Analysis of risk factors and prognostic differences in hospital-acquired thrombosis between very preterm infants and moderate to late preterm infants.

内容摘要

Neonates have the highest incidence of thrombosis among pediatric populations, and preterm infants are at a high risk of venous thrombosis, with its risk factors remaining inconclusive and treatment criteria remaining ununified. This study aimed to explore the high-risk factors for venous thrombosis in preterm infants with varying gestational ages and catheterisation types, and to clarify the clinical characteristics, treatment strategies, and short-term prognosis of neonatal venous thrombosis, to provide evidence for clinical decision-making. A retrospective cohort study was conducted on 282 preterm infants admitted to the Neonatal Intensive Care Unit of Peking University Third Hospital from January 2014 to December 2025, including 94 cases in the thrombosis group and 188 cases in the control group. Clinical data, including maternal prenatal information, infant basic information, diagnosis and treatment course, catheter-related information, and thrombosis-related details, were collected from the electronic medical record system. SPSS 27.0 software was used for statistical analysis using the Kruskal-Wallis test, Student's t-test and Mann-Whitney U test for continuous variables; chi-square test or Fisher's exact test for categorical variables; and univariate and multivariate logistic regression models and Firth's penalised likelihood logistic regression analyses were applied to identify independent risk factors for venous thrombosis in preterm infants. The incidence of venous thrombosis was 0.45% in all hospitalised neonates and 1.0% in hospitalised preterm infants, with no significant differences in baseline data such as gestational age and birth weight between the two groups (P&#x2009;>&#x2009;0.05). Multivariate logistic regression analysis showed that right- and left-sided lower extremity PICC placement were independent risk factors for venous thrombosis in all preterm infants (P&#x2009;=&#x2009;0.000 and 0.007, respectively). Maternal anticoagulant or antiplatelet agents use during pregnancy was a clinical predictor(P&#x2009;=&#x2009;0.046). Stratified analysis by gestational age revealed that right lower extremity PICC placement(P&#x2009;=&#x2009;0.000) was an independent risk factor for very preterm infants (gestational age <32 0/7 weeks), and PICC placement (P&#x2009;<&#x2009;0.001) was also an independent risk factor for moderate-to-late preterm infants (32 0/7 weeks &#x2264; gestational age <37 0/7 weeks). Among all thrombotic groups, 96%(90/94) were associated with central venous catheterisation, including 22 cases of portal vein thrombosis (related to umbilical venous catheterisation) and 68 cases of extremity venous thrombosis (related to PICC placement). The median time from catheterisation to thrombosis was 5 (3.8, 8.0) days, with 59% were deep vein thrombosis and 59% were occlusive thrombosis. Only 34% of infants had clinical manifestations, and the detection rate of asymptomatic thrombosis increased with routine vascular ultrasound application. A total of 40% of patients received pharmacotherapy (mainly nadroparin calcium, supplemented with rt-PA), with 5% discontinuing medication due to active bleeding. For central venous catheters that were no longer in use, superficial vein thrombosis was managed by immediate catheter removal without anticoagulation. For deep vein thrombosis, anticoagulation was administered for at least 3 days, followed by catheter removal after follow-up imaging confirmed thrombus resolution or stabilisation. No thromboembolic events occurred during this process. After treatment, 98% of infants improved and were discharged; 65% of thrombi completely resolved, and 21% reduced in size before discharge, with a median resolution/reduction time of 17 (7, 31) days, and no extremity functional impairment was observed in any case. Compared with the PICC-related thrombosis group, the UVC-related thrombosis group was characterised by significantly higher birth weight (P&#x2009;=&#x2009;0.010), a shorter interval between catheter placement and thrombosis (4.0 vs. 6.0, P&#x2009;=&#x2009;0.019), and a shorter duration of hospitalisation (32.5 vs. 53.9, P&#x2009;=&#x2009;0.003). Lower extremity PICC placement is a core independent risk factor for venous thrombosis in preterm infants, with maternal anticoagulant use during pregnancy perhaps being a clinical predictor for all preterm infants. Neonatal venous thrombosis is mostly catheter-related, with a high proportion of asymptomatic cases, and routine vascular ultrasound can improve its detection rate. Individualised pharmacotherapy based on clinical manifestations and thrombus characteristics is associated with a favourable short-term prognosis, and timely adjustment of an abnormal catheter position is crucial for reducing thrombosis risk. Long-term follow-up is still needed for preterm infants with venous thrombosis to monitor for late adverse outcomes.