In Association with Other Risk Factors, Smoking Is the Main Predictor for Lower Transcutaneous Oxygen Pressure in Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) significantly increases the risk of peripheral artery disease (PAD), and diabetes is the leading cause of nontraumatic amputations. This study investigated the risk factors for transcutaneous oxygen pressure (TcPO2) in T2DM, a noninvasive method to quantify skin oxygenation and the underlying microvascular circulation. The study included 119 T2DM patients (91 male/28 female). TcPO2 measurements were conducted with the Tina TCM4 Series transcutaneous monitor (Radiometer, Copenhagen, Sweden) and skin electrodes. Patients with TcPO2 < 40 mmHg were younger (p = 0.001), had significantly higher systolic blood pressure (SBP) (p = 0.023), glycated hemoglobin (HbA1c) (p = 0.013), fasting plasma glucose (fPG) (p = 0.038), total cholesterol (p = 0.006), LDL cholesterol (p = 0.004), and had more frequent smoking habits (p = 0.001) than those with TcPO2 ≥ 40 mmHg. The main predictors for the TcPO2 value (R2 = 0.211) obtained via stepwise regression analysis were age, smoking, SBP, HbA1c, fPG, and total and LDL cholesterol. Among all the listed predictors, smoking, HbA1c, and LDL cholesterol were found to be the most significant, with negative parameter estimates of -3.051310 (p = 0.0007), -2.032018 (p = 0.0003), and -2.560353 (p = 0.0046). The results of our study suggest that in association with other risk factors, smoking is the main predictor for lower TcPO2 in T2DM.

Use of consecutive transcutaneous oxygen measurement when assessing the need for revascularization and association with the outcomes of ischemic diabetic ulcers

This study compared the ankle-brachial index (ABI) with transcutaneous oxygen pressure (TcPO2 ) in assessing peripheral vascular disease (PVD) prevalence in 100 diabetic foot ulcer (DFU) patients. Patients were categorized into vascular or nonvascular reconstruction groups and underwent both ABI and TcPO2 measurements four times over 6 months. Predictive validity for PVD diagnosis was analysed using the area under the receiver-operating characteristic curve (AUC). The study found TcPO2 to be a superior predictor of PVD than ABI. Among the DFU patients, 51 with abnormal TcPO2 values underwent vascular reconstruction. Only TcPO2 values showed significant pretreatment differences between the groups and increased post-reconstruction. These values declined over a 6-month follow-up, whereas ABI values rose. For those with end-stage renal disease (ESRD), TcPO2 values saw a sharp decrease within 3 months. Pre-reconstruction TcPO2 was notably lower in amputation patients versus limb salvage surgery patients. In conclusion, TcPO2 is more effective than ABI for evaluating ischemic limb perfusion and revascularization necessity. It should be prioritized as the primary follow-up tool, especially for ESRD patients.

Correlation of ACR and TcPO2 in diabetic kidney disease patients: A pilot study

OBJECTIVE

Transcutaneous oxygen pressure (TcPO2) is used to assess microcirculation clinically; however, it is not widely available especially in rural hospital. The study was designed to explore potential alternatively biomarkers to assess microcirculation in diabetic kidney disease (DKD).

METHODS

A total of 404 patients from Xuzhou first hospital were recruited according to the case records system. Patients were grouped via the ratio of albuminuria and creatinine (ACR; <30 mg/g, 30-300 mg/g, >300 mg/g). Biomarkers in different ACR groups were compared by analysis of variance. Correlation analysis was determined by Pearson or Spearman analysis and binary logistic regression. The receiver operating characteristics (ROC) curve was performed to elucidate the prediction effect of ACR on TcPO2.

RESULTS

A total of 404 diabetic patients were recruited with 248 patients diagnosed as DKD and 156 non-DKDs. Age and cystatin C were significantly higher in the ACR3 group compared with those in the ACR1 group, whereas glomerular filtration rate, low-density lipoprotein cholesterol, and TcPO2 were markedly decreased in the ACR3 group (p < .05). Frequency of low TcPO2 (<40 mm Hg) was markedly increased as increment of ACR stages with 30.2% in the ACR3 group (p < .01). There was a negative correlation between TcPO2 and age, ACR, chronic kidney disease (CKD), fast blood glucose, diabetes mellitus (DM) duration, and diabetic neuropathy. Further, binary logistic regression showed ACR was an independent influence factor for low TcPO2. After adjusting for age, gender, hypertension, DM duration, body mass index, glycated hemoglobin, diabetic neuropathy, and CKD, ACR was still an independent influence factor for TcPO2 (odds ratio = 2.464, p < .01). The area under the ROC curve was 0.768 (95% confidence interval: 0.700-0.836, p < .001) for ACR. The analysis of ROC curves revealed a best cutoff for ACR was 75.25 mg/g and yielded a sensitivity of 71.7% and a specificity of 71.7%.

CONCLUSIONS

ACR could be used as an alternative biomarker for assessing microcirculation in DKD patients.

Microcirculation Improvement in Diabetic Foot Patients after Treatment with Sucrose Octasulfate-Impregnated Dressings

To assess the patients' microcirculation evolution during the treatment with a sucrose octasulfate-impregnated dressing, fifty patients with neuroischaemic DFU treated with TLC-NOSF dressing were included in a prospective study between November 2020 and February 2022. TcpO₂ values were measured on the dorsalis pedis or tibial posterior arteries' angiosome according to the ulcer location. TcpO₂ values were assessed at day 0 and every 4 weeks during 20 weeks of the follow-up or until the wound healed. A cut-off point of tcpO₂ < 30 mmHg was defined for patients with impaired microcirculation. The TcpO₂ values showed an increase between day 0 and the end of the study, 33.04 ± 12.27 mmHg and 40.89 ± 13.06 mmHg, respectively, p < 0.001. Patients with impaired microcirculation showed an increase in the tcpO₂ values from day 0 to the end of the study (p = 0.023). Furthermore, we observed a significant increase in the TcpO₂ values in the forefoot DFU (p = 0.002) and in the rearfoot DFU (p = 0.071), with no difference between the ulcer locations (p = 0.694). The local treatment with TLC-NOSF dressing improved the microcirculation in patients with neuroischaemic DFU, regardless of microcirculation status at the baseline, and in the forefoot, regardless of the location.

Exercise Oximetry Correlates Better With Exercise-Induced Lactate Increase, than Ankle Brachial Index or Walking Time, in Vascular Claudicants

In claudication, the correlation between walking-induced biomarkers and indices of clinical severity (e.g., walking distance or ankle brachial index (ABI)), is fair. We hypothesized that a correlation would be observed between the clinical estimation of ischemia severity with exercise transcutaneous oximetry (Ex-TcpO2) and lactate increase. A prospective study was performed among 377 patients with arterial claudication. We recorded age, sex, ABI, body mass index (BMI), systolic arterial blood pressure (SBP), and glycemia. Capillary blood lactate was measured at rest and 3 min after a constant load treadmill test. We recorded maximum walking time (MWT), heart rate (HRmax), the sum of minimal decrease from oxygen values for buttocks, thighs and calves Ex-TcpO2 (DROPmin), as well as the amplitude of chest-TcpO2 decrease. A multilinear regression model was used to assess the variables associated with lactate increase. BMI, SBP, HRmax, the amplitude of decrease in chest-TcpO2 and DROPmin, but not age, sex, ABI, MWT, diabetes mellitus nor glycemia, were significantly associated to lactate increase in the model. Because it accounts for the severity and diffusion of lower-limb exercise-induced ischemia and detects exercise induced hypoxemia, TcpO2 may be preferable to ABI or MWT to estimate the metabolic consequences of walking in claudicants.

Comparison of Three Methods for Preparation of Autologous Cells for Use in Cell Therapy of Chronic Limb-Threatening Ischemia in People with Diabetes

Autologous cell therapy (ACT) is a new therapeutic approach for diabetic patients with no-option chronic limb-threatening ischemia (NO-CLTI). The aim of our study was to quantify cell populations of cell therapy products (CTPs) obtained by three different isolation methods and to correlate their numbers with changes in transcutaneous oxygen pressure (TcPO2). CTPs were separated either from stimulated peripheral blood (PB) (n = 11) or harvested from bone marrow (BM) processed either by Harvest SmartPReP2 (n = 50) or sedimented with succinate gelatin (n = 29). The clinical effect was evaluated by the change in TcPO2 after 1, 3 and 6 months. TcPO2 increased significantly in all three methods at each time point in comparison with baseline values (p < .01) with no significant difference among them. There was no correlation between the change in TcPO2 and the size of injected cell populations. We only observed a weak correlation between the number of injected white blood cells (WBC) and an increase in TcPO2 at 1 and 3 months. Our study showed that all three isolation methods of ACT were similarly relatively efficient in the treatment of NO-CLTI. We observed no correlation of TcPO2 increase with the number of injected monocytes, lymphocytes or CD34+. We observed a weak correlation between TcPO2 increase and the number of injected WBCs.

Skin oxygenation impairment is associated with increased total cholesterol level in children with short-lasting type 1 diabetes mellitus

INTRODUCTION

Transcutaneous oxygen pressure (tcPO2) is a non-invasive method of measuring skin oxygenation that may reflect its superficial perfusion. Skin microvasculature may be impaired in patients with late onset of type 1 diabetes (DM1). However, its condition in children has not been fully determined.

AIM

To compare tcPO2 in children with short-lasting non-complicated DM1 and age-matched healthy controls with regard to concomitant vascular risk factors.

MATERIAL AND METHODS

The study group consisted of 51 paediatric patients aged 14.9 (8.4-18.0) years with short-lasting DM1 without clinical evidence of diabetic micro- or macroangiopathy and 28 control subjects aged 14.8 (11.3-17.7) years. TcPO2 was tested prior, during and after applying post-occlusive reactive hyperaemia (PORH) test in standardized conditions. Biochemical parameters were assessed and then compared between the groups.

RESULTS

TcPO2 at maximal ischemia during PORH was higher in the DM1 patients than in healthy controls (2.4 (0.7-18.8) vs. 1.6 (0.4-12.0), p = 0.002). No differences were found regarding the tcPO2 measurements recorded prior to ischemia or after recovery. In DM1, concentrations of total cholesterol, triglycerides, HbA1c and TSH were significantly higher than in healthy controls. The fT4 levels were significantly lower in the DM1 group. After adjusting for lipid levels, no differences in tcPO2 were found, and a multivariate analysis showed the cholesterol levels have a significant impact on tcPO2 response to maximal ischemia.

CONCLUSIONS

Our results indicate that increased lipid levels are responsible for the impaired skin response to ischemic stimuli in short-lasting DM1. This supports the importance of aggressive lipid control in prevention of early onset microangiopathy in those patients.

High prevalence of exercise-induced ischemia in the asymptomatic limb of patients with apparently strictly unilateral symptoms and unilateral peripheral artery disease

BACKGROUND:

The prevalence of exercise-induced ischemia in the asymptomatic limb of patients with unilateral claudication based on history and treadmill evaluation, and with unilateral ipsilateral peripheral artery disease (i.e ankle-to-brachial systolic pressure index <0.90) is unknown.

METHODS:

We detected exercise-induced ischemia in the asymptomatic limb of patients with apparently unilateral claudication. Among 6059 exercise-oximetry tests performed in 3407 nondiabetic and 961 diabetic patients. We estimated the intensity of ischemia in the both limb (buttocks and calves) using the lowest minimum value of the decrease from rest of oxygen pressure (DROP; limb changes minus chest changes from rest), with significant ischemia defined as DROP lower than -15 mmHg.

RESULTS:

We found 152 tests performed in 142 nondiabetic patients and 40 tests performed in 38 diabetic patients. The asymptomatic limb showed significant ischemia in 46.7% and 37.5% of the tests. Strictly unilateral exercise-induced claudication with apparently unilateral peripheral artery disease was rare (<4% of all tests). However, among these highly selected tests, significant ischemia was found in the asymptomatic limb in more than one-third of cases.

CONCLUSION:

The asymptomatic limb of patients with peripheral artery disease should not be considered a normal limb.

[Application of transcutaneous oxygen pressure in scar assessment]

Objective

To review the application and research progress of transcutaneous oxygen pressure (TcPO ₂) in scar assessment.

Methods

The original articles about scar and TcPO ₂ were reviewed and analyzed.

Results

Hypoxia environment plays an important role in the progression of scar tissue. TcPO ₂ can accurately reflect the oxygen tension of scar tissue, which is of great significance in the assessment of scar maturity, the guidance of scar treatment, and the study of correlations between hypoxia and the progression of scar.

Conclusion

TcPO ₂ measurement is important in the study of scar evaluation, treatment, and correlation between hypoxia and scar formation.

Effect of direct cold atmospheric plasma (diCAP) on microcirculation of intact skin in a controlled mechanical environment

OBJECTIVE

The microcirculatory response of intact human skin to exposure with diCAP for different durations with a focus on the effect of implied mechanical pressure during plasma treatment was investigated.

METHODS

Local relative hemoglobin, blood flow velocity, tissue oxygen saturation, and blood flow were monitored noninvasively for up to 1 hour in 1-2 mm depth by optical techniques, as well as temperature, pH values, and moisture before and after skin stimulation. The experimental protocol (N = 10) was set up to differentiate between pressure- and plasma-induced effects.

RESULTS

Significant increases in microcirculation were only observed after plasma stimulation but not after pressure stimulus alone. For a period of 1 h after stimulation, local relative hemoglobin was increased by 5.1% after 270 seconds diCAP treatment. Tissue oxygen saturation increased by up to 9.4%, whereas blood flow was doubled (+106%). Skin pH decreased by 0.3 after 180 seconds and 270 seconds diCAP treatment, whereas skin temperature and moisture were not affected.

CONCLUSIONS

diCAP treatment of intact skin notably enhances microcirculation for a therapeutically relevant period. This effect is specific to the plasma treatment and not an effect of the applied pressure. Prolonged treatment durations lead to more pronounced effects.

Automated Carbon Dioxide Angiography for the Evaluation and Endovascular Treatment of Diabetic Patients With Critical Limb Ischemia

PURPOSE

To test the safety, efficacy, and diagnostic accuracy of automated carbon dioxide (CO2) angiography (ACDA) for the evaluation of diabetic patients with critical limb ischemia (CLI) and baseline renal insufficiency and compare ACDA with iodinated contrast medium (ICM) during endovascular treatment.

METHODS

From November 2014 to January 2015, 36 consecutive diabetic patients (mean age 74.8±5.8 years; 27 men) with stage ≥3 chronic kidney disease (CKD ≥3) and CLI underwent lower limb angiography with both CO2 and ICM followed by balloon angioplasty in a prospective single-center study. The primary outcome measure was the safety and efficacy of ACDA as the exclusive agent to guide angioplasty in this cohort. The secondary outcomes were the safety and diagnostic accuracy of ACDA injection as compared with ICM digital subtraction angiography (DSA) for invasive evaluation of these patients.

RESULTS

ACDA safely and effectively guided angioplasty in all patients without complications. Transcutaneous oxygen pressure improved from 11.8±6.3 to 58.4±7.6 mm Hg (p<0.001). There were no complications related to ACDA during diagnostic imaging and no significant changes in the estimated glomerular filtration rate from baseline to 24 hours (44.7±13.3 vs 47.0±0.8 mL/min/1.73 m(2); nonsignificant). The diagnostic accuracy of CO2 was 89.8% (sensitivity 92.3%; specificity 75%; positive predictive value 95.5%; negative predictive value 63.1%). There was no statistically significant difference in the qualitative diagnostic accuracy between the media (p=0.197).

CONCLUSION

ACDA is an accurate, safe, and effective technique that can be utilized to guide endovascular interventions in diabetics with CLI and baseline CKD ≥3. Larger multicenter randomized studies are needed to validate these results.

Collective therapy and therapeutic strategy for critical limb ischemia

OBJECTIVE

To determine a treatment strategy based on the outcomes of various previous interventions for critical limb ischemia in arteriosclerosis obliterans (ASO).

MATERIAL AND METHODS

We examined outcomes of 292 ASO patients who had had critical limb ischemia between May 1995 and July 2009. Patients underwent the following procedures in 167 cases: aortofemoral bypass (n = 14), femorofemoral crossover bypass (n = 29), femoropopliteal bypass (n = 104) and femorotibial bypass (n = 40). Other procedures included bypass only (n = 147), bypass combined with thromboendarterectomy (n = 10), bypass combined with endovascular therapy (n = 6), bypass combined with lumbar sympathectomy (n = 2), endovascular therapy combined with thromboendarterectomy (n = 4), endovascular therapy (n = 19), lumbar sympathectomy (n = 6), conservative therapy (n = 65), and major amputation (n = 31). We also calculated P3 risk scores and measured transcutaneous oxygen pressure (tcPO2) and skin perfusion pressure (SPP) before and after therapy.

RESULTS

The limb salvage rate was 87% at 2 years in the arterial reconstruction group. In the low-risk group (a P 3 risk score of 3), the 1-year amputation-free survival rate was 96%. In the medium-risk group (a P 3 risk score of 4-7), the 1-year amputation-free survival rate was 88%. In the high-risk group (a P 3 risk score of 8), the 1-year amputation-free survival rate was 66%. The hospital death rate in the arterial reconstruction group was 3.2%, all of whom were patients who underwent bypass. The survival rate at 5 years was 65% and 36% in the conservative therapy only group. Ulcers healed in 140 out of 144 patients. The 4 patients with unhealed infections had tcPO2 or SPP values of more than 30 mmHg after treatment. Major amputations were performed in 4 of 5 patients who had tcPO2 or SPP values from 20 to 30 mmHg after treatment. Major amputations were performed in all 6 patients who had tcPO2 or SPP values of less than 20 mmHg after treatment.

CONCLUSION

In cases with tcPO2 or SPP values of more than 30 mmHg, an ulcer will probably heal, except in infected cases. We suggest that, if these values are less than 30 mmHg, complete revascularization should be performed. The P3 risk score was useful in predicting limb salvage in the current series. Hybrid therapy in bypass and endovascular therapy must be performed in cases where patients are in a generally poor condition. It is important to attempt amelioration in limb salvage and to control the operative mortality rate with sufficient perioperative control. (English Translation of Jpn J Vasc Surg 2011;20:905-911).

Immersing Feet in Carbon Dioxide-enriched Water Prevents Expansion and Formation of Ischemic Ulcers after Surgical Revascularization in Diabetic Patients with Critical Limb Ischemia

OBJECTIVE

We investigated the effect of immersion of feet in CO2-enriched water for preventing expansion and formation of ischemic ulcer in critical limb ischemia of diabetic patients after surgical revascularization.

MATERIALS AND METHODS

Eligible patients were allocated CO2 group (CO2 immersion plus standard care) or control group (standard care alone) and were followed up for 3 months after surgical revascularization. The end point is defined as an expansion of a target ulcer (more than 101% of original size) or the formation of new ulcers during the follow-up period.

RESULTS

Fifty-nine patients out of originally enrolled 66 patients with type II diabetes were included in intention-to-treat population. The cumulative prevention rate for ischemic ulcer after 3 months was 97.1% in the CO2 group, while, in the control group, it was 77.8%, i.e., significantly lower than the CO2 group (P = 0.012, log-rank test). The transcutaneous oxygen pressure increased significantly only in the CO2 group, from 56 ± 14 to 63 ± 15 mmHg (P < 0.01, Wilcoxon signed rank test), in 3 months.

CONCLUSION

These results suggest that addition of CO2 immersion to standard care of critical limb ischemia in diabetic patients improves early postoperative outcome after vascular surgery.