- The D-dimer test is a marker of blood clotting activity and is not diagnostic of VTE
- When used appropriately the D-dimer test helps “rule out” VTE if the test is negative and the chance of the patient having a VTE is relatively low
ECG findings among patients with acute PE: tachycardia (38%), T-wave inversion in lead V1 (38%), and ST elevation in aVR (36%). significant EKG findings which predicted mortality were:
- Heart rate > 100 beats/min,
- complete RBBB,
- inverted T waves in V1–V4,
- ST elevation in aVR,
- atrial ﬁbrillation
The recommendations, based on a literature review and the best available evidence, include:
- Use validated prediction rules (e.g., Wells or Geneva tools) to estimate a patient’s pretest probability of acute PE.
- For patients with a low pretest probability who also meet all Pulmonary Embolism Rule-Out Criteria (PERC), neither D-dimer testing nor imaging should be performed. The PERC comprise eight variables (see link below).
- For patients with an intermediate pretest probability or those who do not meet all PERC, perform high-sensitivity D-dimer testing; imaging should not be done initially.
- For those over age 50, use age-adjusted D-dimer thresholds (instead of the usual 500 ng/mL) to decide whether to proceed to imaging; patients with a low-age-adjusted level should not undergo imaging.
- For patients with a high pretest probability of PE, forego D-dimer testing and go straight to computed tomographic pulmonary angiography. If CTPA is contraindicated or unavailable, ventilation-perfusion lung scanning may be used.