Can TACE Cause Pulmonary Embolism?
Yes, TACE can cause pulmonary embolism, specifically pulmonary oil (lipiodol) embolism, which is a recognized and potentially life-threatening complication of the procedure. 1
Mechanism of Pulmonary Embolism in TACE
The primary mechanism involves migration of lipiodol (ethiodized oil) to the pulmonary vasculature through arteriovenous (AV) shunts within hypervascular hepatocellular carcinomas. 2 When lipiodol is infused during conventional TACE (cTACE), it can pass through hepatic sinusoids and veins, ultimately becoming impacted in peripheral pulmonary arteries. 1 This is distinct from thrombotic pulmonary embolism and represents a form of non-thrombotic pulmonary embolism caused by foreign material. 1
Incidence and Clinical Presentation
- Symptomatic pulmonary lipiodol embolism occurs in approximately 2.3% of patients undergoing TACE procedures. 3
- Symptoms typically develop within 12-48 hours after TACE, with the most severe respiratory manifestations presenting between 2-5 days post-procedure. 3
- Clinical presentation includes dyspnea, tachycardia, chest pain, cough, and in severe cases can progress to acute respiratory distress syndrome (ARDS). 2, 4
- Mortality can occur, with fatal cases documented in the literature. 4
Risk Factors for Pulmonary Oil Embolism
The single most important modifiable risk factor is excessive lipiodol volume. 1, 5
Established Risk Factors:
- Lipiodol dose >14.5-15 mL per session is the strongest independent predictor (odds ratio 1.133, sensitivity 80%, specificity 66.3%). 5, 1
- Large hypervascular tumors (mean size 8.55-13.6 cm) with arteriovenous shunts. 3, 5, 2
- Hepatic vein invasion by tumor, creating direct pathways to systemic circulation. 6
- Higher doxorubicin doses (>50 mg per session). 5
- Advanced liver cirrhosis (higher Child-Pugh class). 5
- Lower serum albumin levels (<3.25 g/dL). 5
- Embolization via the right inferior phrenic artery. 2
Prevention Strategies
Limit lipiodol to a maximum of 15 mL per session, ideally ≤10-14.5 mL. 1, 5
Pre-procedural Assessment:
- Carefully evaluate for arteriovenous shunts on pre-treatment angiography. 1
- Check for hepatic vein invasion on imaging, which increases risk of systemic embolization. 6
- Perform selective angiography to identify tumor-feeding vessels and avoid non-target embolization. 1
Intra-procedural Precautions:
- Use cone-beam CT (CBCT) to precisely identify vascular anatomy and detect AV shunts. 1
- Perform superselective TACE with 1.5-2.0 F microcatheters when technically feasible. 1
- Monitor for real-time lipiodol passage through hepatic veins during fluoroscopy. 1
- Consider staged procedures for large tumors rather than single high-volume lipiodol infusions. 1
Diagnostic Features
Chest CT showing high-density lipiodol deposition in the lung parenchyma is pathognomonic. 3
- Radiographic findings include diffuse or focal radiopaque material in pulmonary vessels and parenchyma. 3
- Imaging abnormalities typically normalize between 12-35 days after TACE in survivors. 3
- The absence of known risk factors does not guarantee against serious complications. 2
Management Approach
When pulmonary oil embolism is suspected:
- Initiate immediate supportive care with supplemental oxygen. 6
- Provide mechanical ventilation if respiratory failure develops. 4
- Administer corticosteroids for inflammatory response (though evidence is limited). 6
- Monitor closely in intensive care setting for progression to ARDS. 4
- Recognize that outcomes vary from complete recovery to fatal ARDS despite aggressive treatment. 4, 6
Critical Clinical Pitfall
The most common error is using excessive lipiodol volumes (≥20 mL), which "potentially causes pulmonary embolization and dyspnea." 1 The Korean Liver Cancer Association expert consensus specifically limits maximum lipiodol dose to 15 mL per session to prevent this complication. 1 Even in the absence of visible AV shunts, microscopic shunting can occur in hypervascular tumors, making volume restriction essential for all patients. 2