Neonatal extracorporeal membrane oxygenation (ECMO) is a critical intervention for newborns with severe respiratory or cardiac failure, often used in cases like congenital diaphragmatic hernia (CDH). However, ECMO is associated with significant risks, including thrombotic complications that can lead to devastating outcomes. This case study examines the rare but lethal occurrence of myocardial infarction (MI) in a neonate due to a thrombus formation during ECMO support.
Case Overview
A term neonate was diagnosed prenatally with a moderate-risk left-sided CDH. Delivered at 39 weeks via spontaneous vaginal birth, the baby required immediate respiratory support. Echocardiography at birth revealed severe pulmonary hypertension and biventricular dysfunction. The baby was treated with inhaled nitric oxide, milrinone, and epinephrine. On the sixth postnatal day, surgical repair of the CDH was performed, but the infant experienced worsening pulmonary hypertension and respiratory distress, necessitating ECMO initiation on day 25.
During ECMO support, clot burden in the circuit increased despite aggressive anticoagulation adjustments. On ECMO day 9, the baby suffered acute hypotension that did not respond to fluid resuscitation or vasopressors. An urgent echocardiogram revealed a large thrombus extending from the arterial cannula into the left main coronary artery (LMCA), obstructing coronary blood flow and leading to profound left ventricular dysfunction. The neonate’s electrocardiogram showed ST-segment elevation, indicative of myocardial infarction.
Given the severe prognosis, a multidisciplinary team—including neonatologists, pediatric cardiologists, and surgeon’s determined that further interventions were futile. After discussions with the family, care was compassionately withdrawn.
Discussion
Intracardiac thrombotic events in neonatal ECMO are underreported, with most ECMO-related thromboses being circuit-based. The Extracorporeal Life Support Organization (ELSO) database suggests that neonatal patient-related thrombotic complications are rare, with most reported cases involving intracranial or limb ischemia rather than intracardiac thrombosis.
Several factors may have contributed to thrombus formation in this case:
- Neonatal Hemostasis Differences: The delicate balance between procoagulant and anticoagulant factors in neonates makes them more prone to clotting, even under anticoagulation therapy.
- Aortic Arch Hypoplasia: CDH patients often have vascular anomalies, including small aortic arches, which may predispose them to blood stasis and thrombosis.
- Cannula Placement: The arterial cannula was positioned deeply in the aorta, possibly leading to disturbed flow dynamics that facilitated clot formation.
- Persistent Pulmonary Hypertension: Severe pulmonary hypertension may have increased cardiac strain, further compromising circulation and promoting thrombosis.
The detection of coronary thrombosis was particularly challenging. Traditional color Doppler echocardiography can be difficult in neonates due to low coronary flow velocities, necessitating specialized techniques such as adjusting the Nyquist limit to enhance visualization. In this case, targeted neonatal echocardiography (TNE) played a crucial role in identifying the thrombus and its impact on cardiac function.
Management Challenges and Future Directions
Managing ECMO-related thrombosis in neonates remains complex, with options including:
- Surgical Thrombectomy: Rarely performed in neonates due to high risk.
- Interventional Catheterization: Some cases benefit from direct thrombus removal or stenting.
- Thrombolysis: Recombinant tissue plasminogen activator (rtPA) has shown promise but carries bleeding risks.
- Ultrasound-Enhancing Agents: Emerging techniques that may improve clot visualization and microvascular perfusion.
Despite these potential interventions, the rapid deterioration in this case precluded aggressive treatment. Future research should focus on refining anticoagulation protocols, improving early thrombus detection via echocardiography, and exploring alternative ECMO configurations to minimize clot risk.
Conclusion
Neonatal myocardial infarction due to ECMO-associated intracardiac thrombosis is a rare but catastrophic event. This case underscores the importance of vigilant monitoring, optimized anticoagulation management, and advanced echocardiographic techniques for early clot detection. Further studies are needed to enhance patient outcomes by refining ECMO protocols and improving thrombus management strategies.
Study Ranking: 3 (Medium Quality) While a case report, this study provides a detailed clinical case with well-supported discussion and references, contributing valuable insights into a rare but critical neonatal complication.
