From the Guidelines
The initial management for a patient presenting with shortness of breath, tachycardia, and an elevated D-dimer should focus on stabilization while evaluating for pulmonary embolism (PE) with immediate imaging, preferably a CT pulmonary angiogram (CTPA), as recommended by the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline 1. The clinical presentation of shortness of breath, tachycardia, and an elevated D-dimer raises significant concern for PE, which requires prompt diagnosis and treatment to prevent potentially fatal complications.
- Start with supplemental oxygen to maintain oxygen saturation above 94%, establish IV access, and perform continuous cardiac monitoring.
- Obtain baseline labs including complete blood count, comprehensive metabolic panel, troponin, BNP, and coagulation studies.
- Assess hemodynamic stability; if the patient shows signs of shock (hypotension, altered mental status), prepare for possible thrombolytic therapy with alteplase (100 mg IV over 2 hours) or consider catheter-directed interventions. The use of validated criteria for diagnosing PE is recommended, and initiation of anticoagulation is recommended without delay in patients with high or intermediate clinical probability of PE while diagnostic workup is in progress, as stated in the 2019 ESC guidelines for the diagnosis and management of acute pulmonary embolism 1.
- While awaiting imaging results, if PE is strongly suspected and there are no contraindications, administer therapeutic anticoagulation with either low molecular weight heparin (such as enoxaparin 1 mg/kg subcutaneously twice daily) or unfractionated heparin (80 units/kg IV bolus followed by 18 units/kg/hour infusion). The elevated D-dimer reflects increased fibrin degradation products, suggesting active thrombosis, though it's not specific to PE alone, and plasma D-dimer measurement, preferably using a highly sensitive assay, is recommended in outpatients/emergency department patients with low or intermediate clinical probability, or those that are PE-unlikely, to reduce the need for unnecessary imaging and irradiation 1.
From the Research
Diagnostic Approach for Shortness of Breath, Tachycardia, and Elevated D-dimer
- The initial management for a patient presenting with shortness of breath, tachycardia, and an elevated D-dimer involves assessing the clinical probability of pulmonary embolism (PE) 2.
- A clinical decision rule can determine the pre-test probability of PE, and if PE is "unlikely", a D-dimer test can be performed 3.
- If the D-dimer result is normal, PE can be excluded, but if D-dimer levels are increased, chest imaging is recommended 2, 3.
- Imaging with computed tomography pulmonary angiogram (CTPA) is accurate and preferred for diagnosing PE, but may detect asymptomatic PE of uncertain clinical significance 4, 3.
- Ventilation-perfusion (VQ) scan is associated with lower radiation exposure than CTPA and may be preferred in younger patients and pregnancy 3, 5.
Diagnostic Testing
- D-dimer testing is useful in patients with low or intermediate clinical probability of PE, and a level of less than 500 ng/mL is associated with a posttest probability of PE less than 1.85% 2.
- Chest imaging, such as CTPA or VQ scan, is necessary for patients with high probability of PE or those with elevated D-dimer levels 2, 4, 3.
- Magnetic resonance angiography can also aid in the detection and pre-procedural planning of endovascular therapy in patients who are not candidates for CTPA 5.
Treatment
- Direct oral anticoagulants, such as apixaban, edoxaban, rivaroxaban, or dabigatran, are the preferred anticoagulant for most patients with PE due to their lower risk of bleeding and practical advantages 2, 3.
- Systemic thrombolysis is recommended for patients with PE and systolic blood pressure lower than 90 mm Hg, and is associated with a 1.6% absolute reduction of mortality 2.