Clinical Pearls of Venoarterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock

Current role of extracorporeal membrane oxygenation for the management of trauma patients: Indications and results

Extracorporeal membrane oxygenation (ECMO) has emerged as a vital circulatory life support measure for patients with critical cardiac or pulmonary conditions unresponsive to conventional therapies. ECMO allows blood to be extracted from a patient and introduced to a machine that oxygenates blood and removes carbon dioxide. This blood is then reintroduced into the patient’s circulatory system. This process makes ECMO essential for treating various medical conditions, both as a standalone therapy and as adjuvant therapy. Veno-venous (VV) ECMO primarily supports respiratory function and indicates respiratory distress. Simultaneously, veno-arterial (VA) ECMO provides hemodynamic and respiratory support and is suitable for cardiac-related complications. This study reviews recent literature to elucidate the evolving role of ECMO in trauma care, considering its procedural intricacies, indications, contraindications, and associated complications. Notably, the use of ECMO in trauma patients, particularly for acute respiratory distress syndrome and cardiogenic shock, has demonstrated promising outcomes despite challenges such as anticoagulation management and complications such as acute kidney injury, bleeding, thrombosis, and hemolysis. Some studies have shown that VV ECMO was associated with significantly higher survival rates than conventional mechanical ventilation, whereas other studies have reported that VA ECMO was associated with lower survival rates than VV ECMO. ECMO plays a critical role in managing trauma patients, particularly those with acute respiratory failure. Further research is necessary to explore the full potential of ECMO in trauma care. Clinicians should have a clear understanding of the indications and contraindications for the use of ECMO to maximize its benefits in treating trauma patients.

Infected Thrombosis Leading to Veno-Venous Extracorporeal Membrane Oxygenation Dysfunction in Chronic Thromboembolic Pulmonary Hypertension

Nosocomial infections and thrombosis are frequent complications during extracorporeal membrane oxygenation (ECMO). Preventative measures and close monitoring for early recognition of these complications are imperative in patients supported with ECMO. We report the case of a 41 year old female on veno-venous ECMO awaiting surgical thrombectomy for chronic thromboembolic pulmonary hypertension that developed profound bacteremia leading to gross purulence and thrombosis of the membrane oxygenator. Recannulation in addition to targeted antibiotics, frequent cultures, imaging, and surgery were diagnostic and therapeutic interventions that led to ultimate resolution.

Left ventricle unloading during veno-arterial extracorporeal membrane oxygenation: review with updated evidence

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is widely used to treat medically refractory cardiogenic shock and cardiac arrest, and its usage has increased exponentially over time. Although VA-ECMO has many advantages over other mechanical circulatory supports, it has the unavoidable disadvantage of increasing retrograde arterial flow in the afterload, which causes left ventricular (LV) overload and can lead to undesirable consequences during VA-ECMO treatment. Weak or no antegrade flow without sufficient opening of the aortic valve increases the LV end-diastolic pressure, and that can cause refractory pulmonary edema, blood stagnation, thrombosis, and refractory ventricular arrhythmia. This hemodynamic change is also related to an increase in myocardial energy consumption and poor recovery, making LV unloading an essential management issue during VA-ECMO treatment. The principal factors in effective LV unloading are its timing, indications, and modalities. In this article, we review why LV unloading is required, when it is indicated, and how it can be achieved.

Left ventricular unloading to facilitate ventricular remodelling in heart failure: A narrative review of mechanical circulatory support

Heart failure represents a dynamic clinical challenge with the continuous rise of a multi-morbid and ageing population. Yet, the evolving nature of mechanical circulatory support offers a variety of means to manage candidates who might benefit from such interventions. This narrative review focuses on the role of the main mechanical circulatory support devices, such as ventricular assist device, extracorporeal membrane oxygenation, Impella and TandemHeart, in the physiological process of ventricular unloading and remodelling in heart failure, highlighting their characteristics, mechanism and clinical outcomes. The outcome measures described include physiological changes (i.e., stroke volume or preload and afterload), intracardiac pressure (i.e., end-diastolic pressure) and extracardiac pressure (i.e., pulmonary capillary wedge pressure). Overall, all the above mechanical circulatory support strategies can facilitate the unloading of the ventricular failure through different mechanisms, which subsequently affects the ventricular remodelling process. These physiological changes start immediately after ventricular assist device implantation. The devices are indicated in different but overlapping populations and operate in distinctive ways; yet, they have evidenced performance to a favourable standard to improve cardiac function in heart failure, although this proved variable for different devices, and further high-quality trials are vital to assess their clinical outcomes further. Both Impella and TandemHeart are indicated mainly in cardiogenic shock and high-risk percutaneous coronary intervention patients; at the time the literature was evaluated, both devices were found to yield a significant improvement in haemodynamics but not in survival. Nevertheless, the choice of device strategy should be based on individual patient factors, including indication, to optimize clinical outcomes.

Acute Compartment Syndrome in Pediatric Patients on Extracorporeal Membrane Oxygenation Support

BACKGROUND

When acute compartment syndrome (ACS) occurs in pediatric patients requiring venoarterial extracorporeal membrane oxygen (VA ECMO) support, there is little data to guide surgeons on appropriate management. The purpose of this study is to characterize the presentation, diagnosis, timeline, and outcomes of patients who developed this complication.

METHODS

This is a single-center retrospective case series of children below 19 years old on VA ECMO support who subsequently developed extremity ACS between January 2016 and December 2022. Outcomes included fasciotomy findings, amputation, mortality, and documented function at the last follow-up.

RESULTS

Of 343 patients on VA ECMO support, 18 (5.2%) were diagnosed with ACS a median 29 hours after starting ECMO. Initial cannulation sites included 8 femoral, 6 neck, and 4 central. Femoral artery cannulation was associated with an increased risk of ACS [odds ratio=6.0 (CI: 2.2 to 15), P <0.0001]. In the hospital, the mortality rate was 56% (10/18). Fourteen (78%) patients received fasciotomies a median of 1.2 hours after ACS diagnosis. Only 4 (29%) patients had all healthy muscles at initial fasciotomy, while 9 (64%) had poor muscular findings in at least 1 compartment. Patients with worse findings at fasciotomy had a significantly longer duration between ischemia onset and ACS diagnosis. Patients required a median of 1.5 additional procedures after fasciotomy, and only 1 (7%) developed a surgical site infection. Of the 7 surviving fasciotomy patients, 2 required amputations, 3 developed an equinus contracture, 1 developed foot drop, and 3 had no ACS-related deficits. Four patients did not receive fasciotomies: 3 were deemed too ill and later died, and 1 was diagnosed too late to benefit. The only surviving nonfasciotomy patient required bilateral amputations.

CONCLUSIONS

Pediatric ECMO-associated ACS is not exclusive to patients with femoral artery cannulation. The majority of fasciotomy patients were diagnosed with ACS after muscle necrosis had already started. We were unable to definitively conclude whether fasciotomies provide better outcomes. There is a need for increased awareness and earlier recognition of this rare yet potentially devastating complication.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

A mock circulation loop to evaluate differential hypoxemia during peripheral venoarterial extracorporeal membrane oxygenation

INTRODUCTION

Peripheral veno-arterial extracorporeal membrane oxygenation (VA ECMO) creates a retrograde flow along the aorta competing with the left ventricle (LV) in the so-called 'mixing zone' (MZ). Detecting it is essential to understand which of the LV or the ECMO flow perfuses the upper body - particularly the brain and the coronary arteries - in case of differential hypoxemia (DH).

METHODS

We described a mock circulation loop (MCL) that enabled experimental research on DH. We recreated the three clinical situations relevant to clinicians: where the brain is either totally perfused by the ECMO or the LV or both. In a second step, we used this model to investigate two scenarios to diagnose DH: (i) pulse pressure and (ii) thermodilution via injection of cold saline in the ECMO circuit.

RESULTS

The presented MCL was able to reproduce the three relevant mixing zones within the aortic arch, thus allowing to study DH. Pulse pressure was unable to detect location of the MZ. However, the thermodilution method was able to detect whether the brain was totally perfused by the ECMO or not.

CONCLUSION

We validated an in-vitro differential hypoxemia model of cardiogenic shock supported by VA ECMO. This MCL could be used as an alternative to animal studies for research scenarios.

Extracorporeal membrane oxygenation for cardiac arrest: what, when, why, and how

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) facilitated resuscitation was first described in the 1960s, but only recently garnered increased attention with large observational studies and randomized trials evaluating its use.

AREAS COVERED

In this comprehensive review of extracorporeal cardiopulmonary resuscitation (ECPR), we report the history of resuscitative ECMO, terminology, circuit configuration and cannulation considerations, complications, selection criteria, implementation and management, and important considerations for the provider. We review the relevant guidelines, different approaches to cannulation, postresuscitation management, and expected outcomes, including neurologic, cardiac, and hospital survival. Finally, we advocate for the participation in national/international Registries in order to facilitate continuous quality improvement and support scientific discovery in this evolving area.

EXPERT OPINION

ECPR is the most disruptive technology in cardiac arrest resuscitation since high-quality CPR itself. ECPR has demonstrated that it can provide up to 30% increased odds of survival for refractory cardiac arrest, in tightly restricted systems and for select patients. It is also clear, though, from recent trials that ECPR will not confer this high survival when implemented in less tightly protocoled settings and within lower volume environments. Over the next 10 years, ECPR research will explore the optimal initiation thresholds, best practices for implementation, and postresuscitation care.

Early Low Pulse Pressure in VA-ECMO Is Associated with Acute Brain Injury

BACKGROUND

Pulse pressure is a dynamic marker of cardiovascular function and is often impaired in patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO). Pulsatile blood flow also serves as a regulator of vascular endothelium, and continuous-flow mechanical circulatory support can lead to endothelial dysfunction. We explored the impact of early low pulse pressure on occurrence of acute brain injury (ABI) in VA-ECMO.

METHODS

We conducted a retrospective analysis of adults with VA-ECMO at a tertiary care center between July 2016 and January 2021. Patients underwent standardized multimodal neuromonitoring throughout ECMO support. ABI included intracranial hemorrhage, ischemic stroke, hypoxic ischemic brain injury, cerebral edema, seizure, and brain death. Blood pressures were recorded every 15 min. Low pulse pressure was defined as a median pulse pressure < 20 mm Hg in the first 12 h of ECMO. Multivariable logistic regression was performed to investigate the association between pulse pressure and ABI.

RESULTS

We analyzed 5138 blood pressure measurements from 123 (median age 63; 63% male) VA-ECMO patients (54% peripheral; 46% central cannulation), of whom 41 (33%) experienced ABI. Individual ABIs were as follows: ischemic stroke (n = 18, 15%), hypoxic ischemic brain injury (n = 14, 11%), seizure (n = 8, 7%), intracranial hemorrhage (n = 7, 6%), cerebral edema (n = 7, 6%), and brain death (n = 2, 2%). Fifty-eight (47%) patients had low pulse pressure. In a multivariable model adjusting for preselected covariates, including cannulation strategy (central vs. peripheral), lactate on ECMO day 1, and left ventricle venting strategy, low pulse pressure was independently associated with ABI (adjusted odds ratio 2.57, 95% confidence interval 1.05-6.24). In a model with the same covariates, every 10-mm Hg decrease in pulse pressure was associated with 31% increased odds of ABI (95% confidence interval 1.01-1.68). In a sensitivity analysis model adjusting for systolic pressure, pulse pressure remained significantly associated with ABI.

CONCLUSIONS

Early low pulse pressure (< 20 mm Hg) was associated with ABI in VA-ECMO patients. Low pulse pressure may serve as a marker of ABI risk, which necessitates close neuromonitoring for early detection.

Effect of venoarterial extracorporeal membrane oxygenation initiation timing on tricuspid valve surgery outcomes

Objectives

Tricuspid valve surgery is associated with high rates of shock and in-hospital mortality. Early initiation of venoarterial extracorporeal membrane oxygenation after surgery may provide right ventricular support and improve survival. We evaluated mortality in patients undergoing tricuspid valve surgery based on the timing of venoarterial extracorporeal membrane oxygenation.

Methods

All consecutive adult patients undergoing isolated or combined surgical tricuspid valve repair or replacement from 2010 to 2022 requiring venoarterial extracorporeal membrane oxygenation use were stratified by initiation in the operating room (Early) versus outside of the operating room (Late). Variables associated with in-hospital mortality were explored using logistic regression.

Results

There were 47 patients who required venoarterial extracorporeal membrane oxygenation: 31 Early and 16 Late. Mean age was 55.6 years (standard deviation, 16.8), 25 (54.3%) were in New York Heart Association class III/IV, 30 (60.8%) had left-sided valve disease, and 11 (23.4%) had undergone prior cardiac surgery. Median left ventricular ejection fraction was 60.0% (interquartile range, 45-65), right ventricular size was moderately to severely increased in 26 patients (60.5%), and right ventricular function was moderately to severely reduced in 24 patients (51.1%). Concomitant left-sided valve surgery was performed in 25 patients (53.2%). There were no differences in baseline characteristics or invasive measurements immediately before surgery between the Early and Late groups. Venoarterial extracorporeal membrane oxygenation was initiated 194 (23.0-840.0) minutes after cardiopulmonary bypass in the Late venoarterial extracorporeal membrane oxygenation group. In-hospital mortality was 35.5% (n = 11) in the Early group versus 68.8% (n = 11) in the Late group (P = .037). Late venoarterial extracorporeal membrane oxygenation was associated with in-hospital mortality (odds ratio, 4.00; 1.10-14.50; P = .035).

Conclusions

Early postoperative initiation of venoarterial extracorporeal membrane oxygenation after tricuspid valve surgery in high-risk patients may be associated with improvement in postoperative hemodynamics and in-hospital mortality.

'Goal-directed extracorporeal circulation: transferring the knowledge and experience from daily cardiac surgery to extracorporeal membrane oxygenation'

Metabolism management plays an essential role in extracorporeal technologies. There are different metabolic management devices integrated to extracorporeal devices; the most commonly used and accepted metabolic target in adult patients is indexed oxygen delivery (280 mL/min/m²) and cardiac index (2.4 L/min/m²), which can be managed independently or according to other metabolic parameters. Extracorporeal membrane oxygenation (ECMO) is a temporary form of life support providing a prolonged biventricular circulatory and pulmonary support for patients experiencing both pulmonary and cardiac failure unresponsive to conventional therapy. The goal-directed perfusion initiative during cardiopulmonary bypass (CPB) reduced the incidence of acute kidney injury after cardiac surgery. On the basis of the available literature, the identified goals to achieve during CPB include maintenance of oxygen delivery > 300 mL O₂/min/m² and reduction in vasopressor use. ECMO and CPB are conceptually similar but differ in many aspects and finality; in particular, they differ in the scientific evidence for metabolic management nadirs. As for CPB, predictive target parameters have been found and consolidated, particularly in terms of acute renal injury and the prevention of anaerobic metabolism, while for ECMO management, a blurred path remains. In this context, we review the strategies for optimal goal-directed therapy during CPB and ECMO, trying to transfer the knowledge and experience from daily cardiac surgery to veno-arterial ECMO.

Contralateral Lower Extremity Ischemia on Femoral Veno-Arterial Extracorporeal Membrane Oxygenation

Ipsilateral lower extremity ischemia is a common and morbid complication during veno-arterial extracorporeal membrane oxygenation (VA-ECMO). The cannula can impede ipsilateral distal arterial flow leading to critical limb ischemia. Cannula size, placement, and utilization of distal perfusion catheters are strategies that have been used to prevent this complication. We report the novel case of a 19-year-old female on VA-ECMO complicated by contralateral lower extremity ischemia. Diagnosis was made by computed tomography, and with repositioning of the femoral arterial cannula, she had a complete resolution of symptoms.

Knowledge gaps and research priorities in adult veno-arterial extracorporeal membrane oxygenation: a scoping review

PURPOSE

This scoping review aims to identify and describe knowledge gaps and research priorities in veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

An expert panel was recruited consisting of eight international experts from different backgrounds. First, a list of priority topics was made. Second, the panel developed structured questions using population, intervention, comparison and outcomes (PICO) format. All PICOs were scored and prioritized. For every selected PICO, a structured literature search was performed.

RESULTS

After an initial list of 49 topics, eight were scored as high-priority. For most of these selected topics, current literature is limited to observational studies, mainly consisting of retrospective cohorts. Only for ECPR and anticoagulation, randomized controlled trials (RCTs) have been performed or are ongoing. Per topic, a summary of the literature is stated including recommendations for further research.

CONCLUSIONS

This scoping review identifies and presents an overview of knowledge gaps and research priorities in VA-ECMO. Current literature is mostly limited to observational studies, although with increasing attention for this patient population, more RCTs are finishing or ongoing. Translational research, from preclinical trials to high-quality or randomized controlled trials, is important to improve the standard practices in this critically ill patient population. Take-home message This scoping review identifies and presents an overview of research gaps and priorities in VA-ECMO. Translational research, from preclinical trials to high-quality or randomized controlled trials, is important to improve the standard practices in this critically ill patient population.

The Disconnect Between Extracorporeal Circulation and the Microcirculation: A Review

Extracorporeal circulation (ECC) procedures, such as cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO), take over the function of one or more organs, providing clinicians time to treat underlying pathophysiological conditions. ECMO and CPB carry significant mortality rates for patients, despite prior decades of research focused on the resulting failure of critical organs. Since the focus of these procedures is to support blood flow and provide oxygen-rich blood to tissues, a shift in research toward the effects of ECMO and CPB on the microcirculation is warranted. Along with provoking systemic responses, both procedures disrupt the integrity of red blood cells, causing release of hemoglobin (Hb) from excessive foreign surface contact and mechanical stresses. The effects of hemolysis are especially pronounced in the microcirculation, where plasma Hb leads to nitric oxide scavenging, oxidization, formation of reactive oxygen species, and inflammatory responses. A limited number of studies have investigated the implications of ECMO in the microcirculation, but more work is needed to minimize ECMO-induced reduction of microcirculatory perfusion and consequently oxygenation. The following review presents existing information on the implications of ECMO and CPB on microvascular function and proposes future studies to understand and leverage key mechanisms to improve patient outcomes.

Impact of the inspiratory oxygen fraction on the cardiac output during jugulo-femoral venoarterial extracorporeal membrane oxygenation in the rat

Background

Venoarterial extracorporeal membrane oxygenation (V-A ECMO) with femoral access has gained wide acceptance in the treatment of critically ill patients. Since the patient´s cardiac output (CO) can compete with the retrograde aortic ECMO-flow, the aim of this study was to examine the impact of the inspiratory oxygen fraction on the cardiac function during V-A ECMO therapy.

Methods

Eighteen male Lewis rats (350–400 g) received V-A ECMO therapy. The inspiratory oxygen fraction on the ventilator was randomly set to 0.5 (group A), 0.21 (group B), or 0 in order to simulate apnea (group C), respectively. Each group consisted of six animals. Arterial blood pressure, central venous saturation (ScvO2), CO, stroke volume, left ventricular ejection fraction (LVEF), end diastolic volume, and pressure were measured. Cardiac injury was determined by analyzing the amount of lactate dehydrogenase (LDH).

Results

During anoxic ventilation the systolic, mean and diastolic arterial pressure, CO, stroke volume, LVEF and ScvO2 were significantly impaired compared to group A and B. The course of LDH values revealed no significant differences between the groups.

Conclusion

Anoxic ventilation during V-A ECMO with femoral cannulation leads to cardiogenic shock in rats. Therefore, awake V-A ECMO patients might be at risk for hypoxia-induced complications.

Risk Factors of paediatric Venoarterial Extracorporeal Membrane Oxygenation-Related gastrointestinal bleeding after Open Heart Surgeries

OBJECTIVE

To analyze the risk factors for gastrointestinal (GI) bleeding in congenital heart disease (CHD) patients supported with venoarterial extracorporeal membrane oxygenation (V-A ECMO) after open heart surgery.

METHODS

A retrospective analysis was performed on children with (GI group: 26 cases) and without (control group: 122 cases) GI bleeding during ECMO at Shanghai Children's Medical Center from 2017 to 2020. Clinical data were analyzed and compared between groups to search for risk factors for GI bleeding.

RESULTS

A total of 148 cases were included in the study.The overall incidence of GI bleeding was 17.6% (26/148). The in-hospital mortality rate in the GI group was 61.5% (16/26) vs. 45.9% (56/122) in the control group. Twenty-six patients suffered cardiac arrest before ECMO support. The GI bleeding incidence among extracorporeal cardiopulmonary resuscitation (ECPR) patients was 50.0% (13/26) vs. 28.7 (35/122) among non-ECPR patients, P=0.035. The activated clotting time (ACT) was 201.40 s (180.47 to 247.27) in the GI group vs. 177.63 s (167.79 to 203.13) (P = 0.050) in the control group. The lowest antithrombin level (Min AT) was 27.00±13.07% vs. 37.62±15.18 (P=0.001). The pH and lactate levels before ECMO (Pre PH and Pre Lac) were lower in the GI group than in the control group. (7.31±0.23 vs. 7.35±0.17, P=0.035 and 12.2±6.11 vs. 7.78±6.67, P=0.003). Liver function during ECMO support was statistically worse in the GI group than in the control group. Multivariate analysis showed that Pre Lac (OR = 1.106 [1.018-1.202], P=0.0016) was an independent risk factor for GI bleeding. ROC analysis of Pre Lac and GI bleeding showed an area under the curve (AUC) of 0.700 (95% CI: 0.600-0.800, P=0.002) and a cutoff value of 9.30 mmol/L (sensitivity, 73.1%; specificity, 62.7%).

CONCLUSIONS

As the first study in this field, the probability of GI bleeding and related mortality were found to be high in children supported with V-A ECMO after open heart surgery. A higher lactate level before ECMO was an independent risk factor for GI bleeding.

Postcardiotomy Extracorporeal Membrane Oxygenation in Neonates

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) provides circulatory support in children with congenital heart disease, particularly in the setting of cardiopulmonary failure and inability to wean from cardiopulmonary bypass. This study summarized the clinical application of ECMO in the treatment of heart failure after cardiac surgery in neonates.

MATERIALS AND METHODS

Clinical data of 23 neonates who received ECMO support in our center from January 2017 to June 2019 were retrospectively analyzed.

RESULTS

Twenty-three neonates, aged from 0 to 25 days and weight between 2,300 and 4,500 g, with heart failure postcardiotomy were supported with ECMO. The successful weaning rate was 78.26% and discharge rate was 52.17%. Bleeding and residual malformation were the most common complications. The univariate analysis showed that nonsurvivors were related to the factors such as higher lactate value of ECMO 12 and 24 hours (p = 0.008 and 0.001, respectively), longer time to lactate normalization (p = 0.001), lactate > 10 mmol/L before ECMO (p = 0.01), lower weight (p = 0.01), longer ECMO duration (p = 0.005), lower platelet count (p = 0.001), more surgical site bleeding (p = 0.001), and surgical residual malformation (p = 0.04). Further logistic regression analysis revealed that higher lactate value of ECMO 24 hours (p = 0.003), longer ECMO duration (p = 0.015), and surgical site bleeding (p = 0.025) were independent risk factors.

CONCLUSION

ECMO was an effective technology to support the neonates with cardiopulmonary failure after open heart surgery. Control the lactate acidosis and surgical site bleeding event may be helpful for patients' recovery.

Comparison of ECMO vs ECpella in patients with non post-pericardiotomy cardiogenic shock: An updated meta-analysis

INTRODUCTION

The impact of Impella and ECMO (ECPELLA) in cardiogenic shock (CS) remains to be defined. The aim of this meta-analysis is to evaluate the benefit of ECPELLA compared to VA-ECMO in patients with non post-pericardiotomy CS.

METHODS

All studies reporting short term outcomes of ECpella or VA ECMO in non post-pericardiotomy CS were included. The primary endpoint was 30-day mortality. Vascular and bleeding complications and LVAD implantation/heart transplant within 30-days were assessed as secondary outcomes.

RESULTS

Of 407 studies identified, 13 observational studies (13,682 patients, 13,270 with ECMO and 412 with ECpella) were included in this analysis. 30-day mortality was 55.8% (51.6-59.9) in the VA-ECMO group and 58.3% (53.5-63.0) in the ECpella group. At meta-regression analysis the implantation of IABP did not affect mortality in the ECMO group. The rate of major bleeding in patients on VA-ECMO and ECpella support were 21.3% (16.9-26.5) and 33.1% (25.9-41.2) respectively, while the rates of the composite outcome of LVAD implantation and heart transplantation within 30-days in patients on VA-ECMO and ECpella support were 14.4% (9.0-22.2) and 10.8%. When directly compared in 3 studies, ECpella showed a positive effect on 30-day mortality compared to ECMO (OR: 1.81: 1.039-3.159).

CONCLUSION

Our data suggest that ECpella may reduce 30-day mortality and increase left ventricle recovery, despite increased of bleeding rates.

Treatment of Cardiovascular Dysfunction With PDE5-Inhibitors - Temperature Dependent Effects on Transport and Metabolism of cAMP and cGMP

Introduction

Cardiovascular dysfunction is a potentially lethal complication of hypothermia. Due to a knowledge gap, pharmacological interventions are not recommended at core temperatures below 30°C. Yet, further cooling is induced in surgical procedures and survival of accidental hypothermia is reported after rewarming from below 15°C, advocating a need for evidence-based treatment guidelines. In vivo studies have proposed vasodilation and afterload reduction through arteriole smooth muscle cGMP-elevation as a favorable strategy to prevent cardiovascular dysfunction in hypothermia. Further development of treatment guidelines demand information about temperature-dependent changes in pharmacological effects of clinically relevant vasodilators.

Materials and Methods

Human phosphodiesterase-enzymes and inverted erythrocytes were utilized to evaluate how vasodilators sildenafil and vardenafil affected cellular efflux and enzymatic breakdown of cAMP and cGMP, at 37°C, 34°C, 32°C, 28°C, 24°C, and 20°C. The ability of both drugs to reach their cytosolic site of action was assessed at the same temperatures. IC₅₀- and K_i-values were calculated from dose–response curves at all temperatures, to evaluate temperature-dependent effects of both drugs.

Results

Both drugs were able to reach the intracellular space at all hypothermic temperatures, with no reduction compared to normothermia. Sildenafil IC₅₀ and K_i-values increased during hypothermia for enzymatic breakdown of both cAMP (IC₅₀: 122 ± 18.9 μM at 37°C vs. 269 ± 14.7 μM at 20°C, p < 0.05) and cGMP (IC₅₀: 0.009 ± 0.000 μM at 37°C vs. 0.024 ± 0.004 μM at 32°C, p < 0.05), while no significant changes were detected for vardenafil. Neither of the drugs showed significant hypothermia-induced changes in IC₅₀ and K_i–values for inhibition of cellular cAMP and cGMP efflux.

Conclusion

Sildenafil and particularly vardenafil were ableto inhibit elimination of cGMP down to 20°C. As the cellular effects of these drugs can cause afterload reduction, they show potential in treating cardiovascular dysfunction during hypothermia. As in normothermia, both drugs showed higher selectivity for inhibition of cGMP-elimination than cAMP-elimination at low core temperatures, indicating that risk for cardiotoxic side effects is not increased by hypothermia.

Liberation From Venoarterial Extracorporeal Membrane Oxygenation: A Review

Venoarterial extracorporeal membrane oxygenation may be used for circulatory support in cardiogenic shock as a bridge to recovery, a bridge to a ventricular assist device (VAD), or a bridge to transplant. While the determination of potential exit strategies is essential before cannulation, the final determination of a patient's options may change, in part, through their in-hospital clinical course. We propose that liberation from venoarterial extracorporeal membrane oxygenation should be conceptualized as a process of discovery in the assessment of a patient's underlying clinical status and a key driver of further clinical decision-making. A trial of liberation from support should be considered when the goals of the weaning trial are well-defined and, ideally, in the absence of potentially confounding clinical factors. In this review, we will discuss readiness to wean criteria from venoarterial extracorporeal membrane oxygenation, as well as specific clinical, biochemical, and echocardiographic parameters that may prove useful in determining weaning timing and revealing the patient's underlying hemodynamic status and prognosis. The role of various cannula configurations, support devices, and pharmacological adjuncts will also be discussed. Finally, we highlight current gaps in evidence and suggest areas of future research.

Use of Extracorporeal Life Support for Heart Transplantation: Key Factors to Improve Outcome

Although patients receiving extracorporeal life support (ECLS) as a bridge to transplantation have demonstrated worse outcomes than those without ECLS, we investigated the key factors in the improvement of their posttransplant outcome. From December 2003 to December 2018, 257 adult patients who underwent heart transplantation (HTx) at our institution were included. We identified 100 patients (38.9%) who underwent HTx during ECLS (ECLS group). The primary outcome was 30-day mortality after HTx. The median duration of ECLS was 10.0 days. The 30-day mortality rate was 3.9% (9.2% in peripheral ECLS, 2.9% in central ECLS, and 1.9% in non-ECLS). The use of ECLS was not an independent predictor of 30-day and 1-year mortality (p = 0.248 and p = 0.882, respectively). Independent predictors of 30-day mortality were found to be higher ejection fraction (p < 0.001), Sequential Organ Failure Assessment score (p < 0.001), and total bilirubin level (p = 0.005). In a subgroup analysis, cannulation type was not a predictor of 30-day mortality (p = 0.275). Early ECLS application to prevent organ failure and sophisticated management of acute heart failure may be important steps in achieving favorable survival after HTx.

Veno-arterial extracorporeal membrane oxygenation: Special reference for use in 'post-cardiotomy cardiogenic shock' - A review with an Indian perspective

The ultimate goals of cardiovascular physiology are to ensure adequate end-organ perfusion to satisfy the local metabolic demand, to maintain homeostasis and achieve 'milieu intérieur'. Cardiogenic shock is a state of pump failure which results in tissue hypoperfusion and its associated complications. There are a wide variety of causes which lead to this deranged physiology, and one such important and common scenario is the post-cardiotomy state which is encountered in cardiac surgical units. Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an important modality of managing post-cardiotomy cardiogenic shock with variable outcomes which would otherwise be universally fatal. VA-ECMO is considered as a double-edged sword with the advantages of luxurious perfusion while providing an avenue for the failing heart to recover, but with the problems of anticoagulation, inflammatory and adverse systemic effects. Optimal outcomes after VA-ECMO are heavily reliant on a multitude of factors and require a multi-disciplinary team to handle them. This article aims to provide an insight into the pathophysiology of VA-ECMO, cannulation techniques, commonly encountered problems, monitoring, weaning strategies and ethical considerations along with a literature review of current evidence-based practices.

Mechanical Circulatory Support in Cardiogenic Shock due to Structural Heart Disease

Despite advances in cardiovascular care, managing cardiogenic shock caused by structural heart disease is challenging. Patients with cardiogenic shock are critically ill upon presentation and require early disease recognition and rapid escalation of care. Temporary mechanical circulatory support provides a higher level of care than current medical therapies such as vasopressors and inotropes. This review article focuses on the role of hemodynamic monitoring, mechanical circulatory support, and device selection in patients who present with cardiogenic shock due to structural heart disease. Early initiation of appropriate mechanical circulatory support may reduce morbidity and mortality.

The physiological basis of clinical decision-making in venoarterial extracorporeal life support

Venoarterial (VA) extracorporeal life support (ECLS) or extracorporeal membrane oxygenation (ECMO) as it is commonly known is used in many clinical situations to support both the pumping action of the heart and the gas exchange function of the lungs. This review hopes to refresh, in the mind of the reader, aspects of basic physiological principles that have relevance in VA ECLS therapy. The dynamics of the interaction of the machine with the patient and vice versa plays an important role in clinical outcome. An understanding of the variation from normal physiology imposed both by the machine and the disease process will help make enlightened decisions in the use of this challenging therapy. The key physiological changes during initiation, maintenance, and weaning are discussed as well as certain specific clinical scenarios.

Femoral venoarterial extracorporeal membrane oxygenation using a novel biatrial cannula for venous drainage and left ventricular venting

Extracorporeal life support (ECLS) is an expanding technology for patients in cardiogenic shock. The majority of patients requiring ECLS can be managed with percutaneous venoarterial (VA) femoral cannulation. Despite sufficient extracorporeal circulatory support, a unclear number of patients develop left ventricular distension which can result in increased wall tension and stress as well as worsening pulmonary edema. Indications to vent the left ventricle can be controversial. When venting is indicated, a number of additional procedures may be considered including inotropic support, intra-aortic balloon pump, impella, balloon atrial septostomy, or placement of a transseptal cannula. We present a unique case of a femoral VA extracorporeal membrane oxygenation as a bridge to transplant with left-sided venting using a Bio-Medicus NextGen cannula (Medtronic) with a transseptal approach.

The use of extracorporeal membrane oxygenation postcardiotomy-A systematic review

OBJECTIVES

The use of extracorporeal membrane oxygenation (ECMO) in cardiac surgery has been established in cases of postcardiotomy cardiogenic shock, which is refractory to conventional therapy with inotropes and intra-aortic balloon pulsation support. We sought to examine the literature in a systematic review manner on the outcomes of using ECMO postcardiac surgery.

METHODS

A comprehensive electronic literature search was done to identify all the articles that have discussed the use of ECMO postcardiac surgery. The keywords and medical subject headings terms were used to identify the relevant articles. Studies have been screened according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

The identified studies have been summarized in each relevant section of this study. Cardiogenic shock postcardiac surgery can benefit from ECMO to varying degrees and the survival for this; otherwise, fatal condition has been shown to be improving through the use of ECMO. However, the decision and timing to initiate ECMO therapy remains selective and is dependent on a range of factors such as patient factor, clinician's judgment, meaning there is no consistent and solid ground regarding the timing of ECMO initiation.

CONCLUSION

Current evidence suggests that the circulatory support provided by ECMO improves survival rates for postcardiac surgery cardiogenic shock patients who are refractory to inotropic management, without such ECMO support patient mortality rates would be much greater.

CPR and ECMO: The Next Frontier

Cardiopulmonary resuscitation (CPR) is a first-line therapy for sudden cardiac arrest, while extracorporeal membrane oxygenation (ECMO) has traditionally been used as a means of countering circulatory failure. However, new advances dictate that CPR and ECMO could be complementary for support after cardiac arrest. This review details the emerging science, technology, and clinical application that are enabling the new paradigm of these iconic circulatory support modalities in the setting of cardiac arrest.

Mechanical Circulatory Support for Acute Heart Failure Complicated by Cardiogenic Shock

Acute heart failure is a potentially life-threatening condition that can lead to cardiogenic shock, which is associated with hypotension and organ failure. Although there have been many studies on the treatment for cardiogenic shock, early mortality remains high at 40-50%. No new medicines for cardiogenic shock have been developed. Recently, there has been a gradual decline in the use of the intra-aortic balloon pump mainly due to a lack of adequate hemodynamic support. Extracorporeal membrane oxygenation and the percutaneous ventricular assist device have become more widely used in recent years. A thorough understanding of the mechanisms of such mechanical support devices and their hemodynamic effects, components of the devices, implantation technique, management, criteria for indications or contraindications of use, and clinical outcomes as well as multidisciplinary decision making may improve the outcomes in patients experiencing cardiogenic shock.