Swine Model of Myocardial Infarction Induced by Ischemia-Reperfusion and Embolization.

Acute myocardial infarction continues to account for a growing burden of heart failure worldwide. Despite existing therapies, new approaches for reducing the extent of damage and better managing heart failure progression are urgently needed. Preclinical large animal models are a critical step in the translation of scientific discoveries toward clinical trials and therapeutic application. In this chapter, we detail methods to induce swine models of myocardial infarction through catheter-mediated approaches involving either temporary (ischemia-reperfusion) or permanent (thrombus injection or embolic coil) occlusions. These techniques are relatively low in invasiveness, while infarct size with corresponding cardiac dysfunction can be controlled by adjusting the location of coronary occlusion. We also describe methods for cardiac angiography and echocardiography in pigs. This is the second edition of a previously published chapter with modifications.

Cutaneous Hydrophilic Polymer Embolism: An Important and Overlooked Clinical Entity.

ABSTRACT: Hydrophilic polymer embolism from vascular medical devices is an underrecognized clinical entity that can cause deleterious end-organ ischemia and culminate in mortality. This is concerning as we are in the era where minimally invasive procedures are commonplace. Diagnosis is often made retrospectively after obtaining histopathological tissue samples showing endoluminal, cerebriform, amorphous, anucleate, basophilic, nonrefractile, nonpolarizable foreign body material. We detail 2 more cases of cutaneous hydrophilic polymer embolism to underscore its salient clinicopathological features and increase awareness of this important iatrogenic entity.

Posttraumatic Basal Ganglia Infarction by Lenticulostriate Artery Injury in Adult Patients: A Review.

Post-traumatic striatocapsular infarction (SCI) due to lenticulostriate artery (LSA) damage is rare. Most cases reported are in children. We discuss the pathogenesis and differential diagnosis of this kind of SCI after trauma in adult patients. The most common etiology of non-traumatic SCI are an embolism from the proximal artery, cardiogenic embolism, and atherosclerotic plaque in the proximal middle cerebral artery (MCA). However, injury of the LSA after trauma may lead to hemorrhagic infarction in the basal ganglia (BG). Post-traumatic SCI due to LSA damage might be associated with hemorrhage in the BG. The main locations of these lesions are the distal perfusion area of the LSA, similar to SCI due to intracranial atherosclerotic disease affecting the MCA. Vessel wall imaging, magnetic resonance angiography, and ultrahigh-resolution computed tomography can be used for differentiating the injury mechanism in SCI following a traumatic event.

Acceleration of the Development of Microcirculation Embolism in the Brain due to Capillary Narrowing.

BACKGROUND: Cerebral microvascular obstruction is critically involved in recurrent stroke and decreased cerebral blood flow with age. The obstruction must occur in the capillary with a greater resistance to perfusion pressure through the microvascular networks. However, little is known about the relationship between capillary size and embolism formation. This study aimed to determine whether the capillary lumen space contributes to the development of microcirculation embolism. METHODS: To spatiotemporally manipulate capillary diameters in vivo, transgenic mice expressing the light-gated cation channel protein ChR2 (channelrhodopsin-2) in mural cells were used. The spatiotemporal changes in the regional cerebral blood flow in response to the photoactivation of ChR2 mural cells were first characterized using laser speckle flowgraphy. Capillary responses to optimized photostimulation were then examined in vivo using 2-photon microscopy. Finally, microcirculation embolism due to intravenously injected fluorescent microbeads was compared under conditions with or without photoactivation of ChR2 mural cells. RESULTS: Following transcranial photostimulation, the stimulation intensity-dependent decrease in cerebral blood flow centered at the irradiation was observed (14%-49% decreases relative to the baseline). The cerebrovascular response to photostimulation showed significant constriction of the cerebral arteries and capillaries but not of the veins. As a result of vasoconstriction, a temporal stall of red blood cell flow occurred in the capillaries of the venous sides. The 2-photon excitation of a single ChR2 pericyte demonstrated the partial shrinkage of capillaries (7% relative to the baseline) around the stimulated cell. With the intravenous injection of microbeads, the occurrence of microcirculation embolism was significantly enhanced (11% increases compared to the control) with photostimulation. CONCLUSIONS: Capillary narrowing increases the risk of developing microcirculation embolism in the venous sides of the cerebral capillaries.

Morphological characteristics of cardiac myxoma causing embolism: a series of 40 years of experience at a single institute.

Systemic and cerebral embolisms are serious complications of associated with cardiac myxoma. Embolism risk reportedly depends on the gross and histological morphology. This study is aimed at analyzing the morphologic pattern of excised cardiac myxoma as a high-risk embolic cause. Between 1978 and April 2022, 116 surgical specimens of cardiac myxomas were recorded at the pathology department of our hospital. The tumors were classified into three types based on their macroscopic shapes and external morphology-round-smooth, irregular, and villous-to investigate the embolic complications. Of the 116 specimens, 106 macroscopic images of cardiac myxoma (89% were located in the left atrium) were prepared. Round-smooth types were found in 36 (34.0%) patients, irregular types in 32 (30.2%) patients, and the villous types in 38 (35.8%) patients. Multivariable analysis revealed that a villous external appearance was an independent predictor of embolic events (odds ratio: 8.7; 95% confidence interval: 2.4-42.1; p < 0.001). Villous external appearance of cardiac myxoma was associated with the highest risk of distal embolism.

Renal angiomyolipoma with inferior vena cava and right atrial embolism: A case report and literature review. / è‚¾è¡€ç®¡å¹³æ»‘è‚Œè„‚è‚ªç˜¤åˆå¹¶ä¸‹è ”é™è„‰å’Œå³å¿ƒæˆ¿ç˜¤æ “1ä¾‹åŠæ–‡çŒ®å¤ä¹ .

Renal angiomyolipoma (AML) with renal vein, inferior vena cava (IVC), and right atrial embolism is a rare solid tumor, whose etiology and pathogenesis are still unclear. Moreover, it is often misdiagnosed. One patient with renal AML complicated with renal vein, IVC, and right atrial embolism was admitted to the Second Xiangya Hospital of Central South University, who was a 35-year-old female, without any previous medical history, presented with right low back pain for more than 3 years. Computed tomography (CT) scan showed irregular lobulated fatty density mass in the right kidney, renal vein, IVC, and right atrium. The contrast-enhanced scan showed no enhancement of fat components at each phase and mild enhancement of solid components. Radical resection of the right kidney and removal of tumor thrombus were performed, and there was no recurrence 1 year after the operation. It is rare for renal AML to grow along the renal vein, IVC, and extend to the right atrium. Imaging examination is extremely important, and the CT findings of this case are characteristic, but the diagnosis eventually depends on pathological and immunohistochemical examinations.

A Rare Cause of Respiratory Insufficiency in a 30-Year-Old Transgender Woman.

CASE PRESENTATION: A 30-year-old transgender woman who was HIV positive presented to the ED with progressive severe dyspnea and hemoptysis that started 1 day earlier. The patient was undergoing antiretroviral therapy with emtricitabine-rilpivirine-tenofovir with good compliance and feminizing hormone therapy with cyproterone acetate. She was otherwise healthy and was not taking any other medications.

Animal model of coronary microembolization under transthoracic echocardiographic guidance in rats.

The aim of the study was to develop a model of coronary microembolization (CME) in rats at a lower cost. We developed a novel rat model without thoracotomy and ventilation under the guidance of echocardiography. Rats were sacrificed at 3 h, 24 h and 1 month postoperatively in both the Echo-CME and Open-chest CME groups for the comparison of the modeling accuracy, mortality, cardiopulmonary circulation, pleural adhesion and ventilation-induced lung injury (VILI). Results showed that the coronary microthrombus formed at 3 h and reached its peak at 24 h postoperatively, which included platelet aggregation and fibrin web. The Echo-group increases success rates, decreased mortality, postoperative complications including pleural adhesion, cardiopulmonary dysfunction and VILI postoperatively than the Open-chest group at 1month postoperatively. The ejection fraction of the CME group decreased to 50% and obvious cardiac fibrosis formed at 3 months postoperatively. Our unique surgical method provided a platform to study molecular mechanisms and potential new pathways for CME treatment.

Liquid silicone embolism syndrome (SES) in lungs and liver - A case report.

Silicone embolism syndrome (SES) is a well known complication after injection of silicone gel as well as liquid silicone. Rarely, men use physiologic salt solution or liquid silicone injected into the subcutaneous tissue of the scrotum, the penis, the upper genital or the inguinal region. Those men, who call themselves "siliconers", want to get a larger penis and scrotum, also visible when wearing clothes. Injections of liquid silicone in the mentioned regions can lead to liquid silicone embolism in the lungs and also the liver, sometimes eventually leading to death via right heart failure as in the present case. Autopsy revealed "frog spawn"-like vacuoles in the subcutaneous tissue of the genital region and liquid silicone embolism in lungs and liver. Additionally, toxicological analyses revealed different liquid silicones. Smaller oligomers were transported into lung and liver, larger ones showed local enrichment at the injection site. The seized Polydimethylsiloxane (PDMS) could not be detected in abdominal fat, blood or urine, potentially due to low perfusion of fat tissue, the aqueous character of blood and urine or the time span between last injection and death.

A case of fatal embolization during laser lithotripsy.

PURPOSE: To report in literature the first case of fatal multi-organ embolization of ureteral stones fragments during laser lithotripsy. CASE PRESENTATION: A tetraplegic 43-year-old woman was admitted to the hospital to undergo laser lithotripsy because of bilateral ureteral stones and right ureteral infected stent. During the removal of the right ureteral stent, the patient developed a sudden severe bradycardia followed by a reduction in the arterial oxygen saturation. In spite of a rapid and intensive medical intervention, the clinical picture did not improve; the woman was therefore transferred to the nearest Emergency Room where she was rescued but a cardiocirculatory arrest occurred. A claim of alleged medical malpractice was brought against the urologists. A complete autopsy was performed 8 days after death. AUTOPSY FINDINGS: The diagnosis was determined by the microscopic findings: they have unequivocally shown a massive embolization of calculus fragments in the lungs and in the heart. In the light of all these findings, the cause of death was attributable to a disseminated intravascular coagulation due to this unforeseeable embolization of calcified amorphous material. CONCLUSION: Embolization of calculus fragments represents an important challenge because it is extremely unpredictable. Indeed, a prompt diagnosis of non-thrombotic pulmonary embolism, during the urologic procedure, is extremely difficult because the condition presents with no specific clinical signs: this life-threatening pathology is often underestimated. For this reason, the autopsy and the subsequent histopathological examination are indispensable in order to prove lethal embolization: microscopic findings play a key role in the final diagnosis of death.

Cutaneous Polymer-Coating Embolism After Endovascular Procedures: Report of Two Cases and a Literature Review.

ABSTRACT: Different hydrophilic and hydrophobic polymers are used as lubricious coatings to reduce vascular traumas in minimally invasive percutaneous procedures. Although they are usually very safe, there is still a risk of serious complications in patients undergoing such procedures, mostly derived from the devices' coating detachment and systemic embolization. The lungs are the most common organ involved, followed by the central nervous system. Yet, cutaneous embolization is unusual, and only 19 cases are available in the literature. Most commonly, they present as asymptomatic retiform purpura on the lower legs, which tends to involve spontaneously. Correct clinical diagnosis is not suspected in most cases, being cholesterol emboly or vasculitis the preferred options. Time interval since surgical procedure and appearance of lesions vary widely but they generally start in the first few days. Histopathological identification of the embolus as bluish, amorphous intraluminal material in dermal vessels is diagnostic, but vasculitic signs are not present. We report 2 cases of skin lesions as the main manifestation of polymer embolization after endovascular surgical procedures. In both cases, biopsy allowed identification of embolized foreign material and lesions resolved without specific treatment.

Nicorandil inhibits cardiomyocyte apoptosis and improves cardiac function by suppressing the HtrA2/XIAP/PARP signaling after coronary microembolization in rats.

Cardiomyocyte apoptosis is a key factor in the deterioration of cardiac function after coronary microembolization (CME). Nicorandil (NIC) affects myocardial injury, which may be related to the inhibition of apoptosis. However, the specific mechanism of cardioprotection has not been elucidated. Therefore, we analyzed the impact of NIC on cardiac function in rats subjected to CME and its effect on the high-temperature requirement peptidase 2/X-linked inhibitor of apoptosis protein/poly ADP-ribose polymerase (HtrA2/XIAP/PARP) pathway. Sprague Dawley rats were divided into four groups: Sham, CME, CME + NIC, and CME + UCF. Echocardiography was performed 9 hours after CME. Myocardial injury markers were evaluated in blood samples, and the heart tissue was collected for hematoxylin-eosin staining, hematoxylin basic fuchsin picric acid staining staining, TdT-mediated DUTP nick end labeling (TUNEL) staining, Western blot analysis of the HtrA2/XIAP/PARP pathway, and transmission electron microscopy. NIC ameliorated cardiac dysfunctioncaused by CME and reduced serum levels of CK-MB and LDH. In addition, NIC decreased myocardial microinfarct size and apoptotic index. NIC reduced the Bax/Bcl-2 ratio, levels of cleaved caspase 3/9, cytoplasmic HtrA2, and cleaved PARP, and increased the level of XIAP. The effects of NIC were similar to those of the HtrA2 inhibitor, UCF101. This study demonstrated that NIC reduces CME-induced myocardial injury, reduces mitochondrial damage, and improves myocardial function. The reduction in cardiomyocyte apoptosis by NIC may be mediated by the HtrA2/XIAP/PARP signaling pathway.

Generation of Filler Emboli as a Mechanism for Filler-Related Blindness.

BACKGROUND: Intra-arterial injection of fillers can lead to occlusion of the ophthalmic artery or its branches supplying the retina or the optic nerve. The mechanism through which this occurs is incompletely understood. We investigated the possibility of generating microparticles after injecting commercially available fillers into a flowing system in vitro. METHODS: Three hyaluronic acid fillers and one calcium hydroxylapatite filler were injected into an artificial saline flow system mimicking arterial systolic blood pressure and corresponding to the diameter of the facial artery. All the saline at the end of the tube was collected, centrifuged, and inspected for filler particles. RESULTS: After injection into the system, all fillers immediately disintegrated into small particles that were carried downstream with the flow of the saline. The saline at the end of the tube contained collections of filler. CONCLUSION: Hyaluronic acid and hydroxylapatite fillers break up into small particles immediately after injection into a flowing system, generating emboli rather than a column of filler. The results of this study lead us to hypothesize another potential mechanism leading to filler-related blindness.

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.

Lung tumor presenting with acute myocardial infarction and lower extremity arterial embolism.

BACKGROUND: Lung tumor embolization leading to acute myocardial infarction (AMI) is rare. Previouscases of lung tumor embolization were reported in the coronary artery. We describe here a case of lung tumor embolization leading to the simultaneous occurrence of AMI and lower extremity arterial embolism. CASE PRESENTATION: A 64-year-old patient was admitted to the emergency department complaining of chest pain and was diagnosed with AMI.An echocardiography showed a mass in the left atrium that was speculated to be a myxoma. An emergency coronary angiography found no evidence of atherosclerosis. On the second day of admission, the patient was diagnosed with lower extremity arterial embolism. Initially, we speculated that the left atrium myxoma caused an embolism resulting in the AMI and lower extremity arterial embolism.However, a lung tumor was the real cause of both conditions. Unfortunately, the patient abandoned treatment when he learned of his disease and died three days later after being discharged from the hospital. CONCLUSIONS: Lung tumor embolism is an extremely rare cause of AMI. Even rarer is the case presented here, in which a lung tumor embolism caused AMI and lower extremity arterial embolism. Clinicians should recognize lung tumor embolism as a potential cause of AMI.

The risk of stroke/systemic embolism and major bleeding in Asian patients with non-valvular atrial fibrillation treated with non-vitamin K oral anticoagulants compared to warfarin: Results from a real-world data analysis.

BACKGROUND: Although randomized trials provide a high level of evidence regarding the efficacy of non-vitamin K oral anticoagulants (NOACs), the results of such trials may differ from those observed in day-to-day clinical practice. AIMS: To compare the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between NOAC and warfarin in clinical practice. METHODS: Patients with non-valvular atrial fibrillation (NVAF) who started warfarin/NOACs between January 2015 and November 2016 were retrospectively identified from Korea's nationwide health insurance claims database. Using inpatient diagnosis and imaging records, the Cox models with inverse probability of treatment weighting using propensity scores were used to estimate hazard ratios (HRs) for NOACs relative to warfarin. RESULTS: Of the 48,389 patients, 10,548, 11,414, 17,779 and 8,648 were administered apixaban, dabigatran, rivaroxaban and warfarin, respectively. Many patients had suffered prior strokes (36.7%, 37.7%, 31.4%, and 32.2% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), exhibited high CHA2DS2-VASc (4.8, 4.6, 4.6, and 4.1 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) and HAS-BLED (3.7, 3.6, 3.6, and 3.3 in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively) scores, had received antiplatelet therapy (75.4%, 75.7%, 76.8%, and 70.1% in apixaban, dabigatran, rivaroxaban, and warfarin group, respectively), or were administered reduced doses of NOACs (49.8%, 52.9%, and 42.8% in apixaban, dabigatran, and rivaroxaban group, respectively). Apixaban, dabigatran and rivaroxaban showed a significantly lower S/SE risk [HR, 95% confidence intervals (CI): 0.62, 0.54-0.71; 0.60, 0.53-0.69; and 0.71, 0.56-0.88, respectively] than warfarin. Apixaban and dabigatran (HR, 95% CI: 0.58, 0.51-0.66 and 0.75, 0.60-0.95, respectively), but not rivaroxaban (HR, 95% CI: 0.84, 0.69-1.04), showed a significantly lower MB risk than warfarin. CONCLUSIONS: Among Asian patients who were associated with higher bleeding risk, low adherence, and receiving reduced NOAC dose than that provided in randomised controlled trials, all NOACs were associated with a significantly lower S/SE risk and apixaban and dabigatran with a significantly lower MB risk than warfarin.