Sonothrombolysis with an acoustic net-assisted boiling histotripsy: A proof-of-concept study.

Whilst sonothrombolysis is a promising and noninvasive ultrasound technique for treating blood clots, bleeding caused by thrombolytic agents used for dissolving clots and potential obstruction of blood flow by detached clots (i.e., embolus) are the major limitations of the current approach. In the present study, a new sonothrombolysis method is proposed for treating embolus without the use of thrombolytic drugs. Our proposed method involves (a) generating a spatially localised acoustic radiation force in a blood vessel against the blood flow to trap moving blood clots (i.e., generation of an acoustic net), (b) producing acoustic cavitation to mechanically destroy the trapped embolus, and (c) acoustically monitoring the trapping and mechanical fractionation processes. Three different ultrasound transducers with different purposes were employed in the proposed method: (1) 1-MHz dual focused ultrasound (dFUS) transducers for capturing moving blood clots, (2) a 2-MHz High Intensity Focused Ultrasound (HIFU) source for fractionating blood clots and (3) a passive acoustic emission detector with broad bandwidth (10 kHz to 20 MHz) for receiving and analysing acoustic waves scattered from a trapped embolus and acoustic cavitation. To demonstrate the feasibility of the proposed method, in vitro experiments with an optically transparent blood vessel-mimicking phantom filled with a blood mimicking fluid and a blood clot (1.2 to 5 mm in diameter) were performed with varying the dFUS and HIFU exposure conditions under various flow conditions (from 1.77 to 6.19 cm/s). A high-speed camera was used to observe the production of acoustic fields, acoustic cavitation formation and blood clot fragmentation within a blood vessel by the proposed method. Numerical simulations of acoustic and temperature fields generated under a given exposure condition were also conducted to further interpret experimental results on the proposed sonothrombolysis. Our results clearly showed that fringe pattern-like acoustic pressure fields (fringe width of 1 mm) produced in a blood vessel by the dFUS captured an embolus (1.2 to 5 mm in diameter) at the flow velocity up to 6.19 cm/s. This was likely to be due to the greater magnitude of the dFUS-induced acoustic radiation force exerted on an embolus in the opposite direction to the flow in a blood vessel than that of the drag force produced by the flow. The acoustically trapped embolus was then mechanically destructed into small pieces of debris (18 to 60 µm sized residual fragments) by the HIFU-induced strong cavitation without damaging the blood vessel walls. We also observed that acoustic emissions emitted from a blood clot captured by the dFUS and cavitation produced by the HIFU were clearly distinguished in the frequency domain. Taken together, these results can suggest that our proposed sonothrombolysis method could be used as a promising tool for treating thrombosis and embolism through capturing and destroying blood clots effectively.

Acute Occlusion of the Abdominal Aorta Associated with Left Ventricular Thrombus: A Case Report.

BACKGROUND Acute aortic occlusion (AAO) is a rare emergency with high mortality. The typical clinical presentation is the sudden appearance of pain, paralysis, sensory disturbances, and mottling of the lower extremities. The etiology of AAO can be broadly classified into 3 categories: in situ thrombosis, arterial embolism, and occlusion of grafts. AAO is a rare consequence of myocardial infarction in the era of anticoagulation therapy, as part of the management of acute coronary syndrome (ACS). CASE REPORT We report the case of a 65-year-old woman who presented with acute lower extremity pain and weakness after a myocardial infarction 2 weeks earlier. She was on standardized antiplatelet therapy, a high blood D-dimer level was found during a visit to the Emergency Department, a left ventricular mural thrombus was detected using bedside ultrasound, and computed tomography angiography revealed thrombotic occlusion of the abdominal aorta. AAO disease was diagnosed, but the patient refused further treatment and died after 7 days of follow-up. CONCLUSIONS In recent years, anticoagulation has become part of the standard of care for patients with myocardial infarction or atrial fibrillation, which has led to a lower incidence of arterial embolism leading to AAO than in situ thrombosis. Depending on the type of occlusion, there are also differences in the surgical approach. A computed tomography angiography of the abdomen should be performed on all patients in whom AAO cannot be ruled out. Timely diagnosis and prompt surgical intervention are essential to preventing mortality.

Early warm compress treatment can promote recanalization of vascular embolisms and reduce tissue necrosis after polymethyl methacrylate injection.

Injection of fillers for soft tissue augmentation can lead to a variety of complications, among which vascular occlusion caused by intravascular injection of filler will induce severe or permanent damage. The treatment strategies for intravascular embolization caused by injection include warm compress application, but the exact beneficial effects of this therapy have not been confirmed. The purpose of this study is to construct an intravascular injection embolism model and observe the effectiveness of warm and cold compress through a randomized, controlled trial. Thirty rabbit's sixty ears were randomly divided into warm compress group, cold compress group, and control group. Polymethyl methacrylate (PMMA) was slowly injected into the central ear artery (CEA) to cause vascular embolism. Warm compress and cold compress treatment were performed respectively. The vascular recanalization and other related indexes were observed at 30 min, 1 day, and 7 days after injection, and the tissue necrosis was analyzed at 7 days. In the early stage of vascular embolization, warm compress can immediately promote vascular dilatation, blood circulation and partial blood flow recovery. One day after intravascular injection, warm compress can reduce intravascular embolization and reduce the incidence of tissue necrosis. At 7 days after intravascular injection, the vessels in the cold compress and control groups were still embolized while the percentage of recanalization in the warm compress group was 47.4% (P < 0.000). Early-stage warm compress after intravascular PMMA injection is conducive to recanalization of vascular embolization and reducing tissue necrosis.

Thromboaspiration of Abdominal Aortic Mural Thrombus: A New Endovascular Approach.

Primary aortic mural thrombus (PAMT) is defined as a thrombus attached to the aortic wall in the absence of any atherosclerotic or aneurysmal disease in the aorta and a cardiac source of embolus. There is no consensus on the ideal treatment of PAMT. There are a few reports of thromboaspiration of aortic thrombus in literature. The objective of this article is to report a new endovascular approach of abdominal aortic mural thrombus. The use of Penumbra Thromboaspiration System is a feasible procedure to treat abdominal aortic thrombus and may be an option for patients unsuitable for open repair or conservative treatment.

Cholesterol crystal embolism in multiple organs after transarterial chemoembolization for hepatocellular carcinoma: An autopsy case report.

RATIONALE: Transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) rarely causes cholesterol crystal embolism (CCE). In our case, the histological findings suggested that the onset of CCE occurred at different time points in different organs. PATIENT CONCERNS: A 72-year-old Japanese woman with HCC underwent TACE. After TACE, serum creatinine level and eosinophil count gradually increased. Three months later, she was admitted to our department with a fever and back pain. DIAGNOSIS: Laboratory examinations showed sepsis with disseminated intravascular coagulation. She was treated with antimicrobial agents and anticoagulants, but died of multiple organ failure. INTERVENTIONS: An autopsy was performed to examine the cause of multiple organ failure after 3 months of TACE. OUTCOMES: A mixture of both chronic phase emboli with intimal thickening and fibrosis and acute phase emboli with inflammatory cell infiltration were observed in the small intestine. Moreover, multiple intravascular cholesterol fissures were observed in the kidney, stomach, duodenum, colon, pancreas, and spleen, which were the vascular dominant organs of the celiac artery and superior mesenteric artery. These histological findings suggested that cholesterol crystals were continuously disseminated after TACE. LESSONS: TACE for HCC may cause progressive CCE and damage in multiple organs. When progressive renal dysfunction, eosinophilia, or multiple organ dysfunction is observed after TACE, the CCE should be suspected.

Management Strategies for Descending Thoracic Aortic Thrombus: A Review of the Literature.

Descending thoracic aortic thrombus (DTAT) is an under-recognized source of systemic emboli with potential catastrophic consequences. Imaging modalities such as echocardiography, computed tomography, magnetic resonance imaging, and angiography can help identify and characterize the extent of embolic events. Established guidelines regarding the management of DTAT are currently lacking. Multiple treatment modalities are available; however, the effectiveness of each approach remains to be determined. In this study, we performed a review to examine the clinical presentation, diagnostic methods and findings, and outcomes of various treatment options for patients with DTAT. Medical management is the least invasive and most frequently chosen initial approach, offering a high reported success rate, whereas endovascular therapy can have a role in thrombus exclusion should conservative management fail.

[Endocarditis complicated by anterior myocardial infarction: a case report. What the guidelines do not say]. / Endocardite infettiva complicata da infarto anteriore: un caso clinico. Quello che le linee guida non dicono.

Acute myocardial infarction is an uncommon complication of infective endocarditis, burdened by high mortality and often underdiagnosed. Due to its reduced frequency, current guidelines do not always highlight this condition or provide clear indications regarding treatment. We present a case of acute coronary syndrome induced by the occlusion of the anterior descending artery, due to a septic embolus and treated by aspiration of the embolic material. The clinical-instrumental aspects necessary to raise the suspicion of endocarditis and make the diagnosis are then examined. Subsequently, all the possible therapeutic strategies and any complications of the traditional treatment of acute coronary syndromes during infectious valve disease are analyzed. Since clinical presentation may be extremely variable, the establishment of a multidisciplinary team would allow, in these cases, a more appropriate and complete diagnostic and therapeutic management.

Cardiac metastasis causes paradoxical malignant embolism.

BACKGROUND: Embolic events play an important role in clinical everyday practice. Malignant arterial embolism is a rare nevertheless often fatal entity for cardiac, cerebral or systemic ischemia, requiring immediate diagnosis and treatment. CASE: This is a case report of a 65 years-old female, suffering from pulmonal adenocarcinoma, who was hospitalized due to neurological deficits caused by an acute ischemic stroke, followed by anterior myocardial infarction within 3 days. Diagnostic work-up revealed metastasis of the pulmonal adenocarcinoma in the right atrium and a patent foramen ovale. Histopathological examination of the coronary embolus verified paradoxical arterial embolism of the pulmonal adenocarcinoma into a coronary vessel and consequently cerebral arteries. CONCLUSION: The present case underlines the need for (i), consideration of malignant embolism, (ii) histopathological examination of the embolus to determine its etiology, and (iii) interdisciplinary discussion of individual therapeutic and prevention strategies in cancer patients with cerebral, cardiac or systemic embolic events.

Clinical Clues for the Current Diagnosis of Acute Lower Limb Ischemia: A Contemporary Case Series.

BACKGROUND: Acute lower limb ischemia (ALI) is a limb and life-threatening condition whose treatment largely depends on the underlying cause. The clinical distinction between the main causes may have changed over the years because of changes in the epidemiology of this syndrome. The objective of this study was to determine the clinical pattern associated with the main causes of ALI in a contemporary series of cases. METHODS: We retrospectively reviewed all consecutive ALI cases admitted to a tertiary hospital between 2007 and 2019. ALI secondary to other conditions than embolism or NAT were excluded. The association between clinical variables and the ALI cause was assessed with multiple logistic regressions and the discriminative power of the resulting clinical predictive scores with the area under the ROC curve. RESULTS: The study group included 243 patients (mean age 77.2 years; 52.7% male), of which 140 (57.6%) were caused by an arterial embolism and 103 (42.4%) by a NAT. Among these latter, 78 (75.7%) were related to an atherosclerotic NAT and 25 (24.3%) to a complicated popliteal aneurysm. Independent risk factors associated with embolism included atrial fibrillation (OR 10.26, 95% CI 5.1 - 20.67) or female gender (OR 5.44, 95% CI 2.76 - 10.71), but not the severity of the episode or the presence of contralateral pulses. Those related to a NAT included a previous symptomatic peripheral arterial disease (OR 2.68, 95% CI 1.35 - 5.35) and seeking consultation more than 24 hours after the beginning of symptoms (OR 2.57, 95% CI 1.32 - 5), but not a higher rate of other vascular risk factors. Among patients with NAT, previous intermittent claudication (OR 8.34, 95% CI 2.42 - 28.72) and >24 hs delay of arrival of the patient (OR 4.78, 95% CI 1.48 - 15.43) were more frequent among those related to an atherosclerotic NAT, whereas higher hemoglobin levels (OR 1.60, 95% CI 1.21 - 2.11) and non-significantly the history of tobacco smoking (OR 2.95, 95% CI 0.84 - 10.36) among those with a popliteal aneurysm-related NAT. The discriminative power of the two clinical models resulting from these predictive variables for differentiating embolism from NAT and atherosclerosis-related NAT from popliteal aneurysm-related NAT was excellent (0.86 and 0.85, respectively). CONCLUSION: Certain clinical features appear to be no longer useful in the distinction between embolism and NAT, while others may help in the differential diagnosis between atherosclerotic and popliteal aneurysm-related NAT. Surgeons must be aware of possible changes in the presentation of ALI because time constraints are frequent and clinical data remain essential.

Unexplained arterial thrombosis: approach to diagnosis and treatment.

Arterial thrombotic events in younger patients without a readily apparent etiology present significant diagnostic and management challenges. We present a structured approach to diagnosis with consideration of common causes, including atherosclerosis and embolism, as well as uncommon causes, including medications and substances, vascular and anatomic abnormalities, systemic disorders, and thrombophilias. We highlight areas of management that have evolved within the past 5 years, including the use of dual-pathway inhibition in atherosclerotic disease, antithrombotic therapy selection in embolic stroke of undetermined source and left ventricular thrombus, the role of closure of patent foramen ovale for secondary stroke prevention, and the thrombotic potential of coronavirus disease 2019 infection and vaccination. We conclude with a representative case to illustrate the application of the diagnostic framework and discuss the importance of consideration of bleeding risk and patient preference in determining the appropriate management plan.

Percutaneous Retrieval of Venous Bullet Embolism.

PURPOSE: Bullet fragment embolization is a rare but potentially fatal complication of traumatic gunshot injury. Herein, we present a case of a patient who demonstrated migration of a bullet fragment from the lower chest into the left common iliac vein. Continual identification of foreign bodies on trauma imaging is of the utmost importance. Identifying and treating this rare entity can help vascular interventionalists improve patient outcomes. CASE REPORT: Our patient presented to the emergency room after sustaining 2 gunshot wounds to the right axilla. Initial imaging demonstrated 2 bullet fragments: one in the right axilla and another in the lower chest overlying the heart. A subsequent trauma computed tomography was performed 13 minutes later and demonstrated a bullet fragment in the left common iliac vein, which had embolized from the original location in the lower chest. Interventional radiology was consulted to perform foreign body removal. A transcutaneous approach was utilized, and the bullet embolus was removed successfully without complication. CONCLUSION: Bullet fragment embolization is a rare entity with complications ranging from critical limb ischemia to venous thrombosis or obstruction. This case helps to demonstrate the importance of identifying and accounting for bullet fragments in gunshot trauma imaging.

Prosthetic Aortic Valve Thrombosis Complicated by Left Main Coronary Artery Bifurcation Embolism: Case Report and Review of Literature.

Coronary embolism due to prosthetic valve thrombosis is a rare cause of acute coronary syndrome. We report the challenging case of a 66-year-old female patient with non-ST-elevation myocardial infarction caused by left main coronary artery bifurcation embolism in the setting of mechanical aortic valve thrombosis. The patient was treated with intravenous thrombolysis. Four hours later, she suffered an anterior ST-elevation myocardial infarction due to left anterior descending artery embolization. Repeat coronary angiogram showed complete disappearance of the LMCA embolus with only distal LAD occlusion. The patient was further treated medically with excellent outcome.

Early Triage of Cardioembolic Sources Using Chest Spectral Computed Tomography in Acute Ischemic Stroke.

OBJECTIVES: The present study investigated the potential usefulness of delayed-phase, low-dose, non-gated, chest spectral CT scans (DSCT) for the early triage of cardioembolic (CE) sources in patients admitted with acute ischemic stroke (AIS), and for the simultaneous detection of myocardial disease and thrombotic complications. MATERIAL AND METHODS: Since July 2020 and promoted by the COVID-19 pandemic, we implemented the use of DSCT after cerebrovascular CT angiography (CTA) among patients with AIS using a dual-layer spectral CT. We explored the presence of CE sources, as well as late myocardium iodine enhancement (LIE) and pulmonary thromboembolism. Among patients further undergoing transesophageal echocardiogram (TEE) or cardiac CTA, we explored the diagnostic performance. RESULTS: Fifty consecutive patients with AIS who underwent DSCT after cerebrovascular CTA comprised the patient population. The confidence degree for excluding cardiac thrombi was significantly higher than for LIE (4.4±0.8 vs. 3.4±1.3, p<0.0001). DSCT identified a CE source in 4 (8%) and LIE in 24 (48%) patients. The iodine ratio of CE sources was significantly lower compared to the left atrial appendage of patients with no CE sources (0.25±0.1 mg/mL vs. 0.91±0.2 mg/mL, p<0.0001). TEE/cardiac CT, performed in 20 (40%) patients, identified a CE source in 5 (25%) cases, whereas DSCT identified 4 (20%), leading to a sensitivity and specificity of 80% (95% CI 28-99%) and 100% (95% CI 78-100%) respectively (kappa 0.86). CONCLUSIONS: In this pilot study, we identified DSCT as a potential unsophisticated approach for the early triage of CE sources among patients with AIS undergoing CTA upon admission.

In Vivo Studies of a Liquid Embolic Compound.

A composition in the form of liquid polymer substance intended for embolization procedures was studied in in vivo experiment. The preparation was injected to rabbits into the femoral artery and abdominal aorta. The polymer composition exhibited properties previously demonstrated in vitro: strong adhesion to the vascular wall, high plasticity sufficient for embolization of the blood vessels, distal distribution, and the absence of toxic effects. The contrast substance remained in the embolus, which simplified its further localization. The agent underwent nether resorption nor organization. Injection of the agent in a volume of 0.1 ml was sufficient for embolization of an artery with a diameter of 0.1 cm. The polymer composition completely obstructed the vessel without inducing perforation of its wall. During the first day of the experiment, a slight infiltration of surrounding tissues with lymphoid cells was observed. By day 7, total dry necrosis of pelvic limb distal to the injection site was diagnosed. Inflammation of the surrounding tissues was shown histologically and was considered as the body response to impaired circulation and necrosis.

Paraplegia After Basketball Play: A Case of Spinal Cord Infarction Secondary to Fibrocartilaginous Embolization.

ABSTRACT: Pediatric emergency medicine providers must be astute at generating the differential diagnosis and performing the appropriate evaluation to promptly determine the underlying cause of new onset paraplegia. Spinal cord infarction (SCI) is a potential etiology of paraplegia in children, and fibrocartilaginous embolization is a rare underlying cause of SCI. We present an illustrative case of SCI secondary to fibrocartilaginous embolization in an otherwise healthy adolescent who developed symptoms of spinal cord dysfunction after basketball play.

The Shaggy Aorta Syndrome: An Updated Review.

BACKGROUND: Shaggy aorta (SA) depicts the severe aortic surface degeneration, extremely friable, and likely to cause spontaneous peripheral and visceral embolization or during catheterization, aortic manipulation, surgery, or minimally invasive procedures. This study aims to provide the most accurate and up-to-date information on this disease. METHODS: Potentially eligible studies to be included were identified by searching the following databases: CENTRAL Library, ClinicalTrials.gov, MEDLINE, and CINAHL, using a combination of subject headings and text words to identify relevant studies: (Shaggy aorta) OR (aortic embolization) OR (aortic embolism) OR (aortic thrombus) OR (aortic plaque). From a total of 29,111 abstracts, and after applying inclusion and exclusion criteria, we considered 60 studies for inclusion in this review. RESULTS: Appropriate measurement and assessment of the aortic wall are pivotal in the modern era, in particular when percutaneous procedures are performed, as SA has been identified as an independent risk factor for spinal cord injury, mesenteric embolization, and cerebral infarction after endovascular aortic repair. Furthermore, SA increases the rate of cerebral complications during transcatheter aortic valve implantation. CONCLUSIONS: In conclusion, prompt diagnosis of SA syndrome and appropriate guidelines on the management of these conditions may help physicians to better assess the patient risk and to minimize the dreadful-related complications.