Cardiopulmonary Bypass-Induced Inflammation and Myocardial Ischemia and Reperfusion Injury Stimulates Accumulation of Soluble MER

Analysis of influencing factors for postoperative brain injury in patients with cardiac surgery

OBJECTIVE

To identify risk factors in people with heart disease prior to undergoing cardiac surgery and to provide a prediction model.

METHODS

106 patients who underwent cardiac surgery were selected by convenience sampling method. Case-control study design was used to divide them into control and observation groups according to whether there was postoperative brain injury. General demographic data, perioperative surgery, postoperative recovery, past medical history and preoperative conditions, laboratory test indicators were collected. Univariate and multivariate Logistic regression analyses were performed to select influencing factors. A nomogram model for predicting postoperative brain injury was established.

RESULTS

Univariate Logistic regression analysis showed that age, female, stroke, diabetes mellitus, perioperative administration of dexmedetomidine, intraoperative use of cardiopulmonary bypass were related factors for postoperative brain injury(p < 0.05). Multivariate Logistic regression analysis showed that females, history of stroke, and intraoperative use of cardiopulmonary bypass were risk factors, and perioperative administration of dexmedetomidine was protective factor(p < 0.05). Nomogram model was established with an AUC of 0.847 and accuracy of 84.7%.

CONCLUSION

Preoperative stroke history and females are risk factors for brain injury after coronary artery bypass grafting under cardiopulmonary bypass, and perioperative use of dexmedetomidine is protective factor.

Biochemical Changes in Cardiopulmonary Bypass in Cardiac Surgery: New Insights

Patients undergoing coronary revascularization with extracorporeal circulation or cardiopulmonary bypass (CPB) may develop several biochemical changes in the microcirculation that lead to a systemic inflammatory response. Surgical incision, post-CPB reperfusion injury and blood contact with non-endothelial membranes can activate inflammatory signaling pathways that lead to the production and activation of inflammatory cells, with cytokine production and oxidative stress. This inflammatory storm can cause damage to vital organs, especially the heart, and thus lead to complications in the postoperative period. In addition to the organic pathophysiology during and after the period of exposure to extracorporeal circulation, this review addresses new perspectives for intraoperative treatment and management that may lead to a reduction in this inflammatory storm and thereby improve the prognosis and possibly reduce the mortality of these patients.

Risk factors for venoarterial-extracorporeal membrane oxygenation related nosocomial infection in children after cardiac surgery

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) is an extracorporeal life support strategy for the treatment of critically ill children with reversible heart and lung failure, increasingly being used in patients with low cardiac output after cardiac surgery. However, the mortality of patients is closely related to the complications of ECMO, especially bleeding, thrombosis, and infection, ECMO-related nosocomial infection has become a challenge to the success of ECMO. This study aims to analyze the incidence and risk factors for venoarterial-ECMO (VA-ECMO)-related nosocomial infections in children after cardiac surgery.

METHODS

We retrospectively collected the data of patients who underwent VA-ECMO treatment after pediatric cardiac surgery in the Second Xiangya Hospital of Central South University from July 2015 to March 2021, and divided them into an infected group and a non-infected group. The clinical characteristics of the 2 groups of patients, VA-ECMO-related nosocomial infection factors, pathogenic microorganisms, and patient mortality were compared. Logistic regression was used to analyze the risk factors for nosocomial infection related to VA-ECMO after cardiac surgery.

RESULTS

Of the 38 pediatric patients, 18 patients (47.37%) had VA-ECMO related nosocomial infection, served as the infected group, including 7 patients with blood infections and 11 respiratory tract infections. Gram-negative pathogens (16 strains, 88.9%) were the main bacteria, such as Acinetobacter baumannii (6 strains), Klebsiella pneumoniae (3 strains), and Stenotrophomonas maltophilia (3 strains). Compared with the non-infected group (n=20), the infection group had longer time of cardiopulmonary bypass, time of myocardial block, and time of VA-ECMO assistance (All P<0.05). Multivariate logistic regression analysis showed that time of cardiopulmonary bypass (OR=1.012, 95% CI 1.002 to 1.022; P=0.021) was an independent risk factor for ECMO-related nosocomial infection. The number of surviving discharges in the infected group was less than that in the non-infected group (1 vs 11, P<0.05).

CONCLUSIONS

Cardiopulmonary bypass time is an independent risk factor for VA-ECMO-related nosocomial infection in children after cardiac surgery. Shortening the duration of extracorporeal circulation may reduce the incidence of VA-EMCO-related nosocomial infections in children after cardic surgery. The occurrence of VA-ECMO-related nosocomial infections affects the number of patient's discharge alive.

Hypoxia-inducible factors individually facilitate inflammatory myeloid metabolism and inefficient cardiac repair

Hypoxia-inducible factors (HIFs) are activated in parenchymal cells in response to low oxygen and as such have been proposed as therapeutic targets during hypoxic insult, including myocardial infarction (MI). HIFs are also activated within macrophages, which orchestrate the tissue repair response. Although isoform-specific therapeutics are in development for cardiac ischemic injury, surprisingly, the unique role of myeloid HIFs, and particularly HIF-2α, is unknown. Using a murine model of myocardial infarction and mice with conditional genetic loss and gain of function, we uncovered unique proinflammatory roles for myeloid cell expression of HIF-1α and HIF-2α during MI. We found that HIF-2α suppressed anti-inflammatory macrophage mitochondrial metabolism, while HIF-1α promoted cleavage of cardioprotective MerTK through glycolytic reprogramming of macrophages. Unexpectedly, combinatorial loss of both myeloid HIF-1α and HIF-2α was catastrophic and led to macrophage necroptosis, impaired fibrogenesis, and cardiac rupture. These findings support a strategy for selective inhibition of macrophage HIF isoforms and promotion of anti-inflammatory mitochondrial metabolism during ischemic tissue repair.