Predictive value of transcutaneous oxygen pressure and amputation success by use of supine and elevation measurements

Vascular Assessment in Patients With a Lower Limb Wound: A Correlational Study of Photoplethysmography and Laser Doppler Flowmetry Toe Pressure Techniques

BACKGROUND

Vascular assessment of the lower limbs is essential in patients with diabetes. In the presence of noncompressible arteries, the ankle brachial index (ABI) can either be inconclusive or provide false-positive results. Toe pressure measurement has been suggested as an alternative as a noninvasive method for detecting peripheral arterial disease (PAD). Toe pressure measurement can be performed either by photoplethysmography (PPG) or by Laser Doppler flowmetry (LDF). The aim of this study was to determine correlations between the two techniques in order to promote the use of PPG in clinical practice.

METHODS

This was a prospective correlational study of 108 consecutive recruited adult patients, with and without diabetes, with at least one lower limb wound from a University-affiliated hospital wound care clinic. Toe pressure measurements were both performed with PPG and LDF devices.

RESULTS

Mean toe pressure values for PPG and LDF were, respectively, 83.7 (SD 35.4) and 79.5 (SD 32.0) mmHg (with a paired t-test 3.969, P < 0.01). In patients with at least one lower limb wound, a strong linear relation was found between PPG and LDF toe pressure techniques with a Pearson's r correlation coefficient of 0.920 (P < 0.001).

CONCLUSIONS

PPG and LDF toe pressure techniques are equivalent in patients with at least one lower limb wound, irrespective of the presence of diabetes. Therefore, in the presence of an ABI with inconclusive results, such as in a patient with noncompressible vessels, both toe pressure techniques can be used for assessing the vascular supply of the lower limb with a wound.

Update on the pathogenesis and treatment of skeletal fragility in type 2 diabetes mellitus

Fracture risk is increased in patients with type 2 diabetes mellitus (T2DM). In addition, these patients sustain fractures despite having higher levels of areal bone mineral density, as measured by dual-energy X-ray absorptiometry, than individuals without T2DM. Thus, additional factors such as alterations in bone quality could have important roles in mediating skeletal fragility in patients with T2DM. Although the pathogenesis of increased fracture risk in T2DM is multifactorial, impairments in bone material properties and increases in cortical porosity have emerged as two key skeletal abnormalities that contribute to skeletal fragility in patients with T2DM. In addition, indices of bone formation are uniformly reduced in patients with T2DM, with evidence from mouse studies published over the past few years linking this abnormality to accelerated skeletal ageing, specifically cellular senescence. In this Review, we highlight the latest advances in our understanding of the mechanisms of skeletal fragility in patients with T2DM and suggest potential novel therapeutic approaches to address this problem.

What Is Currently the Role of TcPO2 in the Choice of the Amputation Level of Lower Limbs? A Comprehensive Review

Some patients still require major amputation for lower extremity peripheral arterial disease treatment. The purpose of pre-operative amputation level selection is to determine the most distal amputation site with the highest healing probability without re-amputation. Transcutaneous oximetry (TcPO2) can detect viable tissue with the highest probability of healing. Several factors affect the accuracy of TcPO2; nevertheless, surgeons rely on TcPO2 values to determine the optimal amputation level. Background about the development of TcPO2, methods of measurement, consequences of lower limb amputation level, and the place of TcPO2 in the choice of the amputation level are reviewed herein. Most of the retrospective studies indicated that calf TcPO2 values greater than 40 mmHg were associated with a high percentage of successful wound healing after below-knee-amputation, whereas values lower than 20 mmHg indicated an increased risk of unsuccessful healing. However, a consensus on the precise cut-off value of TcPO2 necessary to assure healing is missing. Ways of improvement for TcPO2 performance applied to the optimization of the amputation-level are reported herein. Further prospective data are needed to better approach a TcPO2 value that will promise an acceptable risk of re-amputation. Standardized TcPO2 measurement is crucial to ensure quality of data.

Determinants of Bone Material Strength and Cortical Porosity in Patients with Type 2 Diabetes Mellitus

CONTEXT

Reduced bone material strength index (BMSi) and increased cortical porosity (CtPo) have emerged as potentially contributing to fracture risk in type 2 diabetes mellitus (T2DM) patients.

OBJECTIVE

To determine whether BMSi or CtPo are related to other diabetic complications.

DESIGN

Cross-sectional observational study.

SETTING

Subjects recruited from a random sample of southeast Minnesota residents.

PARTICIPANTS

A total of 171 T2DM patients (mean age, 68.8 years) and 108 age-matched nondiabetic controls (mean age, 67.3 years).

MAIN MEASURES

Bone material strength index was measured using microindentation, skin advanced glycation end-products (AGEs) measured using autofluorescence, high-resolution peripheral quantitative computed tomography at the distal radius and tibia, assessment of diabetic microvascular complications including urine microalbuminuria, retinopathy, neuropathy, and vascular disease (ankle brachial index and transcutaneous oxygen tension [TcPO2]). All analyses were adjusted for age, sex, and body mass index.

RESULTS

Skin AGEs were negatively correlated with the BMSi in both T2DM (r = -0.30, P < 0.001) and control (r = -0.23, P = 0.020) subjects. In relating diabetic complications to CtPo, we found that T2DM patients with clinically significant peripheral vascular disease (TcPO2 ≤ 40 mm Hg) had higher (+21.0%, P = 0.031) CtPo at the distal tibia as compared to controls; in these subjects, CtPo was negatively correlated with TcPO2 at both the distal tibia (r = -0.39, P = 0.041) and radius (r = -0.41, P = 0.029).

CONCLUSIONS

Our findings demonstrate that bone material properties are related to AGE accumulation regardless of diabetes status, while CtPo in T2DM patients is linked to TcPO2, a measure of microvascular blood flow.

The Impact of Extracorporeal Shock Wave Therapy on Microcirculation in Diabetic Feet: A Pilot Study

BACKGROUND

Patients with diabetic foot commonly experience vascular insufficiency and compromised tissue perfusion. Extracorporeal shockwave therapy (ESWT) reportedly promotes wound healing and angiogenesis, but clinical studies on the effect of ESWT on angiogenesis are scarce and the exact mechanism remains unclear.

OBJECTIVE

To investigate the effect of ESWT on cutaneous microcirculation in diabetic feet.

METHODS

Ten patients with diabetic feet received ESWT twice weekly for a total of six sessions. Transcutaneous partial oxygen pressure (TcPO2) and cutaneous blood flow were measured before and after ESWT.

MAIN RESULTS

The treated feet showed statistically significant improvements in the mean TcPO2 (P < .01) and cutaneous blood flow level (P < .05) compared with control feet. In treated feet, TcPO2 increased by 19.6%, from 41.4 ± 9.9 to 49.5 ± 8.7 mm Hg (P < .05). In control feet, TcPO2 decreased by 11.6%, from 39.5 ± 14.0 to 34.9 ± 14.5 mm Hg (P = .059). The average cutaneous blood flow level of treated feet before ESWT was 36.9 ± 25.6, which increased to 48.3 ± 32.4 AU after ESWT (30.9% increase; P = .646). In control feet, the cutaneous blood flow level decreased from 80.5 ± 36.7 to 60.4 ± 38.8 AU, a decrease of 25.0% (P = .241).

CONCLUSIONS

These results demonstrate that ESWT may have beneficial effects on microcirculation in diabetic feet.

A New Modified Surgical Technique of In Situ Reverse Arterialization: Leaving the Distal Saphenous Side Branches Open of Nonreconstructable Ischemic Leg Leads to Full Recovery

BACKGROUND

Arterialization of the foot veins in patients with ischemic foot usually result in excessive foot edema, wound infection, venous gangrene, long hospitalization duration, and a high rate of amputation. We herein present an improved method of foot revascularization via the superficial venous system by in situ reverse arterialization (ISRA) of the foot venous bed, leaving the distal saphenous side branches open.

METHODS

A 69-year-old patient with toe wet gangrene and end-stage peripheral vascular disease with absence of foot target arteries underwent ISRA procedure, using the great saphenous vein, which was anastomosed end-to-side to the proximal superficial femoral artery. Only proximal saphenous tributaries were ligated until arterial flow reached the pedal superficial veins.

RESULTS

Postoperatively, the foot regained normal pulsation over the superficial venous system. The patient did not experience foot edema. On-table subtraction angiography demonstrated arterial flow through the long saphenous and dorsal foot veins, with returned venous flow through the anterior and posterior tibial veins. Methoxyisobutylisonitrile scan conducted 4 weeks postoperatively demonstrated positive oxygen uptake of the pedal muscles, which was absent before surgery. Electron microscopy of the muscles at the level of the transmetatarsal amputation demonstrated regeneration of muscle tissue with mitosis 6 weeks postoperatively. During 1,000 days of follow-up postsurgery, the flow was reduced and the transcutaneous pO₂ level of the foot increased up to 76 mm Hg.

CONCLUSIONS

This new modified surgical technique of ISRA, in which only proximal saphenous tributaries were ligated in order to prevent high systemic pressure in the foot venous low pressure system, resulted in increased levels of transcutaneous pO₂ and reduced flow, leading to full recovery of the ischemic foot.

Tissue Oxygenation and Negative-Pressure Wound Therapy When Applied to the Feet of Persons With Diabetes Mellitus: An Observational Study

PURPOSE

Our group has reported that negative-pressure wound therapy (NPWT) decreases tissue oxygenation by 84% in the foot of diabetic patients because the pad of the connecting drainage tube and foam sponge of the NPWT system compress the wound bed. The purpose of this study was to determine whether an NPWT modified dressing application reduces tissue oxygenation in the feet of persons with diabetes mellitus.

DESIGN

A prospective, clinical, observational study.

SUBJECTS AND SETTING

We enrolled 30 patients with diabetic mellitus; their mean age was 63.9 ± 11.2 years (mean ± standard deviation). All were cared for at the diabetic wound center at an academic tertiary medical center in South Korea between 2014 and January 2015.

METHODS

Transcutaneous partial oxygen pressures (TcpO2) were measured to determine tissue oxygenation levels beneath modified NPWT dressings. A TcpO2 sensor was fixed at the tarsometatarsal area of the contralateral unwounded foot. A negative pressure of -125 mm Hg was applied until TcpO2 reached a plateau state; values were measured before, during, and after the modified NPWT. The Wilcoxon' and Mann-Whitney U tests were used to compare differences between these measurements.

RESULTS

TcpO2 levels decreased by 26% during the modified NPWT. Mean TcpO2 values before, during, and after turning off the therapy were 54.3 ± 15.3 mm Hg, 41.6 ± 16.3 mm Hg, and 53.3 ± 15.6 mm Hg (P < .05), respectively.

CONCLUSION

Applying NPWT without the pad of the connecting drainage tube significantly reduces the amount of tissue oxygenation loss beneath foam dressings on the skin of the foot dorsum in diabetic patients.

Below-Knee Amputation Failure and Poor Functional Outcomes Are Higher Than Predicted in Contemporary Practice

OBJECTIVE

The perceived functional benefit of below-knee amputation (BKA) must be carefully weighed against the need for potential reinterventions. This study sought to examine the contemporary clinical and functional outcomes of patients undergoing BKA in the endovascular era.

METHODS

All patients who underwent BKA from January 2008 to December 2014 at a single tertiary medical center were retrospectively reviewed. Demographics, comorbidities, ambulation status, and transcutaneous oximetry (TcPO2) values were recorded. Study end points included freedom from conversion to above-knee amputation (AKA), freedom from conversion to AKA or death, BKA healing, and ambulation. Statistical modeling was performed to determine associations with BKA failure.

RESULTS

Over the study interval, 130 limbs underwent BKA in 120 patients. Transcutaneous oximetry studies were obtained in 65% (n = 85). Thirty-eight percent (n = 46) of all BKA patients went on to heal and ambulate. Twenty-five percent (n = 33) required reintervention, 24 with conversion to AKA, and 9 with BKA revision. One-year freedom from conversion to AKA was 76% and was decreased among those with lower TcPO2 levels (60% TcPO2 <40 vs 81% TcPO2 ≥40; P = .04). One-year composite freedom from conversion to AKA/death was 60% and was decreased among those with lower TcPO2 readings (39% TcPO2 <40 vs 69% TcPO2 ≥40; P = .01).

CONCLUSION

Despite a perceived functional bias toward knee salvage at the time of major amputation, most patients failed to postoperatively ambulate. Those with decreased TcPO2 levels (<40 mm Hg) have a 2-fold higher risk of AKA conversion or death, while nearly one-fourth of all BKA patients will succumb to the same fate irrespective of TcPO2. This suggests that many BKA patients in the endovascular era fail to derive the perceived benefit of knee salvage at the time of their index amputation. These findings highlight the need for careful patient selection and for a shared decision-making model in this frail population.

Outcome Following Below-Knee Amputation for Limb Ischemia: A Multivariate Odds Ratio Analysis of Clinical Variables

One hundred and eleven consecutive patients undergoing below-knee amputation for end-stage limb ischemia were reviewed. Decision on the level of amputation was made mainly on clinical grounds. Univariate and multivariate analyses of the outcomes, including revision to above-knee amputation and ability to walk, were carried out for seven preoperative clinical variables related to history alone. Median age was seventy-one years old and there were 74 men. Fifty percent of the patients were diabetic, 14% had neurologic dysfunction, 17% had undergone remote revascularization, 25% had undergone contralateral lower extremity amputation, and 23% underwent unsuccessful attempt at foot salvage prior to amputation. Operative mortality was 10% and morbidity excluding wound complications was 14.5%. Wound complications not requiring further surgery occurred in 10 patients who all eventually walked with a prosthesis. Incidence of revision to above-knee amputation was 19%. Diabetics had less occurrence of this event (odds ratio 0.3, p=0.011). Twenty-five patients were lost at one-year follow-up. Sixty-two % of patients were alive at greater than one year postoperatively and 49% were able to walk with a prosthesis. Potential for rehabilitation among patients with below-knee amputation was adversely affected by preoperative neurologic dysfunction (odds ratio 11.8, p=0.003) and favored by remote lower extremity revascularization (odds ratio 0.3, p=0.04). In patients who required revision to above-knee amputations (n=21), only 38% were able to walk with a prosthesis as compared with 51% for those who did not require stump revisions (p=0.065). Interestingly, there was no effect of age detected on either survival or rehabilitation to walk. Ability to identify high-risk patients will facilitate their selection for primary above-knee amputations.

Cilostazol Can Increase Skin Oxygen Supply Assessed by Transcutaneous Oxygen Pressure Measurement in Type 2 Diabetes With Lower Limb Ischemic Disease: A Randomized Trial

PURPOSE

The purpose of this study was to compare the efficacy and safety of cilostazol versus acetylsalicylic acid (ASA) for amelioration of lower limb ischemia in type 2 diabetes.

DESIGN

Prospective, randomized positive-controlled open clinical trial.

SUBJECTS AND SETTING

Eighty-nine patients with type 2 diabetes mellitus and symptoms of lower limb ischemia (perceptions of coldness of the lower limbs, numbness, intermittent claudication, or pain at rest) present for 6 months or more that had not significantly changed within the past 3 months participated in the study. All subjects had an initial transcutaneous oxygen pressure (TcpO2) of less than 40 mm Hg in the foot when measured in the supine position. Subjects included 46 males and 43 females; their ages ranged from 35 to 80 years.

METHODS

Participants were randomly allocated to 2 groups, one was treated with cilostazol 100 mg taken twice daily (n = 48), and a second group took 100 mg of ASA daily (n = 41) for 8 weeks. Clinical assessment included measurement of transcutaneous oxygenation, and symptoms associated with lower limb ischemia. Blood analyses included a full blood panel, coagulation screen, renal function tests, hepatic function tests, and lipid profiles. All tests were performed at baseline and repeated at 8 weeks.

RESULTS

Age, duration of diabetes, diabetic complications, lower limb ischemic symptoms, TcpO2, and smoking status did not differ between the 2 groups. In contrast, TcpO2 significantly improved from 37.1 ± 11.9 mm Hg to 42.0 ± 9.7 mm Hg in the cilostazol-treated group (P < .05), whereas no significant change was observed in the ASA-treated group (P > .05). Ischemic symptoms such as intermittent claudication (P = .009), perception of limb coldness (P = .008), and pain at rest (P = .017) showed greater improvement in the cilostazol-treated group when compared to subjects treated with ASA. Approximately 10% of patients treated with cilostazol experienced adverse side effects (palpitations, headache, diarrhea). Cilostazol was not found to have significant detrimental effects in hematologic or biochemical indices, including renal, hepatic, and blood coagulant function tests.

CONCLUSIONS

We found that 8 weeks of treatment with cilostazol 100 mg daily was safe and well tolerated for the treatment of type 2 diabetes with lower limb ischemic disease.

Partial foot amputations for salvage of the diabetic lower extremity

Lower extremity infections are a common yet unfortunate complication of diabetes-related ulcers often requiring surgical intervention. The main goals of surgical treatment consist of selecting the appropriate procedure to effectively eradicate nonsalvageable tissue, achieve primary healing, and maximize subsequent dynamic functionality. An overview of each partial foot amputation procedure is discussed with a focus on procedure selection as well as standard and advanced surgical techniques. The effective application of partial foot amputations in the high-risk diabetic population can act to minimize the need for major proximal lower limb amputations.

Evaluation of the diabetic foot according to Wagner’s classification in a rural teaching hospital

Diabetic foot is a common, preventable complication of diabetes mellitus. This was a prospective study (April 2004 to October 2005) of 55 diabetic foot patients attending surgical out and in-patient departments at a rural hospital in Mahrastra, India. To determine the prevalence of diabetic foot amongst our patients with diabetes and the associated risk factors. All patients underwent medical assessment, including foot examination, those with diabetic foot answered an interviewer-administered questionnaire on foot healthcare practices. Symptoms, examination findings, glycaemic control, duration and classification of diabetes, occupation and smoking habits were cross studied with diabetic foot according to Wagner’s grading. The prevalence of diabetic foot was 11% and 84% of patients were men. The commonest presentation was Wagner’s grade 2 diabetic foot (34.5%) and most patients (69%) worked outside. The majority of patients with Wagner’s grade 2—5 had uncontrolled diabetes. Neuropathic and vasculopathic components were major predictors of diabetic foot. More than half (64.5%) of our patients were ignorant of foot healthcare practices. Patients with diabetes at this rural clinic need to be better informed on how to examine and care for their feet. They would also benefit from measures to help them improve glycaemic control.

Spinal cord stimulation for patients with inoperable chronic critical leg ischemia

BACKGROUND

Because of the prevalence of diabetes, the treatment of diabetic foot is still challenging. Even an exactly proved effective and practical method can't be listed except vascular surgery which is not a long-term way for it. Spinal cord stimulation (SCS) is a very promising option in the treatment algorithm of inoperable chronic critical leg ischemia (CLI).

DATA SOURCES

We searched Pubmed database with key words or terms such as "spinal cord stimulation", "ischemic pain" and "limb ischemia" appeared in the last five years.

RESULTS

The mechanism of SCS is unclear. Two theories have emerged to interpret the benefits of SCS. Pain relief from SCS can be confirmed by a majority of the studies, while limb salvage and other more ambitious improvements have not come to an agreement. The complications of SCS are not fatal, but most of them are lead migration, lead connection failure, and local infection.

CONCLUSIONS

SCS is a safe, promising treatment for patients with inoperable CLI. It is effective in pain reduction compared with traditional medical treatment.

The vascular and biochemical effects of cilostazol in patients with peripheral arterial disease

OBJECTIVES

Cilostazol improves walking distance and quality of life in patients with peripheral arterial disease (PAD). This study assessed the vascular and biochemical effects of cilostazol therapy in PAD patients.

METHODS

PAD patients were prospectively recruited to a randomized, double-blinded, placebo-controlled trial. Baseline clinical data were recorded. Clinical assessment included measurement of arterial compliance, transcutaneous oxygenation, ankle-brachial index (ABI), and treadmill walking distance. Blood analyses included a full blood panel, coagulation screen, urea and electrolytes, liver function tests, estimated glomerular filtration rate, and lipid profiles. Quality of life indices were recorded using validated generic and walking-specific questionnaires. All tests were performed at baseline, 6, and 24 weeks.

RESULTS

Eighty patients (53 men) were recruited from December 2004 to January 2006. The cilostazol group had a significant reduction in the augmentation index compared with the placebo group at 6 weeks (19.7% vs 26.7%, P = .001) and at 24 weeks (19.7% vs 27.7%, P = .005). A paradoxic reduction in transcutaneous oxygenation levels was identified in the cilostazol group for the left foot at 6 weeks and for the right foot at both 6 and 24 weeks. The ABIs were not significantly different between treatment groups at baseline, 6 weeks, or 24 weeks for the left and right lower limbs. The mean percentage change in walking distance from baseline improved more markedly in the cilostazol compared with the placebo group for absolute claudication distance at 6 (78.6% vs 26.4%, P = .20) and 24 weeks (173.1% vs 92.1%, P = .27); however, these failed to reach significance. Significant improvements in lipid profiles were demonstrated with cilostazol therapy at 6 weeks (triglycerides, high-density lipoprotein [HDL]) and at 24 weeks (cholesterol, triglycerides, HDL, and low-density lipoprotein). The cilostazol treatment group demonstrated significant improvements in the Short Form-36 (physical functioning, physical component score), Walking Impairment (distance and speed), and Vascular Quality of Life (pain) indices at 6 and 24 weeks. Although cilostazol was associated with side effects in approximately one-third of patients, most settled within 6 weeks, facilitating the continuation of therapy in >89%.

CONCLUSION

Cilostazol is a well-tolerated, safe, and efficacious treatment for PAD patients. It not only improves patients' symptomatology and quality of life but also appears to have beneficial effects on arterial compliance, possibly through its lipid-lowering property.

A review of the clinical significance of tissue hypoxia measurements in lower extremity wound management

The aim of this paper is to review techniques that are currently available to measure tissue hypoxia in order to benefit the management of wounds. Direct measurement of tissue partial oxygen pressure (PO(2)) is invasive and therefore unappealing in clinical practice. Several techniques (PET scans, MRI derived techniques) are primarily applicable to research rather than clinical applications. Imaging techniques (duplex ultrasonography, arteriography, MRI techniques) are recommended only as part of the workup for revascularisation. Techniques that assess local perfusion include clearance methods, transcutaneous O(2) and CO( 2) pressure measurement, and laser Doppler flowmetry and imaging. These techniques permit interpretation of altered perfusion states. Each technique offers subtly different information concerning microvascular function. All these techniques require strict protocols to derive reliable data. The potential of the promising near infrared reflectance spectroscopy (NIRS) technique is yet to be determined.

Treatment of ischemic wounds with noncontact, low-frequency ultrasound: the Mayo clinic experience, 2004-2006

OBJECTIVE

To evaluate the clinical role of a novel, noncontact, low-intensity, low-frequency ultrasound therapy (MIST Therapy) in the treatment of nonhealing leg and foot ulcers associated with chronic critical limb ischemia.

DESIGN

Prospective, parallel-group, randomized, controlled trial.

SETTING

A multidisciplinary, vascular wound-healing clinic.

PATIENTS

Thirty-five patients who received MIST Therapy plus the standard of wound care (treatment group) and 35 patients who received the standard of wound care alone (control group).

INTERVENTIONS

Standard of wound care alone or standard of wound care plus MIST Therapy for 12 weeks or until fully healed. MIST Therapy was administered 3 times per week for 5 minutes per treatment.

MAIN OUTCOME MEASURE

Percentage of patients with greater than 50% reduction in wound size from the index measurement after 12 weeks of treatment. The relationship of transcutaneous oximetry pressure in the supine and dependent position was evaluated as a factor in assessing the potential to heal ischemic ulcerations of the foot and leg.

MAIN RESULTS

A significantly higher percentage of patients treated with the standard of care plus MIST Therapy achieved greater than 50% wound healing at 12 weeks than those treated with the standard of care alone (63% vs 29%; P < .001). Thus, failure to achieve the minimum wound healing requirement occurred in 37% of patients in the treatment group and 71% of patients in the control group. The predictive value of baseline transcutaneous oxygen pressure may benefit the clinician when assessing the potential to heal ischemic wounds.

CONCLUSION

The rate of healing of cutaneous foot and leg ulcerations in patients with chronic critical limb ischemia improved significantly when MIST Therapy was combined with the standard of wound care.

Beneficial effects of dalteparin on haemostatic function and local tissue oxygenation in patients with diabetes, severe vascular disease and foot ulcers

INTRODUCTION

A state of hypercoagulation and fibrinolytic dysfunction is present in individuals with diabetes, which may contribute to disturbed skin microcirculation and impaired ulcer healing. We have previously reported an improved outcome of chronic diabetic foot ulcers during treatment with dalteparin. In the present study we investigated the effects of dalteparin on skin microcirculation and haemostatic function.

MATERIALS AND METHODS

87 patients with diabetes, peripheral arterial obliterative disease and chronic foot ulcers were investigated in a prospective, randomised, double-blind and placebo-controlled study. They were randomised to treatment with subcutaneous injections of 5000 U dalteparin (n=44) or placebo (n=43), once daily until ulcer healing or for a maximum of six months. Plasma fibrinogen, fibrin gel structure [permeability coefficient (Ks) and fiber mass/length ratio (mu)], prothrombin fragment 1+2 (F1+2) antigen, plasminogen activator inhibitor-1 (PAI-1) activity and tissue plasminogen activator (tPA) antigen were analysed before randomization (baseline value), and at the end of the treatment period. The skin microcirculation of the foot was investigated by transcutaneous oxygen tension (TcPO(2)) and laser Doppler fluxmetry (LDF).

RESULTS

The changes (Delta-values) of Ks, mu, tPA and TcPO(2) were higher (p<0.05) during treatment with dalteparin, as compared to the changes during treatment with placebo. At baseline, plasma fibrinogen and Ks were significantly correlated to TcPO(2).

CONCLUSIONS

Local skin oxygenation improved and a less thrombogenic fibrin gel structure was formed in patients treated with dalteparin. Beneficial effects on haemostatic function are likely to contribute to the improved skin oxygenation observed during treatment with dalteparin.

Can transcutaneous oxygen tension measurement determine re-amputation levels?

OBJECTIVE

To review the preoperative transcutaneous oxygen tension (TcPO2) measurements in patients having major lower leg amputation, and also consider the re-amputation rate, wound infection and the definitive level of amputation.

METHOD

A case-control study was performed in a consecutive cohort of 170 patients (1999-2003). Fifty-two patients underwent preoperative TcPO2 measurements (cases) and 118 patients did not (control). Multiple logistic regression analysis was performed to analyse independent risk factors associated with re-amputations.

RESULTS

Primary and definitive (in case of a re-amputation) amputation levels were lower in the TcPO2 group, although this did not reach statistical significance. The number of re-amputations in the TcPO2 group was significantly higher: 15 versus 18 patients (p=0.039). Selection of an amputation level with aTcPO2 of 30mmHg resulted in a positive predictive value of re-amputation of 41% and a negative predictive value of 90%. A cut off value of 20mmHg resulted in 41% and 77% respectively.

CONCLUSION

The use of TcPO2 measurements for major amputation level selection resulted in an increased rate of re-amputation. However, there was a trend in gaining a more distal definitive amputation level. Selection of an amputation level solely based on a TcPO2 value is unreliable.

Percutaneous transluminal angioplasty in severe diabetic foot ischemia: outcomes and prognostic factors

OBJECTIVES

To evaluate the outcomes of severe ischemic diabetic foot ulcers for which percutaneous transluminal angioplasty (PTA) was considered as the first-line vascular procedure. Factors associated with successful PTA were sought.

RESEARCH DESIGN AND METHODS

In 32 consecutive diabetic patients with foot ulcers and severe limb ischemia, PTA was performed if feasible; if not, primary bypass grafting was done when feasible. All patients were followed until healing or for at least one year. Patients with worsening ulcers after PTA underwent bypass grafting. Clinical and angiographic factors influencing outcomes after PTA were sought by univariate and multivariate analysis.

RESULTS

PTA was done in 25 of the 32 (78%) patients, and considered clinically successful in 13 (52%). After 1 year, the healing rate was 70% and the limb salvage rate 90%. Successful PTA was significantly associated with a higher post-PTA transcutaneous oxygen pressure (P = 0.03) and presence of at least one patent pedal vessel (P = 0.03) in the univariate analysis; only a patent pedal vessel was significant in the multivariate analysis.

CONCLUSION

Primary PTA in diabetic patients with severe ischemic foot ulcers provides similar outcomes to usual results obtained in severe ischemia in absence of diabetes. The presence of one patent pedal vessel on arteriography before PTA is the best prognostic factor.

When is a more proximal amputation needed?

Amputation may be the most appropriate therapy for an ischemic or infected limb, but the level at which to amputate is often difficult to determine. Selecting the appropriate level is crucial when performing an amputation. The goals of surgery are to maintain maximal limb length and ensure successful healing. When more of the foot and limb can be preserved, the chances for rehabilitation are improved. This article reviews how to determine the most appropriate level of amputation.

A retrospective study of patients with diabetes mellitus after partial foot amputation and hyperbaric oxygen treatment

A retrospective chart review was conducted of 35 patients (40 feet) who received hyperbaric oxygen (HBO) therapy after partial foot amputation between 1990 and 2000. Preoperative transcutaneous partial pressure of oxygen (tcPO2) levels, the number of hyperbaric treatments, time to final outcome, use of revascularization procedures, and postsurgical outcome were extracted from the charts. Seventy percent (n = 28) had a successful outcome, defined as complete healing and absence of ulceration at the amputation site, and lack of further surgical procedures to heal the amputation site; whereas 30% (n = 12) had a failed outcome, defined as lack of healing or the presence of an ulcer at the site of amputation or the need for further surgery to heal the amputation site. The level of amputation, use of revascularization procedures, time to final outcome, and number of hyperbaric treatments were not significantly different (P > .05) between the 2 postsurgical outcome groups. The mean preoperative tcPO2 levels were greater (P < .01) in the successful (24 +/- mm Hg) than in the failed (11 +/- mm Hg) outcome groups. All patients with a tcPO2 level > 29 mm Hg had a successful outcome. Patients with a successful postsurgical outcome had a mean of 20 HBO treatments and took 44 days to final outcome, while those with a failed postsurgical outcome had 16 HBO treatments and took 216 days to final outcome.

Transcutaneous partial pressure of oxygen after surgical wounds

Transcutaneous partial pressure of oxygen (TcPO2) predicts wound healing in critical ischemia. However, no studies have controlled for the effect of wounds on TcPO2. In this study, in 24 hip or knee arthroplasty cases without vascular disease, TcPO2 was measured preoperatively at the incision site, contralaterally, and at a reference site on the chest wall. The measurements were repeated at 2 days and 2 months postoperatively and compared. TcPO2, normal preoperatively, decreased at all sites on the second postoperative day (p < 0.001), with a trend toward a greater decrease at the wound (p = 0.09). All wounds healed, and TcPO2 returned to baseline at all sites 2 months postoperatively. In conclusion, acute surgical wounds are associated with a significant and widespread decrease in cutaneous TcPO2 in the setting of normal arterial perfusion. This decrease is likely multifactorial and deserves further investigation.

Arterial injuries: a sonographic approach

Acute arterial emergencies can arise from direct traumatic injury to the artery or be spontaneous. This article emphasizes the various presentations of arterial emergencies. These include acute arterial occlusions; excessive bleeding; and hematoma formation caused by penetrating arterial wall injuries, pseudoaneurysms, and arteriovenous fistulas. The broad category of arterial occlusions includes traumatic lacerations, embolizations, and arterial dissections. Modern ultrasound equipment is a rapid and convenient imaging approach in many of these clinical scenarios. In combination with MR angiography and CT angiography, these noninvasive tests can diagnose the presence of most arterial injuries, and be used to measure their impact.

Electrotherapy reverses inframalleolar ischemia: a retrospective, observational study

OBJECTIVE

To determine if high-voltage pulsed current (HVPC) augments ischemic wound healing and increases periwound perfusion.

DESIGN

A 5-year, retrospective, observational study was conducted on successive patients with ischemic wounds who were poor candidates for revascularization.

INTERVENTION

HVPC was applied directly to wounds at greater than 100 volts, 100 pulses per second, 1 hour per day. In addition to HVPC, patients received standard care for ischemic wounds at the study facility. Ischemic wounds for which HVPC was not clinically indicated or not available received standard care alone.

MAIN OUTCOME MEASURES

Wound area measured by planimetry, wound appearance observed by digital imaging techniques, and microcirculation monitored by transcutaneous oxygen (TcPo(2)) levels.

RESULTS

The group that received HVPC plus standard care showed smaller wound areas from weeks 20 though 52 after the start of treatment compared with the group that received standard care alone (P <.05; Mann-Whitney test). One year after the start of treatment, 90% of HVPC-treated wounds were healed, compared with 29% of the wounds that received only standard care (P <.05; Fisher exact test). For the HVPC group, maximum periwound TcPo(2) improved during electrotherapy (6 +/- 8 mm Hg [standard deviation; SD] at baseline improved to 26 +/- 20 SD, during HVPC, P <.05; Wilcoxon signed rank test).

CONCLUSION

The results of this retrospective trial demonstrate that HVPC plus standard care improved the healing rate of high-risk ischemic wounds. A direct relationship was shown between improved healing rates and increased periwound perfusion. A prospective randomized controlled trial is needed to further support these observational, preliminary findings.

More than one way to measure a wound: an overview of tools and techniques

PURPOSE

To improve clinical practice and the quality of patient care by providing a learning opportunity that enhances the participant's understanding of the tools and techniques available for wound measurement.

TARGET AUDIENCE

This CME/CE activity is intended for physicians and nurses with an interest in learning about tools and techniques available for wound measurement.

OBJECTIVES

After reading the article and taking the test, the participant will be able to: Identify advantages and disadvantages of various dimensional methods used to measure wounds. Identify advantages and disadvantages of visual and photographic assessment methods. Identify advantages and disadvantages of vascular and pressure assessment methods.

Electrotherapy reoxygenates inframalleolar ischemic wounds on diabetic patients: a case series

OBJECTIVE

To retrospectively evaluate the ability of high voltage pulsed current (HVPC) to increase microcirculation in critically ischemic wounds (transcutaneous oxygen [TcPO(2)] less than 10 mm Hg) and, as a result, to improve wound healing.

DESIGN AND METHODS

Clinical case series with successive adult diabetic subjects (3 men and 3 women) with nonsurgical ischemic malleolar or inframalleolar skin lesions, each subject serving as his or her own control. Wound area and TcPO(2) were measured periodically. Presence of distal arteriosclerosis was assessed on 5 patients by 2-dimensional, time-of-flight magnetic resonance angiography. End point was either complete wound closure or leg amputation.

RESULTS

Maximum mean TcPO(2) was 2 +/- 2 mm Hg at the wound edge before the start of electrotherapy. After electrotherapy began, maximum TcPO(2) was 33 +/- 18 mm Hg (N=6; P<.05, Wilcoxon signed rank test). After treatment with HVPC, 4 patients' wounds healed and 2 patients underwent amputation. As expected, healed patients initially deteriorated after the start of treatment, but their wounds began healing when the perilesion TcPO(2) measurement exceeded 20 mm Hg. Thereafter, the wounds closed at a predictable rate. Complete closure occurred for patients who had a relatively low atherosclerotic burden.

CONCLUSION

The results of this clinical case series suggest that electrotherapy can improve periwound microcirculation of ischemic inframalleolar skin lesions.

Intermittent pneumatic compression for the treatment of lower extremity arterial disease: a systematic review

This study aimed to identify the role of intermittent pneumatic compression in treating peripheral arterial disease and to investigate the types of treatment programs that are most effective. Data was sourced from English-language articles which were identified by a computer search using MEDLINE from 1966 to 2001, followed by extensive bibliography review. Studies were included if they contained pertinent material involving a compression device and arterial flow dynamics in lower limbs. A total of 26 English-language studies were identified that met the inclusion criteria. The diverse patient criteria and methods used in the studies provided an opportunity to examine the effectiveness of each, but made it difficult to compare one study with another. To assist in focusing on overall trends in improvement, patient type and treatment type disparities must be identified. In conclusion, it is evident that an intermittent pneumatic compression program appears promising and may be used in patients with severe peripheral arterial disease who are not candidates for revascularization using surgery or percutaneous angioplasty. It is now the goal to establish randomized, prospective, controlled trials to clarify the most beneficial regimen for treating such disease.

Classification of wounds of the diabetic foot

A classification system should be thought of as a diagnostic language. Ideally, this language should be used by a large, diverse population of clinicians to guide therapy and ultimately predict outcome. The diabetic foot ulcer is widely known to be the prime precipitant of lower extremity amputations. Its description and classification is the first step toward widespread standardization of treatment and prevention. This article chronologically describes the major diabetic foot wound classification systems devised over the previous generation, discussing each of their attributes and their shortcomings, with an emphasis on an evidence basis for care. It is our hope that discussions such as this one will ultimately lead to a diagnostic and therapeutic lingua franca for diabetic foot wounds and a commensurate reduction in the unconscionably high prevalence of amputations, which we now currently face.

Transcutaneous oxygen measurements: implications for nursing

Transcutaneous oxygen measurement is a noninvasive diagnostic technique that records the partial pressure of oxygen at the skin surface. This measurement provides information regarding the supply and delivery of oxygen to the underlying microvascular circulation. It can be used for adults in wound evaluation, hyperbaric therapy, plastic surgery, amputation level determination, and peripheral vascular disease assessment, including the status of limb revascularization procedures. This article presents an overview of transcutaneous oxygen measurement and situations that influence measurement levels, including environmental, dermal, physiologic, and mechanical factors. Nursing considerations and indications for further research are also discussed.

Circulator boot therapy alters the natural history of ischemic limb ulceration

Despite numerous advances in interventional radiology and vascular surgery, the clinician continues to be confronted with inoperable vascular disease. Previous studies have shown that ulceration associated with a transcutaneous oxygen pressure (tcPO2) of <20 mmHg is refractory to all attempts at healing. External pneumatic compression for the treatment of peripheral vascular disease has been available for several years, although there is a relative paucity of data regarding its role in clinical practice as well as its efficacy. The objective of this study was to examine the experience with circulator boot therapy in the treatment of ischemic ulcers in the absence of osteomyelitis, and specifically to determine whether such therapy can be of benefit in ischemic limb ulceration associated with a tcPO2 of <20 mmHg. A retrospective chart review was undertaken of ail patients with a lower limb ulcer who, in the absence of osteomyelitis, underwent circulator boot therapy at the Gonda Vascular Center. A total of 98 patients was identified. Two patients died within 1 month of commencing therapy and were not included in further analysis. The tcPO2 data were unavailable in five patients. Outcome in the patient population was classified as favorable if (1)healing was achieved, (2)the ulcer decreased in size, or (3) the affected limb improved sufficiently to allow successful revascularization. An unfavorable outcome was one where a major amputation was performed or where the ulcer increased in size. Out of a total of 29 patients with a tcPO2 <20 mmHg at the area of ulceration, 19 had a favorable outcome following circulator boot therapy. Of the remaining 62 patients with a tcPO2 >20 mmHg, 54 had a favorable outcome. Circulator boot therapy is associated with improved outcomes in limb ulceration due to peripheral vascular disease. Complete ulcer healing as well as preservation of the affected limb can be achieved in most cases.

The challenge and importance of defining critical limb ischemia

Patients with critical limb ischemia are at risk of limb loss and have very high cardiovascular and total mortality rates, which are greater than can be accounted for by the usual risk factors for atherosclerosis. A definition of critical ischemia is necessary to determine the natural history of the disease and to assess and compare the efficacy of various forms of therapy. The definition needs to be based on hemodynamic criteria because clinical manifestations and outcomes are not reliable. The reasons for the difficulties in arriving at a generally acceptable definition are explored. Building on the previous work of others, modified hemodynamic definitions for critical and subcritical ischemia, which include measurements of pressures and of indices of microcirculation, are proposed.

Classification of diabetic foot wounds

Foot ulcers in persons with diabetes are one of the most common precursors to lower extremity amputation. Appropriate care of the diabetic foot ulceration requires a clear, descriptive classification system that may be used to direct appropriate therapy and possibly predict outcome. Ideally, this system would be used by all participants in a multidisciplinary limb salvage team. We describe a clinical classification system for diabetic foot wounds that evaluates wound depth, the presence of infection, and peripheral arterial occlusive disease in every category of the wound assessment. The goal of this system is to improve communication, leading to a less complex, more predictable treatment course and, ultimately, an improved result.

TcPO2 as an accurate predictor of therapy in limb salvage

One hundred forty-seven consecutive patients with limb-threatening acute diabetic pedal sepsis and/or chronic ischemia (Fontaine III/IV) were prospectively studied. Forty-four with palpable pulses underwent successful surgery (major or minor amputation, incision, and drainage) without further evaluation; 103 with decreased or absent pulses had baseline TcPO2 measurements. Fourteen patients with values > or = 30 mm Hg underwent major or minor amputation with 91% (13 of 14) healing success. Ninety patients with values < 30 mm Hg underwent arteriography with 98% (87 of 89) showing significant disease. Of these, 22 did not undergo revascularization and only 50% (11 of 22) showed primary healing following minor amputation or debridement. Sixty-seven patients underwent 74 revascularization procedures; 95% (64 of 67) showed improvement of TcPO2 > 30 mm Hg and of these, 91% (58 of 64) had healing of minor amputation or debridement sites (p < 0.05). TcPO2 measurements may be used to direct therapy because they have been shown to accurately predict the presence of significant vascular disease, its appropriate correction by means of revascularization, and the success of major or minor amputations with or without revascularization.

Elective foot and ankle surgery in the diabetic patient

The philosophy of treating diabetic foot pathology has changed dramatically throughout the years. No longer are old, unfounded fears considered the standard of care. The authors enumerate on their indications and goals of treating this complex entity. Clinical aids, as well as patient evaluations are discussed.

Infrainguinal revascularization in the diabetic patient

This article reviews the epidemiological, anatomical and physiological background to infrainguinal arterial reconstruction in the diabetic patient. There is no firm evidence in the literature for the existence of a surgically significant occlusive 'small-vessel' disease in diabetic patients, either as an aetiological component in the pathogenesis of diabetic foot lesions or as a factor limiting the success of infrainguinal bypass grafting. Recent published results of infrainguinal vascular reconstruction in patients with diabetes are reviewed. These are encouraging; early aggressive treatment of lower-limb occlusive disease may be warranted in the diabetic patient.