Weekly Journal Scan: Reassessing the promises and challenges of routine left ventricular support during high-risk percutaneous coronary intervention

This comment refers to ‘Left Ventricular Unloading in High-Risk Percutaneous Coronary Intervention’, which was published in the New England Journal of Medicine, https://doi.org/10.1056/NEJMoa2515704. Patients with severe LV dysfunction undergoing complex and high-risk PCI represent one of the most challenging populations in contemporary interventional cardiology.2 Extensive CAD, limited myocardial reserve, and the risk of transient ischaemia during prolonged and technically demanding procedures have provided a compelling rationale for the use of temporary mechanical circulatory support.2 Among available devices, microaxial flow pump has been increasingly adopted to maintain systemic perfusion and unload the LV, with the expectation that improved haemodynamic stability would facilitate more complete revascularization and ultimately translate into LV functional recovery3 and better clinical outcomes.4 The randomized PROTECT II trial, which compared a microaxial flow pump with intra-aortic balloon pump support during high-risk PCI, did not show significant differences in major adverse events at 30 days between the two groups and was terminated early for futility, although a trend towards improved outcomes with microaxial flow pump was observed at a pre-specified 90-day follow-up.5 In the prospective, multicentre, single-arm, observational, FDA-audited post-approval PROTECT III study,6 microaxial flow pump-supported high-risk PCI was associated with more complete revascularization, less bleeding, and improved 90-day clinical outcomes compared to a PROTECT II historical cohort. Likewise, a subanalysis of the IMP-IT registry demonstrated an association between the extent of revascularization achieved during microaxial flow pump-supported PCI and subsequent survival, reinforcing the hypothesis that LV support may derive its benefit by facilitating more complete coronary revascularization.7 However, these data must be interpreted in the context of the neutral findings of REVIVED-BCIS2, where PCI itself failed to reduce death or heart failure hospitalization in patients with severe ischaemic LV dysfunction, independent of the extent of revascularization.8 Of note, mechanical circulatory support was used in only 3% of patients randomized to PCI. Reflecting these uncertainties, the 2024 European Society of Cardiology Guidelines for the management of chronic coronary syndromes assign a class IIb recommendation to the use of microaxial flow pump in carefully selected patients undergoing high-risk PCI in experienced centres.9