Subclavian Versus Femoral Arterial Cannulations During Extracorporeal Membrane Oxygenation: A Propensity-Matched Comparison

Comparison of the effects of phosphorylcholin versus heparin-based surface coating on clinical and histologic outcomes during veno-arterial extracorporeal membrane oxygenation support: a propensity score weighted analysis

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is associated with a high rate of thrombotic complications, which are prevented using systemic anticoagulation and surface coating technologies. Heparin and phosphorylcholin (PPC) coatings are widely used in clinical practice, but little is known about their effectiveness in VA-ECMO setting.

OBJECTIVES

To compare the effects of heparin and PPC coatings on thrombotic complications, bleeding, blood trauma, inflammation, thrombi composition, and mortality.

METHODS

A retrospective multicenter clinical cohort was studied for clinical endpoints, and a prospective histologic cohort was investigated for thrombi composition. The clinical cohort included adult patients supported by VA-ECMO for cardiogenic shock, without any constitutive or acquired hemostasis disease disorder, from January 2013 to December 2020. Thrombi retrieved from circuit junctions underwent histochemical and immunochemical analysis for erythrocytes, von Willebrand factor (VWF), platelets, fibrinogen, and neutrophil extracellular traps content. The clinical cohort was compared using a propensity score overlap weighting. A P value <.05 was significant.

RESULTS

Compared with PPC coating, heparin coating was associated with a lower incidence of thrombotic complications before and after propensity score overlap weighting (hazard ratio [HR]: 0.67; 95% CI: 0.48-0.93; P = .015), a lower decrease in hemoglobin, but a greater decrease in platelet count. In the histologic analysis, PPC coating resulted in a greater content of VWF. The other endpoints were similar among groups.

CONCLUSION

Compared with PPC coating, heparin coating is associated with fewer thrombotic complications during VA-ECMO support. Kinetics of platelet count and hemoglobin, thrombi contents differed according to coating types.

TRIAL REGISTRATION

The prospective substudy is ancillary to the WITECMO-H multicenter study registered at ClinicalTrial.gouv (NCT03070912).

Extracorporeal Membrane Oxygenation Cannulation Site Affects Coronary and Cerebral Perfusion When Combined With Intra-Aortic Balloon Pump

The use of intra-aortic balloon pump (IABP) alongside venoarterial extracorporeal membrane oxygenation (VA-ECMO) in critically ill patients presenting refractory cardiogenic shock raises questions regarding its impact on organs perfusion. This in vitro study aimed to examine the combined effects of IABP and VA-ECMO on coronary, cerebral, and renal perfusion, particularly considering the choice of arterial cannulation site. A mock circuit with a pulsatile pump was used to simulate different scenarios with increasing severities of low cardiac output syndromes treated by concomitant IABP and VA-ECMO support. Flow rates were measured using ultrasonic flowmeters. Each scenario was tested with two different VA-ECMO outflow access sites: femoral and axillary arteries, at heart rates of 60 and 100 bpm. Results showed that concomitant use of IABP with VA-ECMO in the axillary artery increases more significantly cerebral and coronary flow rates compared to femoral access in intermediate and severe shock. Nevertheless, renal perfusion appeared to be more negatively affected in this configuration. In summary, employing IABP alongside axillary VA-ECMO enhances cerebral and coronary flow but may compromise renal perfusion. Shock severity, heart rate, and cannulation site should be considered for a tailored approach. Future investigations using sophisticated autoregulated systems are needed to confirm these observations.

Femoro-axillary versus femoro-femoral veno-arterial extracorporeal membrane oxygenation for refractory cardiogenic shock: A monocentric retrospective study

RationaleFor veno-arterial extracorporeal membrane oxygenation (ECMO), the femoral artery is the preferred cannulation site (femoro-femoral: Vf-Af). This results in retrograde aortic flow, which increases the left ventricular afterload and can lead to severe pulmonary edema and thrombosis of the cardiac chambers. Right axillary artery cannulation (femoral-axillary: Vf-Aa) provides partial anterograde aortic flow, which may prevent some complications. This study aimed to compare the 90-day mortality and complication rates between VF-AA and VF-AF.MethodsConsecutive adult patients with cardiogenic shock who received peripheral VA-ECMO between 2013 and 2019 at our institution were retrospectively included. The exclusion criteria were refractory cardiac arrest, multiple VA-ECMO implantations due to vascular access changes, weaning failure, or ICU readmission. A statistical approach using inverse probability of treatment weighting was used to estimate the effect of the cannulation site on the outcomes. The primary endpoint was the 90-day mortality. The secondary endpoints were vascular access complications, stroke, and other complications related to retrograde blood flow. Outcomes were estimated using logistic regression analysis.ResultsVA-ECMO was performed on 534 patients. Patients with refractory cardiac arrest (n = 77 (14%)) and those supported by multiple VA-ECMO (n = 92, (17%)) were excluded. Out of the 333 patients studied (n = 209 Vf-Aa; n = 124 VF-AF), the main indications for VA-ECMO implantation were post-cardiotomy (33%, n = 109), dilated cardiomyopathy (20%, n = 66), post-cardiac transplantation (15%, n = 50), acute myocardial infarction (14%, n = 46) and other etiologies (18%, n = 62). The median SOFA score was 9 [7-11], and the crude 90-day mortality rate was 53% (n = 175). After IPTW, the 90-day mortality was similar in the Vf-Aa and VF-AF groups (54% vs 58%, IPTW-OR = 0.84 [0.54-1.29]). Axillary artery cannulation was associated with significantly fewer local infections (OR = 0.21, 95% CI:0.09-0.51), limb ischemia (OR = 0.37, 95% CI:0.17-0.84), bowel ischemia (OR = 0.16, 95% CI:0.05-0.51) and pulmonary edema (OR = 0.52, 95% CI:0.29-0.92) episodes, but with a higher rate of stroke (OR = 2.87, 95% CI:1.08-7.62) than femoral artery cannulation.ConclusionCompared to VF-AF, axillary cannulation was associated with similar 90-day mortality rates. The high rate of stroke associated with axillary artery cannulation requires further investigation.

Numerical Simulation of Fluid-Structure Interaction in Axillary Artery Venoarterial Extracorporeal Membrane Oxygenation for Heart Failure Patients

Although axillary artery venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been utilized as a mechanical circulatory support for patients with end-stage heart failure (HF), there is currently insufficient evidence to support its effectiveness and safety. The objective of this study was to analyze the hemodynamic effects of axillary artery VA-ECMO. To this end, we obtained CT angiographic imaging data of the aorta from a carefully selected heart failure patient with a cardiac output of 2.1 L/min. These data were used to construct a detailed fluid-structure interaction model of the aorta. Axillary artery VA-ECMO was then simulated within this model, maintaining a constant flow rate of 3 L/min. The intra-aortic balloon counterpulsation (IABP) balloon was simulated to inflate and deflate in synchrony with the diastolic and systolic phases of the cardiac cycle. Hemodynamic effects, including left ventricular (LV) pressure afterload, vessel wall stress, perfusion of vital organs, blood flow pulsatility, and the watershed region, were calculated using fluid-structure interaction analysis. We found that axillary artery VA-ECMO delivers well-distributed, oxygen-rich blood flow but may increase left ventricular (LV) afterload and reduce cerebral blood flow. However, when combined with IABP, it unloads LV pressure and increases cerebral blood flow. Integrating axillary artery VA-ECMO with IABP can promote cardiac function recovery and improve oxygen-rich blood perfusion to the vital organs of heart failure patients.

A randomized embedded multifactorial adaptive platform for extra corporeal membrane oxygenation (REMAP ECMO) - design and rationale of the left ventricular unloading trial domain

BACKGROUND

The use of Extracorporeal Membrane Oxygenation (ECMO) remains associated with high rates of complications, weaning failure and mortality which can be partly explained by a knowledge gap on how to properly manage patients on ECMO support. To address relevant patient management issues, we designed a "Randomized Embedded Multifactorial Adaptive Platform (REMAP)" in the setting of ECMO (REMAP ECMO) and a first embedded randomized controlled trial (RCT) investigating the effects of routine early left ventricular (LV) unloading through intra-aortic balloon pumping (IABP).

METHODS

REMAP ECMO describes a registry-based platform allowing for the embedding of multiple response adaptive RCTs (trial domains) which can perpetually address the effect of relevant patient management issues on ECMO weaning success. A first trial domain studies the effects of LV unloading by means of an IABP as an adjunct to veno-arterial (V-A) ECMO versus V-A ECMO alone on ECMO weaning success at 30 days in adult cardiogenic shock patients admitted to the Intensive Care Unit (ICU). The primary outcome of this trial is "successful weaning from ECMO" being defined as a composite of survival without the need for mechanical circulatory support, heart transplantation, or left ventricular assist device (LVAD) at 30 days after initiation of ECMO. Secondary outcomes include the need for interventional escalation of LV unloading strategy, mechanistic endpoints, survival characteristics until 1 year after ECMO initiation, and quality of life. Trial data will be analysed using a Bayesian statistical framework. The adaptive design allows for a high degree of flexibility, such as response adaptive randomization and early stopping of the trial for efficacy or futility. The REMAP ECMO LV unloading study is approved by the Medical Ethical Committee of the Erasmus Medical Center and is publicly registered.

CONCLUSION

This REMAP ECMO trial platform enables the efficient roll-out of multiple RCTs on relevant patient management issues. A first embedded trial domain will compare routine LV unloading by means of an IABP as an adjunct to V-A ECMO versus V-A ECMO alone.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05913622.

A Guide to Contrast-Enhanced Computed Tomography in Adult Patients Supported With Extracorporeal Membrane Oxygenation

Veno-arterial extracorporeal membrane oxygenation (VA ECMO) fundamentally alters patient physiology and blood flow relevant to contrast delivery for computed tomography (CT) imaging. Here, we present a comprehensive guide to contrast-enhanced CT scanning in adult ECMO patients, addressing common questions related to contrast delivery via the ECMO circuit, and modifications to ECMO settings and scanning techniques, to avoid non-diagnostic CT scans. The approach is described in detail for patients supported on VA ECMO, with the return cannula sited in the femoral artery. Lesser modifications required for veno-venous ECMO (VV ECMO) are included in the supplemental material. Establishing a common understanding between the intensive care clinician, the CT radiographer, and the radiologist, concerning the patient's blood-flow-physiology, is the overarching goal. Our stepwise approach facilitates clear communication around modifications to the ECMO pump settings, contrast route and rate, as well as the scanning technique, for each individual scenario.

Incidence and outcomes of prosthetic valve thrombosis during peripheral extracorporeal membrane oxygenation

OBJECTIVES

In the context of postcardiotomy cardiogenic shock (PCCS) following valve replacement surgery, it may be necessary to implant a peripheral veno-arterial extracorporeal membrane oxygenation (pVA-ECMO). This procedure, however, carries a risk of prosthetic valve thrombosis. The aim of this retrospective study was to describe the incidence and outcomes of prosthetic valve thrombosis after VA-ECMO support for PCCS and to report the associated risk factors.

METHODS

All consecutive adult patients who received pVA-ECMO for PCCS following a valve replacement procedure between January 2015 and October 2019 in our institution were included in this retrospective study. Outcome variables were prosthetic valve thrombosis, 30-day and hospital survival, pVA-ECMO-associated adverse events and surgery-related adverse events.

RESULTS

During the 4-year study period, 549 patients received pVA-ECMO for PCCS. Among them, 152 had undergone a valve replacement procedure and 9 of these developed prosthetic valve thrombosis. The incidence of valve thrombosis at 30 days was 7.5 ± 2%. The cumulative incidence of prosthetic valve thrombosis was significantly lower with pVA-ECMO + intra-aortic balloon pump versus VA-ECMO alone (1.4 ± 1.4% vs 13.7 ± 4.7%, P = 0.021, respectively). Intra-aortic balloon pump use associated with pVA-ECMO (versus pVA-ECMO alone) was an independent protective factor against hospital death [odds ratio = 0.180 (0.068-0.478), P = 0.001].

CONCLUSIONS

After PCCS following valve replacement surgery, peripheral femoro-femoral VA-ECMO is associated with a low risk of acute valve thrombosis especially when associated with an intra-aortic balloon pump.

The physiology of venoarterial extracorporeal membrane oxygenation - A comprehensive clinical perspective

Venoarterial extracorporeal membrane oxygenation (VA ECMO) has become a standard of care for severe cardiogenic shock, refractory cardiac arrest and related impending multiorgan failure. The widespread clinical use of this complex temporary circulatory support modality is still contrasted by a lack of formal scientific evidence in the current literature. This might at least in part be attributable to VA ECMO related complications, which may significantly impact on clinical outcome. In order to limit adverse effects of VA ECMO as much as possible an indepth understanding of the complex physiology during extracorporeally supported cardiogenic shock states is critically important. This review covers all relevant physiological aspects of VA ECMO interacting with the human body in detail. This, to provide a solid basis for health care professionals involved in the daily management of patients supported with VA ECMO and suffering from cardiogenic shock or cardiac arrest and impending multiorgan failure for the best possible care.

Lung Transplantation for Pulmonary Arterial Hypertension

TOPIC IMPORTANCE

Even though patients with pulmonary arterial hypertension have multiple therapeutic options, the disease can be refractory despite appropriate management. In patients with end-stage pulmonary arterial hypertension, lung transplantation has the potential both to extend survival and improve health-related quality of life. Pulmonary arterial hypertension is the only major diagnostic indication for transplantation that is not a parenchymal pulmonary process, and thus the care of these patients is unique.

REVIEW FINDINGS

This review focuses on the complexities of lung transplantation for patients with pulmonary arterial hypertension, presents the updated referral and listing criteria, and discusses the inequities in the organ allocation process that impact this disease group and the strategies to optimize outcomes for patients with pulmonary arterial hypertension who require lung transplantation.

SUMMARY

Lung transplantation is an effective and lifesaving therapy for patients with end-stage lung disease. Sadly, patients with pulmonary arterial hypertension face many challenges as it relates to transplantation including higher perioperative risks, inequities in the allocation system, and less favorable long-term outcomes. This review covers the complexities of transplantation in patients with pulmonary vascular disease.

The American Association for Thoracic Surgery (AATS) 2022 Expert Consensus Document: The use of mechanical circulatory support in lung transplantation

OBJECTIVE

The use of mechanical circulatory support (MCS) in lung transplantation has been steadily increasing over the prior decade, with evolving strategies for incorporating support in the preoperative, intraoperative, and postoperative settings. There is significant practice variability in the use of these techniques, however, and relatively limited data to help establish institutional protocols. The objective of the AATS Clinical Practice Standards Committee (CPSC) expert panel was to review the existing literature and establish recommendations about the use of MCS before, during, and after lung transplantation.

METHODS

The AATS CPSC assembled an expert panel of 16 lung transplantation physicians who developed a consensus document of recommendations. The panel was broken into subgroups focused on preoperative, intraoperative, and postoperative support, and each subgroup performed a focused literature review. These subgroups formulated recommendation statements for each subtopic, which were evaluated by the entire group. The statements were then developed via discussion among the panel and refined until consensus was achieved on each statement.

RESULTS

The expert panel achieved consensus on 36 recommendations for how and when to use MCS in lung transplantation. These recommendations included the use of veno-venous extracorporeal membrane oxygenation (ECMO) as a bridging strategy in the preoperative setting, a preference for central veno-arterial ECMO over traditional cardiopulmonary bypass during the transplantation procedure, and the benefit of supporting selected patients with MCS postoperatively.

CONCLUSIONS

Achieving optimal results in lung transplantation requires the use of a wide range of strategies. MCS provides an important mechanism for helping these critically ill patients through the peritransplantation period. Despite the complex nature of the decision making process in the treatment of these patients, the expert panel was able to achieve consensus on 36 recommendations. These recommendations should provide guidance for professionals involved in the care of end-stage lung disease patients considered for transplantation.

Early hyperoxia and 28-day mortality in patients on venoarterial ECMO support for refractory cardiogenic shock: a bicenter retrospective propensity score-weighted analysis

BACKGROUND

The mortality rate for a patient with a refractory cardiogenic shock on venoarterial (VA) extracorporeal membrane oxygenation (ECMO) remains high, and hyperoxia might worsen this prognosis. The objective of the present study was to evaluate the association between hyperoxia and 28-day mortality in this setting.

METHODS

We conducted a retrospective bicenter study in two French academic centers. The study population comprised adult patients admitted for refractory cardiogenic shock. The following arterial partial pressure of oxygen (PaO2) variables were recorded for 48 h following admission: the absolute peak PaO2 (the single highest value measured during the 48 h), the mean daily peak PaO2 (the mean of each day's peak values), the overall mean PaO2 (the mean of all values over 48 h), and the severity of hyperoxia (mild: PaO2 < 200 mmHg, moderate: PaO2 = 200-299 mmHg, severe: PaO2 ≥ 300 mmHg). The main outcome was the 28-day all-cause mortality. Inverse probability weighting (IPW) derived from propensity scores was used to reduce imbalances in baseline characteristics.

RESULTS

From January 2013 to January 2020, 430 patients were included and assessed. The 28-day mortality rate was 43%. The mean daily peak, absolute peak, and overall mean PaO2 values were significantly higher in non-survivors than in survivors. In a multivariate logistic regression analysis, the mean daily peak PaO2, absolute peak PaO2, and overall mean PaO2 were independent predictors of 28-day mortality (adjusted odds ratio [95% confidence interval per 10 mmHg increment: 2.65 [1.79-6.07], 2.36 [1.67-4.82], and 2.85 [1.12-7.37], respectively). After IPW, high level of oxygen remained significantly associated with 28-day mortality (OR = 1.41 [1.01-2.08]; P = 0.041).

CONCLUSIONS

High oxygen levels were associated with 28-day mortality in patients on VA-ECMO support for refractory cardiogenic shock. Our results confirm the need for large randomized controlled trials on this topic.