Hemodynamic Instability after Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension Correlates with Cytokine Network Hyperstimulation

Background: Pulmonary endarterectomy (PEA) is an effective treatment for chronic thromboembolic pulmonary hypertension (CTEPH). The present study tested the hypothesis that inflammation, as determined by circulating cytokine levels, may contribute to the difficulty in controlling arterial blood pressure after PEA. Materials and Methods: Thirty-six patients with CTEPH (22 males and 14 females) underwent PEA using cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest. Plasma concentrations of tumor necrosis factor α, interleukin (IL)-1β, IL-6 and IL-8 were measured repeatedly in arterial blood samples. Results: A significant correlation between norepinephrine support and IL-6 plasma concentrations was shown at the separation from CPB (k = 0.742) and 12 h after it (k = 0.801) as well as between norepinephrine support and IL-8 concentrations 12 h after the separation from CPB. Furthermore, a significant correlation was found between the cardiac index (CI) and both IL-6 and IL-8 at the separation from CPB. Conclusions: Hemodynamic instability after PEA has been associated with higher postoperative plasma concentrations of IL-6 and IL-8. The positive relation between inflammatory cytokines and CI, or cytokines and vasopressor support, is in accordance with the hypothesis that cytokine activation may be among the neurohumoral factors responsible for cardiodepression and systemic vasoplegia in CTEPH patients undergoing PEA.