Chronic Embolism Research Articles

Long-term Results of Stem Cell Therapy for Acute and Chronic Limb Ischemia

Stem cell therapy (SCT) using intramuscular injections of autologous bone marrow mononuclear cells is shown to improve clinical symptoms and prevent major amputation in patients with chronic nonreconstructable peripheral arterial disease (PAD). However, there is limited data regarding the usage of SCT in patients presenting with acute limb ischemia. In an Indian setting, it is not uncommon to see delayed presentation of acute limb ischemia or acute on chronic embolism where revascularization would be suboptimal or not feasible.

Performance of an artificial intelligence tool with real-time clinical workflow integration - Detection of intracranial hemorrhage and pulmonary embolism.

Performance of an artificial intelligence tool with real-time clinical workflow integration - Detection of intracranial hemorrhage and pulmonary embolism.

Treatment of Peripheral Aneurysms - Dual Supera for Popliteal Artery Aneurysms: Immediate and Long-Term Results

Popliteal aneurysms have the highest incidence of all peripheral aneurysms. The clinical symptoms are dominated by chronic embolism, resulting in irreversible ischemia with the associated risk of amputation and mortality, but rupture is less important. Acute aneurysm thrombosis bears a high risk of amputation and mortality. Endovascular exclusion with covered stents instead of open surgery has gained widespread acceptance and is based on reliable data. The principle of flow diversion for aneurysm treatment is well known for the cerebral vasculature, and is now emerging as a potential alternative with promising results and is challenging the concept of complete endovascular aneurysm exclusion or surgical bypassing. Since 2011, thirty-four out of 142 electively treated popliteal aneurysms and 8 thrombosed aneurysms were treated with a bare metal woven Nitinol stent. In this single centre series with continuous mid- to long-term follow-up, as described below, this option showed reliable results in terms of clinical outcome, material fatigue and preservation of outflow vasculature with the option for conversion. The limitation of the technique is determined by the available maximum outer stent diameter of 7.5 mm.

ANGIOIMMUNOBLASTIC T-CELL LYMPHOMA AS A CAUSE OF PERSISTENT PULMONARY HYPERTENSION

SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease 1 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Angioimmunoblastic T-cell lymphoma (AITL) is rare, accounting for 15-20% of peripheral T-cell lymphomas. Diagnosis can be challenging, as AITL may present with symptoms such as rash and arthralgias more suggestive of an autoimmune disorder (1). There are very few published reports of lymphoma-associated pulmonary hypertension (PH), most involving intravascular B-cell lymphomas (2). Here we present a case of AITL-associated PH that did not resolve with lymphoma remission. CASE PRESENTATION: A previously healthy 63-year-old woman presented after weeks of fevers, arthralgias, rashes, and dyspnea on exertion. Pulmonary function testing and CT chest were initially unremarkable. After an equivocal work-up she was provisionally diagnosed with Still’s disease, but saw no improvement on colchicine or anakinra. FDG-PET obtained a year after presentation revealed new pleural and pericardial effusions, splenomegaly, and diffuse lymphadenopathy, but no abnormal uptake in the lungs. Echocardiogram revealed mild RV enlargement with reduced function and an estimated RVSP of 73. A lymph node biopsy was consistent with AITL, a diagnosis further supported by the presence of a TCR gene rearrangement. She was started on chemotherapy with CEOP and had complete response after 2 cycles. Despite her excellent response to chemotherapy, her dyspnea rapidly progressed and repeat PFTs showed interval development of a moderately reduced diffusion capacity. Repeat CT chest was again negative for pulmonary infiltrates and V/Q scan did not suggest chronic embolism. On physical exam she now had JVD, 2+ pitting edema to her knees, and cool extremities. Right heart catheterization confirmed severe PH with mPAP 46 mmHg, normal PAWP, and PVR 13 WU. A thorough evaluation for other causes of PH was unrevealing. The patient’s symptoms improved on PDE5i and ERA therapy; HRCT did not reveal signs of PVOD nor did she develop hypoxia on treatment. DISCUSSION: Lymphoma is a rare cause of PH, and to our knowledge this is only the second reported case of PH due to AITL (3). In that case, as well as in other cases of lymphoma-associated PH, the PH improved or resolved with lymphoma remission. Our patient’s PH continued even after complete response to chemotherapy, and we hypothesize that the delay in diagnosis allowed time for fixed remodeling of the pulmonary arterial endothelium. CONCLUSIONS: Lymphoma may be an underappreciated cause of PH, and should be considered in patients with unexplained PH. AITL, in particular, should be considered in patients with PAH and symptoms suggestive of a systemic rheumatologic disorder. Imaging devoid of interstitial changes does not preclude this diagnosis, particularly once PE, PVOD, and pulmonary capillary hemangiomatosis have been considered. Treatment with PAH therapy was safe and effective in this case. Reference #1: de Leval et al. Br J Haematol. 2010 Mar; 148(5): 673-89 Reference #2: Nelson et al. J Thorac Oncol. 2012 Dec; 7(12): e34-5 Reference #3: Hua J et al. J Hematol Malig. 2012; 2(3): 26. DISCLOSURES: No relevant relationships by Anna Bracewell, source=Web Response No relevant relationships by Sachin Gupta, source=Web Response

Echocardiographic evaluation of prevalence of pulmonary hypertension in β-thalassemia major: A cross sectional study

Introduction: Pulmonary hypertension is a common complication associated with thalassemia syndromes and it may play an important role in the pathogenesis of right ventricle failure. The true prevalence of pulmonary hypertension in patients with thalassemia major remains unclear and has been reported to be between 2 and 79%.Materials and methods: In total, 70 patients with thalassemia major were initially examined. Patients with valvular left heart disease, congenital heart diseases such as atrial septal defect (ASD) and ventricular septal defect (VSD), left heart failure, and chronic embolism were excluded. All patients with thalassemia major underwent echocardiography. Based on tricuspid regurgitation velocity (TRV), the patients were divided into the following three groups: low, medium, and high risk of pulmonary hypertension.Results: The mean age of the subjects was 24 y; 60.6% of the subjects were males and 39.4% of the subjects were females. Overall, three (4.5%) subjects were considered at a high risk of pulmonary hypertension. The mean hemoglobin level in the patients with a high probability of pulmonary hypertension was 8.2 g/dL and that in the patients with a low or medium probability of pulmonary hypertension was 9.1 g/dL. No significant difference was observed between the groups (p = .059).Conclusion: This study showed that, based on new echocardiography criteria, the prevalence of pulmonary hypertension secondary to β-thalassemia was 4.5% and there was no correlation between TRV and the number of received blood units or disease duration.

Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation.

Relatively anisohydric species are predicted to be more predisposed to hydraulic failure than relatively isohydric species, as they operate with narrower hydraulic safety margins. We subjected co-occurring anisohydric Juniperus monosperma and isohydric Pinus edulis trees to warming, reduced precipitation, or both, and measured their gas exchange and hydraulic responses. We found that reductions in stomatal conductance and assimilation by heat and drought were more frequent during relatively moist periods, but these effects were not exacerbated in the combined heat and drought treatment. Counter to expectations, both species exhibited similar gs temporal dynamics in response to drought. Further, whereas P. edulis exhibited chronic embolism, J. monosperma showed very little embolism due to its conservative stomatal regulation and maintenance of xylem water potential above the embolism entry point. This tight stomatal control and low levels of embolism experienced by juniper refuted the notion that very low water potentials during drought are associated with loose stomatal control and with the hypothesis that anisohydric species are more prone to hydraulic failure than isohydric species. Because direct association of stomatal behaviour with embolism resistance can be misleading, we advocate consideration of stomatal behaviour relative to embolism resistance for classifying species drought response strategies.

Medical Therapy for Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary hypertension (PH) secondary to chronic emboli, obstructing the pulmonary arteries. This results in increased pulmonary vascular resistance and right ventricular failure. CTEPH is the only form of PH that is potentially curable, through a surgical procedure that removes the chronic emboli: pulmonary thromboendarterectomy (PTE). The first step in managing patients diagnosed with CTEPH is to determine if they are operable. The use of medical therapy should never delay referral for surgery, which should be done at a specialized center with expertise in CTEPH. Since a significant proportion of CTEPH patients are not surgical candidates, or are among the 10% to 15% of patients that have persistent or recurrent PH after surgery, there is a need for effective medical therapy. The use of several pulmonary arterial hypertension (PAH)-targeted agents have been studied, mostly in small uncontrolled trials. A recent Phase 3 clinical trial found riociguat, a stimulator of soluble guanylate cyclase (sGC), to be effective for inoperable CTEPH.

Chronic Pulmonary Emboli and Radiologic Mimics on CT Pulmonary Angiography: A Diagnostic Challenge

Chronic pulmonary thromboembolism (CPE) is a challenging diagnosis for clinicians. It is an often-forgotten diagnosis and can be difficult to detect and easily misdiagnosed. The radiologic features on CT pulmonary angiography are subtle and can be further compounded by pathologic mimics and unusual findings observed with disease progression. Diagnosis is important because CPE can lead to progressive pulmonary hypertension, morbidity, and mortality. Moreover, chronic thromboembolic pulmonary hypertension is the only category of pulmonary hypertension with an effective curative treatment in the form of pulmonary endarterectomy. Therefore, CPE must be considered and recognized early. The features of chronic pulmonary emboli on CT scans can be categorized into vascular or parenchymal findings. Endoluminal signs include totally or partially occlusive thrombi and webs and bands. Parenchymal features such as mosaic attenuation and pulmonary infarction are also noted, in addition to features of pulmonary artery hypertension. Additional findings have been noted, including cavitation of infarcts, microbial colonization of cavities, and bronchopleural fistulae. As CPE can be diagnosed at different stages of its disease pathway, such findings may not necessarily arouse suspicion toward a causative diagnosis of chronic embolism. To aid diagnosis for clinicians, this article describes the characteristic vascular and parenchymal CT scan features of chronic emboli, as well as important ancillary findings. We also provide an illustrative case series focusing on CT pulmonary angiography specifically as an imaging modality to highlight the progressive nature of CPE and its sequelae, as well as important radiologic mimics to consider in the differential diagnosis.

Nonthrombotic pulmonary embolism

Nonthrombotic pulmonary embolism (NTPE) is defined as embolisation to the pulmonary circulation of different cell types (adipocytes, haematopoietic, amniotic, trophoblastic or tumour), bacteria, fungi, foreign material or gas. The purpose of this article is to describe the clinical signs, pathogenesis, diagnosis and treatment of the different NTPE subtypes. The complex and diverse pathogenesis of different subtypes of emboli is subject to continuing speculation and is certainly far more complex than "simple" mechanical obstruction after embolisation of vascular thrombi. Nonthrombotic emboli may also lead to a severe inflammatory reaction both in the systemic and pulmonary circulation, as well as in the lung. NTPE presents a formidable diagnostic challenge, as the condition often presents with very unusual and peculiar clinical signs that are frequently overlooked. They range from very dramatic acute presentations such as acute respiratory distress syndrome to signs observed late in the disease course. Pathological observations play a key role in the exact diagnosis, and sometimes carefully aspirated blood from the pulmonary artery or specific staining of cells recovered from bronchoalveolar lavage fluid may be helpful. Frequently, lung biopsies revealing severe granulomatous reaction or unfortunate post-mortem pathological investigations of pulmonary tissue are necessary to confirm the diagnosis. Here, we also aim to familiarise the reader with the atypical radiological features of NTPE. Thin-section computed tomography of the lungs showing peculiar radiographic findings, such as a feeding vessel, the so-called tree-in-bud pattern or the appearance of micronodules distributed at the termination of bronchovascular bundles, may be observed in certain forms of NTPE. Increased awareness of NTPE as an underestimated cause of acute and chronic embolism, which may result in acute and chronic pulmonary hypertension, is needed. Despite the fact that detailed descriptions of several forms of NTPE have existed for nearly 100 years, well-designed trials have never been performed to evaluate therapy in the different subsets of these patients.

Right Superior Vena Cava Drainage into the Left Atrium Associated with a Coronary–Cameral Fistula Occluding an Atrial–Septal Defect: First Echocardiographic, Angiographic, and Surgical Description

Right superior vena cava (SVC) drainage into the left atrium causing hypoxemia is a very rare congenital malformation. This anomaly can result in complications of chronic cyanosis and paradoxical embolism. It rarely is associated with any other congenital malformation. This is the first case report of right SVC drainage into the left atrium associated with a coronary cameral fistula. During surgical repair, the aneurysmal part of the cameral fistula was noted to be occluding a defect in the atrial septum. Repair of the cameral fistula and rerouting of the SVC via the atrial septal defect were performed.

PULMONARY ARTERY VASCULAR REACTIVITY AFTER NITRIC OXIDE INHALATION, BEFORE AND AFTER PULMONARY THROMBOENDARTERECTOMY

PURPOSE: After pulmonary embolism, 1 to 3% of these patients develop a chronic embolism, with elevated pulmonary artery pressure and increased pulmonary vascular resistance (PVR). The continuous elevated pressure leads to the remodeling of the small arteries. The responsiveness to the inhaled nitric oxide could be a marker of the presence of non-remodelated vascular bed.

Avaliação da hipertrofia da camada média nos pacientes com embolia pulmonar: estudo anatomopatológico

To compare the arterial response of cases of acute and chronic embolism, seeking to associate ischemic pulmonary remodeling with progression to chronicity. Retrospective analysis of 61 necropsies of patients who died in the Instituto do Coração (31 cases of pulmonary embolism and 30 cases of acute myocardial infarction). Slides of pulmonary tissue were obtained from all cases and analyzed qualitative and quantitatively (medial thickness measurement). Qualitative analysis enabled the differentiation between cases of embolism and the control group, thus characterizing the two groups and defining the adequate choice of the control group. The alterations predominated in patients with embolism (alveolar inflammation and edema, infarction, vasoconstriction, concentric intimal proliferation, presence of thrombus). Quantitative analysis demonstrated higher percent medial thickness in the cases of embolism than in the control group; among the cases of embolism, no differences in intra (acute--19.74 and chronic--20.04) and pre-acinar (acute--18.85 and chronic--18.68) arteries were observed. The lack of difference among the groups with embolism and the higher values of percent medial thickness in the peripheral arteries allow the conclusion that the vascular response is more intense and starts in these arteries.

Chronic pulmonary thromboembolism. Air trapping on computed tomography and correlation with pulmonary function tests.

We evaluated lung attenuation on inspiratory/expiratory computed tomography (CT) and spiral CT angiography (CTA) from patients with chronic pulmonary embolism and correlated the CT findings with pulmonary function test (PFT) results. We retrospectively reviewed 9 patients with chronic embolism (mean age, 62.3 years; 5 women and 4 men). Paired inspiratory, expiratory CT and matching CTA images were reviewed, and lung attenuation was evaluated in each segment. Lower attenuation on inspiratory images and air trapping on expiratory images were subjectively assessed and correlated with PFT results. The relationship between the presence of clot and lung attenuation was evaluated. Nine age-matched normal subjects served as controls. Lower attenuation with mosaic perfusion and air trapping were identified in 6 and 9 patients, respectively (mean scores, 8.1 and 11.3, respectively). Air trapping was identified in 19 (42.2%) of 45 segments with lower attenuation on inspiratory images, but was also noted in 31 segments with normal inspiratory attenuation. Air trapping was associated with the presence of proximal arterial stenosis (P<0.01), and the area showed less contrast enhancement than the adjacent lung (P<0.05). Extent of air trapping correlated inversely with PFT parameters of peripheral airway obstruction such as maximum mid-expiratory flow rate (r=-0.86, P=0.003). On the other hand, extent of mosaic perfusion did not correlate with PFT. Air trapping is commonly seen in chronic embolism and is found in areas of relative hypoperfusion. The extent of air trapping correlates with parameters of peripheral airway obstruction.

Unilateral right pulmonary thromboendarterectomy for chronic embolism: A successful procedure in an infant

Unilateral right pulmonary thromboendarterectomy for chronic embolism: A successful procedure in an infant

Surgical Treatment of Chronic Pulmonary Embolism

Although pulmonary embolism usually presents as an acute clinical problem, it can also present as a chronic disorder. This was suspected by Hart in 191 6 and by Molle in 1920 but it was not until 19 28 that Ljungdahl described two patients with chronic obstruction of the pulmonary arteries. Their symptoms included dyspnea, cyanosis, and palpitations, and they ultimately died with right-sided heart failure. Ljungdahl suggested that obstruction was due to pulmonary emboli, contrary to the concept that in patients with cor pulmonale the process was caused by primary thrombosis of the pulmonary artery. Virchow suspected that pulmonary infarction did not occur in most patients after pulmonary embolism because of adequate bronchial collateral circulation. In 1948, Blalock confirmed these observations by detecting bright red arterial perfusion of pulmonary ves­ sels distal to chronic emboli, but it was not until 19 64 that these collaterals were demonstrated angiographically by Viramonte. An antemortem diag­ nosis of chronic pulmonary embolism (CPE) was made by Carroll, who had the diagnosis confi rmed by thoractomy and demonstration of chronic emboli on biopsy. Although several early surgical attempts were made to remove emboli, the first successful embolectomy for recurrent pulmonary emboli was done by Allison in 1958. The technique for embolectomy for CPE was refined by Cabrol and colleagues (4), who recommended a lateral thoracotomy in order to easily approach the distal pulmonary arterial branches. Daily and associates (8) reported extrapericardial dissection of the pulmonary arteries through a median sternotomy and bilateral thromboend-

Chronic Pulmonary Emboli: Sparing of Affected Regions of Lung from Noncardiogenic Pulmonary Edema

In chronic pulmonary emboli, lung perfusion may be maintained by either recanalization of occluded pulmonary artery segments or collateral bronchial circulation. We present a case of noncardiogenic pulmonary edema superimposed on chronic pulmonary emboli, in which the occluded segments of lung were spared from pulmonary edema, but not from neutrophil infiltration. This case demonstrates that chronic emboli may lead to roentgenographic sparing in noncardiogenic pulmonary edema, similar to that previously reported in acute pulmonary emboli superimposed on noncardiogenic edema.

Chronic systemic Dacron and Teflon embolization of a Beall Model 103 mitral valve prosthesis

A case is presented of chronic systemic Dacron and Teflon embolism arising from a Beall Model 103 mitral valve prosthesis installed 11 years earlier. The emboli induced intense foreign body reaction resulting in numerous microgranulomas throughout the body. Multiple microinfarctions in the brain accounted for repeated episodes of transient ischemic attacks. Wearing of the prosthesis with consequent embolic complications seems to be the inevitable terminal fate of such early models of the Beall valve. Regular assessment of the functional status of such prostheses, particularly those in place for more than 5 years, is strongly recommended.

Leiomyosarcoma of The Pulmonary Artery

To the Editor:— Sarcomas originating in the pulmonary vasculature are rare, and 16 have been reported to date. None of these tumors was correctly diagnosed ante mortem or prior to thoracotomy. We wish to present an additional case because its almost perfect mimicry of a chronic embolus led to surgery. Report of a Case:— A 53-year-old white woman was first seen at an outside hospital in December 1963 with a one-year history of gradually increasing exertional dyspnea. Although a nonsmoker, she had had a productive cough for 15 years. Three days prior to being seen, markedly increased dyspnea, fever, and right sided pleuritic pain developed. A chest x-ray film revealed an infiltrate in the lower lobe of the right lung. With antibiotic therapy, she gradually improved, though x-ray film changes were slow to resolve. During the next seven months, the dyspnea progressed, and subsequent chest x-ray films revealed a small

Angiography in pulmonary embolism.

Pulmonary angiography has been performed in the study of 50 patients with suspected pulmonary emboli. The roentgenographic findings in acute and chronic embolism, both massive occlusions within the main pulmonary arteries and lesser peripheral obstructions, have been observed. Not only may the diagnosis of pulmonary embolism be made, but the extent and location of emboli are apparent. Angiographic signs of partial vessel patency are noted and the complete process of organization of the embolus is described. These factors are most important when surgical intervention is anticipated.