J Extra Corpor Technol 2025 , 57 , 24 – 31 Ó The Author ( s ), published by EDP Sciences , 2025 https :// doi . org / 10.1051 / ject / 2024031
Available online at : ject . edpsciences . org
REVIEW ARTICLE
Variability in triggers for mechanical left ventricular unloading in VA-ECMO : A literature search
Anthony Calhoun ( MS , CPP , LP ) 1 ,* , Min-Ho Lee ( Ph . D ., CCP ) 2 , Dominic V . Pisano ( MD ) 3 , Alexandros Karavas ( MD ) 4 , and Jamel Ortoleva ( MD , FASE ) 3
1 Department of Perfusion , Boston Medical Center , 732 Harrison Ave 3rd Floor , Boston , MA 02118 , USA 2 Perfusion Services , Children ’ s Hospital of Philadelphia , 3401 Civic Center Blvd , Philadelphia , PA 19104 , USA 3 Department of Anesthesiology , Boston Medical Center , 750 Albany Street , Floor 2R , Power Plant Building , Boston , MA 02118 , USA 4 Division of Cardiac Surgery , Boston Medical Center , 750 Albany Street , Boston , MA 02118 , USA
Received 10 June 2024 , Accepted 21 October 2024
Abstract – Background : Venoarterial Extracorporeal Membrane Oxygenation ( VA-ECMO ) is a means of supporting the lungs or the heart and lungs in patients with hemodynamic compromise that is refractory to conventional measures . VA-ECMO is most commonly deployed in a percutaneous fashion with femoral arterial and venous access . While VA-ECMO , particularly in a femoral-femoral configuration , provides both hemodynamic and ventilatory support , it also causes increased afterload on the left ventricle ( LV ) which in turn may result in LV distension ( LVD ). LV thrombus formation , ventricular arrhythmias , pulmonary edema , and pulmonary hemorrhage are clinical manifestations of LVD . LV unloading is a means of preventing LVD and its sequelae . If less invasive methods fail to achieve adequate LV unloading , invasive mechanical methods are pursued such as intra-aortic balloon pump counter-pulsation , atrial septostomy , surgical venting , left atrial cannulation , and percutaneous transvalvular micro-axial pump placement . Methods : We sought to review indicators of LVD , thresholds , and options for mechanical venting strategies . A Pubmed search was performed to identify current literature about LV unloading for VA ECMO . This was categorized and summarized to determine commonly reported thresholds for mechanical LV unloading . Results : Multiple physiologic and radiographic indicators were reported without uniformity . Common indicators included increased pulmonary artery catheter pressures , decreased Aortic Line Pulse Pressure , as well as multiple Echocardiographic , and radiographic indicators . Conclusion : Although there has been significant interest in the topic , there is currently limited uniformity in thresholds for when to initiate and escalate mechanical LV unloading . While the method of LV unloading is an active area of investigation , the threshold for which to initiate invasive venting strategies is largely unexplored .
Key words : Extracorporeal membrane oxygenation ( ECMO ), Left ventricular unloading , Left ventricular distension , Mechanical unloading , Literature review , Venoarterial ECMO ( V-A ECMO ).
Introduction
Venoarterial Extracorporeal Membrane Oxygenation ( VA-ECMO ) increases left ventricle ( LV ) afterload and in certain instances reduces aortic valve ( AV ) opening resulting in LV distension ( LVD ) [ 1 – 3 ]. Unloading the LV during VA-ECMO is an important maneuver to treat and avoid complications such as pulmonary edema , pulmonary hemorrhage ( if due to elevated left atrial pressure ), ventricular arrhythmias , LV thrombus burden , and aortic root thrombosis caused by LVD and lack of AV opening [ 2 , 4 ]. LV unloading can be accomplished either by non-invasive maneuvers such as afterload reduction ( for example , using vasodilators , decreasing VA-ECMO flow , increasing positive end-expiratory pressure ),
* Corresponding author : Tony @ bostonperfusion . com inotropic support , and diuresis , or by invasive mechanical methods [ 2 , 5 ]. Invasive mechanical methods are effective but come with an increased risk of access site complications , hemolysis , and other drawbacks [ 6 , 7 ]. A growing body of randomized and retrospective literature exists regarding the effects of LV unloading on outcomes [ 7 – 12 ]. Despite ongoing research on the use of unloading strategies , the optimal strategy of monitoring , triggers , and methods of mechanical unloading in VA-ECMO have not been established . At the current time , there is no standard of care escalation pathway for mechanical unloading in the VA-ECMO population , though guidelines do exist based on clinical , hemodynamic , and radiographic evidence of pulmonary congestion [ 5 ]. Unfortunately , these guidelines are not supported by randomized evidence and the expanding options for LV mechanical unloading significantly complicate decision-making and add inter-institutional
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