What is the next step in managing a patient with suspected pulmonary embolism (PE) and a moderate-to-high probability Wells score?

Management of Suspected PE with Moderate-to-High Probability Wells Score

In this patient with a Wells score of 5.5 (moderate-to-high probability), you should immediately initiate therapeutic anticoagulation with weight-adjusted intravenous heparin and proceed directly to CT pulmonary angiography (CTPA) without obtaining a D-dimer test. 1

Immediate Anticoagulation

• Start therapeutic anticoagulation immediately while arranging imaging, as the American College of Physicians and British Thoracic Society both emphasize that heparin should be initiated based on high or intermediate clinical suspicion before diagnostic confirmation 1, 2
• Administer an initial IV bolus of 80 units/kg followed by continuous infusion of 18 units/kg/hour (or alternatively, 5,000 units bolus followed by 1,300 units/hour for standard dosing) 1, 3
• Target aPTT of 1.5-2.5 times control (45-75 seconds), checking levels 4-6 hours after the initial bolus 1, 3

Skip D-Dimer Testing

• Do not obtain a D-dimer measurement in patients with high pretest probability of PE 1
• The American College of Physicians explicitly states that D-dimer testing should not be performed when clinical probability is high, as it will not change management and may cause unnecessary delays 1
• D-dimer is only useful for ruling out PE in low or intermediate probability patients, not for confirming it in high-risk patients 1

Proceed Directly to CTPA

• CTPA is now the recommended initial lung imaging modality for non-massive PE and should be obtained urgently in patients with high clinical probability 1, 2, 4
• The British Thoracic Society guidelines state that CTPA should be performed in patients with high pretest probability, with ventilation-perfusion scans reserved only for patients with contraindications to CTPA or when CTPA is unavailable 1
• A good quality negative CTPA reliably excludes PE and allows discontinuation of anticoagulation 1

Clinical Context for This Patient

This 55-year-old woman has multiple features supporting moderate-to-high PE probability:

• Recent major surgery (abdominal surgery 2 weeks ago) is one of the strongest risk factors for PE 1
• Obesity is an additional risk factor 1
• Classic presentation: acute onset pleuritic chest pain, dyspnea, tachycardia (HR 112), tachypnea (RR 22), and hypoxemia (O₂ sat 93%) 1
• Wells score of 5.5 places her in the moderate-to-high probability range where imaging is mandatory 1

Important Caveats

• Do not delay anticoagulation while waiting for imaging - the British Thoracic Society emphasizes that heparin should be started immediately in patients with intermediate or high clinical probability 1, 2
• If CTPA is negative but clinical suspicion remains very high, consider additional imaging such as leg ultrasound for DVT or conventional pulmonary angiography, or seek specialist advice 1
• Monitor for heparin-induced thrombocytopenia by checking platelet counts periodically during heparin therapy 4, 3
• The absence of leg swelling does not exclude PE, as many patients with PE do not have clinically evident DVT 1