26 results on '"Sigl M"'
Search Results
2. Long-lasting cold periods in the mid to late-Holocene
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Van Dijk, E., Jungclaus, J., Sigl, M., Timmreck, C., and Krüger, K.
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From paleoproxy reconstructions and climate model simulations of the Northern Hemisphere (NH) climate during the Common Era (CE), we know that strong volcanic eruptions have induced cold periods like the Little Ice Age (LIA) and the mid-6th century cooling. However, less is known about such cold periods during the Holocene. Here, we study the Max Planck Institute Earth System Model Holocene simulations (6000 BCE to 1850 CE). One of the runs is forced with orbital forcing, land cover, greenhouse gas concentrations, solar forcing, stratospheric ozone, and volcanic forcing. The other run includes only orbital forcing and greenhouse gas concentrations. We simulate a large number of extremely cold years in the all-forcing run, which is primarily explained by volcanic eruptions. Applying a 200-year filter reveals 11 long-lasting cold periods similar to the LIA during the mid to late-Holocene, occurring every once or twice per millennium. These long-lasting cold periods correspond to increased volcanic activity, where the clustering of volcanic eruptions leads to an integrated cooling effect through the slow ocean-sea ice response. Eight of the eleven multi-centennial cold periods in our simulation correspond to previously identified phases of glacier advances throughout the NH, as well as reduced ring widths in tree ring records from Northern Finland. Whereas previous studies used mostly local proxy reconstructions, we identify NH annual mean multi-centennial cold periods. Finding several more such cold periods highlights the importance of understanding volcanic-induced long-lasting cold periods and the impact they could have had on society in the past., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)
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- 2023
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3. Volcanic climate forcing preceding the inception of the Younger Dryas: Implications for tracing the Laacher See eruption
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Abbott, P.M., Niemeier, U., Timmreck, C., Riede, F., McConnell, J.R., Severi, M., Fischer, H., Svensson, A., Toohey, M., Reinig, F., and Sigl, M.
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- 2021
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4. The Effect of Revascularization on Lower Limb Circulation Parameters in Symptomatic Peripheral Arterial Disease.
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Gerken ALH, Sigl M, Israel E, Weiß C, Reißfelder C, and Schwenke K
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Background: The prevalence of peripheral arterial disease and the number of revascularization procedures performed in symptomatic patients are steadily increasing. However, uncertainties remain regarding hemodynamic monitoring after revascularization and the prediction of clinical outcomes. This study aimed to investigate hemodynamic parameters with a focus on the microvasculature. Methods: This prospective, single-center study included 29 patients (15 with intermittent claudication [IC] and 14 with chronic limb-threatening ischemia [CLTI]). Before and after the revascularization procedure, in addition to the ankle-brachial index (ABI), microperfusion parameters, including microvascular blood flow, capillary oxygen saturation (SO
2 ), and relative hemoglobin content (rHb), were assessed with lightguide spectrophotometry combined with laser Doppler flowmetry using an oxygen-to-see (O2C) device in the horizontal and elevated leg positions. Results: At baseline, SO2 in the elevated leg position was significantly lower in patients with CLTI than in those with IC ( p = 0.0189), whereas the other microcirculatory parameters and ABI values were not significantly different. Patients with diabetes mellitus had a higher flow rate than those without in the horizontal leg position ( p = 0.0162) but not in the elevated leg position. After successful revascularization, the flow increased immediately and significantly in both positions, whereas SO2 , rHb, and the ABI did not. Conclusions: Elevated leg SO2 was significantly lower in CLTI than in clinically compensated peripheral arterial disease, whereas microvascular flow was a suitable surrogate parameter indicating successful revascularization. In studies using surgical or interventional revascularization procedures, noninvasive hemodynamic monitoring of the microcirculation at the foot level might be beneficial.- Published
- 2024
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5. Prognostic value of extended cardiac risk assessment before elective open abdominal aortic surgery.
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Sigl M, Baumann S, Könemann AS, Keese M, Schwenke K, Gerken ALH, Dürschmied D, and Rosenkaimer S
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- Humans, Male, Risk Assessment, Female, Aged, Prognosis, Germany epidemiology, Survival Rate, Postoperative Complications mortality, Preoperative Care methods, Reproducibility of Results, Treatment Outcome, Vascular Surgical Procedures adverse effects, Comorbidity, Sensitivity and Specificity, Risk Factors, Prevalence, Elective Surgical Procedures mortality, Aorta, Abdominal surgery, Aorta, Abdominal diagnostic imaging
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Background: Major vascular surgery is associated with a high perioperative risk and significant mortality. Despite advances in risk stratification, monitoring, and management of perioperative complications, cardiac complications are still common. Stress echocardiography is well established in coronary artery disease diagnostics; however, its prognostic value before high-risk aortic surgery is unknown. This prospective, single-center study compared the outcome of patients undergoing extended cardiac risk assessment before open abdominal aortic surgery with the outcome of patients who had received standard preoperative assessment., Methods: The study included patients undergoing elective open abdominal aortic surgery. Patients who underwent standard preoperative assessment before the start of a dedicated protocol were compared with patients who had extended cardiac risk assessment, including dobutamine stress echocardiography, as part of a stepwise interdisciplinary cardiovascular team approach. The combined primary endpoint was cardiovascular death, myocardial infarction, emergency coronary revascularization, and life-threatening arrhythmia within 30 days. The secondary endpoint was acute renal failure and severe bleeding., Results: In total, 77 patients (mean age 68.1 ± 8.1 years, 70% male) were included: 39 underwent standard and 38 underwent cardiac risk assessment. The combined primary endpoint was reached significantly more often in patients before than after implementation of the extended cardiac stratification procedure (15% vs. 0%, p = 0.025). The combined secondary endpoint did not differ between the groups., Conclusions: Patients with extended cardiac risk assessment undergoing elective open abdominal aortic surgery had better 30-day outcomes than did those who had standard preoperative assessment., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)
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- 2024
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6. Wellness or medicine? Use and perception of Ayurveda in Germany: data from an online-representative cross-sectional study.
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Schiele JK, Jeitler M, Michalsen A, Stapelfeldt E, Ortiz M, Sigl M, Brinkhaus B, Wischnewsky M, and Kessler CS
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Introduction: Ayurveda, South Asia's largest and most relevant system of Traditional Medicine, holds a legal status akin to conventional Western medicine in India and elsewhere. There is an almost complete lack of data on the use of Ayurveda in Germany. The aim of this study was to investigate Ayurveda's utilization patterns, entry points, and factors influencing its use and the perception of Ayurveda among the German population., Methods: Basis of this manuscript was an online-representative survey which involved 4,065 participants aged 18-75 about the use and acceptance of Traditional, Complementary and Integrative Medicine (TCIM) in Germany. The survey was conducted online using Computer Assisted Web Interview (CAWI) in 2022. The dataset was analyzed descriptively and inferentially., Results: Altogether 9.3% ( n = 377) of all survey participants ( n = 4,065) had already used Ayurveda somehow, either more often (1.7%) or at least once in a lifetime (7.6%). Responders associated Ayurveda primarily with Indian Medicine (27.7%) and wellness (18%). Commonly used Ayurvedic services included non-medical treatments at wellness resorts/spas (48.3%), in outpatient practices (27.1%), and hotels (23.6%). 30.2% of the participants believe in Ayurveda's therapeutic potential. 76.7% of Ayurveda users find healthy nutrition important or very important. Nine predictors were found to classify Ayurveda users vs. non-users with spirituality and belief in Ayurveda's therapeutic efficacy as the most relevant ones. Ayurveda seems to be primarily used by well-educated and female individuals, often from higher-income groups and with a rather modern social milieu-orientation., Conclusion: Study results suggest that about every tenth German citizen has used Ayurveda in the past and about one third believes in its therapeutic potential. Because Ayurvedic therapies are often not evidence-based, there is an urgent need to perform high quality randomized controlled trials to investigate potential effects and safety of Ayurveda and how evidence-based Ayurveda treatments can be integrated into the German healthcare system., Competing Interests: JS works self-employed as a nutritionist and alternative practitioner specializing in Ayurveda. She is also a lecturer at the “Sonne und Mond” Health Center in Berlin, training in Ayurvedic medicine. MJ received grants from the Karl and Veronica Carstens Foundation. CK is a lecturer at the “Sonne und Mond” Health Center, Berlin. He is on the scientific advisory board of the Bruno Zimmer company and a board member of the German Medical Association for Ayurveda (DÄGAM e.V.). BB and his working group were partly funded by the Kneipp-Bund e.V., by the Software AG foundation, by the BKK 24 health insurance company, by the Kneipp town Bad Wörishofen, by the Immanuel Albertinen Diakonie gGmbH and the Karl and Veronica Carstens Foundation. MO is a board member of the Berlin Brandenburg Medical Doctors’ Association for Naturheilkunde (Physiotherapy) (ÄN e.V.). ES works as a nutritionist and alternative practitioner specializing in Ayurveda. He is also a lecturer at the “Sonne und Mond” Health Center in Berlin, training in Ayurvedic medicine. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Schiele, Jeitler, Michalsen, Stapelfeldt, Ortiz, Sigl, Brinkhaus, Wischnewsky and Kessler.)
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- 2024
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7. Peripheral Arterial Disease and the Diabetic Foot Syndrome: Neuropathy Makes the Difference! A Narrative Review.
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Rümenapf G, Abilmona N, Morbach S, and Sigl M
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Background : In vascular medicine, peripheral arterial disease (PAD) and diabetic foot syndrome (DFS) are often considered synonymous with respect to the need for revascularization. In PAD patients, clinical symptoms reflect the degree of atherosclerotic disease, since peripheral innervation, including pain sensation, is not usually compromised. In DFS patients, however, symptoms of relevant foot ischemia are often absent and progression of ischemia goes unnoticed owing to diabetic polyneuropathy, the loss of nociception being the main trigger for foot ulcers. This review analyzes the fundamental differences between PAD and DFS against the background of polyneuropathy. Methods : The literature research for the 2014 revision of the German evidence-based S3-PAD-guidelines was extended to 2023. Results : Vascular examination is imperative for both, PAD and DFS. Stage-dependent revascularization is of utmost importance in PAD patients, especially those suffering from critical limb-threatening ischemia (CLTI). Successful therapy of DFS goes further, including infection and metabolic control, wound management, offloading the foot and lifelong prophylaxis in the course of a multidisciplinary treatment concept. Revascularization is not needed in all cases of DFS. Conclusions : There are fundamental differences between PAD and DFS with respect to pathophysiology, the anatomical distribution of arterial occlusive processes, the clinical symptoms, the value of diagnostic tools such as the ankle-brachial index, and classification. Also, therapeutic concepts differ substantially between the two patient populations.
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- 2024
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8. Use and acceptance of traditional, complementary and integrative medicine in Germany-an online representative cross-sectional study.
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Jeitler M, Ortiz M, Brinkhaus B, Sigl M, Hoffmann R, Trübner M, Michalsen A, Wischnewsky M, and Kessler CS
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Background: Older representative surveys show that Traditional, Complementary and Integrative Medicine (TCIM) is used by about 60% of the German population. However, no data exists for the current nationwide situation. The main aim of this cross-sectional study is to investigate the current use and acceptance of TCIM in Germany., Methods: This study is based on a representative sample of the German population aged 18-75 years. Participants were asked about the use and acceptance of TCIM. The survey was conducted online using Computer Assisted Web Interview (CAWI) in 2022 by three renowned German market research institutes on behalf of and in close coordination with the working group. The data set was analyzed descriptively and inferentially., Results: In total, 4,065 participants (52% female, 48% male, 0.4% diverse) responded completely (response rate: 21.5%). Among participants, 70% stated that they had used TCIM at some point in their lives, with 32% doing so in the last 12 months and 18% currently. The most common reason given (17%) was musculoskeletal pain. For their own health, 39% stated that TCIM is important. Traditional European Medicine was rated as very/mainly effective by 27% of participants and as partly effective by 44% (conventional medicine: 69% very/mainly effective, 19% partly effective). As a complementary treatment strategy to conventional medicine, 35% considered TCIM to be optimal ("Complementary Medicine"), 33% in combination with conventional medicine ("Integrative Medicine") and 5% without conventional medicine ("Alternative Medicine"). The majority of the participants were in favor of more research on TCIM and stated that the costs of TCIM services should be covered by health insurance companies (71% and 69%, respectively)., Conclusion: These results from a representative online-population suggest that the use of TCIM in Germany remains at a high level. The nationwide relevance of TCIM should be given greater consideration in German health care policy making. TCIM should be systematically investigated using appropriate study designs and methods including high quality randomized clinical trials to investigate their effectiveness, efficacy, therapeutic safety and costs in the future., Competing Interests: MJ reports grants from the Karl and Veronica Carstens Foundation. MO is a board member of the Berlin Brandenburg Medical Doctors’ Association for Naturheilkunde (Physiotherapy; ÄN e.V.). AM reports grants from the Karl and Veronica Carstens Foundation and Stifterverband der Deutschen Wissenschaft. He receives honoraria for consulting from the Klosterfrau Foundation. BB and its working group were partly funded by the Kneipp-Bund e.V. MT reports grants from the Karl and Veronica Carstens Foundation. CK reports grants from the Karl and Veronica Carstens Foundation for conducting this study. He is a member of the scientific advisory board of the company Bruno Zimmer, board member of the German Medical Doctors’ Association for Ayurveda-Medicine (DÄGAM e.V.) and receives honoraria for lecturing Ayurveda at Sonne und Mond, Berlin. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Jeitler, Ortiz, Brinkhaus, Sigl, Hoffmann, Trübner, Michalsen, Wischnewsky and Kessler.)
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- 2024
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9. Can acupuncture increase microcirculation in peripheral artery disease and diabetic foot syndrome? - a pilot study.
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Valentini J, Sigl M, Dunckel C, Krisam J, Amendt K, and Greten HJ
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Background: Globally, diabetes mellitus (DM) and peripheral artery disease (PAD) have an increasing incidence and a high prevalence and are both associated with high morbidity and complication rates, e.g., as chronic non-healing peripheral ulcers. Impaired macro- and microcirculation and peripheral neuropathy lead to an increased risk of foot ulcers and infections. These complications are difficult to treat, have a high risk of becoming chronic and often lead to lower limb amputation. The aim of this planned study was to investigate the potential effects of acupuncture on improving microcirculation in patients with Diabetic Foot Syndrome (DFS) and PAD., Materials and Methods: In 18 patients with chronic non-healing peripheral ulcers and diagnosed DM or PAD, data on 8 microcirculatory parameters were collected simultaneously on intact skin close to the wound margin. Microcirculation was assessed using an O2C device combining laser Doppler shift and white light spectroscopy (LEA Medizintechnik GmbH, Giessen, Germany). Unilateral and bilateral acupuncture was performed on the connecting line between acupuncture points Stomach 14 and Stomach 15., Results: After unilateral acupuncture (ipsilateral to the wound side), a statistically significant improvement in 7 out of 8 microcirculatory parameters was demonstrated compared to baseline measurements before acupuncture. After bilateral acupuncture, there was an additional improvement and statistical significance in all parameters in both DFS and PAD patients., Discussion: These results show an improvement in the microcirculation and peripheral blood flow at the edges of the wound. As impaired micro- and macrocirculation is considered to be a critical prognostic factor for the healing of a peripheral lesion, the intervention could have a positive impact on the healing of (chronic) peripheral wounds., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Valentini, Sigl, Dunckel, Krisam, Amendt and Greten.)
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- 2024
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10. Phasing and climate forcing potential of the Millennium Eruption of Mt. Baekdu.
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Lee G, Burke A, Hutchison W, Sugden P, Smith C, McConnell JR, Sigl M, Oppenheimer C, Rasmussen SO, Steffensen JP, Lee SR, and Ahn J
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The Millennium Eruption of Mt. Baekdu, one of the largest volcanic eruptions in the Common Era, initiated in late 946. It remains uncertain whether its two main compositional phases, rhyolite and trachyte, were expelled in a single eruption or in two. Investigations based on proximal and medial ash have not resolved this question, prompting us to turn to high-resolution ice-core evidence. Here, we report a suite of glaciochemical and tephra analyses of a Greenlandic ice core, identifying the transition from rhyolitic to trachytic tephra with corresponding spikes in insoluble particle fallout. By modeling annual snow accumulation, we estimate an interval of one to two months between these spikes, which approximates the hiatus between two eruptive phases. Additionally, negligible sulfur mass-independent fractionation, near-synchroneity between particle and sulfate deposition, and peak sulfur fallout in winter all indicate an ephemeral aerosol veil. These factors limited the climate forcing potential of the Millennium Eruption., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2024.)
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- 2024
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11. Adipose-Derived Mesenchymal Stem Cells Protect Endothelial Cells from Hypoxic Injury by Suppressing Terminal UPR In Vivo and In Vitro.
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Keese M, Zheng J, Yan K, Bieback K, Yard BA, Pallavi P, Reissfelder C, Kluth MA, Sigl M, and Yugublu V
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- Humans, Animals, Mice, Neovascularization, Physiologic physiology, Adipose Tissue metabolism, Hypoxia metabolism, Unfolded Protein Response, Ischemia metabolism, Apolipoproteins E genetics, Apolipoproteins E metabolism, Endothelial Cells metabolism, Mesenchymal Stem Cells metabolism
- Abstract
Adipose-derived stem cells (ASCs) have been used as a therapeutic intervention for peripheral artery disease (PAD) in clinical trials. To further explore the therapeutic mechanism of these mesenchymal multipotent stromal/stem cells in PAD, this study was designed to test the effect of xenogeneic ASCs extracted from human adipose tissue on hypoxic endothelial cells (ECs) and terminal unfolded protein response (UPR) in vitro and in an atherosclerosis-prone apolipoprotein E-deficient mice (ApoE
-/- mice) hindlimb ischemia model in vivo. ASCs were added to Cobalt (II) chloride-treated ECs; then, metabolic activity, cell migration, and tube formation were evaluated. Fluorescence-based sensors were used to assess dynamic changes in Ca2+ levels in the cytosolic- and endoplasmic reticulum (ER) as well as changes in reactive oxygen species. Western blotting was used to observe the UPR pathway. To simulate an acute-on-chronic model of PAD, ApoE-/- mice were subjected to a double ligation of the femoral artery (DLFA). An assessment of functional recovery after DFLA was conducted, as well as histology of gastrocnemius. Hypoxia caused ER stress in ECs, but ASCs reduced it, thereby promoting cell survival. Treatment with ASCs ameliorated the effects of ischemia on muscle tissue in the ApoE-/- mice hindlimb ischemia model. Animals showed less muscle necrosis, less inflammation, and lower levels of muscle enzymes after ASC injection. In vitro and in vivo results revealed that all ER stress sensors (BIP, ATF6, CHOP, and XBP1) were activated. We also observed that the expression of these proteins was reduced in the ASCs treatment group. ASCs effectively alleviated endothelial dysfunction under hypoxic conditions by strengthening ATF6 and initiating a transcriptional program to restore ER homeostasis. In general, our data suggest that ASCs may be a meaningful treatment option for patients with PAD who do not have traditional revascularization options.- Published
- 2023
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12. The impact of class I compression stockings on the peripheral microperfusion of the lower limb: A prospective pilot study.
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Gerken ALH, Hattemer MA, Weiß C, Sigl M, Zach S, Keese M, Nowak K, Reißfelder C, Rahbari NN, and Schwenke K
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- Humans, Pilot Projects, Prospective Studies, Cohort Studies, Lower Extremity, Edema therapy, Stockings, Compression, Peripheral Arterial Disease therapy
- Abstract
Objective: The use of medical compression stockings (MCS) in patients with peripheral arterial disease (PAD) and diabetes is the subject of an ongoing critical debate. While reducing leg edema of various origins by improving venous back flow, there is a concern about additional arterial flow obstruction when compression therapy is applied in pre-existing PAD. The aim of this study is to obtain further information on the use of class I MCS in patients with advanced PAD and to evaluate the framework conditions for a safe application., Methods: The total collective (n = 55) of this prospective, clinical cohort study consisted of 24 patients with PAD Fontaine stage IIb and higher studied before revascularization, of whom 16 patients were examined again after revascularization, and 15 healthy participants included for reference. The microperfusion of the lower extremity of all participants was examined in a supine, elevated, and sitting position using the oxygen to see (O2C) method., Results: The results indicate that leg positioning had the strongest influence on microcirculation (SO2 and flow: p = 0.0001), whereas MCS had no significant effect on the perfusion parameters (SO2: p = 0.9936; flow: p = 0.4967) and did not lead to a deterioration of values into critical ranges., Conclusion: Mild medical compression therapy appears to be feasible even in patients with advanced PAD. Larger studies are warranted to observe any long-term effects, in particular for the treatment of reperfusion edema after revascularization., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023. Published by Elsevier Inc.)
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- 2023
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13. A Systematic Review and Bayesian Network Meta-Analysis on the Effect of Different Anticoagulants on the Prophylaxis of Post-Thrombotic Syndrome after Deep Venous Thrombosis.
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Shao J, Zhou Q, Jin F, Reissfelder C, Sigl M, Yagublu V, and Keese M
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Background: Postthrombotic syndrome (PTS) has a major impact on the quality of life after deep venous thrombosis (DVT). From clinical practice and related trials, anticoagulants show potential for reducing the occurrence and alleviating the symptoms of PTS., Methods: A systematic review and Bayesian network meta-analysis (NMA) were conducted by combing the literature from the databases of MEDLINE, Embase, Web of Science, Cochrane Libraries, and ClinicalTrials, through a variety of medical subject headings (Mesh) and PTS keywords. With regard to PTS prophylaxis, all anticoagulant-related randomized controlled trials (RCTs) and observational studies were assessed. The network model was conducted through the R software, and further comparisons were conducted using the Bayesian hierarchical random effects model. The odds ratio (OR) and the corresponding 95% CI were calculated for analysis., Results: Data from two RCTs and nine non-randomized studies meeting the selection criteria were included in the Bayesian analysis model, which incorporated seven anticoagulants. Edoxaban (OR: 0.42, 95% CI: 0.18-1.0) and rivaroxaban (OR: 0.54, 95% CI: 0.38-0.76) were significantly more effective than warfarin in the prevention of PTS (Villalta score ≥ 5). A subgroup analysis based on the severity of PTS showed that rivaroxaban was more effective than warfarin, with OR: 0.59, 95% CI: 0.41-0.84 (Villalta score 5 to 14) and OR: 0.48, 95% CI: 0.22-0.9 (Villalta score ≥ 15, ulceration), respectively. Edoxaban had the highest probability (80.1%) of providing preventive benefits for PTS. For mild/moderate and severe PTS, rivaroxaban provided the highest benefits in preventing PTS (89.3% and 85.6%, respectively)., Conclusion: Edoxaban demonstrated a better prophylactic effect on PTS (Villalta score > 5), while rivaroxaban displayed a better effect against mild/moderate (Villalta score 5 to 14) and severe PTS (Villalta score ≥ 15, ulceration).
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- 2023
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14. First experiences of ultrasound vector flow imaging at the femoropopliteal artery in peripheral arterial disease.
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Shchetynska-Marinova T, Gerdes L, Hohneck AL, Winter L, Amendt K, Schwenke K, Gerken ALH, Du Y, Dürschmied D, and Sigl M
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- Humans, Prospective Studies, Ultrasonography methods, Carotid Artery, Common diagnostic imaging, Blood Flow Velocity, Femoral Artery diagnostic imaging, Peripheral Arterial Disease diagnostic imaging, Peripheral Arterial Disease therapy
- Abstract
Background: The femoropopliteal artery (FPA) plays a central role in diagnosing and treating peripheral arterial disease (PAD). FPA lesions are the most frequent cause of intermittent claudication, and no other artery of the lower extremities is recanalised more frequently. Generally, ultrasound is the primary imaging tool in PAD, particularly FPA. With the development of high-frame-rate ultrasound technology in addition to traditional ultrasound modes, vector flow imaging (VFI) has provided deeper haemodynamic insights when used in the carotid artery. Here, we report the use of VFI at the FPA level in routine PAD examinations. Patients and methods: In this single-centre prospective study, we evaluated consecutive patients with PAD using B-mode imaging, colour Doppler, pulsed wave Doppler (PW) and vector flow. Hemodynamic parameters at predefined locations at the carotid artery and FPA were compared. Results: Qualitatively adequate VFI at all sites was possible in 76% of the patients with PAD. With decreasing volume flow from the common carotid artery to the internal carotid artery and from the common femoral artery via the superficial femoral artery to the popliteal artery, the correlation between VFI- and PW-derived-volume flow was high at every site. Based on different techniques, the VFI-derived values were significantly lower than the PW-derived values. The mean wall shear stress was significantly lower at all femoropopliteal sites than at the carotid sites, whereas the oscillatory shear index at the femoral site was higher than that at the carotid sites rather than at the popliteal location. Conclusions: Our findings suggest that vector flow data acquisition in the FPA is feasible in most patients with PAD. Therefore, with knowledge of the method and its limitations, VFI provides haemodynamic information beyond traditional ultrasound techniques and is a promising new tool for flow analysis in PAD.
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- 2023
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15. Volcanic glass from the 1.8 ka Taupō eruption (New Zealand) detected in Antarctic ice at ~ 230 CE.
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Piva SB, Barker SJ, Iverson NA, Winton VHL, Bertler NAN, Sigl M, Wilson CJN, Dunbar NW, Kurbatov AV, Carter L, Charlier BLA, and Newnham RM
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Chemical anomalies in polar ice core records are frequently linked to volcanism; however, without the presence of (crypto)tephra particles, links to specific eruptions remain speculative. Correlating tephras yields estimates of eruption timing and potential source volcano, offers refinement of ice core chronologies, and provides insights into volcanic impacts. Here, we report on sparse rhyolitic glass shards detected in the Roosevelt Island Climate Evolution (RICE) ice core (West Antarctica), attributed to the 1.8 ka Taupō eruption (New Zealand)-one of the largest and most energetic Holocene eruptions globally. Six shards of a distinctive geochemical composition, identical within analytical uncertainties to proximal Taupō glass, are accompanied by a single shard indistinguishable from glass of the ~25.5 ka Ōruanui supereruption, also from Taupō volcano. This double fingerprint uniquely identifies the source volcano and helps link the shards to the climactic phase of the Taupō eruption. The englacial Taupō-derived glass shards coincide with a particle spike and conductivity anomaly at 278.84 m core depth, along with trachytic glass from a local Antarctic eruption of Mt. Melbourne. The assessed age of the sampled ice is 230 ± 19 CE (95% confidence), confirming that the published radiocarbon wiggle-match date of 232 ± 10 CE (2 SD) for the Taupō eruption is robust., (© 2023. Springer Nature Limited.)
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- 2023
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16. Solution-Processable Cu 3 BiS 3 Thin Films: Growth Process Insights and Increased Charge Generation Properties by Interface Modification.
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Rath T, Marin-Beloqui JM, Bai X, Knall AC, Sigl M, Warchomicka FG, Griesser T, Amenitsch H, and Haque SA
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Cu
3 BiS3 thin films are fabricated via spin coating of precursor solutions containing copper and bismuth xanthates onto planar glass substrates or mesoporous metal oxide scaffolds followed by annealing at 300 °C to convert the metal xanthates into copper bismuth sulfide. Detailed insights into the film formation are gained from time-resolved simultaneous small and wide angle X-ray scattering measurements. The Cu3 BiS3 films show a high absorption coefficient and a band gap of 1.55 eV, which makes them attractive for application in photovoltaic devices. Transient absorption spectroscopic measurements reveal that charge generation yields in mesoporous TiO2 /Cu3 BiS3 heterojunctions can be significantly improved by the introduction of an In2 S3 interlayer, and long-lived charge carriers ( t50% of 10 μs) are found.- Published
- 2023
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17. Comparison of Functional and Morphological Estimates of Vascular Age.
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Sigl M, Winter L, Schumacher G, Helmke SC, Shchetynska-Marinova T, Amendt K, Duerschmied D, and Hohneck AL
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- Humans, Female, Adult, Middle Aged, Male, Risk Factors, Carotid Intima-Media Thickness, Carotid Arteries, Ultrasonography, Pulse Wave Analysis, Plaque, Atherosclerotic, Vascular Stiffness
- Abstract
Background/aim: Vascular age (VA) is an emerging metric in preventive cardiovascular (CV) medicine. VA can be derived from morphological parameters such as carotid intima-media thickness (CIMT), or functional parameters such as pulse wave analysis (PWA), which celebrates its 100
th birthday. This study aimed to investigate whether the results of both approaches are comparable., Patients and Methods: On the occasion of the double 100th anniversary of PWA and the Mannheim Clinic, 100 volunteers underwent a) bilateral CIMT assessment using high-resolution ultrasound and b) oscillometric PWA at the brachial forearm site. The respective VAs were calculated using previously published equations., Results: Median age of the participants was 53.6 years (range=39.8-62.6 years), and 56% were female. Median CIMT was 632.5 μm (range=548.8-730.0 μm). Median PWA-derived VA was 55.3 years (36.5-70.5 years). Different values were obtained for CIMT-derived VA, depending on the reference cohort used as calculation basis, ranging from median 43.7 (26.2-59.5 years) to median 64.0 years (43.5-82.1 years). In 46% of the participants divergent VAs were found, that is, the calculated age was higher according to one method and lower according to the other. Correlation analysis revealed a strong dependence of VA (both PWA- and CIMT-derived) and chronological age, as well as an increase in CV risk factors and the detection of plaques with age., Conclusion: Different approaches for estimating VA are not comparable and often produce contradictory results. The current methods and their validity must be critically assessed if they are not standardized., (Copyright © 2023, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)- Published
- 2023
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18. Reply to: Possible magmatic CO 2 influence on the Laacher See eruption date.
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Reinig F, Wacker L, Jöris O, Oppenheimer C, Guidobaldi G, Nievergelt D, Adolphi F, Cherubini P, Engels S, Esper J, Keppler F, Land A, Lane C, Pfanz H, Remmele S, Sigl M, Sookdeo A, and Büntgen U
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- 2023
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19. Lunar eclipses illuminate timing and climate impact of medieval volcanism.
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Guillet S, Corona C, Oppenheimer C, Lavigne F, Khodri M, Ludlow F, Sigl M, Toohey M, Atkins PS, Yang Z, Muranaka T, Horikawa N, and Stoffel M
- Abstract
Explosive volcanism is a key contributor to climate variability on interannual to centennial timescales
1 . Understanding the far-field societal impacts of eruption-forced climatic changes requires firm event chronologies and reliable estimates of both the burden and altitude (that is, tropospheric versus stratospheric) of volcanic sulfate aerosol2,3 . However, despite progress in ice-core dating, uncertainties remain in these key factors4 . This particularly hinders investigation of the role of large, temporally clustered eruptions during the High Medieval Period (HMP, 1100-1300 CE), which have been implicated in the transition from the warm Medieval Climate Anomaly to the Little Ice Age5 . Here we shed new light on explosive volcanism during the HMP, drawing on analysis of contemporary reports of total lunar eclipses, from which we derive a time series of stratospheric turbidity. By combining this new record with aerosol model simulations and tree-ring-based climate proxies, we refine the estimated dates of five notable eruptions and associate each with stratospheric aerosol veils. Five further eruptions, including one responsible for high sulfur deposition over Greenland circa 1182 CE, affected only the troposphere and had muted climatic consequences. Our findings offer support for further investigation of the decadal-scale to centennial-scale climate response to volcanic eruptions., (© 2023. The Author(s).)- Published
- 2023
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20. Revised historical Northern Hemisphere black carbon emissions based on inverse modeling of ice core records.
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Eckhardt S, Pisso I, Evangeliou N, Zwaaftink CG, Plach A, McConnell JR, Sigl M, Ruppel M, Zdanowicz C, Lim S, Chellman N, Opel T, Meyer H, Steffensen JP, Schwikowski M, and Stohl A
- Subjects
- Atmosphere, Soot analysis, Carbon, Fossil Fuels, Climate
- Abstract
Black carbon emitted by incomplete combustion of fossil fuels and biomass has a net warming effect in the atmosphere and reduces the albedo when deposited on ice and snow; accurate knowledge of past emissions is essential to quantify and model associated global climate forcing. Although bottom-up inventories provide historical Black Carbon emission estimates that are widely used in Earth System Models, they are poorly constrained by observations prior to the late 20th century. Here we use an objective inversion technique based on detailed atmospheric transport and deposition modeling to reconstruct 1850 to 2000 emissions from thirteen Northern Hemisphere ice-core records. We find substantial discrepancies between reconstructed Black Carbon emissions and existing bottom-up inventories which do not fully capture the complex spatial-temporal emission patterns. Our findings imply changes to existing historical Black Carbon radiative forcing estimates are necessary, with potential implications for observation-constrained climate sensitivity., (© 2023. The Author(s).)
- Published
- 2023
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21. Seasonal temperatures in West Antarctica during the Holocene.
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Jones TR, Cuffey KM, Roberts WHG, Markle BR, Steig EJ, Stevens CM, Valdes PJ, Fudge TJ, Sigl M, Hughes AG, Morris V, Vaughn BH, Garland J, Vinther BM, Rozmiarek KS, Brashear CA, and White JWC
- Abstract
The recovery of long-term climate proxy records with seasonal resolution is rare because of natural smoothing processes, discontinuities and limitations in measurement resolution. Yet insolation forcing, a primary driver of multimillennial-scale climate change, acts through seasonal variations with direct impacts on seasonal climate
1 . Whether the sensitivity of seasonal climate to insolation matches theoretical predictions has not been assessed over long timescales. Here, we analyse a continuous record of water-isotope ratios from the West Antarctic Ice Sheet Divide ice core to reveal summer and winter temperature changes through the last 11,000 years. Summer temperatures in West Antarctica increased through the early-to-mid-Holocene, reached a peak 4,100 years ago and then decreased to the present. Climate model simulations show that these variations primarily reflect changes in maximum summer insolation, confirming the general connection between seasonal insolation and warming and demonstrating the importance of insolation intensity rather than seasonally integrated insolation or season duration2,3 . Winter temperatures varied less overall, consistent with predictions from insolation forcing, but also fluctuated in the early Holocene, probably owing to changes in meridional heat transport. The magnitudes of summer and winter temperature changes constrain the lowering of the West Antarctic Ice Sheet surface since the early Holocene to less than 162 m and probably less than 58 m, consistent with geological constraints elsewhere in West Antarctica4-7 ., (© 2023. The Author(s).)- Published
- 2023
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22. Concurrent stimulation of monocytes with CSF1 and polarizing cytokines reveals phenotypic and functional differences with classical polarized macrophages.
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An L, Michaeli J, Pallavi P, Breedijk A, Xu X, Dietrich N, Sigl M, Keese M, Nitschke K, Jarczyk J, Nuhn P, Krämer BK, Yard BA, and Leipe J
- Subjects
- Cell Differentiation, Cells, Cultured, Cyclooxygenase 2 metabolism, Lipopolysaccharides metabolism, Lipopolysaccharides pharmacology, Macrophages metabolism, Cytokines metabolism, Monocytes metabolism
- Abstract
In atherosclerotic lesions, macrophages are exposed to CSFs and various microenvironmental cues, which ultimately drive their polarization state. We studied the expression of different CSFs in artery specimen and cultured vascular cells and assessed whether concurrent stimulation (CS) of monocytes with CSF1 and polarizing cytokines generated macrophages (CSM1 and CSM2) that were phenotypically and functionally different from classically polarized M1 and M2 macrophages. We also assessed the influence of acetylsalicylic acid (ASA) on the capacity of polarized macrophages to stimulate T-cell proliferation. CSF1 was the most prominent CSF expressed in arteries and cultured vascular cells. M1 and CSM1 macrophages differed in CD86 and CD14 expression, which was up-regulated respectively down-regulated by LPS. M2 and CSM2 macrophages were phenotypically similar. Cyclooxygenase expression was different in CSM1 (COX-1
- and COX-2+ after LPS stimulation) and CSM2 (COX-1+ and COX-2- ) macrophages. TNFα production was more pronounced in CSM1 macrophages, whereas IL-10 was produced at higher levels by CSM2 macrophages. Proliferation of allogeneic T cells was strongly supported by CSM2, but not by CSM1 polarized macrophages. Although ASA did not affect anti-CD3/CD28-mediated proliferation, it significantly reduced CSM2 and CSM1-mediated T-cell proliferation. Supernatants of LPS-stimulated CSM2 but not of CSM1 macrophages could overcome the inhibition by ASA. Hence, we demonstrate that CSM1 and CSM2 macrophages are phenotypically and to some extent functionally distinct from classically polarized M1 and M2 macrophages. CSM2 macrophages produce a COX-1-dependent soluble factor that supports T-cell proliferation, the identity hereof is still elusive and warrants further studies., (© 2022 The Authors. Journal of Leukocyte Biology published by Wiley Periodicals LLC on behalf of Society for Leukocyte Biology.)- Published
- 2022
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23. Polyvascular disease, pulse pressure and mortality.
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Yazdani B, Kleber ME, Yücel G, Delgado GE, Husain-Syed F, Krüger B, März W, Schwenke K, Sigl M, and Krämer BK
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- Blood Pressure, Cohort Studies, Coronary Angiography, Humans, Risk Factors, Carotid Stenosis complications, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease epidemiology, Peripheral Arterial Disease complications, Peripheral Arterial Disease diagnostic imaging
- Abstract
Background: Peripheral arterial disease (PAD), coronary artery disease (CAD) and carotid stenosis (CS) are robust predictors of mortality. The value of individual vascular beds in polyvascular disease (PVD) to predict mortality in patients with atherosclerotic burden is not clear. Therefore, we have examined the predictive value of PAD, CAD and CS in patients at intermediate to high risk of cardiovascular (CV) disease. Patients and methods: In our retrospective observational study we analyzed baseline data from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study, a monocentric cohort study of 3316 patients referred to coronary angiography. Results: As the number of atherosclerotic vascular beds increased, the hazard ratios (HRs) for both all-cause mortality and CV mortality significantly increased in a multivariate analysis after adjusting for age, sex, body mass index, diabetes mellitus and estimated glomerular filtration rate, with HRs of 1.36 (95%CI: 1.11-1.68), 2.56 (95%CI: 2.01-3.26), 2.84 (95%CI: 1.93-4.17) and 1.56 (95%CI: 1.19-2.06), 2.70 (95%CI: 1.97-3.72), 3.50 (95%CI: 2.19-5.62), respectively. The combination of PAD with either CAD or CS was associated with higher HRs for all-cause (HR 2.81 and 7.53, respectively) and CV (HRs 2.80 and 6.03, respectively) mortality compared with the combination of CAD and CS (HRs 1.94 and 2.43, respectively). The presence of PVD was associated with higher age, systolic blood pressure, pulse pressure (PP; a marker of vascular stiffness), former smoking and inversely with lower eGFR. Conclusions: We show that as the number of atherosclerotic vascular beds increases, all-cause and CV mortality rates increase in parallel. Simultaneous prevalence of PAD is associated with significantly higher all-cause and CV mortality rates compared with CS coexistence. Furthermore, increasing atherosclerotic load may contribute to vascular stiffness and impaired renal function.
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- 2022
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24. Geochemical ice-core constraints on the timing and climatic impact of Aniakchak II (1628 BCE) and Thera (Minoan) volcanic eruptions.
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Pearson C, Sigl M, Burke A, Davies S, Kurbatov A, Severi M, Cole-Dai J, Innes H, Albert PG, and Helmick M
- Abstract
Decades of research have focused on establishing the exact year and climatic impact of the Minoan eruption of Thera, Greece (c.1680 to 1500 BCE). Ice cores offer key evidence to resolve this controversy, but attempts have been hampered by a lack of multivolcanic event synchronization between records. In this study, Antarctic and Greenland ice-core records are synchronized using a double bipolar sulfate marker, and calendar dates are assigned to each eruption revealed within the 'Thera period'. From this global-scale sequence of volcanic sulfate loading, we derive indications toward each eruption's latitude and potential to disrupt the climate system. Ultrafine sampling for sulfur isotopes and tephra conclusively demonstrate a colossal eruption of Alaska's Aniakchak II as the source of stratospheric sulfate in the now precisely dated 1628 BCE ice layer. These findings end decades of speculation that Thera was responsible for the 1628 BCE event, and place Aniakchak II (52 ± 17 Tg S) and an unknown volcano at 1654 BCE (50 ± 13 Tg S) as two of the largest Northern Hemisphere sulfur injections in the last 4,000 years. This opens possibilities to explore widespread climatic impacts for contemporary societies and, in pinpointing Aniakchak II, confirms that stratospheric sulfate can be globally distributed from eruptions outside the tropics. Dating options for Thera are reduced to a series of precisely dated, constrained stratospheric sulfur injection events at 1611 BCE, 1561/1558/1555BCE, and c.1538 BCE, which are all below 14 ± 5 Tg S, indicating a climatic forcing potential for Thera well below that of Tambora (1815 CE)., (© The Author(s) 2022. Published by Oxford University Press on behalf of the National Academy of Sciences.)
- Published
- 2022
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25. Therapeutic Alternatives in Diabetic Foot Patients without an Option for Revascularization: A Narrative Review.
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Ruemenapf G, Morbach S, and Sigl M
- Abstract
Background: The healing of foot wounds in patients with diabetes mellitus is frequently complicated by critical limb threatening ischemia (neuro-ischemic diabetic foot syndrome, DFS). In this situation, imminent arterial revascularization is imperative in order to avoid amputation. However, in many patients this is no longer possible ("too late", "too sick", "no technical option"). Besides conservative treatment or major amputation, many alternative methods supposed to decrease pain, promote wound healing, and avoid amputations are employed. We performed a narrative review in order to stress their efficiency and evidence., Methods: The literature research for the 2014 revision of the German evidenced-based S3-PAD-guidelines was extended to 2020., Results: If revascularization is impossible, there is not enough evidence for gene- and stem-cell therapy, hyperbaric oxygen, sympathectomy, spinal cord stimulation, prostanoids etc. to be able to recommend them. Risk factor management is recommended for all CLTI patients. With appropriate wound care and strict offloading, conservative treatment may be an effective alternative. Timely amputation can accelerate mobilization and improve the quality of life., Conclusions: Alternative treatments said to decrease the amputation rate by improving arterial perfusion and wound healing in case revascularization is impossible and lack both efficiency and evidence. Conservative therapy can yield acceptable results, but early amputation may be a beneficial alternative. Patients unfit for revascularization or major amputation should receive palliative wound care and pain therapy. New treatment strategies for no-option CLTI are urgently needed.
- Published
- 2022
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26. First experiences of local pulse wave velocity measurements in 4D-MRI in focally stented femoropopliteal arteries.
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Hermann I, Shchetynska-Marinova T, Amendt K, Hohneck AL, Schönberg SO, Zöllner FG, and Sigl M
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- Adult, Aged, Blood Flow Velocity, Femoral Artery diagnostic imaging, Humans, Magnetic Resonance Imaging, Stents, Pulse Wave Analysis, Vascular Stiffness
- Abstract
Background: In peripheral arterial disease (PAD) the femoropopliteal (FP) artery is the most frequently recanalized lower limb artery. Stent-based interventions change the biomechanical properties of FP arteries. However, no clinical tool for functional imaging is established for quantitative measurements in vivo. Four-dimensional-flow magnetic resonance imaging enables a detailed evaluation of the hemodynamics of the central and - more challenging - the peripheral arteries. The present study aimed to determine the feasibility of assessing pulse wave velocities (PWV) as a marker of vessel stiffness in PAD patients with multiple spot stents and to compare the values with age-matched subjects and young-adult healthy subjects. Patients and methods: Four-D-flow MRI sequences offering high spatial and temporal resolution enables quantification of flow velocity measurements and estimation of PWVs. Assessment of segmental PWV as a surrogate of vascular stiffness in focally stented femoral arteries is feasible. PWV values across all groups were 15.6±5.2 m/s, 13.3±4.1 m/s, and 9.9±2.2 m/s in PAD patients, senior-aged volunteers, and young-adult volunteers respectively. PWV values in PAD patients were similar with those in the senior-aged volunteers group (15.6±5.2 vs. 13.3 ±4.1 years, p=0.43). However, when compared to the young-adult volunteers, PAD patients had a statistically significantly higher mean local PWV (15.6±5.2 m/s vs. 9.9±2.2 m/s, p<0.05). Results: Four-D-flow MRI sequences offering high spatial and temporal resolution enables quantification of flow velocity measurements and estimation of PWVs. Assessment of segmental PWV as a surrogate of vascular stiffness in focally stented femoral arteries is feasible. PWV values across all groups were 15.6±5.2 m/s, 13.3±4.1 m/s, and 9.9±2.2 m/s in PAD patients, senior-aged volunteers, and young-adult volunteers respectively. PWV values in PAD patients were similar with those in the senior-aged volunteers group (15.6±5.2 vs. 13.3 ±4.1 years, p=0.43). However, when compared to the young-adult volunteers, PAD patients had a statistically significantly higher mean local PWV (15.6±5.2 m/s vs. 9.9±2.2 m/s, p<0.05). Conclusions: Calculating segmental PWV in the femoral arteries is feasible in PAD patients with focally stented FP arteries. PWV values in PAD patients were similar to those in senior-aged volunteers, both of which were higher than in young-adult volunteers.
- Published
- 2021
- Full Text
- View/download PDF
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