Changes in endocan and dermatan sulfate are associated with biomechanical properties of abdominal aortic wall during aneurysm expansion and rupture

BACKGROUND AND AIMS

The study aimed to assess the potential of proteoglycans (PG) and collagens as serological biomarkers in the abdominal aortic aneurysm (AAA). Furthermore, we investigated the underlying mechano-biological interactions and signaling pathways.

METHODS

Tissue and serum samples from patients with ruptured AAA (rAAA, n=29), elective AAA (eAAA, n=78), and healthy individuals (n=8) were evaluated by histology, immunohistochemistry and Enzyme-linked Immunosorbent Assay (ELISA), mechanical properties were assessed by tensile tests. Regulatory pathways were determined by membrane-based sandwich immunoassay.

RESULTS

In AAA samples, collagen type I and III (Col1, Col3), chondroitin sulfate (CS), and dermatan sulfate (DS) were significantly increased compared to controls (3.0-, 3.2-, 1.3-, and 53-fold; p<0.01). Col1 and endocan were also elevated in the serum of AAA patients (3.6- and 6.0-fold; p<0.01), while DS was significantly decreased (2.5-fold; p<0.01). Histological scoring showed increased total PGs and focal accumulation in rAAA compared to eAAA. Tissue β-stiffness was higher in rAAA compared to eAAA (2.0-fold, p=0.02). Serum Col1 correlated with maximum tensile force and failure tension (r=0.448 and 0.333; p<0.01 and =0.02), tissue endocan correlated with α-stiffness (r=0.340; p<0.01). Signaling pathways in AAA were associated with ECM synthesis and VSMC proliferation. In particular, Src family kinases, PDGF- and EGF-related proteins seem to be involved.

CONCLUSIONS

Our findings reveal a structural association between collagen and PGs and their response to changes in mechanical loads in AAA. Particularly Col1 and endocan reflect the mechano-biological conditions of the aortic wall also in the patient's serum and might serve for AAA risk stratification.

Pleural effusion: a potential surrogate marker for higher-risk patients with acute type B aortic dissections

OBJECTIVES

Pleural effusions (PEffs) are known to occur in type B acute aortic dissection (TBAAD). We investigated the relationship between pleural effusion and the development of early or late complications following TBAAD.

METHODS

The incidence of PEff (defined as at least an obliteration of the costophrenic angle in a frontal projection) diagnosed on their initial chest X-ray in patients with TBAAD enrolled in the International Registry of Acute Aortic Dissection was examined. We analysed in-hospital outcomes and long-term survival separately for patients with and without PEffs (PEff+ versus PEff-, respectively).

RESULTS

Included were 1252 patients with TBAAD, of whom 224 (17.9%) had PEff. Compared with patients without PEff in the initial chest X-ray, these were significantly older [mean age 67 (SD: 14.7) vs 63.4 (SD: 14.2) years, P = 0.001] and more often female (42.4% vs 34.2%, P = 0.021) and had more comorbidities (known aortic aneurysm, chronic obstructive pulmonary disease, chronic renal failure, diabetes, congestive heart failure or mitral valve disease). PEff was associated with higher in-hospital mortality (16.1% vs 9.1%, P = 0.002) and increased rates of neurological complications (16.6% vs 11.1%, P = 0.029), acute renal failure (27.2% vs 19.7%, P = 0.017) and hypotension (17.4% vs 9.6%, P = 0.001). In addition, patients with PEff underwent aortic repair more frequently (44.6% vs 32.5%, P < 0.001). In the long-term patients with PEff showed lower 5-year post-discharge survival (67.6% vs 77.6%, P = 0.004). Multivariable analysis with propensity-matched data showed that PEff was not an independent risk factor for in-hospital mortality (odds ratio 1.9, 95% CI 0.8-4.4, P = 0.141).

CONCLUSIONS

Patients with TBAAD and evidence of PEff showed a higher in-hospital mortality, are more likely to develop additional in-hospital complications and have a decreased likelihood of survival during follow-up. However, according to propensity-matched analysis, PEff remained not as an independent predictor of worse outcome but might serve as an early surrogate marker to identify higher-risk patients.

Chitinase 3 like 1 is a regulator of smooth muscle cell physiology and atherosclerotic lesion stability

AIMS

Atherosclerotic cerebrovascular disease underlies the majority of ischaemic strokes and is a major cause of death and disability. While plaque burden is a predictor of adverse outcomes, plaque vulnerability is increasingly recognized as a driver of lesion rupture and risk for clinical events. Defining the molecular regulators of carotid instability could inform the development of new biomarkers and/or translational targets for at-risk individuals.

METHODS AND RESULTS

Using two independent human endarterectomy biobanks, we found that the understudied glycoprotein, chitinase 3 like 1 (CHI3L1), is up-regulated in patients with carotid disease compared to healthy controls. Further, CHI3L1 levels were found to stratify individuals based on symptomatology and histopathological evidence of an unstable fibrous cap. Gain- and loss-of-function studies in cultured human carotid artery smooth muscle cells (SMCs) showed that CHI3L1 prevents a number of maladaptive changes in that cell type, including phenotype switching towards a synthetic and hyperproliferative state. Using two murine models of carotid remodelling and lesion vulnerability, we found that knockdown of Chil1 resulted in larger neointimal lesions comprised by de-differentiated SMCs that failed to invest within and stabilize the fibrous cap. Exploratory mechanistic studies identified alterations in potential downstream regulatory genes, including large tumour suppressor kinase 2 (LATS2), which mediates macrophage marker and inflammatory cytokine expression on SMCs, and may explain how CHI3L1 modulates cellular plasticity.

CONCLUSION

CHI3L1 is up-regulated in humans with carotid artery disease and appears to be a strong mediator of plaque vulnerability. Mechanistic studies suggest this change may be a context-dependent adaptive response meant to maintain vascular SMCs in a differentiated state and to prevent rupture of the fibrous cap. Part of this effect may be mediated through downstream suppression of LATS2. Future studies should determine how these changes occur at the molecular level, and whether this gene can be targeted as a novel translational therapy for subjects at risk of stroke.

Optimal management of asymptomatic carotid stenosis in 2021: the jury is still out. An International, multispecialty, expert review and position statement

OBJECTIVES

The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement is to reconcile the conflicting views on the topic.

MATERIALS AND METHODS

A literature review was performed with a focus on data from recent studies.

RESULTS

Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients <75 years and microembolic signals on transcranial Doppler. There is growing evidence that 80-99% ACS indicate a higher stroke risk than 50-79% stenoses.

CONCLUSIONS

Although aggressive risk factor control and BMT should be implemented in all ACS patients, several high-risk features that may increase the risk of a future cerebrovascular event are now documented. Consequently, some guidelines recommend a prophylactic carotid intervention in high-risk patients to prevent future cerebrovascular events. Until the results of the much-anticipated randomized controlled trials emerge, the jury is still out regarding the optimal management of ACS patients.

Concomitantly discovered visceral artery aneurysms do rarely grow during cancer therapy

Visceral artery aneurysms (VAA) are a rare entity of arterial aneurysms with the imminent threat of rupture. The impact of cancer and chemotherapy on the growth of VAAs is unknown. A retrospective dual center cohort study of patients with concomitant VAA and different types of cancer was conducted and the impact of various chemotherapeutic agents on VAA growth was studied by sequential CT analysis. For comparison, a non-cancer all comer cohort with VAAs and no cancer was studied to compare different growth rates. The primary endpoint was aneurysm progress or regression >1.75 mm. Chi-square test, Fisher's exact test and Mann-Whitney test was used for statistical comparison. In the 17-year-period from January 2003 to March 2020, 59 patients with 30 splenic artery aneurysms, 14 celiac trunk aneurysms, 11 renal artery aneurysms and 4 other VAA and additional malignancy were identified. 20% of patients suffered from prostate cancer, the rest were heterogeneous. The most prevalent chemotherapies were alkylating agents (23%), antimetabolites (14%) and mitose inhibitors (10%). Eight patients had relevant growth of their VAA and one patient showed diameter regression (average growth rate 0.1 ± 0.5 mm/year). Twenty-nine patients with 14 splenic, 11 RAAs (seven right) and 4 celiac trunk aneurysms were available in the non-cancer comparison cohort (average growth rate 0.5 ± 0.9 mm/year, p = 0.058). However, the growth rate of patients receiving operative treatment for relevant VAA growth was significantly higher (p = 0.004). VAAs grow rarely, and rather slow. Cancer and/or chemotherapy do not significantly influence the annual growth rate. Additional control examinations seem unnecessary.

Translating mouse models of abdominal aortic aneurysm to the translational needs of vascular surgery

Introduction

Abdominal aortic aneurysm (AAA) is a condition that has considerable socioeconomic impact and an eventual rupture is associated with high mortality and morbidity. Despite decades of research, surgical repair remains the treatment of choice and no medical therapy is currently available. Animal models and, in particular, murine models, of AAA are a vital tool for experimental in vivo research. However, each of the different models has individual limitations and provide only partial mimicry of human disease. This narrative review addresses the translational potential of the available mouse models, highlighting unanswered questions from a clinical perspective. It is based on a thorough presentation of the available literature and more than a decade of personal experience, with most of the available models in experimental and translational AAA research.

Results

From all the models published, only the four inducible models, namely the angiotensin II model (AngII), the porcine pancreatic elastase perfusion model (PPE), the external periadventitial elastase application (ePPE), and the CaCl₂ model have been widely used by different independent research groups. Although the angiotensin II model provides features of dissection and aneurysm formation, the PPE model shows reliable features of human AAA, especially beyond day 7 after induction, but remains technically challenging. The translational value of ePPE as a model and the combination with β-aminopropionitrile to induce rupture and intraluminal thrombus formation is promising, but warrants further mechanistic insights. Finally, the external CaCl₂ application is known to produce inflammatory vascular wall thickening. Unmet translational research questions include the origin of AAA development, monitoring aneurysm growth, gender issues, and novel surgical therapies as well as novel nonsurgical therapies.

Conclusion

New imaging techniques, experimental therapeutic alternatives, and endovascular treatment options provide a plethora of research topics to strengthen the individual features of currently available mouse models, creating the possibility of shedding new light on translational research questions.

Long Noncoding RNA MIAT Controls Advanced Atherosclerotic Lesion Formation and Plaque Destabilization

Supplemental Digital Content is available in the text.

Long noncoding RNAs (lncRNAs) are important regulators of biological processes involved in vascular tissue homeostasis and disease development. The present study assessed the functional contribution of the lncRNA myocardial infarction-associated transcript (MIAT) to atherosclerosis and carotid artery disease.

Proximal False Lumen Thrombosis is Associated with Low False Lumen Pressure and Fewer Complications in Type B Aortic Dissection

BACKGROUND

Improved risk stratification is a key priority for type B aortic dissection (TBAD). Partial false lumen thrombus morphology is an emerging predictor of complications however, partial thrombosis is poorly defined and its evaluation in clinical studies is inconsistent.

PURPOSE

This work aims to characterise hemodynamic pressure in TBAD and determine how pressure relates to false lumen thrombus morphology and clinical events.

METHODS

Retrospective admission computed tomography angiography of 69 patients with acute TBAD was used to construct three-dimensional computational models for simulation of cyclical blood flow and calculation of pressure. Patients were categorised based on false lumen thrombus morphology: minimal; proximal; distal; or extensive thrombosis. Linear regression analysis compared the luminal pressure difference between the true and false lumen for each morphology group. The impact of morphology classification on acute complications within 14 days was studied using logistic regression adjusted for clinical parameters. A survival analysis for adverse aortic events at one-year was also performed using Cox regression.

RESULTS

44 patients experienced acute complications and 45 had an adverse aortic event at one-year. Mean (±standard deviation) age was 62.6 (±12.6) years and 75.4% were male. Compared to patients with minimal thrombosis, those with proximal thrombosis had reduced false lumen pressure by 10.1mmHg (95% CI 4.3-15.9mmHg, p=.001). Individuals that did not experience an acute complication had reduced relative false lumen pressure (-6.35mmHg vs -0.62mmHg, p=.03). Proximal thrombosis was associated with fewer acute complications (OR 0.17, 95% CI 0.04-0.60 p=.01) and one-year adverse aortic events (HR 0.36, 95% CI 0.16-0.80, p=.01).

CONCLUSIONS

Proximal false lumen thrombosis is a marker of reduced false lumen pressure. This may explain how proximal false lumen thrombosis appears protective of acute complications (refractory hypertension or pain, aortic rupture, visceral or limb malperfusion and acute expansion) and adverse aortic events within the first year.

A systematic review and meta-analysis on early mortality after abdominal aortic aneurysm repair in females in urgent and elective setting

OBJECTIVE

Females represent a group of patients with higher mortality after abdominal aortic aneurysm (AAA), endovascular (EVAR) or open (OSR), repair. This systematic review aimed to evaluate the 30-day mortality after AAA repair in females, comparing both EVAR and OSR, in elective and urgent settings.

METHODS

The protocol of the review was registered to the PROSPERO (CRD42021242686). A search of the English literature was conducted, using PubMed, EMBASE and CENTRAL databases, from inception to March 5, 2021, using the Systematic Reviews and Meta-Analysis guidelines (PRISMA). Only studies reporting on 30-day mortality of AAA repair, in urgent and elective setting, comparing EVAR and OSR, in female population were eligible. Patients were stratified according to the need for elective or urgent repair. Symptomatic and ruptured cases were included into the urgent group. Individual studies were assessed for risk of bias using the ROBINS-I tool. The GRADE approach was used to evaluate the quality of evidence. The primary outcome was 30-day mortality after AAA repair in the female population, comparing EVAR and OSR. The outcomes were summarized as odds ratio along with their 95% confidence intervals (CI), through a paired meta-analysis.

RESULTS

Eight studies reported data on 30-day mortality following AAA repair. A total of 56,982 females (22,995 EVAR vs. 33,987 OSR) were included. A significantly reduced total 30-day mortality rate was recorded among females that underwent EVAR compared to OSR (OR, 0.25; 95% CI, 0.23-0.27; P<.001, Ι²=86%). Also a reduced 30-day mortality was found in females that underwent elective EVAR compared to OSR (OR, 0.37; 95% CI, 0.33-0.41; P< .001, Ι²=48%). Despite that OSR was more frequently offered in the urgent setting (OR, 0.21; 95% CI, 0.19-0.23; P< .001, Ι²=84%), EVAR was associated with a reduced 30-day mortality (OR, 0.48; 95% CI, 0.40-0.57; P<.001, Ι²=0%).

CONCLUSIONS

In females, EVAR is associated with lower 30-day mortality in both elective and urgent AAA repair, although it appears as less likely to be offered in the setting of urgent AAA repair.

Optimal Management of Asymptomatic Carotid Stenosis in 2021: The Jury is Still Out. An International, Multispecialty, Expert Review and Position Statement

OBJECTIVES

The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement is to reconcile the conflicting views on the topic.

MATERIALS AND METHODS

A literature review was performed with a focus on data from recent studies.

RESULTS

Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients < 75 years and microembolic signals on transcranial Doppler. There is growing evidence that 80-99% ACS indicate a higher stroke risk than 50-79% stenoses.

CONCLUSIONS

Although aggressive risk factor control and BMT should be implemented in all ACS patients, several high-risk features that may increase the risk of a future cerebrovascular event are now documented. Consequently, some guidelines recommend a prophylactic carotid intervention in high-risk patients to prevent future cerebrovascular events. Until the results of the much-anticipated randomized controlled trials emerge, the jury is still out regarding the optimal management of ACS patients.

Successful implementation of best medical treatment for patients with asymptomatic carotid artery stenosis within a randomized controlled trial (SPACE-2)

Background

Asymptomatic carotid artery stenosis (ACS) can be treated with carotid endarterectomy (CEA), carotid artery stenting (CAS), or best medical treatment (BMT) only. For all treatment options, optimization of vascular risk factors such as arterial hypertension, hyperlipidemia, smoking, obesity, and insufficient physical activity is essential. Data on adherence to BMT and lifestyle modification in patients with ACS are sparse. The subject of this investigation is the implementation and quality of risk factor adjustment in the context of a randomized controlled trial.

Methods

A total of 513 patients in the prematurely terminated, randomized, controlled, multicenter SPACE-2 trial (ISRCTN 78592017) were analyzed within one year after randomization into 3 groups (CEA, CAS, and BMT only) for implementation of prespecified BMT recommendations and lifestyle modifications. Measurement time points were the screening visit and visits after one month (D30), 6 months (M6), and one year (A1). Differences between groups and follow-up visits (FUVs) relative to the screening visit were investigated.

Findings

For all FUVs, a significant increase in statin medication (91% at A1; p < 0.0001) was demonstrated to be associated with a significant decrease (p < 0.01) in cholesterol levels (median 167 mg/dl at A1) and LDL cholesterol levels (median 93 mg/dl at A1). The lowest cholesterol levels were achieved by patients in the BMT group. Seventy-eight percent of all patients reached predefined target cholesterol levels (< 200 mg/dl), with significantly better rates in the BMT group (p = 0.036 at D30). Furthermore, a significant decrease in arterial blood pressure at all FUVs (p < 0.05) was associated with a significant increase in antihypertensive medication (96% at A1, p < 0.0001). However, only 28% of patients achieved the predefined treatment goal of a systolic blood pressure of ≤ 130 mmHg. Forty-two of a total of 100 smokers at the screening visit quit smoking within one year, resulting in a significant increase in nonsmokers at all FUVs (p < 0.0001). Recommended HbA1c levels (< 7%) were achieved in 82% without significant changes after one year. Only 7% of obese (BMI > 25) patients achieved sufficient weight reduction after one year without significant changes at all FUVs (median BMI 27 at A1; p = 0.1201). The BMT group showed significantly (p = 0.024) higher rates of adequate physical activity than the intervention groups. Furthermore, after one year, the BMT group showed a comparatively significantly better implementation of risk factor modification (77%; p = 0.027) according to the treating physician.

Interpretation

SPACE-2 demonstrated sustained improvement in the noninterventional management of vascular risk factors in patients treated in a clinical trial by general practitioners, internists and neurologists. The best implemented treatment targets were a reduction in cholesterol and HbA1c levels. In this context, a significant increase in statin use was demonstrated. Blood pressure control missed its target but was significantly reduced by intensification of antihypertensive medication. Patients on BMT only had better adjusted lipid parameters and were more physically active. However, all groups failed to achieve sufficient weight reduction. Due to insufficient patient recruitment, the results must be interpreted cautiously.

Trial registration: ISRCTN Registry, ISRCTN78592017, Registered 16 June 2007, https://www.isrctn.com/search?q=78592017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42466-021-00153-w.

Multispectral optoacoustic tomography of lipid and hemoglobin contrast in human carotid atherosclerosis

Several imaging techniques aim at identifying features of carotid plaque instability but come with limitations, such as the use of contrast agents, long examination times and poor portability. Multispectral optoacoustic tomography (MSOT) employs light and sound to resolve lipid and hemoglobin content, both features associated with plaque instability, in a label-free, fast and highly portable way. Herein, 5 patients with carotid atherosclerosis, 5 healthy volunteers and 2 excised plaques, were scanned with handheld MSOT. Spectral unmixing allowed visualization of lipid and hemoglobin content within three ROIs: whole arterial cross-section, plaque and arterial lumen. Calculation of the fat-blood-ratio (FBR) value within the ROIs enabled the differentiation between patients and healthy volunteers (P = 0.001) and between plaque and lumen in patients (P = 0.04). Our results introduce MSOT as a tool for molecular imaging of human carotid atherosclerosis and open new possibilities for research and clinical assessment of carotid plaques.

Intraoperative completion studies in carotid endarterectomy: systematic review and meta-analysis of techniques and outcomes

Background

Declining perioperative stroke and death rates over the past 3 decades have been paralleled by an increasing use of intraoperative completion studies (ICS) following carotid endarterectomy (CEA). Techniques applied include angiography, intraoperative duplex ultrasound (IDUS), flowmetry, and angioscopy. This systematic review and meta-analysis is aiming on providing an overview of techniques and corresponding outcomes.

Methods

A PubMed based systematic literature review comprising the years 1980 through 2020 was performed using predefined keywords to identify articles on different ICS techniques. Pooled analyses and meta-analyses estimating risk ratios (RR) and 95% confidence intervals (CI) were performed to compare outcomes of different ICS modes to nonapplication of any ICS. I² values were assessed to quantify study heterogeneities.

Results

Identification of 34 studies including patients undergoing CEA with angiography (n=53,218), IDUS (n=20,030), flowmetry (n=16,812), and angioscopy (n=2,291). Corresponding rates of perioperative stroke were 1.5%, 1.8%, 3.6%, and 1.5%, perioperative stroke or death occurred in 1.7%, 1.9%, 2.2%, and 2.0%. Intraoperative surgical revision rates were 6.2%, 5.9%, and 7.9% after CEA with angiography, IDUS, and angioscopy, respectively. Compared to nonapplication of any ICS, the pooled analysis revealed angiography to be significantly associated with lower rates of stroke (RR 0.47; 95% CI, 0.36–0.62; P<0.0001) and stroke or death (RR 0.76; 95% CI, 0.70–0.83; P<0.0001). IDUS was significantly associated with lower rates of stroke (RR 0.56; 95% CI, 0.43–0.73; P<0.0001) and stroke or death (RR 0.83; 95% CI, 0.74–0.93; P=0.0018), whereas angioscopy showed a significant association with a lower stroke rate (RR 0.48; 95% CI, 0.033–0.68; P=0.0001), but no effect on the combined stroke or death rate. Angioscopy was associated with a higher intraoperative revision rate compared to angiography (RR 1.29; 95% CI, 1.07–1.54; P=0.006). The meta-analyses confirmed lower perioperative stroke or death rates for angiography (RR 0.83; 95% CI, 0.76–0.91) and IDUS (RR 0.86; 95% CI, 0.76–0.98) compared to non-application of any ICS, whereas flowmetry showed no significant association.

Conclusions

This study represents the first systematic literature review and meta-analysis on usage of ICSs in CEA. Data strongly indicate a significant beneficial effect of angiography, IDUS, and angioscopy on perioperative CEA outcomes. Any carotid surgeon should consider implementation of ICSs in his routine armamentarium.

European Stroke Organisation guideline on endarterectomy and stenting for carotid artery stenosis

Atherosclerotic stenosis of the internal carotid artery is an important cause of stroke. The aim of this guideline is to analyse the evidence pertaining to medical, surgical and endovascular treatment of patients with carotid stenosis. These guidelines were developed based on the ESO standard operating procedure and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. The working group identified relevant questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and wrote recommendations. Based on moderate quality evidence, we recommend carotid endarterectomy (CEA) in patients with ≥60-99% asymptomatic carotid stenosis considered to be at increased risk of stroke on best medical treatment (BMT) alone. We also recommend CEA for patients with ≥70-99% symptomatic stenosis, and we suggest CEA for patients with 50-69% symptomatic stenosis. Based on high quality evidence, we recommend CEA should be performed early, ideally within two weeks of the last retinal or cerebral ischaemic event in patients with ≥50-99% symptomatic stenosis. Based on low quality evidence, carotid artery stenting (CAS) may be considered in patients < 70 years old with symptomatic ≥50-99% carotid stenosis. Several randomised trials supporting these recommendations were started decades ago, and BMT, CEA and CAS have evolved since. The results of another large trial comparing outcomes after CAS versus CEA in patients with asymptomatic stenosis are anticipated in the near future. Further trials are needed to reassess the benefits of carotid revascularisation in combination with modern BMT in subgroups of patients with carotid stenosis.

European Stroke Organisation guideline on endarterectomy and stenting for carotid artery stenosis

Atherosclerotic stenosis of the internal carotid artery is an important cause of stroke. The aim of this guideline is to analyse the evidence pertaining to medical, surgical and endovascular treatment of patients with carotid stenosis. These guidelines were developed based on the ESO standard operating procedure and followed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. The working group identified relevant questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and wrote recommendations. Based on moderate quality evidence, we recommend carotid endarterectomy (CEA) in patients with ≥60-99% asymptomatic carotid stenosis considered to be at increased risk of stroke on best medical treatment (BMT) alone. We also recommend CEA for patients with ≥70-99% symptomatic stenosis, and we suggest CEA for patients with 50-69% symptomatic stenosis. Based on high quality evidence, we recommend CEA should be performed early, ideally within two weeks of the last retinal or cerebral ischaemic event in patients with ≥50-99% symptomatic stenosis. Based on low quality evidence, carotid artery stenting (CAS) may be considered in patients < 70 years old with symptomatic ≥50-99% carotid stenosis. Several randomised trials supporting these recommendations were started decades ago, and BMT, CEA and CAS have evolved since. The results of another large trial comparing outcomes after CAS versus CEA in patients with asymptomatic stenosis are anticipated in the near future. Further trials are needed to reassess the benefits of carotid revascularisation in combination with modern BMT in subgroups of patients with carotid stenosis.

Lenvatinib halts aortic aneurysm growth by restoring smooth muscle cell contractility

Abdominal aortic aneurysm (AAA) is a disease with high morbidity and mortality, especially when ruptured. The rationale of this study was to evaluate the repurposing of lenvatinib, a multi–tyrosine kinase inhibitor, in limiting experimental AAA growth targeting vascular smooth muscle cells (VSMCs) and angiogenesis. We applied systemic and local lenvatinib treatment to elastase-induced murine aortic aneurysms, and RNA profiling identified myosin heavy chain 11 (Myh11) as the most deregulated transcript. Daily oral treatment substantially reduced aneurysm formation in 2 independent mouse models. In addition, a large animal aneurysm model in hypercholesterolemic low-density lipoprotein receptor–knockout (LDLR^–/–) Yucatan minipigs was applied to endovascularly deliver lenvatinib via drug-eluting balloons (DEBs). Here, a single local endovascular delivery blocked AAA progression successfully compared with a DEB-delivered control treatment. Reduced VSMC proliferation and a restored contractile phenotype were observed in animal tissues (murine and porcine), as well as AAA patient-derived cells. Apart from increasing MYH11 levels, lenvatinib reduced downstream ERK signaling. Hence, lenvatinib is a promising therapy to limit aortic aneurysm expansion upon local endovascular delivery. The tyrosine kinase inhibitor was able to positively affect pathways of key relevance to human AAA disease, even in a potentially new local delivery using DEBs.

Management of patients with asymptomatic carotid stenosis may need to be individualized: a multidisciplinary call for action. Republication of J Stroke 2021;23:202-212

The optimal management of patients with asymptomatic carotid stenosis (ACS) is the subject of extensive debate. According to the 2017 European Society for Vascular Surgery guidelines, carotid endarterectomy should (Class IIa; Level of Evidence: B) or carotid artery stenting may be considered (Class IIb; Level of Evidence: B) in the presence of one or more clinical/imaging characteristics that may be associated with an increased risk of late ipsilateral stroke (e.g. silent embolic infarcts on brain computed tomography/magnetic resonance imaging, progression in the severity of ACS, a history of contralateral transient ischemic attack/stroke, microemboli detection on transcranial Doppler, etc.), provided documented perioperative stroke/death rates are <3% and the patient's life expectancy is >5 years. Besides these clinical/imaging characteristics, there are additional individual, ethnic/racial or social factors that should probably be evaluated in the decision process regarding the optimal management of these patients, such as individual patient needs/patient choice, patient compliance with best medical treatment, patient sex, culture, race/ethnicity, age and comorbidities, as well as improvements in imaging/operative techniques/outcomes. The present multispecialty position paper will present the rationale why the management of patients with ACS may need to be individualized.

Contralateral Stenosis and Echolucent Plaque Morphology are Associated with Elevated Stroke Risk in Patients Treated with Asymptomatic Carotid Artery Stenosis within a Controlled Clinical Trial (SPACE-2)

BACKGROUND

Asymptomatic carotid artery stenosis (ACS) has a low risk of stroke. To achieve an advantage over noninterventional best medical treatment (BMT), carotid endarterectomy (CEA) or carotid artery stenting (CAS) must be performed with the lowest possible risk of stroke. Therefore, an analysis of risk-elevating factors is essential. Grade of ipsilateral and contralateral stenosis as well as plaque morphology are known risk factors in ACS.

METHODS

The randomized, controlled, multicenter SPACE-2 trial had to be stopped prematurely after recruiting 513 patients. 203 patients were randomized to CEA, 197 to CAS, and 113 to BMT. Within one year, risk factors such as grade of stenosis and plaque morphology were analyzed.

RESULTS

Grade of contralateral stenosis (GCS) was higher in patients with any stroke (50%^ECST vs. 20%^ECST; p=0.012). Echolucent plaque morphology was associated with any stroke on the day of intervention (OR 5.23; p=0.041). In the periprocedural period, any stroke was correlated with GCS in the CEA group (70%^ECST vs. 20%^ECST; p=0.026) and with echolucent plaque morphology in the CAS group (6% vs. 1%; p=0.048). In multivariate analysis, occlusion of the contralateral carotid artery (CCO) was associated with risk of any stroke (OR 7.00; p=0.006), without heterogeneity between CEA and CAS.

CONCLUSION

In patients with asymptomatic carotid artery stenosis, GCS, CCO, as well as echolucent plaque morphology were associated with a higher risk of cerebrovascular events. The risk of stroke in the periprocedural period was increased by GCS in CEA and by echolucent plaque in CAS. Due to small sample size, results must be interpreted carefully.

Acute abdominal aortic occlusion-a 16-year single-center experience

BACKGROUND

Acute abdominal aortic occlusion (AAO) is a rare vascular emergency associated with high morbidity and mortality. In the present study, we analyzed the clinical management and outcomes for a consecutive patient series during a 16-year period.

METHODS

We included all patients with an acute AAO and bilateral acute limb ischemia who had been treated between 2004 and 2019. Patients with dissection, aneurysm rupture, or chronic occlusive disease were excluded. The patient characteristics, surgical procedures, and outcomes were extracted retrospectively from a prospective aortic database, electronic patient files, and outpatient examination records. The extent of ischemia was classified according to the TASC II (Inter-Society Consensus for the Management of Peripheral Arterial Disease) section on acute limb ischemia. The primary endpoints were 30-day mortality (safety endpoint) and the combined 6-month amputation and/or death rate (efficacy endpoint). The follow-up outcomes, amputation rates, and 30-day complications were evaluated as secondary endpoints. The patient cohort was divided into four 4-year groups (2004-2007, 2008-2011, 2012-2015, 2016-2019) to assess the outcome changes over time. Statistical analysis included χ² tests and univariate and linear regression analyses.

RESULTS

A total of 74 patients (57% male; median age, 64.5 years) with an acute AAO were identified. Arterial thrombosis was the most common etiology (66%). The extent of ischemia was TASC I, IIa, IIb, and III in 7%, 39%, 40%, and 14%, respectively. The patient numbers had increased significantly over time (P = .016). Of the patients, 42% had undergone open transfemoral recanalization (including hybrid procedures), 35% open aortic surgery, 15% extra-anatomic bypass surgery, and 5% (four patients) endovascular therapy alone. The overall 30-day mortality rate was 23%, and the 6-month amputation and/or death rate was 43%. The 30-day mortality rate had declined significantly from 54% for 2004 to 2007 to 10% for 2011 to 2015 (odds ratio [OR], 0.10; 95% confidence interval [CI], 0.001-0.52) and 20% for 2016 to 2019 (OR, 0.21; 95% CI, 0.05-0.90), a statistically nonsignificant trend showing that the relative decline in the use of open aortic procedures was associated with decreased 30-day mortality (P = .06). Univariate analysis indicated that elevated serum lactate on admission (OR, 3.33; 95% CI, 1.06-10.48) and an advanced stage of limb ischemia (OR, 4.33), were strongly associated with an increased 30-day mortality rate. The incidence of severe postoperative systemic complications also indicated a greater incidence of both primary endpoints. The 6-month amputation and/or mortality rates were also affected by the presence of atrial fibrillation (OR, 3.63; 95% CI, 1.34-9.79) and increased patient age (OR, 3.96; 95% CI, 1.49-10.53).

CONCLUSIONS

Acute AAO remains a life-threatening emergency. Immediate transfemoral open or endovascular techniques should be preferred, if technically possible and proper intraoperative imaging is available.

Decreasing Spatial Variability of Individual Watershed Areas by Revascularization Therapy in Patients With High-Grade Carotid Artery Stenosis

BACKGROUND

Carotid artery stenosis can impair cerebral hemodynamics especially within watershed areas (WSAs) between vascular territories. WSAs can shift because of collateral flow, which may be an indicator for increased hemodynamic implications and hence higher risk for ischemic stroke. However, whether revascularization treatment can reverse the spatial displacement of individual WSAs (iWSAs) and impaired hemodynamics remains unknown.

HYPOTHESIS

That iWSAs spatially normalize because of hemodynamic improvement resulting from revascularization treatment.

STUDY TYPE

Prospective.

POPULATION

Sixteen patients with unilateral, high-grade carotid artery stenosis confirmed by duplex ultrasonography and 17 healthy controls.

FIELD STRENGTH/SEQUENCES

A 3 T-magnetization-prepared rapid acquisition gradient echo (MPRAGE), gradient-echo echo planar dynamic susceptibility contrast (DSC), and fluid-attenuated inversion recovery (FLAIR) sequences. Additionally, contrast-enhanced 3D gradient echo magnetic resonance angiography (MRA) and diffusion-tensor imaging (DTI) spin-echo echo planar imaging were performed.

ASSESSMENT

iWSAs were delineated by a recently proposed procedure based on time-to-peak maps from DSC perfusion MRI, which were also used to evaluate perfusion delay. We spatially compared iWSAs and perfusion delay before and after treatment (endarterectomy or stenting). Additionally, the Circle of Willis collateralization status was evaluated, and basic cognitive testing was conducted.

STATISTICAL TESTS

Statistical tests included two-sample t-tests and Chi-squared tests. A P value < 0.05 was considered to be statistically significant.

RESULTS

After revascularization, patients showed a significant spatial shift of iWSAs and significantly reduced perfusion delay ipsilateral to the stenosis. Spatial shift of iWSA (P = 0.007) and cognitive improvement (P = 0.013) were more pronounced in patients with poor pre-existing collateralization. Controls demonstrated stable spatial extent of iWSAs (P = 0.437) and symmetric perfusion delays between hemispheres over time (P = 0.773).

DATA CONCLUSION

These results demonstrate the normalization of iWSA and impaired hemodynamics after revascularization in patients with high-grade carotid artery stenosis.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Management of Patients with Asymptomatic Carotid Stenosis May Need to Be Individualized: A Multidisciplinary Call for Action

The optimal management of patients with asymptomatic carotid stenosis (ACS) is the subject of extensive debate. According to the 2017 European Society for Vascular Surgery guidelines, carotid endarterectomy should (Class IIa; Level of Evidence: B) or carotid artery stenting may be considered (Class IIb; Level of Evidence: B) in the presence of one or more clinical/imaging characteristics that may be associated with an increased risk of late ipsilateral stroke (e.g., silent embolic infarcts on brain computed tomography/magnetic resonance imaging, progression in the severity of ACS, a history of contralateral transient ischemic attack/stroke, microemboli detection on transcranial Doppler, etc.), provided documented perioperative stroke/death rates are <3% and the patient’s life expectancy is >5 years. Besides these clinical/imaging characteristics, there are additional individual, ethnic/racial or social factors that should probably be evaluated in the decision process regarding the optimal management of these patients, such as individual patient needs/patient choice, patient compliance with best medical treatment, patient sex, culture, race/ethnicity, age and comorbidities, as well as improvements in imaging/operative techniques/outcomes. The present multispecialty position paper will present the rationale why the management of patients with ACS may need to be individualized.

Sex-Based Aortic Dissection Outcomes From the International Registry of Acute Aortic Dissection

BACKGROUND

Worse outcomes have been reported for women with type A acute aortic dissection (TAAD). We sought to determine sex-specific operative approaches and outcomes for TAAD in the current era.

METHODS

The Interventional Cohort (IVC) of the International Registry of Acute Aortic Dissection (IRAD) database was queried to explore sex differences in presentation, operative approach, and outcomes. Multivariable logistic regression was performed to identify adjusted outcomes in relation to sex.

RESULTS

Women constituted approximately one-third (34.3%) of the 2823 patients and were significantly older than men (65.4 vs 58.6 years, P < .001). Women were more likely to present with intramural hematoma, periaortic hematoma, or complete or partial false lumen thrombosis (all P < .05) and more commonly had hypotension or coma (P = .001). Men underwent a greater proportion of Bentall, complete arch, and elephant trunk procedures (all P < .01). In-hospital mortality during the study period was higher in women (16.7% vs 13.8%, P = .039). After adjustment, female sex trended towards higher in-hospital mortality overall (odds ratio, 1.40; P = .053) but not in the last decade of enrollment (odds ratio, 0.93; P = .807). Five-year mortality and reintervention rates were not significantly different between the sexes.

CONCLUSIONS

In-hospital mortality remains higher among women with TAAD but demonstrates improvement in the last decade. Significant differences in presentation were noted in women, including older age, distinct imaging findings, and greater evidence of malperfusion. Although no distinctions in 5-year mortality or reintervention were observed, a tailored surgical approach should be considered to reduce sex disparities in early mortality rates for TAAD.

[Relationship between regional settlement structure and hospital incidence, type of therapy and mortality of non-ruptured abdominal aortic aneurysms]

INTRODUCTION

In Germany, the regional settlement structure is heterogenous, ranging from densely populated cities with a tight network of vascular health care to large regions in which access to health care is limited in terms of space and time. Therefore, the aim of this secondary data analysis was to investigate the association between the settlement structure of the patient's home district (KT), and the hospital incidence, type of therapy, and mortality of non-ruptured abdominal aortic aneurysms (nrAAA).

METHODS

The microdata of the DRG statistics of the Federal Statistical Office for the years 2005-2014 were evaluated. All patients with nrAAA (ICD-10 Code I71.4) who were admitted to a German hospital and treated by open surgery and endovascular repair were included. Classification of treatment was based on the German Operation and Procedure Code. Patients were grouped according to the settlement structure of their home district defined by the Federal Institute for Research on Building, Urban Affairs and Spatial Development (KT1 independent city, KT2 urban district, KT3 rural district, KT4 sparsely populated region). The age-, sex- and risk-adjusted association between the type of settlement structure and in-hospital mortality was analysed using a multivariable multi-level regression model. The Elixhauser co-morbidity score validated for administrative data was used for risk adjustment.

RESULTS

Of 95,452 cases included, 88 % were men. Mean age was 72 years. There were 28,970 (30 %) patients in KT1, 37,759 (40 %) in KT2, 14,442 (15 %) in KT3 and 14,281 (15 %) in KT4. The hospital incidence was 12.4 per 100,000 inhabitants in KT1, 11.8 in KT2, 10.8 in KT3 and 11.2 in KT4 (p <0.001, falling trend). The proportion of EVAR treatment was 56 % in KT1, 54 % in KT2, 57 % KT3, and 59 % in KT4 (p <0.001, increasing trend). The raw hospital mortality of patients from KT1 to KT4 was 3.4 %, 3.4 %, 3.2 % and 3.6 %, respectively (p=0.553 for trend). The multivariable regression analysis revealed no statistically significant association between the KT and hospital mortality (KT1=reference, RR KT2=0.97 [95% CI 0.79-1.15], RR KT3=0.98 [0.81-1.14], RR KT4=0.98 [0.86-1.11]).

CONCLUSIONS

The study shows that both the hospital incidence and the type of therapy (endovascular vs. open) differed between the settlement structural district types, but there is no urban-rural gap regarding in-hospital mortality of treated nrAAA.

Editor's Choice - Distribution of Care and Hospital Incidence of Carotid Endarterectomy and Carotid Artery Stenting: A Secondary Analysis of German Hospital Episode Data

OBJECTIVE

This is a description of the German healthcare landscape regarding carotid artery disease, assessment of hospital incidence time courses for carotid endarterectomy (CEA) and carotid artery stenting (CAS), and simulation of potential effects of minimum hospital caseload requirements for CEA and CAS.

METHODS

The study is a secondary data analysis of diagnosis related group statistics data (2005-2016), provided by the German Federal Statistical Office. Cases encoded by German operation procedure codes for CEA or CAS and by International Classification of Diseases (ICD-10) codes for carotid artery disease were included. Hospitals were categorised into quartiles according to annual caseloads. Linear distances to the closest hospital fulfilling hypothetical caseload requirements were calculated.

RESULTS

A total of 132 411 and 33 709 patients treated with CEA and CAS from 2012 to 2016 were included. CEA patients had lower rates of myocardial infarction (1.4% vs. 1.8%) and death (1.2% vs. 4.0%), and CAS patients were more often treated after emergency admission (38.1% vs. 27.1%). Age standardised annual hospital incidences were 67.2 per 100 000 inhabitants for CEA and 16.3 per 100 000 inhabitants for CAS. The incidence for CEA declined from 2005 to 2016, with CAS rising again until 2016 after having declined from 2010 to 2013. Regarding distance from home to hospital, centres offering CEA are distributed more homogeneously across Germany, compared with those performing CAS. Hypothetical introduction of minimum annual caseloads (> 20 for CEA; > 10 for CAS) imply that 75% of the population would reach their hospital after travelling 45 km for CEA and 70 km for CAS.

CONCLUSION

Differences in spatial distribution mean that statutory minimum annual caseloads would have a greater impact on CAS accessibility than CEA in Germany. Presumably because of a decline in carotid artery disease and a transition towards individualised therapy for asymptomatic patients, hospital incidence for CEA has been declining.

Multicompartmental non-invasive sensing of postprandial lipemia in humans with multispectral optoacoustic tomography

OBJECTIVE

Postprandial lipid profiling (PLP), a risk indicator of cardiometabolic disease, is based on frequent blood sampling over several hours after a meal, an approach that is invasive and inconvenient. Non-invasive PLP may offer an alternative for disseminated human monitoring. Herein, we investigate the use of clinical multispectral optoacoustic tomography (MSOT) for non-invasive, label-free PLP via direct lipid-sensing in human vasculature and soft tissues.

METHODS

Four (n = 4) subjects (3 females and 1 male, age: 28 ± 7 years) were enrolled in the current pilot study. We longitudinally measured the lipid signals in arteries, veins, skeletal muscles, and adipose tissues of all participants at 30-min intervals for 6 h after the oral consumption of a high-fat meal.

RESULTS

Optoacoustic lipid-signal analysis showed on average a 63.4% intra-arterial increase at ~ 4 h postprandially, an 83.9% intra-venous increase at ~ 3 h, a 120.8% intra-muscular increase at ~ 3 h, and a 32.8% subcutaneous fat increase at ~ 4 h.

CONCLUSION

MSOT provides the potential to study lipid metabolism that could lead to novel diagnostics and prevention strategies by label-free, non-invasive detection of tissue biomarkers implicated in cardiometabolic diseases.

Editor's Choice - Risk of Stroke before Revascularisation in Patients with Symptomatic Carotid Stenosis: A Pooled Analysis of Randomised Controlled Trials

OBJECTIVE

Current guidelines recommending rapid revascularisation of symptomatic carotid stenosis are largely based on data from clinical trials performed at a time when best medical therapy was potentially less effective than today. The risk of stroke and its predictors among patients with symptomatic carotid stenosis awaiting revascularisation in recent randomised controlled trials (RCTs) and in medical arms of earlier RCTs was assessed.

METHODS

The pooled data of individual patients with symptomatic carotid stenosis randomised to stenting (CAS) or endarterectomy (CEA) in four recent RCTs, and of patients randomised to medical therapy in three earlier RCTs comparing CEA vs. medical therapy, were compared. The primary outcome event was any stroke occurring between randomisation and treatment by CAS or CEA, or within 120 days after randomisation.

RESULTS

A total of 4 754 patients from recent trials and 1 227 from earlier trials were included. In recent trials, patients were randomised a median of 18 (IQR 7, 50) days after the qualifying event (QE). Twenty-three suffered a stroke while waiting for revascularisation (cumulative 120 day risk 1.97%, 95% confidence interval [CI] 0.75 - 3.17). Shorter time from QE until randomisation increased stroke risk after randomisation (χ² = 6.58, p = .011). Sixty-one patients had a stroke within 120 days of randomisation in the medical arms of earlier trials (cumulative risk 5%, 95% CI 3.8 - 6.2). Stroke risk was lower in recent than earlier trials when adjusted for time between QE and randomisation, age, severity of QE, and degree of carotid stenosis (HR 0.47, 95% CI 0.25 - 0.88, p = .019).

CONCLUSION

Patients with symptomatic carotid stenosis enrolled in recent large RCTs had a lower risk of stroke after randomisation than historical controls. The added benefit of carotid revascularisation to modern medical care needs to be revisited in future studies. Until then, adhering to current recommendations for early revascularisation of patients with symptomatic carotid stenosis considered to require invasive treatment is advisable.

Diagnosis, Treatment and Follow-up in Extracranial Carotid Stenosis

BACKGROUND

Around 15% of cerebral ischemias are caused by lesions of the extracranial carotid artery. The goal of this guideline is to provide evidence- and consensus-based recommendations for the management of patients with extracranial carotid stenoses throughout Germany and Austria.

METHODS

A systematic literature search (1990-2019) and methodical assessment of existing guidelines and systematic reviews; consensus-based answers to 37 key questions with evidence-based recommendations.

RESULTS

The prevalence of extracranial carotid artery stenoses is around 4% overall, higher from the age of 65 years. The most important examination modality is duplex sonography. Randomized trials have shown that carotid endarterectomy (CEA) significantly reduces the 5-year risk of stroke in patients with 60-99 % asymptomatic stenoses (absolute risk reduction [ARR] 4.1% over 5 years, number needed to treat [NNT] 24) or 50-99% symptomatic stenoses (50-69%: ARR 4.6 % over 5 years, NNT 22; 70-99%: 15.9 % over 5 years, NNT 6). With the aid of intensive conservative treatment, the carotid artery-associated risk of stroke can be reduced to as little as 1% per year. Critical determination of indications and strict quality criteria are therefore necessary for CEA and carotid artery stenting (CAS). Systematic reviews of controlled trials comparing CEA and CAS show that the procedural risk of stroke is higher for CAS (asymptomatic: 2.6% versus 1.3%; symptomatic: 6.2% versus 3.8%). There are no differences in the long term. CEA is recommended as standard procedure for high-grade asymptomatic and moderate to high-grade symptomatic carotid artery stenoses; CAS may be considered as an alternative. For both procedures, the periprocedural combined rate of stroke or death should not exceed 2% for asymptomatic stenoses or 4% for symptomatic stenoses.

CONCLUSION

Future studies should evaluate even better selection criteria for optimal individualized treatment, whether conservative, surgical, or endovascular.

Early and Midterm Outcomes of Open and Endovascular Revascularization of Chronic Mesenteric Ischemia

Background

Revascularization strategies for chronic mesenteric ischemia (CMI) include open (OR) and endovascular (ER) modalities. The primary objective of this study was to analyze the safety and effectiveness of OR and ER and the impact of clinical and morphological variables on early and midterm outcomes in a consecutive series of CMI patients in a tertiary referral center.

Patients and methods

From 2004 to 2017, all CMI patients treated with OR and ER were retrospectively identified. Patient records, preoperative imaging, as well as peri- and postoperative outcomes were analyzed. Univariable and multivariable analysis was performed to identify clinical or morphological variables affecting reintervention rates within 2 years.

Results

In total, 63 patients (33% male; mean age 71, range 60–76 years) were treated by ER (41 patients) or OR (22 patients) for CMI. Mean follow-up was 26 (10–71) months. 30-day mortality was 0.0% after ER and 4.5% after OR (p = 0.069); 30-day morbidity was 9.8% vs. 31.8%, respectively (p = 0.030). Length of stay was significantly longer after OR (14 vs. 4 days; p < 0.001). Freedom from reintervention rate after 2 years was 82% after OR and 73% after ER (p = 0.14). Overall survival did not differ after 2 years (OR 85% vs. ER 86%; p = 0.35). Multivariable analysis revealed that smoking was associated with higher risk of reintervention (hazard ratio, HR: 4.14; 95% confidence interval, CI 1.11–15.53; p = 0.03). Additionally, a nonsignificant trend of lower reintervention rates after OR was detected (HR 0.23 95% CI 0.05–1.08; p = 0.06).

Conclusion

Due to a lower invasiveness, despite the higher reintervention rate, an “endovascular first” strategy is justified and recommended.

Multispectral optoacoustic tomography of peripheral arterial disease based on muscle hemoglobin gradients-a pilot clinical study

Background

Current imaging assessment of peripheral artery disease (PAD) relies on anatomical cross-sectional visualizations of the affected arteries. Multispectral optoacoustic tomography (MSOT) is a novel molecular imaging technique that provides direct and label-free visualizations of soft tissue perfusion and oxygenation.

Methods

MSOT was prospectively assessed in a pilot trial in healthy volunteers (group n₁=4, mean age 31, 50% male and group n₃=4, mean age 37.3, 75% male) and patients with intermittent claudication (group n₂=4, mean age 72, 75% male, PAD stage IIb). We conducted cuff-induced ischemia (group n₁) and resting state measurements (groups n₂ and n₃) over the calf region. Spatially resolved mapping of oxygenated (HbO₂), deoxygenated (Hb) and total (THb) hemoglobin, as well as oxygen saturation (SO₂), were measured via hand-held hybrid MSOT-Ultrasound based purely on hemoglobin contrast.

Results

Calf measurements in healthy volunteers revealed distinct dynamics for HbO₂, Hb, THb and SO₂ under cuff-induced ischemia. HbO₂, THb and SO₂ levels were significantly impaired in PAD patients compared to healthy volunteers (P<0.05 for all parameters). Revascularization led to significant improvements in HbO₂ of the affected limb.

Conclusions

Clinical MSOT allows for non-invasive, label-free and real-time imaging of muscle oxygenation in health and disease with implications for diagnostics and therapy assessment in PAD.

Absence of Consistent Sex Differences in Outcomes From Symptomatic Carotid Endarterectomy and Stenting Randomized Trials

BACKGROUND AND PURPOSE

CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial) reported a higher periprocedural risk for any stroke, death, or myocardial infarction for women randomized to carotid artery stenting (CAS) compared with women randomized to carotid endarterectomy (CEA). No difference in risk by treatment was detected for women relative to men in the 4-year primary outcome. We aimed to conduct a pooled analysis among symptomatic patients in large randomized trials to provide more precise estimates of sex differences in the CAS-to-CEA risk for any stroke or death during the 120-day periprocedural period and ipsilateral stroke thereafter.

METHODS

Data from the Carotid Stenosis Trialists' Collaboration included outcomes from symptomatic patients in EVA-3S (Endarterectomy Versus Angioplasty in Patients With Symptomatic Severe Carotid Stenosis), SPACE (Stent-Protected Angioplasty Versus Carotid Endarterectomy in Symptomatic Patients), ICSS (International Carotid Stenting Study), and CREST. The primary outcome was any stroke or death within 120 days after randomization and ipsilateral stroke thereafter. Event rates and relative risks were estimated using Poisson regression; effect modification by sex was assessed with a sex-by-treatment-by-trial interaction term, with significant interaction defined a priori as P≤0.10.

RESULTS

Over a median 2.7 years of follow-up, 433 outcomes occurred in 3317 men and 1437 women. The CAS-to-CEA relative risk of the primary outcome was significantly lower for women compared with men in 1 trial, nominally lower in another, and nominally higher in the other two. The sex-by-treatment-by-trial interaction term was significant (P=0.065), indicating heterogeneity among trials. Contributors to this heterogeneity are primarily differences in periprocedural period. When the trials are nevertheless pooled, there were no significant sex differences in risk in any follow-up period.

CONCLUSIONS

There were significant differences between trials in the magnitude of sex differences in treatment effect (CAS-to-CEA relative risk), indicating pooling data from these trials to estimate sex differences might not be valid. Whether sex is acting as an effect modifier of the CAS-to-CEA treatment effect in symptomatic patients remains uncertain. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00190398 (EVA-3S) and NCT00004732 (CREST). URL: https://www.isrctn.com; Unique identifier: ISRCTN57874028 (SPACE) and ISRCTN25337470 (ICSS).

The TAXINOMISIS Project: A multidisciplinary approach for the development of a new risk stratification model for patients with asymptomatic carotid artery stenosis

INTRODUCTION

Asymptomatic carotid artery stenosis (ACAS) may cause future stroke and therefore patients with ACAS require best medical treatment. Patients at high risk for stroke may opt for additional revascularization (either surgery or stenting) but the future stroke risk should outweigh the risk for peri/post-operative stroke/death. Current risk stratification for patients with ACAS is largely based on outdated randomized-controlled trials that lack the integration of improved medical therapies and risk factor control. Furthermore, recent circulating and imaging biomarkers for stroke have never been included in a risk stratification model. The TAXINOMISIS Project aims to develop a new risk stratification model for cerebrovascular complications in patients with ACAS and this will be tested through a prospective observational multicentre clinical trial performed in six major European vascular surgery centres.

METHODS AND ANALYSIS

The risk stratification model will compromise clinical, circulating, plaque and imaging biomarkers. The prospective multicentre observational study will include 300 patients with 50%-99% ACAS. The primary endpoint is the three-year incidence of cerebrovascular complications. Biomarkers will be retrieved from plasma samples, brain MRI, carotid MRA and duplex ultrasound. The TAXINOMISIS Project will serve as a platform for the development of new computer tools that assess plaque progression based on radiology images and a lab-on-chip with genetic variants that could predict medication response in individual patients.

CONCLUSION

Results from the TAXINOMISIS study could potentially improve future risk stratification in patients with ACAS to assist personalized evidence-based treatment decision-making.

A sparse deep learning approach for automatic segmentation of human vasculature in multispectral optoacoustic tomography

Multispectral Optoacoustic Tomography (MSOT) resolves oxy- (HbO2) and deoxy-hemoglobin (Hb) to perform vascular imaging. MSOT suffers from gradual signal attenuation with depth due to light-tissue interactions: an effect that hinders the precise manual segmentation of vessels. Furthermore, vascular assessment requires functional tests, which last several minutes and result in recording thousands of images. Here, we introduce a deep learning approach with a sparse-UNET (S-UNET) for automatic vascular segmentation in MSOT images to avoid the rigorous and time-consuming manual segmentation. We evaluated the S-UNET on a test-set of 33 images, achieving a median DICE score of 0.88. Apart from high segmentation performance, our method based its decision on two wavelengths with physical meaning for the task-at-hand: 850 nm (peak absorption of oxy-hemoglobin) and 810 nm (isosbestic point of oxy-and deoxy-hemoglobin). Thus, our approach achieves precise data-driven vascular segmentation for automated vascular assessment and may boost MSOT further towards its clinical translation.

Designed CXCR4 mimic acts as a soluble chemokine receptor that blocks atherogenic inflammation by agonist-specific targeting

Targeting a specific chemokine/receptor axis in atherosclerosis remains challenging. Soluble receptor-based strategies are not established for chemokine receptors due to their discontinuous architecture. Macrophage migration-inhibitory factor (MIF) is an atypical chemokine that promotes atherosclerosis through CXC-motif chemokine receptor-4 (CXCR4). However, CXCR4/CXCL12 interactions also mediate atheroprotection. Here, we show that constrained 31-residue-peptides ('msR4Ms') designed to mimic the CXCR4-binding site to MIF, selectively bind MIF with nanomolar affinity and block MIF/CXCR4 without affecting CXCL12/CXCR4. We identify msR4M-L1, which blocks MIF- but not CXCL12-elicited CXCR4 vascular cell activities. Its potency compares well with established MIF inhibitors, whereas msR4M-L1 does not interfere with cardioprotective MIF/CD74 signaling. In vivo-administered msR4M-L1 enriches in atherosclerotic plaques, blocks arterial leukocyte adhesion, and inhibits atherosclerosis and inflammation in hyperlipidemic Apoe-/- mice in vivo. Finally, msR4M-L1 binds to MIF in plaques from human carotid-endarterectomy specimens. Together, we establish an engineered GPCR-ectodomain-based mimicry principle that differentiates between disease-exacerbating and -protective pathways and chemokine-selectively interferes with atherosclerosis.

Biomechanical rupture risk assessment of abdominal aortic aneurysms using clinical data: A patient-specific, probabilistic framework and comparative case-control study

We present a data-informed, highly personalized, probabilistic approach for the quantification of abdominal aortic aneurysm (AAA) rupture risk. Our novel framework builds upon a comprehensive database of tensile test results that were carried out on 305 AAA tissue samples from 139 patients, as well as corresponding non-invasively and clinically accessible patient-specific data. Based on this, a multivariate regression model is created to obtain a probabilistic description of personalized vessel wall properties associated with a prospective AAA patient. We formulate a probabilistic rupture risk index that consistently incorporates the available statistical information and generalizes existing approaches. For the efficient evaluation of this index, a flexible Kriging-based surrogate model with an active training process is proposed. In a case-control study, the methodology is applied on a total of 36 retrospective, diameter matched asymptomatic (group 1, n = 18) and known symptomatic/ruptured (group 2, n = 18) cohort of AAA patients. Finally, we show its efficacy to discriminate between the two groups and demonstrate competitive performance in comparison to existing deterministic and probabilistic biomechanical indices.

Cholesterol, carotid artery disease and stroke: what the vascular specialist needs to know

Hypercholesterolemia is a risk factor for carotid artery stenosis and stroke. Statins are the main drugs for the management of hypercholesterolemia and they are strongly recommended by international guidelines for the management of vascular patients. The present review will focus on the associations between cholesterol, carotid artery stenosis and stroke and will cover several topics, including the conservative and perioperative/periprocedural management of carotid patients, the effect of statins on contrast-induced nephropathy developing after endovascular carotid interventions, the role of statin loading prior to endovascular procedures, as well as the indirect beneficial effects of statin treatment on renal function. It will also discuss the topics of statin intolerance and alternative cholesterol-lowering options for statin-intolerant vascular patients. Cholesterol levels play a prognostic role in carotid patients with regards to both short- and long-term stroke and mortality rates. Physicians should keep in mind the pivotal role of cholesterol levels in determining cardiovascular outcomes and the pleiotropic beneficial effects associated with statin use and should not miss the opportunity for cardiovascular risk reduction with aggressive statin treatment.

Lack of durability after transarterial ethylene-vinyl alcohol copolymer-embolization of type II endoleak following endovascular abdominal aortic aneurysm repair

Background: Type II endoleak (T2EL) after endovascular aortic repair is associated with AAA sac enlargements in up to 25%, reduction of attachment zones and rarely with aortic rupture. Indications for therapy and efficacy of interventions of T2EL are not clearly established. Transarterial embolization with application of ethylene-vinyl alcohol copolymer has been described with varying outcomes. Aim of this study is to evaluate durability of Onyx^TM embolization (OE) in T2EL in a consecutive series at a single tertiary vascular center. Patients and methods: Demographic data, technical success, pre- and postoperative aneurysm growth, morbidity, mortality and reintervention rates during hospital stay as well as in follow up were recorded in patients treated with OE for T2EL between 01/2015 and 12/2017. The primary endpoint was defined as persistence or reoccurrence of T2EL (durability of OE). Results: In total 15 patients (78 ± 6 years, 13 men) were treated with OE because of sac enlargement (average growth of 12 ± 8%, n = 12), persistent bleeding after AAA rupture (n = 2) or persistent T2EL with stable but large aneurysm diameter (n = 1). Mean length of stay was 8 ± 11 days. Technical success was 93.3% (n = 14). Inhospital-morbidity was 26.7%, in-hospital- and 1-year-mortality rate were 6.6% (n = 1) and 20.0% (n = 3). T2EL persisted in 20.0% (n = 3) despite of OE. Re-EL-II occurred after 40 (30-114) days in 33.3% (n = 5). Reintervention rate was 13.3% (n = 2, at day 48 and 319). Altogether clinical success with stable aneurysm diameter was achieved in 80.0% (n = 12), but durable elimination of EL was only achieved in 46.7% of patients (n = 7). Conclusions: OE is technically possible in more than 90% of patients but might be associated with severe complications. Durability of this treatment is low, since T2EL persist or reoccur in more than 50% of all patients. OE of T2EL should be reserved for few selected cases.

The Effects of Minimum Caseload Requirements on Management and Outcome in Abdominal Aortic Aneurysm Repair

BACKGROUND

The German quality assurance guideline on abdominal aortic aneurysm (AAA) was implemented by the Joint Federal Committee (Gemeinsamer Bundesausschuss, G-BA) in 2008. The aims of this study were to verify the association between hospital case volume and outcome and to assess the hypothetical effect of minimum caseload requirements.

METHODS

The German diagnosis-related groups statistics for the years 2012 to 2016 were scrutinized for AAA (ICD-10 GM I71.3/4) with procedure codes for endo - vascular or open surgical treatment. The primary endpoint was in-hospital mortality. Logistic regression models were used for risk adjustment, and odds ratios (OR) were calculated as a function of the annual hospital-level case volume of AAA. In a hypo - thetical approach, the linear distances for various minimum caseloads (MC) were evaluated to assess accessibility.

RESULTS

The mortality of intact AAA (iAAA) was 2.7% (men [M] 2.4%, women [W] 4.2%); ruptured AAA (rAAA), 36.9% (M 36.9%, F 37.5%). An inverse relationship between annual hospital case volume of AAA and mortality was confirmed (iAAA/rAAA: from 3.9%/51% [<10 cases/year] through 3.3%/37% [30-39 cases/year] to 1.9%/28% [≥ 75 cases/year]). For a reference category of 30 AAA procedures/year, the following significant OR were found: 10 AAA cases/year, OR 1.21 (95% confidence interval [1.20; 1.21]); 20 cases, OR 1.09 [1.09; 1.09]; 50 cases, OR 0.89 [0.89; 0.89]; 75 cases, OR 0.82 [0.82; 0.82]. In a hypothetical centralization scenario with assumed MC of 30/year, 86% of the population would have to travel less than 100 km to the nearest hospital; with an MC of 40, this would apply to only 50% (without redistribution effects).

CONCLUSION

In the observed period, a significant correlation was confirmed between high annual case volume and low in-hospital mortality. A minimum caseload requirement of 30 AAA operations/year seems reasonable in view of the accessibility of hospitals. Cite this.

Involvement of Myeloid Cells and Noncoding RNA in Abdominal Aortic Aneurysm Disease

Significance: Abdominal aortic aneurysm (AAA) is a potentially fatal condition, featuring the possibility of high-mortality rupture. To date, prophylactic surgery by means of open surgical repair or endovascular aortic repair at specific thresholds is considered standard therapy. Both surgical options hold different risk profiles of short- and long-term morbidity and mortality. Targeting early stages of AAA development to decelerate disease progression is desirable. Recent Advances: Understanding the pathomechanisms that initiate formation, maintain growth, and promote rupture of AAA is crucial to developing new medical therapeutic options. Inflammatory cells, in particular macrophages, have been investigated for their contribution to AAA disease for decades, whereas evidence on lymphocytes, mast cells, and neutrophils is sparse. Recently, there has been increasing interest in noncoding RNAs (ncRNAs) and their involvement in disease development, including AAA. Critical Issues: The current evidence on myeloid cells and ncRNAs in AAA largely originates from small animal models, making clinical extrapolation difficult. Although it is feasible to collect surgical human AAA samples, these tissues reflect end-stage disease, preventing examination of critical mechanisms behind early AAA formation. Future Directions: Gaining more insight into how myeloid cells and ncRNAs contribute to AAA disease, particularly in early stages, might suggest nonsurgical AAA treatment options. The utilization of large animal models might be helpful in this context to help bridge translational results to humans.

Time of day does not influence outcomes in acute type A aortic dissection: Results from the IRAD

BACKGROUND

Type A acute aortic dissection (TAAAD) represents a surgical emergency requiring intervention regardless of time of day. Whether such a "evening effect" exists regarding outcomes for TAAAD has not been previously studied using a large registry data.

METHODS

Patients with TAAAD were identified from the International Registry of Acute Aortic Dissections (1996-2019). Outcomes were compared between patients undergoing operative repair during the daytime (D), defined as 8 am-5 pm, versus the evening (N), defined as 5 pm-8 am.

RESULTS

Four thousand one-hundrd and ninety-seven surgically treated patients with TAAAD were identified, with 1824 patients undergoing daytime surgery (43.5%) and 2373 patients undergoing evening surgery (56.5%). Daytime patients were more likely to have undergone prior cardiac surgery (13.2% vs. 9.5%; p < .001) and have had a prior aortic dissection (4.8% vs. 3.4%; p = .04). Evening patients were more likely to have been transferred from a referring hospital (70.8% vs. 75.0%; p = .003). Daytime patients were more likely to undergo aortic valve sparing root procedures (23.3% vs. 19.2%; p = .035); however, total arch replacement was performed with equal frequency (19.4% vs. 18.8%; p = .751). In-hospital mortality (D: 17.3% vs. N. 16.2%; p = .325) was similar between both groups. Subgroup analysis examining the effect of weekend presentation revealed no significant mortality difference.

CONCLUSIONS

A majority of TAAAD patients underwent surgical repair at night. There were higher rates of postoperative tamponade in evening patients; however, mortality was similar. The expertise of cardiac-dedicated operative and critical care teams regardless of time of day as well as training paradigms may explain similar mortality outcomes in this high risk population.

Early Outcomes in the ROADSTER 2 Study of Transcarotid Artery Revascularization in Patients With Significant Carotid Artery Disease

Background and Purpose:

Transcarotid artery revascularization (TCAR) is comprised of carotid artery stent placement with cerebral protection via proximal carotid artery clamping and reversal of cerebral arterial flow. The aim of the present study was to evaluate the safety and efficacy of TCAR performed by a broad group of physicians with variable TCAR experience.

Methods:

The ROADSTER 2 study is a prospective, open label, single arm, multicenter, postapproval registry for patients undergoing TCAR. Patients considered at high risk for complications from carotid endarterectomy with symptomatic stenosis ≥50% or asymptomatic stenosis ≥80% were included. The primary end point was procedural success, which encompassed technical success plus the absence of stroke, myocardial infarction, or death within the 30-day postoperative period. Secondary end points included technical success and individual/composite rates of stroke, death, and myocardial infarction (MI). All patients underwent independent neurological assessments before the procedure, within 24 hours, and at 30 days after TCAR. An independent clinical events committee adjudicated all major adverse events.

Results:

Between 2015 and 2019, 692 patients (Intent to Treat Population) were enrolled at 43 sites. Sixty cases had major protocol violations, leaving 632 patients adhering to the Food and Drug Administration-approved protocol (per-protocol population). The majority (81.2%) of operators were TCAR naïve before study initiation. Patients underwent TCAR for neurological symptoms in 26% of cases, and all patients had high-risk factors for carotid endarterectomy (anatomic-related 44%; physiological 32%; both 24%). Technical success occurred in 99.7% of all cases. The primary end point of procedural success rate in the Intent to Treat population was 96.5% (per-protocol 97.9%). The early postoperative outcomes in the Intent to Treat population included stroke in 13 patients (1.9%), death in 3 patients (0.4%), and MI in 6 patients (0.9%). The composite 30-day stroke/death rate was 2.3%, and stroke/death/MI rate was 3.2%. In the per-protocol population, there were strokes in 4 patients (0.6%), death in one patient (0.2%), and MI in 6 patients (0.9%) leading to a composite 30-day stroke/death rate of 0.8% and stroke/death/MI rate of 1.7%.

Conclusions:

TCAR results in excellent early outcomes with high technical success combined with low rates of postprocedure stroke and death. These results were achieved by a majority of operators new to this technology at the start of the trial. Adherence to the study protocol and peri-procedural antiplatelet therapy optimizes outcomes. Longer-term follow-up data are needed to confirm these early outcomes.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02536378.

Hospital Incidence and In-Hospital Mortality of Surgically and Interventionally Treated Aortic Dissections: Secondary Data Analysis of the Nationwide German Diagnosis-Related Group Statistics From 2006 to 2014

Background

Population‐based data about the incidence and mortality of patients with aortic dissections (ADs) are sparse. Therefore, the hospital incidence and in‐hospital mortality of patients undergoing open or endovascular surgery for type A ADs (TAADs) and type B ADs (TBADs) in Germany were analyzed on a nationwide basis between 2006 and 2014.

Methods and Results

A secondary data analysis of the nationwide diagnosis‐related group statistics, compiled by the German Federal Statistical Office, was performed for patients who were surgically/interventionally treated for AD (International Classification of Diseases, Tenth Revision, German Modification [ICD‐10‐GM] codes I71.00‐I71.07; n=20 533). By using specific procedure codes, a distinction between TAAD (n=14 911/72.6%) and TBAD (n=5622/27.4%) could be made. The standardized hospital incidence of surgically/interventionally treated AD was 2.7/100 000 per year, comprising 2.0/100 000 per year for TAAD and 0.7/100 000 per year for TBAD. The in‐hospital mortality of TAAD was 19.5%; and of TBAD, 9.3%. Both the incidence and in‐hospital mortality increased over the 9‐year period. The share of endovascularly treated TBAD increased steadily during the same time interval. A multilevel multivariable analysis revealed that, for TAAD, age and comorbidity were significantly associated with a higher mortality risk.

The latter was also true for TBAD. Sex was not significantly associated with mortality. A significant association between higher annual center volume and mortality was found for TAAD, but not for TBAD.

Conclusions

This is the first report on hospital incidence and mortality for surgically/interventionally treated AD on a nationwide basis. Overall, in Germany, hospital incidence and mortality of TAAD and TBAD increased over time. In addition, TAAD is performed more safely in high‐volume centers.

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Screening cardiovascular patients for aortic aneurysms (SCAN) - high prevalence of abdominal aortic aneurysms in coronary heart disease patients requiring intervention

Background: Since the prevalence of abdominal aortic aneurysms (AAA) in Europe has declined to about 2.5%, general screening programs of elderly men are being called into question. On the other hand, other vascular diseases (e.g. coronary heart disease, CHD) are associated with a higher prevalence of AAA. This might have an impact on future targeted AAA screening programs. This study aimed to reevaluate the current prevalence of AAA in male patients with CHD, in order to assess whether CHD patients should be offered a targeted AAA ultrasound screening program. Patients and methods: The SCAN (Screening Cardiovascular Patients for Aortic Aneurysms) study prospectively evaluated the AAA prevalence in 1000 consecutive male CHD patients (70.1 ± 11.2 years) requiring any coronary intervention at an university hospital. All patients received transverse and longitudinal ultrasound scans of the abdominal aorta. Aortic diameter was assessed using the outer-to-outer measurement-technique. Primary endpoint was the prevalence of AAA. Secondary outcomes included stratification in 1-, 2-, or 3-vessel CHD. Results: AAA was detected in 85 patients (median diameter 38 mm, range 30-80 mm), corresponding to an overall prevalence of 8.5%. AAA prevalence was significantly associated with CHD severity: 5.6% in 1-vessel, 7.1% in 2-vessel, and 10.8% in 3-vessel CHD (P = 0.037). The multivariable analysis showed, that age per 10 years increase (OR 1.5, 95% CI 1.2-1.9, P = 0.001) and hyperlipidemia (OR 2.2, 95% CI 1.3-3.8, P = 0.003) were significantly associated with an AAA. The likelihood to be diagnosed with an AAA was significantly lower in non-smokers (OR 0.24, 95% CI, P < 0.001). Conclusions: This study confirms that CHD requiring any type of coronary intervention is strongly associated with AAA in male patients. AAA prevalence increases with CHD severity. Since the AAA prevalence is still significantly higher than in the general population, targeted ultrasound screening should be considered for all CHD patients.

Multispectral optoacoustic tomography of muscle perfusion and oxygenation under arterial and venous occlusion: A human pilot study

Perfusion and oxygenation are critical parameters of muscle metabolism in health and disease. They have been both the target of many studies, in particular using near-infrared spectroscopy (NIRS). However, difficulties with quantifying NIRS signals have limited a wide dissemination of the method to the clinics. Our aim was to investigate whether clinical multispectral optoacoustic tomography (MSOT) could enable the label-free imaging of muscle perfusion and oxygenation under clinically relevant challenges: the arterial and venous occlusion. We employed a hybrid clinical MSOT/ultrasound system equipped with a hand-held scanning probe to visualize hemodynamic and oxygenation changes in skeletal muscle under arterial and venous occlusions. Four (N = 4) healthy volunteers were scanned over the forearm for both 3-minute occlusion challenges. MSOT-recorded pathophysiologically expected results during tests of disturbed blood flow with high resolution and without the need for contrast agents. During arterial occlusion, MSOT-extracted Hb-values showed an increase, while HbO₂ - and total blood volume (TBV)-values remained roughly steady, followed by a discrete increase during the hyperemic period after cuff deflation. During venous occlusion, results showed a clear increase in intramuscular HbO₂ , Hb and TBV within the segmented muscle area. MSOT was found to be capable of label-free non-invasive imaging of muscle hemodynamics and oxygenation under arterial and venous occlusion. We introduce herein MSOT as a novel modality for the assessment of vascular disorders characterized by disturbed blood flow, such as acute limb ischemia and venous thrombosis.