Simulated flow pattern in massive pulmonary embolism: Significance for selective intrapulmonary thrombolysis

Purpose: The flow pattern in the central pulmonary arteries proximal to large pulmonary emboli was studied experimentally. The currents to which thrombolytic agents are exposed when administered via an intrapulmonary catheter were visualized in order to explain the lack of benefit of local versus systemic administration. Methods: By illumination of suspended microspheres, the flow pattern proximal to an obstructing embolus was visualized in an in vitro pulmonary arterial flow model. In six dogs massive pulmonary embolism was created. A pigtail catheter was positioned in the pulmonary artery immediately proximal to the central edge of the occluding embolus. To allow visualization of the local flow pattern, a small amount of contrast material (4 ml) was injected through the catheter at a high flow rate (25 ml/sec). The course of the radiopaque spot that emerged from the catheter tip within 160 msec was monitored with digital subtraction angiography at a frame rate of 12.5 frames/sec. In two dogs, the study was repeated after embolus fragmentation with the same catheter position. Results: The flow model study revealed formation of a vortex proximal to the occluding embolus. In vivo experiments showed that the radiopaque spot was whirled by the vortex proximal to the embolus and made only evanescent contact with the edge of the embolus. Regardless of the embolus location, the contrast spot was washed into the non-occluded ipsilateral and contralateral pulmonary arteries within 0.40–0.64 sec. After embolus fragmentation, the contrast spot was carried completely into the formerly occluded artery. Conclusion: Flow studies explain why thrombolytic agents administered via a catheter positioned adjacent to the embolus may have no more effect than systemically administered agents. An enhanced local effect is precluded by the rapid washout into the non-occluded pulmonary arteries and subsequent systemic dilution. These results support the practice of direct intrathrombic injection of thrombolytics or local thrombolysis as an adjunct to embolus fragmentation.     

Hybrid treatment with angiographic catheter in massive pulmonary embolism: mechanical fragmentation and fibrinolysis

PURPOSE: Massive pulmonary embolism is a severe clinical condition that requires prompt therapeutic intervention. We report our experience with a hybrid treatment involving systematic fragmentation of the embolus with an angiographic catheter associated with fibrinolytic therapy over the following days. MATERIALS AND METHODS: From 1999-2005 we treated 164 patients with massive pulmonary embolism. We used the same angiographic catheter for mechanical fragmentation and for administration of the fibrinolytic agent (24-72 h). Results were assessed on the basis of changes in mean pulmonary artery pressure. RESULTS: After fragmentation with the angiographic catheter, we observed four types of haemodynamic behaviour: in 61 patients (41.4%), mean pulmonary artery pressure fell rapidly below 30 mmHg; in 38 patients (23.1%), two passes were required to achieve the same result; in 32 patients (19.5%) three passes were required. In the remaining 26 patients (15.8%), at no time did the mean pulmonary artery pressure fall below 35 mmHg. The only two deaths occurred in this last group. CONCLUSIONS: Mechanical fragmentation with the angiographic catheter and administration of fibrinolytic agents effectively brought about a rapid improvement in patients' clinical status by moving the embolus towards the periphery.     

Endovascular covered stent repair of an iatrogenic subclavian artery-to-pulmonary artery fistula and pseudoaneurysm

An iatrogenic fistula and consequent pseudoaneurysm developed between the right subclavian artery and right pulmonary artery as a result of misplacement of a hemodialysis access catheter. The patient, who was considered to be at high risk for surgical repair, successfully underwent endovascular treatment that involved insertion of two nitinol stents covered with expanded polytetrafluoroethylene (stent-grafts), one into the right subclavian artery and the other into a right upper lobe pulmonary artery. Multi-detector row computed tomographic angiography played an integral role in the evaluation of the patient's vascular injury and treatment planning.     

Percutaneous fragmentation of pulmonary emboli in dogs with the impeller-basket catheter

A new catheter system for rapid percutaneous fragmentation of pulmonary emboli was tested in nine dogs. The system consisted of a high-speed rotating impeller, placed within the center of a self-expandable basket. Preformed radiopaque emboli were introduced via the right external jugular vein. In nine tests in five dogs, a single embolus was launched after the right pulmonary artery had been balloon occluded and the impeller-basket catheter had been positioned into the left pulmonary artery, Seven of nine emboli were completely fragmented, each within less than 10 s. In two tests, performed in two different dogs, the catheter was positioned after complete embolization of the left pulmonary artery. In both cases, the central pulmonary arteries could be fully, and the segmental arteries partly, recanalized. Mobility of the system within the pulmonary arteries was limited. There was no evidence of wall damage at the rotation site of the impeller. Free serum hemoglobin did not increase after treatment. We conclude that the device can be safely operated in the left pulmonary artery system of dogs. It causes no significant hemolysis, and is able to accomplish rapid recanalization of the central arteries. Due to limited steerability, occluded side branches cannot be treated consistently.     

Hybrid treatment of acute massive pulmonary thromboembolism: mechanical fragmentation with a modified rotating pigtail catheter, local fibrinolytic therapy, and clot aspiration followed by systemic fibrinolytic therapy

OBJECTIVE: We sought to evaluate the efficacy and safety of a hybrid treatment for acute massive pulmonary thromboembolism in patients with hemodynamic impairment by combining mechanical fragmentation, local thrombolysis, and clot aspiration. SUBJECTS AND METHODS: Within a period of 35 months, 25 patients with hemodynamic impairment (eight men and 17 women; age range, 35-77 years) were treated with mechanical thrombus fragmentation using a modified rotating pigtail catheter. After embolus fragmentation, all patients received an intrapulmonary injection of recombinant human-tissue plasminogen activator and then underwent manual clot aspiration with a large-lumen percutaneous transluminal coronary angioplasty guide catheter. RESULTS: All the patients survived, and their clinical status improved. Posttreatment angiography showed an improvement in pulmonary perfusion in all patients (mean Miller score before treatment, 22.2; after treatment, 13.6; p < 0.01). Mean pulmonary artery pressure decreased from 32.6 to 23.4 mm Hg (p < 0.01). Mean treatment time was 124.6 min. CONCLUSION: Hybrid treatment with mechanical fragmentation using a rotating pigtail catheter combined with local fibrinolysis and manual clot aspiration resulted in a rapid and safe improvement in the hemodynamic condition of patients with acute massive pulmonary thromboembolism. This hybrid treatment appears to be especially useful in patients at high risk for right ventricular failure and is a minimally invasive alternative to surgical embolectomy.     

New device for percutaneous fragmentation of pulmonary emboli

A new catheter system was designed for percutaneous fragmentation of large pulmonary emboli. The device consists of an impeller rotating at high speed at the center of a self-expandable basket at the tip of a 7-F catheter. The highly flexible catheter was able to reach all tested embolus sites in a glass model of the pulmonary arterial tree. Embolus fragmentation was quick and thorough. Particles in the effluent larger than 10 microns accounted for only about 9% of the treated embolus weight. Wall contact with the rotating impeller was not observed. The impeller-basket catheter promises to be a useful tool for percutaneous treatment of acute pulmonary embolism.     

Coronary artery to pulmonary artery collaterals in nonspecific aortoarteritis involving the pulmonary arteries

We report a patient with nonspecific aortoarteritis (Takayasu's disease) in whom occlusion of the right upper lobe pulmonary artery was associated with collateral flow from the left circumflex coronary artery. Coronary to pulmonary artery collaterals are rare in this disease but have important clinical implication because of their ability to produce coronary steal and myocardial ischemia. Awareness of these pathways is essential for their detection in patients with angina-like symptoms and for differentiation of myocardial ischemia due to direct coronary artery involvement by this disease.     

The vascular converging points of the right pulmonary hilus and their diagnostic significance

The shadows of the right descending pulmonary artery, the superior pulmonary vein crossing it, the middle lobe artery, and branches of the artery supplying the superior segment of the lower lobe converge distinctly at the right hilus. Because the right pulmonary artery bifurcates within the mediastinum, the arteries of the right upper lobe form a second though less obvious converging point above this level. In contrast, the left pulmonary artery does not bifurcate until it reaches the left hilus, providing only a single converging point on that side. A survey of 100 chest radiographs showed that the two converging points on the right could be distinguished in 95 cases, with the upper one being situated somewhat above the single point on the left in 83. In the absence of lobar resection, finding only one converging point on the right is suggestive of collapse of either the upper or lower lobe, whereas visualization of both points excludes major atelectasis.     

Laboratory Investigations[cmFragmentation of Pulmonary Emboli: In Vivo Experimental Evaluation of Two High-Speed Rotating Catheters

Purpose: To test two over-the-wire systems for fragmentation of pulmonary emboli. Methods: In 11 dogs, 22 embolic occlusions of lobar or central pulmonary arteries were performed by injection of preformed emboli through a jugular vein sheath. A commercially available device (thrombolizer) and a modified version of the impeller catheter were introduced via the femoral vein and positioned at the embolus site. Results: Catheter placement at the site of the emboli was possible. In more than half of the cases a hydrophilic or an extra-stiff guidewire was necessary. The thrombolizer did not rotate properly with its original pneumatic drive and required a major modification. When sufficient rotation was provided, both fragmentation catheters were able to clear the occluded main arteries. Side branches were partly obstructed by the resulting fragments. Recanalization led to a reduction of the emboli-induced elevation of the pulmonary arterial pressure by two-thirds. Histology of the recanalized pulmonary artery segments revealed localized (impeller catheter) and widespread (thrombolizer) periarterial hemorrhage. Conclusion: Embolus fragmentation led to a hemodynamic improvement. The impeller catheter was less traumatic compared with the thrombolizer, which was technically insufficient.     

Communicating arcade between the right and left hepatic arteries: evaluation with CT and angiography during temporary balloon occlusion of the right or left hepatic artery

PURPOSE: To evaluate prospectively the relationship between the arterial collateral system at the hepatic hilum and the blood supply to the hilar bile duct by using computed tomography (CT) and angiography during temporary balloon occlusion of the right or left hepatic artery. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The study included 13 patients with no lesions at the hepatic hilum (eight men and five women; age range, 41-78 years; mean, 65.8 years). After serial angiographic studies were performed for preoperative evaluation or transcatheter arterial chemoembolization, a 5.5-F catheter with an occlusion balloon was positioned in the right or left hepatic artery. Eleven patients underwent angiography of the left hepatic artery with temporary occlusion of the right hepatic artery, and two patients underwent angiography of the right hepatic artery with temporary occlusion of the left hepatic artery. In addition, 11 patients underwent single-level dynamic CT during hepatic arteriography (CTHA) with temporary occlusion of the right or left hepatic artery. The images from angiography and CTHA were interpreted by two authors who assessed the existence of the arterial communication and its branching points, location, and relationship to the hilar bile duct and caudate lobe. RESULTS: During temporary occlusion of the right or left hepatic artery, the communicating arcade (CA) between the right and left hepatic arteries was immediately evident in all patients. On the left side, the CA originated from the segment IV artery in eight patients (62%) and from the left hepatic artery in five (38%). On the right side, the CA originated from the right anterior hepatic artery in six patients (46%), the right hepatic artery in two (15%), and both arteries in five (38%). The CA was extrahepatically located close to the hilar bile duct and forked into a few branches to the caudate lobe. CONCLUSION: The CA may play an important role not only in the interlobar arterial collateral system but also in the blood supplies to the caudate lobe and hilar bile duct.     

False-positive lung imaging: inadvertent injection into a pulmonary artery catheter.

A case of a ventilation-perfusion mismatch seen post-operatively in a patient with chest pain is reported. There was absence of perfusion to the right lung, with relatively normal ventilation. The study was initially interpreted as indicating a high probability of pulmonary embolus. It was then discovered that the injection had been inadvertently made into a Swan-Ganz catheter, with its tip in the left main pulmonary artery. The mismatch was therefore iatrogenic and not related to pulmonary embolus. The false-positive lung imaging which resulted has not been previously reported in the literature.     

Postmortem computed tomography evaluation of fatal gas embolism due to connection of an intravenous cannula to an oxygen supply

An 84-year-old man who had suffered from chronic obstructive pulmonary disease accompanied by moderate pneumonia as well as gastric cancer with liver metastasis was found dead by a nurse, who noticed that the patient’s intravenous catheter in the left forearm had been erroneously connected to an oxygen supply in his hospital room, leading to infusion of oxygen into a vein. Postmortem CT scanning demonstrated multiple accumulations of gas in the pulmonary artery, the right atrium and ventricle, as well as the left subclavian and brachiocephalic veins, corresponding to the route that the infused gas would have taken to the heart and pulmonary artery. Conventional autopsy revealed the presence of gas in the right ventricle. These findings suggested that the immediate cause of death was a gas embolus due to oxygen that had entered the cardiopulmonary circulation via the intravenous catheter. This case highlights the usefulness of postmortem imaging as an aid to conventional autopsy for demonstrating gas embolism.     

Behavior of the blood vessels of the lung on the roentgen image in children with bronchial asthma--determination of the width of the blood vessels

On x-ray films of 51 children with asthma bronchiale the authors determined the vascular diameter of the right ascending pulmonary artery, the right vein of the upper lobe, and the peripheral vessels in the upper and lower pulmonary fields at an exactly defined distance from the hilus point, and compared these data with those of a control group of 143 healthy children. During the asthma attack the width of the right descending pulmonary artery and of the vein of the upper lobe corresponded to the values of the control group, whereas the vascular diameters in the upper and lower fields were clearly narrowed. Moreover, in most of the asthmatic children the authors found arc-shaped vessels and irregularly occluded vessels in the periphery of the lungs.     

Transcatheter wiring of abdominal aortic aneurysm

A new technique of transcatheter wiring of unresectable aortic aneurysm is described that provides simultaneous transcatheter occlusion of both common iliac arteries followed by axillofemoral bypass. The spring coil used for aortic aneurysm wiring was of our own making. The outer portion of a movable core stainless steel guidewire was bent in a coil shape and introduced into the aneurysm through a 7 French Teflon catheter via the right femoral artery. The same catheter was also used for coil embolus occlusion of both iliac arteries.     

肺动脉吊带的影像学诊断

目的 评价肺动脉吊带的影像学诊断价值。方法 7例肺动脉吊带中5例做了心血管造影（ACG）（5例均做了MR检查，4例同时做了CT检查），2例仅做MR检查。结果 7例肺动脉吊带病例中6例显示左肺动脉起始于右肺动脉远端分叉部，并绕过气管后方（4例有气管压迫征象，临床有气急、喘鸣的症状），另有1例为左下肺动脉起始于右肺动脉远端近分叉处，左上肺动脉起始正常。5例经手术证实。结论 ACG、造影增强磁共振血管造影（CE-MRA）、CT血管造影（CTA）为明确肺动脉吊带诊断的最佳方法，3种方法可互为补充。心血管造影选择性强，CE-MRA的三维成像显示肺动脉的走向较有优势；CTA可以同时显示气管和异常起源的左肺动脉之间的关系。     

Direct percutaneous transluminal angioplasty for acute middle cerebral artery occlusion.

PURPOSEWe review our initial experience with direct percutaneous transluminal angioplasty (PTA) as a reperfusion treatment for acute occlusion of the middle cerebral artery.METHODSTen patients in whom successful thrombolysis might not be expected because of the risk of hemorrhagic complications or reocclusion were treated with direct PTA. When early ischemic findings were present on the initial CT scans and/or when lenticulostriate arteries were involved, we performed direct PTA rather than thrombolytic therapy. Direct PTA was also performed when superselective local angiography via a Tracker catheter advanced just distal to the occlusion site showed the presence of a large embolus or high-grade stenosis suggestive of thrombosis. Angioplasty was performed with a Stealth balloon catheter with a maximum diameter of 2.0 to 2.5 mm. The balloon catheter was advanced into the site of occlusion and inflated to 2 atm initially, and subsequently up to 3 atm. Two to six inflations, each of 30 seconds'' duration, were performed.RESULTSAlthough the rate of initial recanalization was 100% (10 of 10), reocclusion occurred in two patients with atherothrombotic M2 occlusion. The final angiographic success rate of direct PTA was 80% (8 of 10). There were no hemorrhagic or technical complications, and five of 10 patients showed marked clinical improvement. In two of seven patients with cardioembolic M1 trunk occlusion, crushed fragments of the embolus obstructed M2 portions after direct PTA, necessitating local thrombolysis.CONCLUSIONDirect PTA may be performed safely as an alternative to thrombolytic therapy in patients with acute occlusion of the middle cerebral artery when early CT findings and/or lenticulostriate artery involvement are present or when superselective local angiography shows the presence of a large embolus or high-grade stenosis.     

Transcatheter embolization for huge pulmonary arteriovenous fistula using metallic "spider" and spring embolus--application of hand-made metallic "spider" using partial monorail technique]

We performed transcatheter embolization in two cases with huge pulmonary arteriovenous fistula (AVF) using a metallic "spider" and spring embolus. Conventional spring embolus or detachable balloon could not be used in these cases. Metallic spider was indicated for pulmonary AVF with a feeding artery diameter of more than 16 mm to prevent embolus passing through the AVF. In the first case, we used large handmade metallic spiders of 25 mm in diameter followed by embolization by numerous spring coils. At that time, a partial monorail technique was newly devised to carry the large metallic spider into the feeding artery, otherwise the spider could not pass into a 9F catheter. After embolization, symptoms and PaO2 in arterial blood improved remarkably in both cases. In the second case, a spring coil migrated into the normal pulmonary artery, but no infarction resulted. In conclusion, the metallic spider was very useful for embolization of hugee pulmonary AVF to avoid the embolus passing through and to tangle spring coils together with it. If commercially available "spiders" are too small, ones can be made easily.     

SPECT/CT肺灌注显像中肺段精确定位方法的研究

目的 研究SPECT/CT肺灌注显像中肺段横断面、矢状面及冠状面的精确定位方法.方法 分析12名健康成人的肺灌注断层图像、CT图像及二者的融合图像,按CT解剖命名标准对肺灌注横断面、矢状面及冠状面图像上肺段进行划分.即右肺10段:上叶尖段、后段、前段,中叶外侧段、内侧段,下叶背段、内基底段、前基底段、外基底段、后基底段;左肺8段:上叶尖后段、前段、上舌段、下舌段,下叶背段、前内基底段、外基底段、后基底段,并总结3个层面肺段分布的特点.结果 确定了左右肺在横断面、矢状面及冠状面上的典型层面及各个肺段的主要分布特点:(1)横断面双肺由肺尖至肺底选取11个层面:胸锁关节层面及以上,主动脉弓上缘层面,主动脉弓层面,奇静脉弓层面或气管杈层面,右肺上叶支气管层面或左肺动脉层面,左肺上叶支气管层面或右肺动脉层面,中叶或舌叶支气管层面,底干支气管层面,下肺静脉层面,上下底段静脉层面,底段静脉层面;(2)双肺由内向外分别选取6个层面,左肺:左肺门层面,左主支气管杈层面,左肺动脉叶间部层面,心尖层面,心尖左侧第一层面,心尖左侧第二层面;右肺:右肺门层面,中间支气管杈层面,叶间动脉层面,叶间动脉分杈层面或右心房右侧第一层面,右心房右侧第二层面,右心房右侧第三层面向外;(3)冠状面双肺由前向后选取7个层面:胸锁关节层面,升主动脉层面,肺动脉杈层面,气管杈层面,中间支气管层面,底段总静脉层面,胸主动脉层面.结论 按该研究方法划分肺段,可为肺灌注断层图像中肺段的精确定位提供参考依据.     

Upper lung lobe systemic artery-pulmonary vein fistula with signs and symptoms of congestive heart failure: successful treatment with coil embolization

Systemic artery-pulmonary vein fistula with a pulmonary left-left shunt is extremely rare. In this report, we present the case of a 3-month-old infant with enlarged right upper lobe systemic artery-pulmonary vein fistula and signs and symptoms of vascular tracheal compression and congestive heart failure. Two major aberrant arteries with separate origins came from the descending thoracic aorta and entered the right upper pulmonary lobe where they branched into many vascular channels and promptly drained into the enlarged right upper pulmonary vein. One of the two aberrant arteries was successfully coil embolized, and the other aberrant artery spontaneously closed after cardiac catheterization.     

SPECT/CT肺灌注显像中肺段精确定位方法的研究

目的 研究SPECT/CT肺灌注显像中肺段横断面、矢状面及冠状面的精确定位方法.方法 分析12名健康成人的肺灌注断层图像、CT图像及二者的融合图像,按CT解剖命名标准对肺灌注横断面、矢状面及冠状面图像上肺段进行划分.即右肺10段:上叶尖段、后段、前段,中叶外侧段、内侧段,下叶背段、内基底段、前基底段、外基底段、后基底段;左肺8段:上叶尖后段、前段、上舌段、下舌段,下叶背段、前内基底段、外基底段、后基底段,并总结3个层面肺段分布的特点.结果 确定了左右肺在横断面、矢状面及冠状面上的典型层面及各个肺段的主要分布特点:(1)横断面双肺由肺尖至肺底选取11个层面:胸锁关节层面及以上,主动脉弓上缘层面,主动脉弓层面,奇静脉弓层面或气管杈层面,右肺上叶支气管层面或左肺动脉层面,左肺上叶支气管层面或右肺动脉层面,中叶或舌叶支气管层面,底干支气管层面,下肺静脉层面,上下底段静脉层面,底段静脉层面;(2)双肺由内向外分别选取6个层面,左肺:左肺门层面,左主支气管杈层面,左肺动脉叶间部层面,心尖层面,心尖左侧第一层面,心尖左侧第二层面;右肺:右肺门层面,中间支气管杈层面,叶间动脉层面,叶间动脉分杈层面或右心房右侧第一层面,右心房右侧第二层面,右心房右侧第三层面向外;(3)冠状面双肺由前向后选取7个层面:胸锁关节层面,升主动脉层面,肺动脉杈层面,气管杈层面,中间支气管层面,底段总静脉层面,胸主动脉层面.结论 按该研究方法划分肺段,可为肺灌注断层图像中肺段的精确定位提供参考依据.