Quantitation of pulmonary emboli with pulmonary cineangiography: preliminary report

Pulmonary angiography is considered the definite method of diagnosing pulmonary emboli. It is hypothesized that pulmonary cineangiography is superior to conventional pulmonary angiography for quantitation of pulmonary emboli. The present study was undertaken to test the hypothesis. Six patients with an age range from 27 to 70 years with documented pulmonary emboli by pulmonary angiogram, had pulmonary cineangiograms. Pulmonary angiogram defined pulmonary emboli in nine major vessels in the six patients; while, pulmonary cineangiogram revealed another 10 major vessels with pulmonary emboli, which were either not detected or considered equivocal by the conventional pulmonary angiography. The pulmonary embolic score as an index of the extent of pulmonary emboli was 24 (mean 4 +/- 2.52 1SD) by the conventional pulmonary angiography, while the score was 60 (mean 10 +/- 3.22 1SD) by the pulmonary cineangiography, P less than 0.2. Thus, in cases with pulmonary emboli, pulmonary cineangiogram is superior to conventional pulmonary angiogram for the quantitation of pulmonary emboli.     

Detection of intracardiac thrombi in a case of cardiomyopathy by two dimensional echocardiography.

A case of cardiomyopathy with systemic emboli is reported. Two dimensional and M-mode echocardiography showed abnormal intracavitary echoes. After further systemic emboli, echocardiograms showed the complete disappearance of the abnormal echoes found previously in the apex, which suggested that the emboli resulted from detachment of the left ventricular mural thrombi.     

Cardiac metastasis of melanoma presenting as acute aortic occlusion

Cardiac diseases are the most common cause of acute arterial emboli, however, cardiac tumors are not as frequent. Cardiac metastases from melanoma are usually silent, and rarely cause symptoms. Only a few reports are found in the literature of metastatic melanoma, causing arterial emboli. Here, we report a case of a cardiac metastasis of melanoma cancer that presented preoperative as arterial emboli. The gross appearance of the emboli already suggested the presence of a cardiac tumor. In selected patients who have a solitary intracardiac melanoma, surgical resection can provide relief from clinical symptoms and minimize potential cardiac sequelae of the tumor.     

The clinical features of submassive and massive pulmonary emboli

Clinical findings in 167 patients with angiographically established pulmonary emboli were analyzed in detail. The clinical symptoms and physical findings in this group were compared with the findings in 160 patients (diagnosis established by angiography) from an earlier similar study. The observations from this, the largest known group of patients with documented pulmonary emboli that has been studied and reported on, revealed that many of the “classic signs and symptoms” occurred infrequently. Most patients in this study had recognizable predisposing conditions, and some of these are of prognostic value. The data from this study demonstrate that no clinical findings are specific for the diagnosis of pulmonary emboli, but the absence of isolated frequently occurring signs and symptoms should mitigate against the presence of pulmonary emboli.     

The safety of intraosseous infusions: risks of fat and bone marrow emboli to the lungs

The technique of intraosseous infusion is a life-saving emergency alternative when IV access is impossible or will be critically delayed. Concerns about its safety remain, especially concerning the risk of bone marrow and fat emboli to the lungs. We examined autopsy pulmonary specimens on two children who had received intraosseous infusions during resuscitation attempts and found an average of 0.23 to 0.71 bone marrow and fat emboli per mm2 of lung. We studied normotensive dogs with intraosseous infusions of emergency drugs and solutions into the distal femur. Three dogs were studied with each of the following emergency drugs or solutions: controls with normal saline (0.9% NaCl), epinephrine 0.01 mg/kg, NaHCO3 1 mEq/kg, CaCl 10 mg/kg, atropine 0.01 mg/kg, hydroxyethyl starch 6% in normal saline 10 mL/kg, 50% dextrose in water 0.25 g/kg, and lidocaine 1 mg/kg. Four hours after infusion, the animals were killed, and representative sections of the lung were examined with oil red-0 and hematoxylin and eosin stains for the presence of fat and bone marrow emboli. Fat and bone marrow emboli were found in all lung sections, varying from 0.11 to 4.48 emboli/mm2 lung (mean, 0.91 emboli/mm2 lung) for the emergency drugs and solutions and 0.06 to 0.53 emboli/mm2 (mean, 0.29 emboli/mm2 lung) for the controls. Analysis of variance revealed no significant difference (P = .07) in mean number of fat and bone marrow emboli per square millimeter of lung among the emergency drugs and compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Effect of Arvin on Experimental Pulmonary Embolism in the Rabbit

S ummary . Arvin therapy produced alterations in the histological structure of experimental pulmonary emboli in rabbits. Early and extensive necrosis was observed in the emboli which were not organized by fibroblasts. The emboli disappeared more rapidly from the pulmonary vessels than in non-treated animals.     

Multiple instances of peripheral artery emboli from occult primary small cell lung cancer

Most peripheral artery emboli originate in the heart, and systemic neoplastic emboli are infrequently associated with bronchogenic carcinoma. To our knowledge, there have been no reports of pulmonary vein infiltration by small cell lung cancer.We describe a highly unusual case of multiple instances of peripheral embolism as the first overt sign of occult primary small cell lung cancer. Tumor emboli infiltrated the pulmonary veins of a 62-year-old man who presented first with a transient ischemic attack and then with other ischemic symptoms. The uncommonly wide distribution of tumor emboli over a short time resulted in death.Improvements in diagnostic imaging have led to the early identification of relatively isolated small cell lung cancers. This patient's case underscores the importance of transesophageal echocardiography in detecting cardiac emboli when the cause of cerebral ischemic attack is unknown or if there might be multiple instances of arterial embolism. Computed tomography also has a role in the investigation of possible sources of emboli and unrecognized, asymptomatic embolization.     

Pulmonary Tumor Thrombotic Microangiopathy from Metastatic Gallbladder Carcinoma: An Unusual Cause of Severe Pulmonary Hypertension

Pulmonary hypertension and cor pulmonale due to tumor emboli causing pulmonary tumor thrombotic microangiopathy (PTTM) is rare and extremely difficult diagnosis to make prior to death. Pulmonary hypertension due to metastatic tumor emboli should be included in the differential diagnosis of various causes of dyspnea in patients with a history of cancer or more common causes, including infection, thromboembolism, metastasis, adverse effects of drugs, and recurrent effusions. We describe a patient with gallbladder carcinoma who presented with progressive dyspnea and severe pulmonary hypertension. The etiology was tumor emboli and PTTM from gallbladder carcinoma, which remained elusive prior to her death despite appropriate clinical investigations and was established on autopsy. To the best of our knowledge, this is likely the second reported case of PTTM from metastatic gallbladder carcinoma.     

Measurement of growth rate of laser-induced intravascular platelet aggregation and the influence of blood flow velocity.

The growth rate of platelet microthrombi induced by laser injury in ear chamber arterioles on conscious rabbits was measured. A growth rate constant was obtained for each microthrombus by plotting its volume change on a semilogarithmic plot. In most instances each platelet microthrombus formed at any one injury site conformed to a similar growth rate pattern. There was a direct positive correlation between the mean growth rate constant and the number of emboli counted for each laser injury. Blood flow velocity had a variable effect on the number of emboli from sites of laser injury. At velocities above 2.5 mm sec^?1 the number of emboli remained relatively constant; between 1.0 and 2.5 cm sec^?1 the number of emboli tended to increase and there was a greater variation at this level; below 1.0 mm sec^?1 the number of emboli decreased. The number of platelets participating in formation of a microthrombus was expressed as a percentage of the number of available platelets to give a measure of platelet aggregability in vivo. Platelet aggregability varied with alterations in blood flow velocity. At blood flow velocities between 1.0 and 2.5 mm sec^?1 the percentage of platelets participating varied between 20 and 50%, but at velocities above 3.0 mm sec^?1 the percentage decreased to less than 20%. The results suggested that the number of emboli was an indirect measurement of the growth rate of microthrombi forming at sites of laser injury. Further, both the number of emboli and the percentage platelet aggregability in vivo were not significantly affected by changes in blood flow velocity over the range normally found in rabbit ear chamber arterioles.     

Pleural effusion due to pulmonary emboli

Pulmonary embolism is the fourth leading cause of pleural effusion. The possibility of pulmonary embolus should be evaluated for all patients who have undiagnosed pleural effusion. The mechanism of pleural effusion caused by pulmonary embolus is usually increased interstitial fluid in the lungs as a result of ischemia or the release of vasoactive cytokines. Approximately 75% of patients with pulmonary emboli and pleural effusion have pleuritic chest pain. The most common cause of pleuritic chest pain and pleural effusion in patients under 40 years old is pulmonary emboli. Pleural effusion resulting from a pulmonary embolus usually occupies less than one-third of the hemithorax. Dyspnea is frequently out of proportion to the size of the pleural effusion. Pleural fluid caused by pulmonary emboli is usually exudative but is occasionally transudative. d-Dimer testing is a good screen for pulmonary emboli. If d-dimer results are positive, then a spiral computed tomograph should be obtained to confirm the diagnosis. Low-molecular-weight-heparin has become the initial treatment of choice for patients with pulmonary emboli and pleural effusion.     

Tree-in-bud sign as a manifestation of localized pulmonary lymphatic metastasis from a pancreas cancer

The tree-in-bud appearance usually reflects benign disorders of the bronchovascular bundle. Pulmonary metastasis reportedly also shows a tree-in-bud pattern in cases of dilated peripheral pulmonary artery filled with intravascular tumor emboli or fibrocellular intimal hyperplasia of the small pulmonary arteries induced by tumor microemboli, or endobronchial metastatic disease. On X-ray CT, pulmonary metastases may result in four main types of imaging manifestations: nodules, lymphatic spread, tumor emboli, and endobronchial tumor, and show diffuse interstitial thickening or multiple nodules in general. We report a rare case of localized pulmonary peribronchovascular lymphatic tumor spread without intravascular tumor emboli from a pancreas cancer, which mimicked the localized vascular tree-in-bud sign.     

Pulmonary embolism in respiratory failure

The occurrence of pulmonary emboli in 617 patients admitted to a respiratory intensive care unit was studied. Pulmonary emboli were found in 18 (27 percent) of 66 autopsies. Half of these pulmonary emboli were not diagnosed before death, despite persistent aggressive attempts to document pulmonary emboli. In this subpopulation of patients with respiratory failure, the usual clinical manifestations of pulmonary emboli (symptoms, signs, chest x-ray film, electrocardiogram, and changes in arterial blood gas levels) frequently are already present, due to the severe underlying pulmonary disease, and any superimposed manifestations of pulmonary emboli are often inapparent. In this group under study, the ventilation/perfusion lung scan correlated poorly with pulmonary angiographic results and with examinations at autopsy; the scan generally was inadequate to rule in or rule out pulmonary emboli. Again, this was due to the distortion of both ventilation and perfusion by the severe underlying pulmonary disease. Currently, pulmonary angiographic studies remain the only reliable technique to confirm or exclude pulmonary emboli in patients with respiratory failure.     

16层螺旋CT肺动脉造影对肺栓塞诊断价值

目的探讨16层螺旋CT肺动脉造影对肺栓塞的诊断价值。方法分析55例肺栓塞病例,观察16层螺旋CT对肺动脉显影以及肺栓塞的显示情况。结果 55例患者肺部动脉及分支管腔中共发现栓子380个,栓塞率达24.4%,其中肺动脉干栓子4个,栓塞率7.3%;叶肺动脉栓子105个,栓塞率32.3%。其中中心型栓子69个,比例为18.2%;完全堵塞型栓子54个,比例为14.2%;偏心型栓子最多,为195个,比例为51.3%;附壁型栓子62个,比例为16.3%。结论 16层螺旋CT肺动脉造影能高分辨率地显示肺部动脉管腔对肺部腔内栓子进行精确定位和有效评价。     

Paradoxical cerebral embolism causing internal carotid artery occlusion

Paradoxical cerebral embolism (PCE) is defined to be a pathological condition in which emboli originating from the venous system reach the cerebral arterial circulation via the right-to-left (R-L) shunt. In patients with PCE, emboli originating from the venous system most commonly pass through the patent foramen ovale during Valsalva-provoking activities which increase the right atrial pressure above the left atrial pressure. The size of cerebral infarction caused by PCE is generally small, since the size of emboli which can pass through the R-L shunt is small. Here, we report a case of PCE which occluded the internal carotid artery (ICA).     

Gas flow during bronchoscopic ablation therapy causes gas emboli to the heart: a comparative animal study

BACKGROUND: Thermal ablation is one of the most commonly used modalities to treat central airway obstruction. Both laser and argon plasma coagulation (APC) have been reported to cause gas emboli and cardiac arrest. We sought to determine whether bronchoscopic ablation therapy can result in systemic gas emboli, correlate their presence with the rate of gas flow, and establish whether a zero-flow (ZF) modality would result in the significant reduction or elimination of emboli. METHODS: CO(2) laser delivered through a photonic bandgap fiber (PBF) and APC were applied in the trachea and mainstem bronchi of six anesthetized sheep at varying dosages and gas flow rates. Direct epicardial echocardiography was used to obtain a four-chamber view and detect gas emboli. RESULTS: The presence of gas flow accompanying APC and the CO(2) laser with forward flow correlated significantly with the appearance of gas bubbles in the atria. A definite dose response was observed between the gas flow rate and the number of bubbles seen. When the CO(2) laser was delivered through a PBF with ZF to the trachea or bronchi, no bubbles were observed. CONCLUSION: Bronchoscopic thermal ablation therapy using gas flow is associated with gas emboli in a dose-dependent fashion. The use of the flexible PBF with ZF is not associated with the development of gas emboli. Further study is required to determine whether a clinically safe threshold of gas emboli exists, and the relationships among the pathologic depth of tissue destruction, gas flow, pulse duration, and the development of gas emboli.     

Cerebral microvascular responses to air embolism-reperfusion in the cat using fluorescence videomicroscopy

Cerebral microvascular changes due to air embolism-reperfusion in the cat were investigated. Air embolism-reperfusion was produced in the cerebral microvessels by an intra-carotid injection of air (0.2-0.3 ml). Air emboli in the cerebral arterioles were observed continuously from the air injection to reperfusion using fluorescence videomicroscopy. Arteriolar diameter was measured based on video images of arterioles filled with rhodamine-B isothiocyanate dextran, and red cell velocity was measured using a dual window technique with FITC-labeled red cells. Air bubbles ceased to move in the arterioles of 20-70 microm diameter and blood flow was almost stopped in distal arterioles. The air emboli were of cylindrical shape in the arterioles, with hemispherical end caps. The emboli progressed slowly at rates of 7-73 microm/sec and then flowed away. The air emboli induced ischemia-reperfusion with the ischemic duration of approximately 1 minute (10 sec-3 min) at the arteriolar level. Cerebral arterioles began to dilate after the formation of the air emboli and significantly dilated by approximately 50% after reperfusion. A transient increase in red cell velocity was observed after reperfusion. Arteriolar dilation and the increase in velocity led to a hyperemic response in arteriolar flow to ischemia-reperfusion.     

Small cell lung carcinoma presenting as acute cardiovascular collapse due to tumour cell embolisation

We present a case of small cell lung carcinoma causing acute cardiovascular collapse due to pulmonary tumour emboli. Although pulmonary tumour emboli may complicate a number of malignancies, this is rarely seen in cases of carcinoma of the bronchus. Patients suffering with pulmonary tumour emboli often have previous symptoms, and show progressive dyspnoea. To our knowledge there have been no reports of tumour emboli presenting acutely without any previous history of symptoms.     

Atherosclerotic lesions from the reduction of pulmonary emboli

Seventy-five intimal arterial thickenings (from 58 subjects) related to pulmonary emboli were examined. Many showed residua derived from the emboli (fibrin, platelets, haemosiderin) and proliferation of elastica and smooth muscle cells. Features resembling those of atherosclerosis were the frequent presence of extracellular lipid and apolipoprotein-B containing lipoproteins (LpB) which corresponded closely in distribution; and (in about 40% of the thickenings) collections of fat-filled (foam) cells. Platelet antigens were often detected within foam cells in some cases, in company with LpB. The results indicate that at least some intimal thickenings originating from pulmonary emboli undergo transformation to atherosclerotic plaques. The role of pulmonary hypertension in the process was investigated. Mechanisms relevant to this transformation and to theories of atherogenesis are discussed.     

不同层厚螺旋CT造影对周围肺动脉血栓显示的比较

目的 评价不同层厚CT肺动脉造影(CTPA)对周围肺动脉内肺栓塞栓子的显示情况,提高对周围性肺栓塞的诊断水平.方法 分析2005年9月至2006年10月连续纳入的97例急性肺栓塞患者CTPA图像,以0.625 mm层厚的原始横轴位图像为基准,在此基础上采用MIP技术重建1.25 mm、2.5 mm和5.0 mm层厚的3组图像,比较4组不同层厚CTPA图像对周围肺动脉内肺栓塞栓子的显示有无差异;评价观察者之间对4组不同层厚图像上周围肺动脉内肺柃塞栓子显爪的一致性.不同层厚组间肺动脉栓塞血管数之间比较采用卡方检验,组间观察一致性比较采用中k检验.结果 0.625 mm层厚原始轴位和1.25 mm、2.5 mm、5.0 mm层厚MIP图像的平均图像数分别为403、201、101和53幅;在显示肺段动脉血栓方面,仪5.0 mm层厚图像与另3组间有统计学差异(χ~2=60.099,P<0.01),但各组图像的观察者间的一致性很好(κ值从0.751到0.992);在显示哑段肺动脉血栓方面,0.625 mm层厚与1.25 mm层厚图像差异没有统计学意义(χ~2=1.051,P>0.05),明显优于2.5 mm和5.0 mm层厚图像(χ~2值分别为151.892和204.553,均P<0.01),但各组图像的观察者间的一致件较好(κ值为0.611～0.935).结论 重建1.25 mm层厚的图像与0.625 mm层厚的图像在显示周围肺动脉内的肺栓塞栓子方面具有同等的诊断效能,与此同时可以减少图像的重建数量和阅读时间.     

Early surgery or medical treatment in endocarditis complicated by embolism from a large, mobile vegetation? A case-based discussion

Patients with endocarditis who present after embolism from a large, mobile vegetation pose a clinical dilemma: should they be managed with early surgery with the aim of preventing further emboli, or should a medical strategy be employed that avoids the morbidity and mortality associated with surgery but which risks further emboli? The management of such a patient is discussed in the context of the published literature regarding embolic risk in endocarditis.