What happened
Elective LV unloading shows no benefit for major outcomes at 12 months in complex PCI.
All three experts converge on the same bottom line: routine use of LV unloading during high-risk PCI cannot be recommended. The trial investigator found no evidence the pump protected the heart, while outside commentators independently called for a more selective approach.
Experts read CHIP-BCIS3 as a clear signal against routine Impella use during high-risk PCI, with the trial's principal investigator and outside commentators agreeing the strategy showed no benefit and possible harm.
The reaction is uniformly negative: no expert defends routine LV unloading for complex PCI in patients with severe LV dysfunction, and the trial investigator himself called the results surprising. Commentators are urging a more selective approach, reserving mechanical support for hemodynamic instability rather than elective use. The live question is whether any subgroup of stable high-risk PCI patients might still benefit, or whether protected PCI outside of cardiogenic shock should be largely abandoned.
Whether a subset of patients with clear hemodynamic instability or specific anatomic features might still benefit from mechanical support during PCI remains unanswered.
It is also unclear how these findings will affect existing guidelines and registry-driven practice patterns, given that most current Impella use occurs outside of cardiogenic shock.
“This was 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.”
News Coverage ↗From published coverage, not an answer posted here.
Roxana Mehran
Practice takeInterventional cardiologist, Icahn School of Medicine at Mount SinaiNo benefit and possibly harm, so routine use cannot be recommended
Original post ↗Brahmajee K. Nallamothu
Practice takeCardiologist, University of MichiganData support a more selective approach, reserving support for hemodynamic instability
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Why the trial, key points, tables, limitations, PICO, abstract, media & sources
Why the trial?
The CHIP-BCIS3 trial was conducted to address whether elective percutaneous left ventricular unloading with a microaxial flow pump improves outcomes in patients with severely impaired left ventricular function undergoing complex PCI, as this remains unclear.
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?
RCT (n=300)
1:1 ratio
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?
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Expert reaction
NEJM · ACC Annual Scientific Session 2025
Expert labels are toward CHIP-BCIS3's result, from named public quotes (n=0). As of Oct 20, 2026.
Experts read CHIP-BCIS3 as a clear signal against routine Impella use during high-risk PCI, with the trial's principal investigator and outside commentators agreeing the strategy showed no benefit and possible harm.
The reaction is uniformly negative: no expert defends routine LV unloading for complex PCI in patients with severe LV dysfunction, and the trial investigator himself called the results surprising. Commentators are urging a more selective approach, reserving mechanical support for hemodynamic instability rather than elective use. The live question is whether any subgroup of stable high-risk PCI patients might still benefit, or whether protected PCI outside of cardiogenic shock should be largely abandoned.
All three experts converge on the same bottom line: routine use of LV unloading during high-risk PCI cannot be recommended. The trial investigator found no evidence the pump protected the heart, while outside commentators independently called for a more selective approach.
Whether a subset of patients with clear hemodynamic instability or specific anatomic features might still benefit from mechanical support during PCI remains unanswered. It is also unclear how these findings will affect existing guidelines and registry-driven practice patterns, given that most current Impella use occurs outside of cardiogenic shock.
As the trial's principal investigator, Perera said the results were surprising because the entire premise of LV unloading was cardiac protection, yet the pump group had more LV damage. He noted that more than 75% of Impella implants in registries have been for high-risk PCI rather than shock, and said these results should prompt reconsideration of routine use.
Mehran concluded that CHIP-BCIS3 shows no benefit and possible harm from routine LV unloading during complex PCI. She stated plainly that the strategy cannot be recommended.
Nallamothu argued that the trial provides sufficient data to encourage a more selective use of mechanical circulatory support in high-risk PCI, particularly when there is no clear hemodynamic instability.
Elective left ventricular unloading with a microaxial flow pump during complex PCI in patients with severe LV dysfunction did not reduce major adverse clinical outcomes compared to standard care.
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.).
Perera et al. (2026) conducted an 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 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 (win ratio 0.85, 95% CI 0.63-1.15, p=0.30). Elective left ventricular unloading with a microaxial flow pump during complex PCI did not improve major adverse clinical outcomes versus standard care (win ratio 0.85; 95% CI 0.63-1.15; P=0.30).
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