Clinical outcomes following Impella escalation in cardiogenic shock: a single-centre case series highlighting the gap between haemodynamic improvement and survival
Atsutaka Aratame
, Daisuke Kaku, Toshio Baba
Contributions: (I) Conception and design: A Aratame; (II) Administrative support: A Aratame, T Baba; (III) Provision of study materials or patients: All authors; (IV) Collection and assembly of data: A Aratame; (V) Data analysis and interpretation: A Aratame; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors.
Background: The use of temporary mechanical circulatory support has increased in patients with cardiogenic shock, particularly those with acute myocardial infarction (AMI). Impella provides effective left ventricular unloading and haemodynamic stabilisation. Escalation of such systems to higher-flow devices (e.g., Impella 5.0/5.5) has been proposed for patients with inadequate responses to Impella CP; however, the clinical impact and optimal timing of this approach remain unclear.
Case Description: We conducted a single-centre retrospective case series of patients who underwent Impella escalation between September 2020 and March 2026. Their clinical characteristics, haemodynamic responses, and outcomes were analysed. Among 130 patients treated with Impella CP, eight underwent upgrades. The underlying aetiology was AMI in six patients and myocarditis in two. Six patients required ECPELLA support. Following the upgrades, four patients were successfully weaned off extracorporeal membrane oxygenation (ECMO). Despite haemodynamic improvements, the overall outcomes were poor. Thirty-day survival was achieved in four patients; however, three experienced severe frailty (Clinical Frailty Scale scores of 7–8). Only one patient survived until hospital discharge. Infection-related complications, particularly sepsis, represented the leading causes of death. Device-related complications (e.g., access site infections) were observed in five patients, who required continuous negative-pressure wound therapy.
Conclusions: Impella escalation may facilitate haemodynamic stabilisation and ECMO-weaning in selected patients; however, this may not necessarily translate into improved survival outcomes. Non-haemodynamic factors (e.g., infection and frailty) likely play critical roles in determining patient outcomes. These findings should not be interpreted as evidence against Impella escalation itself, but rather highlight the importance of careful patient selection, comprehensive clinical assessment beyond haemodynamic parameters, and further investigation into the optimal timing of escalation.
Keywords: Impella escalation; cardiogenic shock; mechanical circulatory support; extracorporeal membrane oxygenation (ECMO); case series
Received: 10 April 2026; Accepted: 13 May 2026; Published online: 20 May 2026.
doi: 10.21037/acr-2026-0107
Highlight box
Key findings
• Impella escalation may facilitate haemodynamic stabilisation and weaning off extracorporeal membrane oxygenation (ECMO) in selected patients; however, this may not necessarily translate into improved survival outcomes.
What is known and what is new?
• The use of temporary mechanical circulatory support has increased in patients with cardiogenic shock, particularly those with acute myocardial infarction. Impella provides effective left ventricular unloading and haemodynamic stabilisation. Escalation of such systems to higher-flow devices (e.g., Impella 5.0/5.5) has been proposed for patients with inadequate responses to Impella CP; however, the timing and impact of this approach remain unclear.
• In this retrospective case series of eight patients who underwent Impella escalation at our institution between September 2020 and March 2026, four were successfully weaned off ECMO, four survived for 30 days post-procedure, and only one survived until hospital discharge.
What is the implication, and what should change now?
• Impella escalation should be considered in the context of patient selection and timing, as short-term haemodynamic stabilisation may not necessarily translate into favourable long-term outcomes, particularly when escalation is performed late.
• Earlier Impella escalation might address these poor outcomes.
Introduction
Temporary mechanical circulatory support (tMCS) has been used increasingly in patients with cardiogenic shock over recent years, particularly those with acute myocardial infarction (AMI). Among these devices, the Impella system (Abiomed, Danvers, MA, USA) has been widely used because of its superior left ventricular unloading effect and ability to improve haemodynamics (1,2). The DanGer Shock trial demonstrated improved 180-day survival with Impella CP compared with standard care alone in patients with AMI-related cardiogenic shock, thereby supporting its use in this setting (3).
In particular, Impella 5.0/5.5 can provide high-flow support and, owing to its axillary approach, facilitates prolonged use and early mobilisation (4). Consequently, its indications have expanded to include usage in perioperative settings for open cardiac surgery (5).
Observational studies and registry analyses have suggested that larger Impella devices may be associated with improved haemodynamics and short-term outcomes in certain patient populations (6,7). Escalation of such devices to higher-flow versions has also been suggested in patients who do not achieve adequate responses with Impella CP (8,9). However, the indications and optimal timing for Impella escalation remain controversial.
This case series aimed to describe the clinical course of patients who underwent Impella escalation at our institution, evaluate the relationship between haemodynamic improvement and subsequent clinical outcomes, and explore the challenges associated with patient selection and timing of escalation. We present this article in accordance with the PROCESS reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0107/rc) (10).
Case presentation
A total of 130 patients underwent Impella CP implantation at our institution between September 2020 and March 2026. Among these, eight underwent Impella escalation.
The patients’ characteristics are summarised in Table 1. The aetiology was AMI in six and myocarditis in two. Six patients required combined ECMO and Impella CP support (ECPELLA). All of those patients presented with haemodynamic shock on admission. ECMO was therefore initiated first to stabilise their haemodynamics, followed by Impella implantation.
Table 1
| Patient | Age (years) | Sex | Aetiology | Initial lactate (mmol/L) | ECMO | Initial LVEF (%) | Peak CK (U/L) |
|---|---|---|---|---|---|---|---|
| 1 | 72 | Male | LAD and RCA-related AMI | 8.7 | Yes | 10 | 19,945 |
| 2 | 78 | Male | Cx-related AMI | 6.0 | No | 40 | 2,550 |
| 3 | 73 | Male | Giant cell myocarditis | 4.1 | Yes | 10 | 467 |
| 4 | 76 | Male | LAD-related AMI | 4.5 | No | 10 | 7,712 |
| 5 | 68 | Female | Fulminant myocarditis | 2.3 | Yes | 15 | 1,522 |
| 6 | 80 | Male | LMT-related AMI | 2.2 | Yes | 10 | 8,301 |
| 7 | 66 | Male | AMI | 14.0 | Yes | 15 | 1,305 |
| 8 | 79 | Female | LMT-related AMI | 16.4 | Yes | 5–10 | 8,684 |
AMI, acute myocardial infarction; CK, creatine kinase; Cx, circumflex artery; ECMO, extracorporeal membrane oxygenation; LAD, left anterior descending artery; LMT, left main trunk coronary artery; LVEF, left ventricular ejection fraction; RCA, right coronary artery.
Among the two patients who did not require ECMO, one underwent surgical repair for oozing-type left ventricular rupture associated with circumflex artery AMI, and had relatively preserved haemodynamic and cardiac function preoperatively. The other had AMI in the left anterior descending artery region. Because the time from onset to hospital arrival was short, the patient’s haemodynamics were relatively stable, and Impella was introduced as the initial treatment without ECMO.
The details regarding the Impella upgrades are presented in Table 2. The patients were classified into early (n=4) and delayed upgrade (n=4) groups. In four of the patients, >1 week passed before upgrades were considered appropriate. Among these, none showed signs of end-organ hypoperfusion, but three had poor recovery of left ventricular function and thus received upgrades for long-term support. The remaining patient underwent surgery for left ventricular rupture and had a tendency toward postoperative bleeding; therefore, the upgrade was deferred until the bleeding stabilised, and was then performed to achieve long-term left ventricular unloading.
Table 2
| Patient | Indication for escalation | Time to upgrade (days) | Duration of Impella 5.5/5.0 support (days) | Concomitant haemodynamic support | Comments |
|---|---|---|---|---|---|
| 1 | Device limitation | 8 | 5 | None | – |
| 2 | Device limitation | 15 | 8 | None | Surgical repair of cardiac rupture |
| 3 | Device limitation | 8 | 26 | None | – |
| 4 | Device limitation | 7 | 14 | None | – |
| 5 | Haemodynamic failure | 3 | 7 | None | – |
| 6 | Haemodynamic failure | 2 | 6 | ECMO | Sever pulmonary oedema |
| 7 | Haemodynamic failure | 5 | 11 | None | MVR for papillary muscle rupture |
| 8 | Haemodynamic failure | 5 | 7 | ECMO | Sever pulmonary oedema |
ECMO, extracorporeal membrane oxygenation; MVR, mitral valve replacement.
Among the four patients who underwent early escalation, one had fulminant myocarditis and required escalation because of haemodynamic instability despite ECPELLA support. Two had AMI with extensive myocardial ischaemia caused by left main trunk occlusion, for whom it was decided that strong and prolonged circulatory support would be required. The remaining patient underwent mitral valve replacement for papillary muscle rupture associated with AMI, with the escalation being performed after postoperative stabilisation to achieve long-term left ventricular unloading.
Among the six patients who required ECPELLA, four were successfully weaned off ECMO after receiving escalation. Conversely, the remaining two patients developed severe pulmonary oedema before their Impella escalation. Adequate oxygenation could not be maintained in this subgroup, despite mechanical ventilation, Impella escalation, and renal replacement therapy, making weaning off ECMO difficult.
The patients’ clinical outcomes and complications are summarised in Table 3. Frailty was assessed using the 9-point Clinical Frailty Scale (CFS) (11). Thirty-day survival was achieved in four patients, among whom three had CFS scores of 7–8. Only one patient survived until hospital discharge.
Table 3
| Patient | Survival (30-day) | Clinical frailty scale (30-day) | In-hospital outcome | Cause of death | Wound infection (site) | Renal replacement therapy (days) | LVEF in 2 weeks (%) |
|---|---|---|---|---|---|---|---|
| 1 | Death | – | Death | Multiple cerebral infarction | – | 14 | 20 |
| 2 | In hospital | 7 | Death | Sepsis (MRSE) | Femoral | 76 | 40 |
| 3 | In hospital | 7 | Death | Sepsis (MRSA) | Femoral | 59 | 50 |
| 4 | In hospital | 8 | Death | Sepsis (MRSE) | Femoral | 35 | 15 |
| 5 | In hospital | 3 | Transferred for rehabilitation | – | Graft-related | 26 | 30 |
| 6 | Death | – | Death | Gastrointestinal bleeding | – | 9 | – |
| 7 | Death | – | Death | Cardiac rupture | Femoral | 17 | 15 |
| 8 | Death | – | Death | Heart failure | – | 12 | – |
LVEF, left ventricular ejection fraction; MRSA, methicillin-resistant Staphylococcus aureus; MRSE, methicillin-resistant Staphylococcus epidermidis.
The causes of death were multiple cerebral infarction leading to withdrawal of treatment in one patient, sepsis in three, uncontrollable gastrointestinal bleeding in one, cardiac rupture in one, and heart failure in one (Figure 1). Infection-related complications occurred in four patients at the ECMO or Impella insertion sites (i.e., the femoral region), which were treated using negative pressure wound therapy. One patient developed an Impella-related vascular graft infection after the removal of an Impella 5.0/5.5. All of the patients required renal replacement therapy.
All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patients or their families for the publication of this case series. A copy of the written consent is available for review by the editorial office of this journal.
Discussion
In this case series, Impella escalation facilitated ECMO-weaning in some patients and contributed to haemodynamic stabilisation, as reflected by improvements in cardiac index, reduction of vasoactive-inotropic support, normalisation of lactic acid and stable mean arterial pressure. However, the overall outcomes were poor, with only one patient surviving until hospital discharge. Notably, most of the deaths were attributable to infection-related complications rather than circulatory failure (Figure 1). These poor outcomes require careful reflection on our treatment strategy, particularly regarding the timing of escalation, assessment of ECMO weaning feasibility, and prevention of complications associated with prolonged intensive care.
Infection was the leading cause of death in this study. Particularly in patients who required ECPELLA, femoral access site infection, prolonged renal replacement therapy, total parenteral nutrition, and frequent catheter exchanges may have contributed to the long-term use of antibiotics, leading to the development of multidrug-resistant bacteraemia. These findings suggest that in patients with critical illnesses who require tMCS, intensive care-related factors may significantly influence long-term outcomes even after haemodynamic stabilisation.
In our patients in whom weaning off ECMO was impractical, severe pulmonary oedema persisted and adequate oxygenation could not be achieved with mechanical ventilation alone. Although cardiogenic pulmonary congestion due to persistent shock may have contributed to this condition, increased vascular permeability associated with shock-induced hypercytokinaemia, as well as substantial transfusion and fluid administration required to maintain tMCS, may also have played important roles.
As a potential strategy to address these poor outcomes, earlier escalation to higher-capacity Impella support may help reduce complications associated with prolonged intensive care. First, earlier escalation may facilitate mobilisation, extubation, reduction of catecholamine requirements, and removal of central venous catheters and other invasive lines. Second, in patients receiving ECPELLA, earlier escalation may improve left ventricular unloading and pulmonary congestion, thereby increasing the likelihood of ECMO weaning before pulmonary oedema due to increased vascular permeability becomes established. Third, previous studies have suggested that high-capacity Impella support may be associated with improved survival and lower complication rates, including fewer ischaemic and major bleeding events, compared with low-capacity Impella support (12,13). These considerations support the need for timely reassessment of Impella CP support adequacy and ECMO weaning feasibility, rather than prolonged continuation of insufficient tMCS.
Our patients who were escalated after ≥1 week were from the earlier phase of our experience with the device, corresponding to the first 2–3 years following its introduction at our institution. With the accumulation of published evidence regarding the benefits of large-capacity Impella (12,13), as well as increasing institutional experience with it, the escalation interval has shortened. This change may be attributable to factors mentioned above. In our study, escalation to Impella 5.0/5.5 has been considered in patients who cannot be weaned from Impella CP and require ongoing mechanical circulatory support beyond the practical limitations of Impella CP. However, haemodynamic stabilisation after escalation has not necessarily translated into favourable long-term outcomes. These findings should not be interpreted as evidence against escalation itself, but rather highlight the need to clarify optimal patient selection and timing of escalation.
These observations also highlight the importance of timely reassessment of therapeutic goals, patient selection, and candidacy for durable therapies when considering escalation to higher-capacity Impella support.
Impella CP is generally considered effective for managing cardiogenic shock (1-3); therefore, the threshold for its use in clinical practice tends to be low. On the other hand, Impella escalation may be considered more carefully due to the invasiveness associated with the surgical procedures and elongation of MCS. Conventional haemodynamic parameters such as cardiac index, lactate levels, and vasopressor requirements have been suggested as useful indications (8,9,14). However, the decision to perform Impella escalation should not rely solely on these parameters but also on a comprehensive assessment incorporating the likelihood of ECMO-weaning, infection risk, nutritional status, frailty, and the potential for mobilisation. Additionally, delayed escalation may contribute to failure to improve haemodynamic status and deterioration of patients’ condition, leading to poor outcomes.
This study was subject to several key limitations worth noting. It was a single-centre retrospective case series with a small sample size, so our findings should be interpreted cautiously. Additionally, detailed invasive haemodynamic data before and after Impella escalation were not available in all patients, preventing quantitative assessment using uniform haemodynamic parameters. However, the major strength of this study lies in our detailed evaluation of the individual patients’ clinical courses, which are often not captured in larger-scale studies.
These detailed clinical observations suggest that non-haemodynamic factors (e.g., infection and frailty) play critical roles in determining patient outcomes. Despite the limited sample size, this study may provide meaningful insights into the clinical courses of patients who undergo Impella escalation. Further multicentre studies are warranted to validate our findings.
Conclusions
In this case series, Impella escalation facilitated haemodynamic stabilisation and ECMO-weaning in selected patients with cardiogenic shock. However, the patient outcomes were largely determined by non-haemodynamic factors, particularly infection and frailty. Earlier Impella escalation might have addressed these poor outcomes. Therefore, decisions regarding Impella escalation should extend beyond conventional haemodynamic parameters and incorporate comprehensive assessments, including the likelihood of ECMO-weaning, infection risk, nutritional status, and functional recovery.
Acknowledgments
We would like to thank Editage (http://www.editage.com) for editing and reviewing this manuscript for English language.
Footnote
Reporting Checklist: The authors have completed the PROCESS reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0107/rc
Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0107/prf
Funding: None.
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-2026-0107/coif). The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patients or their families for the publication of this case series. A copy of the written consent is available for review by the editorial office of this journal.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
References
- Masiero G, Arturi F, Panza A, et al. Mechanical Circulatory Support with Impella: Principles, Evidence, and Daily Practice. J Clin Med 2024;13:4586. [Crossref] [PubMed]
- Attinger-Toller A, Bossard M, Cioffi GM, et al. Ventricular Unloading Using the Impella(TM) Device in Cardiogenic Shock. Front Cardiovasc Med 2022;9:856870. [Crossref] [PubMed]
- Møller JE, Engstrøm T, Jensen LO, et al. Microaxial Flow Pump or Standard Care in Infarct-Related Cardiogenic Shock. N Engl J Med 2024;390:1382-93. [Crossref] [PubMed]
- Tarabichi S, Ikegami H, Russo MJ, et al. The role of the axillary Impella 5.0 device on patients with acute cardiogenic shock. J Cardiothorac Surg 2020;15:218. [Crossref] [PubMed]
- Eisenga J, McCullough K, Moubarak G, et al. The use of perioperative Impella 5.5 support in high-risk cardiac surgery: a retrospective cohort study. J Thorac Dis 2024;16:6045-51. [Crossref] [PubMed]
- Hong Y, Agrawal N, Hess NR, et al. Outcomes of Impella 5.0 and 5.5 for cardiogenic shock: A single-center 137 patient experience. Artif Organs 2024;48:771-80. [Crossref] [PubMed]
- Nakamura M, Imamura T, Nakagaito M, et al. Association Between Impella Device Type and Short-Term Prognosis in Patients with Acute Myocardial Infarction-Related Cardiogenic Shock Receiving ECPELLA Support. Int Heart J 2024;65:1049-57. [Crossref] [PubMed]
- Geller BJ, Sinha SS, Kapur NK, et al. Escalating and De-escalating Temporary Mechanical Circulatory Support in Cardiogenic Shock: A Scientific Statement From the American Heart Association. Circulation 2022;146:e50-68. [Crossref] [PubMed]
- Saito S, Okubo S, Matsuoka T, et al. Impella - Current issues and future expectations for the percutaneous, microaxial flow left ventricular assist device. J Cardiol 2024;83:228-35. [Crossref] [PubMed]
- Agha RA, Sohrabi C, Mathew G, et al. The PROCESS 2020 Guideline: Updating Consensus Preferred Reporting Of CasESeries in Surgery (PROCESS) Guidelines. Int J Surg 2020;84:231-5. [Crossref] [PubMed]
- Rockwood K, Theou O. Using the Clinical Frailty Scale in Allocating Scarce Health Care Resources. Can Geriatr J 2020;23:210-5. [Crossref] [PubMed]
- Fried J, Farr M, Kanwar M, et al. Clinical outcomes among cardiogenic shock patients supported with high-capacity Impella axial flow pumps: A report from the Cardiogenic Shock Working Group. J Heart Lung Transplant 2024;43:1478-88. [Crossref] [PubMed]
- Haberman D, Verma B, Abusnina W, et al. Low- Versus High-capacity Impella for CS After AMI: A Systematic Review and Pooled Data Analysis. Catheter Cardiovasc Interv 2026;107:1246-53. [Crossref] [PubMed]
- Aludaat C, Dovonou E, Besnier E, et al. Upgrading extra corporeal life support to ECMELLA using Impella 5.0 in rescued INTERMACS 1 patients, lactate level matters! J Thorac Dis 2023;15:3079-88. [Crossref] [PubMed]
Cite this article as: Aratame A, Kaku D, Baba T. Clinical outcomes following Impella escalation in cardiogenic shock: a single-centre case series highlighting the gap between haemodynamic improvement and survival. AME Case Rep 2026;10:127.
