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Introduction
The use of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for the support of critically ill patients with cardiogenic shock is rapidly increasing. Intracardiac thrombus formation is a well-recognized complication. We present 3 cases of dramatic intracardiac thrombosis after the initiation of VA-ECMO.
Case 1
A 64-year-old man presented to a community hospital 3 days after the onset of chest pain with ECG evidence of anterior ST-elevation–myocardial infarction and clinical findings of cardiogenic shock. Physical examination was notable for a pansystolic murmur suggestive of a ventricular septal defect. Coronary angiography showed an occluded left anterior descending artery. Echocardiography confirmed an ischemic ventricular septal defect. He was taken urgently to the operating room for aortocoronary bypass and ventricular septal defect patch repair. Attempts to wean off cardiopulmonary bypass were unsuccessful, and the patient was placed on central VA-ECMO as a bridge to decision, with the chest left open. Forty-eight hours after the initiation of ECMO, the circuit was converted to a peripheral set-up to facilitate chest closure. Transesophageal echocardiogram performed 24 hours after chest closure showed complete thrombosis of the right ventricle despite full anticoagulation (Figure [A]; Movie I in the Data Supplement). He was taken back to the operating room. On direct visualization, thrombus was present in the right ventricle extending into the main pulmonary artery and its branches. After extensive multidisciplinary review, he was deemed not suitable for definitive management with transplantation or durable mechanical support given the extensive thrombosis in the pulmonary circulation. Philosophy of care changed to intensification of comfort measures, and the patient expired in the intensive care unit.
Echocardiograms of intracardiac thrombus in patients supported with venoarterial extracorporeal membrane oxygenation. Representative echocardiograms of patients in cases 1 through 3. Transesophageal (A) and transthoracic (B and C) echocardiograms depicting hyperechoic material within the ventricular cavity, consistent with acute thrombosis.
Case 2
A 49-year-old woman presented to the emergency room with a 1-week history of nonspecific symptoms and acute onset chest pain. ECG showed anterior ST-elevation–myocardial infarction. The patient was taken urgently to the catheterization laboratory where coronary angiography revealed an acute thrombotic occlusion of the left anterior descending and femoral arteries, suggesting a prothrombotic state. Because of hemodynamic deterioration and the development of cardiogenic shock, the patient was placed on peripheral (femoral) VA-ECMO. Anticoagulation was started. Echocardiography 1 day post-cannulation showed complete thrombosis of the left ventricle (Figure [B]; Movie II in the Data Supplement). In spite of the extracorporeal circuit, the patient developed progressive multiorgan failure and died the next day.
Case 3
A 46-year-old man, lost to follow-up after childhood Tetralogy of Fallot repair, presented with an abrupt history of severe, decompensated heart failure. Investigations demonstrated severe biventricular dysfunction, an 8.2-cm ascending aortic aneurysm and severe regurgitation of the aortic and pulmonary valves. The patient underwent emergency modified tissue Bentall procedure and tissue pulmonic valve replacement. The aneurysm was so large that the left main coronary ostium was distorted with acute angulation and slit-like orifice, and therefore, a left ostioplasty was undertaken. After separation from bypass, a low cardiac output state and ischemic ECG changes prompted coronary angiography which revealed left main ostial stenosis. Salvage left main stent insertion failed to prevent the patient’s deterioration, and an emergent left femoral VA-ECMO was implemented. Six days post-ECMO cannulation, echocardiography showed no appreciable recovery in ventricular function, and conversion to ventricular assist device was therefore entertained. However, before operation, transthoracic echocardiography demonstrated near complete thrombosis of the left ventricle despite routine anticoagulation (Figure [C]; Movie III in the Data Supplement). The clot was evacuated via a ventriculotomy, and Centrimag support was initiated via left ventricular aortic cannulation. The patient eventually had a durable HeartWare left ventricular assist device implanted at a later date. He was discharged home and is recovering well.
Discussion
The application of extracorporeal membrane oxygenation (ECMO) for critical cardiogenic shock is increasing worldwide. In 2015, there were 2167 adult cases reported requiring extracorporeal life support in the Extracorporeal Life Support Organization registry for cardiac indications.1 ECMO may provide support as a bridge to recovery, as a bridge to decision, or as a bridge to advanced heart failure therapies. In observational trials, although patients had improved survival, mortality is significantly higher in patients who required ECMO for >3 days.2
Many complications associated with ECMO use have been reported, including bleeding, cannulation site complications, brain and coronary hypoxia, and thromboembolism. Circulatory support with an ECMO circuit may predispose to the development of intracardiac thrombosis by different mechanisms, all of which may involve ≥1 components of Virchow triad. The prevalence of intracardiac thrombosis while on ECMO support has not been systematically documented in the literature. Its occurrence, however, has been noted in a growing number of case reports as a reflection of the increasing utilization of this technology.3 Active surveillance for the development of spontaneous echo contrast and strategies that minimize its occurrence may decrease the risk of intracardiac thrombus formation and the potential for systemic embolization.
The Extracorporeal Life Support Organization registry has published recommendations on optimal anticoagulation management for patients on ECMO that includes the use of intravenous heparin with titration to achieve an activated clotting time of 180 to 220 s. However, these recommendations are often modified in response to patient-specific clinical scenarios.
Routine cardiac decompression may prevent ventricular thrombus formation in patients at risk of ventricular distention. These include patients with aortic regurgitation, high afterload, and the absence of ejection.4 Although different modalities to achieve decompression have been described, once intracardiac thrombus is present, the optimal treatment for such patients is unknown and may include surgical removal.
Summary
We present 3 dramatic cases of intracardiac thrombosis while on VA-ECMO support. Early recognition, aggressive venting strategies, and anticoagulation are important to possibly prevent this frequently lethal complication.
Disclosures
None.
Footnotes
The Data Supplement is available at http://circheartfailure.ahajournals.org/lookup/suppl/doi10.1161/CIRCHEARTFAILURE.116.003757/-/DC1.
- Received November 29, 2016.
- Accepted January 20, 2017.
- © 2017 American Heart Association, Inc.
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- Ventricular Thrombosis Post-Venoarterial Extracorporeal Membrane Oxygenation
