First-month renal function trajectories after left ventricular assist device (LVAD) implantation vary widely. Lack of renal function improvement (RFI) and postoperative acute kidney injury (AKI) are associated with increased mortality. This study evaluates plasma levels of endostatin and cystatin C as predictors of RFI and AKI 1 month post-LVAD implantation. We prospectively enrolled 52 advanced heart failure patients undergoing LVAD implantation. Blood samples were collected pre-implant and at 1, 2, 3, and 4 weeks post-implant. Plasma levels of endostatin and cystatin C were measured. Among 52 patients, 24 (46.2%) achieved RFI, whereas 28 (53.8%) did not. Of the non-RFI group, 15 (53.6%) developed AKI within the first month. Baseline endostatin was highly significant in predicting RFI (p = 0.012), followed by cystatin C (p = 0.045). The patients without RFI were considered high-risk patients for postoperative AKI. We noticed distinct trajectories for postoperative 1 week cystatin C value, not endostatin, between AKI and no-AKI patients. Postoperative 1 week level of cystatin C is identified as a good biomarker for postoperative AKI prediction in these high-risk group patients. Baseline endostatin levels can help identify patients with reduced renal adaptive capacity. For patients with high pre-implant plasma endostatin values, monitoring circulating postoperative 1 week cystatin C allows physicians to detect AKI early.