Association between lymphatic abnormalities in the neck and thorax in primary chylopericardium and surgical outcomes evaluated by non-enhanced magnetic resonance (MR) lymphangiography.

Background: Chylopericardium refers to the accumulation of chylous fluid in the pericardial cavity. Non-enhanced magnetic resonance lymphangiography (MRL) can show neck and thoracic lymphatic abnormalities in the primary chylopericardium. It is not clear whether there is a relationship between neck and thoracic lymphatic abnormalities in primary chylopericardium and thoracic duct terminal release surgery. This study aimed to explore the correlation between the severity of neck and thoracic lymphatic abnormalities observed in non-enhanced MRL and the surgical outcomes in primary chylopericardium.

Methods: This is a retrospective cohort study. A retrospective analysis was conducted on fifty-six patients diagnosed with primary chylopericardium between January 2016 and December 2021, all of whom underwent thoracic duct terminal release surgery. Ultrasonography, chest computed tomography (CT) and non-enhanced MRL were performed prior to the surgical intervention. Patients were categorized into four types based on the severity of neck and thoracic lymphatic abnormalities observed in the non-enhanced MRL. Clinical and laboratory examinations and surgical outcomes were compared across different types using χ ²-test or Fisher's exact test, t-test, and Kruskal-Wallis H-test. Additionally, independent factors influencing surgical outcomes were analyzed.

Results: Among primary chylopericardium cases (n=56), 22 (39.2%) were classified as type I or II, 17 (30.4%) as type III, and 17 (30.4%) as type IV. Surgical outcomes were more favorable for type I or II patients than those with type III or IV, accompanied by a reduction in postoperative primary chylopericardium volume (P=0.002). Postoperative chest CT scans indicated that type I or II patients had fewer instances of large grid shadows, small grid shadows, and bronchovascular bundle thickening compared to preoperative scans (P=0.001, P=0.02, P=0.03). Age and bronchomediastinal trunk dilation emerged as independent factors influencing surgical outcomes [odds ratio (OR) 0.03, 95% confidence interval (CI): 0.003-0.220, P=0.001; OR 11.10, 95% CI: 1.70-72.39, P=0.01, respectively].

Conclusions: A more severe degree of neck and thoracic lymphatic abnormalities is associated with worse surgical outcomes. Moreover, age and bronchomediastinal trunk dilatation are independent predictors of surgical outcomes. Preoperative utilization of non-enhanced MRL for severity of lymphatic abnormalities classification in primary chylopericardium patients offers a noninvasive means of assessing surgical risk.