A Second Look: Retrospective Identification of Thrombotic Microangiopathy in Pediatric Stem Cell Transplant Patients With Veno‐Occlusive Disease

Abstract

Background: Veno-occlusive disease (VOD) and transplant-associated thrombotic microangiopathy (TA-TMA) remain a diagnostic and therapeutic challenge for patients undergoing hematopoietic stem cell transplant (HSCT). Both VOD and TA-TMA share an underlying etiology of microvascular endothelial damage. Potential under-recognition of TA-TMA in the context of VOD leaves HSCT recipients vulnerable to additional endothelial damage, and risk of end-organ failure. Methods: A cohort of 44 pediatric HSCT recipients diagnosed with VOD between 2010and 2019 were retrospectively evaluated for the development of TA-TMA within 1 week before and 2 months after VOD diagnosis. Patients were classified into three categories: sole diagnosis of VOD (VOD), concurrent clinical diagnosis of TA-TMA during the VOD course (VOD+TA-TMA), and patients with VOD who on retrospective review satisfied criteria for diagnosis of TA-TMA (VOD+rTA-TMA). Results: A total of 42 patients were evaluated and 50% of the patients were diagnosed clinically with TA-TMA (5) or where retrospectively identified to have TA-TMA (16). There was no difference in the severity of the course of VOD between the three groups based on need for intubation, dialysis, and pediatric intensive care unit (PICU) care. Patients in the VOD only group had the highest survival at 1 year (66.7%, n = 14) compared with patients in the VOD+TA-TMA group (60%, n = 3) and VOD+rTA-TMA group (62.5%, n = 10), p = 0.9582. Conclusion: Better understanding of the association between these two endotheliopathies is essential to improve diagnosis, treatment, and prevention of potentially fatal adverse outcomes in transplant recipients.