岩見 大基

INTRODUCTION: This study aimed to develop a limited sampling strategy (LSS) and predictive equations to accurately estimate the areas under the concentration-time curves (AUC) of extended-release tacrolimus (TAC-ER) and mycophenolic acid (MPA). METHODS: A retrospective analysis of Japanese kidney transplant recipients yielded 90 TAC-ER AUC0-24 (23 patients) and 80 MPA AUC0-12 (29 patients) datasets, which were randomly split into learning and validation datasets. Training datasets were used to generate the LSS model equations based on multiple linear regression analysis, and the coefficient of determination (R2) was used to assess the goodness of fit of regression models. Validation datasets applied the selected training equations to compute error indices, Passing-Bablok's Kendall's τ, and Bland-Altman limits of agreement, thereby assessing predictive bias, accuracy, and precision. RESULTS AND DISCUSSION: Four equations (C0-C1-C6, C0-C1-C2-C6, C0-C1-C3-C6, C0-C1-C4-C6) showed strong correlations with the actual AUC (R² > 0.95), with the validation identifying C0-C1-C3-C6 as the most reliable for both TAC-ER and MPA. This study demonstrated that LSS using C0-C1-C3-C6 reliably and accurately estimated both the actual TAC-ER AUC0-24 and MPA AUC0-12 simultaneously in kidney transplant recipients. These equations can be feasibly implemented in outpatient clinical settings to reduce time and cost.

INTRODUCTION: Priapism is a persistent penile erection lasting > 4 h without sexual stimulation. Ischemic priapism requires urgent management. We report a recurrent ischemic priapism case post-living-donor kidney transplantation necessitating multiple interventions, including bilateral T-shunt procedures. CASE PRESENTATION: A 44-year-old man with end-stage kidney disease from malignant nephrosclerosis and IgA nephropathy underwent living-donor kidney transplantation. On postoperative Day 5, priapism appeared upon catheter removal. Bedside corporal aspiration was initially performed. Recurrence prompted Winter's shunt on Day 6. Blood gas analysis confirmed ischemic priapism. On Day 7, further recurrence required bilateral T-shunts, resolving the condition. Propofol, used during anesthesia, was suspected as the cause. At the 6-month follow-up, priapism had not recurred, though erectile dysfunction developed. CONCLUSION: This case highlights a rare but serious complication of kidney transplantation under general anesthesia, potentially linked to propofol. Timely escalation from aspiration to surgical shunting is crucial in persistent cases to prevent long-term sequelae.