Timing of Impella implantation and outcomes in cardiogenic shock or high-risk percutaneous coronary revascularization

Review of Advancements in Managing Cardiogenic Shock: From Emergency Care Protocols to Long-Term Therapeutic Strategies

Cardiogenic shock (CS) is a complex multifactorial clinical syndrome of end-organ hypoperfusion that could be associated with multisystem organ failure, presenting a diverse range of causes and symptoms. Despite improving survival in recent years due to new advancements, CS still carries a high risk of severe morbidity and mortality. Recent research has focused on improving early detection and understanding of CS through standardized team approaches, detailed hemodynamic assessment, and selective use of temporary mechanical circulatory support devices, leading to better patient outcomes. This review examines CS pathophysiology, emerging classifications, current drug and device therapies, standardized team management strategies, and regionalized care systems aimed at optimizing shock outcomes. Furthermore, we identify gaps in knowledge and outline future research needs.

Mechanical Circulatory Support with Impella: Principles, Evidence, and Daily Practice

The Impella (Abiomed, Danvers, MA, USA) microaxial pump is a percutaneous mechanical circulatory support (MCS) that has been shown to increase coronary perfusion, reduce myocardial oxygen demand, and improve peripheral organ perfusion. Therefore, indications for the Impella device include emergency use for cardiogenic shock (CS) and pre-emptive implantation during high-risk percutaneous coronary intervention (HR-PCI). However, despite their exponential use in cardiovascular practice over the past decade, there is limited randomized evidence to support the benefits of this therapy and growing concern regarding complication rates. In this review, we summarize the principles, evidence, and practical considerations of the most widely used Impella CP percutaneous left ventricular support in both CS and HR-PCI settings, moving from the historical background to current issues and future expectations for this device.

The use of mechanical circulatory support in elective high-risk percutaneous coronary interventions: a literature-based review

Contemporary medical practices allow complete percutaneous coronary intervention (PCI) in a considerable number of patients who previously would have been considered too 'high-risk' for such procedures. The use of mechanical circulatory support (MCS) devices during these high-risk PCIs (HR-PCIs) is thought to reduce the potential risk for major adverse events during and after revascularization. The intra-aortic balloon pump (IABP), veno-arterial extracorporeal membrane oxygenation (V-A ECMO), and the Impella are the most common MCS devices in use. This review aims to summarize the clinical evidence for each of these devices and the potential mechanisms for the improvement in patient outcomes in HR-PCI. The IABP use has rapidly declined in recent years due to no evidence of benefit in HR-PCI and cardiogenic shock. The V-A ECMO results in low rates of major adverse cardiac and cerebrovascular events (MACCEs) but higher rates of acute kidney injury and increased need for transfusions. In initial studies, Impella resulted in a reduced need for repeat interventions and reduced rates of hypotension, but no benefit in mortality. However, MACCE rates with Impella have gradually declined over the last 10 years, reflecting increased operator experience and technical improvements. Thus, a large, randomized trial is needed to assess the efficacy of Impella in HR-PCI with contemporary standards of care. There is currently no individual parameter that can identify patients who would benefit from MCS use in elective HR-PCI. To address this gap, we propose an algorithm that combines anatomical complexity, comorbidities, and clinical presentation to accurately identify candidates for MCS-assisted HR-PCI.

Clinical characteristics and outcomes of patients requiring prolonged mechanical circulatory support after high-risk percutaneous coronary intervention

BACKGROUND

There are limited data on the clinical characteristics and outcomes of patients who require prolonged mechanical circulatory support (MCS) after Impella-supported high-risk percutaneous coronary intervention (HR-PCI).

AIMS

The aim of this study is to describe the contemporary clinical characteristics, outcomes, and predictors associated with prolonged MCS support after assisted HR-PCI.

METHODS

Patients enrolled in the prospective, multicentre, clinical endpoint-adjudicated PROTECT III study who had undergone HR-PCI using Impella were evaluated. Patient and procedural characteristics and outcomes for those who received prolonged MCS beyond the duration of their index procedure were compared to those in whom MCS was successfully weaned and explanted at the conclusion of the index PCI.

RESULTS

Among 1,155 patients who underwent HR-PCI with Impella between 2017 and 2020 and had sufficient data to confirm the duration of Impella support, 16.5% received prolonged MCS (mean duration 25.2±31.1 hours compared with 1.8±5.8 hours for those who only received intraprocedural MCS). Patients receiving prolonged support presented with more urgent indications (e.g., acute coronary syndromes [ACS], lower ejection fraction [EF], elevated baseline heart rate and lower systolic blood pressure). Use of the Impella CP, intraprocedural complications, periprocedural complications and in-hospital mortality were all more common amongst the prolonged MCS group. Prolonged MCS was associated with increased rates of major adverse cardiovascular and cerebrovascular events, cardiovascular death, and all-cause mortality at 90-day follow-up.

CONCLUSIONS

Patients receiving prolonged MCS after Impella-supported HR-PCI presented with more ACS, reduced EF and less favourable haemodynamics. Additionally, they were more likely to experience intraprocedural and periprocedural complications as well as increased in-hospital and post-discharge mortality.

Impact of in-Hospital Left Ventricular Ejection Fraction Recovery on Long-Term Outcomes in Patients Who Underwent Impella Support for HR PCI or Cardiogenic Shock: A Sub-Analysis from the IMP-IT Registry

(1) Background: Percutaneous left ventricle assist devices (pLVADs) demonstrated an improvement in mid-term clinical outcomes in selected patients with severely depressed left ventricular ejection fraction (LVEF) undergoing percutaneous coronary interventions. However, the prognostic impact of in-hospital LVEF recovery is unclear. Accordingly, the present sub-analysis aims to evaluate the impact of LVEF recovery in both cardiogenic shock (CS) and high-risk percutaneous coronary intervention (HR PCI) supported with pLVADs in the IMP-IT registry. (2) Methods: A total of 279 patients (116 patients in CS and 163 patients in HR PCI) treated with Impella 2.5 or CP in the IMP-IT registry were included in this analysis, after excluding those who died while in the hospital or with missing data on LVEF recovery. The primary study objective was a composite of all-cause death, rehospitalisation for heart failure, left ventricle assist device (LVAD) implantation, or heart transplantation (HT), overall referred to as the major adverse cardiac events (MACE) at 1 year. The study aimed to evaluate the impact of in-hospital LVEF recovery on the primary study objective in patients treated with Impella for HR PCI and CS, respectively. (3) Results: The mean in-hospital change in LVEF was 10 ± 1% (p < 0.001) in the CS cohort and 3 ± 7% (p < 0.001) in the HR PCI group, achieved by 44% and 40% of patients, respectively. In the CS group, patients with less than 10% in-hospital LVEF recovery experienced higher rates of MACE at 1 year of follow-up (FU) (51% vs. 21%, HR 3.8, CI 1.7-8.4, p < 0.01). After multivariate analysis, LVEF recovery was the main independent protective factor for MACE at FU (HR 0.23, CI 0.08-0.64, p = 0.02). In the HR PCI group, LVEF recovery (>3%) was not associated with lower MACE at multivariable analysis (HR 0.73, CI 0.31-1.72, p = 0.17). Conversely, the completeness of revascularisation was found to be a protective factor for MACE (HR 0.11, CI 0.02-0.62, p = 0.02) (4) Conclusions: Significant LVEF recovery was associated with improved outcomes in CS patients treated with PCI during mechanical circulatory support with Impella, whereas complete revascularisation showed a significant clinical relevance in HR PCI.

Microaxial circulatory support for percutaneous coronary intervention: A systematic review and meta-analysis

BACKGROUND

Microaxial circulatory support devices have been used to support patients treated with percutaneous coronary intervention (PCI) for acute myocardial infarction complicated by cardiogenic shock (AMICS). The purpose of this systematic review and meta-analysis was to pool and analyze the existing evidence on the baseline characteristics, periprocedural data, and outcomes of microaxial support before and after PCI in AMICS.

METHODS

An electronic database search was performed to identify all cohort studies on Impella and PCI for cardiogenic shock in the English language. A total of five articles comprising 543 patients were included. These patients received microaxial support either before (pre-PCI) or after (post-PCI) undergoing PCI. Comparative analyses were done between both groups.

RESULTS

The mean patient age was 66 years [95% Confidence Interval (58-74)], and 22% (89/396) of patients were female. ST-elevation myocardial infarctions (MI) comprised 64% (44-80) of MIs and 50% (44-56) of MIs involved the left anterior descending artery. The mean number of diseased vessels was 2.21 (1.62-2.80). The mean left ventricular ejection fraction was 31% (23.4-38.6). The mean arterial pressure was 66.3 mm Hg (54.1-78.5). Mean serum lactate [6.1 mmol/L (3.3-8.9)] and serum creatinine [1.4 mg/dl (1.0-1.7)] were similar between groups. 30-day mortality was lower in the pre-PCI group [41% (34%-49%)] compared to the post-PCI group [61% (42%-77%), p < 0.01]. Pooled Kaplan-Meier analysis showed better early survival in the pre-PCI group (p < 0.001).

CONCLUSION

Patients presenting with AMICS were similar at baseline in both pre-PCI and post-PCI groups. Nevertheless, pre-PCI group showed better early survival compared to post-PCI group.

Impella RP for Patients with Acute Right Ventricular Failure and Cardiogenic Shock: A Subanalysis from the IMP-IT Registry

The use of percutaneous right ventricular assist devices (pRVADs) to support patients with right ventricular (RV)-predominant cardiogenic shock (CS) refractory to optimal medical therapy is increasing progressively, and the Impella RP is the first FDA-approved pRVAD in such a clinical scenario. The aim of the present study is to report the outcomes of patients treated with Impella RP in the IMP-IT (IMPella Mechanical Circulatory Support Device in Italy) registry, a multicenter registry that evaluated the trends in use and clinical outcomes of the Impella in the setting of CS and high-risk percutaneous coronary intervention in Italy. A total of 15 patients who received Impella RP were enrolled. In 40% of the patients, the main cause was ST-segment elevation myocardial infarction. A total of 40% of patients required biventricular support with a left Impella. Device-related complications were reported in 46.7% of patients. Overall, the in-hospital mortality was 46.7%, whereas the one-year mortality was 53.3%. The composite rate of all-cause death, heart failure (HF) hospitalization, left ventricular assist device (LVAD) and heart transplant at one year was 60%. The Impella RP has favorable survival outcomes in RV-predominant cardiogenic shock. However, the device-related complications are frequent and should be carefully weighed when considering escalation to Impella RP.

When to Achieve Complete Revascularization in Infarct-Related Cardiogenic Shock

Acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) is a life-threatening condition frequently encountered in patients with multivessel coronary artery disease (CAD). Despite prompt revascularization, in particular, percutaneous coronary intervention (PCI), and therapeutic and technological advances, the mortality rate for patients with CS related to AMI remains unacceptably high. Differently form a hemodynamically stable setting, a culprit lesion-only (CLO) revascularization strategy is currently suggested for AMI–CS patients, based on the results of recent randomized evidence burdened by several limitations and conflicting results from non-randomized studies. Furthermore, mechanical circulatory support (MCS) devices have emerged as a key therapeutic option in CS, especially in the case of their early implantation without delaying revascularization and before irreversible organ damage has occurred. We provide an in-depth review of the current evidence on optimal revascularization strategies of multivessel CAD in infarct-related CS, assessing the role of different types of MCS devices and highlighting the importance of shock teams and medical care system networks to effectively impact on clinical outcomes.

Mechanical circulatory support in cardiogenic shock: a critical appraisal

INTRODUCTION

Acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) is a life-threatening condition frequently encounter in patients with multivessel coronary artery disease (MVD).

AREAS COVERED

Despite prompt revascularization, in particular percutaneous coronary intervention (PCI), and therapeutic and technological advances, the mortality rate for CS related to AMI remains high. Differently from hemodynamically stable setting, a culprit lesion-only (CLO) revascularization strategy is currently suggested in AMI-CS patients, based on the results of a recent randomized evidence burdened by several limitations and conflicting results from non-randomized studies. Furthermore, mechanical circulatory support (MCS) devices have raised as a key therapeutic option in CS, especially in case of an early implantation without delaying revascularization and before irreversible organ damage has occurred. We provide an in-depth review of current evidences on optimal revascularization strategies of multivessel CAD in infarct-related CS, assessing the role of MCS devices, and highlighting the importance of shock teams and medical care system networks to effectively impact on clinical outcomes.

EXPERT OPINION

Emerging observational experience suggested that an early implantation of MCS (prior to PCI), the performance of an extensive revascularization and the implementation of shock teams and networks are key factors for improving clinical outcomes.

Impella to Treat Acute Myocardial Infarct-Related Cardiogenic Shock

Acute myocardial infarction complicated by cardiogenic shock (AMICS), is characterized by critically low cardiac output and decreased myocardial contractility. In this situation, a treatment that unloads the myocardium and restores CO without increasing the myocardial oxygen demand is theoretically appealing. Axial flow pumps offer hemodynamic support without increasing myocardial oxygen consumption. Consequently, the use of axial flow pumps, especially the Impella devices, is increasing. It is likely that the SCAI C patient with predominantly left ventricular failure and without prolonged cardiac arrest is the best candidate for these devices. Registry data suggest that pre-PCI Impella may be advantageous to post-PCI placement. However, several gaps in knowledge exist regarding optimal patient selection, futility criteria, timing, weaning and escalation strategy, and until data from adequately sized randomized trials are available, immediate individual evaluation for mechanical circulatory support by a shock team is warranted when a patient is diagnosed with AMICS.

Timing of mechanical circulatory support during primary angioplasty in acute myocardial infarction and cardiogenic shock: Systematic review and meta-analysis

OBJECTIVES

We aim to define whether the timing of microaxial left ventricular assist device (IMLVAD) implantation might impact on mortality in acute myocardial infarction (AMI) cardiogenic shock (CS) patients who underwent primary percutaneous coronary intervention (PPCI).

BACKGROUND

Despite the widespread use of PPCI, mortality in patients with AMI and CS remains high. Mechanical circulatory support is a promising bridge to recovery strategy, but evidence on its benefit is still inconclusive and the optimal timing of its utilization remains poorly explored.

METHODS

We compared clinical outcomes of upstream IMLVAD use before PPCI versus bailout use after PPCI in patients with AMI CS. A systematic review and meta-analysis of studies comparing the two strategies were performed. Effect size was reported as odds ratio (OR) using bailout as reference group and a random effect model was used. Study-level risk estimates were pooled through the generic inverse variance method (random effect model).

RESULTS

A total of 11 observational studies were identified, including a pooled population of 6759 AMI-CS patients. Compared with a bailout approach, upstream IMLVAD was associated with significant reduction of 30-day (OR = 0.65; 95% confidence interval [CI] = 0.51-0.82; I²  = 43%, adjusted OR = 0.54; 95% CI = 0.37-0.59; I²  = 3%, test for subgroup difference p = 0.30), 6-month (OR = 0.51; 95% CI = 0.27-0.96; I²  = 66%), and 1-year (OR = 0.56; 95% CI = 0.39-0.79; I²  = 0%) all-cause mortality. Incidence of access-related bleeding, acute limb ischemia and transfusion outcomes were similar between the two strategies.

CONCLUSION

In patients with AMI-CS undergoing PPCI, upstream IMLVAD was associated with reduced early and midterm all-cause mortality when compared with a bailout strategy.