The "TIDE"-Algorithm for the Weaning of Patients With Cardiogenic Shock and Temporarily Mechanical Left Ventricular Support With Impella Devices. A Cardiovascular Physiology-Based Approach

Objectives: Mechanical circulatory support (MCS) is often required to stabilize therapy-refractory cardiogenic shock patients. Left ventricular (LV) unloading by mechanical ventricular support (MVS) via percutaneous devices, such as with Impella® axial pumps, alone or in combination with extracorporeal life support (ECLS, ECMELLA approach), has emerged as a potential clinical breakthrough in the field. While the weaning from MCS is essentially based on the evaluation of circulatory stability of patients, weaning from MVS holds a higher complexity, being dependent on bi-ventricular function and its adaption to load. As a result of this, weaning from MVS is mostly performed in the absence of established algorithms. MVS via Impella is applied in several cardiogenic shock etiologies, such as acute myocardial infarction (support over days) or acute fulminant myocarditis (prolonged support over weeks, PROPELLA). The time point of weaning from Impella in these cohorts of patients remains unclear. We here propose a novel cardiovascular physiology-based weaning algorithm for MVS.

Methods: The proposed algorithm is based on the experience gathered at our center undergoing an Impella weaning between 2017 and 2020. Before undertaking a weaning process, patients must had been ECMO-free, afebrile, and euvolemic, with hemodynamic stability guaranteed in the absence of any inotropic support. The algorithm consists of 4 steps according to the acronym TIDE: (i) Transthoracic echocardiography under full Impella-unloading; (ii) Impella rate reduction in single 8–24 h-steps according to patients hemodynamics (blood pressure, heart rate, and ScVO₂), including a daily echocardiographic assessment at minimal flow (P2); (iii) Dobutamine stress-echocardiography; (iv) Right heart catheterization at rest and during Exercise-testing via handgrip. We here present clinical and hemodynamic data (including LV conductance data) from paradigmatic weaning protocols of awake patients admitted to our intensive care unit with cardiogenic shock. We discuss the clinical consequences of the TIDE algorithm, leading to either a bridge-to-recovery, or to a bridge-to-permanent LV assist device (LVAD) and/or transplantation. With this protocol we were able to wean 74.2% of the investigated patients successfully. 25.8% showed a permanent weaning failure and became LVAD candidates.

Conclusions: The proposed novel cardiovascular physiology-based weaning algorithm is based on the characterization of the extent and sustainment of LV unloading reached during hospitalization in patients with cardiogenic shock undergoing MVS with Impella in our center. Prospective studies are needed to validate the algorithm.

IMPELLA® or Extracorporeal Membrane Oxygenation for Left Ventricular Dominant Refractory Cardiogenic Shock

Mechanical circulatory support (MCS) devices are effective tools in managing refractory cardiogenic shock (CS). Data comparing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and IMPELLA^® are however scarce. We aimed to assess outcomes of patients implanted with these two devices and eligible to both systems. From 2004 to 2020, we retrospectively analyzed 128 patients who underwent VA-ECMO or IMPELLA^® in our institution for refractory left ventricle (LV) dominant CS. All patients were eligible to both systems: 97 patients were first implanted with VA-ECMO and 31 with IMPELLA^®. The primary endpoint was 30-day all-cause death. VA-ECMO patients were younger (52 vs. 59.4, p = 0.006) and had a higher lactate level at baseline than those in the IMPELLA^® group (6.84 vs. 3.03 mmol/L, p < 0.001). Duration of MCS was similar between groups (9.4 days vs. 6 days in the VA-ECMO and IMPELLA^® groups respectively, p = 0.077). In unadjusted analysis, no significant difference was observed between groups in 30-day mortality: 43.3% vs. 58.1% in the VA-ECMO and IMPELLA^® groups, respectively (p = 0.152). After adjustment, VA-ECMO was associated with a significant reduction in 30-day mortality (HR = 0.25, p = 0.004). A higher rate of MCS escalation was observed in the IMPELLA^® group: 32.3% vs. 10.3% (p = 0.003). In patients eligible to either VA-ECMO or IMPELLA^® for LV dominant refractory CS, VA-ECMO was associated with improved survival rate and a lower need for escalation.

Impella versus extracorporal life support in cardiogenic shock: a propensity score adjusted analysis

Aims

The mortality in cardiogenic shock (CS) is high. The role of specific mechanical circulatory support (MCS) systems is unclear. We aimed to compare patients receiving Impella versus ECLS (extracorporal life support) with regard to baseline characteristics, feasibility, and outcomes in CS.

Methods and results

This is a retrospective cohort study including CS patients over 18 years with a complete follow‐up of the primary endpoint and available baseline lactate level, receiving haemodynamic support either by Impella 2.5 or ECLS from two European registries. The decision for device implementation was made at the discretion of the treating physician. The primary endpoint of this study was all‐cause mortality at 30 days. A propensity score for the use of Impella was calculated, and multivariable logistic regression was used to obtain adjusted odds ratios (aOR).

In total, 149 patients were included, receiving either Impella (n = 73) or ECLS (n = 76) for CS. The feasibility of device implantation was high (87%) and similar (aOR: 3.14; 95% CI: 0.18–56.50; P = 0.41) with both systems. The rates of vascular injuries (aOR: 0.95; 95% CI: 0.10–3.50; P = 0.56) and bleedings requiring transfusions (aOR: 0.44; 95% CI: 0.09–2.10; P = 0.29) were similar in ECLS patients and Impella patients. The use of Impella or ECLS was not associated with increased odds of mortality (aOR: 4.19; 95% CI: 0.53–33.25; P = 0.17), after correction for propensity score and baseline lactate level. Baseline lactate level was independently associated with increased odds of 30 day mortality (per mmol/L increase; OR: 1.29; 95% CI: 1.14–1.45; P < 0.001).

Conclusions

In CS patients, the adjusted mortality rates of both ECLS and Impella were high and similar. The baseline lactate level was a potent predictor of mortality and could play a role in patient selection for therapy in future studies. In patients with profound CS, the type of device is likely to be less important compared with other parameters including non‐cardiac and neurological factors.

Budget Impact Associated with the Introduction of the Impella 5.0® Mechanical Circulatory Support Device for Cardiogenic Shock in France

AIM

Cardiogenic shock (CS), if not diagnosed and treated rapidly, can lead to irreversible multiorgan damage and death. An economic analysis was conducted to determine the budget impact of the introduction of Impella 5.0®, a mechanical circulatory support (MCS) device that directly unloads the left ventricle, into clinical practice in patients with left ventricular CS in France.

METHODS

A budget impact model was developed to compare the cost of Impella 5.0 with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) from the perspective of the French national healthcare insurer. Costs associated with Impella 5.0, plus complication-related costs for VA-ECMO or Impella 5.0 from 2019 were included and clinical input data relating to complication rates and time spent on device were sourced from published literature. Extensive scenario and one-way deterministic sensitivity analyses were performed to explore the influence of uncertainty around key input parameters.

RESULTS

Over a time horizon of 5 years, the introduction of Impella 5.0 was associated with cumulative savings of EUR 4.3 million. The results were driven by the lower risk of device-related complications associated with Impella 5.0. Savings were apparent from Year 1 onwards, with savings in excess of EUR 375,000 projected in Year 1 alone. On a per-patient level, in Year 1, estimated savings with the introduction of Impella 5.0 totaled EUR 616 per patient. Sensitivity analyses showed that the findings of the analysis were robust.

CONCLUSION

The Impella 5.0 device was associated with cumulative cost savings in excess of EUR 4 million over a 5-year period compared with current practice. Projected savings were driven by a lower rate of device-related complications with Impella 5.0 compared with VA-ECMO.

Impella CP Implantation during Cardiopulmonary Resuscitation for Cardiac Arrest: A Multicenter Experience

BACKGROUND

Impella CP is a left ventricular pump which may serve as a circulatory support during cardiopulmonary resuscitation (CPR) for cardiac arrest (CA). Nevertheless, the survival rate and factors associated with survival in patients undergoing Impella insertion during CPR for CA are unknown.

METHODS

We performed a retrospective multicenter international registry of patients undergoing Impella insertion during on-going CPR for in- or out-of-hospital CA. We recorded immediate and 30-day survival with and without neurologic impairment using the cerebral performance category score and evaluated the factors associated with survival.

RESULTS

Thirty-five patients had an Impella CP implanted during CPR for CA. Refractory ventricular arrhythmias were the most frequent initial rhythm (65.7%). In total, 65.7% of patients immediately survived. At 30 days, 45.7% of patients were still alive. The 30-day survival rate without neurological impairment was 37.1%. In univariate analysis, survival was associated with both an age < 75 years and a time from arrest to CPR ≤ 5 min (p = 0.035 and p = 0.008, respectively).

CONCLUSIONS

In our multicenter registry, Impella CP insertion during ongoing CPR for CA was associated with a 37.1% rate of 30-day survival without neurological impairment. The factors associated with survival were a young age and a time from arrest to CPR ≤ 5 min.

Comparison of mechanical circulatory support with venoarterial extracorporeal membrane oxygenation or Impella for patients with cardiogenic shock: a propensity-matched analysis

BACKGROUND

Percutaneous mechanical circulatory devices are increasingly used in patients with cardiogenic shock (CS). As evidence from randomized studies comparing these devices are lacking, optimal choice of the device type is unclear. Here we aim to compare outcomes of patients with CS supported with either Impella or vaECMO.

METHODS

Retrospective single-center analysis of patients with CS, from September 2014 to September 2019. Patients were assisted with either Impella 2.5/CP or vaECMO. Patients supported ultimately with both devices were analyzed according to the first device implanted. Primary outcomes were hospital and 6-month survival. Secondary endpoints were complications. Survival outcomes were compared using propensity-matched analysis to account for differences in baseline characteristics between both groups.

RESULTS

A total of 423 patients were included (Impella, n = 300 and vaECMO, n = 123). Survival rates were similar in both groups (hospital survival: Impella 47.7% and vaECMO 37.3%, p = 0.07; 6-month survival Impella 45.7% and vaECMO 35.8%, p = 0.07). There was no significant difference in survival rates, even after adjustment for baseline differences (hospital survival: Impella 50.6% and vaECMO 38.6%, p = 0.16; 6-month survival Impella 45.8% and vaECMO 38.6%, p = 0.43). Access-site bleeding and leg ischemia occurred more frequently in patients with vaECMO (17% versus 7.3%, p = 0.004; 17% versus 7.7%, p = 0.008).

CONCLUSIONS

In this retrospective analysis of patients with CS, treatment with Impella 2.5/CP or vaECMO was associated with similar hospital and 6-month survival rates. Device-related access-site vascular complications occurred more frequently in the vaECMO group. A randomized trial is warranted to examine the effects of these devices on outcomes and to determine the optimal device choice in patients with CS.

Perioperative care in cardiac surgery

As mortality is now low for many cardiac surgical procedures, there has been an increasing focus on patient centered outcomes such as recovery and quality of life. The Enhanced Recovery After Surgery (ERAS) cardiac society recently published the first set of guidelines for cardiac surgery which will be useful as a starting point to help translate this philosophy for the benefit of those undergoing cardiac surgery. At the same time there are many advances in other areas such as mechanical circulation, diagnostics and quality metrics. We intend here to present a balanced and evidenced based review of selected aspects of current practice, encompassing both UK and international perioperative care with a focus on recent advances. For the convenience of the reader we will adopt the conventional perioperative preoperative, intraoperative and postoperative phases of care. The focus of cardiac surgical practice needs to evolve from mortality to recovery. Those specialists who work in cardiac anaesthesia and critical care are well placed to contribute to these changes. Accompanying this work is the development of technologies to improve recognition of and intervention to prevent early organ dysfunction. Measuring, benchmarking and publishing quality outcomes from cardiac surgical centres is likely to improve services and benefit our patients.

The science of safety: complications associated with the use of mechanical circulatory support in cardiogenic shock and best practices to maximize safety

Acute mechanical circulatory support (MCS) devices are widely used in cardiogenic shock (CS) despite a lack of high-quality clinical evidence to guide their use. Multiple devices exist across a spectrum from modest to complete support, and each is associated with unique risks. In this review, we summarize existing data on complications associated with the three most widely used acute MCS platforms: the intra-aortic balloon pump (IABP), Impella systems, and veno-arterial extracorporeal membrane oxygenation (VA-ECMO). We review evidence from available randomized trials and highlight challenges comparing complication rates from case series and comparative observational studies where a lack of granular data precludes appropriate matching of patients by CS severity. We further offer a series of best practices to help shock practitioners minimize the risk of MCS-associated complications and ensure the best possible outcomes for patients.

Short-term mechanical circulatory support (intra-aortic balloon pump, Impella, extracorporeal membrane oxygenation, TandemHeart): a review

Cardiogenic shock remains a major cause of morbidity and mortality for patients with acute myocardial infarction and advanced heart failure. Intra-aortic balloon pump has been the most widely used short-term mechanical circulatory support device to rapidly stabilize hemodynamics. However, it provides modest support, current evidence does not show a decrease in mortality, and the latest guidelines no longer recommend its routine use. Several percutaneous mechanical circulatory support devices have been introduced into clinical practice (Impella, extracorporeal membrane oxygen, TandemHeart), providing a greater level of hemodynamic support. These resource-intensive devices demand a careful selection of patients that stand to benefit the most. Premature initiation of mechanical circulatory support exposes the patient to unnecessary risk, whereas delaying therapy leads to irreversible end-organ injury, rendering any intervention medically futile. Cannulation methods, pump designs, and circuit configurations differ between devices, as do the adverse effects and physiological impact on the myocardium, which needs to be factored into consideration before deployment on the patient in cardiogenic shock. This article will review the commonly used percutaneous mechanical circulatory support devices in the setting of cardiogenic shock, compare their advantages and disadvantages, evaluate key clinical trials, and discuss a practical approach to guide clinicians' decision and management.

Prognostic Impact of Active Mechanical Circulatory Support in Cardiogenic Shock Complicating Acute Myocardial Infarction, Results from the Culprit-Shock Trial

OBJECTIVES

To analyze the use and prognostic impact of active mechanical circulatory support (MCS) devices in a large prospective contemporary cohort of patients with cardiogenic shock (CS) complicating acute myocardial infarction (AMI).

BACKGROUND

Although increasingly used in clinical practice, data on the efficacy and safety of active MCS devices in patients with CS complicating AMI are limited.

METHODS

This is a predefined subanalysis of the CULPRIT-SHOCK randomized trial and prospective registry. Patients with CS, AMI and multivessel coronary artery disease were categorized in two groups: (1) use of at least one active MCS device vs. (2) no active MCS or use of intra-aortic balloon pump (IABP) only. The primary endpoint was a composite of all-cause death or renal replacement therapy at 30 days.

RESULTS

Two hundred of 1055 (19%) patients received at least one active MCS device (n = 112 Impella^®; n = 95 extracorporeal membrane oxygenation (ECMO); n = 6 other devices). The primary endpoint occurred significantly more often in patients treated with active MCS devices compared with those without active MCS devices (142 of 197, 72% vs. 374 of 827, 45%; p < 0.001). All-cause mortality and bleeding rates were significantly higher in the active MCS group (all p < 0.001). After multivariable adjustment, the use of active MCS was significantly associated with the primary endpoint (odds ratio (OR) 4.0, 95% confidence interval (CI) 2.7-5.9; p < 0.001).

CONCLUSIONS

In the CULPRIT-SHOCK trial, active MCS devices were used in approximately one fifth of patients. Patients treated with active MCS devices showed worse outcome at 30 days and 1 year.

Impact of concomitant vasoactive treatment and mechanical left ventricular unloading in a porcine model of profound cardiogenic shock

BACKGROUND

Concomitant vasoactive drugs are often required to maintain adequate perfusion pressure in patients with acute myocardial infarction (AMI) and cardiogenic shock (CS) receiving hemodynamic support with an axial flow pump (Impella CP).

OBJECTIVE

To compare the effect of equipotent dosages of epinephrine, dopamine, norepinephrine, and phenylephrine on cardiac work and end-organ perfusion in a porcine model of profound ischemic CS supported with an Impella CP.

METHODS

CS was induced in 10 pigs by stepwise intracoronary injection of polyvinyl microspheres. Hemodynamic support with Impella CP was initiated followed by blinded crossover to vasoactive treatment with norepinephrine (0.10 μg/kg/min), epinephrine (0.10 μg/kg/min), or dopamine (10 μg/kg/min) for 30 min each. At the end of the study, phenylephrine (10 μg/kg/min) was administered for 20 min. The primary outcome was cardiac workload, a product of pressure-volume area (PVA) and heart rate (HR), measured using the conductance catheter technique. End-organ perfusion was assessed by measuring venous oxygen saturation from the pulmonary artery (SvO₂), jugular bulb, and renal vein. Treatment effects were evaluated using multilevel mixed-effects linear regression.

RESULTS

All catecholamines significantly increased LV stroke work and cardiac work, dopamine to the greatest extend by 341.8 × 10³ (mmHg × mL)/min [95% CI (174.1, 509.5), p < 0.0001], and SvO₂ significantly improved during all catecholamines. Phenylephrine, a vasoconstrictor, caused a significant increase in cardiac work by 437.8 × 10³ (mmHg × mL)/min [95% CI (297.9, 577.6), p < 0.0001] due to increase in potential energy (p = 0.001), but no significant change in LV stroke work. Also, phenylephrine tended to decrease SvO₂ (p = 0.063) and increased arterial lactate levels (p = 0.002).

CONCLUSION

Catecholamines increased end-organ perfusion at the expense of increased cardiac work, most by dopamine. However, phenylephrine increased cardiac work with no increase in end-organ perfusion.

Complications of Temporary Percutaneous Mechanical Circulatory Support for Cardiogenic Shock: An Appraisal of Contemporary Literature

Cardiogenic shock (CS) is associated with hemodynamic compromise and end-organ hypoperfusion due to a primary cardiac etiology. In addition to vasoactive medications, percutaneous mechanical circulatory support (MCS) devices offer the ability to support the hemodynamics and prevent acute organ failure. Despite the wide array of available MCS devices for CS, there are limited data on the complications from these devices. In this review, we seek to summarize the complications of MCS devices in the contemporary era. Using a systems-based approach, this review covers domains of hematological, neurological, vascular, infectious, mechanical, and miscellaneous complications. These data are intended to provide a balanced narrative and aid in risk-benefit decision-making in this acutely ill population.

A novel mortality risk score predicting intensive care mortality in cardiogenic shock patients treated with veno-arterial extracorporeal membrane oxygenation

PURPOSE

Mortality after veno-arterial extracorporeal membrane oxygenation (VA-ECMO) implantation remains a major problem in patients with cardiogenic shock. Our objective was to assess the utility of the SOFA score in combination with markers of right ventricular (RV) dysfunction in predicting mortality in the ICU.

MATERIALS AND METHODS

Data were retrospectively obtained from all adult patients (n=103) who were treated with VA-ECMO between November 2004 and January 2016. The primary outcome of this study was ICU mortality after VA-ECMO implantation. Using the clinical, demographic and echocardiographic data, we developed a novel mortality risk score, the SOFA-RV score, which combine RV-function to the SOFA score at the time of VA-ECMO implantation.

RESULTS

Out of 103 patients, 37 (36%) died in the ICU. The median duration of VA-ECMO support was 7 days [IQR 4-11], mean age 49 ± 16 years, and 54% were male. SOFA-RV score has an AUC of 0.70, and was significantly better than SOFA alone (AUC of 0.57) in predicting ICU mortality. In addition, SAVE and MELD scores were not able to predict ICU mortality.

CONCLUSION

Adding RV-function to the existing SOFA score improves significantly the prediction of ICU mortality in patients on VA-ECMO. Dedicated evaluation of RV function in patients with VA-ECMO is therefore recommended.