Key Points:
- In the original CHIP-BCIS3 study, microaxial flow pump use during complex PCI in patients with reduced ejection fraction was not associated with any change in major adverse cardiac events; however, there was an observed increase in cardiovascular (CV) mortality as well as a trend towards increased myocardial injury.
- It remains unknown whether periprocedural myocardial injury is associated with CV death, as well as whether myocardial injury may mediate the relationship between flow pump use and CV death.
- In this follow-up study, periprocedural myocardial injury was associated with increased CV death, but the association between flow pump use and CV death at two years was only partially (13%) mediated by myocardial injury itself.
Microaxial flow pump use has been proposed as a way to mitigate myocardial insult during complex PCI. In the original CHIP-BCIS3 study, published in NEJM in March 2026, pump use during complex PCI was not associated with any difference in major adverse cardiovascular events (MACE) at one year; however, in secondary analyses, there was a significant increase in cardiovascular death associated with pump use during that time period, as well as a nonsignificant increase in periprocedural myocardial injury. It remains unclear whether this increase in myocardial injury was associated with increased CV death during the index PCI itself, or whether the observed long-term increase in CV death was mediated by periprocedural myocardial injury. In a late-breaking presentation at the 2026 American Heart Association Scientific Sessions today, Dr. Aish Sinha and his team presented their study, “Procedure-related Myocardial Injury, Microaxial Flow Pump Use and Cardiovascular Death After Complex Percutaneous Coronary Intervention,” to address these questions.
CHIP-BCIS3 (NCT05003817) was a multi-center trial conducted across 21 sites in the UK that randomized 300 adults scheduled for complex PCI (median LVEF 27% and SYNTAX score 38) to microaxial flow pump placement vs standard PCI. Of planned procedures, 72% were left main-stem PCI and 27% involved planned PCI for chronic total occlusions. In the original study, patients were required to have an EF ≤35% (or ≤45% with severe mitral regurgitation); relevant exclusions were cardiogenic shock, STEMI, and contraindications to mechanical support. For this analysis, 133 microaxial flow pump patients and 124 standard of care patients were included, with 42 patients excluded due to lack of availability of periprocedural MI status. The primary analysis was the association between periprocedural myocardial injury and CV death. Secondary analyses included the association of microaxial flow pump use with procedural injury, as well as the proportion of CV death mediated by periprocedural injury during pump use.
Periprocedural myocardial injury was significantly associated with CV death (adjusted HR 2.55, 95% CI 1.29-5.02; P=0.007); each doubling of troponin was associated with a 15% higher adjusted hazard of cardiovascular death (adjusted HR of 1.15; 95% CI 1.02-1.29; P=0.018). Flow pump use corresponded with a 60.2% rate of myocardial injury compared to 49.2% in the standard arm, with flow pump randomization associated with a trend towards increased injury (adjusted RR 1.25, 95% CI 1.00-1.57; P=0.054). Finally, an estimated 13% of CV death at 24 months was mediated by procedure-related myocardial injury.
“Procedure-related myocardial injury was associated with CV death in patients undergoing complex PCI,” said Sinha. “Microaxial flow pump use was associated with a higher risk of CV death, which was only partially mediated by myocardial injury.”