Anti-inflammatory effect of tranexamic acid on adult cardiac surgical patients: A PRISMA-compliant systematic review and meta-analysis

Objective

This study aims to evaluate the anti-inflammatory effect of tranexamic acid (TXA) on adult cardiac surgical patients.

Methods

PubMed, Embase, Ovid, Web of Science, CNKI, VIP, and WANFANG databases were systematically searched using the related keywords for cardiac surgical randomized controlled trials (RCTs) published from their inception to February 1, 2022. The primary outcomes were postoperative inflammatory biomarkers levels. The secondary outcomes were postoperative systemic inflammatory response syndrome and other major postoperative outcomes. The odds ratios and/or the weighted mean difference (WMD) with a 95% confidence interval (CI) were used to pool the data.

Results

Ten RCTs with 770 adult cardiac surgical patients were included. Compared with placebo, TXA achieved statistically significant inhibition of the postoperative interleukin (IL)-6 level (postoperative 6 h: n = 6 trials; WMD -31.66; 95% CI: -45.90, -17.42; p < 0.0001; I ²= 93%; postoperative 24 h: n =  8 trials; WMD, -44.06; 95% CI: -69.21, -18.91; p = 0.006; I ²= 100%); IL-8 level postoperative 24 h, TNF-α level postoperative 24 h, NE level postoperative 6 h: n = 3 trials; WMD, -36.83; 95% CI: -68.84, -4.83; p = 0.02; I ²= 95%); tissue necrosis factor alpha (TNF-α) level (postoperative 6 h: n = 3 trials; WMD, -7.21; 95% CI: -12.41, -2.01; p = 0.007; I ²= 47%; postoperative 24 h: n = 5 trials; WMD, -10.02; 95% CI: -14.93, -5.12; p < 0.0001; I ²= 94%); and neutrophil elastase (NE) level (postoperative 6 h: n = 3 trials; WMD, -66.93; 95% CI: -111.94, -21.92; p = 0.004; I ²= 86%). However, TXA achieved no statistically significant influence on the postoperative 24 h NE level.

Conclusions

TXA had a significant anti-inflammatory effect in adult cardiac surgical patients, as evidenced by the reduction of multiple postoperative proinflammatory biomarkers levels, but these results should be interpreted carefully and cautiously, as only a limited number of studies were included and there was high heterogeneity between them.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022312919.

A Weak Response to Endoplasmic Reticulum Stress Is Associated With Postoperative Organ Failure in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass

Introduction: Endoplasmic reticulum stress (ERS) is involved in inflammatory organ failure. Our objective was to describe ERS, its unfolded protein response (UPR) expression/kinetics during cardiac surgery with cardiopulmonary bypass (CPB) and its association with postoperative organ failure (OF). Methods: Prospective study conducted on patients undergoing cardiac surgery with CPB. Blood samples were taken before (Pre-CPB), 2 h (H2-CPB) and 24 h (H24-CPB) after CPB. Plasma levels of 78 kDa Glucose- Regulated Protein (GRP78, final effector of UPR) were evaluated by ELISA. The expression of genes coding for key elements of UPR (ATF6, ATF4, sXBP1, CHOP) was evaluated by quantitative PCR performed on total blood. OF was defined as invasive mechanical ventilation and/or acute kidney injury and/or hemodynamic failure requiring catecholamines. Results: We included 46 patients, GRP78 was decreased at H2-CPB [1,328 (878-1,730) ng/ml vs. 2,348 (1,655-3,730) ng/ml Pre-CPB; p < 0.001] but returned to basal levels at H24-CPB [2,068 (1,436-3,005) ng/ml]. The genes involved in UPR had increased expression at H2 and H24. GRP78 plasma levels in patients with OF at H24-CPB (n = 10) remained below Pre-CPB levels [-27.6 (-51.5; -24.2)%] compared to patients without OF (n = 36) in whom GRP78 levels returned to basal levels [0.6 (-28.1; 26.6)%; p < 0.01]. H24-CPB ATF6 and CHOP expressions were lower in patients with OF than in patients without OF [2.3 (1.3-3.1) vs. 3.0 (2.7-3.7), p < 0.05 and 1.3 (0.9-2.0) vs. 2.2 (1.7-2.9), p < 0.05, respectively]. Conclusions: Low relative levels of GRP78 and weak UPR gene expression appeared associated with postoperative OF. Further studies are needed to understand ERS implication during acute organ failure in humans.

Consensus statement: minimal criteria for reporting the systemic inflammatory response to cardiopulmonary bypass

The lack of established cause and effect between putative mediators of inflammation and adverse clinical outcomes has been responsible for many failed anti-inflammatory interventions in cardiopulmonary bypass (CPB). Candidate interventions that impress in preclinical trials by suppressing a given inflammation marker might fail at the clinical trial stage because the marker of interest is not linked causally to an adverse outcome. Alternatively, there exist examples in which pharmaceutical agents or other interventions improve clinical outcomes but for which we are uncertain of any antiinflammatory mechanism. The Outcomes consensus panel made 3 recommendations in 2009 for the conduct of clinical trials focused on the systemic inflammatory response. This panel was tasked with updating, as well as simplifying, a previous consensus statement. The present recommendations for investigators are the following: (1) Measure at least 1 inflammation marker, defined in broad terms; (2) measure at least 1clinical end point, drawn from a list of practical yet clinically meaningful end points suggested by the consensus panel; and(3) report a core set of CPB and perfusion criteria that maybe linked to outcomes. Our collective belief is that adhering to these simple consensus recommendations will help define the influence of CPB practice on the systemic inflammatory response, advance our understanding of causal inflammatory mechanisms, and standardize the reporting of research findings in the peer-reviewed literature.