Angioplastia percutánea con balón en hipertensión pulmonar tromboembólica crónica / Percutaneous balloon angioplasty for treatment of chronic thromboembolic pulmonary hypertension

La hipertensión pulmonar tromboembólica crónica se caracteriza por la presencia de material trombótico organizado dentro de las arterias pulmonares que genera elevación de la resistencia vascular pulmonar, insuficiencia cardíaca derecha y, eventualmente, la muerte. El tratamiento de elección es la tromboendarterectomía pulmonar, que suele ser curativa si la obstrucción es proximal. En algunos casos este tratamiento no es posible y surge como alternativa la angioplastia pulmonar con balón (APB), que está generando creciente interés. Se presentan tres casos de pacientes con hipertensión pulmonar tromboembólica a los que por diferentes circunstancias no pudo tratarse con tromboendarterectomía y se realizó APB comprobándose, en los tres casos, mejoría de la clase funcional, prueba de la caminata de seis minutos, además de parámetros hemodinámicos y angiográficos.

Chronic thromboembolic pulmonary hypertension is characterized by the presence of organized thrombotic material in the pulmonary arteries which causes elevation of the pulmonary vascular resistance, right heart failure, and death if not treated. Pulmonary thromboendarterectomy is the treatment of choice and can be curative when the obstruction is proximal. There are cases in which this therapy is not possible, and pulmonary angioplasty is a therapeutic alternative of growing interest. We present our experience with three patients diagnosed with chronic thromboembolic pulmonary hypertension in whom pulmonary endarterectomy was not possible and pulmonary angioplasty was performed. All patients showed improvement of functional class, six-minute walk distance, and hemodynamic as well as angiographic parameters.

Retrograde Tempofilter II(TM) Placement within the Superior Vena Cava in a Patient with Acute Upper Extremity Deep Venous Thrombosis: the Filter Stands on Its Head

The Tempofilter II is a widely used temporary vena cava filter. Its unique design, which includes a long tethering catheter with a subcutaneous anchor, facilitates the deployment and retrieval of the device. Despite this, the Tempofilter II has been used only in the inferior vena cava of patients with lower extremity deep venous thrombosis. In this article, we present a case of superior vena cava filtering using the Tempofilter II in patients with upper extremity deep venous thrombosis.

Comparison of the CT and Pathologic Findings of Pulmonary Fat Embolism Induced by Triolein and Oleic Acid in Rabbits

PURPOSE: The aim of this study was to evaluate the CT findings of pulmonary fat embolism syndrome that was induced by triolein and oleic acid, along with its pathologic correlation. MATERIALS AND METHODS: 16 rabbits were included in this study. The rabbits in group I (n=8) were embolized with 0.2 mL triolein and the rabbits of group II (n=8) were embolized with 0.2 mL oleic acid through ear veins. HRCT scans were done prior to embolization and at 0.5, 4, 24, 48 and 72 hours post-embolization. The pathologic correlations were determined at 0.5, 24, 48 and 72 hours. RESULTS: At 24 hours, one group I rabbit showed abnormal CT findings that were composed of several 2-3 mm nodules and multiple ill-defined peripheral ground glass opacities. The pathologic finding of this rabbit at 48 hours was mainly intraarveolar edema. All the group II rabbits (n=8/8) showed ill-defined bilateral and peripheral ground glass opacities with (n=6/8) or without consolidations (n=2/8) on the 0.5 hour CT. All the rabbits (n=7/7) showed that the new ground glass opacities and ground glass opacities noted on the 0.5 hour CT were changed into consolidation. The margins of the ground glass opacities and consolidations were more sharpened on the 24 hours CT. All 6 rabbits (n=6/6) showed consolidations without ground glass opacities and the margins of the consolidations were more sharpened on the 48 hours CT. There was no significant interval change on the 72 hours CT. The pathologic findings of ground glass opacities were interstitial edema or mild intraalveolar edema. The pathologic findings of consolidation were intraalveolar edema, hemorrhage and coagulation necrosis. CONCLUSION: The CT findings after fat embolization using triolein and oleic acid were ill-defined peripheral ground glass opacities with/without consolidations. These findings occurred in only one triolein group with the time lag, but these findings were immediately and extensively seen in all group II rabbits. These CT findings may be important for making a diagnosis of pulmonary fat embolism syndrome.

Acrylic Cement Foreign Body and Thrombus in Right Atrium Causing Pulmonary Embolism after Percutaneous Vertebroplasty

A pulmonary embolism is a rare, but well described complication of percutaneous vertebroplasty; the majority of cases are caused by acrylic cement. Here, for the first time, we report a case of pulmonary embolism due to a thrombus in the right atrium, which was caused by an acrylic cement foreign body in the right atrium and central veins 6 years after percutaneous vertebroplasty. This case suggests that an acrylic cement foreign body should be considered as a potential source of thrombus formation in patients that develop a pulmonary embolism following percutaneous vertebroplasty.

Massive Tumor Pulmonary Embolism Following Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma

Pulmonary embolism complicated by transcatheter arterial chemoembolization (TACE) is known to be due to the use of large amount of lipiodol as an embolic agent. To our knowledge, massive tumoral pulmonary embolism following TACE and confirmed by surgery has not been described in the literature. In this report, we detail the case of a 49-year-old man in whom cyanosis and hypotension developed abruptly on the day of TACE. Chest CT revealed diffuse low-attenuated lesions in both pulmonary arteries. Histopathological specimens after emergent pulmonary arterial embolectomy confirmed the presence of massive tumor emboli of hepatocellular carcinoma.

An Experimentally Induced Fat Embolism in the Rabbit Lung: High-resolution CT and Pathologic Findings

PURPOSE: To assess the high-resolution CT and pathologic findings of fat embolism experimentally induced in rabbit lung. MATERIALS AND METHODS: Twelve rabbits were divided into four groups, namely control, 2-hour, 24-hour, and 72-hour, with three rabbits in each, and closed tibiofibular fractures were induced. After the rabbits were sacrificed, high-resolution CT scanning of the artificially inflated lungs was performed, and the CT findings were analyzed by two radiologists. They determined the presence or absence of ground glass opacity or consolidation, the extent of the lesions (using a 10% grading scale), and their distribution, reaching a consensus. The pathologic findings were analyzed using the specimens prepared by H & E and Oil-red O staining. RESULTS: Although the high-resolution CT findings of pulmonary fat embolism were nonspecific, bilateral patchy ground glass opacity (100%), and focal air-space consolidation surrounding the bronchovascular bundle (89%) were most common. In all groups, the occlusion of vessels by fat globules was confirmed by Oil-red Ostaining. The microscopic findings included focal pulmonary hemorrhage, edema, alveolar collapse, and extensive infiltration of inflammatory cells in the lung parenchyma. The 24-hour group showed more extensive change in high-resolution CT and pathologic findings than did the others. CONCLUSION: Fat embolism in rabbit lung may occur after closed tibio-fibular fracture. The extent of the lesion revealed by high-resolution CT correlated closely with the pathologic findings. High-resolution CT may thus be helpful for the detection of pulmonary fat embolism and evaluation of its extent.

Titanium Greenfield Inferior Vena Cava Filter: Effectiveness of Percutaneous Placement for Prevention of Pulmonary Embolism

PURPOSE: To evaluate the effectiveness of percutaneous placement of a Greenfield titanium filter in the inferior vena cava (IVC) for the prevention of pulmonary embolism (PE) in patients with deep vein thrombosis (DVT). MATERIALS AND METHODS: Twelve patients with DVT underwent percutaneous Greenfield titanium filter placement. The indications included recurrent pulmonary embolism or failed anticoagulation therapy in six patients, extensive PE in three, and prophylaxis for high risk of PE in the remaining three. In all cases the filter was positioned after confirming the anatomy, patency, and presence of thrombosis of the IVC and renal veins by inferior vena cavography. Long-term follow-up study involved clinical evaluation, plain radiography, Doppler ultrasonography and CT scanning. RESULT: Filter placement [infrarenal in ten patients (83%) and suprarenal in two (17%)] was technically successful in all cases (100%). The venous approach involved the right femoral vein in eight patients (67%) and the right internal jugular vein in four (33%). Complications included overlapping of the filter legs in three patients (25%), and misplacement in one (8%). After filter placement, no further PE developed. In all of five patients followed up for two years, the IVC maintained patency without evidence of caval perforation or occlusion. CONCLUSION: In patients with DVT, percutaneous placement of a Greenfield titanium filter is a safe and effective method for the prevention of PE.

Low Attenuation on High Resolution Computed Tomography in Pulmonary Embolism: An Experimental Study in Pigs

PURPOSE: To evaluate the incidence and type of low attenuation seen on high resolution computed tomography (HRCT) performed after artificially induced pulmonary embolism. MATERIALS AND METHODS: Using permanent embolic materials, pulmonary embolism was induced in ten Yorkshire pigs. Pre- and postembolic pulmonary angiography was performed, and HRCT was performed immediately and 1, 3, and 6 weeks after embolization. The incidence and type of low attenuation of all segments, as seen on HRCT, was evaluated. Low attenuation was classified as mottled, lobular, segmental, or peripheral. The pigs were sacrified after 6 weeks and contact radiographs were obtained. RESULTS: Low attenuation developed in eight of ten pigs. Pulmonary angiography revealed arterial occlusion in 15 large and 19 small segmental arteries (34 of 45 segments). In the remaining 11 segments, follow-up HRCT demonstrated areas of low attenuation. This was present in 25 of 35 segments (71%) as seen on HRCT images obtained immediately; in 16 of 41 segments (39 %) on images obtained 1 week after embolization; in 17 of 41 segments (41 %) on those acquired at 3 weeks; and in 25 of 45 segments (56 %) on those acquired at 6 weeks. The overall incidence of low attenuation was 83/166 (50 %). The types of low attenuation were mottled in 32/83 cases, lobular in 13/83, segmental in 13/83, and peripheral in 25/83. In large segmental arterial occlusion, the incidence of low attenuation on HRCT was 100% immediately, 57% at 1 week, 60% at 3 weeks, and 80 % at 6 weeks. In small segmental arterial occlusion, the incidence was 47%, 25 %, 11 %, and 21 % respectively. The overall incidence of low attenuation was 40/55 (73 %) in large segmental arterial occlusion and 18/71 ( 25%) in small segmental arterial occlusion. CONCLUSION: Low attenuation on HRCT is a finding of pulmonary embolism and is more common on HRCT performed immediately after embolization (71%) and in large segmental arterial occlusion (73%). Low attenuation on HRCT is an ancillary finding and may be useful in the diagnosis of pulmonary embolism.