Impact of the angle between aortic and mitral annulus on the occurrence of hemolysis during Impella support.

: Despite optimal management, we sometimes experience refractory hemolysis requiring extensive device speed reduction or continuous hemodiafiltration following Impella implantation. However, pre-procedural predictors of such a refractory hemolysis remain unknown. In this study, we investigated the pre-procedural factors, including the echocardiographic narrow angle between aortic and mitral annulus, associating with the occurrence of refractory hemolysis following Impella insertion. We enrolled 26 patients (71 years, 65% male) who received Impella insertion between March 2018 and November 2019. Among baseline characteristics, the angle between aortic and mitral annulus, < 126.5°, was an independent risk factor of refractory hemolysis with an adjusted hazard ratio of 7.840 (95% confidence interval 0.925-66.44) and was associated with lower 30-day survival (64% vs. 100%, p = 0.0116). The narrow angle between aortic and mitral annulus might be a useful tool to risk-stratify the occurrence of refractory hemolysis following Impella insertion.