Acute Pulmonary Embolism Overview lecture.ppt
- 2. Why care? PE is the most common preventable cause of death in hospitalized patients ~600,000 deaths/year 80% of pulmonary emboli occur without prior warning signs or symptoms 2/3 of deaths due to pulmonary emboli occur within 30 minutes of embolization Death due to massive PE is often immediate Diagnosis can be difficult Early treatment is highly effective
- 3. Pathology At least 90% of pulmonary emboli originate from major leg veins.
- 6. Natural History of VTE 40-50% of patients with DVT develop PE, often “silent” PE presents 3-7 days after DVT Fatal within 1 hour after onset of respiratory symptoms in 10% Shock/persistent hypotension in 5-10% (up to 50% of patients with RV dysfunction) Most fatalities occur in untreated patients Perfusion defects completely resolve in 75% of all patients (who survive)
- 7. Diagnosis: Clinical Presentation Dyspnea, tachypnea, or pleuritic chest pain most common Pleuritic pain = distal emboli pulmonary infarction and pleural irritation Isolated dyspnea of rapid onset= central PE with hemodynamic sequlea Retrosternal angina like symptoms = RV ischemia Syncope=rare presentation, but indicates severely reduced hemodynamic reserve symptoms can develop over weeks In patients with pre-existing CHF or COPD, worsening dyspnea may indicate PE
- 9. Diagnosis: Chest X-Ray Usually abnormal, but non-specific Study of 2,322 patients with PE: Cardiac enlargement (27%) Normal (24%) Pleural effusion (23%) Elevated hemidiaphragm (20%) Pulmonary artery enlargement (19%) Atelectasis (18%) Parenchymal pulmonary infiltrates (17%) Chest Radiographs in Acute Pulmonary Embolism: Results From the International Cooperative Pulmonary Embolism Registry. Chest July 2000 118:3338; 10.1378/chest.118.1.33
- 10. Diagnosis: ECG Usually non-specific ST/T waves changes and tachycardia RV strain patterns suggest severe PE
- 11. Diagnosis:Other tests Most patients with PE have a normal pulse oximetry
- 12. Clinical Diagnosis of PE In summary, clinical signs, symptoms and routine tests do not allow for the exclusion or confirmation of acute PE but may increase the index of its suspicion Consider PE in cases of unexplained tachycardia or syncope
- 13. Diagnosis-Probability Assessment Implicit clinical judgement is fairly accurate: “Do you think this patient has a PE?” Validated prediction rules standardize clinical judgement Wells Geneva
- 16. Diagnosis D-Dimer Fibrin degradation product Non specific (~40%): cancer, sepsis, inflammation increase d-dimer levels
- 17. Spiral CT • Direct visualization of emboli. • Both parenchymal and mediastinal structures can be evaluated. • Offers differential diagnosis in 2/3 of cases with a negative scan. BUT… •Dye load and large radiation dose •Optimally used when incorporated into a validated diagnostic decision tree
- 20. 3 month VTE rate 0.5% (all non fatal) 1.3% This algorithm allowed for a management decision in 98% of patients presenting with symptoms suggestive of PE
- 21. Diagnosis- Summary History and physical examination Then 1,2,3 approach: 1. Clinical decision score 2. D-Dimer test 3. Chest CT 3’. (V/Q scan remains a valid option for patients with contraindication to CT)
- 22. Clinical Presentation After disembarking from a 10 hour airline flight, a 69 year old man w/o past medical hx presents to the ER with acute dyspnea. BP is 120/80 (baseline) and pulse is 120 BPM. Wells score = 5 (intermediate), D- Dimer is positive. Spiral CT shows bilateral pulmonary emboli in >50% of arterial tree.
- 23. Poor Prognostic Signs Hypotension (not caused by arrhythmia, sepsis, or hypovolemia) SBP <90 mm Hg = 53% 90-day all cause mortality SBP drop of 40 mm Hg for at least 15 minutes = 15% in–hospital mortality Syncope= bad Shock= really bad
- 24. Transverse contrast-enhanced CT scan shows maximum minor axis measurements of the right ventricle (A) and left ventricle (B). van der Meer R W et al. Radiology 2005;235:798-803 ©2005 by Radiological Society of North America
- 25. Echocardiograms before and after Thrombolysis Echocardiography-RV Dilation
- 26. Treatment Pulseless patient with suspected PE: Start ACLS and consider administration of thrombolytics Stabilize the patient and provide supportive care Oxygen supplementation in patients with SpO2 < 90% For patients with respiratory failure: airway management and/or mechanical ventilation (IV fluids, gentle bolus normal saline ≤ 500 mL). Avoid volume overload, which may be harmful in cases of right ventricular strain Analgesics: for patients with pain, Morphine. Avoid NSAIDs if patient receiving anticoagulation or thrombolytics Assess bleeding risk
- 27. Initiate therapy based on risk stratification and bleeding risk. Massive PE: thrombolytic therapy or thrombectomy. Submassive and nonmassive PE: anticoagulation or IVC filter
- 28. Thrombolytic therapy Fibrinolytic therapy, Thrombolysis The pharmacologic breakdown of blood clots formed in vessels. Indications include STEMI, stroke, massive pulmonary embolism, severe deep vein thrombosis, and acute limb ischemia. Agents used include streptokinase and alteplase.
- 29. Alteplase Tissue plasminogen activator Abbreviation: tPA, PLAT, rtPA A serine protease found on endothelial cells of the blood vessels. Catalyzes the conversion of plasminogen to plasmin, which is the main enzyme responsible for clot breakdown.
- 30. Approved thrombolytic regimens for pulmonary embolism Streptokinase 250 000 IU as a loading dose over 30 min, followed by 100 000 IU/h over 12– 24 h Accelerated regimen: 1.5 million IU over 2 h Urokinase 4400 IU/kg as a loading dose over 10 min, followed by 4400 IU/kg/h over 12–24 h Accelerated regimen: 3 million IU over 2 h rtPA (Alteplase)100 mg over 2 h or 0.6 mg/kg over 15 min (maximum dose 50 mg)
- 31. Catheter Embolectomy & Fragmentation An alternative in high-risk PE patients when thrombolysis is absolutely contraindicated or has failed Kucher N Chest 2007;132:657-663
- 32. Bottom line The decision to use thrombolytic therapy in the intermediate risk PE group should be made on a case-by-case basis after carefully weighing the strength of the indication, the potential benefits, the contraindications, and potential adverse effects.
- 33. IVC Filters •May provide lifelong protection against PE •Unclear effect on overall survival • Complications: •DVT (20%) •Post thrombotic syndrome (40%) •IVC thrombosis (30%) •Risk/benefit ratio difficult to determine since no randomized control evidence •Use when there are absolute contraindications to anticoagulation and a high risk of Venous thromboembolism recurrence •Consider in pregnant women with extensive thrombosis •Optimal duration of retrievable filters is unclear
- 34. The key is prevention DVT prophylaxis in at-risk patients is quite effective