Higher Cryopreserved CD34+ Cell Dose Is Associated with Decreased Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome after Single-Unit Cord Blood Transplantation in Adults Given Prophylactic Ursodeoxycholic Acid and Intravenous Heparin.

Hepatic veno-occlusive disease (VOD), also known as sinusoidal obstruction syndrome (SOS), is one of the most serious complications to occur early after allogeneic hematopoietic cell transplantation (HCT). However, detailed data on VOD/SOS after cord blood transplantation (CBT) are not available. The objective of this retrospective study was to evaluate the incidence, risk factors, and clinical impact of VOD/SOS after single-unit unrelated CBT for adult patients at our institution. We retrospectively evaluated the incidence, risk factors, and outcomes of VOD/SOS after 390 single-unit unrelated CBTs performed in 332 adults under a prophylactic strategy of ursodeoxycholic acid (UDCA) and i.v. heparin at our institution between 1998 and 2021. VOD/SOS was observed in 24 of the 390 CBTs. The cumulative incidence of VOD/SOS was 5.9% at 30 days and 6.2% at 100 days after CBT. Multivariate analysis showed that cryopreserved CD34+ cell dose ≥1.0 × 105/kg was significantly associated with a decreased risk of VOD/SOS after CBT (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.12 to 0.91; P = .032). In multivariate analysis, the development of VOD/SOS was significantly associated with higher overall mortality (HR, 6.19; 95% CI, 3.61 to 10.65; P < .001), treatment failure (HR, 4.79; 95% CI, 2.95 to 7.76; P < .001), and nonrelapse mortality (HR, 12.60; 95% CI, 6.90 to 23.00; P < .001). Our study shows that the incidence of hepatic VOD/SOS was relatively low after unrelated single-unit CBT under a prophylactic strategy of UDCA and i.v. heparin. A higher cryopreserved cord blood CD34+ cell dose was associated with a reduction in VOD/SOS, suggesting that selection of a higher cord blood unit CD34+ cell dose could be efficient in preventing hepatic VOD/SOS in adults undergoing single-unit CBT.