Pulmonary Embolism and Infarction

Pulmonary Embolism Falls under the spectrum of diagnosis called VTE 600,000 episodes occur yearly causing 200,000 deaths Death is uncommon after proper dx and treatment is initiated Majority of PE’s are from LE’s but only 30% have leg symptoms

Pathophysiology Dislodged thrombi travel through Rt heart and lodge in pulmonary arterial circulation Small emboli vs. large emboli

Risk Factors Age (advanced) Cigarette smoking Extended travel history History of VTE** HTN HRT Immobilization** Recent joint replacement LE bone fx Malignancy** Obesity OCP’s Trauma Pregnancy Surgery w/in past 3 months** Stroke**

Risk Factors, cont. Anticardiolipin syndrome Antithrombin III deficiency Factor V Leiden Lupus Anticoagulant Protein C or S deficiency Prothrombin G20210A mutation (Evaluation for above causes should be limited to pt’s with recurrent or FHx of VTE)

Signs and Symptoms Dyspnea (73%) Tachypnea (70%) Pleuritic Pain (66%) Rales (51%) Cough (37%) Tachycardia (30%) S4 (24%) Hemoptysis (13%)

Diagnosis What do you order first? CXR EKG ABG Chem 7 CBC Ddimer Troponin BNP

EKG’s

CXR

Definitive Imaging Studies Pulmonary Angiography Requires right heart catheterization and 4 injections of iodinated contrast Associated with 5% morbidity and 0.5% mortality rate Reserved when other tests are all inconclusive

Figure 1.Massive pulmonary thromboembolism, seen at pulmonary angiography in a patient with recent resection of colonic cancer, undergoing chemotherapy, who had suddenly collapsed in the ward.

V/Q scans 97% specific when “high probability” 95% predictive value when high clinical probability 14% false positive rate Normal perfusion scan excludes PE Intermediate requires further work-up

Normal perfusion images Normal ventilation on the left with abnormal perfusion scan on the right

Findings: A large mismatch defect is present in the anterior segment of the right upper lobe. Additionally, there are unmatched perfusion defects in the apicoposterior segment of the left upper lobe and the anteromedial basilar segment of the left lower lobe.

Helical CT scan CTPA (CT pulmonary angiography) is considered first line modality by some clinicians Specificity (87-97%) Sensitivity (53-60%) Added benefit of suggesting alternative dx Neg result is insufficient to exclude PE in mod to high risk patients (need to perform NIV of LE’s)

CT Pulmonary Angiography CT Pulmonary Angiography. Arrow points to thrombus in right upper lobe pulmonary artery.

Multiple lower lobe segmental pulmonary emboli Thrombus at the bifurcation of the right interlobar pulmonary artery Thrombus within the origin of the right interlobar pulmonary artery

Other Studies Magnetic Resonance pulm angiography LE evaluation minimal value in dx LE evaluation useful when clinical suspicion is high and V/Q scan is unequivocal ultrasound is 90% sensitive for DVT

Other Studies, cont. Echocardiogram used for risk stratification when pts are hemodynamically unstable Common findings include RV dysfunction, RV dilation, and patent foramen ovale McConnell Sign: normal contraction of RV apex despite moderate to severe RV free wall hypokinesis 94% specific for PE

Treatment Heparin Coumadin LMWH IVC filters

IVC or Greenfield filters

Heparin vs. LMWH LMWH developed in the 90’s 1-2x daily, SQ no monitoring needed provides immediate anticoagulation can be used in outpatients 2004 American College of Chest Physicians: LMWH has therapeutic equivalence to unfractionated heparin in proximal DVT’s and VTE

Coumadin INR goal of 2-3 Duration is controversial 2004 ACCP consensus statement provides the guidelines for long-term treatment

ACCP guidelines 1. Pts with first epidode caused by reversible risk factor should have 3 months of warfarin treatment. 2. Pts with first episode of idiopathic PE should have 6-12 months of warfarin and be considered for indefinite therapy. 3. PE and cancer should have LMWH for 3-6 months and then warfarin indefinitely.

ACCP guidelines, cont. 4. Pts with first PE with antiphospholipid Ab’s or 2+ thrombophilic conditions should be treated for 12 months or indefinitely. 5. Two or more episodes of PE should be considered for indefinite treatment. See www.chestjournal.org for full consensus guidelines.

Treatment, cont. Thrombotic therapy Pulmonary Embolectomy reserved for hemodynamically unstable patients many contraindications Pulmonary Embolectomy unstable pts with contraindications to thrombolysis severe RV dysfunction catheter based procedure