Intraoperative transfusion and an increased preoperative C-reactive protein level are associated with higher mortality after off-pump coronary artery bypass grafting

Associations of Inflammatory Biomarkers With the Risk of Morbidity and Mortality After Cardiac Surgery: A Systematic Review and Meta-analysis

BACKGROUND

Although inflammatory biomarkers have been associated with cardiovascular events in nonsurgical settings, these associations have not been systematically addressed in patients undergoing cardiac surgery. This review aimed to evaluate the relationships of inflammatory markers with mortality and adverse cardiovascular events in patients undergoing cardiac surgery.

METHODS

Medline, Embase, and Central databases were systematically searched for studies reporting pre- or postoperative levels of inflammatory biomarkers in patients undergoing cardiac surgery. Outcomes of interest were postoperative mortality, nonfatal myocardial infarction, stroke, congestive heart failure, and major adverse cardiovascular events (MACE). Studies reporting multivariable adjusted risk estimates were included. Risk estimates were pooled with the use of random-effects models and reported as summary odds ratios (ORs).

RESULTS

Among 14,465 citations identified, 29 studies including 29,401 participants met the eligibility criteria. The average follow-up time after surgery was 31 months. Preoperative C-reactive protein (CRP) levels were associated with an increased risk of all-cause mortality (OR 1.88, 95% CI 1.60-2.20; I2 = 19%; 11 studies) and MACE (OR 1.73, 95% CI 1.34-2.24; I2 = 0%; 3 studies). CRP levels measured on postoperative day 6 (OR 7.4, 95% CI 2.90-18.88, 1 study) and day 10 (OR 11.8, 95% CI 3.50-39.78, 1 study) were associated with a higher risk of all-cause mortality. Less, but overall similar, information was available for other inflammatory biomarkers.

CONCLUSIONS

In this large meta-analysis, inflammatory biomarkers measured before or after cardiac surgery were associated with mortality and adverse cardiovascular outcomes in patients undergoing cardiac surgery.

Preoperative inflammatory markers predict postoperative clinical outcomes in patients undergoing heart valve surgery: A large-sample retrospective study

Introduction

Preoperative inflammation affects the postoperative outcomes of patients undergoing heart valve surgery. This study aimed to explore the role and predictive effects of preoperative inflammation on the primary outcomes after valvular cardiac surgery.

Methods

This retrospective study utilized a medical recording system to screen 5075 patients who underwent heart valve surgery. Data on the C-reactive protein (CRP) levels, erythrocyte sedimentation rate (ESR), and neutrophil-to-lymphocyte ratio (NLR) before heart valve surgery were collected from the hospital’s medical system. Postoperative hepatic insufficiency, acute kidney injury, heart failure, and myocardial damage were assessed using blood indicators. Patients with and without prolonged mechanical ventilation, extended intensive care unit stays, prolonged hospital stays, and death within 30 days after surgery (considered the primary outcome in this study) were compared. Group comparisons, receiver operating characteristic (ROC) curve analyses, and logistic analyses were performed to determine the associations between preoperative inflammation and outcomes after heart valve surgery.

Results

A total of 3249 patients were included in the analysis. Significant differences in CRP level, ESR, and NLR were found between patients with and without postoperative adverse outcomes. ROC analysis showed that CRP levels >5 mg/L effectively predicted postoperative heart failure, and NLR >3.5 had a good predictive effect on all-cause mortality within 30 days after surgery. Patients with CRP levels >5 mg/L had a higher incidence of postoperative heart failure than other patients (20.7% vs. 12.6%, P<0.001), with a relative risk of 1.447 (95% confidence interval: 1.155–1.814). Patients with NLR >3.5 had a higher incidence of death within 30 days after surgery (5.3% vs. 1.2%, P<0.001), with a relative risk of 3.236 (95% confidence interval: 1.773–5.906).

Conclusion

Preoperative inflammation can affect postoperative outcomes in patients undergoing heart valve surgery. CRP level >5 mg/L and NLR >3.5 can effectively predict postoperative heart failure and death within 30 days after surgery, respectively.

Can C-reactive protein predict coagulation in off pump coronary artery bypass grafting? A cohort study

Background

Previous study found that C-reactive protein (CRP) can predict bleeding after on-pump CABG. To evaluate whether preoperative C-reactive protein (CRP) can be a novel marker of postoperative bleeding in patients having off-pump coronary artery bypass grafting (CABG).

Methods

This is a retrospective cohort study. Multiple variable regression analyses were performed. 537 patients undergoing off-pump isolated primary CABG at Fuwai Hospital from September 2017 to July 2018 were recorded. The primary endpoint was bleeding volume within 24 h after surgery.

Results

Data of 537 patients undergoing off-pump isolated primary CABG at Fuwai Hospital were recorded. The correlations between bleeding volume within 24 h after surgery and preoperative data were analyzed with univariate and multivariate linear regression. Much more preoperative CRP concentration (B = −0.089, P < 0.05) was associated with less postoperative bleeding volume and fibrinogen (B = 0.594, p < 0.001).

Conclusions

Preoperative CRP concentration is independently correlated with the postoperative volume of bleeding within 24 h. CRP may become a novel coagulation index in coronary artery atherosclerotic disease.

Intraoperative mild hyperoxia may be associated with improved survival after off-pump coronary artery bypass grafting: a retrospective observational study

Background

The effect of hyperoxia due to supplemental oxygen administration on postoperative outcomes in patients undergoing cardiac surgery remains unclear. This retrospective study aimed to evaluate the relationship between intraoperative oxygen tension and mortality after off-pump coronary artery bypass grafting (OPCAB).

Methods

The study included adult patients who underwent isolated OPCAB between July 2010 and June 2020. Patients were categorised into three groups based on their intraoperative time-weighted average arterial oxygen partial pressure (PaO₂): normoxia/near-normoxia (< 150 mmHg), mild hyperoxia (150–250 mmHg), and severe hyperoxia (> 250 mmHg). The risk of in-hospital mortality was compared using weighted logistic regression analysis. Restricted cubic spline analysis was performed to analyse intraoperative PaO₂ as a continuous variable. The risk of cumulative all-cause mortality was compared using Cox regression analysis.

Results

The normoxia/near-normoxia, mild hyperoxia, and severe hyperoxia groups included 229, 991, and 173 patients (n = 1393), respectively. The mild hyperoxia group had a significantly lower risk of in-hospital mortality than the normoxia/near-normoxia (odds ratio [OR], 0.12; 95% confidence interval [CI], 0.06–0.22) and severe hyperoxia groups (OR, 0.06; 95% CI, 0.03–0.14). Intraoperative PaO₂ exhibited a U-shaped relationship with in-hospital mortality in the non-hypoxic range. The risk of cumulative all-cause mortality was significantly lower in the mild hyperoxia group (hazard ratio, 0.72; 95% CI, 0.52–0.99) than in the normoxia/near-normoxia group.

Conclusions

Maintaining intraoperative PaO₂ at 150–250 mmHg was associated with a lower risk of mortality after OPCAB than PaO₂ at < 150 mmHg and at > 250 mmHg. Future randomised trials are required to confirm if mildly increasing arterial oxygen tension during OPCAB to 150–250 mmHg improves postoperative outcomes.

Effect of changes in inspired oxygen fraction on oxygen delivery during cardiac surgery: a substudy of the CARROT trial

When hemoglobin (Hb) is fully saturated with oxygen, the additional gain in oxygen delivery (DO2) achieved by increasing the fraction of inspired oxygen (FiO2) is often considered clinically insignificant. In this study, we evaluated the change in DO2, interrogated by mixed venous oxygen saturation (SvO2), in response to a change in FiO2 of 0.5 during cardiac surgery. When patients were hemodynamically stable, FiO2 was alternated between 0.5 and 1.0 in on-pump cardiac surgery patients (pilot study), and between 0.3 and 0.8 in off-pump coronary artery bypass grafting patients (substudy of the CARROT trial). After the patient had stabilized, a blood gas analysis was performed to measure SvO2. The observed change in SvO2 (ΔSvO2) was compared to the expected ΔSvO2 calculated using Fick's equation. A total 106 changes in FiO2 (two changes per patient; total 53 patients; on-pump, n = 36; off-pump, n = 17) were finally analyzed. While Hb saturation remained near 100% (on-pump, 100%; off-pump, mean [SD] = 98.1% [1.5] when FiO2 was 0.3 and 99.9% [0.2] when FiO2 was 0.8), SvO2 changed significantly as FiO2 was changed (the first and second changes in on-pump, 7.7%p [3.8] and 7.6%p [3.5], respectively; off-pump, 7.9%p [4.9] and 6.2%p [3.9]; all P < 0.001). As a total, regardless of the surgery type, the observed ΔSvO2 after the FiO2 change of 0.5 was ≥ 5%p in 82 (77.4%) changes and ≥ 10%p in 31 (29.2%) changes (mean [SD], 7.5%p [3.9]). Hb concentration was not correlated with the observed ΔSvO2 (the first changes, r =  - 0.06, P = 0.677; the second changes, r =  - 0.21, P = 0.138). The mean (SD) residual ΔSvO2 (observed - expected ΔSvO2) was 0%p (4). Residual ΔSvO2 was more than 5%p in 14 (13.2%) changes and exceeded 10%p in 2 (1.9%) changes. Residual ΔSvO2 was greater in patients with chronic kidney disease than in those without (median [IQR], 5%p [0 to 7] vs. 0%p [- 3 to 2]; P = 0.049). DO2, interrogated by SvO2, may increase to a clinically significant degree as FiO2 is increased during cardiac surgery, and the increase of SvO2 is not related to Hb concentration. SvO2 increases more than expected in patients with chronic kidney disease. Increasing FiO2 can be used to increase DO2 during cardiac surgery.