Utility of Serial LVOT VTI as a Surrogate for Myocardial Performance During Weaning from Temporary Mechanical Circulatory Support in Cardiogenic Shock: A Retrospective Analysis

Background Despite ongoing research, robust evidence-based recommendations for daily echocardiographic evaluation to guide the weaning process in patients supported by temporary mechanical circulatory support devices (tMCS) such the Impella or intra-aortic balloon pumps (IABP), are lacking. We propose that protocolized bedside echocardiographic evaluation using left ventricular outflow tract velocity time integral (LVOT VTI) provides a reliable surrogate for myocardial performance before explant. Methods This single-center retrospective observational analysis examined patients admitted for cardiogenic shock (CS) requiring tMCS (Impella CP/5.0 and/or IABP) in the cardiac ICU at Baystate Medical Center between 2014 and 2017. A total of 23 patients contributed to 80 LVOT VTI measures and corresponding cardiac index (CI) values spanning the implant-explant period. We plotted three correlation graphs: the first between raw LVOT VTI and CI; the second between indexed LVOT VTI (iVTI, adjusted for body surface area) and CI; and the third between relative LVOT VTI (rVTI) and relative CI (rCI) compared to their initial post-implant values, providing a more accurate evaluation. Results The tests demonstrated a strong positive correlation among the variables, with correlation coefficients of r = 0.61, 0.59, and 0.74 for the graphs representing LVOT VTI/CI, iVTI/CI, and rVTI/rCI, respectively. Conclusion Our data supports the routine evaluation of LVOT VTI as a surrogate for myocardial performance in CS cases requiring prolonged mechanical unloading. This approach should be further developed and standardized for daily assessment during weaning in shock centers. Further research is needed to establish specific cut-offs associated with long-term myocardial recovery or remission.