Perioperative cardiovascular system failure in South Asians undergoing cardiopulmonary bypass is associated with prolonged inflammation and increased Toll-like receptor signaling in inflammatory monocytes

Dexamethasone for Cardiac Surgery: A Practice Preference-Randomized Consent Comparative Effectiveness Trial

BACKGROUND

High-dose corticosteroids have been used to attenuate the inflammatory response to cardiac surgery and cardiopulmonary bypass, but patient outcome benefits remain unclear. The primary aim was to determine whether using dexamethasone was superior to not using dexamethasone to increase the number of home days in the first 30 days after cardiac surgery. The secondary aim was to evaluate efficiency, value, and impact of the novel trial design.

METHODS

This pragmatic, international trial incorporating a prerandomized consent design favoring local practice enrolled patients undergoing cardiac surgery across seven hospitals in Australia and The Netherlands. Patients were randomly assigned to dexamethasone 1 mg/kg or not (control). The primary outcome was the number of days alive and at home up to 30 days after surgery ("home days"). Secondary outcomes included prolonged mechanical ventilation (more than 48 h), sepsis, renal failure, myocardial infarction, stroke, and death.

RESULTS

Of 2,562 patients assessed for eligibility, 1,951 were randomized (median age, 63 yr; 80% male). The median number of home days was 23.0 (interquartile range, 20.1 to 24.1) in the no dexamethasone group and 23.1 (interquartile range, 20.1 to 24.6) in the dexamethasone group (median difference, 0.1; 95% CI, -0.3 to 0.5; P = 0.66). The rates of prolonged mechanical ventilation (risk ratio, 0.72; 95% CI, 0.48 to 1.08), sepsis (risk ratio, 1.02; 95% CI, 0.57 to 1.82), renal failure (risk ratio, 0.94; 95% CI, 0.80 to 1.12), myocardial infarction (risk ratio, 1.20; 95% CI, 0.30 to 4.82), stroke (risk ratio, 1.06; 95% CI, 0.54 to 2.08), and death (risk ratio, 0.72; 95% CI, 0.22 to 2.35) were comparable between groups (all P > 0.10). Dexamethasone reduced intensive care unit stay (median, 29 h; interquartile range, 22 to 50 h vs. median, 43 h; interquartile range, 24 to 72 h; P = 0.004). The authors' novel trial design was highly efficient (89.3% enrollment).

CONCLUSIONS

Among patients undergoing cardiac surgery, high-dose dexamethasone decreased intensive care unit stay but did not increase the number of home days after surgery.

EDITOR’S PERSPECTIVE

Prospective Reassessment of the Association Between Pro-Inflammatory Factors and Prognosis After on-Pump Cardiac Surgery

AIM

Elevated levels of pro-inflammatory factors in plasma have been linked to worse prognosis after on-pump cardiac surgery, yet interventions that reduce the levels in patients have failed to improve prognosis. Therefore, we explored whether levels of pro-inflammatory factors are associated with prognosis of patients after valve surgery with cardiopulmonary bypass.

MATERIAL AND METHODS

244 patients were prospectively enrolled into observational study. Levels of tumor necrosis factor (TNF) - α, interleukin-8 and neutrophil elastase were measured once before and several times after cardiopulmonary bypass. The levels were compared between patients who experienced in-hospital adverse events or not, and between patients who experienced major adverse cardiac or cerebrovascular events (MACCEs) during three-year follow-up or not.

RESULTS

Of the 244 patients enrolled, in-hospital adverse events occurred in 38 (15.6 %); of the 237 patients who completed follow-up, MACCEs occurred in 30 (12.7 %). Surgery led to significant increases in levels of all three pro-inflammatory factors, with levels returning to pre-bypass baseline on arrival in the intensive care unit (TNF-α), 4 h after arrival (interleukin-8) or 20 h after arrival (neutrophil elastase). However, pre- and post-bypass levels of all three factors did not differ significantly between patients who experienced adverse events in-hospital or not, or between patients who experienced MACCEs during follow-up or not.

CONCLUSIONS

Levels of TNF-α, interleukin-8 and neutrophil elastase may not be associated with poor prognosis after cardiopulmonary bypass. This may help explain why "cytokine clearance" strategies fail to improve clinical outcomes after on-pump cardiac surgery.

Vascular Regenerative Cell Deficiencies in South Asian Adults

BACKGROUND

South Asian individuals shoulder a disproportionate burden of cardiometabolic diseases.

OBJECTIVES

The purpose of this study was to determine if vascular regenerative cell content varies significantly between South Asian and White European people.

METHODS

Between January 2022 and January 2023, 60 South Asian and 60 White European adults with either documented cardiovascular disease or established diabetes with ≥1 other cardiovascular risk factor were prospectively enrolled. Vascular regenerative cell content in venous blood was enumerated using a flow cytometry assay that is based on high aldehyde dehydrogenase (ALDHhi) activity and cell surface marker phenotyping. The primary outcome was the difference in frequency of circulating ALDHhi progenitor cells, monocytes, and granulocytes between the 2 groups.

RESULTS

Compared with White European participants, those of South Asian ethnicity were younger (69 ± 10 years vs 66 ± 9 years; P < 0.05), had lower weight (88 ± 19 kg vs 75 ± 13 kg; P < 0.001), and exhibited a greater prevalence of type 2 diabetes (62% vs 92%). South Asian individuals had markedly lower circulating frequencies of pro-angiogenic ALDHhiSSClowCD133+ progenitor cells (P < 0.001) and ALDHhiSSCmidCD14+CD163+ monocytes with vessel-reparative capacity (P < 0.001), as well as proportionally more ALDHhi progenitor cells with high reactive oxygen species content (P < 0.05). After correction for sex, age, body mass index, and glycated hemoglobin, South Asian ethnicity was independently associated with lower ALDHhiSSClowCD133+ cell count.

CONCLUSIONS

South Asian people with cardiometabolic disease had less vascular regenerative and reparative cells suggesting compromised vessel repair capabilities that may contribute to the excess vascular risk in this population. (The Role of South Asian vs European Origins on Circulating Regenerative Cell Exhaustion [ORIGINS-RCE]; NCT05253521).

Dexamethasone for Cardiac Surgery trial (DECS-II): Rationale and a novel, practice preference-randomized consent design

BACKGROUND

Numerous studies have investigated high-dose corticosteroids in cardiac surgery, but with mixed results leading to ongoing variations in practice around the world. DECS-II is a study comparing high-dose dexamethasone with placebo in patients undergoing cardiac surgery.

METHODS

We discuss the rationale for conducting DECS-II, a 2800-patient, pragmatic, multicenter, assessor-blinded, randomized trial in cardiac surgery, and the features of the DECS-II study design (objectives, end points, target population, based on practice preference with post-randomization consent, treatments, patient follow-up and analysis).

CONCLUSIONS

The DECS-II trial will use a novel, efficient trial design to evaluate whether high-dose dexamethasone has a patient-centered benefit of enhancing recovery and increasing the number of days at home after cardiac surgery.

Effects of TLR3 and TLR9 Signaling Pathway on Brain Protection in Rats Undergoing Sevoflurane Pretreatment during Cardiopulmonary Bypass

OBJECTIVE

To investigate the effects of TLR3 and TLR9 signaling pathway on brain injury during CPB in rats pretreated with sevoflurane and its possible molecular mechanism.

METHODS

SD rats were randomly assigned to sham group, CPB group, and Sev group. Brain tissue was obtained at before CPB (T0), at CPB for 30 minutes (T1), 1 hour after CPB (T3), and 3 hours after CPB (T5). ELISA was used to measure S100-β and IL-6. Western blot was utilized to determine TLR3 and TLR9 expression. TUNEL was applied to detect neuronal apoptosis.

RESULTS

Compared with CPB group, at T1, at termination after 1 hour of CPB (T2), T3, 2 hours after CPB (T4) and T5, S100-β and IL-6 decreased in Sev group. Compared with CPB group, IFN-β were increased in Sev group, except T0. Compared with CPB group, TLR3 expression increased, and TLR9 and NF-κB decreased in Sev group. The apoptotic neurons were less in Sev group than in CPB group (P < 0.05).

CONCLUSION

Sevoflurane intervention can activate TLR3 and TLR9 signaling pathway, upregulate TLR3 expression and downstream TRIF expression, decrease TLR9 expression, and downregulate downstream NF-κB expression in CPB rat models, thereby mitigating brain injury induced by inflammatory response during CPB.

Effect of cardiopulmonary bypass on cytochrome P450 enzyme activity: implications for pharmacotherapy

For patients undergoing cardiopulmonary bypass (CPB) during cardiac surgery, there are well-documented changes in the pharmacokinetics (PK) of commonly administered drugs. Although multiple factors potentially underpin these changes, there has been scant research attention on the impact of CPB to alter the activities of cytochrome P450 (CYP) isoenzymes. PK changes during cardiac surgery with CPB have the potential to adversely affect the safety and efficacy of pharmacotherapy and increase the risk of drug-drug interactions. Clinically significant changes in drug PK during CPB are likely to be prominent for drugs where CYP metabolism is a major clearance (CL) mechanism. However, clinical data from patients undergoing CPB surgery in support of this hypothesis are lacking, leaving a significant knowledge gap. In this review, we address the effects of CPB on the release of pro-inflammatory cytokines, in surgeries with and without CPB, both pre and post initiation of surgery. We reviewed literature to explore the relationship between the release of pro-inflammatory cytokines, and the expression and activities of CYP enzymes. Through this approach, we provide new insight on the effects of CPB on the PK of drugs administered to patients in the clinical setting. Future research to address this knowledge gap will have considerable impact to assist clinicians with optimizing pharmacotherapy in this patient population.

Dexmedetomidine reduces the neuronal apoptosis related to cardiopulmonary bypass by inhibiting activation of the JAK2-STAT3 pathway

Cardiopulmonary bypass (CPB) constitutes one of the primary methodologies pertaining to cardiac surgery. However, this form of surgery can cause damage to the body. Many studies have reported that dexmedetomidine confers cerebral protection. In this study, we aimed to investigate the effect and mechanism of dexmedetomidine on neuronal apoptosis caused by CPB. Here, rats were treated with different doses of dexmedetomidine by intravenous infusion 2 hours after CPB. We observed that dexmedetomidine treatment to rats reduces the S100β, NSE levels in plasma, and neuronal apoptosis following CPB in a dose-dependent manner. Furthermore, we observed that the beneficial effect of dexmedetomidine treatment following CPB was associated with a reduction in IL6, an inflammatory cytokine in plasma and cortex. Our results suggest that dexmedetomidine provides neuroprotective effects by inhibiting inflammation and reducing neuronal apoptosis. There was a correlation between the protective effect on the brain and the dose of dexmedetomidine. In addition, dexmedetomidine administration inhibits phosphorylation of JAK2 and STAT3 proteins in the hippocampus of rats 2 hours after CPB. Therefore, we speculate that the JAK2–STAT3 pathway plays an important role in the neuroprotective effects of dexmedetomidine following brain injury induced by CPB.

Cardiovascular risk among South Asians living in Canada: a systematic review and meta-analysis

BACKGROUND

South Asians represent about 3% of the Canadian population and have a higher burden of certain cardiovascular risk factors and cardiovascular disease (CVD) compared with white people. The objective of this study was to review the literature to compare cardiovascular risk factors and disease management practices among adult South Asian and white Canadians.

METHODS

We searched MEDLINE, Embase, Cochrane and Cumulative Index to Nursing and Allied Health Literature databases from their inception through Feb. 17, 2014 and the reference lists of the selected articles. English-language studies of interventions and observational studies of biological mechanisms underlying CVD risk in South Asians conducted in Canada were eligible for inclusion. Where appropriate, we used random-effects meta-analyses to integrate results comparing the CVD risk profiles of South Asian and white Canadians.

RESULTS

We included 50 articles (n = 5 805 313 individuals) in this review. Compared with white Canadians, South Asian Canadians had a higher prevalence and incidence of CVD, an increased prevalence of diabetes (odds ratio [OR] 2.25, 95% confidence interval [CI] 1.81 to 2.80, p < 0.001) and hypertension (OR 1.11, 95% CI 1.02 to 1.22, p = 0.02), lower high-density lipoprotein cholesterol levels (mean difference -0.19 mmol/L, 95% CI -0.25 to -0.13 mmol/L, p < 0.001) and a higher percentage of body fat (men: absolute mean difference 3.23%, 95% CI 0.83% to 5.62%, p = 0.008; women: absolute mean difference 4.09%, 95% CI 3.46% to 4.72%, p < 0.001). South Asian people are also more sedentary, consume higher levels of carbohydrates and are less likely to smoke tobacco (OR 0.38, 95% CI 0.24 to 0.60, p < 0.001]) than white Canadians. No differences in access to diagnostic tests, outcomes following cardiovascular surgery or use of cardiac rehabilitation programs were apparent.

INTERPRETATION

Compared with white people, South Asian people living in Canada have a higher prevalence and incidence of CVD and possess a unique cardiovascular risk profile.