Use of Impella device in cardiogenic shock and its clinical outcomes: A systematic review and meta-analysis

Introduction: Cardiogenic shock (CS) is a life-threatening condition and mechanical circulatory support (MCS) might exert a relevant impact on its clinical course. Among MCS devices, Impella is very promising. Yet, its usefulness is still debated. We performed a meta-analysis of all studies evaluating the clinical impact of Impella in CS. Methods: All studies including patients with CS and treated with Impella were included. The primary endpoint was short-term mortality. Secondary endpoints were vascular access complications and major bleeding. Data synthesis was obtained using random-effects metanalysis. Results: Thirty-three studies and 5204 patients were included. Short-term mortality was 47%. Meta-regression analysis showed that patients age (p = 0.01), higher support level (p = 0.004) and pre-PCI insertion (p < 0.001) were significant moderators for the primary endpoint. Vascular access complications were registered in 6.4% of cases, whereas age (p = 0.05) and diabetes (p = 0.007) were significant predictors. Major bleeding occurred in 16.4% of patients. Meta-analysis of the subgroup of studies comparing Impella to IABP showed no significant difference in short-term mortality (RR = 1.08, p = 0.45), while rates of vascular access complications (p < 0.001) or major bleeding (p < 0.001) were significantly higher with Impella. Subgroup and metaregression analyses showed that these results were influenced by lower adoption rates of higher degree of MCS support (p = 0.003), and by higher vascular complications rates (p = 0.014). Conclusions: Our results suggest that the choice of adequate device size, careful patients selection and optimal timing of MCS initiation are key to clinical success with Impella in CS. Large prospective studies are mandatory to confirm these results deriving from retrospective studies.