Predictors of survival and ability to wean from short-term mechanical circulatory support device following acute myocardial infarction complicated by cardiogenic shock

Outcomes following successful decannulation from extracorporeal life support for cardiogenic shock

OBJECTIVE

Although extracorporeal life support (ECLS) has increasingly been used for the treatment of patients with cardiogenic shock (CS), the outcomes of those successfully weaned from support remain poorly defined.

METHODS

Of 510 venoarterial ECLS CS patients at our institution between January 2015 and December 2020, 249 were decannulated and survived for 30 days or until discharge (ie, successfully weaned). Factors associated with survival to discharge were assessed and 1-year survival was described.

RESULTS

Of 510 eligible CS ECLS patients, 249 (48.8%) were successfully decannulated, 227 (44.5%) died during/following ECLS, and 34 (6.7%) were bridged to heart transplantation or a ventricular assist device. Patients with a primary graft dysfunction etiology of CS had a greater chance of successful decannulation (odds ratio [OR], 3.088; 95% CI, 1.1-8.671; P = .0323), whereas patients with ECLS during cardiopulmonary resuscitation had a reduced chance of successful decannulation (OR, 0.354; 95% CI, 0.17-0.735; P = .0054). Of successfully decannulated patients, 218 (87.6%) survived to hospital discharge and 31 (12.4%) died in the hospital. Acute myocardial infarction etiology (OR, 4.751; 95% CI, 1.623-13.902; P = .0044), preexisting chronic kidney disease (OR, 3.422; 95% CI, 1.374-8.52; P = .0082), and initiation of continuous renal replacement therapies (OR, 3.188; 95% CI, 1.291-7.871; P = .012) were significantly associated with in-hospital mortality despite successful decannulation. One-year survival in successfully decannulated patients surviving to hospital discharge was 95.0% and comparable to 1-year survival in patients who received a heart transplant or ventricular assist device.

CONCLUSIONS

Successful decannulation can be achieved in a significant proportion of patients treated with ECLS for CS but does not guarantee survival to hospital discharge. However, 1-year survival of hospital survivors remains high and is comparable to patients bridged to transplant or a ventricular assist device.

Long-term outcomes of patients bridged to recovery with venoarterial extracorporeal life support

OBJECTIVE

Our study examines the long-term outcomes of patients discharged from the hospital without heart replacement therapy (HRT) after recovery from cardiogenic shock using venoarterial extracorporeal life support (VA-ECLS).

METHODS

We retrospectively reviewed 615 cardiogenic shock patients who recovered from VA-ECLS at our institution between January 2015 and July 2021. Of those, 166 patients (27.0%) who recovered from VA-ECLS without HRT were included in this study. Baseline characteristics, discharge labs, vitals, electrocardiograms and echocardiograms were assessed. Patients were contacted to determine vital status. The primary outcome was post-discharge mortality.

RESULTS

Of 166 patients, 158 patients (95.2%) had post-discharge follow-up, with a median time of follow-up of 2 years (IQR: [1 year, 4 years]). At discharge, the median ejection fraction (EF) was 52.5% (IQR: [32.5, 57.5]). At discharge, 92 patients (56%) were prescribed β-blockers, 28 (17%) were prescribed an ACE inhibitor, ARB or ARNI, and 50 (30%) were prescribed loop diuretics. Kaplan-Meier analysis showed a 1-year survival rate of 85.6% (95% CI: [80.1%, 91.2%]) and a 5-year survival rate of 60.6% (95% CI: [49.9%, 71.3%]). A Cox regression model demonstrated that a history of congestive heart failure (CHF) was strongly predictive of increased mortality hazard (HR = 1.929; p = 0.036), while neither discharge EF nor etiology of VA-ECLS were associated with increased post-discharge mortality.

CONCLUSIONS

Patients discharged from the hospital after full myocardial recovery from VA-ECLS support without HRT should have close outpatient follow-up due to the risk of recurrent heart failure and increased mortality in these patients.

Incremental cost-effectiveness of extracorporeal membranous oxygenation as a bridge to cardiac transplant or left ventricular assist device placement in patients with refractory cardiogenic shock

Objective

Emerging literature has described using venoarterial extracorporeal membranous oxygenation (ECMO) as a bridge to transplant or left ventricular assist device (LVAD) placement. We sought to identify the incremental cost-effectiveness ratio (ICER) of ECMO used as a bridge to cardiac transplant or LVAD.

Methods

Patients with refractory cardiogenic shock who received venoarterial ECMO and were bridged to either cardiac transplant (n = 7) or a HeartMate 3 LVAD (n = 6) placement were included. Markov modeling was used, comparing ECMO bridging with non–ECMO-bridged patients. Cohorts entered the model alive and at every 1-year cycle, were exposed to risk of death, and ran forward for 20 years after transplant or LVAD.

Results

Patients bridged with ECMO to cardiac transplant were stratified as group 1 whereas those bridged with ECMO to LVAD were stratified as group 2. The average ECMO run was 3 days in group 1 versus 11 days in group 2. Among group 1 patients, the ICER was $246,629 but was paired with a longer life expectancy. The ICER of group 2 patients was –$107,088 and was not paired with a longer life expectancy. The average inpatient cost for group 1 was found to be $636,023 versus $769,471 for group 2 patients. The average inpatient costs for patients not bridged to ECMO who received cardiac transplant or LVAD was $538,928 and $325,242, respectively.

Conclusions

Using ECMO to bridge to transplant or LVAD placement is not cost effective. However, patients bridged to transplant are paired with longer life expectancy in contrast to patients bridged to LVAD.

Hysteretic device characteristics indicate cardiac contractile state for guiding mechanical circulatory support device use

Background

Acute heart failure and cardiogenic shock remain highly morbid conditions despite prompt medical therapy in critical care settings. Mechanical circulatory support (MCS) is a promising therapy for these patients, yet remains managed with open-loop control. Continuous measure of cardiac function would support and optimize MCS deployment and weaning. The nature of indwelling MCS provides a platform for attaining this information. This study investigates how hysteresis modeling derived from MCS device signals can be used to assess contractility changes to provide continuous indication of changing cardiac state. Load-dependent MCS devices vary their operation with cardiac state to yield a device–heart hysteretic interaction. Predicting and examining this hysteric relation provides insight into cardiac state and can be separated by cardiac cycle phases. Here, we demonstrate this by predicting hysteresis and using the systolic portion of the hysteresis loop to estimate changes in native contractility. This study quantified this measurement as the enclosed area of the systolic portion of the hysteresis loop and correlated it with other widely accepted contractility metrics in animal studies (n = 4) using acute interventions that alter inotropy, including a heart failure model. Clinical validation was performed in patients (n = 8) undergoing Impella support.

Results

Hysteresis is well estimated from device signals alone (r = 0.92, limits of agreement: − 0.18 to 0.18). Quantified systolic area was well correlated in animal studies with end-systolic pressure–volume relationship (r = 0.84), preload recruitable stroke work index (r = 0.77), and maximum slope of left ventricular pressure (dP/dt_max) (r = 0.95) across a range of inotropic conditions. Comparable results were seen in patients with dP/dt_max (r = 0.88). Diagnostic capability from ROC analysis yielded AUC measurements of 0.92 and 0.90 in animal and patients, respectively.

Conclusions

Mechanical circulatory support hysteretic behavior can be well modeled using device signals and used to estimate contractility changes. Contractility estimate is correlated with other accepted metrics, captures temporal trends that elucidate changing cardiac state, and is able to accurately indicate changes in inotropy. Inherently available during MCS deployment, this measure will guide titration and inform need for further intervention.

A systematic approach to weaning from extracorporeal membrane oxygenation in patients with refractory cardiac failure

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is commonly used to provide haemodynamic support for patients with severe cardiac failure. However, timing ECMO weaning remains challenging. We aimed to examine if an integrative weaning approach based on predefined haemodynamic, respiratory and echocardiographic criteria is associated with successful weaning.

METHODS

All patients weaned from ECMO between April 2017 and April 2019 at Aarhus University Hospital, Denmark, were consecutively enrolled. Predefined haemodynamic, respiratory and echocardiographic criteria were assessed before and during ECMO flow reduction. A weaning attempt was commenced in haemodynamic stable patients and patients remaining stable at minimal flow were weaned from ECMO. Comparisons were made between patients who met the criteria for weaning at first attempt and patients who did not meet these criteria. Patients completing a full weaning attempt with no further need for mechanical support within 24 h were defined as successfully weaned.

RESULTS

A total of 38 patients were included in the study, of whom 26 (68%) patients met the criteria for weaning. Among these patients, 25 (96%) could be successfully weaned. Successfully weaned patients were younger and had less need for inotropic support and ECMO duration was shorter. Fulfilling the weaning criteria was associated with successful weaning and both favourable 30-d survival and survival to discharge.

CONCLUSION

An integrative weaning approach based on haemodynamic, respiratory and echocardiographic criteria may strengthen the clinical decision process in predicting successful weaning in patients receiving ECMO for refractory cardiac failure.

The mechanical support of cardiogenic shock

PURPOSE OF REVIEW

Cardiogenic shock (CS) therapy involving catecholamines, inotropes, fluids and revascularization is often insufficient, and short-term mortality remains 50%. Different treatment algorithms and mechanical circulatory support devices (MCS) have been increasingly used in the treatment of CS. Coronavirus disease 2019 (COVID-19) pandemic is a major challenge faced by intensive care medicine providers inevitably influencing also CS management.

RECENT FINDINGS

There is a lack of prospective data as well as international consensus regarding CS classification, patient risk stratification, and MCS use. Veno-arterial extracorporeal membrane oxygenation is considered the first line MCS in refractory CS and Impella the MCS of choice for the left ventricle unloading. Several ongoing randomized trials will provide much-needed evidence for MCS use in the coming years. COVID-19 infection is associated with several cardiovascular disorders complicated by CS and more data regarding the prevalence and mortality of CS during COVID-19 infection are needed.

SUMMARY

This review summarizes current trends in the use of MCS in CS and discusses differences in CS management during the COVID-19 pandemic. Careful patient selection, early MCS initiation, and comprehensive intensive care by experienced team is key to successful outcome in patients with refractory CS.

ECMO in Cardiac Arrest: A Narrative Review of the Literature

Cardiac arrest (CA) is a frequent cause of death and a major public health issue. To date, conventional cardiopulmonary resuscitation (CPR) is the only efficient method of resuscitation available that positively impacts prognosis. Extracorporeal membrane oxygenation (ECMO) is a complex and costly technique that requires technical expertise. It is not considered standard of care in all hospitals and should be applied only in high-volume facilities. ECMO combined with CPR is known as ECPR (extracorporeal cardiopulmonary resuscitation) and permits hemodynamic and respiratory stabilization of patients with CA refractory to conventional CPR. This technique allows the parallel treatment of the underlying etiology of CA while maintaining organ perfusion. However, current evidence does not support the routine use of ECPR in all patients with refractory CA. Therefore, an appropriate selection of patients who may benefit from this procedure is key. Reducing the duration of low blood flow by means of performing high-quality CPR and promoting access to ECPR, may improve the survival rate of the patients presenting with refractory CA. Indeed, patients who benefit from ECPR seem to carry better neurological outcomes. The aim of this present narrative review is to present the most recent literature available on ECPR and to clarify its potential therapeutic role, as well as to provide an in-depth explanation of equipment and its set up, the patient selection process, and the patient management post-ECPR.

Temporary circulatory support for cardiogenic shock

Cardiogenic shock can occur due to acute ischaemic or non-ischaemic cardiac events, or from progression of long-standing underlying heart disease. When addressing the cause of underlying disease, the management of cardiogenic shock consists of vasopressors and inotropes; however, these agents can increase myocardial oxygen consumption, impair tissue perfusion, and are frequently ineffective. An alternative approach is to temporarily augment cardiac output using mechanical devices. The use of these devices-known as temporary circulatory support systems-has increased substantially in recent years, despite being expensive, resource intensive, associated with major complications, and lacking high-quality evidence to support their use. This Review summarises the physiological basis underlying the use of temporary circulatory support for cardiogenic shock, reviews the evidence informing indications and contraindications, addresses ethical considerations, and highlights the need for further research.

Predictors of Survival for Patients with Acute Decompensated Heart Failure Requiring Extra-Corporeal Membrane Oxygenation Therapy

Chronic systolic heart failure (HF) with acute decompensation can result in cardiogenic shock (CS) requiring short-term mechanical circulatory support. We sought to identify predictors of survival for acute decompensated HF (ADHF) patients requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Patients >18 years old treated at our institution with VA-ECMO from 2009 to 2018 for ADHF with CS were studied. Demographic, hemodynamic, and echocardiographic data were collected. The primary outcome was survival to discharge. Fifty-two patients received VA-ECMO for ADHF with CS; 24 (46.2%) survived. Seventeen (32.7%) had suffered cardiac arrest, and 37 (71.2%) were mechanically ventilated. Mean lactate was 4.33 ± 3.45 mmol/L, and patients were receiving 2.7 ± 1.2 vasopressor/inotropic infusions at ECMO initiation; these did not differ significantly between survivors and nonsurvivors. Pre-ECMO cardiac index was 1.84 ± 0.56L/min/m and 1.94 ± 0.63L/min/m in survivors and nonsurvivors, respectively (p = 0.57). In multivariable analysis, only diabetes mellitus (DM; OR, 13.25; CI, 1.42-123.40; p = 0.02) and mineralocorticoid receptor antagonist use (OR, 0.12; CI, 0.02-0.78; p = 0.03) were independent predictors of mortality. Nineteen (79.2%) survivors required durable ventricular assist device. Among ADHF patients receiving VA-ECMO, DM is a powerful predictor of outcomes while markers of clinical acuity including hemodynamics, vasopressor/inotrope use, and lactate are not. The vast majority of survivors required durable left-ventricular assist devices.

ECMO in cardiogenic shock and bridge to heart transplant

Purpose

The aim of this review is to discuss the role of extracorporeal membrane oxygenation (ECMO) in cardiogenic shock and its use to bridge patients to heart transplantation.

Methods and results

Consideration of published literature reveals indications for ECMO in cardiogenic shock and tools for patient selection, adequate evidence of its efficacy, its advantages when compared with other temporary mechanical circulatory support devices and details of its use as a bridge to decision, bridge to recovery, bridge to bridge (durable ventricular assist device) and bridge to heart transplant.

Conclusion

ECMO is invaluable in treating patients with medically refractory profound cardiogenic shock and allows for cardiac recovery or planning for permanent heart replacement treatments.

Comparison of the Hemodynamic Response to Intra-Aortic Balloon Counterpulsation in Patients With Cardiogenic Shock Resulting from Acute Myocardial Infarction Versus Acute Decompensated Heart Failure

The intra-aortic balloon pump (IABP) neither benefits nor harms patients with acute myocardial infarction (AMI) with cardiogenic shock (CS) but may stabilize those with chronic heart failure who decompensate into CS. We sought to compare its hemodynamic effects in these 2 populations. We performed a retrospective analysis of the hemodynamic effects of IABP for AMI or acute decompensated heart failure (ADHF) patients with hemodynamic evidence of CS. The primary outcome was cardiac output (CO) change following insertion. In total, 205 patients were treated for CS resulting from AMI (73; 35.6%) or ADHF (132; 64.4%). At baseline, both cohorts had significant hemodynamic compromise with mean arterial pressure 75.6 ± 12.3 mm Hg, CO 3.02 ± 0.84 L/min, and cardiac power index 0.26 ± 0.06 W/m²; these parameters were nearly identical between groups though ADHF-CS patients had a higher pre-IABP mean pulmonary artery (PA) pressure than AMI-CS patients. After IABP insertion, ADHF-CS patients had moderate CO augmentation whereas AMI-CS experienced almost no improvement (0.58 ± 0.79 L/min vs 0.12 ± 1.00 L/min; p = 0.0009). Intracardiac filling pressures were reduced by similar amounts in both cohorts. Systemic vascular resistance was reduced in patients with ADHF-CS but not in those with AMI-CS. In conclusion, following IABP insertion, ADHF-CS patients experience roughly a 5-fold greater CO augmentation compared with AMI-CS patients. Pre-IABP PA pressure differences and differential systemic vascular resistance reduction may explain these results and shed light on recent evidence supporting IABP use in ADHF-CS and curbing it in AMI-CS.

Midterm Outcomes of Bridge-to-Recovery Patients After Short-Term Mechanical Circulatory Support

BACKGROUND

The use of short-term mechanical circulatory support (ST-MCS) has increased for refractory cardiogenic shock. However, there are scant data about bridge-to-recovery patients.

METHODS

We retrospectively reviewed 502 patients with cardiogenic shock who received venoarterial extracorporeal membrane oxygenation or a temporary surgical ventricular assist device as ST-MCS between 2010 and 2016. There were 178 patients (35.5%) who survived through device explantation. Of these, 149 patients (29.7%) survived to discharge and were included for analysis. The primary outcome was midterm survival without undergoing heart replacement therapy.

RESULTS

In our bridge-to-recovery cohort, 101 patients (67.8%) were men, and the median age was 59 years (interquartile range, 51 to 67 years). Etiology of cardiogenic shock included postcardiotomy shock in 35.6% of patients (n = 53), allograft failure in 26.8% (n = 40), acute myocardial infarction (AMI) in 24.2% (n = 36), and other acute decompensated heart failure in 14.4% (n = 20). There were 24 major events (16.1%) recorded, including 21 patients who died and 3 patients who received heart replacement therapy during median follow-up of 306 days (interquartile range, 58.25 to 916.75 days). Overall freedom from event at 3 years was 74.2%. In subgroup analysis, AMI patients had a significantly worse freedom-from-event rate at 40.4% (p < 0.001). By univariate Cox analysis, AMI etiology (p = 0.003), length of ST-MCS (p = 0.06), blood urea nitrogen (p = 0.012), and left ventricular ejection fraction (p = 0.005) at discharge were predictors for adverse events.

CONCLUSIONS

The overall midterm outcome of patients explanted from ST-MCS is favorable except for AMI patients.

Palliative Care Consultation in Cardiogenic Shock Requiring Short-Term Mechanical Circulatory Support: A Retrospective Cohort Study

BACKGROUND

Little is known about palliative care consultation (PCC) for patients with cardiogenic shock requiring short-term mechanical circulatory support (STMCS).

OBJECTIVE

To describe the utilization of PCC in this population.

DESIGN

Retrospective cohort study in a university medical center intensive care unit (ICU).

SETTING/PARTICIPANTS

In total, 195 patients aged >18 years with cardiogenic shock requiring STMCS were included. The cohort was divided into three categories: no PCC, early PCC (within seven days of STMCS), and late PCC (eight or more days after STMCS). Follow-up occurred during the index hospitalization.

RESULTS

Mean age was 59.3 ± 13.9 years; 67.9% were men. Mean follow-up period was 33.8 ± 37.7 days. Overall inpatient mortality was 52.3%. Ninety-four patients (48.2%) received PCC; 49 (25.1%) and 45 (23.1%) received early and late PCCs, respectively. STMCS duration, ICU stay after STMCS, and hospital stay after STMCS were significantly shorter in the no PCC group than the early PCC group (4 vs. 12 days, p < 0.001; 11 vs. 19 days, p = 0.004; and 16 vs. 19 days, p = 0.031; respectively). ICU stay after STMCS and hospital stay after STMCS were significantly shorter in the early PCC group than the late PCC group (19 vs. 38 days, p < 0.001; 19 vs. 49 days, p < 0.001; respectively). However, time from initial PCC to discharge was not significantly different between early and late PCC groups (18 vs. 31 days, p = 0.13).

CONCLUSIONS

PCC was utilized in almost half of patients with cardiogenic shock requiring STMCS. PCC tends to occur toward the end of life regardless of the duration of STMCS. The optimal PCC timing remained unclear.