Organized Thrombus Research Articles

Differential diagnosis and intervention for braid-like coronary artery – case series analysis based on intracoronary artery imaging

Abstract Background Case reports on braid-like coronary arteries, often diagnosed as Woven Coronary Artery, are accumulating. However, the diversity of manifestation of such lesions has caused great confusion. Methods Consecutive patients admitted to Fuwai hospital with braid-like lesions on coronary angiography (CAG) were included. Intracoronary optical coherence tomography (OCT) was performed to verify the lesion nature. Major cardiovascular events were recorded in 12 months when a control CAG was recommended. Results From January 2018 to June 2019, braid-like lesions were identified in 6 patients (5 male) with average age of 45.3 years. All patients were transferred from lower-level hospitals. Five patients were current heavy smokers, and 4 patients had an old anterior myocardial infarction history. The braid-like segments were found in right coronary artery of 4 patients and in left anterior descending artery of the other 2 patients. Of these 6 braid-like lesions, 3 were culprit of coronary adverse events, and the other 3 lacked relevant history or documented inducible ischemia. The OCT images of all lesions were consistent with recanalization of organized thrombi, which consisted of septa that divided the lumen into multiple small cavities communicating with each other with significant stenosis. These structures had smooth inner borders with traces of intraluminal thrombi, but no separate 3-layered structure could be defined. Drug eluting stents were successfully implanted in all braid-like lesions. All patients were event free for 12 months, and 3 patients received control CAGs which showed stents patent. Conclusions Most cases of braid-like coronary artery may be recanalization of organized thrombi rather than Woven Coronary Artery. Smoking may be a potential risk factor. Percutaneous stent implantation may be challenging but benificial in selected patients. The underlying cause of the forming of such thrombotic lesions remained unclear. Imagings before and after intervention Funding Acknowledgement Type of funding source: None

Dating thrombus organization with eosinophil counts in deep venous thrombosis

ObjectiveIt is known that eosinophils (EOS) are essential for thrombus formation. Studies have demonstrated the association of EOS with coronary artery disease, stent thrombosis, coronary collateral development, and vasospastic angina. However, there is little data about the association of hemogram parameters, especially EOS counts, with deep venous thrombosis (DVT) subgroups. MethodsThe present study comprised 243 patients diagnosed with DVT (of whom 86 were acute, 72 were indeterminate, and 85 were chronic) and 75 control patients. Medical records of all the patients were reviewed, and relevant data were collected retrospectively. The baseline characteristics, as well as hemogram and biochemistry parameters, were recorded. ResultsThe patients with DVT had significantly lower median EOS count yet higher median neutrophil to lymphocyte ratio (NLR) than those of control patients (P < .001). Similarly, acute DVT patients had lower EOS count yet higher NLR values compared with those of indeterminate and chronic DVT patients. However, EOS count was not significantly different between chronic DVT and control groups. While NLR ratio was significantly correlated with acute DVT (r = 0.34; P < .001), Spearman's correlation test revealed that EOS count was inversely correlated with the presence of acute DVT (r = –0.52; P < .001). ConclusionsLow EOS count may lead the physician to a higher probability of acute DVT rather than indeterminate and chronic DVT.

Chronic thromboembolic pulmonary hypertension - still evolving.

Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the leading causes of severe pulmonary hypertension (PH). The disease is still underdiagnosed, and the true prevalence is unknown. CTEPH is characterized by intraluminal non-resolving thrombus organization and fibrous stenosis, or complete obliteration of pulmonary arteries, promoted by progressive remodeling of the pulmonary vasculature. One consequence of this is an increase in pulmonary vascular resistance and pressure, resulting in PH and progressive right heart failure, leading to death if left untreated.Endovascular disobliteration by pulmonary endarterectomy (PEA) is the preferred treatment for CTEPH patients. PEA surgery is the only technique that can potentially cure CTEPH disease, especially in patients with fresh or organized thrombi of the proximal branches of pulmonary arteries. However, not all patients are eligible for PEA surgery. Recent research has provided evidence suggesting balloon pulmonary angioplasty (BPA) and targeted medical therapy as additional promising available treatments options for inoperable CTEPH and recurrent/persistent PH after PEA surgery.Studies on BPA have shown it to improve pulmonary hemodynamics, symptoms, exercise capacity and RV function in inoperable CTEPH. Subsequently, BPA has developed into an essential component of the modern era of CTEPH treatment. Large randomized controlled trials have demonstrated varying significant improvements with targeted medical therapy in technically inoperable CTEPH patients. Thus, treatment of CTEPH requires a comprehensive multidisciplinary assessment, including an experienced PEA surgeon, PH specialist, BPA interventionist and CTEPH-trained radiologist at expert centers. In this comprehensive review, we address the latest developments in the fast-evolving field of CTEPH. These include advancements in imaging modalities and developments in operative and interventional techniques, which have widened the range of patients who may benefit from these procedures. The efficacy and safety of targeted medical therapies in CTEPH patients are also discussed. As the treatment options for CTEPH improve, hybrid management involving multiple treatments in the same patient may become a viable option in the near future.

Riociguat in the Treatment of Chronic Thromboembolic Pulmonary Hypertension: An Evidence-Based Review of Its Place in Therapy.

Chronic thromboembolic pulmonary hypertension (CTEPH) is classified as group-4 pulmonary hypertension caused by organized thrombi in pulmonary arteries and vasculopathy in nonoccluded areas leading to right heart failure and death. In addition to chronic anticoagulation therapy, each patient with CTEPH should receive treatment assessment starting with evaluation for pulmonary endarterectomy (PEA), which is the guideline recommended treatment. There is increasing experience with balloon pulmonary angioplasty (BPA) for inoperable patients; this option, like PEA, is reserved for specialized centers with expertise in this treatment method. Inoperable patients are candidates for targeted drug therapy. Riociguat remains the only approved medical therapy for CTEPH patients deemed inoperable or with persistent pulmonary hypertension after PEA. The role of riociguat therapy preoperatively or in tandem with BPA is currently under investigation. The purpose of this review is to evaluate the safety and efficacy of riociguat in the treatment of CTEPH.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: State of the art.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance, ultimately triggering progressive right heart failure and death. Currently, its exact mechanism is not fully understood. Pulmonary endarterectomy (PEA) has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions. Nevertheless, 37% of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors, and nearly half of the operated patients have residual or recurrent pulmonary hypertension. Riociguat is the only approved drug for CTEPH, although its effect is limited. Balloon pulmonary angioplasty (BPA) is a promising alternative treatment for patients with CTEPH. After more than 30 years of development and refinements, emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension, with acceptable complications and comparable long-term prognosis to PEA. This review summarizes the pathophysiology of CTEPH, BPA history and development, therapeutic principles, indications and contraindications, interventional procedures, imaging modalities, efficacy and prognosis, complications and management, bridging and hybrid therapies, ongoing clinical trials and future prospects.

Myocardial ischemia due to a recanalized chronic coronary thrombus: Angiographic and optical coherence tomography imaging insights.

Chronic organized thrombus as a result of prior untreated myocardial infarction can determine myocardial ischemia. This entity appears as an angiographically irregular and hazy image; optical coherence tomography is useful to evaluate these ambiguous lesions and guide interventional treatment.

Preclinical evaluation of an endovascular sealing device for distal re-entry tears in type B aortic dissection in a porcine model

ObjectivesThe objective of present study was to evaluate the feasibility and safety of a novel endovascular sealing device for distal re-entry tears in type B aortic dissection in a porcine model. BackgroundDistal re-entry tears are a well-recognized risk factor for unfavorable aortic remodeling after thoracic endovascular aortic repair. However, there is currently no device for sealing a distal re-entry tear. MethodsWe implanted the ENDOPATCH device (Weiqiang Medical, Hangzhou, China) in 15 pigs (40–50 kg) under angiographic guidance. The device can be retrieved and repositioned with an 8–10 French sheath. All pigs were assessed using angiography before sacrifice 1- (n = 1), 3- (n = 1), and 6 months (n = 13) after implantation, which was followed by gross specimen evaluation and histological examination of harvested tissues. ResultsThe ENDOPATCH device was successfully implanted in all 15 pigs. The mean disk diameter of the implant was 10.3 ± 1.7 mm, and the chosen device was 4.4 ± 0.9 mm larger than the measured maximum diameter of the fistula. No device migration or leakage was observed angiographically, before sacrifice. An organized thrombus on the disk surface was found in the inferior vena cava of one pig. Complete sealing of the fistula was confirmed by gross and microscopic examinations in all pigs. ConclusionsOur results indicated that the ENDOPATCH device is feasible and safe in a porcine model. Human studies are needed to evaluate the safety and efficacy of the ENDOPATCH.

Targeted Angiogenesis Gene Expression Profiling of Patients with Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by organized thrombi in the pulmonary arteries leading to right heart failure and death. Impaired angiogenesis and systemic inflammation could be involved in the pathophysiology of this disease. The aim of this study was to determine the angiogenic expression profile in patients with CTEPH. We studied pulmonary endarterectomy specimens from 5 CTEPH patients, distal pulmonary arteries specimens from 5 CTEPH patients undergoing transplantation (CTEPH TP) and distal pulmonary arteries specimens from 5 controls undergoing lobectomy for low-stage cancer without metastasis enrolled at Marie Lannelongue Hospital. We also analyzed Pulmonary endothelial cells (PECs) isolated by enzymatic digestion from all subjects, comparing them to PECs from patients with idiopathic pulmonary hypertension (iPAH). Angiogenic proteomic profiling of specimens and PECs was performed using Human angiogenesis qPCR array from Anygenes according to manufacturer instructions (198 biomarkers). Gene expression analyses revealed that several angiogenic molecules (such as VEGFA) and receptors (such as VEGFR2) are decreased in fibrotic CTEPH thrombi (CTEPH) and to a greater extent in distal pulmonary arteries specimen (CTEPH TP) as compared to controls (Figure 1A). Endothelial cells isolated from thrombi (CTEPH) and distal pulmonary arteries specimen (CTEPH TP) have distinct angiogenic profiles from iPAH and controls (Figure 1B). These results suggest a downregulation of angiogenesis in endothelial cells from patients with CTEPH as compared to controls. Downregulation of genes involved in angiogenesis and dysfunctional PECs in CTEPH thrombi may underlie thrombus persistence.

Comparison of Aneurysm Patency and Mural Inflammation in an Arterial Rabbit Sidewall and Bifurcation Aneurysm Model under Consideration of Different Wall Conditions.

Background: Biological processes that lead to aneurysm formation, growth and rupture are insufficiently understood. Vessel wall inflammation and degeneration are suggested to be the driving factors. In this study, we aimed to investigate the natural course of vital (non-decellularized) and decellularized aneurysms in a rabbit sidewall and bifurcation model. Methods: Arterial pouches were sutured end-to-side on the carotid artery of New Zealand White rabbits (vital [n = 6] or decellularized [n = 6]), and into an end-to-side common carotid artery bifurcation (vital [n = 6] and decellularized [n = 6]). Patency was confirmed by fluorescence angiography. After 28 days, all animals underwent magnetic resonance and fluorescence angiography followed by aneurysm harvesting for macroscopic and histological evaluation. Results: None of the aneurysms ruptured during follow-up. All sidewall aneurysms thrombosed with histological inferior thrombus organization observed in decellularized compared to vital aneurysms. In the bifurcation model, half of all decellularized aneurysms thrombosed whereas the non-decellularized aneurysms remained patent with relevant increase in size compared to baseline. Conclusions: Poor thrombus organization in decellularized sidewall aneurysms confirmed the important role of mural cells in aneurysm healing after thrombus formation. Several factors such as restriction by neck tissue, small dimensions and hemodynamics may have prevented aneurysm growth despite pronounced inflammation in decellularized aneurysms. In the bifurcation model, rarefication of mural cells did not increase the risk of aneurysm growth but tendency to spontaneous thrombosis.

Pulmonary Embolectomy for Acute Pulmonary Embolism: A Word of Caution.

Pulmonary embolectomy is an effective treatment of acute pulmonary embolism (APE) but not for chronic pulmonary thromboembolism. We described surgical experience of two patients with APE in preexistent unidentified chronic pulmonary thromboembolism. One patient who presented with severe hypoxia but stable hemodynamics underwent successful pulmonary endarterectomy for proximal organized thrombus instead of pulmonary embolectomy. The other patient who required extracorporeal membrane oxygenation for severe hypoxia developed right heart failure because of residual distal organized thrombus after pulmonary embolectomy. Clinical and radiographical presentation of APE in chronic pulmonary thromboembolism mimics APE, and thus, candidates of pulmonary embolectomy should be carefully selected.

Chordae Willisii Within the Transverse Sinus: Morphologic Study

Some have suggested that trabeculae within the transverse sinuses (chordae Willisii) might restrict flow and potentially contribute to thrombus organization. In addition, these structures might be encountered with endovascular procedures within the transverse sinus and are now readily seen on imaging. Therefore as anatomic studies of these structures are scant, the current study aimed to better elucidate these structures within the transverse sinus via a morphologic study in cadavers. Thirty fresh-frozen, cadaveric transverse sinuses were dissected, and their detailed morphology was recorded. Classification schemes were applied based on the anatomy and orientation of each chordae. Chordae were found on 70% of sides and were statistically more likely to be found on right sides (86.6%) (P < 0.01). Three types and 3 classes of chordae were identified. There was a statistically significant difference between sides regarding type of chordae (P= 0.02). To date, a comprehensive anatomic evaluation of the intraluminal chordae of the transverse sinuses has been lacking. Knowledge of these bands is also essential to those performing endovascular procedures of the dural venous sinuses and for those interpreting imaging of these structures.

Feasibility of shear wave sonoelastography to detect endoleak and evaluate thrombus organization after endovascular repair of abdominal aortic aneurysm

To investigate the feasibility of shear wave sonoelastography (SWS) for endoleak detection and thrombus characterization of abdominal aortic aneurysm (AAA) after endovascular repair (EVAR). Participants who underwent EVAR were prospectively recruited between November 2014 and March 2016 and followed until March 2019. Elasticity maps of AAA were computed using SWS and compared to computed tomography angiography (CTA) and color Doppler ultrasound (CDUS). Two readers, blinded to the CTA and CDUS results, reviewed elasticity maps and B-mode images to detect endoleaks. Three or more CTAs per participant were analyzed: pre-EVAR, baseline post-EVAR, and follow-ups. The primary endpoint was endoleak detection. Secondary endpoints included correlation between total thrombus elasticity, proportion of fresh thrombus, and aneurysm growth between baseline and reference CTAs. A 3-year follow-up was made to detect missed endoleaks, EVAR complication, and mortality. Data analyses included Cohen's kappa; sensitivity, specificity, and positive predictive value (PPV); Pearson coefficient; and Student's t tests. Seven endoleaks in 28 participants were detected by the two SWS readers (k = 0.858). Sensitivity of endoleak detection with SWS was 100%; specificity and PPV averaged 67% and 50%, respectively. CDUS sensitivity was estimated at 43%. Aneurysm growth was significantly greater in the endoleak group compared to sealed AAAs. No correlation between growth and thrombus elasticity or proportion of fresh thrombus in AAAs was found. No new endoleaks were observed in participants with SWS negative studies. SWS has the potential to detect endoleaks in AAA after EVAR with comparable sensitivity to CTA and superior sensitivity to CDUS. • Dynamic elastography with shear wave sonoelastography (SWS) detected 100% of endoleaks in abdominal aortic aneurysm (AAA) follow-up that were identified by a combination of CT angiography (CTA) and color Doppler ultrasound (CDUS). • Based on elasticity maps, SWS differentiated endoleaks from thrombi within the aneurysm sac (p < 0.001). • After 3-year follow-up, no new endoleaks were observed in SWS negative examinations.

GADOLINIUM CONTRAST BALLOON PULMONARY ANGIOPLASTY FOR A PATIENT WITH CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION AND SEVERE IODINE ALLERGY

Chronic thromboembolic pulmonary hypertension (CTEPH) is group 4 pulmonary hypertension caused by organized thrombi in pulmonary arteries. Balloon pulmonary angioplasty (BPA) is a treatment option for patients with inoperable CTEPH but needs contrast media. A 61-year-old female presented with

Abstract TP214: 3D-Electron Microscopy for the Analysis of the Microstructure of Acute Ischemic Stroke Clots

Introduction: Characterization of acute ischemic stroke thrombi has typically focused on the two dimensional (2D) histological characterization of the thrombus. Little is known about the three dimensional (3D) structure of these occlusive thrombi. Electron Microscopy (EM) can be used to obtain 3D information about the organization of clot components. Individual structures can be segmented and qualitative and quantitative information obtained from the clots. Methods: Following IRB approval from Mayo Clinic, acute ischemic stroke clot samples were collected from 10 patients treated at Mayo Clinic. Samples were immediately fixed in fresh modified Trumps fixative solution. A representative fragment of clot was taken and split longitudinally into two pieces; one piece was sent for 3D-EM analysis and the other for histological processing and analysis. Hematoxylin and eosin stain (H&amp;E) and Martius Scarlett Blue (MSB) histological stains were used for conventional histopathology evaluation and components analysis. Immunohistochemical (IHC) staining using anti-CD42b (Platelets) was applied to confirm the presence of platelets in each clot. Serial block-face scanning electron microscopy was used to generate high-resolution three-dimensional images. Results: The 2D morphological features of the clot were identified using H&amp;E, MSB and anti-CD42b staining. The 3D organization of thrombi varies greatly, both within and between clots depending on the constituents. Red Blood Cell-rich areas are mainly composed of Red Blood Cells packaged tightly together, with a small number of Fibrin strands interwoven between the cells. Fibrin-rich areas are characterized by dense networks of fibrin strands along with platelets and White Blood Cells with some sparse Red Blood Cells present. Platelet-rich areas are composed of large volumes of de-granulated platelets, some fibrin stands and white blood cells and an absence of Red Blood Cells. Conclusions: 3D electron microscopy can provide important information on the organization of components within thrombi. This could provide key information on the age and etiology of the thrombus. In addition, it may help to inform thrombolytic treatment and medical device design.

Very late coronary thrombosis following bioresorobable vascular scaffold implantation for spontaneous coronary artery dissection

Abstarct: We present a case of acute coronary syndrome 6 years after successful bioresorbable vascular scaffold (BVS) implantation for right coronary artery spontaneous coronary artery dissection (SCAD). OCT demonstrated neoatherosclerotic intermediate lesion with organized thrombus, whereas fractional flow reserve documented hemodynamically significant lesion at the place of previous BVS.

Localization of focus by 18 F-fludeoxyglucose positron emission tomography computed tomography in the definitive diagnosis of infective endocarditis

18 F-fludeoxyglucose positron-emission tomography computed tomography scans are helpful in making definitive diagnosis of infective endocarditis (IE) in some selected cases. We are reporting two cases of IE, in one case, the infective focus was in the organized left ventricular mural thrombus and the second case the infective focus was found in the aortic root and annulus and the prosthetic valve was spared. This being a noninvasive test can be repeated to ascertain the adequacy of treatment during follow-up.

Компенсаторні механізми при венозному тромбозі дурального синуса. Клінічний випадок

SummaryPatients with cerebral venous thrombosis (CVT) present with range of symptoms,which vary widely from headache to coma. Chronic occlusion of venous dural sinusesleads to the initiation of compensation processes, such as vascular collateralization,recanalization of the organized thrombus. Consequently, their efficacy determinesdisease course and severity.The aim of our study was to highlight the clinical challenges, while managing apatient with subcompensated CVT. Taking into account the fact that mild severity isobserved in 20% of cases, eventually about a quarter of patients presenting withheadache of unclear etiology becomes unnoticed and results with their quality of life atlow level.To analyze the disease outcome and prognosis, we accurately studied compensationmechanisms, which occur in patient due to dural sinus thrombosis, notably venouscollateral circulation and thrombus recanalization. However, the most important«pitfall» of chronic dural sinuses occlusion, when not appropriately treated, is the factthat hemodynamic compensation also leads to high risk of cerebrovascular events,which may lead to death or disability.We presented the patient with cerebral venous thrombosis of the transverse andsigmoid sinuses manifested migraine-like headache with a vegetative issue and signs ofincreased intracranial pressure.162Due to the absence of anticoagulant therapy, venous drainage through collateralpathways and recanalization of thrombosed sinuses were insufficient to maintaincerebral blood supply, resulting in the diffuse cerebral edema as well as secondarybrain injury. After an accurate survey, diagnostic procedures, prescribing ofindividualized treatment and long-term follow-up with correction of therapy the patientexperienced regression of CVT symptoms.Cerebral magnetic resonance imaging venography is an important tool for thediagnosis and predictiction of prognosis of this condition. Thus, patients with a longhistory of untreatable headache and signs of intracranial hypertension should undergothis procedure. To consider intracranial vascular events and outcome, the evaluation ofvenous hemodynamics should be conducted. Moreover, it is often necessary to examinecerebral veins and sinuses, when hemorrhagic stroke does not correspond to cerebralarterial territories and has unclear etiology.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is classified as Group-4 pulmonary hypertension caused by organized thrombi in pulmonary arteries. Pulmonary endarterectomy (PEA) has been shown to improve the symptoms and prognoses of patients with proximal CTEPH. The soluble guanylate cyclase stimulator (riociguat) is the sole FDA-licensed drug for the treatment of CTEPH, and guidelines recommend its use for patients with inoperable CTEPH or residual or recurrent pulmonary hypertension following PEA. Balloon pulmonary angioplasty (BPA) is a new procedure, but it is a promising alternative to PEA, especially in patients with inoperable CTEPH. This review summarizes the history, indications, procedures and complications of BPA. Finally, we discuss the future perspective of BPA for better management of CTEPH.

PAPILLARY ENDOTHELIAL HYPERPLASIA—A CASE REPORT OF THIS RARE VASCULAR LESION

We will report a case of intravascular papillary endothelial hyperplasia, an unusual blood vessel disease occurring in the oral cavity. A female patient, 54 years of age, showed a bluish asymptomatic nodule in the lower lip, measuring 5 mm in diameter. The clinical diagnostic hypotheses were hemangioma or mucocele. An excisional biopsy was performed. The histopathologic examination demonstrated papillary tufts with a central hyaline core lined by a single layer of endothelial cells, which were positive for CD31 staining. The final diagnosis was papillary endothelial hyperplasia. This is a benign reactive vascular lesion with uncertain etiology. Scientific studies report this lesion as an organized thrombus. The treatment performed was surgical with a good prognosis. The 1-year follow-up period showed no signs of clinical recurrence.

Comparative Study of Hemodynamics and Pathological Consequences of Saccular Versus Fusiform Experimental Aortic Aneurysms

Introduction - Saccular aneurysms are thought to have a worst evolution than fusiform aneurysms in humans, probably for hemodynamic reasons (1,2). Some authors advocate earlier aggressive therapy towards saccular aneurysms to prevent death from rupture (3). However, data is lacking regarding comparison of saccular versus fusiform aneurysms. The aim of this study was to compare the differential hemodynamics and pathological consequences of fusiform versus saccular aneurysms in rats. Methods - Forty Lewis rats, at 9 weeks of age, were prospectively randomized in two groups of twenty individuals each: “saccular” (Group A) and “fusiform” groups (Group B). Decellularized thoracic aortas from guinea pigs were xenografted to the abdominal aorta in either an end-to-end (fusiform) or side-to-end (saccular) anastomosis manner (4). Main objective was to evaluate hemodynamic outcomes through duplex-scan and magnetic resonance imaging (MRI), one week and three weeks after surgery. Rats were sacrificed 4 weeks after surgery in order to analyze aneurysms histology, dosage of matrix metallopeptidase-9 (MMP-9)/matrix metallopeptidase-2 (MMP-2), plasmin/anti-plasmin complex in the plasma and in conditioned media. Results - All rats displayed a patent aortic aneurysm at one and three weeks. At three weeks, duplex-scan showed a mean growth of 34.7±9.1 % in group A, compared to the first week. Similar results were found in group B with a mean growth of 33.2±9.8 % (p=not significant). A complete flow recirculation was found in saccular aneurysms unlike fusiform aneurysms where recirculation was incomplete (persistent longitudinal flow). These results were confirmed by MRI examination. Corresponding histology showed an organized intraluminal thrombus (ILT) as a background cup in group A whereas it was partially developed on one side in group B (Figure 1). The ILT from saccular aneurysms was enriched in iron coming from lysis of Red Blood Cells as compared to fusiform aneurysms. Similarly, calcifications were more important in group A as compared to group B, corresponding to more tissue retention of free DNA, potentially released by dying neutrophils. Conclusion - Saccular and fusiform aneurysms show a similar growth over time but differential specific hemodynamics impact the form, the aspect and the biology of ILT in each type of aneurysm. In particular, ILT remains more active in saccular aneurysms whereas fusiform aneurysms display a healing process through fibrosis. The active ILT in saccular aneurysms maintain an inflammatory environment by recruiting neutrophils and might be a risk factor to their worst evolution in time compared to fusiform aneurysms.