Collateral Supply Research Articles

Quantitative Easing, Safe Asset Scarcity and Bank Lending

The Eurosystem's Public Sector Purchase Programme (PSPP) increased the scarcity of safe assets, which caused significant declines and substantial dispersion in European repo rates. However, banks holding these safe assets benefited from this development: First, using the German security register, this paper shows that scarcity affects bank funding costs, as their collateral supply is determined by their ex ante securities holdings and repo rates. Second, it makes use of the German credit register to show that asset scarcity had real effects: Banks more exposed to asset scarcity increased their credit supply.

The Preferential Treatment of Green Bonds

We study the preferential treatment of green bonds in the Central Bank collateral framework as an environmental policy instrument within a DSGE model with environmental and financial frictions. Green and conventional entrepreneurs issue bonds to banks that use them as collateral. The associated collateral premium induce entrepreneurs to increase bond issuance, investment, leverage, and default risk. Collateral policy solves a trade-off between increasing collateral supply, adverse effects on entrepreneur risk-taking, and subsidizing green investment. Due to these adverse side effects, optimal collateral policy is characterized by modest preferential treatment, thereby increasing the green bond share and, to a smaller extent, the green investment share, which in turn reduces pollution. The limited response of green investment is directly related to higher risk-taking of green entrepreneurs. Furthermore, we show that preferential treatment is an imperfect substitute of Pigouvian taxation on pollution: only if the optimal tax can not be implemented, optimal collateral policy features preferential treatment of green bonds.

Functioning arterial or venous riolan arch in localized pancreatic cancer. how it can change tactics?

Background: CT are obligatory before pancreatic surgery. Discovery of functioning arterial or venous Riolan arch (FRA) can have substantial influence on tactics. Aim: To assess importance of FRA discloser for decision making before pancreatic surgery. Patients: Retrospective analysis of 554 patients' consecutive preoperative CT data revealed arterial(n2) and venous(n5) FRA in 7 cases. Modification of treatment were assessed. Results: Arterial FRA was found in pancreatic body cancer(n2). 1.atherosclerotic occlusion of CA and SMA with symptomatic abdominal ischemia; 2.tumor involved CA on the background of endoluminally unreсonstructable SMA occlusion. In the first case CA stenting before distal pancreatectomy eliminated symptoms fully. In the second case after FOLFIRINOXn12 R0 DPCAR without SMA reconstruction was done because of good collateral supply. Uneventful postop period, discharge on days 10 and 13. Venous FRA in all the cases of PDAC of the head±body were the sign of full block of all SMV tributaries and already formed outflow through the splenic(SV) and/or inferior mesenteric(IMV) vein. In all these cases efficient neoadjuvant therapy and venous FRA were the weighty argument for pancreatic resection. Thrice it was done without venous reconstruction, twice with IMV transposition in SV, once with SMA resection. Uneventful postop period, discharge on days 10-19. One patient died 44 month (distant mets), the second died 19 months disease-free (MI), others alive 21,18,13,12 and 11 months after treatment. Conclusion: Delineation of FRA before pancreatic surgery is the indication for tactics change: endovascular treatment for arterial FRA and more aggressive surgery in case of venous FRA.

Ct-angiography in assessment of critical occlusive carotid artery disease

Occlusive carotid artery disease is still one of the major causes of ischemic stroke in the world. Progression of severe carotid stenosis may lead to critical stenosis and vascular occlusion. Nevertheless, there is still no pure definition of the concept of critical occlusive carotid artery disease. To define the role of CT-angiography in assessment of critical occlusive carotid artery disease. We analyzed data of 405 patients who underwent preoperative precise assessment of carotid arteries and subsequent surgical treatment for the period from 2016 to 2019. Contrast-enhanced CT-angiography (Philips Ict scanner, 256 slices) was made after previous ultrasound. Contrast agent injection rate was 4-5 ml/sec. CT angiography data were assessed according to a specialized protocol. Critical occlusive carotid artery disease was observed in 128 (31.6%) cases including critical stenosis (24.94%), near-occlusion (5.92%) and local occlusion (0.74%). Critical stenosis was characterized by local narrowing ≥90% and normal diameter of distal arterial segment. In case of near-occlusion, local critical stenosis was accompanied by narrowing of distal arterial segment. In case of local occlusion, distal collateral supply of internal carotid artery occurred through atypically originating ascending pharyngeal artery. Patients with near-occlusion and local occlusion of internal carotid artery had no signs of ICA hypoplasia and intracranial stenoses. All elements of circle of Willis were observed in 70% of patients. State of distal segment of internal carotid artery can be considered as a differential diagnostic criterion for critical occlusive carotid disease variants. CT-angiography provides all necessary data and can be recommended for precise preoperative assessment.

Endovascular Treatment of Intracranial Vertebral Artery Dissection.

Intracranial vertebral artery dissection (VAD) is the most common arterial dissection in intracranial arteries. Some types of VAD can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis, whereas others can progress to stroke that needs treatment. Recently, endovascular treatment (EVT) has emerged and is suggested as a treatment option for VADs due to perceived low rates of procedure-related morbidity with good efficacy. In the last decade, we have accumulated our strategies to treat those VADs. Here, we try to share our experiences about VADs, including indications and methods of treatment of VADs using EVT. We perform EVT for ruptured VADs presenting with SAH and some of unruptured VADs such as VAD with recurrent or progressive ischemia, dissecting aneurysm larger than 7 mm or with mass effect, early ugly change of VADs in shape and size during follow-up period, involving the basilar artery (BA) and bilateral VADs. We present how we have done in our real practice for the last decade for treating VADs by EVT rather than reviewing and organizing so-far-published literature. We tended to occlude the rupture point by vertebral artery (VA) occlusion in non-dominant VA or stent-assisted coiling in dominant VA for ruptured VADs. We tended to reconstruct original hemodynamics using various stents for unruptured VADs. To decide what to treat and how to treat are very complicated for VADs. However, we believe that EVT is the current mainstay for treating VADs. Each technique of EVT should be determined on a case-by-case basis at the discretion of endovascular neurosurgeons and/or interventional neuroradiologists according to presenting symptoms, hemodynamic status, including sufficiency of the collateral supply and anatomic features of the vertebrobasilar artery as well as the posterior inferior cerebellar artery, anterior spinal artery, and medullary perforators.

Distal Vessel Imaging via Intra-arterial Flat Panel Detector CTA during Mechanical Thrombectomy.

Obtaining information on invisible vasculature distal to the occlusion site helps to deploy a stent retriever safely during mechanical thrombectomy for large-vessel occlusion. It is essential to reduce the amount of contrast used for detecting the vessels distal to the occlusion site because acute ischemic stroke patients tend to have chronic kidney disease and patients with severe chronic kidney disease are at an increased risk of contrast-associated acute kidney injury. We assessed whether vessels distal to the occlusion site during acute ischemic stroke with large-vessel occlusion could be visualized on angiographic images using flat panel detector CT acquired following intra-arterial diluted contrast injection, compared with MRA findings. Between May 2019 and January 2020, we enrolled 28 consecutive patients with large-vessel occlusions of the anterior circulation eligible for mechanical thrombectomy following MR imaging. The patients underwent CBV imaging using flat panel detector CT with an intra-arterial diluted contrast injection instead of intravenous injection. Flat panel detector CT angiographic images reconstructed from the same dataset were evaluated for image quality, collateral status of the MCA territory, and visualization of the vessels distal to the occlusion site. These findings were compared with MRA findings. Twenty-two patients were retrospectively examined. Flat panel detector CT angiographic image quality in 20 patients (91%) was excellent or good. The distal portion of the occluded vessel segment was visualized in 14 patients (70%), while the proximal portion of the segment adjacent to the occluded vessel in 3 (15%) was visualized. No visualization was observed in only 1 patient (5%) with no collateral supply. Flat panel detector CT angiographic images were shown to evaluate vessels distal to the occlusion site more accurately than MRA. In acute ischemic stroke with large-vessel occlusion, flat panel detector CT angiographic images could successfully visualize vessels distal to the occlusion site with a small amount of contrast material.

Ischemia of the Thumb: A Rare Case of Emboli to the Princeps Pollicis Artery

Acute digital ischemia is relatively rare due to collateral blood supply to the hand from ulnar and radial arteries. We present a case of thumb ischemia secondary to embolic occlusion of the princeps pollicis artery, a branch of the radial artery, with concomitant atherosclerotic occlusion of the ipsilateral subclavian artery. This case highlights the importance of thorough investigation for systemic causes of distal upper extremity ischemia.

Clinical outcome and analysis of procedural failure during uterine artery chemoembolisation as a treatment of caesarean scar pregnancy.

IntroductionCaesarean scar pregnancy (CSP) is a relatively rare yet life-threatening condition in which the embryo is implanted in the scar after caesarean section. Recent studies have reported that uterine artery chemoembolisation (UAC) can be safe and effective method in treating CSP.AimTo present the clinical outcome of UAC with a mixture of methotrexate and gelatine sponge for the treatment of CSP and analysis of procedural failure.Material and methodsForty-one patients diagnosed with CSP were treated with selective endovascular chemoembolisation of uterine arteries. Short- and long-term results, reasons for procedural failure, and clinical outcome were analysed.ResultsPrimary procedure failed in 7 out of 41 (17%) cases. In 4 cases additional blood supply to the CSP was disclosed; 3 out of 4 from an ovarian artery and one from a superior vesical artery. In other 3 patients, reperfusion of uterine arteries was observed. All these 7 patients underwent successful secondary embolisation. The majority of the followed-up patients reported regular menses after the intervention. Four women suffered from amenorrhoea and 2 from hypomenorrhoea that continued after 90 days. Twelve patients expressed the desire for subsequent pregnancy. From this group, 5 conceived within a year of the procedure. The rest did not achieve a pregnancy.ConclusionsUAC proved to be a safe and effective method and should be considered as an option for CSP treatment, especially for women hoping to preserve their fertility. However, the presence of collateral blood supply should always be considered.

Low-dose intracoronary alteplase during primary percutaneous coronary intervention in patients with acute myocardial infarction: the T-TIME three-arm RCT

Background Microvascular obstruction commonly affects patients with acute ST-segment elevation myocardial infarction and is independently associated with adverse outcomes. Objective To determine whether or not a strategy involving low-dose intracoronary fibrinolytic therapy infused early after coronary reperfusion will reduce microvascular obstruction. Design This was a multicentre, randomised, double-blind, parallel-group, placebo-controlled, dose-ranging trial. Setting The trial took place at 11 hospitals in the UK between 17 March 2016 and 21 December 2017. Participants Patients with acute ST-segment elevation myocardial infarction and a symptom onset to reperfusion time of ≤ 6 hours were eligible for randomisation. Radial artery access was a requirement, and further angiographic criteria included a proximal-to-middle coronary artery occlusion or impaired coronary flow in the presence of a definite thrombus in the culprit coronary artery. Exclusion criteria included a functional coronary collateral supply to the infarct-related artery, any contraindication to fibrinolysis and lack of informed consent. Additional exclusion criteria for safety were (1) requirement for immunosuppressive drug therapy for ≤ 3 months and (2) treatment with an antimicrobial agent. Intervention A total of 440 participants were randomly assigned 1 : 1 : 1 to treatment with placebo (n = 151), 10 mg of alteplase (n = 144) or 20 mg of alteplase (n = 145) administered by manual infusion directly into the infarct-related coronary artery over 5–10 minutes. The intervention was scheduled to happen after reperfusion and before stent implantation. Outcomes The primary outcome was the amount of microvascular obstruction (percentage of left ventricular mass) demonstrated by contrast-enhanced cardiac magnetic resonance imaging at 2–7 days after enrolment. The primary analysis was the comparison between the 20 mg of alteplase group and the placebo group; if this comparison was not significant, the comparison of the 10 mg of alteplase group with the placebo group was considered as a secondary analysis. Sample size A total of 618 patients (minimum of 558 patients). Recruitment was halted on 21 December 2017 given that conditional power for the primary outcome based on a prespecified analysis of the first 267 randomised participants was < 30% in both treatment groups (futility criterion). Methods The primary outcome was compared between groups using a stratified Wilcoxon rank-sum test (van Elteren test), stratified by the location of the myocardial infarction. Results Among the 440 patients (mean age of 60.5 years; 15% women), the primary end point was measured in 396 (90%) patients, 17 (3.9%) withdrew, seven died and all other patients were followed up to 3 months. The amount (mean percentage of left ventricular mass) of microvascular obstruction was 2.3% versus 2.6% versus 3.5% in the placebo, 10 mg of alteplase and 20 mg of alteplase groups, respectively. In the primary analysis, microvascular obstruction did not differ between the 20 mg of alteplase group and the placebo group: 3.5% versus 2.3%, estimated difference 1.16% (95% confidence interval –0.08% to 2.41%; p = 0.32). In the secondary analysis, microvascular obstruction did not differ between the 10 mg of alteplase group and the placebo group: 2.6% versus 2.3%, estimated difference 0.29% (95% confidence interval –0.76% to 1.35%; p = 0.74). By 3 months, major adverse cardiac events (cardiac death, non-fatal myocardial infarction and unplanned hospitalisation for heart failure) had occurred in 15 (10.1%) patients in the placebo group, 18 (12.9%) in the 10 mg of alteplase group and 12 (8.2%) in the 20 mg of alteplase group. Conclusions Adjunctive low-dose intracoronary alteplase given during the primary percutaneous intervention did not reduce microvascular obstruction compared with placebo. Limitations Premature discontinuation of enrolment limited the power of the secondary and safety analyses. Future work Low-dose intracoronary alteplase or tenecteplase could be compared with placebo at the end of primary percutaneous coronary intervention in patients with an ischaemic time of < 4 hours. Trial registration This trial is registered as ClinicalTrials.gov NCT02257294. Funding This project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council (MRC) and National Institute for Health Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 7, No. 5. See the NIHR Journals Library website for further project information.

Corpus callosum infarction: a case report

Infarctions of corpus callosal are rare due to an abundant collateral blood supply. Few case reports published in the literature regarding the corpus callosum infarction. We present a case of corpus callosum infarction in a 66-year-old man with a history of diabetes mellitus, hypertension, and coronary artery disease who presented to the emergency room with left lower limb weakness. Diagnosed was made based on magnetic resonance imaging and treated conservatively.

Arterial Steal to the Penumbra Area in Patients with Acute MCA Occlusion: A Quantitative Angiographic Analysis.

PurposeIn acute middle cerebral artery (MCA) occlusion, collateral vessels provide retrograde supply to the occluded territory. We hypothesized that such collateral flow reduces perfusion of the non-occluded donor region (steal effect).Materials and MethodsPatients with an MCA occlusion with opacification of both ipsi- and contralateral anterior cerebral arteries (ACA) on angiography prior to endovascular treatment were selected. Arteriovenous transit time (AVTT) for both ACA territories was compared for different grades of collateral supply to the MCA territory. In addition, the influence of diabetes and hypertension was analyzed. After successful revascularization, AVTT was re-assessed to determine reversibility.ResultsForty-one patients were analyzed. An AVTT of 8.6 seconds (standard deviation [SD] 2.4 seconds) was seen in the ACA territory of the affected hemisphere in comparison to 6.6 seconds (SD 2.1 seconds) for the contralateral side (P<0.001). A more prolonged (but not significant) AVTT was seen in cases with a higher collateral grade. No difference in AVTT was seen in patients with diabetes or hypertension. After successful MCA revascularization, AVTT delay was 7.4 seconds (SD 2.1 seconds).ConclusionA cerebral steal effect occurs in patients with an acute MCA occlusion, probably related to augmented flow to the penumbra area.

Successful basilar artery dilatation in pure bilateral cerebral peduncular infarctions using balloon angioplasty.

•An extremely rare case of bilateral cerebral peduncular infarctions (BCPI) is reported.•The detection of the pure Mickey Mouse ears sign on MRI is an indicator of a need for reperfusion therapy.•Severe stenosis of the basilar artery (BA) and a poor collateral supply from both posterior cerebral arteries were seen.•Balloon angioplasty for the BA stenosis ameliorated the stenosis and produced a favorable outcome.

Evolution of spontaneous dissecting mycotic Superior Mesenteric aneurysm in a 12-year-old child: A case report

Visceral artery aneurysms are uncommon especially in children. One of the main complications before surgery is rupture. This 12-year-old child presented with a large, fast growing, mycotic superior mesenteric aneurysm that had all the favourable conditions for rupture. There was spontaneous dissection of the weakened media with partial erosion of the aneurysm into the wall of the third part of the duodenum. However, this aneurysm formed a thrombus that gradually occluded the lumen. This led to formation of collateral vessels for the continued vascular supply of the midgut. The uniqueness of this case report has been highlighted from several points (the rarity of the condition in children, the favorability of the conditions to rupture, the gradual but complete luminal occlusion with the eventual formation of collaterals to supply the midgut, and the spontaneous medial dissection with partial duodenal wall erosion without causing rupture). Although there is no standard surgical approach, early elective surgery is recommended. Nonoperative approach is an option that should aim at reducing the risk for rupture. Control of blood pressure is key. This child underwent surgery. Under total vascular exclusion, the aneurysm was opened. After total luminal occlusion and collateral blood supply to midgut was noted, infected thrombus was evacuated and the aneurysm walls debrided.

Utility of Leptomeningeal Collaterals in Predicting Intracranial Atherosclerosis-Related Large Vessel Occlusion in Endovascular Treatment.

Earlier or preprocedural identification of occlusion pathomechanism is crucial for effective endovascular treatment. As leptomeningeal collaterals tend to develop well in chronic ischemic conditions such as intracranial atherosclerosis (ICAS), we investigated whether leptomeningeal collaterals can be a preprocedural marker of ICAS-related large vessel occlusion (ICAS-LVO) in endovascular treatment. A total of 226 patients who underwent endovascular treatment were retrospectively reviewed. We compared the pattern of leptomeningeal collaterals between patients with ICAS-LVO and without. Leptomeningeal collaterals were assessed by preprocedural computed tomography angiography (CTA) and basically categorized by three different collateral assessment methods. Better leptomeningeal collaterals were significantly associated with ICAS-LVO, although they were not independent for ICAS-LVO. When leptomeningeal collaterals were dichotomized to incomplete (<100%) and complete (100%), the latter was significantly more frequent in patients with ICAS-LVO (52.5% versus 20.4%) and remained an independent factor for ICAS-LVO (odds ratio, 3.32; 95% confidence interval, 1.52–7.26; p = 0.003). The area under the curve (AUC) value of complete leptomeningeal collateral supply was 0.660 for discrimination of ICAS-LVO. Incomplete leptomeningeal collateral supply was not likely ICAS-LVO, based on the high negative predictive value (88.6%). Considering its negative predictive value and the independent association between complete leptomeningeal collateral supply and ICAS-LVO, leptomeningeal collaterals could be helpful in the preprocedural determination of occlusion pathomechanism.

Coronary physiology before and after chronic total occlusion treatment: what does it tell us?

Studies performed in the last two decades demonstrate that after successful percutaneous coronary intervention (PCI) of a chronically occluded coronary artery, the physiology of the chronic total occlusion (CTO) vessel and dependent microvasculature does not normalise immediately but improves significantly over time. Generally, there is an increase in fractional flow reserve (FFR) in the CTO artery, a decrease in collateral blood supply and an increase in FFR in the donor artery accompanied by an increase in blood flow and decrease in microvascular resistance in the myocardium supplied by the CTO vessel. Analogous to these physiological changes, positive remodelling of the distal CTO artery also occurs over time, and intravascular imaging can be helpful for analysing distal vessel parameters. Follow-up coronary angiography with physiological measurements after several weeks to months can be helpful and informative in a subset of patients in order to decide upon the necessity for treatment of residual coronary artery stenosis in the vessel distal to the CTO or in the contralateral donor artery, as well as in deciding whether stent optimisation is indicated. We suggest that such physiological guidance of CTO procedures avoids unnecessary overtreatment during the initial procedure, guides interventions at follow-up, and improves our understanding of what PCI in CTO means.

Distal pancreas-coeliac axis resection with preoperative selective embolization of the coeliac axis: a single high-volume centre experience.

Patients with ductal adenocarcinoma in the body and/or tail of the pancreas with involvement of the common hepatic artery and/or celiac axis have until recently been considered unresectable. In selected cases, distal pancreatectomy (DP) with en bloc celiac axis resection (DP-CAR) may be an option to achieve R0 resection. Patients with tumours in the body and/or tail of the pancreas locally advanced with involvement of the common hepatic artery and/or celiac axis, with no distant metastases, were evaluated for DP-CAR procedures. Preoperative embolization was performed 10-14days prior to surgery to enhance collateral arterial supply for the liver and stomach. A total of 21 patients went through DP-CAR of whom 15 were preoperatively embolized. R0 resection vas achieved in 76% of the patients comparable to our standard distal pancreatectomies. The DP-CAR patients had a significant longer postoperative hospital stay, but no difference in major complications, including pancreatic fistulas compared with our standard distal pancreatectomies. No 30 nor 90days postoperative mortality were recorded. Median survival in patients who underwent DP and DP-CAR procedures was 24.0 and 23.5months, respectively (P > 0.5). Outcomes after DP-CAR are comparable to standard distal pancreatectomies. DP-CAR after preoperative embolization is feasible and may in selected patients be a good option for treating patients with tumours in the body and/or tail of the pancreas with central arterial involvement.

Automatic collateral circulation scoring in ischemic stroke using 4D CT angiography with low-rank and sparse matrix decomposition.

Sufficient collateral blood supply is crucial for favorable outcomes with endovascular treatment. The current practice of collateral scoring relies on visual inspection and thus can suffer from inter and intra-rater inconsistency. We present a robust and automatic method to score cerebral collateral blood supply to aid ischemic stroke treatment decision making. The developed method is based on 4D dynamic CT angiography (CTA) and the ASPECTS scoring protocol. The proposed method, ACCESS (Automatic Collateral Circulation Evaluation in iSchemic Stroke), estimates a target patient's unfilled cerebrovasculature in contrast-enhanced CTA using the lack of contrast agent due to clotting. To do so, the fast robust matrix completion algorithm with in-face extended Frank-Wolfe optimization is applied on a cohort of healthy subjects and a target patient, to model the patient's unfilled vessels and the estimated full vasculature as sparse and low-rank components, respectively. The collateral score is computed as the ratio of the unfilled vessels to the full vasculature, mimicking existing clinical protocols. ACCESS was tested with 46 stroke patients and obtained an overall accuracy of 84.78%. The optimal threshold selection was evaluated using a receiver operating characteristics curve with the leave-one-out approach, and a mean area under the curve of 85.39% was obtained. ACCESS automates collateral scoring to mitigate the shortcomings of the standard clinical practice. It is a robust approach, which resembles how radiologists score clinical scans, and can be used to help radiologists in clinical decisions of stroke treatment.

Hypoxic-Mediated Oxidative Stress Condition and Hydroxyapatite-Inducing Osteogenic Differentiation of Human Mesenchymal Stem Cells: A Mathematical Modeling Study.

Avascular necrosis (AVN) of the bones remains a major clinical challenge. Fractures in the talus, the scaphoid, and the neck of the femur are especially challenging to heal due to the low blood vessel network and the lack of collateral blood supply. These fractures are associated with high rates of nonunion and increased infections that require repeated operations. Conventional treatments by autografting or allografting bone replacement and synthetic bone implants have limitations, including the invasiveness of operative procedures, tissue supply insufficiency, and the risk of host rejection. The advancement in tissue engineering has revealed the potential of stem cells as restorative agents for bone injuries. The administration of mesenchymal stem cells (MSCs) into the talus, the scaphoid, and the neck of the femur could produce enhanced osteogenesis via the manipulation of MSC culture conditions. In this study, we used hydroxyapatite as the nanomaterial, and hypoxic milieu to enhance MSC differentiation capacity into the osteogenic lineage, allowing for more rapid and efficient bone cell replacement treatment. Our results demonstrate 1% oxygen and 12.5 μg/mL of hydroxyapatite (HAP) as the optimal conditions to incorporate the osteogenic medium for the osteogenic induction of MSCs. We also established a proof of concept that the addition of HAP and hypoxic conditions could augment the osteoinductive capacity of MSCs. We also developed an accurate mathematical model to support future bone cell replacement therapy.

Identification and quantitative analysis of branching networks of the posterior intercostal arteries.

Morphological and anatomical characteristics of the posterior intercostal arteries have revived interest in their branching networks. Collateral supply between intercostal spaces is extensive due to anastomoses, although the data about the quantitative description of the branching networks in the existing literature are rather limited. The presence of collateral network between branches of the posterior intercostal arteries has been studied on forty-three Thiel-embalmed human cadavers. A network-based approach has been used to quantify the measured vascular branching patterns. Connections between branches of the same or adjacent posterior intercostal artery were identified. The non-anastomosing branches coursing in the intercostal spaces were also observed and their abundance was higher in comparison to anastomosing vessels. A quantitative analysis of collateral branching networks has revealed the highest density of vessels located close to the costal angle and most of the anastomosing branches were found between the fourth and tenth intercostal space. Anastomoses within the same posterior intercostal artery were more frequent in higher intercostal spaces, whereas in the lower intercostal spaces more connections were established between neighboring intercostal arteries. Our results indicate that due to abundant collateral contribution the possibility to cause an ischemic injury is rather low unless there is considerable damage to the blood supply of the trunk or surgical complication leading to ischemia or necrosis. Analyzing the proper course of collateral contributions of the posterior intercostal arteries may support further directions regarding the safest place for percutaneous transthoracic interventions, thoracocentesis, and lung biopsy.

Collateral Eligibility of Corporate Debt in the Eurosystem

We study the plethora of implications of the Eurosystem collateral framework for corporate bonds. Using data on the evolving collateral eligibility list, we identify the first inclusion date of bonds and issuers. We find that increased supply and demand for pledgeable collateral following eligibility (a) increases activity in the securities lending market, (b) lowers eligible bonds yields, and (c) reduces the liquidity of newly issued bonds, whereas that of older bonds remains unaffected. Thus, corporate bond lending relaxes the constraint of limited collateral supply, thereby improving market cohesion and completeness.