Pulmonary Embolism


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Pulmonary Embolism

  1. 1. <ul><li>Percutaneous rheolytic thrombectomy for large pulmonary embolism: A promising treatment option </li></ul><ul><li>Chauhan et al, CCI 2007; 70 : 123-130 </li></ul><ul><li> Background: Pulmonary embolism (PE) is a common cardiovascular disease with significant mortality. Some patients with large PE are not eligible for current treatment options such as thrombolysis or surgical embolectomy. We report our experience of percutaneous rheolytic thrombectomy (PRT) using the AngioJet system combined with adjunctive local thrombolytic therapy and inferior vena cava (IVC) filter placement to treat massive or submassive PE in patients ineligible for current treatment options. Methods and Results: Of the 14 consecutive patients ineligible for thrombolysis or embolectomy treated with PRT, 10 patients had massive PE (6 patients were hypotensive and 4 patients had intractable hypoxemia) and 4 patients had submassive PE. Adjunctive local thrombolysis was performed in 5 patients. An IVC filter was placed in 11 patients. Angiographic success based on Miller score was achieved in 13 patients (92.9%). Procedure success was obtained in 12 patients (85.7%). Procedural mortality occurred in one patient who presented in cardiogenic shock (7.1%) and non-fatal hemoptysis occurred in 1 patient (7.1%). Total in-hospital mortality occurred in 3 patients (21.4%). On a mean follow-up of 9 months, all 11 survivors had noted significant improvement in symptoms without recurrence. Conclusions: Percutaneous rheolytic thrombectomy using the AngioJet may be a treatment option for patients with massive or submassive PE who may not be eligible for thrombolytic therapy or surgical embolectomy. © 2007 Wiley-Liss, Inc. </li></ul>
  2. 2. <ul><li>Current Treatment Options </li></ul><ul><li>Thrombolytic therapy for massive PE is associated with early reperfusion, decrease in pulmonary pressure, and limiting the extent of RV dysfunction. Randomized trials have suggested mortality benefit over heparin anticoagulation for major PE with hemodynamic instability [[ 13 ][ 21-24 ]]. Thrombolytic therapy is, however, associated with a significant risk of major bleeding (8%-22%), especially devastating intracranial bleeding (3%) [[ 2 ][ 25 ]]. Moreover, nearly 25-50% of patients with massive or submassive PE may be ineligible for systemic thrombolysis, limiting its use in the high-risk population [[ 13 ][ 14 ]]. On the other hand, surgical pulmonary embolectomy carries a substantial morbidity and mortality (40-50%), and despite the recent improvement in surgical outcomes, it is available only in few highly specialized centers [[ 26 ][ 27 ]]. </li></ul><ul><li>Endovascular Therapies </li></ul><ul><li>Since many patients with large PE are ineligible for systemic thrombolysis or surgical embolectomy, and swift restoration of pulmonary flow is essential for better outcomes, percutaneous thrombectomy is an appealing alternative. Different devices have been created and can be broadly divided into three categories based on their mechanisms of action: (a) mechanical fragmentation of the embolus using guide-wires, pigtail catheters, or balloons, (b) extraction using cup or basket devices, or (c) hydrodynamic fragmentation and aspiration of the embolus. To date, the Greenfield embolectomy device, the first and oldest device for this purpose, is the only device currently approved by the Food and Drug Administration (FDA) for treatment of PE. The device, however, has the disadvantage of requiring a 12-Fr vascular sheath, which was associated with increased risk of vascular complications [[ 8 ]]. </li></ul><ul><li>The AngioJet rheolytic thrombectomy system (Possis Medical, Minneapolis, MN) is an aspiration device, which uses the Bernoulli phenomenon, whereby a low-pressure zone is created around the catheter by the high-speed retrograde saline jet. This results in mechanical disruption, aspiration, and retrieval of the surrounding thrombus. The AngioJet thrombectomy device is widely used in the coronary and peripheral vasculature [[ 28 ][ 29 ]]. </li></ul><ul><li>PRT for PE Using AngioJet </li></ul><ul><li>Use of the AngioJet for the treatment of massive PE has been reported in 26 patients with large or massive PE who were ineligible for thrombolytic therapy in five published reports (Table III ) [[ 16-20 ]]. Intraprocedural complications were few but unique including bradycardia and massive hemoptysis; the latter occurred in three of the 26 reported technically successful cases. These problems have dampened enthusiasm for further development of this technique. </li></ul><ul><li>Our experience of treating 14 high-risk patients with massive or submassive PE with the AngioJet demonstrates high success and low complication rates. We attribute our improved technical success and reduced procedural complications (especially hemoptysis) to several factors including: 1Early recognition and treatment of high-risk patients with massive or submassive PE who are otherwise ineligible for systemic thrombolysis.2Emphasis on clot debulking to restore distal perfusion rather than clot resolution. Our endpoint was guided by improvement in distal perfusion, symptomatic improvement and hemodynamic stability rather than complete angiographic resolution of embolus. This strategy may also explain better outcomes by Voigtlander et al., who regarded improvement in perfusion as a more important endpoint rather than resolution of thrombus burden [[ 17 ]].3Judicious use of a temporary pacemaker. </li></ul><ul><li>In 9 out of the 14 patients, a temporary pacemaker was required to treat or prevent severe prolonged bradycardia or asystole. Hemolysis and liberation of adenosine from red blood cells during thrombectomy has been thought to be the cause of the bradyarrhythmias. </li></ul><ul><li>Mortality With PRT for PE </li></ul><ul><li>The in-hospital mortality in our series was 21.4%. Since most patients included in our series would not be eligible for any clinical trials of current treatment options, a real comparison of their outcomes to previously published data from clinical trials is not possible. Mortality from PE in this high-risk population is at least in the order of 10-40% and may be as high as 65% in untreated patients [[ 13 ]]. </li></ul>
  3. 3. <ul><li>Hemoptysis With PRT </li></ul><ul><li>Of major concern is the occurrence of hemoptysis, which is associated with a mortality rate 50% [[ 15 ][ 17 ][ 19 ][ 20 ][ 30 ]]. Potential causes of hemoptysis associated with PRT are (1) dissection or perforation of the pulmonary arteries due to injury from guide wire or catheter, (2) vessel wall disruption caused by the thrombectomy device, (3) side effect of anticoagulation or thrombolytics, (4) hemorrhagic conversion of pulmonary infarct, (5) reperfusion injury, and (6) formation of pulmonary arteriovenous fistula. In our series, 1 patient (7.1%) developed self-resolving massive hemoptysis, possibly due to brisk distal reperfusion after successful PRT of a large occlusive thrombus. Perforation of the pulmonary vessels was unlikely since there was no dissection or extravasation of contrast noted by angiography or chest CT performed within an hour after the procedure. Of the 26 patients treated with AngioJet in the published reports (Table III ), 3 patients developed massive hemoptysis, and 2 of them died [[ 17 ][ 19 ][ 20 ]]. Biederer et al. referred to a patient who developed a perforation of the pulmonary vasculature with severe hemoptysis and died following the procedure [[ 20 ]]. They studied the safety of a 6-Fr. Xpeedior AngioJet catheter in a porcine pulmonary arteries ranging from 2 to 10 mm in diameter and concluded that use of AngioJet in vessels <6 mm was associated with a higher risk of vessel wall disruption and hemoptysis. It must be emphasized that the thin walled distal pulmonary vessels may be particularly prone to perforation, and careful attention must be paid. </li></ul><ul><li>Adjunctive Use of Local Thrombolytic Agents </li></ul><ul><li>Local intrapulmonary infusion of thrombolytics has been used after fragmentation of the embolus with various devices [[ 31 ]]. A larger surface area of the clot can be exposed to thrombolytic after clot debulking with those devices. Previous studies have used infusion of a full dose of thrombolytics over several hours [[ 32-34 ]]. In our series, a small amount of r-tPA was locally administered as a bolus in 5 patients after thrombectomy. Self-limiting hematuria occurred in all these patients, but no other serious systemic effects of r-tPA were noted. Certainly, the safety and efficacy of local infusion of small doses of r-tPA following thrombectomy as well as optimal regimen and method of delivery ( power pulse spray vs. direct infusion) need to be addressed. </li></ul><ul><li>CONCLUSION </li></ul><ul><li> </li></ul><ul><li>PRT using the AngioJet system appears to be a promising treatment option for patients with massive proximal PE who are hemodynamically unstable and may not be eligible for thrombolytic therapy or surgical embolectomy. Large randomized clinical trials must be pursued to assess the safety, efficacy, and long-term outcomes of rheolytic thrombectomy for the treatment of massive and submassive PE. </li></ul>
  4. 4. <ul><li>See also AJC 2008;101:252-8 </li></ul><ul><li>24 pts from italy </li></ul><ul><li>Presented cath conf jan 08 </li></ul>