Level of systemic inflammation and endothelial injury is associated with cardiovascular dysfunction and vasopressor support in post-cardiac arrest patients.

AIM: Post-cardiac arrest syndrome (PCAS) is characterized by a sepsis-like inflammatory response and hemodynamic instability. We investigated the associations between systemic inflammation, endothelial damage and hemodynamic parameters including vasopressor support in patients with out-of-hospital cardiac arrest (OHCA).

METHODS

In this post-hoc study, we analysed data from 163 comatose patients included at a single center in the Target Temperature Management (TTM) trial, randomly assigned to TTM at 33°C or 36°C for 24h. Inflammatory biomarkers (interleukin (IL)-6, IL-10, procalcitonin and Tumor Necrosis Factor-α (TNF-α)) and endothelial biomarkers (thrombomodulin, sE-selectin, syndecan-1 and VE-cadherin) were measured at randomization and 24, 48 and 72h after OHCA. Corresponding hemodynamic status, heart rate (HR), mean arterial pressure (MAP) and Cumulative Vasopressor Index (CVI) was reported.

RESULTS

At randomization, level of IL-6 correlated negatively with MAP (r=-0.19, p=0.03) and positively with HR (r=0.29, p=0.0002). Serial IL-6 levels correlated consistently with CVI at 24h: (r=0.19, p=0.02) 48h: (r=0.31, p=0.0001) and 72h: (r=0.39, p<0.0001). Thrombomodulin (r=0.23, p=0.004) and syndecan-1 (r=0.27, p=0.001) correlated with CVI at 48h. All inflammatory markers excerpt IL-10 and all endothelial markers correlated with CVI at 72h. Multivariable regression models adjusting for potential confounders confirmed that IL-6 (β=0.2 (95% CI: 0.06-0.3), p=0.004) and TTM-group (TTM36: β=-0.5 (95% CI: -0.9 to 0.1), p=0.01) were associated with CVI at 48h. At 72h after OHCA, IL-6 (β=0.3 (95% CI: 0.03-0.6), p<0.0001), TNF-α (β=-0.4 (95% CI:- 0.5 to 0.2), p<0.0001) and TTM-group (TTM36: β=-0.4 (95% CI: -0.8 to 0.1), p=0.008) were associated with CVI. An overall two-fold increase in levels of IL-6 (β=0.2 (95% CI: 0.1-0.3), p<0.0001) and IL-10 (β=-0.2 (95% CI: -0.3 to 0.06), p=0.005) within 72h after OHCA were significantly associated with CVI. TTM-group modified the interaction between CVI and IL-6 (pinteraction=0.008), but not with IL-10 (pinteraction=0.23).

CONCLUSIONS

In comatose survivors after OHCA, increasing systemic inflammation and endothelial injury was associated with increased need of vasopressor support. Systemic inflammation, in particular IL-6, was consistently associated with vasopressor support, however endothelial injury may also play a role in PCAS associated cardiovascular dysfunction after OHCA.