Algorithm of High-Risk Massive Pulmonary Thromboembolism with Extracorporeal Membrane Oxygenation

This study focuses on the use of extracorporeal membrane oxygenation (ECMO) as a treatment strategy for patients with high-risk massive pulmonary embolism (PE). The research examines the role of ECMO in conjunction with surgical pulmonary embolectomy and catheter-based thrombectomy, evaluating its impact on hemodynamic stabilization and survival outcomes. The study analyzed 27 patients treated between 2018 and 2023, providing insights into the timing, efficacy, and challenges associated with ECMO in this critical condition.

Background

Massive PE is a life-threatening condition characterized by severe hemodynamic instability and right ventricular failure. Despite advances in diagnostic and therapeutic approaches, including thrombolysis and catheter-based interventions, many patients remain unresponsive to these treatments or are contraindicated for thrombolysis due to bleeding risks. In such cases, surgical pulmonary embolectomy or ECMO may serve as alternative life-saving interventions. ECMO, particularly veno-arterial (VA) ECMO, offers circulatory and respiratory support by bypassing the failing cardiopulmonary system, allowing stabilization before definitive treatments.

Methods

The study included patients with high-risk massive PE who were treated at a tertiary cardiovascular center. Of the 27 patients, 20 underwent VA-ECMO for preoperative stabilization, while the remaining 7 received intraoperative ECMO support due to challenges in weaning from cardiopulmonary bypass. ECMO configurations included VA-ECMO and veno-arterial-venous (VAV-ECMO) in cases complicated by Harlequin syndrome, where differential oxygenation occurred. Patients were monitored for hemodynamic parameters, biochemical markers, and clinical outcomes, including in-hospital mortality.

Results

Among the 27 patients, ECMO demonstrated significant benefits in stabilizing hemodynamic parameters, improving right ventricular function, and facilitating recovery. Key findings included:

• Survival Rates: The in-hospital mortality rate was 18.5% (5 patients), while the remaining 81.5% survived with improved outcomes.
• Hemodynamic Stabilization: ECMO significantly increased mean arterial pressure (from 55.8 mmHg to 67 mmHg) and reduced central venous pressure (from 15.2 mmHg to 6.5 mmHg).
• Right Ventricular Function: Right ventricular ejection fraction improved from 33% to 37.2%, while the ratio of right to left ventricular diameters decreased significantly.
• Biochemical Improvements: Lactate levels reduced from 5.9 mmol/L to 1.95 mmol/L, indicating enhanced tissue perfusion.
• ECMO Challenges: Complications included Harlequin syndrome in 9 patients, necessitating conversion to VAV-ECMO.

Discussion

The study highlights ECMO’s ability to serve as a bridge to recovery in patients with massive PE who fail conventional therapies. By stabilizing hemodynamics and improving cardiac and pulmonary function, ECMO creates a window for definitive treatments like surgical embolectomy. However, its use is not without challenges, such as procedural complications, Harlequin syndrome, and the need for multidisciplinary decision-making.

Conclusion

ECMO is an effective intervention for high-risk massive PE, particularly when combined with surgical or catheter-based interventions. It offers critical hemodynamic and respiratory support, improving survival outcomes in patients unresponsive to thrombolysis or other standard treatments. Future studies are needed to refine patient selection, optimize timing, and evaluate long-term outcomes to establish ECMO’s definitive role in massive PE management.