PAD beyond potential confounders including diabetes, with adjusted hazard ratios (HR) of 3.26 (95% CI 2.18-4.90) for blot-shaped hemorrhages, 3.11 (1.83-5.29) for hard exudates, and 2.18 (1.62-2.95) for any retinopathy. Adjusted HRs were significantly greater for CLI (ranging from 3.2 to 5.9) than for PAD (all p-values <0.05). Retinopathy measures showed particularly strong associations in participants with diabetes (p-value for interaction [vs. those without diabetes] <0.001).

CONCLUSIONS

Several retinopathy measures were strongly associated with PAD, especially with CLI and in diabetes. Our results support the contribution of microvascular abnormalities to the development and progression of PAD and would have implications on its preventive and therapeutic approaches.

Peripheral arterial disease: Scoping review of patient-centred outcomes

Peripheral arterial disease (PAD) impairs patients' quality of life (QOL), walking and ulcer healing, increasing patient pain, costs, and risks of amputation or mortality. A literature appraisal described PAD treatment capacity to improve validated patient-centred outcomes in controlled clinical studies. The PUBMED database was searched from 1 January 1970 to 21 June 2018, for original and derivative controlled clinical trial references addressing MeSH terms for 'ischemia' AND 'leg ulcer'. Non-ischemic ulcer treatment references were excluded. Frequencies of improved (P < .05) outcomes were reported. Eighty-eight studies on 4153 patients were summarized. Walking, pain or QOL improved mainly for interventions administered before PAD became severe. Amputation incidence, pain and ulcer healing were more frequently reported in those with severe PAD. Independent of PAD severity, patients experienced more likely improved walking, QOL, or pain reduction in response to structured walking interventions or those increasing calf muscle activity. Those with more severe PAD were more likely to report amputation reduction, mainly in response to invasive interventions. Those with PAD experienced more consistently improved patient-centred outcomes if they received multidisciplinary PAD management with supervised walking or calf muscle activity, with more likely amputation risk reduced for those with more severe PAD.

Pulse Oximetry as a Screening Test for Hemodynamically Significant Lower Extremity Peripheral Artery Disease in Adults with Type 2 Diabetes Mellitus

Objective

The main objective is to determine if digital pulse oximetry is an acceptable screening tool to detect hemodynamically significant lower extremity peripheral artery disease (PAD) in patients 50 years old and above with type 2 diabetes mellitus (T2DM) seen at the University of Santo Tomas Hospital (USTH).

Methodology

A total of 78 subjects (155 limbs) were included. Using duplex ultrasonography as the reference standard for the presence of hemodynamically significant lower extremity PAD, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained for abnormal percent oxygen saturation (SpO₂) gradients and for ankle-brachial index (ABI).

Results

Of the 155 limbs, 38.7% had hemodynamically significant stenosis. Pulse oximetry had 76.7% sensitivity (95% CI, 65.2% to 88.1%), 85.3% specificity (95% CI, 78.0% to 92.6%), 76.7% PPV (95% CI, 66.5% to 84.4%) and 85.3% NPV (95% CI, 78.4% to 90.2%). ABI had 40.7% sensitivity (95% CI, 30.1% to 51.3%), 88.2% specificity (95% CI, 80.0% to 96.3%), 68.6% PPV (95% CI, 53.6% to 80.4%) and 70.1% NPV (95% CI, 65.1% to 74.5%). Combining both produces 88.1% sensitivity (95% CI, 78.5% to 97.8%), 74.2% specificity (95% CI, 65-83.4%), 68.4 PPV (95% CI, 60.3% to 75.6%) and 90.8% NPV (95% CI, 83.0% to 95.2%).

Conclusion

The results of this study suggest that pulse oximetry has a higher sensitivity than ABI as a screening tool for hemodynamically significant lower extremity PAD in T2DM patients 50 years old and above. Combining these two tests may be done to achieve a higher sensitivity.

Supervised short-stretch compression therapy in mixed leg ulcers

OBJECTIVES

This study was conducted to determine hemodynamic and clinical tolerance under short-stretch compression therapy in elderly patients suffering from mixed-etiology leg ulcers.

DESIGN

Transversal observational study conducted in 25 hospitalized patients with a moderate peripheral arterial occlusive disease defined as an ankle-brachial pressure index>0.5, an ankle pressure of>70mmHg and a toe cuff pressure (TP)>50mmHg.

MATERIAL AND METHODS

Short-stretch bandages were applied daily with pressures from 20 to 30mmHg. Ankle-brachial pressure, great toe laser Doppler flowmetry (LDF) and transcutaneous oxygen pressure (TcPO2) on dorsum of the foot were measured at baseline and after its removal at 24hours. Great toe LDF was also measured at 10minutes after bandage application. Compression pressure (CP) was measured with a sub-bandage device at baseline, at 10minutes and before bandage removal at 24hours. Clinical tolerance was evaluated taking into account the patient's pain and skin tolerance.

RESULTS

Mean age of patients was 80±15 years. Median duration of ulcers was 18 months. Hypertension was highly prevalent. One third of patients had diabetes. Toe pressure index and TcPO2 values did not significantly change under compression therapy (P=0.51 and P=0.09, respectively) whereas CP decreased significantly during 24hours. The loss of CP was significant 10minutes after bandage application (P<0.001). Nearly all ulcers were painful prior to placement of compression therapy and required level 1 analgesics. One patient required level 2 analgesic for pain relief. No increase in pain and no ischemic skin damage occurred under compression therapy.

CONCLUSIONS

In elderly patients with mixed leg ulcers and with an absolute TP>50mmHg, short-stretch compression of up to 30mmHg does not adversely affect arterial flow and appears clinically well tolerated. Such bandages with appropriate levels of compression may aid ulcer healing by treating the venous part of the disease.

Measures of chronic kidney disease and risk of incident peripheral artery disease: a collaborative meta-analysis of individual participant data

BACKGROUND

Some evidence suggests that chronic kidney disease is a risk factor for lower-extremity peripheral artery disease. We aimed to quantify the independent and joint associations of two measures of chronic kidney disease (estimated glomerular filtration rate [eGFR] and albuminuria) with the incidence of peripheral artery disease.

METHODS

In this collaborative meta-analysis of international cohorts included in the Chronic Kidney Disease Prognosis Consortium (baseline measurements obtained between 1972 and 2014) with baseline measurements of eGFR and albuminuria, at least 1000 participants (this criterion not applied to cohorts exclusively enrolling patients with chronic kidney disease), and at least 50 peripheral artery disease events, we analysed adult participants without peripheral artery disease at baseline at the individual patient level with Cox proportional hazards models to quantify associations of creatinine-based eGFR, urine albumin-to-creatinine ratio (ACR), and dipstick proteinuria with the incidence of peripheral artery disease (including hospitalisation with a diagnosis of peripheral artery disease, intermittent claudication, leg revascularisation, and leg amputation). We assessed discrimination improvement through c-statistics.

FINDINGS

We analysed 817 084 individuals without a history of peripheral artery disease at baseline from 21 cohorts. 18 261 cases of peripheral artery disease were recorded during follow-up across cohorts (median follow-up was 7·4 years [IQR 5·7-8·9], range 2·0-15·8 years across cohorts). Both chronic kidney disease measures were independently associated with the incidence of peripheral artery disease. Compared with an eGFR of 95 mL/min per 1·73 m2, adjusted hazard ratios (HRs) for incident study-specific peripheral artery disease was 1·22 (95% CI 1·14-1·30) at an eGFR of 45 mL/min per 1·73 m2 and 2·06 (1·70-2·48) at an eGFR of 15 mL/min per 1·73 m2. Compared with an ACR of 5 mg/g, the adjusted HR for incident study-specific peripheral artery disease was 1·50 (1·41-1·59) at an ACR of 30 mg/g and 2·28 (2·12-2·44) at an ACR of 300 mg/g. The adjusted HR at an ACR of 300 mg/g versus 5 mg/g was 3·68 (95% CI 3·00-4·52) for leg amputation. eGFR and albuminuria contributed multiplicatively (eg, adjusted HR 5·76 [4·90-6·77] for incident peripheral artery disease and 10·61 [5·70-19·77] for amputation in eGFR <30 mL/min per 1·73 m2 plus ACR ≥300 mg/g or dipstick proteinuria 2+ or higher vs eGFR ≥90 mL/min per 1·73 m2 plus ACR <10 mg/g or dipstick proteinuria negative). Both eGFR and ACR significantly improved peripheral artery disease risk discrimination beyond traditional predictors, with a substantial improvement prediction of amputation with ACR (difference in c-statistic 0·058, 95% CI 0·045-0·070). Patterns were consistent across clinical subgroups.

INTERPRETATION

Even mild-to-moderate chronic kidney disease conferred increased risk of incident peripheral artery disease, with a strong association between albuminuria and amputation. Clinical attention should be paid to the development of peripheral artery disease symptoms and signs in people with any stage of chronic kidney disease.

FUNDING

American Heart Association, US National Kidney Foundation, and US National Institute of Diabetes and Digestive and Kidney Diseases.

Vascular assessment of wound healing: a clinical review

Although macrovascular screening of patients with chronic wounds, particularly in the lower extremities, is accepted as part of clinical practice guidelines, microvascular investigation is less commonly used for a variety of reasons. This can be an issue because most patients with macrovascular disease also develop concomitant microvascular dysfunction. Part of the reason for less comprehensive microvascular screening has been the lack of suitable imaging techniques that can quantify microvascular dysfunction in connection with non-healing chronic wounds. This is changing with the introduction of fluorescence microangiography. The objective of this review is to examine macro- and microvascular disease, the strengths and limitations of the approaches used and to highlight the importance of microvascular angiography in the context of wound healing.

An Alteration of Lymphocytes Subpopulations and Immunoglobulins Levels in Patients with Diabetic Foot Ulcers Infected Particularly by Resistant Pathogens

The aim of our study was to analyse immune abnormalities in patients with chronic infected diabetic foot ulcers (DFUs) especially those infected by resistant microorganisms. Methods. 68 patients treated in our foot clinic for infected chronic DFUs with 34 matched diabetic controls were studied. Patients with infected DFUs were subdivided into two subgroups according to the antibiotic sensitivity of causal pathogen: subgroup S infected by sensitive (n = 50) and subgroup R by resistant pathogens (n = 18). Selected immunological markers were compared between the study groups and subgroups. Results. Patients with infected chronic DFUs had, in comparison with diabetic controls, significantly reduced percentages (p < 0.01) and total numbers of lymphocytes (p < 0.001) involving B lymphocytes (p < 0.01), CD4+ (p < 0.01), and CD8+ T cells (p < 0.01) and their naive and memory effector cells. Higher levels of IgG (p < 0.05) including IgG1 (p < 0.001) and IgG3 (p < 0.05) were found in patients with DFUs compared to diabetic controls. Serum levels of immunoglobulin subclasses IgG2 and IgG3 correlated negatively with metabolic control (p < 0.05). A trend towards an increased frequency of IgG2 deficiency was found in patients with DFUs compared to diabetic controls (22% versus 15%; NS). Subgroup R revealed lower levels of immunoglobulins, especially of IgG4 (p < 0.01) in contrast to patients infected by sensitive bacteria. The innate immunity did not differ significantly between the study groups. Conclusion. Our study showed changes mainly in the adaptive immune system represented by low levels of lymphocyte subpopulations and their memory effector cells, and also changes in humoral immunity in patients with DFUs, even those infected by resistant pathogens, in comparison with diabetic controls.

Rearfoot Transcutaneous Oximetry is a Useful Tool to Highlight Ischemia of the Heel

PURPOSE

To demonstrate the usefulness of rearfoot transcutaneous oximetry to assess the peripheral arterial disease in diabetic patients with heel ulcer.

METHODS

From our database of 550 critical limb ischemia diabetic patients followed after a percutaneous transluminal angioplasty, we have selected patients with below the knee arterial disease. Patients were grouped according to the dorsal transcutaneous oximetry value (Group A < 30 mmHg; Group B ≥ 30 mmHg). Patients of Group B had a second oximetry performed at the rearfoot, close to the lesion localized in all cases at the heel. Finally, the analysis of the arterial pattern disease has been done.

RESULTS

We selected 191 patients: Group A (151 patients), dorsal transcutaneous oximetry of 11.8 ± 0.7 mmHg; Group B (40 patients), dorsal transcutaneous oximetry of 44.2 ± 10.1 mmHg. In Group B, rearfoot oximetry was 20.5 ± 5 mmHg, significantly lower than dorsal oximetry (p = 0.0179). The anterior tibial artery was involved in all patients of Group A. In Group B, the anterior tibial artery was involved in 15 subjects and never alone; the posterior tibial artery was involved in 20 subjects and in 11 cases alone. The peroneal artery was affected in 20 subjects and in 14 patients alone.

CONCLUSION

When a heel lesion is present and the transcutaneous oximetry recorded on the dorsum of the foot does not confirm the presence of critical limb ischemia (not ≤30 mmHg), a second oximetry recorded on the rearfoot is useful to point out ischemia of the peroneal artery and/or of the posterior tibial artery.

Sociodemographic and clinical characteristics of patients with diabetic foot ulcer

Summary Introduction: Diabetic foot is one of the most serious complications of diabetes affecting about 15% of all diabetes patients, and it is the leading cause of nontraumatic lower limb amputations. This study presents a sociodemographic and clinical characterization of patients with diabetic foot ulcer indicated for amputation surgery. Methods: A cross-sectional study with 206 patients with type 2 diabetes and a diabetic foot ulcer indicated for amputation surgery. Patients were assessed on sociodemographic and clinical characteristics, pain intensity and pain interference, after answering the Brief Pain Inventory, and on pain descriptors according to the Douleur Neuropathique 4. Results: Most patients were male, with little formal education and a mean age of 66 years. They had been diagnosed with type 2 diabetes for 18 years on average, and with diabetic foot ulcer on average 4 years prior to the assessment. About 59% of patients experienced pain in the lower limb that significantly affect all areas of their functioning. Conclusion: The social demographic variables play an important role in diabetic foot ulceration. Given that the neuropathic ulcers are more easily preventable, systematic monitoring of patients with neuropathy is important. In patients with neuroischemic foot, strategies to cope or manage more efficiently the pain are paramount. Intervention should be multidisciplinary and take into account sociodemographic and clinical factors, as well as the presence, intensity and interference of pain in the patient's daily life activities and whether the patient has family or caregiver support.

The phagocytic fitness of leucopatches may impact the healing of chronic wounds

Chronic non-healing wounds are significantly bothersome to patients and can result in severe complications. In addition, they are increasing in numbers, and a challenging problem to the health-care system. Handling of chronic, non-healing wounds can be discouraging due to lack of improvement, and a recent explanation can be the involvement of biofilm infections in the pathogenesis of non-healing wounds. Therefore, new treatment alternatives to improve outcome are continuously sought-after. Autologous leucopatches are such a new, adjunctive treatment option, showing promising clinical effects. However, the beneficial effect of the patches are not understood fully, although a major contribution is believed to be from the release of stimulating growth factors from activated thrombocytes within the leucopatch. Because the leucopatches also contain substantial numbers of leucocytes, the aim of the present study was to investigate the activity of the polymorphonuclear neutrophils (PMNs) within the leucopatch. By means of burst assay, phagocytosis assay, migration assay, biofilm killing assay and fluorescence in-situ hybridization (FISH) assay we showed significant respiratory burst in PMNs, active phagocytosis and killing of Pseudomonas aeruginosa by the leucopatch. In addition, bacterial-induced migration of PMNs from the leucopatch was shown, as well as uptake of P. aeruginosa by PMNs within the leucopatch. The present study substantiated that at least part of the beneficial clinical effect in chronic wounds by leucopatches is attributed to the activity of the PMNs in the leucopatch.

Prediction of Development of Critical Limb Ischemia in Hemodialysis Patients

Hemodialysis (HD) patients with critical limb ischemia (CLI) suffer chronic inflammation and repeated infection, require intervention, and may have a protracted hospital stay. Therefore, early prediction is particularly important for management of CLI in patients with suspected peripheral artery disease. The purpose of this study is to develop a simple score for predicting the incidence of CLI in HD patients with suspected peripheral artery disease. The subjects were 139 asymptomatic patients receiving maintenance HD and with ABI <1.0. Multivariate logistic regression analysis was used to identify factors associated with development of CLI. These factors were subsequently weighted and integrated into a scoring system for the prediction of onset of CLI. Twenty-five patients had onset of CLI. Five factors selected from the multivariate model were weighted proportionally using their respective odds ratio (OR) for incidence of CLI (history of cerebral vascular disease, OR 6.42 [3 points]; diabetes, OR 3.92 [2 points]; hypoesthesia, OR 4.21 [2 points]; left ventricular ejection fraction <50%, OR 3.89 [2 points]; serum albumin <3.5 g/dL, OR 4.39 [2 points]). Three strata of risk were defined (low risk, 0 to 3 points; intermediate risk, 4 to 6 points; and high risk 7 to 11 points) with excellent prognostic accuracy for progression to CLI using the Kaplan-Meier method. Five factors were identified that increased the risk of progression to CLI in HD patients with suspected peripheral artery disease. A combination of those factors permitted establishment of three risk strata for accurate prediction of onset of CLI.

Measure the Vascular Flow Volume rather than Vascular Stenosis and Pressure Gradient

We aimed to investigate the extent to which measurements of flow volume (FV) with colour flow duplex ultrasonography (CDU) could predict tissue perfusion. A 68 year-old male patient was admitted to our clinic complaining of intermittent claudication in the right leg. Digital subtraction angiography showed total occlusion of the right femoral artery. The right popliteal artery (PA) was filling by collaterals. CDU showed that the FV in the right PA was higher than in the left. Arterial-venous FV measurement with CDU should be performed rather than the detection of arterial stenosis to assess whether intervention is necessary.

Hyperglycemia increases susceptibility to ischemic necrosis

Diabetic patients are at risk for spontaneous foot ulcers, chronic wounds, infections, and tissue necrosis. Current theories suggest that the development and progression of diabetic foot ulcers are mainly caused by arteriosclerosis and peripheral neuropathy. Tissue necrosis plays a primordial role in the progression of diabetic foot ulcers but the underlying mechanisms are poorly understood. The aim of the present study was to investigate the effects of hyperglycemia per se on the susceptibility of ischemic tissue to necrosis, using a critical ischemic hind limb animal model. We inflicted the same degree of ischemia in both euglycemic and streptozotocin-induced hyperglycemic rats by resecting the external iliac, the femoral, and the saphenous arteries. Postoperative laser Doppler flowmetry of the ischemic feet showed the same degree of reduction in skin perfusion in both hyperglycemic and euglycemic animals. Nevertheless, we found a significantly higher rate of limb necrosis in hyperglycemic rats compared to euglycemic rats (71% versus 29%, resp.). In this study, we revealed that hyperglycemia per se increases the susceptibility to limb necrosis in ischemic conditions. Our results may help to better understand the physiopathology of progressive diabetic wounds and underline the importance of strict glycemic control in patients with critical limb ischemia.