Pleuropulmonary pathologies in the early phase of acute pancreatitis correlate with disease severity

Abstract

Background: Respiratory failure worsens the outcome of acute pancreatitis (AP) and underlying factors might be early detectable.

Aims: To evaluate the prevalence and prognostic relevance of early pleuropulmonary pathologies and pre-existing chronic lung diseases (CLD) in AP patients.

Methods: Multicentre retrospective cohort study. Caudal sections of the thorax derived from abdominal contrast enhanced computed tomography (CECT) performed in the early phase of AP were assessed. Independent predictors of severe AP were identified by binary logistic regression analysis. A one-year survival analysis using Kaplan-Meier curves and log rank test was performed.

Results: 358 patients were analysed, finding pleuropulmonary pathologies in 81%. CECTs were performed with a median of 2 days (IQR 1-3) after admission. Multivariable analysis identified moderate to severe or bilateral pleural effusions (PEs) (OR = 4.16, 95%CI 2.05-8.45, p<0.001) and pre-existing CLD (OR = 2.93, 95%CI 1.17-7.32, p = 0.022) as independent predictors of severe AP. Log rank test showed a significantly worse one-year survival in patients with bilateral compared to unilateral PEs in a subgroup.

Conclusions: Increasing awareness of the prognostic impact of large and bilateral PEs and pre-existing CLD could facilitate the identification of patients at high risk for severe AP in the early phase and thus improve their prognosis.

Fig 1. Exemplary representation of CECT imaging (mediastinal window) with unilateral dystelectasis (green) and severe, bilateral pleural effusions (red).

Pleuropulmonary changes were analysed in the caudal sections of the thorax captured on the abdominal CECT (contrast enhanced computed tomography) scan. Thorax CECTs were additionally screened for pathologies, if available. The size of pleural effusions was determined in the transverse plane of the lung and mediastinal window. The area dorsal the midline of the thorax was divided into three parts similar in size (blue lines). Pleural effusions were classified as “low” if they remained dorsal line 2, as “moderate” if exceeding line 2, but not line 3 and as “severe” if exceeding line 3.

Fig 2. Distribution of early pleuropulmonary findings in CECT imaging from patients with acute pancreatitis (n = 358).

Proportions of all pleuropulmonary findings in the study population with subdivisions into the different grades of acute pancreatitis (AP) are depicted in (a). The median timing of CECT imaging was 2 days after admission. Graphs (b) and (c) show the detailed localisation and severity of pleural effusions (PEs) and (d) the distribution of dystelectases. In total, 81% (289/358) of patients had pleuropulmonary changes in CECT imaging and the occurrence mostly increased with severity of AP, e.g. approximately one-third of patients with mild AP showed PEs (52/147, 35%), whereas PEs appeared in 76% (35/46) in patients with severe AP. In most cases (273/358, 76%) the detected findings were dystelectases. More than 90% (247/273, 91%) of dystelectases appeared bilateral. Pleural enhancement was found in 12% (44/358) and an elevation of the left diaphragm in 10% (35/358). More than half of the patients had PE (195/358, 54%), that was mostly (150/195, 77%) bilateral. If unilateral, PE was observed particularly in the left pleural cavity (36/45, 80%). When PE was prevalent, its amount was classified as low, moderate or severe in 48% (94/195), 30% (59/195) and 22% (42/195) of the cases, respectively.

Fig 3. Bilateral pleural effusions in the early phase of acute pancreatitis are associated with worse one-year survival.

Kaplan–Meier curves of patients with none or unilateral pleural effusions (PEs) (n = 59) versus patients with bilateral PEs (n = 31) in the early phase (median 2 days after admission) of acute pancreatitis (AP) are shown. Survival data was only available for a subgroup of patients (study centre Halle, Germany, n = 90). Hospitalised patients with AP were followed up for one year after admission. Overall, 16 patients (18%) died during follow up. Of patients with none/ unilateral PEs 12% (7/59) died, whereas 29% (9/31) of the patients with bilateral PEs died. Log rank test showed significant worse one-year survival in the group of patients with bilateral PEs compared to none/ unilateral PEs (p = 0.04).