Active malignancy modifies the association between temporary mechanical circulatory support and in-hospital mortality in high-risk percutaneous coronary intervention

Background Temporary mechanical circulatory support (tMCS) is frequently used during high-risk percutaneous coronary intervention (HR-PCI), yet outcomes in patients with active malignancy remain poorly characterised. Purpose To determine whether active malignancy modifies the association between tMCS use and in-hospital mortality in HR-PCI. Methods We performed a retrospective cohort study of PCI admissions in a large single-centre critical care database, the Medical Information Mart for Intensive Care IV (MIMIC-IV). HR-PCI was defined by early markers of haemodynamic instability or end-organ dysfunction within 48 hours of admission, including cardiogenic shock, vasopressor use, elevated lactate, acute kidney injury, or intensive care unit admission. Active malignancy was identified using diagnosis codes from the index hospitalisation, excluding non-melanoma skin cancers. Multivariable logistic regression with cluster-robust standard errors assessed in-hospital mortality, including an interaction term between malignancy and tMCS use. Adjusted predicted mortality was estimated across malignancy and tMCS strata. Results Among 2,867 HR-PCI admissions, 163 (5.7%) had active malignancy and 172 (6.0%) received tMCS. Active malignancy significantly modified the association between tMCS use and mortality (interaction OR 13.4, 95% CI 2.0–91.4; p=0.008). Model-predicted mortality was low among patients without malignancy regardless of tMCS use (0.8% without tMCS vs 0.9% with tMCS) and modest among patients with malignancy not receiving tMCS (1.5%), but markedly higher among those with both malignancy and tMCS (17.6%). Although the confidence interval for this subgroup was wide owing to small numbers of patients with malignancy receiving tMCS, the interaction remained statistically significant, supporting consistent effect modification rather than imprecision alone. Conclusion In HR-PCI, active malignancy identifies a distinct high-risk phenotype in which tMCS use is associated with substantially higher in-hospital mortality, highlighting the need for malignancy-informed risk stratification and prospective studies to guide mechanical support decision-making in patients with active cancer.