A prospective survey on incidence, risk factors and therapy of hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation.

BACKGROUND AND OBJECTIVES: Veno-occlusive disease (VOD) is one of the most frequent complications after stem cell transplantation. We conducted a prospective survey of 244 hematopoietic stem cell transplants in children to determine the incidence of VOD, its main risk factors, treatment and effect on the transplant.

DESIGN AND METHODS: Two hundred and forty-four hematopoietic stem cell transplants (HSCT) performed in 220 pediatric patients from 1993 to 2003 were evaluated. The series included 127 males and 93 females with a median age of 6.7 years at the time of transplantation.

RESULTS: VOD was diagnosed following 26 of the 244 transplants (cumulative incidence 11%), but a higher incidence was found in patients with at least one known risk factor for VOD (cumulative incidence 20%). In multivariate analysis, risk factors for VOD were age < 6.7 years; type of VOD prophylaxis, and busulphan-containing conditioning regimens. Routine treatment of VOD was based on supportive care and, starting from 1999, defibrotide was used. All patients were monitored with daily Doppler ultrasound-(US) for early diagnosis of inversion of portal blood flow. Twelve patients developed inversion of portal flow (9 had severe VOD; 3 had moderate VOD) and were promptly started on fibrinolytic and anticoagulant therapy with heparin and recombinant tissue plasminogen activator (rt-PA). Hepatic flow reverted to normal in all 12 patients; only 4 patients ultimately developed multiorgan failure and died. The transplant-related-mortality (TRM) rate in patients with or without inversion of portal flow was 33% vs 7%, (p=0.1). The TRM in patients with or without VOD was 19% vs 8% (p=0.001).

INTERPRETATION AND CONCLUSIONS: This study showed that younger age, type of VOD prophylaxis, and busulphan-based conditioning regimens are independent risk factors for VOD. Inversion of portal flow was found in 9 of 10 patients with severe VOD. Doppler US monitoring may be helpful in early identification of the patients with VOD-induced inversion of portal flow who might benefit from therapy with heparin and rt-PA.