Background: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly used to treat cardiogenic shock. However, VA-ECMO might hamper myocardial recovery. The Impella unloads the left ventricle. The aim of this study was to evaluate if left ventricular unloading in cardiogenic shock patients treated with VA-ECMO was associated with lower mortality. Methods: Data from 686 consecutive patients with cardiogenic shock treated with VA-ECMO with or without left ventricular unloading (using an Impella) at 16 tertiary-care centers in 4 countries were collected. The association between left ventricular unloading and 30-day mortality was assessed by Cox regression models in a 1:1 propensity-score-matched cohort. Results: Left ventricular unloading was used in 337 of the 686 patients (49%). After matching, 255 patients with left ventricular unloading were compared with 255 patients without left ventricular unloading. In the matched cohort, left ventricular unloading was associated with lower 30-day mortality (hazard ratio 0.79, 95% confidence interval 0.63-0.98, p=0.03) without differences in various subgroups. Complications occurred more frequently in patients with left ventricular unloading; e.g. severe bleeding in 98 (38.4%) vs. 45 (17.9%), access-site related ischemia in 55 (21.6%) vs. 31 (12.3%), abdominal compartment in 23 (9.4%) vs. 9 (3.7%) and renal replacement therapy in 148 (58.5%) vs. 99 (39.1%). Conclusions: In this international, multicenter cohort study, left ventricular unloading was associated with lower mortality in cardiogenic shock patients treated with VA-ECMO, despite higher complication rates. These findings support use of left ventricular unloading in cardiogenic shock patients treated with VA-ECMO and call for further validation, ideally in a randomized, controlled trial.

Recognition of cell death by the innate immune system triggers inflammatory responses. However, how these reactions are regulated is not well understood. Here, we identify the inhibitory C-type lectin receptor Clec12a as a specific receptor for dead cells. Both human and mouse Clec12a could physically sense uric acid crystals (monosodium urate, MSU), which are key danger signals for cell-death-induced immunity. Clec12a inhibited inflammatory responses to MSU in vitro, and Clec12a-deficient mice exhibited hyperinflammatory responses after being challenged with MSU or necrotic cells and after radiation-induced thymocyte killing in vivo. Thus, we identified a negative regulatory MSU receptor that controls noninfectious inflammation in response to cell death that has implications for autoimmunity and inflammatory disease.

This study uses genetic and pharmacologic approaches to demonstrate novel roles of eosinophils in the progression of atherosclerosis and arterial thrombosis.

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