Predictive value of early postoperative hemodynamic parameters of Rex shunt graft for graft thrombosis in children with cavernous transformation of the portal vein.
Xiao L, Wang C, et al. • Pediatric surgery international • 2026
Serial monitoring of early mesenteric hemodynamic parameters of the Rex graft offers favorable predictive performance for graft thrombosis, with mesenteric velocity showing an AUC of 0.986 and an optimal cutoff value of 26 cm/min facilitating timely clinical intervention in children with cavernous transformation of the portal vein.
Key Findings
Results
Vascular complications occurred in 35.3% of children undergoing Rex shunt for cavernous transformation of the portal vein, with graft thrombosis accounting for nearly half of these complications.
34 children with CTPV underwent primary Rex shunt at Hunan Children's Hospital between May 2010 and November 2025.
12 patients (35.3%) experienced vascular complications: 5 graft thrombosis cases, 5 anastomotic stenosis cases, and 2 cases of graft compression by local edema.
The median postoperative follow-up duration was 40 months.
The median time to complication onset was 7 (2, 730) days.
Results
Hemodynamic parameters at the mesenteric graft end remained stable throughout the first postoperative week in patients without complications.
Patients were divided into a non-complication group (Group A, n=22) and a vascular complication group (Group B, n=12).
Hemodynamic parameters remained stable throughout the first postoperative week in Group A (all P > 0.05).
The mesenteric graft end with a mean flow velocity of 56.32 ± 19.51 cm/min and mean flow volume of 394.91 ± 225.83 mL/min was associated with maintained graft patency.
Serial ultrasonography was used to measure hemodynamic parameters at both ends of the graft.
Results
Mesenteric graft end flow velocity was a highly accurate predictor of graft thrombosis, with an AUC of 0.986 and an optimal cutoff of 26 cm/min.
ROC analysis showed the area under the curve (AUC) of mesenteric velocity was 0.986 (P < 0.001).
The optimal cutoff value for mesenteric velocity was 26 cm/min.
At this cutoff, specificity was 90.9% and sensitivity was 100%.
Markedly decreased velocity below this threshold indicated high thrombotic risk.
Results
Decreased mesenteric graft end flow velocity was identified as a hemodynamic indicator of high thrombotic risk in Rex shunt grafts.
While stable hemodynamic parameters were observed in Group A, markedly decreased velocity at the mesenteric graft end was associated with thrombosis risk in Group B.
The study used ROC curves to determine optimal predictive cutoff values for graft thrombosis.
Both flow velocity and flow volume were measured at the mesenteric graft end as hemodynamic parameters.
The retrospective analysis covered a 15-year period (May 2010 to November 2025).
What This Means
This research suggests that monitoring blood flow speed in the graft used during Rex shunt surgery — a procedure that corrects blocked portal veins in children — can reliably predict whether the graft will develop dangerous blood clots. The study followed 34 children over a median of 40 months and found that about one-third experienced vascular complications after surgery, including blood clots, narrowing of the vessel connections, or graft compression. By using ultrasound to repeatedly measure how fast blood flows through the graft in the first week after surgery, doctors could identify children at high risk for graft failure.
The key finding was that a blood flow velocity below 26 cm/min at the mesenteric (intestinal) end of the graft was a strong warning sign for clot formation. This threshold had 100% sensitivity (meaning it correctly identified all patients who developed thrombosis) and 90.9% specificity, with an area under the curve of 0.986 — indicating near-perfect predictive accuracy. Children without complications maintained stable, higher flow velocities averaging about 56 cm/min throughout the first postoperative week.
This research suggests that routine ultrasound monitoring of graft blood flow velocity in the days immediately following Rex shunt surgery could allow medical teams to detect problems early and intervene before a clot fully develops. This could be particularly valuable for pediatric surgical centers managing children with cavernous transformation of the portal vein, a condition where the main portal vein to the liver is blocked and replaced by a tangle of smaller vessels.
Xiao L, Wang C, Zhou M, Peng Y, Liu J. (2026). Predictive value of early postoperative hemodynamic parameters of Rex shunt graft for graft thrombosis in children with cavernous transformation of the portal vein.. Pediatric surgery international. https://doi.org/10.1007/s00383-026-06599-w