Dunbar syndrome in liver transplantation: results of a single center matched-pair analysis and a European survey study

Question:

In Dunbar or median arcuate ligament syndrome (MAL), a low-lying ligament may lead to functional compression of the coeliac axis. As such, MAL potentially causes severe arterial complications in orthotopic liver transplantation (OLT). Here we aimed to investigate MAL incidence and its clinical impact after OLT. In addition, we performed an international survey study to investigate local protocols on the diagnosis, and treatment of MAL in OLT patients.

Methods:

Between 2010 – 2017 302 OLTs (w/o living donation, split, and re-OLT) were performed at our institution. MAL was diagnosed in 32 patients (10%). A matched-pair analysis (MAL n = 32 versus non-MAL n = 64; 1: 2 matching based on BAR-score, recipient age, transplant indication) was carried out comparing postoperative complications as assessed by the Clavien-Dindo (CD) score. Preoperative CT-scans were evaluated independently by two experienced staff radiologists for variant anatomy of the celiac trunk. Furthermore, an online-survey was sent to all Eurotransplant (n = 37), Swisstransplant (n = 3), Scandiatransplant (n = 5) and British Transplantation Society (n = 7) centers. The survey sought information on OLT case-load and the management of patients with MAL. Parametric and non-parametric tests were used for data analysis.

Results:

Recipient and donor baseline characteristics showed no significant differences. Cohen's Kappa confirmed good inter-observer agreement (k = 0.779) on the radiological diagnosis of MAL. Median BAR-Score was 11 (range 2 – 20) in the MAL and 10 (range 2 – 21) in the non-MAL group. In 55% of the cases extended criteria allografts have been used for OLT without between group differences. Early allograft dysfunction occurred in 40% in the MAL and 38% in the non-MAL groups (p = 0.767). Incidence of major postoperative and arterial complications were not significantly different between groups (>= CD 3 MAL: 63%; non-MAL: 59%). Ultimately, one-year graft and patient survival did not differ significantly between MAL and non-MAL patients. 81% of the 52 centers gave a valid response to our survey. The strategies regarding diagnostics and treatment of MAL were heterogeneous. Only 29% of the centers reported that they are routinely dividing the MAL in Dunbar patients during transplantation.

Conclusions:

The approach on diagnostics and treatment of MAL in OLT is heterogeneous in European centers. Our institutional strategy to always divide the MAL during transplantation in cases of Dunbar with clinical signs of stenosis, seems to provide a safe and feasible approach to avoid MAL related vascular complications in OLT. Larger studies are needed to validate our findings.

 

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