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Case Reports

Left Ventricle Unloading Through Pulmonary Artery in Patients With Venoarterial Extracorporeal Membrane Oxygenation

de Pommereau, Aurélien*; Radu, Costin; Boukantar, Madjid*; Bagate, François; Mouillet, Gauthier*; Folliguet, Thierry; Mekontso Dessap, Armand; Teiger, Emmanuel*; Gallet, Romain*

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doi: 10.1097/MAT.0000000000001179
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Abstract

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) initiation for patients with cardiogenic shock or cardiac arrest is an attractive strategy since it provides a quick restoration of organ perfusion.1 However, VA-ECMO can lead to an increase in left ventricle (LV) and left atrial (LA) pressures associated with LV distension. This phenomenon may have severe consequences including coronary perfusion decrease and pulmonary edema, thus creating a vicious circle. Accordingly, LV distension in patients with VA-ECMO is associated with poor prognosis.2 To avoid this major limitation of VA-ECMO—LA or LV decompression may be required. Several strategies have been described for left heart decompression including surgical (atrial cannulation) or percutaneous approach (interatrial septostomy, intra-aortic balloon pump [IABP], or outflow pump Impella-Abiomed, Danvers, MA). Nevertheless, these approaches have some contraindications, carry a high risk of complications and, for some of them (IABP), concerns remain regarding their effectiveness.3

To overcome these limitations, the concept of indirect LV unloading through pulmonary artery venting has been described in children4 and intraoperatively during cardiopulmonary bypass.5 However, it has been poorly used in adults under VA-ECMO to date. We here describe our experience in two adult patients with refractory myocardial dysfunction in whom indirect LV unloading was performed for the prevention and the treatment of LV distension, respectively.

Technique

Using the modified Seldinger technique, a right internal jugular vein access was obtained. Under fluoroscopic guidance, a 0.35 starter guidewire (Boston Scientific, Marlborough, MA) was positioned into the pulmonary artery and then substituted with an Amplatzer Super Stiff guidewire (Boston Scientific) using a Judkins right 5 Fr catheter. A 14 Fr venous cannula (Medtronic, Minneapolis, MN) was advanced over the Amplatzer Super Stiff guidewire (Boston Scientific) into the pulmonary trunk. The cannula was then connected to the venous ECMO circuit with a “Y” connector (Figure 1A).

Figure 1.
Figure 1.:
Left-ventricle unloading using pulmonary venting in patients with VA-ECMO. A: Schematic illustration of VA-ECMO and pulmonary artery venting. B: Chest x-ray showing the preexisting venous ECMO cannula in the right atrium (star) and the venting cannula in the pulmonary artery trunk (arrow). C and D: Chest x-ray preunloading (C) and postunloading (D) showing the resolution of the pulmonary edema. VA-ECMO, venoarterial extracorporeal membrane oxygenation.

This type of unloading can also be achieved using dual lumen cannula (one for the right atrium and one for the pulmonary artery) but the latter is more expensive and optimal positioning may be more hazardous.

Case 1

A 49-year-old woman with no known history of cardiovascular disease before presentation was referred to our institution for a ST-elevation myocardial infarction (STEMI) requiring primary percutaneous coronary intervention (PCI) (Table 1). The patient presented a refractory cardiac arrest and rapid cannulation of the femoral vessels was performed for VA-ECMO support initiation. Coronary angiography revealed a left anterior descending artery occlusion that was successfully treated. Given the severe LV dysfunction associated with a post cardiac arrest resuscitation syndrome, we decided to preventively unload the LV immediately after the initiation of ECMO. Pulmonary venting was used because of the impossibility of femoral arterial vascular access. The pulmonary artery cannula was successfully positioned and the cannulation was completed in 24 minutes (Figure 1B). The patient had favorable clinical evolution with a decrease in inotrope needs following LV unloading, a decrease of arterial lactates and no occurrence of pulmonary edema. The patient was weaned from LV unloading and VA-ECMO on day 13 and day 49, respectively. The patient was discharged from hospital with a partial myocardial recovery, without requiring an LV assist device or heart transplant, and is still alive to date (follow-up 31 months) with an improvement of left ventricular ejection fraction (LVEF) to 42%.

Table 1. - Baseline Characteristics, Procedural Details, and Outcomes of Patient 1
Patient 1
Age (years) 49
Sex Female
Cause of cardiogenic shock STEMI
Cardiac arrest Yes
Coronary artery angioplasty Yes: LAD + RCA
Initial LVEF 15%
LV thrombus before LA venting No
Time from FMC to angioplasty-ECMO-LV venting 5 hours-2 hours-5.5 hours
Procedure time of LA venting 24 minutes
Po 2/Fio 2 pre-D1-D5 (mm Hg/%) 90/80-123/90-95/50
Lactates pre-D1-D5 (mmol/L) 18-5.3-0.8
ECMO flow pre-D5 (L/min) 3.5-0
Norepinephrine pre-D1-D5 (mg/hr) 7-0-0.4
Duration of ECMO-LV unloading (days) 5-5
LV unloading complication No
Duration of ventilation (days) 13
Patient outcomes Weaned from ECMO
Length of stay (days) 32
Alive at discharge Yes
LVEF at discharge 30%
Neurologic sequel at discharge No
D1-D5, days post left ventricular unloading; ECMO, extracorporeal membrane oxygenation; Fio2, fraction of inspired oxygen; FMC, first medical contact; LA, left atrial; LAD, left anterior descending artery; LV, left ventricular; LVEF, left ventricular ejection fraction; post venting, immediately succeeding to the left ventricular unloading; PO2, partial pressure of oxygen; pre, immediately before the left ventricular unloading; RCA, right coronary artery; STEMI, ST-elevation myocardial infarction.

Case 2

A 52-year-old woman with no history of cardiovascular disease was referred to our institution for a STEMI requiring primary PCI (Table 2). Coronary angiography revealed acute occlusion of the left anterior descending artery and of the right coronary artery that were both successfully treated. Despite the angioplasties, refractory cardiogenic shock occurred and peripheral VA-ECMO support was initiated using right percutaneous femoral access. LV function progressively weakened after VA-ECMO initiation leading to refractory pulmonary edema requiring LV unloading at day 6. We decided to perform LV unloading using pulmonary venting because of the presence of an LV thrombus possibly associated with an aortic thrombus. The pulmonary artery cannula was successfully positioned in 22 minutes. To assess the quality of LV unloading, hemodynamic measurements were performed before and after LV unloading using a Swan-Ganz pulmonary catheter (Edwards, Irvine, CA). Decompression was associated with a rapid decrease in pulmonary capillary wedge pressure (from 33 to 12 mm Hg). Furthermore, clinical evolution was good with a decrease in inotrope needs, a decrease of arterial lactates and a resolution of pulmonary edema (Figure 1, C and D). The patient was weaned from LV unloading on day 11 and from VA-ECMO on day 49. The patient was eventually discharged from hospital without requiring an LV assist device or heart transplant. She is still alive to date (11 months follow-up) with an improvement of LVEF to 45%.

Table 2. - Baseline Characteristics, Procedural Details, and Outcomes of Patient 2
Patient 2
Age (years) 52
Sex Female
Cause of cardiogenic shock STEMI
Cardiac arrest No
Coronary artery angioplasty Yes: LAD + RCA
Initial LVEF <20%
LV thrombus before LA venting Yes
Time from FMC to angioplasty/ECMO/LV venting 3 hours/4 hours/6 days
Procedure time of LA venting 22 minutes
MPAP pre-venting-post venting (mm Hg) 33-13
PCWP pre-venting-post venting (mm Hg) 33-12
SAP pre-venting-post venting (mm Hg) 110-119
DAP pre-venting-post venting (mm Hg) 80-97
MAP pre-venting-post venting (mm Hg) 85-102
Po 2/Fio 2 pre-D1-D5 (mm Hg/%) 44/100-115/100-217/50
Lactates pre-D1-D5 (mmol/L) 2.4-2.0-1.2
ECMO flow pre-D1-D5 (L/min) 4.6-5-3
Norepinephrine pre-D1-D5 (mg/hr) 0.6-0.8-0
Duration of ECMO-LV unloading (days) 41-11
LV unloading complication No
Duration of ventilation (days) 49
Patient outcomes Weaned from ECMO
Length of stay (days) 121
Alive at discharge Yes
LVEF at discharge 40%
Neurologic sequel at discharge No
D1-D5, days post left ventricular unloading; DAP, diastolic arterial blood pressure; ECMO, extracorporeal membrane oxygenation; Fio2, fraction of inspired oxygen; FMC, first medical contact; LA, left atrial; LAD, left anterior descending artery; LV, left ventricular; LVEF, left ventricular ejection fraction; MAP, mean arterial pressure; MPAP, mean pulmonary arterial pressure; PCWP, pulmonary capillary wedge pressure; post venting, immediately succeeding to the left ventricular unloading; PO2, partial pressure of oxygen; pre, immediately before the left ventricular unloading; RCA, right coronary artery; SAP, systolic arterial blood pressure; STEMI, ST-elevation myocardial infarction.

Discussion

LV distention occurs as a result of a major limitation on ECMO with potential catastrophic consequences. Here we have reported two cases suggesting the feasibility, safety, and efficacy of percutaneous placement of a venting cannula in the pulmonary artery trunk for LV unloading. In these two cases, pulmonary artery venting was performed rapidly and was successful for both the prevention and the treatment of LV distension related pulmonary edema.

The main contributory source of LV volume in patients on VA-ECMO is impaired systemic venous drainage. In these two cases, VA-ECMO was employed using peripheral cannulation. As previously described, these cannulae are longer and have a smaller diameter, thus increasing cannula impedance.5 This results in an incomplete right-sided drainage that will be responsible for an antegrade transpulmonary blood flow that will preload the LV. Moreover, bronchial and thebesian returns further preload the LV, albeit moderately. Therefore, VA-ECMO is, in this case, unable to unload either side of the circulation. In both our cases, there was no other significant source of volume into the LV. No intracardiac shunt or aortopulmonary shunt was observed. Furthermore, no significant aortic regurgitation that might have increased LV preload was present. Therefore, LV distension (that occurred in patient 2 and could have occurred in patient 1) was related to the LV depressed contractility resulting in an inability to open the aortic valve, associated with the presence of a source of LV preload, the impaired venous drainage. The placement of a venting cannula in the pulmonary artery trunk was able to respectively treat and prevent this LV distension.

Conclusions

LV distension in patients with VA-ECMO can be safely and effectively treated by the percutaneous placement of a venting cannula in the pulmonary artery trunk. More data are required to confirm the safety and efficacy of pulmonary artery venting and to determine its optimal indication and timing in patients with VA-ECMO.

References

1. Lazzeri C, Bernardo P, Sori A, et al. Venous-arterial extracorporeal membrane oxygenation for refractory cardiac arrest: A clinical challenge. Eur Heart J Acute Cardiovasc Care. 2013; 2:118–126
2. Guglin M, Burchett A, Tribble T, Charnigo R. Pulmonary congestion (white lungs) on VA ECMO. VAD J. 2:2016. doi: 10.13023/VAD.2016.04.
3. Schroeter T, Vollroth M, Hoebartner M, et al. Extracorporeal membrane oxygenation and intra-aortic ballon pump – an appropriate combination or useless battle of materials? Thorac Cardiovasc Surg. 2013; 61:OP19doi: 10.1055/s-0032-1332258.
4. Fouilloux V, Lebrun L, Macé L, Kreitmann B. Extracorporeal membranous oxygenation and left atrial decompression: A fast and minimally invasive approach. Ann Thorac Surg. 2011; 91:1996–1997
5. Rajagopal K. Left ventricular distension in veno-arterial extracorporeal membrane oxygenation: From mechanics to therapies. ASAIO J. 2019; 65:1–10
Keywords:

extracorporeal membrane oxygenation; mechanical circulatory support; left ventricular unloading; pulmonary artery venting

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