Mechanical circulatory support with microaxial flow pump for high-risk PCI: a comparative analysis in left main disease

Abstract Background Mechanical circulatory support (MCS) has emerged as a potential adjunct to improve outcomes in high-risk percutaneous coronary interventions (HR-PCI). However, data comparing MCS to standard-of-care (SOC) remain limited. Purpose This study aims to compare revascularization completeness and clinical outcomes of left main (LM) PCI performed with microaxial flow pump (mAFP) support versus a standard-of-care (SOC) approach in patients with reduced left ventricular ejection fraction (LVEF), using propensity score–adjusted analyses. Materials and Methods We conducted a retrospective comparative analysis between two multicenter registries. The SOC cohort was derived from the DELTA 2 Registry, including patients undergoing elective PCI for distal LM bifurcation disease with LVEF <40%. The mAFP cohort was derived from the IMP-IT Registry, encompassing patients with severe LM stenosis who underwent HR-PCI supported by a mAFP. The primary endpoint was completeness of revascularization, defined as treatment of all angiographically significant lesions. Secondary endpoints included in-hospital clinical and device-related outcomes and follow-up events. Propensity score adjustment accounted for baseline differences. Results A total of 253 patients were included in the analysis, 171 in the SOC and 82 in the mAFP cohort. Baseline demographic and clinical characteristics were broadly comparable between groups (Table 1), whereas patients in the mAFP cohort presented a more complex coronary anatomy, with a higher prevalence of three-vessel disease and a higher median number of diseased vessels (Table 2) Nevertheless, mAFP-supported patients underwent more extensive revascularization, reflected by a greater number of implanted stents and increased use of calcium modification techniques (Table 2). Despite this higher complexity, the mAFP group showed a significantly higher rate of complete revascularization compared with SOC (45.6% vs. 23.9%; OR 2.28, 95% CI 1.30–3.97, p=0.004), a difference that remained significant after propensity adjustment (adjusted OR 2.38, 95% CI 1.33–4.26, p=0.006). In-hospital outcomes were similar between groups, indicating the procedural safety of mAFP-supported HR-PCI. During a median follow-up of 415 days, rates of all-cause death did not differ significantly between mAFP and SOC groups (HR 0.86, 95% CI 0.4–1.8, p=0.716). However, myocardial infarction occurred more frequently among mAFP-treated patients (HR 6.0, 95% CI 1.1 vs 31.9%, p= 0.034) Conclusions In this comparative multicenter analysis, the mAFP group showed a significantly higher likelihood of achieving complete revascularization, despite greater anatomical and procedural complexity in LM-HRPCI. Further prospective studies are warranted to evaluate long-term clinical benefits and refine patient selection for protected PCI strategies.For image description, please refer to the figure legend and surrounding text. For image description, please refer to the figure legend and surrounding text.