Diagnosing and Grading of Sinusoidal Obstructive Syndrome after Hematopoietic Stem Cell Transplant of Children, Adolescent and Young Adults treated in a Pediatric Institution with Pediatric Protocols

Introduction Sinusoidal obstructive syndrome (SOS), or veno-occlusive disease (VOD), of the liver has been recognized as a complex, life-threatening complication in the post-hematopoietic stem cell transplant (HSCT) setting. The diagnostic criteria for SOS have evolved over the last several decades with a greater understanding of the underlying pathophysiology, with two recent diagnostic criteria introduced in 2018 (EBMT criteria) and 2020 (Cairo criteria). Objective We sought out to evaluate the performance characteristics in diagnosing and grading SOS in pediatric patients of the four different diagnostic criteria (Baltimore, Modified Seattle, EBMT, and Cairo) and severity grading systems (defined by the EBMT and Cairo criteria). Study Design: Retrospective chart review of children, adolescent and young adults (CAYA) who underwent conditioned autologous and allogeneic HSCT between 2017 and 2021 at a single pediatric institution. Results A total of 250 consecutive patients underwent at least one HSCT at UCSF Benioff Children's Hospital San Francisco for a total of 307 HSCT. The day 100 cumulative incidence of SOS was 12.1%, 21.1%, 28.4%, and 28.4% per the Baltimore, Modified Seattle, EBMT, and Cairo criteria, respectively (p<0.001). We found that patients diagnosed with grade ≥4 SOS per the Cairo criteria were more likely to be admitted to the PICU (92% vs. 58%, p=0.035) and intubated (85% vs. 32%, p=0.002) than those diagnosed with grade ≥4 per EBMT criteria. Age <3 years-old (HR 1.76, 95% [1.04-2.98], p=0.036), an abnormal BMI (HR 1.69, 95% [1.06-2.68], p=0.027), and high-risk patients per our institutional guidelines (HR 1.68, 95% [1.02-2.76], p=0.041) were significantly associated with SOS per the Cairo criteria. Conclusions We demonstrate that age <3 years, abnormal BMI, and other high-risk criteria associate strongly with subsequent SOS development. Patients with moderate to severe SOS based on Cairo severity grading criteria may correlate better with clinical course based on ICU admissions and intubations when compared to the EBMT severity grading system.