Radiation therapy for cancer is potentially associated with reduced growth of concomitant abdominal aortic aneurysm

PURPOSE

Co-prevalence of abdominal aortic aneurysm (AAA) and cancer poses a unique challenge in medical care since both diseases and their respective therapies might interact. Recently, reduced AAA growth rates were observed in cancer patients that received radiation therapy (RT). The purpose of this study was to perform a fine-grained analysis of the effects of RT on AAA growth with respect to direct (infield) and out-of-field (outfield) radiation exposure, and radiation dose-dependency.

METHODS

A retrospective single-center analysis identified patients with AAA, cancer, and RT. Clinical data, radiation plans, and aneurysm diameters were analyzed. The total dose of radiation to each aneurysm was computed. AAA growth under infield and outfield exposure was compared to patients with AAA and cancer that did not receive RT (no-RT control) and to an external noncancer AAA reference cohort.

RESULTS

Between 2003 and 2020, a total of 38 AAA patients who had received well-documented RT for their malignancy were identified. AAA growth was considerably reduced for infield patients (n = 18) compared to outfield patients (n = 20), albeit not significantly (0.8 ± 1.0 vs. 1.3 ± 1.6 mm/year, p = 0.28). Overall, annual AAA growth in RT patients was lower compared to no-RT control patients (1.1 ± 1.5 vs. 1.8 ± 2.2 mm/year, p = 0.06) and significantly reduced compared to the reference cohort (1.1 ± 1.5 vs. 2.7 ± 2.1 mm/year, p < 0.001). The pattern of AAA growth reduction due to RT was corroborated in linear regression analyses correcting for initial AAA diameter. A further investigation with respect to dose-dependency of radiation effects on AAA growth, however, revealed no apparent association.

CONCLUSION

In this study, both infield and outfield radiation exposure were associated with reduced AAA growth. This finding warrants further investigation, both in a larger scale clinical cohort and on a molecular level.

Intraoperative Completion Studies and their Associations with Carotid Endarterectomy Outcomes

OBJECTIVE

This study aimed at assessing outcomes after carotid endarterectomy (CEA) in dependence of center policy with respect to imaging intraoperative completion study (ICS i ) usage.

SUMMARY BACKGROUND DATA

Although randomized controlled studies are missing, a beneficial effect was shown for ICS i techniques (i.e., angiography and intraoperative duplex ultrasound) after CEA.

METHODS

This secondary data analysis is based on the German statutory quality assurance database. Research was funded by Germany's Federal Joint Committee Innovation Fund (G-BA Innovationsfonds, 01VSF19016 ISAR-IQ). According to their ICS i policy, hospitals were categorized as routine ICSi (>90%), selective ICSi (10-90%), or sporadic ICSi (<10%) centers . Primary study outcome was in-hospital stroke or death. Multivariable regression analyses were performed.

RESULTS

Between 2012 and 2016, a total of 119,800 patients underwent CEA. In-hospital stroke or death rates were lower in routine ICSicenters (1.7%) compared to selective (2.1%) and sporadic ICSicenters (2.0%). The multivariable regression analysis showed, that in routine ICSicenters , ICS i use was associated with lower rates of stroke or death (aOR 0.64; 95% CI 0.44-0.93). In selective ICSicenters , ICS i was not associated with the occurrence of either of the assessed outcomes. In sporadic ICSicenters , ICS i was associated with higher rates of stroke or death (aOR 1.91; 95% CI 1.26-2.91).

CONCLUSIONS

Lowest in-hospital stroke or death rates are achieved in r outine ICSicenters . While ICS i is associated with a lower perioperative risk in r outine ICSicenters , it might act as a surrogate marker for worse outcomes due to intraoperative irregularities in sporadic ICSicenters . Routine use of ICS i is advisable.

Macro- and microvascular contributions to cerebral structural alterations in patients with asymptomatic carotid artery stenosis

Atherosclerosis can underly internal carotid artery stenosis (ICAS), a major risk factor for ischemic stroke, as well as small vessel disease (SVD). This study aimed to investigate hemodynamics and structural alterations associated with SVD in ICAS patients. 28 patients with unilateral asymptomatic ICAS and 30 age-matched controls underwent structural (T1-/T2-weighted and diffusion tensor imaging [DTI]) and hemodynamic (pseudo-continuous arterial spin labeling and dynamic susceptibility contrast) magnetic resonance imaging. SVD-related alterations were assessed using free water (FW), FW-corrected DTI, and peak-width of skeletonized mean diffusivity (PSMD). Furthermore, cortical thickness, cerebral blood flow (CBF), and capillary transit time heterogeneity (CTH) were analyzed. Ipsilateral to the stenosis, cortical thickness was significantly decreased in the posterior dorsal cingulate cortex (p = 0.024) and temporal pole (p = 0.028). ICAS patients exhibited elevated PSMD (p = 0.005), FW (p < 0.001), and contralateral alterations in FW-corrected DTI metrics. We found significantly lateralized CBF (p = 0.011) and a tendency for lateralized CTH (p = 0.067) in the white matter (WM) related to ICAS. Elevated PSMD and FW may indicate a link between SVD and WM changes. Contralateral alterations were seen in FW-corrected DTI, whereas hemodynamic and cortical changes were mainly ipsilateral, suggesting SVD might influence global brain changes concurrent with ICAS-related hemodynamic alterations.

Utilization of an Artery-on-a-Chip to Unravel Novel Regulators and Therapeutic Targets in Vascular Diseases

In this study, organ-on-chip technology is used to develop an in vitro model of medium-to-large size arteries, the artery-on-a-chip (AoC), with the objective to recapitulate the structure of the arterial wall and the relevant hemodynamic forces affecting luminal cells. AoCs exposed either to in vivo-like shear stress values or kept in static conditions are assessed to generate a panel of novel genes modulated by shear stress. Considering the crucial role played by shear stress alterations in carotid arteries affected by atherosclerosis (CAD) and abdominal aortic aneurysms (AAA) disease development/progression, a patient cohort of hemodynamically relevant specimens is utilized, consisting of diseased and non-diseased (internal control) vessel regions from the same patient. Genes activated by shear stress follow the same expression pattern in non-diseased segments of human vessels. Single cell RNA sequencing (scRNA-seq) enables to discriminate the unique cell subpopulations between non-diseased and diseased vessel portions, revealing an enrichment of flow activated genes in structural cells originating from non-diseased specimens. Furthermore, the AoC served as a platform for drug-testing. It reproduced the effects of a therapeutic agent (lenvatinib) previously used in preclinical AAA studies, therefore extending the understanding of its therapeutic effect through a multicellular structure.

Goal-directed Perioperative Albumin Substitution Versus Standard of Care to Reduce Postoperative Complications: A Randomized Clinical Trial (SuperAdd Trial)

OBJECTIVE

To investigate whether goal-directed albumin substitution during surgery and postanesthesia care to maintain a serum albumin concentration >30 g/L can reduce postoperative complications.

BACKGROUND

Hypoalbuminemia is associated with numerous postoperative complications. Since albumin has important physiological functions, substitution of patients with hypoalbuminemia is worth considering.

METHODS

We conducted a single-center, randomized, controlled, outcome assessor-blinded clinical trial in adult patients, American Society of Anesthesiologists physical status classification 3 to 4 or undergoing high-risk surgery. Patients, whose serum albumin concentration dropped <30 g/L were randomly assigned to goal-directed albumin substitution maintaining serum concentration >30 g/L or to standard care until discharge from the postanesthesia intermediate care unit. Standard of care allowed albumin substitution in hemodynamic instable patients with serum concentration <20 g/L, only. Primary outcome was the incidence of postoperative complications ≥2 according to the Clavien-Dindo Classification in at least 1 of 9 domains (pulmonary, infectious, cardiovascular, neurological, renal, gastrointestinal, wound, pain, and hematological) until postoperative day 15.

RESULTS

Of 2509 included patients, 600 (23.9%) developed serum albumin concentrations <30 g/L. Human albumin 60 g (40-80 g) was substituted to 299 (99.7%) patients in the intervention group and to 54 (18.0%) in the standard care group. At least 1 postoperative complication classified as Clavien-Dindo Classification ≥2 occurred in 254 of 300 patients (84.7%) in the intervention group and in 262 of 300 (87.3%) in the standard treatment group (risk difference -2.7%, 95% CI, -8.3% to 2.9%).

CONCLUSION

Maintaining serum albumin concentration of >30 g/L perioperatively cannot generally be recommended in high-risk noncardiac surgery patients.

An international, multispecialty, expert-based Delphi Consensus document on controversial issues in the management of patients with asymptomatic and symptomatic carotid stenosis

OBJECTIVE

Despite the publication of various national/international guidelines, several questions concerning the management of patients with asymptomatic (AsxCS) and symptomatic (SxCS) carotid stenosis remain unanswered. The aim of this international, multi-specialty, expert-based Delphi Consensus document was to address these issues to help clinicians make decisions when guidelines are unclear.

METHODS

Fourteen controversial topics were identified. A three-round Delphi Consensus process was performed including 61 experts. The aim of Round 1 was to investigate the differing views and opinions regarding these unresolved topics. In Round 2, clarifications were asked from each participant. In Round 3, the questionnaire was resent to all participants for their final vote. Consensus was reached when ≥75% of experts agreed on a specific response.

RESULTS

Most experts agreed that: (1) the current periprocedural/in-hospital stroke/death thresholds for performing a carotid intervention should be lowered from 6% to 4% in patients with SxCS and from 3% to 2% in patients with AsxCS; (2) the time threshold for a patient being considered "recently symptomatic" should be reduced from the current definition of "6 months" to 3 months or less; (3) 80% to 99% AsxCS carries a higher risk of stroke compared with 60% to 79% AsxCS; (4) factors beyond the grade of stenosis and symptoms should be added to the indications for revascularization in AsxCS patients (eg, plaque features of vulnerability and silent infarctions on brain computed tomography scans); and (5) shunting should be used selectively, rather than always or never. Consensus could not be reached on the remaining topics due to conflicting, inadequate, or controversial evidence.

CONCLUSIONS

The present international, multi-specialty expert-based Delphi Consensus document attempted to provide responses to several unanswered/unresolved issues. However, consensus could not be achieved on some topics, highlighting areas requiring future research.

A Modern Series of Secondary Aortoenteric Fistula - A 19-Year Experience

OBJECTIVES

Secondary aortoenteric fistula is a rare and life-threatening condition. Clear evidence on the ideal therapeutic approach is largely missing. This study aims to analyze symptoms, etiology, risk factors, and outcomes based on procedural details.

PATIENTS AND METHODS

All patients with secondary aortoenteric fistula admitted between 2003 and 2021 were included. Patient characteristics, surgical procedure details, and postoperative outcomes were analyzed. Outcomes were stratified and compared according to the urgency of operation and the procedure performed. Descriptive statistics were used. The primary endpoint was in-hospital mortality.

RESULTS

A total of twentytwo patients (68% male, median age 70 years) were identified. Main symptoms were gastrointestinal bleeding, pain, and fever. From the twentytwo patients ten patients required emergency surgery and ten urgent surgery. Emergency patients were older on average (74 vs 63 years, P = .015) and had a higher risk of postoperative respiratory complications (80% vs 10%, P = .005). Primary open surgery with direct replacement of the aorta or an extra-anatomic bypass with an additional direct suture or resection of the involved bowel was performed in sixteen patients. In four patients underwent endovascular bridging treatment with the definitive approach as a second step. Other two patients died without operation (1x refusal; 1x palliative cancer history). In-hospital mortality was 27%, respectively. Compared to patients undergoing urgent surgery, those treated emergently showed significantly higher in-hospital (50% vs 0%, P = .0033) mortalities.

CONCLUSION

Despite rapid diagnosis and treatment, secondary aortoenteric fistula remains a life-threatening condition with 27% in-hospital mortality, significantly increased upon emergency presentation.

Aortic Vascular Graft and Endograft Infection-Patient Outcome Cannot Be Determined Based on Pre-Operative Characteristics

Vascular graft/endograft infection (VGEI) is a serious complication after aortic surgery. This study investigates VGEI and patient characteristics, PET/CT quantification before surgical or conservative management of VGEI and post-intervention outcomes in order to identify patients who might benefit from such a procedure. PET standard uptake values (SUV) were quantitatively assessed and compared to a non-VGEI cohort. The primary endpoints were in-hospital mortality and aortic reintervention-free survival at six months. Ninety-three patients (75% male, 65 ± 10 years, 82% operated) were included. The initial operation was mainly for aneurysm (67.7%: 31% EVAR, 12% TEVAR, 57% open aortic repair). Thirty-two patients presented with fistulae. PET SUVTLR (target-to-liver ratio) showed 94% sensitivity and 89% specificity. Replacement included silver-coated Dacron (21.3%), pericardium (61.3%) and femoral vein (17.3%), yet the material did not influence the overall survival (p = 0.745). In-hospital mortality did not differ between operative and conservative treatment (19.7% vs. 17.6%, p = 0.84). At six months, 50% of the operated cohort survived without aortic reintervention. Short- and midterm morbidity and mortality remained high after aortic graft removal. Neither preoperative characteristics nor the material used for reconstruction influenced the overall survival, and, with limitations, both the in-hospital and midterm survival were similar between the surgically and conservatively managed patients.

Endovascular aortic repair with sac embolization for the prevention of type II endoleaks (the EVAR-SE study): study protocol for a randomized controlled multicentre study in Germany

BACKGROUND

Beyond a certain threshold diameter, abdominal aortic aneurysms (AAA) are to be treated by open surgical or endovascular aortic aneurysm repair (EVAR). In a quarter of patients who undergo EVAR, inversion of blood flow in the inferior mesenteric artery or lumbar arteries may lead to type II endoleak (T2EL), which is associated with complications (e.g. AAA growth, secondary type I endoleak, rupture). As secondary interventions to treat T2EL often fail and may be highly invasive, prevention of T2EL is desirable. The present study aims to assess the efficacy of sac embolization (SE) with metal coils during EVAR to prevent T2EL in patients at high risk.

METHODS

Over a 24-month recruitment period, a total of 100 patients undergoing EVAR in four vascular centres (i.e. Klinikum rechts der Isar of the Technical University of Munich, University Hospital Augsburg, University Hospital Dresden, St. Joseph's Hospital Wiesbaden) are to be included in the present study. Patients at high risk for T2EL (i.e. ≥ 5 efferent vessels covered by endograft or aneurysmal thrombus volume <40%) are randomized to one group receiving standard EVAR and another group receiving EVAR with SE. Follow-up assessments postoperatively, after 30 days, and 6 months involve contrast-enhanced ultrasound scans (CEUS) and after 12 months an additional computed tomography angiography (CTA) scan. The presence of T2EL detected by CEUS or CTA after 12 months is the primary endpoint. Secondary endpoints comprise quality of life (quantified by the SF-36 questionnaire), reintervention rate, occurrence of type I/III endoleak, aortic rupture, death, alteration of aneurysm volume, or diameter. Standardized evaluation of CTA scans happens through a core lab. The study will be terminated after the final follow-up visit of the ultimate patient.

DISCUSSION

Although preexisting studies repeatedly indicated a beneficial effect of SE on T2EL rates after EVAR, patient relevant outcomes have not been assessed until now. The present study is the first randomized controlled multicentre study to assess the impact of SE on quality of life. Further unique features include employment of easily assessable high-risk criteria, a contemporary follow-up protocol, and approval to use any commercially available coil material. Overcoming limitations of previous studies might help SE to be implemented in daily practice and to enhance patient safety.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05665101. Registered on 23 December 2022.

Neurological event rates and associated risk factors in acute type B aortic dissections treated by thoracic aortic endovascular repair

OBJECTIVES

Thoracic endovascular aortic repair is the method of choice in patients with complicated type B acute aortic dissection. However, thoracic endovascular aortic repair carries a risk of periprocedural neurological events including stroke and spinal cord ischemia. We aimed to look at procedure-related neurological complications within a large cohort of patients with type B acute aortic dissection treated by thoracic endovascular aortic repair.

METHODS

Between 1996 and 2021, the International Registry of Acute Aortic Dissection collected data on 3783 patients with type B acute aortic dissection. For this analysis, 648 patients with type B acute aortic dissection treated by thoracic endovascular aortic repair were included (69.4% male, mean age 62.7 ± 13.4 years). Patients were excluded who presented with a preexisting neurologic deficit or received adjunctive procedures. Demographics, clinical symptoms, and outcomes were analyzed. The primary end point was the periprocedural incidence of neurological events (defined as stroke, spinal cord ischemia, transient neurological deficit, or coma). Predictors for perioperative neurological events and follow-up outcomes were considered as secondary end points.

RESULTS

Periprocedure neurological events were noted in 72 patients (11.1%) and included strokes (n = 29, 4.6%), spinal cord ischemias (n = 21, 3.3%), transient neurological deficits (n = 16, 2.6%), or coma (n = 6, 1.0%). The group with neurological events had a significantly higher in-hospital mortality (20.8% vs 4.3%, P < .001). Patients with neurological events were more likely to be female (40.3% vs 29.3%, P = .077), and aortic rupture was more often cited as an indication for thoracic endovascular aortic repair (38.8% vs 16.5%, P < .001). In patients with neurological events, more stent grafts were used (2 vs 1 stent graft, P = .002). Multivariable logistic regression analysis showed that aortic rupture (odds ratio, 3.12, 95% confidence interval, 1.44-6.78, P = .004) and female sex (odds ratio, 1.984, 95% confidence interval, 1.031-3.817, P = .040) were significantly associated with perioperative neurological events.

CONCLUSIONS

In this highly selected group from dedicated aortic centers, more than 1 in 10 patients with type B acute aortic dissection treated by thoracic endovascular aortic repair had neurological events, in particular women. Further research is needed to identify the causes and presentation of these events after thoracic endovascular aortic repair, especially among women.

Editor's Choice - Temporal fluctuations of hospital incidence and mortality of ruptured abdominal aortic aneurysms in Germany: A secondary data analysis of German hospital episode statistics 2009 - 2018

OBJECTIVE

Abdominal aortic aneurysm rupture (rAAA) is still associated with high mortality. Recent studies have shown higher incidences in autumn and winter, and worse outcomes after rAAA treatment on weekends in some countries. This study aimed to analyse seasonal, weekday, and daytime fluctuations of the hospital incidence, treatment modalities, and outcomes of rAAA, based on the most recent nationwide German real world data.

METHODS

A secondary data analysis of diagnosis related group statistics (2009 - 2018), obtained from the German Federal Statistical Office, was conducted. Cases encoded by a diagnosis of rAAA in conjunction with procedural codes for endovascular aortic repair (EVAR) or open aortic repair were included. Patient and procedural characteristics, comorbidities, and outcomes were analysed for seasonal (spring, summer, autumn, and winter), weekday (Monday - Sunday) and daytime (0:00 - 8:00, 8:00 -16:00, 16:00 -20:00, and 20:00 - 24:00) fluctuations by descriptive statistics and multivariable regression analyses.

RESULTS

Thirteen thousand and seventy patients (85% male, median age 75 years) were treated for rAAA. Endovascular aortic repair was associated with lower mortality (adjusted OR 0.40, 95% CI 0.37 - 0.44). While no significant seasonal fluctuations were found, on a weekday basis lower hospital incidences were found on Mondays (12%) and Sundays (11%) compared with other weekdays (15 - 16%). Similarly, EVAR rates were lower on Mondays and Sundays (25% and 24%, respectively) compared with other weekdays (30 - 33%). Multivariable analyses revealed higher mortality rates on Mondays and Sundays. On a daytime basis, lower EVAR rates and higher mortality rates were found during the 16:00 - 8:00 period.

CONCLUSION

In German hospitals, incidences and EVAR rates to treat rAAA were lowest on Mondays and Sundays. The associated overall mortality rates were highest on the respective days. Further restructuring and centralisation of AAA treatment in Germany could potentially mitigate this weekday effect.

Dermal features derived from optoacoustic tomograms via machine learning correlate microangiopathy phenotypes with diabetes stage

Skin microangiopathy has been associated with diabetes. Here we show that skin-microangiopathy phenotypes in humans can be correlated with diabetes stage via morphophysiological cutaneous features extracted from raster-scan optoacoustic mesoscopy (RSOM) images of skin on the leg. We obtained 199 RSOM images from 115 participants (40 healthy and 75 with diabetes), and used machine learning to segment skin layers and microvasculature to identify clinically explainable features pertaining to different depths and scales of detail that provided the highest predictive power. Features in the dermal layer at the scale of detail of 0.1-1 mm (such as the number of junction-to-junction branches) were highly sensitive to diabetes stage. A 'microangiopathy score' compiling the 32 most-relevant features predicted the presence of diabetes with an area under the receiver operating characteristic curve of 0.84. The analysis of morphophysiological cutaneous features via RSOM may allow for the discovery of diabetes biomarkers in the skin and for the monitoring of diabetes status.

Optoacoustic biomarkers of lipids, hemorrhage and inflammation in carotid atherosclerosis

Imaging plays a critical role in exploring the pathophysiology and enabling the diagnostics and therapy assessment in carotid artery disease. Ultrasonography, computed tomography, magnetic resonance imaging and nuclear medicine techniques have been used to extract of known characteristics of plaque vulnerability, such as inflammation, intraplaque hemorrhage and high lipid content. Despite the plethora of available techniques, there is still a need for new modalities to better characterize the plaque and provide novel biomarkers that might help to detect the vulnerable plaque early enough and before a stroke occurs. Optoacoustics, by providing a multiscale characterization of the morphology and pathophysiology of the plaque could offer such an option. By visualizing endogenous (e.g., hemoglobin, lipids) and exogenous (e.g., injected dyes) chromophores, optoacoustic technologies have shown great capability in imaging lipids, hemoglobin and inflammation in different applications and settings. Herein, we provide an overview of the main optoacoustic systems and scales of detail that enable imaging of carotid plaques in vitro, in small animals and humans. Finally, we discuss the limitations of this novel set of techniques while investigating their potential to enable a deeper understanding of carotid plaque pathophysiology and possibly improve the diagnostics in future patients with carotid artery disease.

ZILVERPASS Study: ZILVER PTX Stent versus Prosthetic Above-the-Knee Bypass Surgery in Femoropopliteal Lesions, 5-year Results

PURPOSE

To report the 60-month safety and effectiveness results of a multicenter, prospective, randomized controlled trial comparing the ZILVER PTX paclitaxel-eluting stent to prosthetic above-the-knee bypass for the treatment of symptomatic TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions.

MATERIALS AND METHODS

Patients were enrolled between October 2013 and July 2017. One of the secondary outcomes was primary patency at 60 months, defined as no evidence of binary restenosis or occlusion within the target lesion or bypass graft based on a duplex ultrasound peak systolic velocity ratio < 2.4 and no clinically-driven target lesion revascularization (TLR) in endovascular cases or reintervention to restore flow in the bypass at 60 months. Survival rates after 5 years were also analyzed.

RESULTS

220 patients (mean age 68.6 ± 10.5 years; 159 men) were included and randomized to ZILVER PTX (n = 113, 51.40%) or BYPASS group (n = 107, 48.60%). The 60-month primary patency rate was 49.3% for the ZILVER PTX group versus 40.7% for the bypass group (p = 0.6915). Freedom from TLR was 63.8% for the ZILVER PTX group versus 52.8% for the bypass group (p = 0.2637). At 5 years, no significant difference in survival rate could be seen between the ZILVER PTX and the bypass group (69.1% vs. 71% respectively, p = 0.5503).

CONCLUSION

Even at 5 years, non-inferior safety and effectiveness results of the ZILVER PTX could be seen. These findings confirmed that the use of ZILVER PTX stents can be considered as a valid alternative for bypass surgery when treating long and complex femoropopliteal lesions.

Opening a window to skin biomarkers for diabetes stage with optoacoustic mesoscopy

Being the largest and most accessible organ of the human body, the skin could offer a window to diabetes-related complications on the microvasculature. However, skin microvasculature is typically assessed by histological analysis, which is not suited for applications to large populations or longitudinal studies. We introduce ultra-wideband raster-scan optoacoustic mesoscopy (RSOM) for precise, non-invasive assessment of diabetes-related changes in the dermal microvasculature and skin micro-anatomy, resolved with unprecedented sensitivity and detail without the need for contrast agents. Providing unique imaging contrast, we explored a possible role for RSOM as an investigational tool in diabetes healthcare and offer the first comprehensive study investigating the relationship between different diabetes complications and microvascular features in vivo. We applied RSOM to scan the pretibial area of 95 participants with diabetes mellitus and 48 age-matched volunteers without diabetes, grouped according to disease complications, and extracted six label-free optoacoustic biomarkers of human skin, including dermal microvasculature density and epidermal parameters, based on a novel image-processing pipeline. We then correlated these biomarkers to disease severity and found statistically significant effects on microvasculature parameters as a function of diabetes complications. We discuss how label-free RSOM biomarkers can lead to a quantitative assessment of the systemic effects of diabetes and its complications, complementing the qualitative assessment allowed by current clinical metrics, possibly leading to a precise scoring system that captures the gradual evolution of the disease.

The circular RNA Ataxia Telangiectasia Mutated regulates oxidative stress in smooth muscle cells in expanding abdominal aortic aneurysms

An abdominal aortic aneurysm (AAA) is a pathological widening of the aortic wall characterized by loss of smooth muscle cells (SMCs), extracellular matrix degradation, and local inflammation. This condition is often asymptomatic until rupture occurs, leading to high morbidity and mortality rates. Diagnosis is mostly accidental and the only currently available treatment option remains surgical intervention. Circular RNAs (circRNAs) represent a novel class of regulatory non-coding RNAs that originate from backsplicing. Their highly stable loop structure, combined with a remarkable enrichment in body fluids, make circRNAs promising disease biomarkers. We investigated the contribution of circRNAs to AAA pathogenesis and their potential application to improve AAA diagnostics. Gene expression analysis revealed the presence of deregulated circular transcripts stemming from AAA-relevant gene loci. Among these, the circRNA to the Ataxia Telangiectasia Mutated gene (cATM) was upregulated in human AAA specimens, in AAA-derived SMCs, and serum samples collected from aneurysm patients. In primary aortic SMCs, cATM increased upon angiotensin II and doxorubicin stimulation, while its silencing triggered apoptosis. Higher cATM levels made AAA-derived SMCs less vulnerable to oxidative stress, compared with control SMCs. These data suggest that cATM contributes to elicit an adaptive oxidative-stress response in SMCs and provides a reliable AAA disease signature.

Clinical and Translational Imaging and Sensing of Diabetic Microangiopathy: A Narrative Review

Microvascular changes in diabetes affect the function of several critical organs, such as the kidneys, heart, brain, eye, and skin, among others. The possibility of detecting such changes early enough in order to take appropriate actions renders the development of appropriate tools and techniques an imperative need. To this end, several sensing and imaging techniques have been developed or employed in the assessment of microangiopathy in patients with diabetes. Herein, we present such techniques; we provide insights into their principles of operation while discussing the characteristics that make them appropriate for such use. Finally, apart from already established techniques, we present novel ones with great translational potential, such as optoacoustic technologies, which are expected to enter clinical practice in the foreseeable future.

Stroke risk management in carotid atherosclerotic disease: A Clinical Consensus Statement of the ESC Council on Stroke and the ESC Working Group on Aorta and Peripheral Vascular Diseases

Carotid atherosclerotic disease continues to be an important cause of stroke, often disabling or fatal. Such strokes could be largely prevented through optimal medical therapy and carotid revascularization. Advancements in discovery research and imaging along with evidence from recent pharmacology and interventional clinical trials and registries and the progress in acute stroke management have markedly expanded knowledge base for clinical decisions in carotid stenosis. Nevertheless, there is variability in carotid-related stroke prevention and management strategies across medical specialities. Optimal patient care can be achieved by (1) establishing a unified knowledge foundation and (2) fostering multi-specialty collaborative guidelines. The emergent Neuro-Vascular Team concept, mirroring the multi-disciplinary Heart Team, embraces diverse specializations, tailores personalized, stratified medicine approaches to individual patient needs, and integrates innovative imaging and risk-assessment biomarkers. Proposed approach integrates collaboration of multiple specialists central to carotid artery stenosis management such as neurology, stroke medicine, cardiology, angiology, ophthalmology, vascular surgery, endovascular interventions, neuroradiology and neurosurgery. Moreover, patient education regarding current treatment options, their risks and advantages, is pivotal, promting patient's active role in clinical care decisions. This enables optimization of interventions ranging from lifestyle modification, carotid revascularization by stenting or endarterectomy, as well as pharmacological management encompassing statins, novel lipid-lowering and antithrombotic strategies and targeting inflammation and vascular dysfunction. This consensus document provides a harmonized multi-specialty approach to multimorbidity prevention in carotid stenosis patients, based on comprehensive knowledge review, pinpointing research gaps in an evidence-based medicine approach. It aims to be a foundational tool for interdisciplinary collaboration and prioritized patient-centric decision-making.

Patients with Acute Limb Ischemia Might Benefit from Endovascular Therapy-A 17-Year Retrospective Single-Center Series of 985 Patients

Acute lower limb ischemia (ALI) is a common vascular emergency, requiring urgent revascularization by open or endovascular means. The aim of this retrospective study was to evaluate patient demographics, treatment and periprocedural variables affecting the outcome in ALI patients in a consecutive cohort in a tertiary referral center. Primary outcome events (POE) were 30-day (safety) and 180-day (efficacy) combined mortality and major amputation rates, respectively. Secondary outcomes were perioperative medical and surgical leg-related complications and the 5-year combined mortality and major amputation rate. Statistical analysis used descriptive and uni- and multivariable Cox regression analysis. In 985 patients (71 ± 9 years, 56% men) from 2004 to 2020, the 30-day and 180-day combined mortality and major amputation rates were 15% and 27%. Upon multivariable analysis, older age (30 d: aHR 1.17; 180 d: 1.27) and advanced Rutherford ischemia stage significantly worsened the safety and efficacy POE (30 d: TASC IIa aHR 3.29, TASC IIb aHR 3.93, TASC III aHR 7.79; 180 d: TASC IIa aHR 1.97, TASC IIb aHR 2.43, TASC III aHR 4.2), while endovascular treatment was associated with significant improved POE after 30 days (aHR 0.35) and 180 days (aHR 0.39), respectively. Looking at five consecutive patient quintiles, a significant increase in endovascular procedures especially in the last quintile could be observed (17.5% to 39.5%, p < 0.001). Simultaneously, the re-occlusion rate as well as the number of patients with any previous revascularization increased. In conclusion, despite a slightly increasing early re-occlusion rate, endovascular treatment might, if possible, be favorable in ALI treatment.

Apolipoprotein E (ApoE) Rescues the Contractile Smooth Muscle Cell Phenotype in Popliteal Artery Aneurysm Disease

Popliteal artery aneurysm (PAA) is the most frequent peripheral aneurysm, primarily seen in male smokers with a prevalence below 1%. This exploratory study aims to shed light on cellular mechanisms involved in PAA progression. Sixteen human PAA and eight non-aneurysmatic popliteal artery samples, partially from the same patients, were analyzed by immunohistochemistry, fluorescence imaging, Affymetrix mRNA expression profiling, qPCR and OLink proteomics, and compared to atherosclerotic (n = 6) and abdominal aortic aneurysm (AAA) tissue (n = 19). Additionally, primary cell culture of PAA-derived vascular smooth muscle cells (VSMC) was established for modulation and growth analysis. Compared to non-aneurysmatic popliteal arteries, VSMCs lose the contractile phenotype and the cell proliferation rate increases significantly in PAA. Array analysis identified APOE higher expressed in PAA samples, co-localizing with VSMCs. APOE stimulation of primary human PAA VSMCs significantly reduced cell proliferation. Accordingly, contractile VSMC markers were significantly upregulated. A single case of osseous mechanically induced PAA with a non-diseased VSMC profile emphasizes these findings. Carefully concluded, PAA pathogenesis shows similar features to AAA, yet the mechanisms involved might differ. APOE is specifically higher expressed in PAA tissue and could be involved in VSMC phenotype rescue.

The Incidence of IgG4-Related and Inflammatory Abdominal Aortic Aneurysm Is Rare in a 101 Patient Cohort

Abdominal aortic aneurysms (AAA) are the most frequent aortic dilation, with considerable morbidity and mortality. Inflammatory (infl) and IgG4-positive AAAs represent specific subtypes of unclear incidence and clinical significance. Here, histologic and serologic analyses with retrospective clinical data acquisition are investigated via detailed histology, including morphologic (HE, EvG: inflammatory subtype, angiogenesis, and fibrosis) and immunhistochemic analyses (IgG and IgG4). In addition, complement factors C3/C4 and immunoglobulins IgG, IgG2, IgG4 and IgE were measured in serum samples and clinical data uses patients' metrics, as well as through semi-automated morphometric analysis (diameter, volume, angulation and vessel tortuosity). A total of 101 eligible patients showed five (5%) IgG4 positive (all scored 1) and seven (7%) inflammatory AAAs. An increased degree of inflammation was seen in IgG4 positive and inflAAA, respectively. However, serologic analysis revealed no increased levels of IgG or IgG4. The operative procedure time was not different for those cases and the short-term clinical outcomes were equal for the entire AAA cohort. Overall, the incidence of inflammatory and IgG4-positive AAA samples seems very low based on histologic and serum analyses. Both entities must be considered distinct disease phenotypes. Short-term operative outcomes were not different for both sub-cohorts.

Completing the view - histologic insights from circular AAA specimen including 3D imaging : A methodologic approach towards histologic analysis of circumferential AAA samples

Abdominal aortic aneurysm (AAA) is a pathologic enlargement of the infrarenal aorta with an associated risk of rupture. However, the responsible mechanisms are only partially understood. Based on murine and human samples, a heterogeneous distribution of characteristic pathologic features across the aneurysm circumference is expected. Yet, complete histologic workup of the aneurysm sac is scarcely reported. Here, samples from five AAAs covering the complete circumference partially as aortic rings are investigated by histologic means (HE, EvG, immunohistochemistry) and a new method embedding the complete ring. Additionally, two different methods of serial histologic section alignment are applied to create a 3D view. The typical histopathologic features of AAA, elastic fiber degradation, matrix remodeling with collagen deposition, calcification, inflammatory cell infiltration and thrombus coverage were distributed without recognizable pattern across the aneurysm sac in all five patients. Analysis of digitally scanned entire aortic rings facilitates the visualization of these observations. Immunohistochemistry is feasible in such specimen, however, tricky due to tissue disintegration. 3D image stacks were created using open-source and non-generic software correcting for non-rigid warping between consecutive sections. Secondly, 3D image viewers allowed visualization of in-depth changes of the investigated pathologic hallmarks. In conclusion, this exploratory descriptive study demonstrates a heterogeneous histomorphology around the AAA circumference. Warranting an increased sample size, these results might need to be considered in future mechanistic research, especially in reference to intraluminal thrombus coverage. 3D histology of such circular specimen could be a valuable visualization tool for further analysis.

Targeting long non-coding RNA NUDT6 enhances smooth muscle cell survival and limits vascular disease progression

Long non-coding RNAs (lncRNAs) orchestrate various biological processes and regulate the development of cardiovascular diseases. Their potential therapeutic benefit to tackle disease progression has recently been extensively explored. Our study investigates the role of lncRNA Nudix Hydrolase 6 (NUDT6) and its antisense target fibroblast growth factor 2 (FGF2) in two vascular pathologies: abdominal aortic aneurysms (AAA) and carotid artery disease. Using tissue samples from both diseases, we detected a substantial increase of NUDT6, whereas FGF2 was downregulated. Targeting Nudt6 in vivo with antisense oligonucleotides in three murine and one porcine animal model of carotid artery disease and AAA limited disease progression. Restoration of FGF2 upon Nudt6 knockdown improved vessel wall morphology and fibrous cap stability. Overexpression of NUDT6 in vitro impaired smooth muscle cell (SMC) migration, while limiting their proliferation and augmenting apoptosis. By employing RNA pulldown followed by mass spectrometry as well as RNA immunoprecipitation, we identified Cysteine and Glycine Rich Protein 1 (CSRP1) as another direct NUDT6 interaction partner, regulating cell motility and SMC differentiation. Overall, the present study identifies NUDT6 as a well-conserved antisense transcript of FGF2. NUDT6 silencing triggers SMC survival and migration and could serve as a novel RNA-based therapeutic strategy in vascular diseases.

ZILVERPASS Study: ZILVER PTX Stent vs. Bypass Surgery in Femoropopliteal Lesions, 3 year results and economic analysis

BACKGROUND

To report the 3-year safety and effectiveness results of a multicenter, prospective, randomized controlled trial comparing the ZILVER PTX paclitaxel-eluting stent to surgical bypass and to conduct a health economic analysis up to 3-year follow-up of the two treatment modalities.

METHODS

This is a study in symptomatic TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions comparing endovascular ZILVER PTX stenting vs. surgical bypass surgery using a prosthetic graft (ClinicalTrials.gov identifier NCT01952457). Between October 2013 and July 2017, 220 patients (mean age 68.6±10.5 years; 159 men) were enrolled and randomized to the ZILVER PTX treatment group (113, 51.40%) or the bypass treatment group (107, 48.60%). One of the secondary outcomes was primary patency at 3-year, defined as no evidence of binary restenosis or occlusion within the target lesion or bypass graft based on a duplex ultrasound peak systolic velocity ratio <2.4 and no clinically-driven target lesion revascularization (TLR) in endovascular cases or reintervention to restore flow in the bypass. An economic analysis was conducted to analyze the cost differences between ZILVER PTX and bypass, which shows the perspective of the public authority/organization that pays for healthcare in the two countries (payor), Germany and USA.

RESULTS

The 3-year primary patency rate was 53.30% (95% CI 61.40% to 45.20%) for the ZILVER PTX group vs. 58.20% (95% CI 67.10% to 49.30%) for the bypass arm (P=0.9721). Freedom from TLR at 3-year was 62.80% (95% CI 72.60% to 53%) for the ZILVER PTX group vs. 65.30% (95% CI 75.40% to 55.20%) for the bypass group (P=0.635). There was also no significant difference (P=0.358) in survival rate at 3-year between the ZILVER PTX group 78.50%, (95% CI to 87.70% to 69.30%) and the bypass group 87.40% (95% CI 97.6% to 77.2%). None of the deaths was categorized as related to the procedure or device. The economic analysis, taking into account procedural-, hospitalization- and reintervention costs, showed a clear cost-benefit for Zilver PTX in both investigated countries up to 3-year follow-up: Germany (Bypass €9446 per patient versus ZILVER PTX €5755) and USA (Bypass $26,373 per patient versus ZILVER PTX $19,186).

CONCLUSIONS

The non-inferior safety and effectiveness results of the ZILVER PTX stent were associated with lower costs for the payer and confirmed that ZILVER PTX stent treatment can be considered as a valid alternative for bypass surgery in long and complex femoropopliteal lesions.

Skeletal muscle optoacoustics reveals patterns of circulatory function and oxygen metabolism during exercise

Imaging skeletal muscle function and metabolism, as reported by local hemodynamics and oxygen kinetics, can elucidate muscle performance, severity of an underlying disease or outcome of a treatment. Herein, we used multispectral optoacoustic tomography (MSOT) to image hemodynamics and oxygen kinetics within muscle during exercise. Four healthy volunteers underwent three different hand-grip exercise challenges (60s isometric, 120s intermittent isometric and 60s isotonic). During isometric contraction, MSOT showed a decrease of HbO₂, Hb and total blood volume (TBV), followed by a prominent increase after the end of contraction. Corresponding hemodynamic behaviors were recorded during the intermittent isometric and isotonic exercises. A more detailed analysis of MSOT readouts revealed insights into arteriovenous oxygen differences and muscle oxygen consumption during all exercise schemes. These results demonstrate an excellent capability of visualizing both circulatory function and oxygen metabolism within skeletal muscle under exercise, with great potential implications for muscle research, including relevant disease diagnostics.

CXCR4 - a possible serum marker for risk stratification of abdominal aortic aneurysms

Background: Abdominal aortic aneurysm (AAA) rupture is still associated with a mortality rate of 80-90%. Imaging techniques or molecular fingerprinting for patient-specific risk stratification to identify pending rupture are still lacking. The chemokine (C-X-C motif) receptor (CXCR4) activation by CXCL12 ligand has been identified as a marker of inflammation and atherosclerosis, associated with AAA. Both are highly expressed in the aortic aneurysm wall. However, it is still unclear whether different expression levels of CXCR4 and CXCL12 can distinguish ruptured AAAs (rAAA) from intact AAAs (iAAA). Patients and methods: Abdominal aortic tissue samples (rAAA: n=29; iAAA: n=54) were excised during open aortic repair. Corresponding serum samples from these patients (n=9 from rAAAs; n=47 from iAAA) were drawn pre-surgery. Healthy aortic tissue samples (n=8) obtained from adult kidney donors during transplantation and serum samples from healthy adult volunteers were used as controls (n=5 each). Results: CXCR4 was mainly expressed in the media of the aneurysmatic tissue. Focal positive staining was also observed in areas of inflammatory infiltrates within the adventitia. In tissue lysates, no significant differences between iAAA, rAAA, and healthy controls were observed upon ELISA analysis. In serum samples, the level of CXCR4 was significantly increased in rAAA by 4-fold compared to healthy controls (p=0.011) and 3.0-fold for rAAA compared to iAAA (p<0.001). Furthermore a significant positive correlation between aortic diameter and serum CXCR4 concentration was found for both, iAAA and rAAA (p=0.042). Univariate logistic regression analysis showed that increased CXCR4 serum concentrations were associated with AAA rupture (OR: 4.28, 95% CI: 1.95-12.1, p=0.001). Conclusions: CXCR4 concentration was significantly increased in serum of rAAA patients and showed a significant correlation with an increased aortic diameter. The level of CXCR4 in serum was associated with a more than 4-fold risk increase for rAAA and thus could possibly serve as a biomarker in the future. However, further validation in larger studies is required.

Non-invasive multispectral optoacoustic tomography resolves intrahepatic lipids in patients with hepatic steatosis

Hepatic steatosis is characterized by intrahepatic lipid accumulation and may lead to irreversible liver damage if untreated. Here, we investigate whether multispectral optoacoustic tomography (MSOT) can offer label-free detection of liver lipid content to enable non-invasive characterization of hepatic steatosis by analyzing the spectral region around 930 nm, where lipids characteristically absorb. In a pilot study, we apply MSOT to measure liver and surrounding tissues in five patients with liver steatosis and five healthy volunteers, revealing significantly higher absorptions at 930 nm in the patients, while no significant difference was observed in the subcutaneous adipose tissue of the two groups. We further corroborated the human observations with corresponding MSOT measurements in high fat diet (HFD) - and regular chow diet (CD)-fed mice. This study introduces MSOT as a potential non-invasive and portable technique for detecting/monitoring hepatic steatosis in clinical settings, providing justification for larger studies.

Locoregional Anaesthesia and Intra-Operative Angiography in Carotid Endarterectomy: 16 Year Results of a Consecutive Single Centre Series

OBJECTIVE

The benefit of local (LA) over general (GA) anaesthesia and the rationale of intra-operative imaging strategies during carotid endarterectomy (CEA) is debated. This study analysed the associations between patient characteristics, LA, and intra-operative imaging strategies and the in hospital stroke and death rates in elective CEA over a 16 year period.

METHODS

All consecutive patients treated by elective CEA between January 2004 and December 2019 (n = 1 872; median age 71 years, 70% male, 37% symptomatic) were included. All patients were assessed neurologically before and within 48 hours after CEA. The primary outcome event was the combined rate of any in hospital stroke or death. Secondary outcome events were the combined rates of any in hospital major stroke (modified Rankin scale [mRS] 3 - 5) or death, stroke, minor stroke (mRS 0 - 2), major stroke, and death alone. To detect changes over time, four quartiles (2004 - 2007, 2008 - 2011, 2012 - 2015, and 2016 - 2019) of this cohort were analysed. Statistical analysis comprised trend tests, and uni- and multivariable logistic regression.

RESULTS

Median patient age increased from 68 to 73 years (p < .001). Over time, LA (from 28% to 91%) and intra-operative imaging (angiography 2.8 - 98.1%, duplex ultrasound 0 - 78.2%) was applied more frequently. Surgical techniques did not change. The in hospital stroke or death and major stroke or death rates decreased from 3.7% to 1.5% (p = .041) and from 2.8% to 0.9% (p = .014), respectively, corresponding to a relative risk of decline of 7% and 12% annually. Multivariable analysis revealed that LA (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.1 - 0.62) and intra-operative angiography (OR 0.09, 95% CI 0.10 - 0.81) were associated with lower in hospital major stroke and death rates.

CONCLUSION

These data demonstrate a decline in the combined rates of any in hospital major stroke or death after non-emergency CEA over time. Locoregional anaesthesia and intra-operative quality control were associated with these improvements and might be worthwhile in elective CEA.

Artificial intelligence in atherosclerotic disease: Applications and trends

Atherosclerotic cardiovascular disease (ASCVD) is the most common cause of death globally. Increasing amounts of highly diverse ASCVD data are becoming available and artificial intelligence (AI) techniques now bear the promise of utilizing them to improve diagnosis, advance understanding of disease pathogenesis, enable outcome prediction, assist with clinical decision making and promote precision medicine approaches. Machine learning (ML) algorithms in particular, are already employed in cardiovascular imaging applications to facilitate automated disease detection and experts believe that ML will transform the field in the coming years. Current review first describes the key concepts of AI applications from a clinical standpoint. We then provide a focused overview of current AI applications in four main ASCVD domains: coronary artery disease (CAD), peripheral arterial disease (PAD), abdominal aortic aneurysm (AAA), and carotid artery disease. For each domain, applications are presented with refer to the primary imaging modality used [e.g., computed tomography (CT) or invasive angiography] and the key aim of the applied AI approaches, which include disease detection, phenotyping, outcome prediction, and assistance with clinical decision making. We conclude with the strengths and limitations of AI applications and provide future perspectives.

Why do guidelines recommend screening for abdominal aortic aneurysms, but not for asymptomatic carotid stenosis? A plea for a randomized controlled trial

BACKGROUND

Current guidelines do not recommend screening for asymptomatic carotid artery stenosis (AsxCS). The rationale behind this recommendation is that detection of AsxCS may lead to an unnecessary carotid intervention. In contrast, screening for abdominal aortic aneurysms is strongly recommended.

METHODS

A critical analysis of the literature was performed to evaluate the implications of detecting AsxCS.

RESULTS

Patients with AsxCS are at high risk for future stroke, myocardial infarction and vascular death. Population-wide screening for AsxCS should not be recommended. Additionally, screening of high-risk individuals for AsxCS with the purpose of identifying candidates for a carotid intervention is inappropriate. Instead, selective screening for AsxCS should be considered and should be viewed as an opportunity to identify individuals at high risk for atherosclerotic cardiovascular disease and future cardiovascular events for the timely initiation of intensive medical therapy and risk factor modification.

CONCLUSIONS

Although mass screening should not be recommended, there are several arguments suggesting that selective screening for AsxCS should be considered. The rationale supporting such selective screening is to optimize risk factor control and to initiate intensive medical therapy for prevention of future cardiovascular events, rather than to identify candidates for an intervention.

Cancer, cancer treatment and aneurysmatic ascending aorta growth within a retrospective single center study

Background: Multi-morbidity poses a substantial challenge for health care in an aging population. Recent studies did not provide evidence for general side effects of anti-cancer therapy regarding the growth rate of coincident abdominal aortic aneurysms, although it was suggested that specific therapeutic substances might accelerate growth. Aneurysm pathology, however, differs with respect to localization. Hence, we present the first ever analysis on the association of cancer and cancer therapy with growth alteration of aneurysms of the ascending aorta (AscAA). Patients and methods: A retrospective single-center identification of AscAA+cancer patients was performed in the institutional picture archiving and communication system (PACS). Included were all patients with ≥2 CT angiograms over ≥6 months and additional malignancy. Clinical data and aneurysm diameters were retrieved and analyzed for an association of cancer (stratified by tumor entity) or cancer therapy (stratified by several classes of chemotherapeutic agents and radiation therapy) with annual growth rate, respectively. Statistics included t-test, Wilcoxon test, and a linear regression model accounting for initial AscAA diameter and type of treatment. Results: From 2003 to 2021, 151 patients (median age 70 years; 85% male) with AscAA and coincident 163 malignancies were identified. Prostate (37%) and hematologic cancer (17%) were most frequent. One-hundred-eleven patients (74%) received chemotherapy and 75 patients (50%) had radiation. After exclusion of six patients with an initial AscAA diameter >55 mm, the average annual AscAA growth rate was 0.18±0.64 mm/year, with only 12 patients experiencing a growth rate >1mm/year. Neither tumor entity nor radiation or chemotherapy - alone or in combination - were significantly associated with an alteration of the annual AscAA growth rate. Likewise, a subanalysis for singular chemotherapeutic agents did not reveal a specific association with AscAA growth alteration. Conclusions: Growth rates of AscAA are low in this cohort with coincident malignancy. Cancer and/or chemotherapy or radiation are not associated with an alteration of the annual growth rate. Additional control examinations seem unnecessary.

Rupture risk parameters upon biomechanical analysis independently change from vessel geometry during abdominal aortic aneurysm growth

Objective

The indication for abdominal aortic aneurysm (AAA) repair is based on a diameter threshold. However, mechanical properties, such as peak wall stress (PWS) and peak wall rupture index (PWRI), influence the individual rupture risk. This study aims to correlate biomechanical and geometrical AAA characteristics during aneurysm growth applying a new linear transformation-based comparison of sequential imaging.

Methods

Patients with AAA with two sequential computed tomography angiographies (CTA) were identified from a single-center aortic database. Patient characteristics included age, gender, and comorbidities. Semiautomated segmentation of CTAs was performed using Endosize (Therenva) for geometric variables (diameter, neck configuration, α/β angle, and vessel tortuosity) and for finite element method A4 Clinics Research Edition (Vascops) for additional variables (intraluminal thrombus [ILT]), vessel volume, PWS, PWRI). Maximum point coordinates from at least one CTA 6 to 24 months before their final were predicted for the final preoperative CTA using linear transformation along fix and validation points to estimate spatial motion. Pearson's correlation and the t test were used for comparison.

Results

Thirty-two eligible patients (median age, 70 years) were included. The annual AAA growth rate was 3.7 mm (interquartile range [IQR], 2.25-5.44; P < .001) between CTs. AAA (+17%; P < .001) and ILT (+43%; P < .001) volume, maximum ILT thickness (+35%; P < .001), β angle (+1.96°; P = .017) and iliac tortuosity (+0.009; P = .012) increased significantly. PWS (+12%; P = .0029) and PWRI (+16%; P < .001) differed significantly between both CTAs. Both mechanical parameters correlated most significantly with the AAA volume increase (r = 0.68 [P < .001] and r = 0.6 [P < .001]). Changes in PWS correlated best with the aneurysm neck configuration. The spatial motion of maximum ILT thickness was 14.4 mm (IQR, 7.3-37.2), for PWS 8.4 mm (IQR, 3.8-17.3), and 11.5 mm (IQR, 5.9-31.9) for PWRI. Here, no significant correlation with any of the aforementioned parameters, patient age, or time interval between CTs were observed.

Conclusions

PWS correlates highly significant with vessel volume and aneurysm neck configuration. Spatial motion of maximum ILT thickness, PWS, and PWRI is detectable and predictable and might expose different aneurysm wall segments to maximum stress throughout aneurysm growth. Linear transformation could thus add to patient-specific rupture risk analysis.

Clinical Relevance

Abdominal aortic aneurysm rupture risk assessment is a key feature in future individualized therapy approaches for patients, since more and more data are obtained concluding a heterogeneous disease entity that might not be addressed ideally looking only at diameter enlargement. The approach presented in this pilot study demonstrates the feasibility and importance of measuring peak wall stress and rupture risk indices based on predicted and actual position of maximum stress points including intraluminal thrombus.

External Validity of Randomised Controlled Trials on Carotid Revascularisation: Trial Populations May Not Always Reflect Patients in Clinical Practice

OBJECTIVE

The external validity of randomised controlled trials (RCTs) and their transferability to clinical practice is under investigated. This study aimed to analyse the exclusion criteria of recent carotid RCTs comparing carotid endarterectomy (CEA) and carotid artery stenting, and to assess the eligibility of consecutive clinical practice cohorts to those RCTs.

METHODS

An analysis of the clinical and anatomical exclusion criteria of RCTs for asymptomatic (SPACE-2, ACST-2, CREST-1, and CREST-2) and symptomatic carotid stenosis (SPACE-1, CREST-1, ICSS, and EVA-3S) was performed. Two hundred consecutive asymptomatic and 200 consecutive symptomatic patients, treated by CEA, or transfemoral or transcarotid artery stenting at a tertiary referral university centre were assessed for their potential eligibility for each corresponding RCT. RCT patient data were pooled and differences from the clinical practice cohort analysed. Statistics were descriptive and comparative using Fisher's exact and t tests.

RESULTS

The number of clinical and anatomical exclusion criteria differed widely between RCTs. Potential eligibility rates of the clinical practice cohort for RCTs with regard to asymptomatic carotid stenosis were 80.5% (ACST-2), 79.5% (SPACE-2), 47% (CREST-1), and 20% (CREST-2). For RCTs on symptomatic carotid stenosis the eligibility rates were 89% (ICSS), 86.5% (EVA-3S), 64% (SPACE-1), and 39% (CREST-1). Both clinical practice cohorts were older by about three years and patients were more often male vs. the RCTs. Furthermore, a history of smoking (asymptomatic patients), hypertension (symptomatic patients), and atrial fibrillation was diagnosed more often, whereas hypercholesterolaemia and coronary heart disease (asymptomatic patients) were less prevalent. More clinical practice patients were on antiplatelets, anticoagulants, and lipid lowering drugs. Symptomatic clinical practice patients presented more often with retinal ischaemia and less often with minor hemispheric strokes than patients in the RCTs.

CONCLUSION

The external validity of contemporary carotid RCTs varies considerably. Patients in routine clinical practice differ from RCT populations with respect to age, comorbidities, and medication. These data are of interest for clinicians and guideline authors and may be relevant for the design of future comparative trials.

Carotid endarterectomy or stenting or best medical treatment alone for moderate-to-severe asymptomatic carotid artery stenosis: 5-year results of a multicentre, randomised controlled trial

BACKGROUND

The optimal treatment for patients with asymptomatic carotid artery stenosis is under debate. Since best medical treatment (BMT) has improved over time, the benefit of carotid endarterectomy (CEA) or carotid artery stenting (CAS) is unclear. Randomised data comparing the effect of CEA and CAS versus BMT alone are absent. We aimed to directly compare CEA plus BMT with CAS plus BMT and both with BMT only.

METHODS

SPACE-2 was a multicentre, randomised, controlled trial at 36 study centres in Austria, Germany, and Switzerland. We enrolled participants aged 50-85 years with asymptomatic carotid artery stenosis at the distal common carotid artery or the extracranial internal carotid artery of at least 70%, according to European Carotid Surgery Trial criteria. Initially designed as a three-arm trial including one group for BMT alone (with a randomised allocation ratio of 2·9:2·9:1), the SPACE-2 study design was amended (due to slow recruitment) to become two substudies with two arms each comparing CEA plus BMT with BMT alone (SPACE-2a) and CAS plus BMT with BMT alone (SPACE-2b); in each case in a 1:1 randomisation. Participants and clinicians were not masked to allocation. The primary efficacy endpoint was the cumulative incidence of any stroke or death from any cause within 30 days or any ipsilateral ischaemic stroke within 5 years. The primary safety endpoint was any stroke or death from any cause within 30 days after CEA or CAS. The primary analysis was by intention-to treat, which included all randomly assigned patients in SPACE-2, SPACE-2a, and SPACE-2b, analysed using meta-analysis of individual patient data. We did two-step hierarchical testing to first show superiority of CEA and CAS to BMT alone then to assess non-inferiority of CAS to CEA. Originally, we planned to recruit 3640 patients; however, the study had to be stopped prematurely due to insufficient recruitment. This report presents the primary analysis at 5-year follow-up. This trial is registered with ISRCTN, number ISRCTN78592017.

FINDINGS

513 patients across SPACE-2, SPACE-2a, and SPACE-2b were recruited and surveyed between July 9, 2009, and Dec 12, 2019, of whom 203 (40%) were allocated to CEA plus BMT, 197 (38%) to CAS plus BMT, and 113 (22%) to BMT alone. Median follow-up was 59·9 months (IQR 46·6-60·0). The cumulative incidence of any stroke or death from any cause within 30 days or any ipsilateral ischaemic stroke within 5 years (primary efficacy endpoint) was 2·5% (95% CI 1·0-5·8) with CEA plus BMT, 4·4% (2·2-8·6) with CAS plus BMT, and 3·1% (1·0-9·4) with BMT alone. Cox proportional-hazard testing showed no difference in risk for the primary efficacy endpoint for CEA plus BMT versus BMT alone (hazard ratio [HR] 0·93, 95% CI 0·22-3·91; p=0·93) or for CAS plus BMT versus BMT alone (1·55, 0·41-5·85; p=0·52). Superiority of CEA or CAS to BMT was not shown, therefore non-inferiority testing was not done. In both the CEA group and the CAS group, five strokes and no deaths occurred in the 30-day period after the procedure. During the 5-year follow-up period, three ipsilateral strokes occurred in both the CAS plus BMT and BMT alone group, with none in the CEA plus BMT group.

INTERPRETATION

CEA plus BMT or CAS plus BMT were not found to be superior to BMT alone regarding risk of any stroke or death within 30 days or ipsilateral stroke during the 5-year observation period. Because of the small sample size, results should be interpreted with caution.

FUNDING

German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG).

Radiation and chemotherapeutics are associated with altered aortic aneurysm growth in cancer patients

INTRODUCTION

Co-prevalence of aorto-iliac aneurysm (i.e. AAA) and cancer confronts patients and physicians with two life-threatening diseases. Modern chemotherapeutics and target therapies might impact the aneurysm wall integrity and subsequently affect growth. The purpose of this study was to assess associations between malignancy, therapeutic regimens and the growth rates of aorto-iliac aneurysms.

PATIENTS AND METHODS

A retrospective single-center analysis identified patients with aneurysm + cancer. Patients with ≥2 CT angiograms over ≥6 months and additional malignancy were included. Clinical data and aneurysm diameters were analyzed. AAA growth under cancer therapy (chemotherapy/radiation) was compared to a non-cancer AAA control cohort and to meta-analysis data. Statistics included t-tests and a linear regression model with correction for initial aortic diameter and type of treatment.

RESULTS

From 2003 - 2020, 217 patients (median age 70 years; 92% male) with 246 aneurysms (58.8% AAA) and 238 malignancies were identified. Prostate (27%) and lung (16%) cancer were most frequently seen, 157 patients (72%) received chemotherapy and 105 patients (48%) radiation, thereof 79 (36.4%) both. Annual AAA growth was not significantly different for cancer and non-cancer patients (2.0±2.3 vs. 2.8±2.1mm/y, p=0.20). However, subgroup analyses revealed that radiation was associated with a significantly reduced aneurysm growth rate compared to cancer patients without radiation (1.1±1.3 vs. 1.6±2.1 mm/y, p=0.046) and to the non-cancer control cohort (1.7±1.9 vs. 2.8±2.1 mm/y, p=0.007). Administration of antimetabolites showed significantly increased AAA growth (+0.9mm/year, p=0.011), while e.g. topoisomerase inhibitors (-0.8mm/year, p=0.17) and anti-androgens (-0.5mm/year, p=0.27) showed a possible trend for reduced growth. Similar was observed for iliac aneurysms (n=85). Additionally, effects were persistent in combinations of chemotherapies (2.6±1.4 substances/patient).

CONCLUSION

Cancer patients with concomitant aortic aneurysms may require intensified monitoring when undergoing specific therapies, such as antimetabolites, since they may experience an increased aneurysm growth rate. Radiation may be associated with reduced aneurysm growth.

Can We Still Teach Open Repair of Abdominal Aortic Aneurysm in The Endovascular Era? Single-Center Analysis on The Evolution of Procedural Characteristics Over 15 Years

OBJECTIVE

In many vascular centers an endovascular first policy for the treatment of abdominal aortic aneurysms (AAA) has resulted in endovascular aortic repair (EVAR) outnumbering open aortic repair (OAR). The declining routine in OAR raises the question whether this might influence procedural outcomes and diminish surgical expertise for current and future vascular surgeons. We aimed to analyze OAR outcomes, AAA morphology and procedural details over the past 15 years while an endovascular first approach was successively implemented.

PARTICICPANTS AND DESIGN

All patients operated for (i)ntact infra-/juxtarenal AAA between January 1, 2005 and December 31, 2019 were identified. Outcome parameters were length of stay (hospital/ICU), in-hospital mortality and medical/surgical complications. Operative details were clamping zone, access and graft configuration. AAA anatomy including neck and iliac parameters was analyzed with Endosize©. Logistic regression, uni- and multivariate analysis were applied.

RESULTS

293 patients received elective OAR for iAAA. Baseline characteristics (age, sex, hypertension, smoking, occlusive disease, coronary disease, hyperlipidemia, diabetes, renal insufficiency and obesity) did not change over time. The number of OAR dropped significantly (-0.5 cases/year p = 0.02). The procedure time (2005-2007: 192.2 ± 87.5min to 2017-2019: 235.6 ± 88.2min; p = 0.0001) and the length of stay (2005-2007: 12.0 ± 7.9 to 2017-2019: 17.0 ± 23.1; p = 0.03) increased significantly, whereas the in-hospital mortality, length of ICU stay and complication rates didn't, nor did AAA anatomy. Upon multivariate analysis, annual number of OAR and any additional anastomosis significantly influenced procedure time, trainee involvement, for example, did not. Hospital length-of-stay depended on patient age (p = 0.002), complication rates (p < 0.0001) and procedure time (p = 0.006).

CONCLUSION

Mortality and complication rates for OAR have remained low and constant. With the increase of EVAR, the absolute number of OARs has decreased significantly. However, the total procedure time has increased and depends significantly on the annual number of OARs in total and per surgeon. This might influence outcome parameters and should be implanted in future surgical education.

Learning curve and proficiency metrics for transcarotid artery revascularization

BACKGROUND

When introduced to a new procedure, physicians improve their performance and reduce their procedural adverse event rates rapidly during the initial cases and then improvement slows, signaling that proficiency has been achieved. Determining when they have acquired proficiency has important implications for procedural innovation, education, credentialing, and patient safety. We analyzed the worldwide experience with transcarotid artery revascularization (TCAR), a hybrid approach to carotid revascularization, to identify the (1) procedural performance measures associated with clinical and technical adverse events; (2) target levels of performance measures that minimize adverse event rates; and (3) number of TCAR cases needed to achieve the target levels for the performance measures.

METHODS

The patient, lesion, and physician characteristics were collected for each TCAR procedure performed by each physician worldwide in an international quality assurance database. Four procedural performance measures were recorded for each procedure: flow-reversal time, fluoroscopy time, contrast volume, and total skin-to-skin time. Composite clinical adverse events (ie, transient ischemic attack, stroke, myocardial infarction, death) and composite technical adverse events (ie, aborted procedure, conversion to surgery, bleeding, dissection, cranial nerve injury, device failure), occurring within 24 hours were also recorded. Correlations between each performance measure and the clinical and technical adverse event rates were computed. The inflection points in the performance measures were identified at which no further improvements occurred in the adverse event rates. Finally, the minimum number of TCAR cases required to achieve the target performance measure levels was computed.

RESULTS

A total of 18,240 procedures performed by 1273 physicians were analyzed. Of the 18,240 patients, 34.9% were women and 62.5% were asymptomatic. The flow-reversal time correlated with clinical adverse events adjusted for age, sex, and symptomatic status (R2 = 0.91; P < .0001) and adjusted technical adverse events (R2 = 0.86; P < .0001). The skin-to-skin time correlated with adjusted technical adverse events (R2 = 0.92; P < .0001). A reduction in flow-reversal times to <13.1 minutes and the skin-to-skin time to <81 minutes did not translate into further improvements in the adverse event rates. A minimum of 26 TCAR cases was required to achieve the target flow-reversal time, and a minimum of 15 cases was required to achieve the target skin-to-skin time.

CONCLUSIONS

The flow-reversal time and skin-to-skin time are appropriate performance measures for establishing the level of expertise of physicians as they acquire skills to perform TCAR. A target time of ≤13.1 minutes for flow-reversal and 81 minutes for skin-to-skin time minimized the adverse event rates. Familiarity with the steps involved in performing TCAR was achieved after ≥15 cases, and minimizing clinical adverse events occurred after ≥26 cases.

Abstract 216: Single-cell And Spatially Resolved Transcriptome Analysis Reveals Cellular Heterogeneities And Novel Regulators Of Atherosclerotic Plaque Destabilization

Background: Cardiovascular diseases, including atherosclerosis, are the major cause of death in western societies, still molecular mechanisms of plaque destabilization remain unclear. Long non-coding RNAs (lncRNAs) are one example of novel molecular modulators, as their expression is highly cell-type specific.

Methods: We utilized combined total (bulk) RNA and single cell (sc) RNA to study the transcriptome of advanced carotid artery lesions from patients undergoing carotid endarterectomy in our vascular surgery clinic. Additionally, we performed hybridization-based RNA in situ sequencing (HybRISS) to indicate where cluster-defining genes are located within the plaques.

Results: In this current study, four sequencing datasets were investigated (total RNA from early vs. late lesions from the same individual patient and unstable vs. stable lesions from individual patients; two separate scRNA-seq datasets).16 lncRNAs were cross-referenced between all four datasets. All of these lncRNAs presented a cell-type specific expression pattern, with 11 lncRNAs being significantly enriched in different smooth muscle cell (SMC) clusters. We found all newly identified lncRNAs conserved in our scRNA-seq datasets of genetically mutated ( LDLR-/- ) Yucatan mini-pigs and the inducible carotid artery plaque rupture mice ( ApoE-/- ). The cluster-defining genes from the human scRNA-seq data were then located in human carotid artery tissue sections using the HybRISS method to unravel their distinct location within these plaques.

Discussion: Taken together, our datasets, methods and different animal-models demonstrate that combining bulk with scRNA-seq data and spatially resolved sequencing methods are powerful tools to identify and characterize novel lncRNAs being expressed by a certain cell-type in the disease progression.

Abstract 353: Phenotypic Switching Of Vascular Smooth Muscle Cells Is Regulated By ApoE And A Potential Therapeutic Target In Popliteal Aneurysms

Introduction: Popliteal artery aneurysm (PAA) is an individually highly fatal disease, causing ischemia and eventual major amputation, mainly in 50-70-year-old males. It is the most frequent peripheral artery aneurysm and correct treatment is challenging for clinicians, since both open and endovascular repair have only modest success rates, depending on the clinical presentation. In comparison to other aneurysm entities, little is known about its specific pathogenesis.

Material and Methods: 26 Human PAA and popliteal artery samples were analyzed by immunohistochemistry, mRNA and miRNA expression analysis and targeted proteomics (OLink platform) to identify key features of the disease and crucial pathways involved. Additionally, a primary cell culture of PAA specimen was established for in-vitro vascular smooth muscle cell (VSMC) modulation.

Results: VSMCs lose their contractile phenotype along with significant inflammatory and proteolytic changes in the vessel wall architecture. Extensive tissue remodeling with high cell turnover rates (as indicated by Ki67+ cells) compared to non-diseased popliteal artery is a unique feature in comparison to AAA. This correlates with highly abundant co-expression of the apolipoproteins E and CI with Ki67 in VSMCs in double immune-fluorescent stains. Stimulation of VSMCs with external APOE or APOCI alters proliferation rates and significantly changes a subset of contractile markers proteins upon gene expression analysis. These findings are emphasized by a specific case of a solely mechanically induced PAA in a young male.

Conclusion: Pathogenesis of PAA shows similar histologic features than AAA, yet differs in key pathways involved. Increased cell turnover in the aneurysm neck area suggests evaluation of alternative treatment strategies, i.e., targeting key processes of pathogenesis such as angiogenesis and cell turnover.

Neuroimmune cardiovascular interfaces control atherosclerosis

Atherosclerotic plaques develop in the inner intimal layer of arteries and can cause heart attacks and strokes¹. As plaques lack innervation, the effects of neuronal control on atherosclerosis remain unclear. However, the immune system responds to plaques by forming leukocyte infiltrates in the outer connective tissue coat of arteries (the adventitia)^2-6. Here, because the peripheral nervous system uses the adventitia as its principal conduit to reach distant targets^7-9, we postulated that the peripheral nervous system may directly interact with diseased arteries. Unexpectedly, widespread neuroimmune cardiovascular interfaces (NICIs) arose in mouse and human atherosclerosis-diseased adventitia segments showed expanded axon networks, including growth cones at axon endings near immune cells and media smooth muscle cells. Mouse NICIs established a structural artery-brain circuit (ABC): abdominal adventitia nociceptive afferents^10-14 entered the central nervous system through spinal cord T₆-T₁₃ dorsal root ganglia and were traced to higher brain regions, including the parabrachial and central amygdala neurons; and sympathetic efferent neurons projected from medullary and hypothalamic neurons to the adventitia through spinal intermediolateral neurons and both coeliac and sympathetic chain ganglia. Moreover, ABC peripheral nervous system components were activated: splenic sympathetic and coeliac vagus nerve activities increased in parallel to disease progression, whereas coeliac ganglionectomy led to the disintegration of adventitial NICIs, reduced disease progression and enhanced plaque stability. Thus, the peripheral nervous system uses NICIs to assemble a structural ABC, and therapeutic intervention in the ABC attenuates atherosclerosis.

Comparison of Recent Practice Guidelines for the Management of Patients With Asymptomatic Carotid Stenosis

Despite the publication of several national/international guidelines, the optimal management of patients with asymptomatic carotid stenosis (AsxCS) remains controversial. This article compares 3 recently released guidelines (the 2020 German-Austrian, the 2021 European Stroke Organization [ESO], and the 2021 Society for Vascular Surgery [SVS] guidelines) vs the 2017 European Society for Vascular Surgery (ESVS) guidelines regarding the optimal management of AsxCS patients.The 2017 ESVS guidelines defined specific imaging/clinical parameters that may identify patient subgroups at high future stroke risk and recommended that carotid endarterectomy (CEA) should or carotid artery stenting (CAS) may be considered for these individuals. The 2020 German-Austrian guidelines provided similar recommendations with the 2017 ESVS Guidelines. The 2021 ESO Guidelines also recommended CEA for AsxCS patients at high risk for stroke on best medical treatment (BMT), but recommended against routine use of CAS in these patients. Finally, the SVS guidelines provided a strong recommendation for CEA+BMT vs BMT alone for low-surgical risk patients with >70% AsxCS. Thus, the ESVS, German-Austrian, and ESO guidelines concurred that all AsxCS patients should receive risk factor modification and BMT, but CEA should or CAS may also be considered for certain AsxCS patient subgroups at high risk for future ipsilateral ischemic stroke.