Mechanical Circulatory Support Devices in Acute Myocardial Infarction-Cardiogenic Shock: Current Studies and Future Directions

Temporary mechanical circulatory support utilization and outcomes in cardiogenic shock phenotypes: A comparative analysis of heart failure and acute myocardial infarction

INTRODUCTION

Cardiogenic shock (CS) is marked by substantial morbidity and mortality. The two major CS etiologies include heart failure (HF) and acute myocardial infarction (AMI). The utilization trends of mechanical circulatory support (MCS) and their clinical outcomes are not well described.

METHODS

This study compares the rates of MCS utilization, factors associated with utilization, and clinical outcomes in patients who present with HF-CS and AMI-CS, using 2016-2020 National Inpatient Sample data.

RESULTS

The study included 329,280 patients, comprising 204,660 cases of AMI-CS and 124,620 of HF-CS. MCS utilization increased over the study period with variable degree among devices, and CS-phenotype. AMI-CS had higher intraaortic balloon pump (32.4 % vs. 8.9 %), extracorporeal membrane oxygenation (2.8 % vs. 2.4 %), and percutaneous ventricular assist device use (14.5 % vs. 8.1 %) compared to HF-CS (p < 0.01). Factors linked to lower MCS use were female sex, age over 60 years, Black race, atrial fibrillation, chronic obstructive lung disease, diabetes mellitus, cirrhosis, previous stroke, or myocardial infarction. After adjusting for various factors, patients with HF-CS vs. AMI-CS had significantly fewer adverse outcomes, including inpatient death, stroke, tracheostomy, mechanical ventilation, and blood transfusion. However, HF-CS had higher odds of acute renal failure requiring dialysis. AMI-CS was associated with shorter hospital stays (8.8 vs. 15.0 days, p < 0.001), lower charges ($251,580 vs. $294,792, p < 0.001), and were less likely to discharge home.

CONCLUSION

Despite the evolving trends in MCS utilization over time, CS patients still face high morbidity and mortality rates. The underlying shock etiology has a substantial impact on outcomes, with AMI cases demonstrating worse complications. This highlights the need for a standardized approach that also takes into consideration etiology, patient-specific factors, care availability, and equitable access.

US trends of in-hospital morbidity and mortality for acute myocardial infarctions complicated by cardiogenic shock

BACKGROUND

There is limited real-world data highlighting recent temporal in-hospital morbidity and mortality trends for cases of acute myocardial infarction complicated by cardiogenic shock. The role of mechanical circulatory support within this patient population remains unclear.

METHODS

The US National Inpatient Sample database was sampled from 2011 to 2018 identifying 206,396 hospitalizations with a primary admission diagnosis of ST- or Non-ST elevation myocardial infarction complicated by cardiogenic shock. The primary outcomes included trends of all-cause in-hospital mortality, mechanical circulatory support use, and sex-specific trends for acute myocardial infarction complicated by cardiogenic shock (AMI-CS) over the study period.

RESULTS

The annual number of AMI-CS hospitalizations increased from 22,851 in 2011 to 30,015 in 2018 and in-hospital mortality trends remained similar (42.9 % to 43.7 %, ptrend < 0.001). The proportion of patients receiving any temporary MCS device decreased (46.4 % to 44.4 %). The use of intra-aortic balloon pump (IABP) decreased (44.9 % to 32.9 %) and the use of any other non-IABP MCS device increased (2.5 % to 15.6 %), ptrend<0.001. Sex-specific mortality indicate female in-hospital mortality remained similar (50.3 % to 51 %, ptrend<0.001), but higher than male in-hospital mortality, which increased non-significantly (38.8 % to 40.2 %, ptrend = 0.372).

CONCLUSIONS

From 2011 to 2018, hospitalizations for AMI-CS patients have increased in number. However, there has been no recent appreciable change in AMI-CS mortality despite a changing treatment landscape with decreasing use of IABPs and increasing use of non-IABP MCS devices. Further research is necessary to examine the appropriate use of MCS devices within this population.

The Management of Cardiogenic Shock From Diagnosis to Devices: A Narrative Review

Cardiogenic shock (CS) is a heterogenous syndrome broadly characterized by inadequate cardiac output leading to tissue hypoperfusion and multisystem organ dysfunction that carries an ongoing high mortality burden. The management of CS has advanced rapidly, especially with the incorporation of temporary mechanical circulatory support (tMCS) devices. A thorough understanding of how to approach a patient with CS and to select appropriate monitoring and treatment paradigms is essential in modern ICUs. Timely characterization of CS severity and hemodynamics is necessary to optimize outcomes, and this may be performed best by multidisciplinary shock-focused teams. In this article, we provide a review of CS aimed to inform both the cardiology-trained and non-cardiology-trained intensivist provider. We briefly describe the causes, pathophysiologic features, diagnosis, and severity staging of CS, focusing on gathering key information that is necessary for making management decisions. We go on to provide a more detailed review of CS management principles and practical applications, with a focus on tMCS. Medical management focuses on appropriate medication therapy to optimize perfusion-by enhancing contractility and minimizing afterload-and to facilitate decongestion. For more severe CS, or for patients with decompensating hemodynamic status despite medical therapy, initiation of the appropriate tMCS increasingly is common. We discuss the most common devices currently used for patients with CS-phenotyping patients as having left ventricular failure, right ventricular failure, or biventricular failure-and highlight key available data and particular points of consideration that inform tMCS device selection. Finally, we highlight core components of sedation and respiratory failure management for patients with CS.

Contemporary approach to cardiogenic shock care: a state-of-the-art review

Cardiogenic shock (CS) is a time-sensitive and hemodynamically complex syndrome with a broad spectrum of etiologies and clinical presentations. Despite contemporary therapies, CS continues to maintain high morbidity and mortality ranging from 35 to 50%. More recently, burgeoning observational research in this field aimed at enhancing the early recognition and characterization of the shock state through standardized team-based protocols, comprehensive hemodynamic profiling, and tailored and selective utilization of temporary mechanical circulatory support devices has been associated with improved outcomes. In this narrative review, we discuss the pathophysiology of CS, novel phenotypes, evolving definitions and staging systems, currently available pharmacologic and device-based therapies, standardized, team-based management protocols, and regionalized systems-of-care aimed at improving shock outcomes. We also explore opportunities for fertile investigation through randomized and non-randomized studies to address the prevailing knowledge gaps that will be critical to improving long-term outcomes.

Treatment of Acute Myocardial Infarction and Cardiogenic Shock: Outcomes of the RECOVER III Postapproval Study by Society of Cardiovascular Angiography and Interventions Shock Stage

BACKGROUND

The Society for Cardiovascular Angiography and Interventions proposed a staging system (A-E) to predict prognosis in cardiogenic shock. Herein, we report clinical outcomes of the RECOVER III study for the first time, according to Society for Cardiovascular Angiography and Interventions shock classification.

METHODS AND RESULTS

The RECOVER III study is an observational, prospective, multicenter, single-arm, postapproval study of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support. Patients enrolled in the RECOVER III study were assigned a baseline Society for Cardiovascular Angiography and Interventions shock stage. Staging was then repeated within 24 hours after initiation of Impella. Kaplan-Meier survival curve analyses were conducted to assess survival across Society for Cardiovascular Angiography and Interventions shock stages at both time points. At baseline assessment, 16.5%, 11.4%, and 72.2% were classified as stage C, D, and E, respectively. At ≤24-hour assessment, 26.4%, 33.2%, and 40.0% were classified as stage C, D, and E, respectively. Thirty-day survival among patients with stage C, D, and E shock at baseline was 59.7%, 56.5%, and 42.9%, respectively (P=0.003). Survival among patients with stage C, D, and E shock at ≤24 hours was 65.7%, 52.1%, and 29.5%, respectively (P<0.001). After multivariable analysis of impact of shock stage classifications at baseline and ≤24 hours, only stage E classification at ≤24 hours was a significant predictor of mortality (odds ratio, 4.8; P<0.001).

CONCLUSIONS

In a real-world cohort of patients with acute myocardial infarction with cardiogenic shock undergoing percutaneous coronary intervention with Impella support, only stage E classification at ≤24 hours was significantly predictive of mortality, suggesting that response to therapy may be more important than clinical severity of shock at presentation.

Glimpse into the future

Randomized studies attempting to prove benefit of mechanical circulatory support in cardiogenic shock have failed to reduce the risk of death. Further, both registry and randomized data suggest increased rates of serious complications associated with these devices. This last review in the supplement discusses current evidence and provides a perspective on how the scientific community could advance cardiogenic shock research focused on mechanical circulatory support.

Network meta-analysis of temporary mechanical circulatory support in acute myocardial infarction cardiogenic shock

We performed a network meta-analysis of 11 published randomized clinical trials examining the use of temporary mechanical circulatory support (MCS) devices in adults with acute myocardial infarction cardiogenic shock, including 1,053 total patients with an observed in-hospital or 30-day mortality of 40.4%. None of the temporary MCS devices was associated with lower in-hospital or 30-day mortality compared with initial medical therapy or any other MCS device, either individually or in combination. These data do not support the routine use of temporary MCS devices for the purpose of reducing short-term mortality in unselected patients with acute myocardial infarction cardiogenic shock.