Mechanical assist devices for acute cardiogenic shock

Myocardial Infarction-Associated Shock: A Comprehensive Analysis of Phenotypes, SCAI Classification, and Outcome Assessment

Background and Objectives: In-hospital mortality associated with myocardial infarction complicated by cardiogenic shock (MI-CS) remains critically high. A particularly challenging form, mixed shock (MS), combines features of cardiogenic shock (CS) with distributive elements such as vasodilation and reduced vascular resistance. MS is associated with elevated mortality rates and presents unique diagnostic and therapeutic challenges. This study aimed to analyze the clinical, historical, instrumental, and laboratory characteristics of the primary phenotypes of MI-CS, stratified according to the Society for Cardiovascular Angiography and Interventions (SCAI) shock severity scale. Materials and Methods: In this single-center, retrospective observational study, we reviewed the medical records of 1289 patients admitted to the emergency cardiology department from 1 January to 12 December 2020. Among them, 117 patients were identified as having MI-CS and were divided into two groups: MS (n = 48) and isolated CS (n = 69). The data were analyzed using the SCAI shock classification. Logistic regression analysis was employed to identify predictors of mortality and improved survival outcomes. Results: Patients with MS were older (80 years [71.0; 83.0] vs. 73 years [64.0; 81.0], p = 0.035). The overall mortality rate was significantly higher in the MS group (68% vs. 53%, RR = 1.438, 95% CI: 1.041-1.986, p = 0.03). Logistic regression identified mechanical ventilation (OR = 8.33, 95% CI: 2.54-22.80, p = 0.012), elevated lactate levels (OR = 1.20, 95% CI: 1.02-1.41, p = 0.026), and cardiopulmonary resuscitation (CPR) (OR = 7.97, 95% CI: 2.51-24.40, p < 0.0001) as independent predictors of mortality. Conversely, the use of an intra-aortic balloon pump (IABP) (OR = 0.22, 95% CI: 0.06-0.80, p = 0.021) and a higher body mass index (BMI) (OR = 0.91, 95% CI: 0.84-0.99, p = 0.038) were associated with reduced mortality risk. Conclusions: MS in the context of MI-CS represents a distinct clinical phenotype with specific hemodynamic features and significantly worsened outcomes. The identification of mortality predictors, such as mechanical ventilation, elevated lactate levels, and CPR, alongside protective factors like IABP use and a higher BMI, underscores the importance of early and tailored therapeutic interventions. These findings highlight the need for further studies to refine treatment protocols and improve outcomes in this high-risk population.

Resource Utilization and Costs Associated With Cardiogenic Shock Complicating Myocardial Infarction: A Population-Based Cohort Study

Background

Cardiogenic shock due to acute myocardial infarction (AMI-CS) is associated with significant short- and long-term morbidity and mortality. Despite this, little is known about associated cost.

Objectives

The purpose of this study was to evaluate the health care costs and resource use associated with AMI-CS using administrative data from the province of Ontario, Canada.

Methods

This was a retrospective cohort study of adult patients with AMI-CS from April 2009 to March 2019. One-year costs following index admission were reported at an individual level. We used generalized linear models to identify factors associated with increased cost. We stratified patients by revascularization strategy to compare cost in each group and examined total cost at a patient level per individual fiscal year.

Results

We included 9,789 consecutive patients with AMI-CS across 135 centers in Ontario (mean age 70.5 years; 67.7% male). Mortality in-hospital was 30.2%, and mortality at 2 years was 45.9%. The median inpatient cost per patient was $23,912 (IQR: $12,234-$41,833) with a median total 1-year cost of $37,913 (IQR: $20,113-$66,582). The median 1-year cost was $17,730 (IQR: $9,323-$38,379) for those who died in hospital, and $45,713 (IQR: $29,688-$77,683) for those surviving to discharge, with $12,719 (IQR: $4,262-$35,275) occurring after discharge. Patients who received coronary artery bypass grafting incurred the highest cost among revascularization groups. No significant differences were observed in cost per fiscal year from 2009 to 2019.

Conclusions

AMI-CS is associated with significant health care costs, both during the index hospitalization and following discharge. To optimize cost-effectiveness, future therapies should aim to reduce disability in addition to improving mortality.

Mechanical Assist Device-Assisted Percutaneous Coronary Intervention: The Use of Impella Versus Extracorporeal Membrane Oxygenation as an Emerging Frontier in Revascularization in Cardiogenic Shock

The extracorporeal membrane oxygenation (ECMO) procedure aids in the provision of prolonged cardiopulmonary support, whereas the Impella device (Abiomed, Danvers, MA) is a ventricular assist device that maintains circulation by pumping blood into the aorta from the left ventricle. Blood is circulated in parallel with the heart by Impella. It draws blood straight into the aorta from the left ventricle, hence preserving the physiological flow. ECMO bypasses the left atrium and the left ventricle, and the end consequence is a non-physiological flow. In this article, we conducted a detailed analysis of various publications in the literature and examined various modalities pertaining to the use of ECMO and Impella for cardiogenic shocks, such as efficacy, clinical outcomes, cost-effectiveness, device-related complications, and limitations. The Impella completely unloads the left ventricle, thereby significantly reducing the effort of the heart. Comparatively, ECMO only stabilizes a patient with cardiogenic shock for a short stretch of time and does not lessen the efforts of the left ventricle ("unload" it). In the acute setting, both devices reduced left ventricular end-diastolic pressure and provided adequate hemodynamic support. By comparing patients on Impella to those receiving ECMO, it was found that patients on Impella were associated with better clinical results, quicker recovery, limited complications, and reduced healthcare costs; however, there is a lack of conclusive studies performed demonstrating the reduction in long-term mortality rates. Considering the effectiveness of given modalities and taking into account the various studies described in the literature, Impella has reported better clinical outcomes although more clinical trials are needed for establishing the effectiveness of these interventional approaches in revascularization in cardiogenic shock.

Inotropes, vasopressors, and mechanical circulatory support for treatment of cardiogenic shock complicating myocardial infarction: a systematic review and network meta-analysis

PURPOSE

To compare the relative efficacy of supportive therapies (inotropes, vasopressors, and mechanical circulatory support [MCS]) for adult patients with cardiogenic shock complicating acute myocardial infarction.

SOURCE

We conducted a systematic review and network meta-analysis and searched six databases from inception to December 2021 for randomized clinical trials (RCTs). We evaluated inotropes, vasopressors, and MCS in separate networks. Two reviewers performed screening, full-text review, and extraction. We used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework to rate the certainty in findings. The critical outcome of interest was 30-day all-cause mortality.

PRINCIPAL FINDINGS

We included 17 RCTs. Among inotropes (seven RCTs, 1,145 patients), levosimendan probably reduces mortality compared with placebo (odds ratio [OR], 0.53; 95% confidence interval [CI], 0.33 to 0.87; moderate certainty), but primarily in lower severity shock. Milrinone (OR, 0.52; 95% CI, 0.19 to 1.39; low certainty) and dobutamine (OR, 0.67, 95% CI, 0.30 to 1.49; low certainty) may have no effect on mortality compared with placebo. With regard to MCS (eight RCTs, 856 patients), there may be no effect on mortality with an intra-aortic balloon pump (IABP) (OR, 0.94; 95% CI, 0.69 to 1.28; low certainty) or percutaneous MCS (pMCS) (OR, 0.96; 95% CI, 0.47 to 1.98; low certainty), compared with a strategy involving no MCS. Intra-aortic balloon pump use was associated with less major bleeding compared with pMCS. We found only two RCTs evaluating vasopressors, yielding insufficient data for meta-analysis.

CONCLUSION

The results of this systematic review and network meta-analysis indicate that levosimendan reduces mortality compared with placebo among patients with low severity cardiogenic shock. Intra-aortic balloon pump and pMCS had no effect on mortality compared with a strategy of no MCS, but pMCS was associated with higher rates of major bleeding.

STUDY REGISTRATION

Center for Open Science ( https://osf.io/ky2gr ); registered 10 November 2020.