Postoperative Pulmonary Embolism: Recognizing Symptoms and Diagnostic Approaches

After surgery, patients who suddenly develop unexplained shortness of breath, rapid breathing, chest pain, coughing up blood, or even fainting should be evaluated immediately for possible pulmonary embolism (PE). These symptoms can signal a life-threatening blockage in the pulmonary arteries, typically caused by a blood clot that has traveled from the legs or pelvis. Early recognition is critical, as delayed diagnosis significantly increases the risk of complications and mortality.

Key Clinical Signs of Postoperative PE

Symptoms of pulmonary embolism can vary widely but often include acute dyspnea, sharp pleuritic chest pain that worsens with breathing, hemoptysis (coughing up blood), tachycardia, and lightheadedness. In severe cases, patients may experience syncope (fainting), which is associated with large or central clots causing significant obstruction of blood flow to the lungs. Clinicians must maintain a high index of suspicion, especially in patients with known risk factors such as prolonged immobility, recent major surgery, or a history of deep vein thrombosis (DVT).

Diagnostic Imaging: From CTA to Gold-Standard Angiography

CT pulmonary angiography (CTPA) is the most widely used imaging modality for diagnosing pulmonary embolism due to its non-invasive nature, high accuracy, and rapid turnaround time. It allows clinicians to visualize the location, size, and extent of the clot within the pulmonary arteries. While traditional pulmonary angiography remains the gold standard for PE diagnosis, it is invasive and rarely used outside of specialized centers or complex cases.

In addition to confirming the presence of a clot, CTPA also helps assess right ventricular strain—such as dilation or hypokinesis—which is an important prognostic indicator. Follow-up CTPA scans can further be used to monitor treatment response, particularly in patients receiving anticoagulation or thrombolytic therapy.

Supportive Laboratory and Functional Tests

Besides imaging, several ancillary tests play a crucial role in the diagnostic workup. Arterial blood gas (ABG) analysis often reveals hypoxemia (low oxygen levels) and hypocapnia (reduced carbon dioxide), reflecting impaired gas exchange due to ventilation-perfusion mismatch.

Electrocardiogram (ECG) findings may show nonspecific changes such as sinus tachycardia, but some patients exhibit the classic S1Q3T3 pattern—a deep S wave in lead I, a Q wave in lead III, and an inverted T wave in lead III—suggesting acute right heart strain.

Echocardiography and Biomarkers in Risk Stratification

Transthoracic echocardiography is invaluable in assessing right heart function. Signs like pulmonary hypertension, right ventricular enlargement, or reduced contractility indicate a higher-risk PE that may require more aggressive management.

Laboratory markers such as elevated D-dimer levels are sensitive—though not specific—for PE, especially useful in ruling out the condition when negative in low-risk patients. Additionally, increased levels of cardiac biomarkers like troponin or BNP suggest myocardial injury or stress, helping to stratify patients into intermediate- or high-risk categories for adverse outcomes.

Combining clinical assessment with imaging, ECG, echocardiography, and biomarker data enables a comprehensive approach to diagnosing and risk-stratifying postoperative pulmonary embolism, ultimately guiding timely and effective treatment decisions.