Skin perfusion pressure of the foot is a good substitute for toe pressure in the assessment of limb ischemia

Analysis of repeated lesions after diabetic forefoot amputation

AIM

This study was performed to analyze the clinical characteristics, related factors, and prognosis of repeated lesions after diabetic forefoot amputation.

METHODS

The medical records of 998 patients who underwent forefoot amputation because of their diabetic feet from March 2002 to February 2021 were retrospectively analyzed. Of the 508 selected patients with a follow-up period of at least 6 months, 288 had repeated lesions in the forefoot, and 220 did not have repeated lesions. The related factors of repeated lesions were compared and analyzed. Of the patients with repeated lesions, 142 and 104 on the ipsilateral and contralateral sides, respectively were also compared and examined.

RESULTS

Repeated lesions were statistically significant in diabetic polyneuropathy, vascular calcification, and dialysis. However, the anatomical positions of diabetic foot lesions, causes of lesions, anatomical amputation levels, number of surgeries, and management duration had no significant differences. Contralateral lesions occurred 8 months later than ipsilateral lesions, but reamputation above the Lisfranc joint was more frequent and prognosis was poorer.

CONCLUSIONS

Repeated lesions were affected by general conditions, and the contralateral side must be carefully examined after diabetic forefoot amputation.

Phase I/IIa Feasibility Trial of Autologous Quality- and Quantity-Cultured Peripheral Blood Mononuclear Cell Therapy for Non-Healing Extremity Ulcers

Non-healing wounds are among the main causes of morbidity and mortality. We recently described a novel, serum-free ex vivo expansion system, the quantity and quality culture system (QQc), which uses peripheral blood mononuclear cells (PBMNCs) for effective and noninvasive regeneration of tissue and vasculature in murine and porcine models. In this prospective clinical study, we investigated the safety and efficacy of QQ-cultured peripheral blood mononuclear cell (MNC-QQ) therapy for chronic non-healing ischemic extremity wounds. Peripheral blood was collected from 9 patients with 10 chronic (>1 month) non-healing wounds (8 males, 1 female; 64-74 years) corresponding to ischemic extremity ulcers. PBMNCs were isolated and cultured using QQc. Within a 20-cm area surrounding the ulcer, 2 × 107 cells were injected under local anesthesia. Wound healing was monitored photometrically every 2 weeks. The primary endpoint was safety, whereas the secondary endpoint was efficacy at 12-week post-injection. All patients remained ambulant, and no deaths, other serious adverse events, or major amputations were observed for 12 weeks after cell transplantation. Six of the 10 cases showed complete wound closure with an average wound closure rate of 73.2% ± 40.1% at 12 weeks. MNC-QQ therapy increased vascular perfusion, skin perfusion pressure, and decreased pain intensity in all patients. These results indicate the feasibility and safety of MNC-QQ therapy in patients with chronic non-healing ischemic extremity wounds. As the therapy involves transplanting highly vasculogenic cells obtained from a small blood sample, it may be an effective and highly vasculogenic strategy for limb salvage.

Single versus Multiple Vessel Endovascular Tibial Artery Revascularization for Critical Limb Ischemia: A Review of the Literature

Vascular interventionalists have long debated on whether one or multiple patent tibial arteries (run-off) are necessary to treat critical limb ischemia, including ischemic rest pain and tissue loss. This review article seeks to clarify data surrounding this topic by including literature from retrospective studies, prospective studies, meta-analyses, and randomized controlled trials. Our conclusion is that revascularizing a single tibial artery to the foot is adequate for wound healing.

Relationship of Sarcopenia with Microcirculation Measured by Skin Perfusion Pressure in Patients with Type 2 Diabetes

BACKGROUND

Few studies have examined the relationship of sarcopenia with the microcirculation. The current study investigated the relationship of sarcopenia with microcirculatory function, as assessed by skin perfusion pressure (SPP), in type 2 diabetes mellitus (T2DM) patients.

METHODS

In total, 102 T2DM patients who underwent SPP measurements and bioelectrical impedance analysis (BIA) were enrolled in this cross-sectional study. SPP was assessed using the laser Doppler technique. Sarcopenia was defined as low height-adjusted appendicular muscle mass (men, <7 kg/m2; women, <5.7 kg/m2) using BIA. We divided the participants into two groups based on SPP (≤50 and >50 mm Hg), and an SPP below 50 mm Hg was considered to reflect impaired microcirculation.

RESULTS

Fourteen patients (13.7%) were diagnosed with impaired microcirculatory function of the lower limb based on SPP. The prevalence of sarcopenia in all subjects was 11.8%, but the percentage of patients with an SPP ≤50 mm Hg who had sarcopenia was more than triple that of patients with an SPP >50 mm Hg (28.6% vs. 9.1%, P=0.036). A significant positive correlation was found between SPP and appendicular muscle mass adjusted for height (P=0.041 for right-sided SPP). Multiple logistic regression analysis showed that patients with sarcopenia had an odds ratio of 4.1 (95% confidence interval, 1.01 to 24.9) for having an SPP ≤50 mm Hg even after adjustment for confounding factors.

CONCLUSION

These results suggest that sarcopenia may be significantly associated with impaired microcirculation in patients with T2DM. Nonetheless, the small number of patients and wide CI require cautious interpretation of the results.

Vascular Assessment of the Lower Extremity with a Chronic Wound

Peripheral arterial disease (PAD) affects many individuals worldwide and is associated with increased morbidity and mortality. Controversy exists on whether or not to screen asymptomatic patients. Further complicating this is that many patients with a chronic lower extremity wound are often asymptomatic. PAD and traditional noninvasive vascular studies may be inaccurate in providing a correct diagnosis. A review of current and novel vascular assessment modalities along with their benefits and limitations are presented here. A combination of these vascular assessments may help improve accuracy in diagnosis, providing timely care to those patients in need.

Laser Doppler blood flowmeter as a useful instrument for the early detection of lower extremity peripheral arterial disease in hemodialysis patients: an observational study

BACKGROUND

A simpler method for detecting atherosclerosis obliterans is required in the clinical setting. Laser Doppler flowmetry (LDF) is easy to perform and can accurately detect deterioration in skin perfusion. We performed LDF for hemodialysis patients to determine the correlations between blood flow in the lower limbs and peripheral arterial disease (PAD).

METHODS

This retrospective study included 128 hemodialysis patients. Patients were categorized into the non-PAD group (n = 106) and PAD group (n = 22), 14 early stage PAD patients were included in the PAD group. We conducted LDF for the plantar area and dorsal area of the foot and examined skin perfusion pressure (SPP) during dialysis.

RESULTS

SPP-Dorsal Area values were 82.1 ± 22.0 mmHg in the non-PAD, and 59.1 ± 20.3 mmHg in PAD group, respectively (p < 0.05). The LDF-Plantar blood flow (Qb) values were 32.7 ± 15.5 mL/min in non-PAD group and 21.5 ± 11.3 mL/min in PAD group (p < 0.001). A total of 21 non-PAD patients underwent LDF before and during dialysis. The LDF-Plantar-Qb values were 36.5 ± 17.6 mL/min before dialysis and 29.6 ± 17.7 mL/min after dialysis (p < 0.05). We adjusted SPP and LDF for PAD using logistic regression, SPP-Dorsal-Area and LDF-P were significantly correlated with PAD (p < 0.05). The receiver-operating characteristic curve analysis indicated cut-off values of 20.0 mL/min for LDF-Plantar-Qb during dialysis.

CONCLUSION

LDF is a simple technique for sensitive detection of early-stage PAD. This assessment will help physicians identify early-stage PAD, including Fontaine stage II in clinical practice, thereby allowing prompt treatment.

Perfusion Assessment in Critical Limb Ischemia: Principles for Understanding and the Development of Evidence and Evaluation of Devices: A Scientific Statement From the American Heart Association

There are >12 million patients with peripheral artery disease in the United States. The most severe form of peripheral artery disease is critical limb ischemia (CLI). The diagnosis and management of CLI is often challenging. Ethnic differences in comorbidities and presentation of CLI exist. Compared with white patients, black and Hispanic patients have higher prevalence rates of diabetes mellitus and chronic renal disease and are more likely to present with gangrene, whereas white patients are more likely to present with ulcers and rest pain. A thorough evaluation of limb perfusion is important in the diagnosis of CLI because it can not only enable timely diagnosis but also reduce unnecessary invasive procedures in patients with adequate blood flow or among those with other causes for ulcers, including venous, neuropathic, or pressure changes. This scientific statement discusses the current tests and technologies for noninvasive assessment of limb perfusion, including the ankle-brachial index, toe-brachial index, and other perfusion technologies. In addition, limitations of the current technologies along with opportunities for improvement, research, and reducing disparities in health care for patients with CLI are discussed.

Utility of skin perfusion pressure values with the Society for Vascular Surgery Wound, Ischemia, and foot Infection classification system

OBJECTIVE

The addition of skin perfusion pressure (SPP) might enhance the predictive value of the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) classification system. The purpose of the present study was to evaluate the SPP for each WIfI classification stage among patients with foot wounds by cross-referencing the results of prospectively monitored limb outcomes and to derive the SPP criteria that could be combined with other measurements to grade ischemia for the WIfI classification.

METHODS

From July 2015 to June 2017, patients with foot wounds that met the WIfI classification criteria were prospectively enrolled. We assessed the limbs using the WIfI ischemia grade without measuring the transcutaneous oxygen pressure but measured the SPP. After monitoring for 1 year, the predictability of the WIfI stages was analyzed according to whether the limbs had not healed (unchanged or worsened wounds, minor or major amputation, all-cause death) or had healed (improved or healed wounds) by comparing stages 1 and 2 with stages 3 and 4. We also statistically analyzed the SPP values that could be the boundary values between each ischemia grade and reevaluated the predictability of the WIfI stages with the boundary SPP values.

RESULTS

We enrolled a total of 91 limbs for 76 patients (mean age, 70.5 ± 12.0 years). The mean SPP values stratified by ischemia grade 0 to 3 were 52.1, 41.1, 27.1, and 18.8 mm Hg, respectively (an SPP of <30 mm Hg indicates severe ischemia). After monitoring for 1 year, 19 of 48 limbs in stage 1 and 2 and 35 of 43 in stage 3 and 4 were in the nonhealed group and 29 limbs in stage 1 and 2 and 8 limbs in stage 3 and 4 were in the healed group. The SPP boundary values between each ischemia (I) grade were calculated as 45 mm Hg for I-0/I-1, 35 for I-1/I-2, and 25 for I-2/I-3. When jointly using the boundary SPP values, the ischemia grade changed for 23 limbs, altering the distribution of the WIfI stages and limb outcomes: 11 of 38 limbs in stage 1 and 2 and 43 of 53 in stage 3 and 4 were transferred to the nonhealed group. The sensitivity, efficiency, and negative predictive value of WIfI staging improved when staging with SPP: from 65% to 80%, 70% to 77%, and 60% to 71%, respectively.

CONCLUSIONS

The SPP boundary values that could be used with ischemia grade in the WIfI classification were identified as 45, 35, and 25 mm Hg. The addition of SPP could improve the accuracy of the evaluation.

Laser speckle flowgraphy can also be used to show dynamic changes in the blood flow of the skin of the foot after surgical revascularization

Objectives

Laser speckle flowgraphy is a new method that enables the rapid evaluation of foot blood flow without contact with the skin. We used laser speckle flowgraphy to evaluate foot blood flow in peripheral arterial disease patients before and after surgical revascularization.

Materials and methods

A prospective single-center study. Thirty-one patients with 33 limbs that underwent surgical revascularization for peripheral arterial disease were included. Pre- and postoperative foot blood flows were measured on the plantar surface via laser speckle flowgraphy and skin perfusion pressure. The laser speckle flowgraphy device was used to visualize the blood flow distribution of the target skin and processed the pulse wave velocity of synchronized heart beats. The mean blood flow, which was expressed as the area of the pulse wave as the beat strength of skin perfusion on laser speckle flowgraphy converted into a numerical value, was assessed as dynamic changes following surgery. Beat strength of skin perfusion was also investigated in non-peripheral arterial disease controls (23 patients/46 limbs).

Results

The suitability of beat strength of skin perfusion in non-peripheral arterial disease controls was achieved; the beat strength of skin perfusion value was significantly higher in every area of interest in non-peripheral arterial disease controls compared to that in peripheral arterial disease limbs at the preoperative stage (105.8 ± 8.2 vs. 26.3 ± 8.2; P < 0.01). Although the pulse wave before surgery was visually flat in peripheral arterial disease patients, the pulse wave was remarkably and immediately improved through surgical revascularization. Beat strength of skin perfusion showed a dynamic change in foot blood flow (26.3 ± 8.2 at preoperation, 98.5 ± 6.7 immediately after surgery, 107.6 ± 5.7 at seven days after surgery, P < 0.01 for each compared to preoperation) that correlated with an improvement in skin perfusion pressure.

Conclusions

Laser speckle flowgraphy is a noninvasive, contact-free modality that is easy to implement, and beat strength of skin perfusion is a useful indicator of foot circulation during the perioperative period. Further analysis with a larger number of cases is necessary to establish appropriate clinical use.

Skin Perfusion Pressure and Wound Closure Time in Lower Extremity Wounds

Introduction

Peripheral Arterial Disease (PAD) affects approximately 8 million patients in the United States. We investigate the relationship of Skin Perfusion Pressure (SPP) and wound closure time in lower extremity wounds.

Methods

We conducted a retrospective study of 1125 lower extremity wounds in 998 patients between June 2006 and October 2014 in our wound clinic. We analyzed the relationship between SPPand wound closure time. SPP was measured using a Laser Doppler instrument.

Results

Patients with SPP values over 30 mmHg had shorter wound closure times, while patients with SPP values below 30 mmHg had a significantly longer wound closure time. Diabetic patients took longer to achieve wound closure compared to non-diabetics. No significant relationship was observed between SPP and wound closure time in relation to age or gender.

Conclusion

SPP is a useful tool in estimating time to wound closure and assessing the necessity of vascular interventions in lower extremity wounds.

Increase in skin perfusion pressure predicts amputation-free survival after lower extremity bypass surgery for critical limb ischemia

The objective of this study was to determine how postoperative skin perfusion pressure (SPP) as a measure of blood flow after revascularization affects limb prognosis in patients with critical limb ischemia (CLI). We retrospectively reviewed 223 consecutive bypass surgery cases performed in 192 patients with CLI during a 10-year period. SPP was measured 1–2 weeks before and after the procedure. An SPP of 40 mmHg was set as the cut-off value for revascularization. Patients were grouped according to their postoperative SPPs, and amputation-free survival (AFS) was analyzed. An SPP of ≥ 40 mmHg was recovered in 75% of the patients, but no significant difference was found between this group and the group that did not reach 40 mmHg. On the other hand, the values increased by ≥ 20 mmHg from the preoperative values in 70% of the patients. This group had a significantly better AFS than the group that did not increase by 20 mmHg. Logistic regression analysis revealed that (1) a preoperative SPP of < 20 mmHg and (2) a high serum albumin level (> 3.0 g/dL) were significant factors in increasing SPP by 20 mmHg. These results showed that an increase in SPP of ≥ 20 mmHg after bypass surgery was associated with better limb prognosis.

Contemporary critical limb ischemia: Asian multidisciplinary consensus statement on the collaboration between endovascular therapy and wound care

The burden of peripheral artery disease (PAD) and diabetes in Asia is projected to increase. Asia also has the highest incidence and prevalence of end-stage renal disease (ESRD) in the world. Therefore, most Asian patients with PAD might have diabetic PAD or ESRD-related PAD. Given these pandemic conditions, critical limb ischemia (CLI) with diabetes or ESRD, the most advanced and challenging subset of PAD, is an emerging public health issue in Asian countries. Given that diabetic and ESRD-related CLI have complex pathophysiology that involve arterial insufficiency, bacterial infection, neuropathy, and foot deformity, a coordinated approach that involves endovascular therapy and wound care is vital. Recently, there is increasing interaction among cardiologists, vascular surgeons, radiologists, orthopedic surgeons, and plastic surgeons beyond specialty and country boundaries in Asia. This article is intended to share practical Asian multidisciplinary consensus statement on the collaboration between endovascular therapy and wound care for CLI.

Skin perfusion pressure as a predictor of ischemic wound healing potential

Skin perfusion pressure (SPP) is the blood pressure that is the requisite for the restoration of microcirculatory or capillary flow following controlled occlusion and subsequent flow return. The purpose of the current review was to evaluate the value of SPP for the prediction of wound healing in patients with limb ischemia. Articles published up to January 31, 2017 were searched in the PubMed database and Chinese database CNKI, using the keywords of 'skin perfusion pressure', 'limb ischemia' and 'wound healing'. Articles were obtained and reviewed to analyze the predictive value of SPP with regard to the healing potential of ischemia wounds on limbs. Three different types of techniques are currently used for the measurement of SPP, namely radioisotope clearance, photoplethysmography and laser Doppler, with laser Doppler as the most widely applied technique, due to its noninvasiveness and ease of operability. SPP may effectively assess wound healing potential in ischemic limbs with high sensitivity and specificity; however, its optimum cut-off point remains uncertain. Compared with other noninvasive microcirculatory assessment tools including ankle-brachial index, toe blood pressure and transcutaneous oxygen pressure, SPP has its advantages including that it is not affected by vascular calcification, anatomical structure or patient condition. In conclusion, SPP may be used as an index to accurately predict wound healing in patients with limb ischemia. However, it is difficult to determine the optimum cut-off of SPP due to the limitations of current data. Further study is necessary to confirm the optimum cut-off value of SPP in predicting wound healing potential.

Subjecting the ankle-brachial index to timely scrutiny: is it time to say goodbye to the ABI?

Although the ankle-brachial index (ABI) has been used as an indicator of peripheral artery disease and vascular supply to the foot for over 50 years, it is now associated with reservations and qualifying empirical evidence to the extent that the provocative step of abandoning it totally might be advisable. In this article, the results of three publications concerning the ABI are initially described in some depth and the results from eight additional publications are then summarized more briefly. Cumulatively, the research indicates that ABIs that seem to be normal, as well as those in the subnormal range, are often inflated by medial arterial calcification and can therefore produce a high proportion of false-negative screening test results for arterial disease as well as a misleadingly high impression of vascular sufficiency to the lower extremity. The toe-brachial index is suggested as being likely to overcome the problems associated with the ABI, and other alternatives to the ABI and TBI are acknowledged.

Skin perfusion pressure as an indicator of tissue perfusion in valvular heart surgery: Preliminary results from a prospective, observational study

Hemodynamic management aims to provide adequate tissue perfusion, which is often altered during cardiac surgery with cardiopulmonary bypass (CPB). We evaluated whether skin perfusion pressure (SPP) can be used for monitoring of adequacy of tissue perfusion in patients undergoing valvular heart surgery. Seventy-two patients undergoing valve replacement were enrolled. SPP and serum lactate level were assessed after anaesthesia induction (baseline), during CPB, after CPB-off, end of surgery, arrival at intensive care unit, and postoperative 6 h. Lactate was further measured until postoperative 48 h. Association of SPP with lactate and 30-day morbidity comprising myocardial infarction, acute kidney injury, stroke, prolonged intubation, sternal infection, reoperation, and mortality was assessed. Among the lactate levels, postoperative 6 h peak value was most closely linked to composite of 30-day morbidity. The SPP value during CPB and its % change from the baseline value were significantly associated with the postoperative 6 h peak lactate (r = -0.26, P = 0.030 and r = 0.47, P = 0.001, respectively). Optimal cut-off of % decrease in SPP during CPB from baseline value for the postoperative 6 h hyperlactatemia was 48% (area under curve, 0.808; 95% confidence interval (CI), 0.652-0.963; P = 0.001). Decrease in SPP >48% during CPB from baseline value was associated with a 12.8-fold increased risk of composite endpoint of 30-day morbidity (95% CI, 1.48-111.42; P = 0.021) on multivariate logistic regression. Large decrease in SPP during CPB predicts postoperative 6 h hyperlactatemia and 30-day morbidity, which implicates a promising role of SPP monitoring in the achievement of optimal perfusion during CPB.

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.

New horizons in the understanding of the causes and management of diabetic foot disease: report from the 2017 Diabetes UK Annual Professional Conference Symposium

Diabetes-related foot disease remains a common problem. For wounds, classic teaching recommends the treatment of any infection, offloading the wound and ensuring a good blood supply, as well as ensuring that the other modifiable risk factors are addressed and optimized. There remain, however, several questions about these and other aspects of the care of diabetes-related foot disease. Some of these questions are addressed in the present report; in particular, the impact of newer technologies in the identification of any organisms present in a wound, as well as the use of novel approaches to treat infections. The use of new remote sensing technology to identify people at risk of developing foot ulceration is also considered, in an attempt to allow early intervention and prevention of foot ulcers. The psychological impact of foot disease is often overlooked, but with an increasing number of publications on the subject, the cause-and-effect role that psychology plays in foot disease, such as ulcers and Charcot neuroarthropathy, is considered. Finally, because of heterogeneity in diabetic foot studies, comparing results is difficult. A recently published document focusing on ensuring a standardized way of reporting foot disease trials is discussed.

A quantitative real-time assessment of Buerger exercise on dorsal foot peripheral skin circulation in patients with diabetes foot

Buerger exercise can improve the peripheral circulation of lower extremities. However, the evidence and a quantitative assessment of skin perfusion immediately after this exercise in patients with diabetes feet are still rare.We recruited 30 patients with unilateral or bilateral diabetic ulcerated feet in Chang Gung Memorial Hospital, Chia-Yi Branch, from October 2012 to December 2013. Real-time dorsal foot skin perfusion pressures (SPPs) before and after Buerger exercise were measured and analyzed. In addition, the severity of ischemia and the presence of ulcers before exercise were also stratified.A total of 30 patients with a mean age of 63.4 ± 13.7 years old were enrolled in this study. Their mean duration of diabetes was 13.6 ± 8.2 years. Among them, 26 patients had unilateral and 4 patients had bilateral diabetes foot ulcers. Of the 34 wounded feet, 23 (68%) and 9 (27%) feet were classified as Wagner class II and III, respectively. The real-time SPP measurement indicated that Buerger exercise significantly increased the level of SPP by more than 10 mm Hg (n = 46, 58.3 vs 70.0 mm Hg, P < 0.001). In terms of pre-exercise dorsal foot circulation condition, the results showed that Buerger exercise increased the level of SPP in severe ischemia (n = 5, 22.1 vs 37.3 mm Hg, P = 0.043), moderate ischemia (n = 14, 42.2 vs 64.4 mm Hg, P = 0.001), and borderline-normal (n = 7, 52.9 vs 65.4 mm Hg, P = 0.028) groups, respectively. However, the 20 feet with SPP levels more than 60 mm Hg were not improved significantly after exercise (n = 20, 58.3 vs 71.5 mm Hg, P = 0.239). As to the presence of ulcers, Buerger exercise increased the level of SPP in either unwounded feet (n = 12, 58.5 vs 66.0 mm Hg, P = 0.012) or wounded feet (n = 34, 58.3 vs 71.5 mm Hg, P < 0.001). The majority of the ulcers was either completely healed (9/34 = 27%) or still improving (14/34 = 41%).This study quantitatively demonstrates the evidence of dorsal foot peripheral circulation improvement after Buerger exercise in patients with diabetes.

Lower limb ischaemia in patients with diabetic foot ulcers and gangrene: recognition, anatomic patterns and revascularization strategies

The confluence of several chronic conditions--in particular ageing, peripheral artery disease, diabetes, and chronic kidney disease--has created a global wave of lower limbs at risk for major amputation. While frequently asymptomatic or not lifestyle limiting, at least 1% of the population has peripheral artery disease of sufficient severity to be limb threatening. To avoid the critical error of failing to diagnose ischaemia, all patients with diabetic foot ulcers and gangrene should routinely undergo physiologic evaluation of foot perfusion. Ankle brachial index is useful when measurable, but may be falsely elevated or not obtainable in as many as 30% of patients with diabetic foot ulcers primarily because of medial calcinosis. Toe pressures and skin perfusion pressures are applicable to such patients.

Mouse Models of Acute Respiratory Distress Syndrome: A Review of Analytical Approaches, Pathologic Features, and Common Measurements

Acute respiratory distress syndrome (ARDS) is a severe pulmonary reaction requiring hospitalization, which is incited by many causes, including bacterial and viral pneumonia as well as near drowning, aspiration of gastric contents, pancreatitis, intravenous drug use, and abdominal trauma. In humans, ARDS is very well defined by a list of clinical parameters. However, until recently no consensus was available regarding the criteria of ARDS that should be evident in an experimental animal model. This lack was rectified by a 2011 workshop report by the American Thoracic Society, which defined the main features proposed to delineate the presence of ARDS in laboratory animals. These should include histological changes in parenchymal tissue, altered integrity of the alveolar capillary barrier, inflammation, and abnormal pulmonary function. Murine ARDS models typically are defined by such features as pulmonary edema and leukocyte infiltration in cytological preparations of bronchoalveolar lavage fluid and/or lung sections. Common pathophysiological indicators of ARDS in mice include impaired pulmonary gas exchange and histological evidence of inflammatory infiltrates into the lung. Thus, morphological endpoints remain a vital component of data sets assembled from animal ARDS models.

Distal bypass to a critically ischemic foot increases the skin perfusion pressure at the opposite site of the distal anastomosis

INTRODUCTION

The purpose of the study was to reveal the effect of blood flow supply to the foot by analyzing the skin perfusion pressure values and the pedal arch connection after bypass surgery.

PATIENTS AND METHODS

We selected 48 operated limbs whose skin perfusion pressure was measured pre- and post-operatively on the opposite site of distal anastomosis. We also assigned the ischemic limbs to three groups according to the patency of the pedal arch: good, intermediate, and poor.

RESULTS

The mean value of skin perfusion pressure increased significantly from 27.0 ± 14.9 to 52.8 ± 16.0 (p < 0.001) post-operatively. Skin perfusion pressure improved in most of the limbs post-operatively and decreased or unchanged in only four limbs, all of which showed improved tissue loss. Three amputated limbs were due to infection, and all showed an increase in skin perfusion pressure.

CONCLUSION

It was difficult to correlate limb prognosis to skin perfusion pressure and the pedal arch connection.

Diagnosis and assessment of peripheral arterial disease in the diabetic foot

Approximately half of all patients with a diabetic foot ulcer have co-existing peripheral arterial disease. Identifying peripheral arterial disease among patients with foot ulceration is important, given its association with failure to heal, amputation, cardiovascular events and increased risk of premature mortality. Infection, oedema and neuropathy, often present with ulceration, may adversely affect the performance of diagnostic tests that are reliable in patients without diabetes. Early recognition and expert assessment of peripheral arterial disease allows measures to be taken to reduce the risk of amputation and cardiovascular events, while determining the need for revascularization to promote ulcer healing. When peripheral arterial disease is diagnosed, the extent of perfusion deficit should be measured. Patients with a severe perfusion deficit, likely to affect ulcer healing, will require further imaging to define the anatomy of disease and indicate whether a revascularization procedure is appropriate.

Poor Prognosis in Critical Limb Ischemia Without Pre-Onset Intermittent Claudication

BACKGROUND

Some patients with critical limb ischemia (CLI) lack symptoms of intermittent claudication (IC) before the onset of CLI. We studied the outcome of such patients, because this is currently unknown. METHODS AND RESULTS: For retrospective exploratory analysis, we divided 225 patients (265 limbs) with CLI into 2 groups: 142 patients (172 limbs) without a history of IC (non-IC group) and 83 patients (93 limbs) with IC (IC group). We examined comorbid factors and found that a higher proportion of patients in the non-IC group failed to undergo arterial revascularization (49% vs. 20%, P<0.0001) due to progressed limb ischemia and infection. We then analyzed 140 patients (161 limbs) with revascularization. Patients in the non-IC group were more likely to have diabetes mellitus (P=0.03), hypoalbuminemia (P=0.02), advanced Rutherford's classification (P=0.0007), worse ambulatory function (P=0.009), and longer postoperative stay (P=0.04). Amputation-free survival was lower in the non-IC group (P=0.005). On Cox regression analysis, hemodialysis (P=0.002), coronary artery disease (P=0.04), cerebrovascular disease (P=0.02), non-ambulatory status (P=0.02), and non-IC (P=0.01) were independent risk factors for lower amputation-free survival.

CONCLUSIONS

Patients without IC before CLI onset have several unique features, and non-IC is an independent risk factor for poor outcome.

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.

Comparison of characteristics and healing course of diabetic foot ulcers by etiological classification: neuropathic, ischemic, and neuro-ischemic type

AIMS

To identify differences in the characteristics of patients with diabetic foot ulcers (DFUs) according to their etiological classification and to compare their healing time.

METHODS

Over a 4.5-year period, 73 patients with DFUs were recruited. DFUs were etiologically classified as being of neuropathic, ischemic, or neuro-ischemic origin. Descriptive analyses were performed to characterize study subjects, foot-related factors, and healing outcome and time. Duration of healing was assessed using the Kaplan-Meier method. Healing time among the three types was compared using the log rank test.

RESULTS

The number of patients manifesting neuropathic, ischemic, and neuro-ischemic ulcers was 30, 20, and 14, respectively. Differences were identified for age, diabetes duration, body mass index, hypertension, and estimated glomerular filtration rate. Patients with neuro-ischemic ulcers had better ankle-brachial index, skin perfusion pressure (SPP), and transcutaneous oxygen pressure values compared to those with ischemic ulcers. The average time in which 50% of patients had healed wounds was 70, 113, and 233 days for neuropathic, neuro-ischemic, and ischemic ulcers, respectively. Main factors associated with healing were age and SPP values.

CONCLUSIONS

Based on the etiological ulcer type, DFU healing course and several patient factors differed. Failure to consider the differences in DFU etiology may have led to heterogeneity of results in previous studies on DFUs.

Skin Perfusion Pressure

Skin perfusion pressure (SPP) is a noninvasive diagnostic test that quantitatively analyzes the local blood flow in an area of interest. SPP is measured using a laser Doppler sensor that is placed under an inflated/deflated blood pressure cuff and is able to detect red blood cell motion in the microcirculation as the cuff pressure passes through systole. The SPP results can be used in conjunction with physiological arterial testing to aid in the diagnosis of critical limb ischemia. The examination also can be a guide in determining the most advantageous level for amputation in patients with critical limb ischemia. SPP provides a measure of the potential for healing or progression of a wound without revascularization.

'Real angiosome' assessment from peripheral tissue perfusion using tissue oxygen saturation foot-mapping in patients with critical limb ischemia

OBJECTIVES

The "tissue oxygen saturation (StO2) foot-mapping" method was developed using a non-invasive near-infrared tissue oximeter monitor to classify the foot regions as ischemic and non-ischemic areas. The purpose of this study was to evaluate StO2 foot-mapping as a reliable method to detect ischemic areas in the feet of patients with critical limb ischemia (CLI), and to compare the results with assessments from the angiosome model.

METHODS

The foot areas of 20 CLI patients and 20 healthy controls were classified into four regions: (1) 0 ≤ StO2 < 30%, (2) 30 ≤ StO2 < 50%, (3) 50 ≤ StO2 < 70%, and (4) 70 ≤ StO2 ≤ 100% to perform StO2 foot-mapping. Each area occupancy rate was compared between the two groups, and the threshold StO2 value for detecting ischemia was set. Next, the locations of ulcers (in 16 patients) were compared to the predicted ischemic regions by the StO2 foot-mapping and by the angiosome model and angiography.

RESULTS

In regions (1) and (2) (StO2 < 50%), the area occupancy rate was significantly higher in the CLI group and almost zero in the control group, so that the threshold StO2 value for detecting ischemia was set at 50%. The locations of ulcers were compatible with StO2 foot-mapping in 87.5% of the cases (14/16), while they were compatible with the assessment from the angiosome model in 68.8% of the cases (11/16).

CONCLUSIONS

This study suggests that StO2 foot-mapping can successfully and non-invasively detect ischemic areas in the peripheral tissue of the foot, and also more appropriately than the assessment provided by the angiosome model. StO2 foot-mapping can be used to evaluate the real angiosome: the real distribution of the peripheral tissue perfusion in the CLI patient's foot, which is determined by the peripheral microvascular blood flow, rather than the main arterial blood flow.

Evaluation of the paramalleolar bypass for critical limb ischemia patients on hemodialysis with diabetes mellitus and chronic renal failure

OBJECTIVE

To assess the influence of diabetes mellitus (DM) and end-stage renal failure on hemodialysis (HD) on the healing time of tissue lesions and blood flow to the foot following a paramalleolar bypass in patients with critical limb ischemia (CLI).

METHODS

Consecutive patients with CLI and tissue loss (24 limbs) were followed up retrospectively after paramalleolar bypass, and the healing time of tissue lesions, graft patency, limb salvage and survival rates were analyzed. The blood flow to the foot was assessed by skin perfusion pressure (SPP) pre- and postoperatively. The delta SPP was calculated as the difference between the SPP before and after bypass. The patients were divided into 3 groups: diabetic (DM, n = 9); diabetic and end-stage renal failure on hemodialysis (HD, n = 10); or neither (n = 5).

RESULTS

A total of 15 dorsal and 9 plantar artery bypasses were performed. The median follow-up was 7.3 months (range, 1-18 months). No patients required major amputations, and all tissue lesions healed. The mean duration to complete tissue healing of the DM, HD and neither groups was 2.2, 2.5 and 1.2 months, respectively, was and these were not statistically significant. A significant improvement in the delta SPP after paramalleolar bypass was observed in the neither group compared with both the DM and HD groups.

CONCLUSION

Blood flow to the foot was not sufficiently improved in CLI patients with DM and HD, despite paramalleolar bypass. This may be the cause of the prolonged tissue healing duration of CLI patients with DM and HD. (English Translation of Jpn J Vasc Surg 2012; 21: 91-95).

Autologous G-CSF-mobilized peripheral blood CD34+ cell therapy for diabetic patients with chronic nonhealing ulcer

Recently, animal studies have demonstrated the efficacy of endothelial progenitor cell (EPC) therapy for diabetic wound healing. Based on these preclinical studies, we performed a prospective clinical trial phase I/IIa study of autologous G-CSF-mobilized peripheral blood (PB) CD34(+) cell transplantation for nonhealing diabetic foot patients. Diabetic patients with nonhealing foot ulcers were treated with 2 × 10(7) cells of G-CSF-mobilized PB CD34(+) cells as EPC-enriched population. Safety and efficacy (wound closure and vascular perfusion) were evaluated 12 weeks posttherapy and further followed for complete wound closure and recurrence. A total of five patients were enrolled. Although minor amputation and recurrence were seen in three out of five patients, no death, other serious adverse events, or major amputation was seen following transplantation. Complete wound closure was observed at an average of 18 weeks with increased vascular perfusion in all patients. The outcomes of this prospective clinical study indicate the safety and feasibility of CD34(+) cell therapy in patients with diabetic nonhealing wounds.

Critical limb ischemia: endovascular strategies for limb salvage

Critical limb ischemia (CLI) represents the most severe clinical manifestation of peripheral arterial disease, defined as the presence of chronic ischemic rest pain, ulcers, or gangrene attributable to objectively proven arterial occlusive disease. The dominant pathology underlying CLI is atherosclerosis, distributed at multiple levels along the length of the lower extremity and with a propensity for involvement of the tibial vessels in the leg and the small vessels of the foot. To achieve limb salvage in patients with CLI, revascularization of the affected limb is generally required. In contemporary practice, endovascular techniques are rapidly replacing surgical bypass as the first option for revascularization for CLI based on high technical success rates and low rates of procedure-related morbidity and mortality. This review will describe the clinical strategy of the authors who have adopted an endovascular-first approach to revascularization in treating patients with CLI and summarize the clinical outcomes of endovascular therapy in this population.

Perfusion pressures and distal oxygenation in individuals with diabetes undergoing chronic hemodialysis

BACKGROUND

The number of diabetic patients worldwide was estimated to be approximately 285 million in 2010. Approximately 5% of all diabetic patients have foot ulcers, often preceded by neuropathy and delayed healing resulting from peripheral vascular disease which leads to increased risk of infection. Additionally, there is a concern that blood flow to the feet may be reduced in patients with diabetes, which may be further compounded by changes in lower extremity perfusion pressure during hemodialysis. Current laser Doppler technology provides the opportunity to identify changes in vascularityin a non-invasive fashion.

MATERIALS AND METHODS

A prospective, parallel-arm, comparison, pilot study was conducted. A total of 15 patients were enrolled, ten of whom had a documented history of diabetes. All patients required hemodialysis. Peripheral perfusion and oxygenation measurements were obtained before, midway and at the conclusion of three separate dialysis sessions within a 3-week interval for each subject.

RESULTS

Preliminary results indicate a significant reduction in toe pressure during and after hemodialysis in the diabetic patient group compared to the non-diabetic group. Significant differences were not found in skin perfusion measurements or in the oxygenation measurements at any time in diabetic and nondiabetic patients undergoing hemodialysis.

CONCLUSION

Preliminary results suggest hemodialysis may significantly affect pressure of the lower extremities in diabetic patients. Trends from these data indicate the need to further investigate the effect of hemodialysis on techniques used to heal wounds and ulcers in patients with diabetes.

A modified transmetatarsal amputation

The incidence of the diabetic foot is increasing worldwide. Because evidence has shown that transmetatarsal amputation is associated with fewer failures in amputations of the diabetic foot with or without peripheral arterial disease, improving its management and surgical technique is a mission for the surgeon. Conventional transmetatarsal amputation has held firm, however, for more than 150 years. With a new concept for the transmetatarsal amputation method aimed at a better outcome, we propose a modified procedure for preserving the soft tissue between the metatarsal bones (the vasculature complex with the muscles, periostea, and vessels) and applying it to the distal bone stumps. The purpose of this method is to secure a functional foot by preserving the longitudinal arch. The new method was applied to 11 patients with diabetes mellitus or peripheral arterial disease, or both. All wounds closed successfully. Of the 11 patients, 8 were still alive with no complications. Of these 8 patients, 6 were able to ambulate with a custom-made shoe and 2 used a wheelchair, just as preoperatively. Of the 3 patients who died, 1 died a natural death, 1 died of sepsis, and 1 of cerebral infarction. We believe that the modified transmetatarsal amputation that we have described in this report is a potential breakthrough in the care of patients with forefoot gangrene and may gain acceptance over time.

Skin Perfusion Pressure is a Useful Tool for Evaluating Outcome of Ischemic Foot Ulcers with Conservative Therapy

OBJECTIVES

This study intended to confirm whether skin perfusion pressure (SPP) could predict the outcome of ischemic wound healing.

PATIENTS AND METHODS

Sixty-two limbs in 53 patients with conservative therapy were enrolled in this study. A SPP value of 40 mmHg was adopted as the criterion for making clinical decisions. The outcome one month after SPP measurement was classified as "improved" (diameter of ulcer decreased ≥ 20% or demarcation of gangrene became well defined) or "no change or worse" (others), and the fate of wound was classified as "healed" or "not healed". The evaluated influential factors on the outcome at one month included age, sex, presence of arteriosclerosis obliterans, collagen disease, hypertension, diabetes mellitus, hemodialysis, wound infection, wound management, and SPP ≥ 40 mmHg.

RESULTS

Using a criterion of SPP ≥ 40 mmHg, the outcome at one month could be predicted with a sensitivity: of 75.0%, a specificity: of 82.6%, and an accuracy: of 80.6%. The receiver operating characteristic curve indicated our criterion to be appropriate. Logistic regression analysis showed SPP ≥ 40 mmHg to be an independent factor (P < 0.0001) with the odds ratio of 14.2 (95% CI 3.6-55.8).

CONCLUSIONS

SPP, using a cutoff value of 40 mmHg, can predict the ischemic wound healing with conservative therapy.

Skin perfusion pressure in chronic venous disorders

OBJECTIVE

To examine whether a patient group with chronic venous disorders (CVDs) would show a different response to a pressure provocation test, such as skin perfusion pressure (SPP) of microcirculatory function.

DESIGN

A cuff inflation technique was applied to the gaiter area of the lower legs to induce complete occlusion of the microcirculation. The cuff was then released to measure the pressure at which perfusion resumed, and SPP was measured with a laser Doppler flowmeter (LDF). The measurements at reperfusion were taken of skin of the lower legs of individuals with CVD and compared with the lower-leg skin of control participants.

MAIN OUTCOME MEASURES

To establish whether a measurable difference in SPP exists between the group with CVD and the group without CVD, the means of 9 measurements taken were compared using the Student t test. The lowest value of the 9 measurements of minimum pressure (LMV) was used to estimate the pressure at which reperfusion occurred (SPP). The means of those estimates were then compared using the Student t test.

MAIN RESULTS

The mean LMV measured in the CVD group was slightly higher than that measured in the group without CVD. Although this could be considered a clinically significant result, it was not statistically different.

CONCLUSIONS

For this study, SPP was not significantly different for those with CVD compared with those without. These results suggest that SPP conducted with an LDF has little potential to detect "invisible" changes in the microcirculatory function of the skin affected by CVDs.

Quantitative assessment of therapeutic effects in the critically ischemic limb using (99m)Tc-diethylene-triamine-pentaacetic acid human serum albumin

PURPOSE

To investigate the reliability and limitations of a new radioisotope method using (99m)Tc-diethylenetriamine-pentaacetic acid human serum albumin (Tc-99m-DTPA-HSA) and to evaluate the diagnostic ability of isotope infusion for assessing hemodynamic changes in the foot before and after treatment.

METHODS

Hemodynamic changes before and after treatment were assessed in 21 limbs with ulcer or gangrene, by analyzing changes in the time-activity curve, the uptake ratio, and the values obtained with noninvasive techniques.

RESULTS

There were significant differences between each pair of the three types of time-activity curve and their uptake counts. The uptake ratio was correlated with ankle blood pressure (ABP) and toe blood pressure (TBP), but not with transcutaneous oxygen pressure (tcPO(2)) or skin perfusion pressure (SPP). The hemodynamic change induced by pharmacotherapy was subtle, but that induced by arterial reconstruction was remarkable. Although there was not always a good correlation between the degree of hemodynamic change and the clinical outcome in limbs treated with pharmacotherapy, the hemodynamic change was quantitatively assessed.

CONCLUSION

Our study suggests that this isotope technique is a useful quantitative method to evaluate hemodynamic change from a different perspective to conventional noninvasive methods.

Ankle Peak Systolic Velocity: New Parameter to Predict Nonhealing in Diabetic Foot Lesions

The objective of this study was to determine whether ankle peak systolic velocity (APSV) can predict nonhealing in diabetic foot lesions. Diabetic patients referred for duplex scanning of the lower extremity arteries were included if they had foot lesions such as ulcers, gangrene, or tissue necrosis and had no palpable pedal pulses. End points were healed or healing foot lesions, revascularization, major amputation, or death. One hundred consecutive limbs were included. Forty-three limbs with diabetic foot lesions reached the end point of adequate healing or complete healing, whereas 57 limbs had nonhealing lesions. The APSV was significantly higher in limbs with healed or healing lesions compared with limbs with nonhealed lesions: 53.0 cm/s (41.8–81.6) versus 19.2 cm/s (12.4–26.5), p < .0001. At a cutoff point of 35 cm/s, the APSV showed a sensitivity of 92.9% (95% confidence interval [CI] 82–97), a specificity of 90.6% (95% CI 76–96), a positive predictive value of 92.9%, and a negative predictive value of 90.6% in predicting nonhealing of diabetic foot lesions. There was a significant difference between the APSV before and after revascularization: 20.4 cm/s (12.4–26.3) versus 48.8 cm/s (36.1–80.8), p < .0001. APSV could predict nonhealing of diabetic foot lesions with a high degree of accuracy in this group of patients.