Table 1.

LV unloading during veno-arterial extracorporeal membrane oxygenation: modalities, advantages, and potential complications

Procedure/device	Mechanisms of LV unloading	Efficacy of LV unloading∗	Approach	Cost and complexity of application∗	Advantages	Disadvantages/complications
Noninvasive maneuvers
Reduced ECMO flow	Enhanced LV ejection/unloading (indirect)	✓–✓✓		✓	•Immediate action •Noninvasive procedure	•Reduced peripheral/organ perfusion
Modified ventilator settings (increased PEEP)	Increased right-sided drainage (indirect)	✓–✓✓		✓	•Immediate action •Noninvasive procedure	•Increased RV afterload •Increased barotrauma
Diuretics	Reduced cardiac loading (indirect)	✓–✓✓		✓	•Noninvasive procedure •Reduced extravascular volume •Improved lung gas exchange	•Reduced intravascular volume •Time needed to be effective •Preserved and responsive renal function required •Worsening of renal function
Hemofiltration	Reduced cardiac loading (indirect)	✓✓		✓✓	•Limited invasiveness •Usually already in place for concomitant renal failure •Limited personnel required for management	•Infection •Dependent on patient's hemodynamics •Bleeding •Excessive volume reduction reducing ECMO system loading
Inotropes	Enhanced LV ejection (indirect)	✓✓		✓	•Immediate action •Noninvasive procedure	•Increased myocardial o2 consumption •Ischemia induction •Myocardial stunning •Vasoconstriction (if part of the properties of the agent) •Heart rhythm/heart rate disturbances
Systemic vasodilation	Enhanced LV ejection (indirect)	✓–✓✓		✓	•Noninvasive procedure	•Reduced perfusion pressure •Increased peripheral volume sequestration
Invasive maneuvers
Extracardiac procedures
IABP	Reduced LV afterload (enhanced systolic ejection) and reduced LV end-diastolic pressure (enhanced left atrium and pulmonary veins unloading; indirect)	✓	Percutaneous, femoral (or surgical in case of specific adverse conditions, like severe peripheral vascular disease requiring an axillary or transaortic implant)	✓✓	•Prolonged use •Partial LV support when ECMO removed •Percutaneous implant •Not expensive •No major complications •Not personnel-dependent •User-friendly	•Limb ischemia •Vascular access bleeding •Emboli •If malpositioned (low), it might occlude bowel or renal arteries
Transaortic procedures
Percutaneous LV assist devices (Impella 2.5, CP, 5.0, and 5.5)	LV blood suction (direct)	✓✓✓✓✓		✓✓✓✓✓	•No stasis in the left cardiac chambers and aortic root •LV support when ECMO removed	•Hemolysis •Vascular access bleeding •Required personnel •Cost/expensive •When used in patients with VSD, it might reverse intraseptal shunting (from left-to-right, to right-to-left) •Contraindicated with a mechanical aortic valve
			Percutaneous, femoral		Impella 2.5 and CP
					•Quick percutaneous placement	•Less effective LV support •Higher risk of potential dislodgment
			Surgical, trans-subclavian or axillary, or aortic		Impella 5.0 and 5.5
					•Prolonged LV support (>2 wk) •Axillary/subclavian artery access allowing patient mobilization	•Lower risk of hemolysis compared with Impella CP or 2.5 •Higher risk of vascular access-related bleeding
Transaortic catheter	LV blood suction (direct)	✓✓✓✓✓	Percutaneous, femoral	✓✓✓✓	•No stasis in the left cardiac chambers and aortic root	•When used in patients with VSD, it might reverse intraseptal shunting (from left-to-right, to right-to-left) •Air embolism
Transapical dual-lumen cannula (ProtekDuo)	LV unloading (direct)	✓✓✓✓	•Surgical (left minithoracotomy) •Cannula through the cardiac apex up to the ascending aorta	✓✓✓✓	•Not very expensive •Controllable flow •Usable for short or prolonged support •With or without oxygenator •No stasis in the left cardiac chamber and aortic root	•Limited published experience (only 1 case report) •Bleeding •Myocardial infarction •Emboli •Infection •Contraindicated with a mechanical aortic valve •Limited expertise
Transaortic pump (PulseCath i-VAC)	LV blood ejection (direct)	✓✓✓	Percutaneous, femoral	✓✓✓	•No stasis in the left cardiac chambers and aortic root	•Potential limb ischemia •Vascular access bleeding •Limited expertise
LV apex procedures
Transapical or transmitral valve catheter	LV unloading (direct)	✓✓✓✓✓	•Surgical (left minithoracotomy) •Catheter in the left ventricle	✓✓✓✓	•Not expensive •Controllable •Can provide long-lasting support (apex/subclavian artery configuration—VAD-like mode)	•Surgical procedure required •Bleeding •Myocardial infarction •Emboli •Aortic valve closure and aortic root stasis and thrombosis •Infection •Air embolism
Trans-septal or biatrial procedures
Percutaneous septostomy usually with ballooning or stenting	•Left-to-right atrial shunt •Increased right atrial drainage (indirect)	✓✓✓	Percutaneous, femoral (venous access)	✓✓✓ (For all procedures)	•Not expensive •Can avoid need for indwelling device	•Expertise required •Residual ASD (in some cases to be closed after ECMO weaning) •Not controllable/nonmaneuverable shunt
Left atrium procedures
Trans-septal or interatrial groove, or left atrial roof, or right superior pulmonary vein catheter or cannula attached to the ECMO venous return	•Left atrium unloading •LV unloading and unloading of the pulmonary veins (indirect)	✓✓✓✓	Surgical (either via sternotomy or right minithoracotomy)	✓✓✓✓	•Easily performed in the operating room	•Surgical or septostomy-guided procedure •Systemic emboli •LV perforation •Bleeding •Extreme LV unloading with minimal or absent forward LV ejection (risk for intraventricular or aortic root stasis and thrombosis)
TandemHeart	Left atrium unloading LV unloading and unloading of the pulmonary veins (indirect)	✓✓✓✓	Percutaneous, femoral (venous access) or surgical (only arterial access)	✓✓✓✓✓	•Percutaneous approach	•Septostomy-guided procedure •Bleeding •Extreme LV unloading with minimal or absent forward LV ejection (risk for intraventricular or aortic root stasis and thrombosis)
Pulmonary artery procedures
Pulmonary artery cannula surgically or percutaneously placed	•Increased right-side blood drainage •Unloading of pulmonary veins and left cardiac chambers (indirect)	✓✓	Percutaneous (right internal jugular vein) or surgical, sternotomy (direct or through a vascular prosthesis)	✓✓✓	•Effective reduction of pulmonary vein flow (immediate solution of pulmonary edema) •Use as perfusion port (for RV dedicated support or to solve north/south (Harlequin) syndrome in VAV ECMO configuration)	•Risk of perforating the RV or PA •Effect of main blood drainage on the PA-related drainage and risk of low flow with thrombosis of the cannula •Extreme LV unloading with minimal or absent forward LV ejection (risk for intraventricular or aortic root stasis and thrombosis) •Increased ECMO flow with increased LV afterload
Increased systemic venous blood drainage (additional cannulas)
Systemic vein (femoral, jugular, subclavian) or right atrium	•Increased right-side blood drainage •Unloading of pulmonary veins and left cardiac chambers (indirect)	✓✓	Percutaneous (venous access) or sternotomy (central access)	✓✓✓	•Easily applicable •No specialty expertise required	•Bleeding from the new cannulation site •Extreme LV unloading with minimal or absent forward LV ejection (risk for intraventricular or aortic root stasis and thrombosis) •Increased ECMO flow with increased LV afterload

Impella devices are from Abiomed; ProtekDuo is from TandemLife/LivaNova; PulseCath i-VAC is from PulseCath BV; and TandemHeart is from LivaNova. Adapted from Lorusso.⁸LV, Left ventricular; ECMO, extracorporeal membrane oxygenation; PEEP, positive end expiratory pressure; RV, right ventricular; IABP, intra-aortic balloon pump; VSD, ventricular septal defect; VAD, ventricular assist device; ASD, atrial septal defect; VAV, veno-arterial-venous; PA, pulmonary artery.

^∗Grade from least (✓) to most powerful (✓✓✓✓✓).