Snapshot A 46-year-old graduate man presents to the clinic with sudden-onset dyspnea and pleuritic chest pain. The patient recently had his gallbladder removed and has been recovering at home in bed. The patient is a current 2 pack per day smoker for the past 15 years. On physical exam the pateint is clearly short of breath and tachycardic. An EKG performed demonstrates sinus tachycardia with no other abnormalities. Overview Occlusion of the pulmonary vasculature usually by a thromboembolus 95% originate from DVT in the leg veins, most commonly the proximal deep veins of the lower extremities Patients classically characterized as pregnant/postpartum oral contraceptive users smokers long-distance travellers (i.e. international flights or cross-country car rides) Often lead to pulmonary infarct right-sided heart failure hypoxia Pathophysiology Stasis, hypercoagubility and endothelial dysfuntion lead to aberrant clotting, particularly in deep veins clots in deep veins can break off and travel to pulmonary vasculature Risk factors include Virchow's triad stasis immobility CHF obesity surgery long flights or car rides endothelial damage trauma fracture previous DVT hypercoagulable states pregnancy OCP protein C/S deficiency factor V Leiden severe burns cancer essential thrombocythemia Presentation Symptoms sudden-onset dyspnea pleuritic chest pain low-grade fever cough anxiety hemoptysis (rarely) Physical exam tachypnea tachycardia hypoxia and hypocarbia resulting in respiratory alkalosis erythematous, swollen, warm, lower extremity indicative of suspected DVT positive Homan's sign calf pain on forced dorsiflexion Diagnostic algorithms PERC criteria: if none present, rules out DVT/PE in outpatient setting age > 50 years pulse > 99/minute O2 saturation <95% personal history of VTE trauma/surgery within 4 weeks estrogen intake unilateral leg swelling hemoptysis Diagnosis Best initial tests chest radiograph usually normal may show pleural effusion Hampton's hump, a wedged-shaped infarct Westermark's sign, oligemia in the embolized lung zone EKG not diagnostic most commonly reveals sinus tachycardia right heart strain signs of right heart strain classic triad (unlikely to be seen) S-wave in lead I Q-wave in lead III T-wave inversion in lead III new onset right bundle branch block ABG shows respiratory alkalosis from hyperventilation PO2 < 80 mmHg PCO2 < 40 mmHg Alveolar-Arterial gradient may be elevated Confirmatory tests D-dimer sensitive but not specific in patients at risk for PE/DVT use this test if you simply want to rule out a diagnosis of PE; normal D-dimer = not a PE V/Q scan use if chest radiograph is normal may reveal segmental areas of concern interpreted on the basis of clinical suspicion as follows if normal, rules out PE if indeterminate, then test for DVT if DVT negative, proceed to angiography if high probability, then proceed with treatment pulmonary angiogram diagnostic gold standard more invasive and rarely performed - highest mortality CT angiogram use if chest radiograph is abnormal sensitive for PE in the proximal pulmonary arteries (i.e., saddle PE) less sensitive in distal segmental arteries venous ultrasound of lower extremity can detect clot that might be responsible for emboli serial ultrasounds have high diagnostic specificity can miss many DVT's in pelvic veins Differential Myocardial infarct, acute asthma attack, spontaneous pneumothorax, inhalation of foreign object Treatment Non-operative anticoagulate heparin bolus followed by weight-based continuous infusion or LWMH SQ warfarin for long-term anticoagulation usually given for 6 months unless predisposing factor persists must follow INR with goal = 2-3 thrombolysis only indicated in severe cases massive DVT PE causing RHF and hemodynamic instability contraindicated in patients with recent surgery or bleeding disorder Operative Greenfield IVC filter indicated for patients with documented DVT in lower extremity only if anticoagulation is contraindicated i.e. most cancer patients recent trauma, CPR, or surgery or bleeding disorder or in patients with recurrent pulmonary emboli while anticoagulated Prognosis, Prevention, and Complications Prognosis varies depending on size of PE and timing of diagnosis/intervention evidence of cardiac strain linked with poor outcomes elevated cardiac markers confers increased short term mortality Prevention always prophylax bedridden and post-operative patients SQ heparin, LMWH, intermittent pneumatic compression of lower extremities, and early ambulation (most effective) Complications can lead to shock and death if large PE left untreated High Yield Immobilized patient with shortness of breath and tachycardia Diagnosis best initial tests chest radiography EKG ABG confirmatory tests CT angiogram V/Q scan lower extremity doppler D-dimer testing angiography Treatment heparin and oxygen, long term anticoagulation with warfarin IVC filer if patient has contraindication to anticoagulation thrombolytics if patient is unstable