Volume 26, Issue 2 , Pages e13-e14, April 2012
Intracardiac Clots Masked by Extracorporeal Membrane Oxygenation Venous Cannula
Article Outline
To the Editor:
The impact of coated circuits on thrombotic complications is still controversial. As reported by Sidebotham et al,1 thrombus is not unusual in patients supported with a heparin-coated extracorporeal membrane oxygenation (ECMO) circuit without systemic heparinization. In the clinical setting of mechanical circulatory support, transesophageal echocardiography plays an essential role in detecting the potential periprocedural complications, such as cannulation-related injuries, thrombosis, and infections.2 Systemic heparinization (unfractionated heparin) during ECMO support may be challenging because of the potential bleeding. In contrast, low doses of heparin may decrease the risk of bleeding by providing a more biocompatible surface in the circuit and minimizing the surface-induced complement activation and platelet dysfunction. However, thrombus formation may occur in the ECMO circuit as a potential hazard.3, 4 Therefore, a systematic search for intracardiac thrombi is strongly recommended. The authors report two patients with venoarterial ECMO support in which intracardiac clots were trapped between the venous cannula and the interatrial septum.
A 71-year-old man who had undergone cardiac surgery (mitral valve repair, coronary artery bypass, and radiofrequency ablation of atrial fibrillation) developed severe biventricular dysfunction requiring inotropic support and an intra-aortic balloon pump. As the hemodynamic impairment became refractory (intra-aortic balloon pump score >2), a venoarterial ECMO circuit was positioned with cannulation of the left femoral artery and right femoral vein with 17Fr and 23Fr multistage Bioline-coated cannulae (Maquet Cardiopulmonary AG, Hechingen, Germany), respectively.
The second patient was a 75-year-old man admitted to an intensive care unit for mediastinitis with life-threatening hemodynamic impairment after left ventricular aneurysmectomy (Dor procedure). The treatment included inotropic support, an intra-aortic balloon pump, and a venoarterial ECMO circuit using the same cannulae and cannulation strategy.
In these two cases, anticoagulation with unfractionated heparin was targeted to a 40- to 45-second partial thromboplastin time due to recent surgery. Transesophageal echocardiography, performed for daily monitoring, displayed intracardiac blood stasis and a peculiar interatrial septum bulging into the left atrium by the ECMO venous cannula (Fig 1A). Once the cannula had been pulled back (Fig 1B), a large and mobile thrombus was found attached to the atrial septum (Fig 1C, D), near the tip of the cannula (Fig 1B), and floating into the right atrium. Subsequent and adequate anticoagulation therapy led to complete thrombus dissolution.
Fig. 1.
Transesophageal echocardiograms showing intracardiac clots related to the extracorporeal membrane oxygenation venous cannula. (A) The interatrial septum bulges (arrow) into the left atrium by the extracorporeal membrane oxygenation venous cannula. (B) Pullback of the extracorporeal membrane oxygenation cannula discloses the thrombus (arrow) entrapped between the septum and the tip of the cannula. (C, D) Large thrombus attached to the interatrial septum (arrow) and floating into the right atrium. LA, left atrium; RA, right atrium.
References
- Extracorporeal membrane oxygenation for treating severe cardiac and respiratory failure in adults: Part 2-technical considerations . J Cardiothorac Vasc Anesth . 2010;24:164–172
- Outcomes and long-term quality-of-life of patients supported by extracorporeal membrane oxygenation for refractory cardiogenic shock . Crit Care Med . 2008;36:1404–1411
- Review of ECMO (extra corporeal membrane oxygenation) support in critically ill adult patients . Heart Lung Circ . 2008;17(suppl 4):S41–S47
- Complications of extracorporeal life support systems using heparin-bound surfaces (The risk of intracardiac clot formation) . J Thorac Cardiovasc Surg . 1995;110:843–851
PII: S1053-0770(11)00710-5
doi:10.1053/j.jvca.2011.10.007
© 2012 Elsevier Inc. All rights reserved.
Volume 26, Issue 2 , Pages e13-e14, April 2012
