Pulmonary artery embolization

Eckart RE, Hmczkowski TW, Lanzberg MJ et al (2006) Pulmonary arterial embolization of pacemaker lead electrode tip. Pacing Clin Electrophysiol 29 784-787... 

Rare complications as have been reported in literature are aortic and bronchial necrosis [58], bronchial stenosis [59], unilateral diaphragmatic paralysis [60], pulmonary infarction (especially in patients who have suffered pulmonary artery embolism), left main bronchial-esophageal fistula [61], and non-target embolization (colon, coronary and cerebral circulation) [62]. Especially the newer spherical embolic materials (tris-acryl gelatin) can traverse from the bronchial into the pulmonary circulation, and then through unoccluded pulmonary arteriovenous malformations into the systemic circulation [41]. 

For some diagnostic tasks such as the search for small pulmonary artery embolism, it is necessary to reconstruct continuous thin slices to enable more sophisticated postprocessing. 

In general, arterial thrombi are platelet-rich ( white clots ) and form at ruptured atherosclerotic plaques, leading to intraluminal occlusion of arteries that can result in end-organ injury (e.g., myocardial infarction, stroke). In contrast, venous thrombi consist mainly of fibrin and red blood cells ( red clots ), and usually form in low-flow veins of the limbs, producing deep vein thrombosis (DVT) the major threat to life results when lower extremity (and, occasionally, upper extremity) venous thrombi embolize via the right heart chambers into the pulmonary arteries, i.e., pulmonary embolism (PE). 

Pulmonary hypertension develops late in the course of COPD, usually after the development of severe hypoxemia. It is the most common cardiovascular complication of COPD and can result in cor pulmonale, or right-sided heart failure. Hypoxemia plays the primary role in the development of pulmonary hypertension by causing vasoconstriction of the pulmonary arteries and by promoting vessel wall remodeling. Destruction of the pulmonary capillary bed by emphysema further contributes by increasing the pressure required to perfuse the pulmonary vascular bed. Cor pulmonale is associated with venous stasis and thrombosis that may result in pulmonary embolism. Another important systemic effect is the progressive loss of skeletal muscle mass, which contributes to exercise limitations and declining health status. 

Pulmonary embolism A disorder of thrombus formation causing obstruction of a pulmonary artery or one of its branches may result in pulmonary infarction. 

Venous thromboembolism (VTE) results from clot formation in the venous circulation and is manifested as deep vein thrombosis (DVT) and pulmonary embolism (PE). A DVT is a thrombus composed of cellular material (red and white blood cells, platelets) bound together with fibrin strands. A PE is a thrombus that arises from the systemic circulation and lodges in the pulmonary artery or one of its branches, causing complete or partial obstruction of pulmonary blood flow. 

Prophylaxis and treatment Prophylaxis and treatment of venous thrombosis and its extension pulmonary embolism peripheral arterial embolism atrial fibrillation with embolization. 

Treatment of venous thrombosis, pulmonary embolism, peripheral arterial embolism, atrial fibrillation with embolism Intermittently Initially, 10,000 units, then 50-70 units/kg (5000-10,000 units) q4 6h. IV Infusion Loading dose 80 units/kg, then 18 units/kg/hr, with adjustments based on aPTT. Range 10-30 units/kg/hr. 

Prevention of venous thrombosis, pulmonary embolism, peripheral arterial embolism, atrial fibrillation with embolism Subcutaneous 5000 units q8-12h. 

It is indicated in the prophylaxis and treatment of deep vein thrombosis in major surgery and pulmonary embolism, treatment of atrial fibrillation with embolisation, prophylaxis and treatment of peripheral arterial embolism. 

A red thrombus can form around a white thrombus as mentioned above or de novo in low-pressure veins, initially by adherence of platelets (as in arteries) but followed promptly by the process of blood coagulation so that the bulk of the thrombus forms a long tail consisting of a fibrin network in which red cells are enmeshed. These tails become detached easily and travel as emboli to the pulmonary arteries. Such emboli often arise from a deep venous thrombosis (DVT)—a thrombus in the veins of the legs or pelvis. Although all thrombi are mixed, the platelet nidus dominates the arterial thrombus and the fibrin tail the venous thrombus. Arterial thrombi cause serious disease by producing local occlusive ischemia venous thrombi, by giving rise to distant embolization. 

Embolism associated with long flights is generally due to thrombus formation in deep leg veins (deep-vein thrombosis, or DVT). The thrombus may move to the pulmonary circulation, where effects on lung function depend on the extent of the blockage produced. A massive embolus may occlude the main pulmonary artery, resulting in hypotension, shock and possibly death multiple small emboli cause little problem and are lysed by the fibrinolytic system. Sometimes surgical removal of the embolus is necessary, but in Pats/s case clot lysis was successful and she made an uneventful recovery. 

Weingarten J, Kauffman SL. Teflon embolization to pulmonary arteries. Ann Thorac Surg 1977 23(4) 371-3. 

Aberrant thrombus formation and deposition on blood vessel walls imderlies the pathogenesis of acute cardiovascular disease states which remain the principal cause of morbidity and mortality in the industrialized world [1,2,3]. Plasma proteins, proteases and specific cellular receptors that participate in hemostasis have emerged as important risk considerations in thrombosis and thromboembolic disorders. The clinical manifestations of the above disease states include acute coronary artery and cerebrovascular syndromes, peripheral arterial occlusion, deep vein thrombosis and pulmonary/renal embolism [3]. The most dilabilitating acute events precipitated by these disorders are myocardial infarction and stroke. In addition, the interplay between hemostatic factors and hypertension (4) or atherosclerosis (5) dramatically enhances the manifestation of these pathologic states. 

Venous thromboembolism, including thrombosis of the deep veins of the legs and embolism to the pulmonary arteries, is uncommon in the general population. The absolute risk of venous thromboembolism in non-hormone therapy users is approximately 1 in 10,000 women. Women taking hormone therapy have a twofold increase in risk for thromboembolic events, with the highest risk occurring in the first... 

Heparin is an anticoagulant that inhibits reactions that lead to clotting. It is indicated in prophylaxis and treatment of venous thrombosis and its extensions, pulmonary embolism (PE), peripheral arterial embolism, and atrial fibrillation with embolization diagnosis and treatment of acute and chronic consumption coagulopathies (DIC) and prevention of postoperative deep venous thrombosis. 

Venous (red) thrombi develop in areas of slow blood flow (e.g., leg veins of a bedridden patient). The clot forms rapidly and lacks the organization of the arterial thrombus. Venous occlusion occurs, but is not the primary damage caused by venous thrombi. More worrisome is the tendency of small pieces (emboli) to detach from venous thrombi and travel to pulmonary arteries. The emboh wedge into pulmonary arteries, prohibiting deoxygenated blood from entering the portion of the limg served by the embolized artery. 

Venous thromboembolism occurs when red bloods cells, fibrin, and to a lesser extent, platelets and leukocytes coagulate to form a thrombus within an intact cardiovascular system (9). A patient undergoing orthopaedic surgery incurs the greatest risk for VTE (10). Pulmonary embolism occurs when a segment of a thrombus within the deep venous system detaches itself from the blood vessel, travels to the lungs, and lodges within the pulmonary arteries. Both of these conditions, if not... 

Golzio PG, Bongiomi MG, Giuggia M et al (2007) Retrieval of pacemaker lead tip embolized into the distal pulmonary arterial bed during extraction procedure. Pacing Clin Electrophysiol 30 1558-1561... 

As is the case with most invasive procedures, deep venous thrombosis and pulmonary embolus represent rare but potential complications of the uterine artery embolization procedure [53]. Patients taking oral contraception are known to be at increased risk for venous thromboembolic disease and there may be a transient hypercoagulability after embolization [92-94],... 

There have been at least two deaths reported in association with massive pulmonary embolism disease after uterine artery embolization [95], While... 

In conclusion, uterine artery embolization is both a safe and effective procedure to offer patients with symptomatic uterine fibroids. UFE has been described as a valuable alternative to hysterectomy and recurrent multiple myomectomy. Clinical success rates for control of heavy menstrual bleeding, pelvic pain and bulk-related symptoms have been reported to be 80%-95% of patients treated with a low rate of recurrence. The risk of major complications, including pulmonary embolism, uterine... 

Ramakantan R, Bandekar VG, Gandhi MS, Aulakh BG, Deshmukh HL (1996) Massive hemoptysis due to pulmonary tuberculosis control with bronchial artery embolization. Radiology 200 691-694... 

Fig. 17.5a,b. Diffuse PAVMs. a CT obtained at the level of both lower lobes shows multiple PAVMs involving both lungs, b Selective injection of pulmonary artery to the middle lobe confirms that all segmental arteries supply small PAVMs. Note that multiple large PAVMs have already been embolization with coils... 

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