Pulmonary Microembolism Research Articles

Activity of protein C, protein S and antithrombin 3 in COVID-19 patients treated with different modalities of oxygen supplementation

Abstract Objectives COVID-19 in it is more severe form is characterized by a hyperinflammatory condition, hypercoagulation state and the appearance of pulmonary microembolism. In this study we wanted to correlate levels of D-Dimer, protein C, protein S and antithrombin 3 with severity of disease and clinical outcome. Methods We included 134 of patients who were divided in 3 groups regarding oxygen support (high flow oxygen therapy, mechanical ventilation and oxygen supplementation with nasal cannula or mask). Results Concentration of D-Dimer, and activity of protein C and antithrombin 3 are presented as mean±SD and differed significantly between patients on mechanical ventilation (3.26 ± 1.15 mg/L, 86 ± 22.55 %, 81.21 ± 17.61 %)/HFNO (2.35 ± 1.68 mg/L, 109.6 ± 26.96 %, 94.67 ± 17.49 %)/BNC (1.37 ± 1.17 mg/L, 116.92 ± 28.16 %, 103.29 ± 15.63 %) with p<0.001 for all parameters. Mortality in oxygen group was 10.9 %, in HFNC group 40.7 % and in mechanical ventilated group 80 %. Conclusions determination of anticoagulant factors in COVID-19 patients may indicate which of them are at increased risk of developing severe disease, venous thromboembolism and fatal clinical outcome.

Anaesthetic challenges in a patient with eisenmenger syndrome: A case report

The term Eisenmenger syndrome describe a large left-to-right cardiac shunt. Occur in 8% of patients with congenital heart disease. Pregnancies carries very high risk of mortality and premature delivery. 20-30% pregnancies result in spontaneous abortion and premature delivery. Pulmonary microembolism and macroembolism have caused peripartum maternal death even after delivery. Anaesthetic management is challenging due to the patho-physiology of the shunt. Our case report is a 27-year-old female known case of Eisenmenger syndrome with chronic thromboembolism presented with inevitable abortion scheduled to undergo emergency evacuation under general anaesthesia.

Thalassemia and COVID-19: Susceptibility and Severity

Context: COVID-19 results in an imbalance between procoagulant and anticoagulant homeostatic mechanisms that could be complicated with thrombotic events. In β-thalassemia patients, the presence of comorbidities, iron overload, adrenal hypofunction, splenectomy, and chronic hypercoagulable state might increase the susceptibility to COVID-19 and its severity. Evidence Acquisition: The search was conducted in PubMed, Web of Science, and Scopus databases for the key terms of β-thalassemia/thalassemia and COVID-19 until July 2021. Results: The survey of published observational studies (mostly multicenter and case reports) indicated a lower prevalence of COVID-19 in β-thalassemia patients compared with the general population, as well as mild to moderate COVID-19 in these patients, especially in those without comorbidity. β-Thalassemia children were susceptible to COVID-19 but with less severity compared to adults. There is no report of pulmonary embolism and thrombotic events in β-thalassemia patients with COVID-19; however, coagulation abnormality and pulmonary microembolism have been found in these patients. Conclusions: Findings could be interpreted by the presence of high hemoglobin F (HbF) levels, the advantage of hydroxyurea (HU) therapy, splenectomy, and iron chelation therapy in these patients. However, due to the low sample size and studying mainly young patients, the results should be interpreted with caution, and it still needs more studies with a larger sample size to confirm these findings.

P1816 Cerebral microembolism in low-risk patients with paroxysmal atrial fibrillation before and after pulmonary vein isolationCerebral microembolism in low-risk patients with paroxysmal atrial fibrillation

Abstract BACKGROUND Invasive treatment of atrial fibrillation (AF) becomes more suitable and effective therapy. There are no consistent data describing the occurrence of potential neurological complications in low-risk patients with paroxysmal AF. AIM to determine the occurrence, consequences and risk factors for brain white matter hiperintensities (WMH) assessed in magnetic resonance imaging (MRI) in low-risk patients before and after pulmonary vein isolation (PVI) treatment. METHODS Eighty patients with symptomatic paroxysmal AF (median age: 58 years (IQR 50-63), K/M: 30/50), CHA2DS2-Vasc ≤ 3 (CHA2DS2-Vasc: 2 (IQR 1-2.5)) were included in the study. Before and after a minimum of 6-month period after PVI-RF treatment (med. 9,9 months, IQR 7.6-11.8 months) a clinical evaluation with brain MRI and Mini Mental State Examination (MMSE) test were determined. Severity of brain WMH in MRI was assessed in the Fazekas scale (pic 1). The efficacy of PVI-RF treatment analyzed in a 7-day Holter monitoring was confirmed in 43 (53.8%) patients. RESULTS Baseline WMH lesions were found in 55 (68.8%) patients. Patients with baseline WMH lesion obtained similar results in the MMSE test, compared to patients with a normal brain image in the MRI study. There was a statistically significant more frequent occurrence of cerebral WMH lesions among older patients, with a higher CHA2DS2-Vasc score, with left atrial (LA) dilatation and dysfunction. Factors affecting the severity of the WMH were: the co-occurrence of the patent foramen ovale (PFO) and coronary artery disease (CAD). After PVI-RF treatment there were no significant changes in the presence and severity of WMH lesions. Similarly, there were no significant changes in the cognitive abilities assessed with MMSE test compared to the pre-procedural evaluation. There were also similar factors predisposing to brain WMH changes: older age, higher CHA2DS2-Vasc score and higher BMI. In turn, the degree of the brain WMH severity after observation period was dependent on age, higher CHA2DS2-Vasc score, presence of PFO and CAD and the initial LA function. CONCLUSIONS Cerebral microembolism assessed in MRI is often found in low-risk patients with paroxysmal AF, and its presence and severity are associated with LA dilatation and dysfunction, age and higher CHA2DS2-Vasc score. Additional factors affecting the severity of WMH lesions are: the co-occurrence of PFO and CAD. PVI-RF procedure and its efficacy does not influence on MRI lesions. In the population of relatively young AF patients with no significant cardiovascular disease burden, cerebral microembolism is not related to cognitive impairment. Abstract P1816 Figure. pic 1

Fatal cardiac perforation and pulmonary embolism of leaked cement after percutaneous vertebroplasty

Percutaneous vertebroplasty consists of percutaneous injection of polymethylmethacrylate (PMMA) via a transpedicular approach for the treatment of collapsed osteoporotic or metastatic vertebrae. Even if percutaneous vertebroplasty is considered to be minimally invasive, threatening complications can occur. Cement leakage is the most common complication of percutaneous vertebroplasty. Rigorous patient selection and individual therapeutic strategy may reduce the occurrence of leakage, in particular the risk of cement entry into the venous system and the spinal canal is the potent major hazard of this technique. Cement pulmonary and cardiac embolism are reported in literature as a cause of unexpected death after percutaneous vertebroplasty. Authors report a fatal case of pulmonary cement embolization occurred after vertebroplasty with haemopericardium, due to the perforation of the right atrium wall from a cement solidified fragment. A complete post mortem examination documented the presence of multiple cement fragments in the pulmonary arteries and transmural perforation of the wall of the right atrium by a whitish needle-like foreign body. Pulmonary microembolization was observed under polarized light.

68Ga-DOTANOC Focal Pulmonary Activity With No Corresponding CT Abnormality

A 28-year-old woman with medullary thyroid cancer treated with total thyroidectomy and bilateral central and right lateral neck nodal resection postoperatively had increasing calcitonin and carcinoembryonic antigen values. A Ga-DOTANOC PET/CT study performed showed tracer-avid disease in the neck, mediastinal, and hilar lymph nodes. However, there were 3 tracer-avid foci in the lungs bilaterally, suggestive of lung metastases but with no corresponding abnormalities on low-dose CT. A negative contrast-enhanced CT of the lungs along with clinical and radiological follow-up confirmed that the lung activity was artifactual, demonstrating the possibility of Ga-DOTANOC-avid iatrogenic pulmonary microembolism.

Aberrant coagulation causes a hyper-inflammatory response in severe influenza pneumonia.

Influenza A virus (IAV) infects the respiratory tract in humans and causes significant morbidity and mortality worldwide each year. Aggressive inflammation, known as a cytokine storm, is thought to cause most of the damage in the lungs during IAV infection. Dysfunctional coagulation is a common complication in pathogenic influenza, manifested by lung endothelial activation, vascular leak, disseminated intravascular coagulation and pulmonary microembolism. Importantly, emerging evidence shows that an uncontrolled coagulation system, including both the cellular (endothelial cells and platelets) and protein (coagulation factors, anticoagulants and fibrinolysis proteases) components, contributes to the pathogenesis of influenza by augmenting viral replication and immune pathogenesis. In this review, we focus on the underlying mechanisms of the dysfunctional coagulatory response in the pathogenesis of IAV.

ROS scavenger decreases basal perfusion pressure, vasoconstriction and NO synthase activity in pulmonary circulation during pulmonary microembolism.

Two mechanisms contribute in the development of pulmonary hypertension in pulmonary embolism (PE) - obstruction of pulmonary blood vessels and vasoconstriction. We hypothesize that hypoxia, increased shear stress and/or activation of gathered leukocytes in the PE may cause a release of reactive oxygen species (ROS). Therefore our aim was to determine the influence of the ROS scavenger Tempol on pulmonary hypertension and to describe NO synthase activity and production of NO oxidative products (NOx) after PE. In general anesthesia sephadex microspheres suspended in PSS were applied in right jugular vein as the pulmonary microembolism. Than we measured in isolated salt solution-perfused lungs the changes in perfusion pressure, activity of NO synthase and NOx plasma concentration in 7 groups of rats: C: control group (n=5), CN: C + sodium nitroprusside (SN) (n=5), EN: PE + SN (n=5), ETN: Tempol + PE + SN (n=5), CL: C + L-NAME (n=5), EL: PE + L-NAME (n=5), ETL: Tempol + PE + L-NAME (n=5). Tempol was applied intraperitoneally before PE. Animals that received Tempol (groups TN, TL) had significantly lower basal perfusion pressure than those which did not receive Tempol (EN, EL). Overall we measured a higher decrease of perfusion pressure than in the control group (C) after application of SN. Administration of L-NAME after PE (EL) increased the pressure more than in the control group (NL). NOx concentration was higher after PE. We found that preventive administration of Tempol decreases the increase in perfusion pressure after PE. PE increased NO release and concentration of NOx.

Bilateral multiple pulmonary 18F-FDG microembolisms demonstrated on PET/CT

Bilateral multiple pulmonary 18F-FDG microembolisms demonstrated on PET/CT

Trisacryl Gelatin Microembolism and Metastases in the Lung after Renal Artery Embolization and Nephrectomy for Renal Cell Carcinoma.

This is the first report, to our knowledge, of widespread, histologically confirmed trisacryl gelatin pulmonary microembolism after renal artery embolization (RAE). In addition, this is the first report of lung involvement by both metastatic renal cell carcinoma (RCC) and an embolic agent used for RAE. The patient was a 63-year-old woman who recently presented with both dyspnea on exertion and productive cough. Her past medical history included clear cell RCC, which was treated with preoperative trisacryl gelatin microsphere RAE and right nephrectomy 9 years earlier. Computed tomography of the chest showed multiple lung nodules, a mass-like density in the left lower lobe, and mediastinal and hilar lymphadenopathy. Wedge resections of the lung showed multiple foci of metastatic RCC and extensive involvement of the muscular pulmonary arteries by trisacryl gelatin microspheres.

Proximal pulmonary arterial obstruction decreases the time constant of the pulmonary circulation and increases right ventricular afterload

The time constant of the pulmonary circulation, or product of pulmonary vascular resistance (PVR) and compliance (Ca), called the RC-time, has been reported to remain constant over a wide range of pressures, etiologies of pulmonary hypertension, and treatments. We wondered if increased wave reflection on proximal pulmonary vascular obstruction, like in operable chronic thromboembolic pulmonary hypertension, might also decrease the RC-time and thereby increase pulse pressure and right ventricular afterload. Pulmonary hypertension of variable severity was induced either by proximal obstruction (pulmonary arterial ensnarement) or distal obstruction (microembolism) eight anesthetized dogs. Pulmonary arterial pressures (Ppa) were measured with high-fidelity micromanometer-tipped catheters, and pulmonary flow with transonic technology. Pulmonary ensnarement increased mean Ppa, PVR, and characteristic impedance, decreased Ca and the RC-time (from 0.46 ± 0.07 to 0.30 ± 0.03 s), and increased the oscillatory component of hydraulic load (Wosc/Wtot) from 25 ± 2 to 29 ± 2%. Pulmonary microembolism increased mean Ppa and PVR, with no significant change in Ca and characteristic impedance, increased RC-time from 0.53 ± 0.09 to 0.74 ± 0.05 s, and decreased Wosc/Wtot from 26 ± 2 to 13 ± 2%. Pulse pressure increased more after pulmonary ensnarement than after microembolism. Concomitant measurements with fluid-filled catheters showed the same functional differences between the two types of pulmonary hypertension, with, however, an underestimation of Wosc. We conclude that pulmonary hypertension caused by proximal vs. distal obstruction is associated with a decreased RC-time and increased pulsatile component of right ventricular hydraulic load.

Focal FDG Uptake in Lung Parenchyma Without Structural Alterations on CT

Transient visualization of a FDG avid abnormality in the lungs without any structural lesion is reported in a case of iatrogenic pulmonary microembolism

Clot penetration and retention by plasminogen activators promote fibrinolysis

Tissue-type plasminogen activator (tPA) remains the sole thrombolytic approved by the FDA for the treatment of pulmonary embolism (PE). tPA has not been replaced by third generation plasminogen activators, e.g. Reteplase (Ret) and Tenecteplase (TNK) that circulate with longer life-spans and in theory should have more extended potency in vivo. One reason for this paradox is the inability to assign units of activity to plasminogen activators based on specific biologically relevant standards, which impairs objective comparison. Here, we compare clot permeation, retention and fibrinolytic activities of tPA, TNK and Ret in vitro and clot composition over time with outcome in a mouse model of disseminated pulmonary microembolism (ME). When clots were incubated in the continuous presence of drug, tPA, TNK and Ret lysed fibrin clots identically in the absence of PA inhibitor-1 (e.g. PAI-1). Ret, which has lower fibrin affinity and greater susceptibility to inhibition by PAI-1 than tPA, was less effective in lysing plasma clots, while TNK was less effective when the fibrin content of the clots was enhanced. However, when clots were afforded only brief exposure to drug, as occurs in vivo, Ret showed more extensive clot permeation, greater retention and lysis than tPA or TNK. These results were reproduced in vivo in a mouse model of ME. These studies indicate the need for more relevant tests of plasminogen activator activity in vitro and in vivo and they show that clot permeation and retention are important potential predictors of clinical utility.

Pulmonary FDG uptake without a CT counterpart – a pitfall in interpreting PET/CT images

Abnormal pulmonary 18F-FDG foci may occur with benign lesions like pneumonia but seldomly without any pathological CT findings. We report the case of a focal pulmonary 18F-FDG uptake without CT correlate in an initial staging examination of a patient with squamous cell carcinoma of the base of the tongue. A follow-up study did not show any suspicious lesion in this area, but pneumonia with 18F-FDG uptake in another region of the lung. 18F-FDG foci without pathological CT are a rare finding and have been associated with emboli. In the literature two main mechanisms underlying focal 18F-FDG uptake in pulmonary embolism are mentioned: an inflammatory reaction of a pre-existing vascular thrombus and an iatrogenic microembolism caused during injection. In our case the 18F-FDG accumulation was assessed as an iatrogenic pulmonary microembolism.

Pulmonary micro-embolism in a healthy donor following G-CSF administration for mobilization of hemopoietic progenitor cells

Pulmonary micro-embolism in a healthy donor following G-CSF administration for mobilization of hemopoietic progenitor cells

Deep vein thromboembolism after arthroscopy of the shoulder: two case reports and a review of the literature

BackgroundDeep vein thrombosis (DVT) has an incidence of 1 case per 1000 inhabitants in the general population and it is very rare after arthroscopy of the shoulder. Therefore, the current guidelines do not advise the administration of DVT prophylaxis in shoulder arthroscopy procedures.Cases presentationWe describe two cases of thrombosis of the arm after shoulder arthroscopy on a total of 10.452 shoulder arthroscopies performed during a period of ten years. One of two patients was further complicated by a bilateral pulmonary microembolism. In these two clinical cases the complication developed despite the absence of risk factors such as a concomitant neoplasm, thrombophilia, smoking habit, or a long duration of the procedure.ConclusionsThe DVT after shoulder arthroscopy procedure remain a very rare complication. However, in view of the growing number of patients undergoing this procedure, this figure is expected to rise. The clinician surgeon should take in mind this possible complication that normally appears in the first 3 weeks after surgery, so to perform anti-coagulant treatment. Further clinical studies are therefore warranted to assess the true risk of VTE. In fact, the presence of "minor" predisposing factors that are not routinely studied, as well as the postoperative immobilization period, are potential risk factors that, associated with the invasiveness of the arthroscopy procedure, could trigger a thromboembolism.

Role of nitric oxide in vasoreactivity caused by experimental pulmonary microembolism

Pulmonary hypertension caused by acute pulmonary embolism has been attributed to mechanical obstruction of the pulmonary arteries and also to vasoconstriction. We examined the role of nitric oxide in the vasoreactivity associated with pulmonary microembolism. Two kinds of microemboli of similar size were used: thorny microemboli (lycopodium spores, LP) and smooth microemboli (latex microspheres, MS). In isolated rat lungs perfused with blood, five injections of LP or MS into the pulmonary artery each caused a rapid increase in mean perfusion pressure, followed by a slow fall to a new, higher base line. Vasoconstriction was significantly greater after embolization with LP than after embolization with MS. Preadministration of L-NMMA, a nitric oxide synthase inhibitor, enhanced the increase in mean perfusion pressure caused by embolization with LP, but not the increase caused by embolization with MS. Before embolization, acetylcholine caused slight vasodilation. After embolization with MS, acetylcholine caused vasodilation; but after embolization with LP, acethlcholine caused vasoconstriction. Thus, we conclude that repeated embolization with LP may cause endothelial injury, and that nitric oxide may protect against pulmonary hypertension induced by LP emboli.

Post-traumatic pulmonary microembolism--bone marrow and fat embolism of the rabbit lung in fracture with special reference to the initial lesions

Post-traumatic pulmonary microembolism--bone marrow and fat embolism of the rabbit lung in fracture with special reference to the initial lesions

Effects of vasoactive substances on changes of pulmonary circulation in barium sulfate-induced pulmonary microembolism in the dog (author's transl)

Effects of vasoactive substances on changes of pulmonary circulation in barium sulfate-induced pulmonary microembolism in the dog (author's transl)

Trauma and Substance Abuse: Deadly Consequences of Intravenous Percocet Tablets

Background: The prevalence of drug or alcohol addiction among trauma patients approaches 40%, yet many require narcotics during admission for adequate pain control. Provider awareness is the most reasonable option to avoid the devastating consequence of narcotic tablet injection. Objective: To illustrate the misuse of oral narcotics and to heighten provider awareness of a potential cause for acute respiratory failure in recently discharged patients. Case Report: A 20-year-old man was admitted to the hospital after an assault to the head and face. He was discharged from the hospital with 30 oral Percocet® (Endo Pharmaceuticals, Newark, DE) tablets after 24 h of observation. The day after discharge, emergency medical services were called to his residence for a decreased level of consciousness. During transport to the Emergency Department, he went into cardiac arrest with pulseless electrical activity. He could not be resuscitated. Postmortem biochemical and anatomical evidence suggested that the patient had attempted to inject crushed Percocet® tablets, which resulted in acute foreign body pulmonary microembolism and death. Conclusion: Patients with a history of substance abuse may be inclined to crush and inject oral narcotics. Narcotic injection should be considered in recently discharged patients who present with pulmonary failure. Patients with suspected narcotic addiction should be counseled before discharge on the risks of misusing oral medications in this fashion.