Splanchnic ultrasound to guide unloading in VA-ECMO.

Ambulatory simultaneous venoarterial extracorporeal membrane oxygenation and temporary percutaneous left ventricular assist device bridge to heart transplantation

ELSO Interim Guidelines for Venoarterial Extracorporeal Membrane Oxygenation in Adult Cardiac Patients.

2] Over the past decade, there has been an increase in the use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in the management of refractory cardiogenic shock, because it offers not only a high cardiac output with biventricular support but also respiratory support. 5 However, peripheral VA-ECMO is limited by the significant increase in afterload because of retrograde aortic flow, which may be deleterious in CS, especially from AMI. The IABP has remained the most commonly used modality of LV decompression studied in literature because of its ubiquitous availability, ease of insertion, relatively small arteriotomy, theoretical benefit of diastolic augmentation and therefore coronary perfusion, and lastly, the ease of maintenance in the cardiac intensive care unit.

To Vent or Not to Vent: A Loaded Question During Venoarterial Extracorporeal Membrane Oxygenation Support for Cardiogenic Shock

Meta-Analysis on Left Ventricular Unloading With Impella in Patients With Cardiogenic Shock Receiving Venoarterial Extracorporeal Membrane Oxygenation

Routine Unloading in Patients Treated With Extracorporeal Membrane Oxygenation for Cardiogenic Shock: Mixed Outcomes Set the Stage for Future Trials.

The new heart allocation policy places veno-arterial extracorporeal membrane oxygenation (VA-ECMO)-supported heart transplant (HT) candidates at the highest priority status. Despite increasing evidence supporting left ventricular (LV) unloading during VA-ECMO, the effect of LV unloading on transplant outcomes following bridging to HT with VA-ECMO remains unknown. From October 18, 2018 to March 21, 2023, 624 patients on VA-ECMO at the time of HT were identified in the United Network for Organ Sharing database and were divided into 2 groups: VA-ECMO alone (N=384) versus VA-ECMO with LV unloading (N=240). Subanalysis was performed in the LV unloading group: Impella (N=106) versus intra-aortic balloon pump (N=134). Recipient age was younger in the VA-ECMO alone group (48 versus 53 years, P=0.018), as was donor age (VA-ECMO alone, 29 years versus LV unloading, 32 years, P=0.041). One-year survival was comparable between groups (VA-ECMO alone, 88.0±1.8% versus LV unloading, 90.4±2.1%; P=0.92). Multivariable Cox hazard model showed LV unloading was not associated with posttransplant mortality after HT (hazard ratio, 0.92; P=0.70). Different LV unloading methods had similar 1-year survival (intra-aortic balloon pump, 89.2±3.0% versus Impella, 92.4±2.8%; P=0.65). Posttransplant survival was comparable between different Impella versions (Impella 2.5, versus Impella CP, versus Impella 5.0, versus Impella 5.5). Under the current allocation policy, LV unloading did not impact waitlist outcome and posttransplant survival in patients bridged to HT with VA-ECMO, nor did mode of LV unloading. This highlights the importance of a tailored approach in HT candidates on VA-ECMO, where routine LV unloading may not be universally necessary.

The aim of this study was to quantify and understand the unloading effect of percutaneous balloon atrial septostomy (BAS) in acute cardiogenic shock (CS) treated with venoarterial (VA) extracorporeal membranous oxygenation (ECMO). In CS treated with VA ECMO, increased left ventricular (LV) afterload is observed that commonly interferes with myocardial recovery or even promotes further LV deterioration. Several techniques for LV unloading exist, but the optimal strategy and the actual extent of such procedures have not been fully disclosed. In a porcine model (n=11; weight 56kg [53-58 kg]), CS was induced by coronary artery balloon occlusion (57minutes [53-64 minutes]). Then, a step-up VA ECMO protocol (40-80mL/kg/min) was run before and after percutaneous BAS was performed. LV pressure-volume loops and multiple hemoglobin saturation data were evaluated. The Wilcoxon rank sum test was used to assess individual variable differences. Immediately after BAS while on VA ECMO support, LV work decreased significantly: pressure-volume area, end-diastolic pressure, and stroke volume to ∼78% and end-systolic pressure to ∼86%, while superior vena cava and tissue oximetry did not change. During elevating VA ECMO support (40-80mL/kg/min) with BAS vs without BAS, we observed 1) significantly less mechanical work increase (122% vs 172%); 2) no end-diastolic volume increase (100% vs 111%); and 3) a considerable increase in end-systolic pressure (134% vs 144%). In acute CS supported by VA ECMO, atrial septostomy is an effective LV unloading tool. LV pressure is akey component of LV work load, so whenever LV work reduction is a priority, arterial pressure should carefully be titrated low while maintaining organ perfusion.

A Single-Center Experience with Balloon Atrial Septostomy as an Unloading Strategy in Patients on ECMO

Background: Venoarterial-extracorporeal membrane oxygenation (VA-ECMO) is used to treat cardiogenic shock. However, retrograde arterial perfusion from the femoral artery can increase left ventricular (LV) afterload, resulting in LV distention which may hamper myocardial recovery and worsen pulmonary congestion. An intra-aortic balloon pump (IABP) can mitigate LV afterload, and Impella (Abiomed, Danvers, MA) can directly unload LV pressure. This study aimed to evaluate the efficacy of LV support devices during VA-ECMO in patients with cardiogenic shock. Methods: We retrospectively collected data from 213 consecutive patients treated with VA-ECMO due to cariogenic shock at our institution between January 2013 and December 2023. Patients were categorized as either receiving VA-ECMO alone or VA-ECMO with an LV support device. The LV support device was characterized as VA-ECMO with IABP or Impella. Data were analyzed for mortality, weaning from VA-ECMO, and changes in pulmonary congestion using the congestion score index (CSI), which is a semi-quantitative approach to pulmonary congestion based on a 6-zone evaluation of chest radiography, scoring each zone from 0 (no congestion) to 3 (intense pulmonary edema). Results: In this study, 95 patients received VA-ECMO alone, whereas 118 patients received an LV support device (101 VA-ECMO with IABP and 17 VA-ECMO with Impella). LV support devices improved weaning from VA-ECMO (odds ratio, 3.09 [95% confidence interval (CI), 1.75–5.55]; p<0.0001) whereas there was no difference in IABP versus Impella cohorts. Compared with VA-ECMO alone, patients with VA-ECMO with an LV support device had better survival at 30 days (OR, 3.04 [95% CI, 1.73–5.43]; p<0.0001). The rate of survival to discharge was better in VA-ECMO with an LV support device versus VA-ECMO alone (hazard ratio, 2.51 [95% CI, 1.72–3.65]; p<0.0001). The evaluation of pulmonary congestion using the CSI revealed that congestion significantly improved in VA-ECMO with Impella (changes of CSI: 1.86 to 1.36) but not in VA-ECMO with IABP (1.80 to 1.96) and VA-ECMO alone (1.94 to 2.14). Conclusion: An LV support device may be associated with reduced mortality and increased success in weaning off VA-ECMO in patients with cardiogenic shock. Impella may be particularly effective in reducing pulmonary congestion.

Hybrid and parallel extracorporeal membrane oxygenation circuits

Plugging the Hole: Diagnosis and Management of Post–Myocardial Infarction Ventricular Septal Defect

Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an effective mechanical circulatory support for cardiac insufficiency following cardiac surgery especially cardiac surgery with extracorporeal circulation, which can quickly restore the perfusion of vital organs. However, retrograde blood flow in the aorta during VA-ECMO may lead to increased left ventricular (LV) afterload, elevated LV filling pressure, mitral insufficiency, and elevated left atrial pressure, which may subsequently result in reduced coronary blood flow and pulmonary edema, thus aggravating the patient’s condition. Therefore, LV unloading is necessary during VA-ECMO. The optimal approach for LV unloading remains undefined, but the percutaneous access has been increasingly used over time. To addresss this issue, we have attempted to use cannulation of the subclavian artery for left ventricular unloading during VA-ECMO. This study aims to describe our method and report the preliminary results in three patients. Methods: Three patients with low cardiac output syndrome after cardiac surgery. All 3 patients had difficulty weaning from cardiopulmonary bypass (CPB) due to overfilling and contractile weakness of the heart, low mean arterial pressure<80mmHg, and left atrial pressure of >20 mmHg. Decision was made to start ECMO support immediately, and LV unloading was initiated via cannulation of the subclavian artery (Table 1). Given the differences in the surgical approaches and condition of patients, three methods were used to achieve LV unloading via the subclavian artery.Methods of LV unloading with cannulation via the subclavian artery during VA-ECMO in three patients with low cardiac output syndrome after cardiac surgery: 1) VA-ECMO with LV unloading via subclavian artery; 2) femoral vein-to-subclavian artery VA-ECMO with LV unloading via a 4-branched graft; 3) LV bypass via femoral artery-subclavian artery. Results: In all patients, the subclavian artery cannula was withdrawn at postoperative days 2-3, and ECMO was successfully weaned on postoperative day 4. One patient developed cardiac tamponade within 24 hour of surgery, echocardiography showed an LVEF of 55%. During an exploratory thoracotomy, a large amount of blood clot about 500 mL was found in the pericardium and removed, and the patient recovered uneventfully. Table 2 summarizes the postoperative courses of the 3 patients with different LV unloading methods. Conclusion: This study partly illustrated that LV drainage via the subclavian artery could safely and effectively reduce the LV load, prevent VA-ECMO-related complications, and minimize the risk of trauma and infection during LV examinations. Certainly, whether the subclavian artery approach is the optimal strategy for LV unloading as well as patient risks and benefits remains to be further investigated.Figure 1. ECMO + LV unloading schematic diagram of Case 1 (femoral artery + femoral vein+ subclavian artery)Figure 2. ECMO + LV unloading schematic diagram of Case 2 (femoral artery + femoral vein + four branches aortic graft)Figure 3. LV unloading schematic diagram of Case 2 (femoral artery + subclavian artery)

Intra-aortic balloon pump as a vent in VA-ECMO; lower risk, but beware

Early Versus Bail-Out Left Ventricular Unloading During Venoarterial Extracorporeal Membrane Oxygenation: A Systematic Review And Meta-Analysis.