Temporary mechanical circulatory support in infarct-related cardiogenic shock: an individual patient data meta-analysis of randomised trials with 6-month follow-up

Year in Review 2024: Noteworthy Literature in Cardiac Anesthesiology

The research findings relevant for Cardiac Anesthesiology studies published in 2024 involved key innovations in devices and gene therapy in addition to the expansion of transcatheter techniques for valve repair or replacement. We reviewed 447 relevant articles and selected 21 as the most noteworthy studies published in 2024. Themes that emerged from our review include the etiology and prevention of delirium or outcomes after mechanical circulatory support. Robust clinical outcome data now supports the use of microaxial flow devices for mechanical circulatory support for cardiogenic shock due to acute myocardial infarction. Pharmacology development presents colchicine as anti-inflammatory medication to prevent atrial fibrillation or intravenous amino acids for kidney protection after cardiopulmonary bypass. Technological advances include implantable wireless pacing-defibrillator devices, pulmonary artery pressure monitoring in heart failure patients, extracorporeal blood purification for preventing acute kidney injury and hypothermic oxygenated perfusion of the donor heart in heart transplantation. Transcatheter interventions on mitral or aortic valve were gaining advances over surgical procedures. Novel paradigms included treatments with gene therapy for cardiac amyloidosis or refractory angina and the emerging risk of microplastic exposure in cardiovascular events.

ECPella 5+ in Patients With Cardiogenic Shock: Potential for Improved Outcomes

The use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for temporary mechanical circulatory support (MCS) is a common treatment in patients with cardiogenic shock (CS) but is associated with high morbidity and mortality. The combination therapy of VA- ECMO and Impella (ECPella) results in better outcomes. Currently, multiple generations of Impella are available for use in ECPella, however limited data exist to compare devices. Here, we explored whether ECPella 5+ adds further benefit to patient outcomes. We reviewed published studies focused on ECPella in CS to summarize clinical outcomes specifically pertaining to ECPella 5+. Findings were compared to outcomes from a contemporary cohort of 10 patients admitted for cardiogenic shock and treated with ECPella 5+ between January 2022 and May 2023. We evaluated 84 studies published in Pubmed between January 2017 and October 2023. Of these, 24 articles were selected for full analysis. Use of ECPella 5+ increased over time, with more than 50% of patients receiving this configuration in studies published in 2023. Mortality rate for ECPella 5+ (reported in 5 of 24 studies) was 33% compared to 49% for all ECPella combinations. Mortality outcomes of our patient cohort were consistent with a rate of 30%. These findings suggest that Impella 5+ may further improve outcomes of ECPella. However, the interpretation is limited by the small sample size and the descriptive nature of the data. Further larger, prospective studies are needed to determine potential improvements in complication rates, VA-ECMO and inotropic therapy duration, and native heart recovery.

Resource utilization associated with extracorporeal membrane oxygenation vs. microaxial flow pump for infarct-related cardiogenic shock

AIMS

Microaxial flow pump and venoarterial extracorporeal membrane oxygenation (VA-ECMO) are increasingly used in infarct-related cardiogenic shock. This study provides a comparative overview of real-world resource utilization associated with these devices (PROSPERO: CRD42024505174).

METHODS AND RESULTS

EMBASE, MEDLINE, and Cochrane Library were sought from inception to 13 November 2024 for studies reporting at least one primary outcome, including intensive care unit (ICU) length of stay (LOS), hospital LOS, in-hospital costs, and discharge destination. In-hospital mortality was included as secondary outcome. This study was guided by the PRISMA-2020 guideline. Study selection and data extraction were independently performed by two researchers. Risk-of-bias assessments were done using the Newcastle-Ottawa-Scale. Data were pooled using random-effect models. In total, 12 retrospective cohorts were identified encompassing 92 262 microaxial flow pump- and 16 474 VA-ECMO patients data. The meta-analysis of hospital LOS and in-hospital costs revealed favourable results for the microaxial flow pump, with mean differences (MD) of -5.3 days (95% CI: -6.6, -4.1) and -$113 983 (95% CI: -$143 153, -$84 812), respectively. Microaxial flow pump survivors were also 45% more likely to be discharged home (95% CI: 1.28-1.64). Intensive care unit-length of stay was reported by one study, reporting a 10 days MD in favour of the microaxial flow pump. The averaged in-hospital mortality rates were 44% and 57% for the microaxial flow pump and VA-ECMO, respectively. An inherent limitation of observational studies is confounding by indication.

CONCLUSION

Microaxial flow pump was associated with lower resource utilization compared with VA-ECMO. Resource utilization should be incorporated in prospective RCTs and taken into account when considering these devices.

Outcomes with mechanical circulatory support devices among patients with mechanical complications of acute myocardial infarction

AIMS

The aim of this study is to examine the trends and outcomes of mechanical circulatory support (MCS) device use among patients with mechanical complications of acute myocardial infarction (AMI).

METHODS AND RESULTS

Using data from the National Inpatient Sample (a large admirative database in the USA) years 2016-20, we identified AMI admissions (ST-elevation and non-ST-elevation myocardial infarction) with mechanical complications (ventricular septal defect, free wall rupture, or papillary muscle rupture). Among 4 450 219 AMI patients, 7025 (0.2%) had a mechanical complication of which 3115 patients (44.3%) received at least one MCS device. There was a rising trend in MCS use (39.3% in 2016 to 48.9% in 2020, Ptrend = 0.02), but there was no corresponding reduction in the incidence of in-hospital mortality (36.9% in 2016 vs. 43.4% in 2020, Ptrend = 0.75). There was no significant difference in in-hospital mortality between those who received MCS vs. those who did not (48.4 vs. 34.5%, respectively).

CONCLUSION

In this large observational analysis of AMI hospitalizations, mechanical complications were rare and associated with very high in-hospital mortality. Although the use of MCS has increased, in-hospital mortality rates remain high even among patients who received MCS. Further investigations are needed to clarify the role of MCS devices among patients with mechanical complications of AMI.

Diastolic Perfusion Pressure Predicts Response to Inotropes and Vasopressors and Benefit From Mechanical Circulatory Support in Cardiogenic Shock

BACKGROUND

Hemodynamic response to escalation of vasoactive drugs has not been well-characterized in patients with cardiogenic shock (CS). We tested the hypothesis that lower diastolic perfusion pressure (DPP=diastolic blood pressure-right atrial pressure) was associated with more limited hemodynamic response to uptitration of vasoactive drugs and with possible benefit from early mechanical circulatory support in patients with CS.

METHODS

This study consisted of 2 parts: (1) we evaluated the relationship between baseline DPP and changes in cardiac power output index (CPOI) in response to increase in vasoactive drugs in a cohort of patients with CS (n=93) and (2) we compared all-cause mortality based on baseline DPP in a post hoc analysis of the ECMO-CS trial (Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock). CPOI responders were defined as postescalation CPOI ≥0.28 W/m2.

RESULTS

Vasoactive inotrope score escalated from 11.2±3.9 to 24.5±4.7. Escalation of vasoactive drugs was associated with increases in CPOI to 0.23±0.06 W/m2 (all P<0.001). Postescalation CPOI was directly related to baseline cardiac index and DPP. Baseline DPP discriminated CPO responders from nonresponders with an optimal cutoff of 37 mm Hg. Patients with baseline DPP ≥37 mm Hg had greater CPOI increase and lactate clearance. In the ECMO-CS trial, patients with DPP <37 mm Hg had lower mortality (hazard ratio, 0.37 [95% CI, 0.14-0.97]; P=0.044) with immediate venoarterial extracorporeal membrane oxygenation compared with early conservative management but no significant difference in the subgroup with DPP ≥37 mm Hg.

CONCLUSIONS

Lower DPP was associated with more limited hemodynamic response to escalation of vasoactive drugs and potentially greater benefit from early venoarterial extracorporeal membrane oxygenation in CS.

Optimising trial design for cardiogenic shock: insights from the sixth Critical Care Clinical Trialists Workshop

Despite substantial advancements in the management of cardiogenic shock, mortality rates remain greater than 40%. Trials have shown that increasing survival rates in cardiogenic shock is challenging. Even the most successful trials show 5-15% reductions in mortality, and gains have been restricted to acute myocardial infarction cardiogenic shock, representing approximately 5% of the population with cardiogenic shock. Trials studying pharmacological strategies in all populations with cardiogenic shock have been consistently neutral or negative. The reasons are complex and include heterogeneity in cardiogenic shock phenotypes, timing of patient inclusion, high prevalence of multiorgan failure and cardiac arrest, and unrealistic estimated treatment effects that restrict sample size with sometimes inadequate funding leading to underpowered trials. In June, 2024, international experts from the fields of cardiology, anaesthesiology, critical care medicine, biostatistics, government regulation of trials, and patient advocacy convened at the sixth Critical Care Clinical Trialists Workshop to reflect on how to improve the design of future randomised clinical trials in cardiogenic shock. This Position Paper summarises the results of discussions regarding what an optimal randomised controlled trial on cardiogenic shock should entail in terms of population selection, primary objectives, statistical analysis, and incorporation of the patient's perspective.

Mechanical circulatory support for patients with infarct-related cardiogenic shock: a state-of-the-art review

Acute myocardial infarction-related cardiogenic shock (AMI-CS) is a severe, life-threatening condition characterised by inadequate tissue perfusion due to the heart's inability to pump blood effectively. The pathophysiology of AMI-CS usually arises from the sudden loss of myocardial contractility, leading to a decrease in cardiac output and systemic hypoperfusion. In approximately 90% of AMI-CS cases, the left ventricle is the primary site of dysfunction.Despite early recognition and the implementation of strategies such as primary percutaneous coronary intervention, the mortality rate associated with AMI-CS remains alarmingly high, reflecting significant unmet clinical needs. A major challenge lies in identifying the optimal patient population for mechanical circulatory support (MCS) devices, as these interventions are costly and can lead to serious complications.This review provides a comprehensive overview of the pathophysiological mechanisms underlying AMI-CS, explores the current range of MCS devices available and offers an in-depth discussion on the balance of benefits and risks associated with these devices. By highlighting key evidence from recent studies, we aim to shed light on the clinical decision-making process and improve outcomes in this high-risk patient population.

Mechanical circulatory support: when, how, and for whom

Cardiogenic shock represents a critical condition in which the heart is unable to maintain adequate circulation leading to insufficient tissue perfusion and end-organ failure. Temporary mechanical circulatory support offers the potential to stabilize patients, provide a bridge-to-recovery, provide a bridge-to-decision, or facilitate definitive heart replacement therapies. Although randomized controlled trials have been performed in infarct-related cardiogenic shock and refractory cardiac arrest, the optimal timing, appropriate patient selection, and optimal implementation of these devices remain complex and predominantly based on observational data and expert consensus, especially in non-ischaemic shock. This review explores the details of 'when, how, and for whom' temporary mechanical circulatory support devices should be used, examining specific clinical scenarios, the mechanisms by which they operate, and the patient populations that may benefit. The review also highlights the many gaps in evidence and need for better understanding of the interaction between human biology and these devices.

Different Mechanical Circulatory Support Strategies for Infarct-Related Cardiogenic Shock: A Subanalysis of the ECLS-SHOCK Trial

BACKGROUND

Mechanical circulatory support (MCS) devices are frequently used in patients with acute myocardial infarction complicated by cardiogenic shock. In clinical practice, escalation of MCS device therapy is performed in a significant proportion of patients aiming to improve hemodynamic status.

OBJECTIVES

The aim of this study was to analyze outcomes of different MCS device strategies in the ECLS-SHOCK (Extracorporeal Life Support in Cardiogenic Shock) trial.

METHODS

The present subanalysis from the ECLS-SHOCK trial analyzed outcomes of patients treated with upfront extracorporeal life support (ECLS) only, bailout MCS, and escalated MCS therapy. The primary outcome was 30-day all-cause mortality.

RESULTS

Upfront ECLS only, bailout MCS, and escalated MCS therapy were used in 165 (78.9%), 54 (26.0%), and 27 (12.9%) patients, respectively. Thirty-day all-cause mortality was 44.8% (95% CI: 37.1%-52.8%), 61.1% (95% CI: 46.9%-74.1%), and 55.6% (95% CI: 35.3%-74.5%) in the upfront ECLS, bailout MCS, and escalated MCS group (P = 0.09). Need for renal replacement therapy was higher in the bailout MCS (35.2%; 95% CI: 22.7%-49.4%) than in upfront ECLS (7.3%; 95% CI: 3.8%-12.4%) and escalated MCS (14.8%; 95% CI: 4.2%-33.8%) (P < 0.001). Moderate or severe bleeding complications were similar in the upfront ECLS (25.5%; 95% CI: 19.0%-32.8%), bailout MCS (22.2%; 95% CI: 12.0%-35.6%), and escalated MCS (22.2%; 95% CI: 8.6%-42.3%) group (P = 0.86).

CONCLUSIONS

Bailout and escalated MCS therapy is associated with numerically higher 30-day mortality compared with upfront ECLS use only. Bailout MCS use is also associated with higher need for renal replacement therapy. (Extracorporeal Life Support in Cardiogenic Shock [ECLS-SHOCK]; NCT03637205).

Comparison of temporary mechanical circulatory support devices for patients with cardiogenic shock after acute myocardial infarction: A network meta-analysis of randomized controlled trials

BACKGROUND

Despite the high mortality of cardiogenic shock after acute myocardial infarction (AMI-CS), the comparative efficacy and safety of mechanical circulatory support (MCS) in patients with AMI-CS is unknown. This study aimed to compare the efficacy and safety of various MCS with initial medical therapy for AMI-CS patients.

METHODS

We searched PubMed and EMBASE in July 2024. Randomized controlled trials (RCTs) comparing at least any of the following 2 were included: initial medical therapy, intra-aortic balloon pump (IABP), percutaneous ventricular assist device (pVAD), or extracorporeal membrane oxygenation (ECMO). We performed a network meta-analysis using a frequentist approach. The primary outcome was mid-term (6-12 months) mortality. The secondary outcomes were short-term (30-day or in-hospital) mortality, major bleeding, and vascular complications.

RESULTS

We included a total of 1845 patients with AMI-CS from 14 RCTs. There was no significant difference in short-term mortality between the treatment groups. However, pVAD and ECMO were associated with higher risks of major bleeding and vascular complications compared to initial medical therapy. Compared to initial medical therapy, pVAD (hazard ratio [HR], 0.77; 95 % confidence interval [CI], 0.60-1.00; p = 0.054) and ECMO (HR, 0.51; 95 % CI, 0.26-1.01; p = 0.054) were associated with the marginal benefits in reducing mid-term mortality.

CONCLUSIONS

In our study, there was no significant benefits of MCS devices in reducing short-term mortality, and pVAD and ECMO were associated with a higher incidence of major bleeding and vascular complications. Although not statistically significant, MCS showed a favorable trend in mid-term mortality.

Response on Rapid Review to Inform Policy Guidance on Welsh Respiratory ECMO Provision

Internationally, extracorporeal membrane oxygenation (ECMO) is now a core and standard organ support tool to provide tertiary critical care and cardiac services within a network of hospitals and a key tool for running an effective and efficient cardio-respiratory pathways. The letter aims to put the spotlight on some of the missing clinical evidence on respiratory ECMO and including them will help to arrive at a better-informed national ECMO policy decision.

Echography monitoring in patients with temporary mechanical circulatory support

PURPOSE OF REVIEW

To examine the role of echocardiography in managing patients with refractory cardiogenic shock supported by temporary mechanical circulatory support (t-MCS) and provide practical recommendations to improve clinical practice.

RECENT FINDINGS

t-MCS devices are increasingly used to stabilize patients with refractory cardiogenic shock. Echocardiography, due to its accessibility and ability to assess both structural and functional aspects of heart failure, is ideally suited for daily bedside evaluation of cardiac function and t-MCS-myocardial interactions.

SUMMARY

From t-MCS initiation to liberation, echocardiography is essential to guide clinical decision-making. It aids in selecting the most appropriate t-MCS device, ensuring optimal positioning, and fine-tuning flow parameters in real-time based on native cardiac function and patient needs. Additionally, echocardiography is critical for identifying intracardiac complications and directing unloading strategies in venoarterial extracorporeal membrane oxygenation, particularly with very low residual ejection or aortic valve closure. Finally, the weaning process should be informed by comprehensive echocardiographic evaluations, aligned with international guidelines. These steps are outlined in this review, accompanied by clear and practical recommendations to enhance clinical practice.

Breaking Down Cardiogenic Shock: An Analytical Reflection on the DanGer-SHOCK and ECLS-SHOCK Trials

Mechanical circulatory support devices, particularly the microaxial flow pump (mAFP), have gained traction in managing cardiogenic shock in patients with acute myocardial infarction. However, trials like DanGer-SHOCK (Microaxial Flow Pump or Standard Care in Infarct-Related Cardiogenic Shock) and ECLS-SHOCK (Extracorporeal Life Support in Infarct Related Cardiogenic Shock) have reported differing outcomes, making it challenging to draw definitive conclusions. To explore this further, we conducted a comparative analysis of the 30-day and 6-month mortality rates from the DanGer-SHOCK and ECLS-SHOCK trials, examining differences in patient populations and risk profiles. The goal was to determine whether these differences could explain the conflicting outcomes or if the benefits observed in the DanGer-SHOCK trial were directly attributable to the mAFP strategy. One key finding is that, despite similar control group mortality rates, the intervention group in DanGer-SHOCK demonstrated a notably lower mortality rate at both 30 days and 6 months compared with the ECLS trial, with an absolute difference of approximately 8%. This benefit is not due to inherent risk differences but is instead attributed to the Impella-based strategy. Compared with standard care, mAFP data revealed a 7% mortality reduction at 30 days, which grew to 12.7% at 180 days, highlighting the long-term effectiveness of the mAFP strategy in maintaining hemodynamic stability and improving survival. These results suggest that, in cardiogenic shock management, the DanGer unloading strategy, when combined with percutaneous coronary intervention, plays a significant role in improving long-term survival through early intervention and ventricular unloading, independent of control group factors. Further research is needed to confirm the broader applicability of this approach in different patient populations.

The Role of Impella in Cardiogenic Shock Complicated by an Acute Myocardial Infarction: A Meta-Analysis

Background: Emerging evidence suggests the role of mechanical circulatory support (MCS) devices in the therapy of refractory cardiogenic shock (CS). However, largerandomized trials addressing the role of Impella in the therapy of infarct-associated CS are sparse. As such, evidence coming from comprehensive retrospective studies or meta-analyses is of major importance in order to clarify the role of the Impella device in this setting. Methods: Only clinical trials involving patients receiving Impella 2.5 and Impella CP for treatment of CS caused in terms of acute coronary syndrome (ACS) were included in this meta-analysis. The primary endpoint was 30-day mortality, with major bleeding and ischemic vascular complications serving as secondary endpoints. Results: A total of 18 observational retrospective studies (2617 patients with CS and Impella implantation) were included in this analysis. The mean age of the total participants was 64.7 ± 2.93 years. A mean mortality incidence of 45% was found between all included participants. The ischemia rate was in total 8.5 ± 4.4%, and the incidence of bleeding was 13.9 ± 5.6%. Conclusions: The 30-day mortality rate for patients with ACS-associated CS treated with Impella remains high. The high complication rates underline the importance of Impella use in only a very well-selected population of patients.

Clinical Review of Cardiogenic Shock After Acute Myocardial Infarction - Revascularization, Mechanical Circulatory Support, and Beyond

Owing to recent advances in early reperfusion and pharmacological therapies, the prognosis of patients with acute myocardial infarction (AMI) has considerably improved over the past decades. However, the mortality rate remains high at ~40-50% after AMI when complicated by cardiogenic shock. Although immediate coronary revascularization of the infarct-related artery has been the only evidence-based treatment, temporary mechanical circulatory support with a microaxial flow pump (Impella) has become another therapeutic option supported by randomized trial data in highly selected patients. Here we summarize the latest evidence concerning clinical challenges in patients with AMI and cardiogenic shock.

Microaxial Flow Pump Hemodynamic and Metabolic Effects in Infarct-Related Cardiogenic Shock: A Substudy of the DanGer Shock Randomized Clinical Trial

Importance

Mechanical circulatory support with a microaxial flow pump (MAFP) has been shown to improve survival in ST-elevation myocardial infarction-induced cardiogenic shock (STEMI-CS). Understanding the impact on hemodynamic stability over time is crucial for optimizing patient treatment.

Objective

To determine if an MAFP reduces the need for pharmacological circulatory support without compromising hemodynamics compared with standard care in STEMI-CS.

Design, Setting, and Participants

This was a substudy of the Danish-German (DanGer) Shock trial, an international, multicenter, open-label randomized clinical trial. Patients from 14 heart centers across Denmark, Germany, and the UK were enrolled. Inclusion criteria for the trial were STEMI and systolic blood pressure less than 100 mm Hg or ongoing vasopressor treatment, left ventricular ejection fraction less than 45%, and arterial lactate level greater than 2.5 mmol/L. Of the enrolled patients, after exclusions from death in the catheterization laboratory or immediately on intensive care unit (ICU) admission, the remaining patients had serial recordings of hemodynamics, arterial lactate, and use of vasoactive drugs. Patients who were in comas after cardiac arrest and patients with mechanical complications or right ventricular failure were excluded. Data were analyzed from May to September 2024.

Interventions

MAFP and standard of care or standard of care alone.

Main Outcomes and Measures

Hemodynamic status in terms of heart rate and blood pressure, metabolic status in terms of arterial lactate concentration, and vasoactive-inotropic score (VIS). The clinical events during the first 72 hours were as follows: death from all causes, escalation of mechanical circulatory support, and discharge alive from the ICU.

Results

From 355 enrolled patients, 324 (mean [IQR] age, 68 [58-75] years; 259 male [80%]) underwent ICU treatment (169 [52%] in the MAFP group, 155 [48%] in the standard-care group). Baseline characteristics were balanced. There was no difference in heart rate between groups, and mean arterial pressure was above the treatment target of 65 mm Hg in both groups but was achieved with a lower VIS in the MAFP group. No difference in arterial lactate level was found between groups at randomization, but on arrival to the ICU, the MAFP group had significantly lower arterial lactate levels compared with the standard-care group (mean difference, 1.3 mmol/L; 95% CI, 0.7-1.9 mmol/L), a difference that persisted throughout the first 24 hours of observation. The MAFP group achieved lactate normalization (<2 mmol/L) 12 hours (95% CI, 5-18 hours) before the standard-care group.

Conclusions and Relevance

Use of a MAFP reduces the use of vasopressors and inotropic medication while maintaining hemodynamic stability and achieving faster normalization of lactate level in patients with STEMI-CS.

Trial Registration

ClinicalTrials.gov Identifier: NCT01633502.