What question did this study set out to answer?

The central aim is to determine if elective left ventricular unloading improves outcomes during complex percutaneous coronary intervention in patients with severe left ventricular dysfunction.

April 1, 2026

Left Ventricular Unloading in High-Risk Percutaneous Coronary Intervention

Q: What is the clinical evidence from this study?

Study design: RCT. Population: Severe left ventricular dysfunction and extensive coronary artery disease (n=300). Intervention: Elective unloading with a microaxial flow pump vs. Standard care. Primary outcome: Hierarchical composite of death from any cause, disabling stroke, spontaneous myocardial infarction, hospitalization for cardiovascular causes, or periprocedural myocardial injury at a minimum of 12 months (win ratio 0.85, 95% CI 0.63 to 1.15, p=0.30).

Trending Research#1 this week

Presented as late-breaking at ACC.26 with simultaneous NEJM publication; generated extensive coverage from ACC, TCTMD, SCAI (top stories in March 2026 roundups); multiple expert threads and debates on X questioning routine Impella use in CHIP procedures; challenges rapid adoption of protected PCI; high clinical practice disruption signal with >15 press releases and news articles.

Social attention

Preprint velocity

News coverage

Conference

Expert commentary

Expert Consensus

+Strong agreement that routine elective LV unloading with a microaxial flow pump (Impella CP) does not improve the primary hierarchical composite endpoint or reduce major adverse events in patients with severe LV dysfunction (LVEF ~27%) undergoing complex high-risk PCI, as shown by the neutral win ratio (0.85, p=0.30) in CHIP-BCIS3 (moderate-to-strong agreement across editorial, discussants, and social commentary).
+Broad consensus that the trial provides sufficient evidence against routine 'protected PCI' with Impella in stabilized patients without hemodynamic instability or cardiogenic shock; selective use is preferred (echoed in NEJM editorial, Mehran, Kirtane, Perera, and Sperry).
+Agreement that procedural strategy matters: more complete revascularization during index procedure in the Impella arm did not translate to better outcomes and may have contributed to harm signals; staging PCI is likely preferable (noted by Kirtane, PCR coverage, and X discussions).

Open Questions

?Debate on the role of periprocedural MI in the primary composite endpoint, with some interventionalists (e.g., Salman Arain on X) questioning if it unfairly disadvantaged the Impella arm given potential device-related enzyme elevations (poll and thread discussion).
?Whether observed harm (higher CV death, HR 1.91) is directly due to the device (bleeding, vascular issues, hemolysis) versus behavioral changes in operators pursuing more aggressive revascularization under 'protection' (highlighted by Kirtane and Mehran as an open question).
?Degree of applicability: some note the trial population was very high-risk but not in shock, leaving room for individualized use in select unstable cases despite overall negative results (implicit in Sperry and Arain posts vs. stricter editorial stance).

Key implication: If adopted, this negative result for routine use in CHIP-BCIS3 should markedly curtail reflexive Impella deployment for 'protected PCI' in stable high-risk cases (where most implants currently occur per registry data), reducing device-related complications while encouraging staged procedures and hemodynamic assessment-driven selective support, pending PROTECT IV results.

Key Result

Elective unloading with a microaxial flow pump during complex PCI did not improve the primary composite outcome compared to standard care (win ratio 0.85; 95% CI 0.63-1.15; P=0.30).

Key Points

The central aim is to determine if elective left ventricular unloading improves outcomes during complex percutaneous coronary intervention in patients with severe left ventricular dysfunction.
Randomly assigned 300 patients with severe left ventricular dysfunction to either microaxial flow pump or standard care during PCI.
Primary outcome assessed was a composite of death, disabling stroke, myocardial infarction, hospitalization for cardiovascular causes, or myocardial injury after 12 months.
Follow-up duration was a median of 22 months.
36.6% of pairwise comparisons favored the microaxial flow pump strategy, while 43.0% favored standard care (win ratio, 0.85; 95% CI, 0.63 to 1.15; P=0.30).
Death from any cause occurred in 47 patients receiving the pump and 33 receiving standard care (hazard ratio, 1.54; 95% CI, 0.99 to 2.41).
No significant difference in bleeding or vascular complications was found between groups.

Study Design

Type

RCT

Randomization

1:1

Structured PICO

Does elective left ventricular unloading with a microaxial flow pump improve clinical outcomes in patients with severe left ventricular dysfunction and extensive coronary artery disease undergoing complex PCI?

Population

300 patients with severe left ventricular dysfunction and extensive coronary artery disease undergoing planned complex percutaneous coronary intervention (PCI)

Intervention

Elective left ventricular unloading with a microaxial flow pump during planned complex PCI

Comparator

Standard care during planned complex PCI

Outcome

Hierarchical composite of death from any cause, disabling stroke, spontaneous myocardial infarction, hospitalization for cardiovascular causes, or periprocedural myocardial injury at a minimum of 12 months (analyzed according to a win ratio)composite

Routine elective use of a microaxial flow pump during complex PCI in patients with severe left ventricular dysfunction does not improve major adverse clinical outcomes compared to standard care.

Abstract

BACKGROUND: Complex percutaneous coronary intervention (PCI) in patients with severely impaired left ventricular function carries a high risk of death and complications. Whether percutaneous left ventricular unloading improves outcomes remains unclear. METHODS: We randomly assigned 300 patients with severe left ventricular dysfunction and extensive coronary artery disease in a 1:1 ratio to a strategy of elective unloading with a microaxial flow pump or to standard care during planned complex PCI. The primary outcome was a hierarchical composite that included death from any cause, disabling stroke, spontaneous myocardial infarction, hospitalization for cardiovascular causes, or periprocedural myocardial injury at a minimum of 12 months, as analyzed according to a win ratio. RESULTS: A total of 148 patients were assigned to receive a microaxial flow pump and 152 to receive standard care. At a median of 22 months (interquartile range, 16 to 30), 36.6% of pairwise comparisons favored the microaxial flow pump, and 43.0% favored standard care (win ratio, 0.85; 95% confidence interval CI, 0.63 to 1.15; difference, -6.4 percentage points; P = 0.30). Death from any cause occurred in 47 patients in the microaxial-flow-pump group and 33 in the standard-care group (hazard ratio, 1.54; 95% CI, 0.99 to 2.41). There was no material between-group difference in the risk of bleeding or vascular complications. CONCLUSIONS: Among patients with severely impaired left ventricular function undergoing complex PCI, elective left ventricular unloading with a microaxial flow pump did not reduce the risk of major adverse clinical outcomes at a minimum of 12 months. (Funded by the U.K. National Institute for Health and Care Research; CHIP-BCIS3 ClinicalTrials.gov number, NCT05003817.).

Expert Takes24 quotes

1/24

“The results were 'surprising because the whole premise of LV unloading was that it protects the heart.' But we found that patients assigned to LV unloading had more damage to the [LV] than those assigned to standard care. Our findings strongly suggest that we shouldn't be using this device routinely without more evidence of benefit.”

Divaka Perera, MD, Interventional Cardiologist, Trial Lead InvestigatorKing's College London, Guy's & St Thomas' HospitalconferenceView source

Consensus

+Strong agreement that routine elective LV unloading with a microaxial flow pump (Impella CP) does not improve the primary hierarchical composite endpoint or reduce major adverse events in patients with severe LV dysfunction (LVEF ~27%) undergoing complex high-risk PCI, as shown by the neutral win ratio (0.85, p=0.30) in CHIP-BCIS3 (moderate-to-strong agreement across editorial, discussants, and social commentary).
+Broad consensus that the trial provides sufficient evidence against routine 'protected PCI' with Impella in stabilized patients without hemodynamic instability or cardiogenic shock; selective use is preferred (echoed in NEJM editorial, Mehran, Kirtane, Perera, and Sperry).
+Agreement that procedural strategy matters: more complete revascularization during index procedure in the Impella arm did not translate to better outcomes and may have contributed to harm signals; staging PCI is likely preferable (noted by Kirtane, PCR coverage, and X discussions).

Open Questions

?Debate on the role of periprocedural MI in the primary composite endpoint, with some interventionalists (e.g., Salman Arain on X) questioning if it unfairly disadvantaged the Impella arm given potential device-related enzyme elevations (poll and thread discussion).
?Whether observed harm (higher CV death, HR 1.91) is directly due to the device (bleeding, vascular issues, hemolysis) versus behavioral changes in operators pursuing more aggressive revascularization under 'protection' (highlighted by Kirtane and Mehran as an open question).
?Degree of applicability: some note the trial population was very high-risk but not in shock, leaving room for individualized use in select unstable cases despite overall negative results (implicit in Sperry and Arain posts vs. stricter editorial stance).

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“24 expert quotes

Authors

D Perera

Matthew Ryan

Saad Ezad

Journals

New England Journal of Medicine

Actions

Institutions

King's College London

London School of Hygiene & Tropical Medicine

Guy's and St Thomas' NHS Foundation Trust

References and Citations

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Discussion

Cite this study

Perera et al. (Sun,) conducted a rct in Severe left ventricular dysfunction and extensive coronary artery disease (n=300). Elective unloading with a microaxial flow pump vs. Standard care was evaluated on Hierarchical composite of death from any cause, disabling stroke, spontaneous myocardial infarction, hospitalization for cardiovascular causes, or periprocedural myocardial injury at a minimum of 12 months (win ratio 0.85, 95% CI 0.63 to 1.15, p=0.30). Elective unloading with a microaxial flow pump during complex PCI did not improve the primary composite outcome compared to standard care (win ratio 0.85; 95% CI 0.63-1.15; P=0.30).

www.synapsesocial.com/papers/69ccb55116edfba7beb87411 — DOI: https://doi.org/10.1056/nejmoa2515704

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Left Ventricular Unloading in High-Risk Percutaneous Coronary Intervention

Expert Consensus

Open Questions

Key Result

Key Points

Study Design

Structured PICO

Abstract

Expert Takes24 quotes

Consensus

Open Questions

Citation Network

Connected Papers

Discussion

Social Feed

Expert Takes

Authors

Journals

Actions

Institutions

References and Citations

Citation Network

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Discussion

Cite this study

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