Association of perioperative transfusion of fresh frozen plasma and outcomes after cardiac surgery.

BACKGROUND: Fresh frozen plasma (FFP) transfusion is used to manage coagulopathy and bleeding in cardiac surgery patients despite uncertainty about its safety and effectiveness. METHODS: We performed a propensity score matched analysis of the Australian and New Zealand Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database including patients from 39 centres from 2005 to 2018. We investigated the association of perioperative FFP transfusion with mortality and other clinical outcomes. RESULTS: Of 119,138 eligible patients, we successfully matched 13,131 FFP recipients with 13,131 controls. FFP transfusion was associated with 30-day mortality (odds ratio (OR), 1.41; 99% CI, 1.17-1.71; p < .0001), but not with long-term mortality (hazard ratio (HR), 0.92; 99% CI, 0.85-1.00; p = .007, Holm-Bonferroni α = 0.0004). FFP was also associated with return to theatre for bleeding (OR, 1.97; 99% CI, 1.66-2.34; p < .0001), prolonged intubation (OR, 1.15; 99% CI, 1.05-1.26; p < .0001) and increased chest tube drainage (Mean difference (MD) in mL, 131; 99% CI, 120-141; p < .0001). It was also associated with reduced postoperative creatinine levels (MD in g/L, -6.33; 99% CI, -10.28 to -2.38; p < .0001). CONCLUSION: In a multicentre, propensity score matched analysis, perioperative FFP transfusion was associated with increased 30-day mortality and had variable associations with secondary clinical outcomes.

Sex Differences in Opioid Administration After Cardiac Surgery.

OBJECTIVES: To assess whether there are sex-based differences in the administration of opioid analgesic drugs among inpatients after cardiac surgery. DESIGN: A retrospective cohort study. SETTING: At a tertiary academic referral center. PARTICIPANTS: Adult patients who underwent cardiac surgery from 2014 to 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the cumulative oral morphine equivalent dose (OMED) for the postoperative admission. Secondary outcomes were the daily difference in OMED and the administration of nonopioid analgesics. The authors developed multivariate regression models controlling for known confounders, including weight and length of stay. A total of 3,822 patients (1,032 women and 2,790 men) were included. The mean cumulative OMED was 139 mg for women and 180 mg for men, and this difference remained significant after adjustment for confounders (adjusted mean difference [aMD], -33.21 mg; 95% CI, -47.05 to -19.36 mg; p < 0.001). The cumulative OMED was significantly lower in female patients on postoperative days 1 to 5, with the greatest disparity observed on day 5 (aMD, -89.83 mg; 95% CI, -155.9 to -23.80 mg; p = 0.009). By contrast, women were more likely to receive a gabapentinoid (odds ratio, 1.91; 95% CI, 1.42-2.58; p < 0.001). The authors found no association between patient sex and the administration of other nonopioid analgesics or specific types of opioid analgesics. The authors found no association between patient sex and pain scores recorded within the first 48 hours after extubation, or the number of opioids administered in close proximity to pain assessments. CONCLUSIONS: Female sex was associated with significantly lower amounts of opioids administered after cardiac surgery.

Platelet Transfusion in Cardiac Surgery: An Entropy-Balanced, Weighted, Multicenter Analysis.

BACKGROUND: Platelet transfusion is common in cardiac surgery, but some studies have suggested an association with harm. Accordingly, we investigated the association of perioperative platelet transfusion with morbidity and mortality. METHODS: We conducted a retrospective analysis of prospectively collected data from the Australian Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database. We included consecutive adults from 2005 to 2018 across 40 centers. We used inverse probability of treatment weighting via entropy balancing to investigate the association of perioperative platelet transfusion with our 2 primary outcomes, operative mortality (composite of both 30-day and in-hospital mortality) and 90-day mortality, as well as multiple other clinically relevant secondary outcomes. RESULTS: Among 119,132 eligible patients, 25,373 received perioperative platelets and 93,759 were considered controls. After entropy balancing, platelet transfusion was associated with reduced operative mortality (odds ratio [OR], 0.63; 99% confidence interval [CI], 0.47-0.84; P < .0001) and 90-day mortality (OR, 0.66; 99% CI, 0.51-0.85; P < .0001). Moreover, it was associated with reduced odds of deep sternal wound infection (OR, 0.57; 99% CI, 0.36-0.89; P = .0012), acute kidney injury (OR, 0.84; 99% CI, 0.71-0.99; P = .0055), and postoperative renal replacement therapy (OR, 0.71; 99% CI, 0.54-0.93; P = .0013). These positive associations were observed despite an association with increased odds of return to theatre for bleeding (OR, 1.55; 99% CI, 1.16-2.09; P < .0001), pneumonia (OR, 1.26; 99% CI, 1.11-1.44; P < .0001), intubation for longer than 24 hours postoperatively (OR, 1.13; 99% CI, 1.03-1.24; P = .0012), inotrope use for >4 hours postoperatively (OR, 1.14; 99% CI, 1.11-1.17; P < .0001), readmission to hospital within 30 days of surgery (OR, 1.22; 99% CI, 1.11-1.34; P < .0001), as well as increased drain tube output (adjusted mean difference, 89.2 mL; 99% CI, 77.0 mL-101.4 mL; P < .0001). CONCLUSIONS: In cardiac surgery patients, perioperative platelet transfusion was associated with reduced operative and 90-day mortality. Until randomized controlled trials either confirm or refute these findings, platelet transfusion should not be deliberately avoided when considering odds of death.

Fresh frozen plasma transfusion after cardiac surgery.

INTRODUCTION: Fresh frozen plasma (FFP) transfusion in the intensive care unit (ICU) is commonly used to treat coagulopathy and bleeding in cardiac surgery, despite suggestion that it may increase the risk of morbidity and mortality through mechanisms such as fluid overload and infection. METHODS: We retrospectively studied consecutive adults undergoing cardiac surgery from the Medical Information Mart for Intensive Care III and IV databases. We applied propensity score matching to investigate the independent association of within-ICU FFP transfusion with mortality and other key clinical outcomes. RESULTS: Of our 12,043 adults who met inclusion criteria, 1585 (13.2%) received perioperative FFP with a median of 2.48 units per recipient (interquartile range [IQR]: 2.04, 4.33) at a median time of 1.83 h (IQR: 0.75, 3.75) after ICU admission. After propensity matching of 952 FFP recipients to 952 controls, we found no significant association between FFP use and hospital mortality (odds ratio (OR): 1.58; 99% confidence interval (CI): 0.57, 3.71), suspected infection (OR: 0.72; 99% CI: 0.49, 1.08), or acute kidney injury (OR: 1.23; 99% CI: 0.91, 1.67). However, FFP was associated with increased days in hospital (adjusted mean difference (AMD): 1.28; 99% CI: 0.27, 2.41; p = .0050), days in intensive care (AMD: 1.28; 99% CI: 0.27, 2.28; p = .0011), and chest tube output in millilitres up to 8 h after transfusion (AMD: 92.98; 99% CI: 52.22, 133.74; p < .0001). CONCLUSIONS: After propensity matching, FFP transfusion was not associated with increased hospital mortality, but was associated with increased length of stay and no decrease in bleeding in the early post-transfusion period.

Weekend effect in emergency laparotomy: a propensity score-matched analysis.

BACKGROUND: The 'weekend effect' is the term given to the observed discrepancy regarding patient care and outcomes on weekends compared to weekdays. This study aimed to determine whether the weekend effect exists within Aotearoa New Zealand (AoNZ) for patients undergoing emergency laparotomy (EL), given recent advances in management of EL patients. METHODS: A cohort study was conducted across five hospitals, comparing the outcomes of weekend and weekday acute EL. A propensity-score matched analysis was used to remove potential confounding patient characteristics. RESULTS: Of the 487 patients included, 132 received EL over the weekend. There was no statistically significant difference between patients undergoing EL over the weekend compared to weekdays. Mortality rates were comparable between the weekday and weekend cohorts (P = 0.464). CONCLUSIONS: These results suggest that modern perioperative care practice in New Zealand obviates the 'weekend' effect.

Association of Perioperative Cryoprecipitate Transfusion and Mortality After Cardiac Surgery.

BACKGROUND: Cryoprecipitate is often transfused in patients undergoing cardiac surgery. However, its safety and effectiveness remain uncertain. METHODS: This study was a propensity score-matched analysis of data from the Australian and New Zealand Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database. The study included adults undergoing cardiac surgery between 2005 and 2018 across 38 sites. The association between perioperative cryoprecipitate transfusion and clinical outcomes was estimated, with a primary outcome of operative mortality. RESULTS: Of 119,132 eligible patients, 11,239 (9.43%) patients received cryoprecipitate. The median cumulative dose was 8 U (interquartile range, 5-10 U). After propensity score matching, we matched 9055 cryoprecipitate recipients to 9055 control subjects. Postoperative cryoprecipitate transfusion was associated with reduced operative mortality (odds ratio [OR], 0.82; 99% CI, 0.69-0.97; P = .002) and long-term mortality (hazard ratio, 0.92; 99% CI, 0.87-0.97; P = .0042). It was also associated with a reduction in acute kidney injury (OR, 0.85; 99% CI, 0.73-0.98; P = .0037) and all-cause infection (OR, 0.77; 99% CI, 0.67-0.88; P < .0001). These findings were observed despite increased rates of return to the operating room (OR, 1.36; 99% CI, 1.22-1.51; P < .0001) and cumulative 4-hour postoperative chest tube output (adjusted mean difference in mL, 97.69; 99% CI, 81.65;113.74; P < .0001). CONCLUSIONS: In a large, multicenter cohort study and after propensity score matching, perioperative transfusion of cryoprecipitate was associated with reduced operative and long-term mortality.

The Prognostic Significance of Red Cell Distribution Width in Cardiac Surgery: A Systematic Review and Meta-Analysis.

RED CELL DISTRIBUTION WIDTH (RDW) is a routinely available biomarker of likely erythropoietic dysfunction, which may be associated with adverse outcomes after cardiac surgery. This systematic review and meta-analysis aimed to clarify the prognostic value of RDW in patients undergoing cardiac surgery. The authors searched MEDLINE, Embase, and the Cochrane Library from inception to May 10, 2022 for studies investigating the association between elevated RDW (as defined by the authors of included studies) and adverse outcomes after cardiac surgery. Herein, the authors extracted maximally adjusted hazard ratios (HRs) and odds ratios (ORs) with associated CIs, and pooled them using random-effects inverse- variance modeling. The authors explored interstudy heterogeneity using metaregression. The authors included 26 studies involving 48,092 patients who had undergone cardiac surgery. Elevated preoperative RDW was associated with long-term mortality (pooled HR 1.63, 95% CI 1.05-2.52), short-term mortality (pooled OR 2.16, 95% CI 1.21-3.87), acute kidney injury (AKI; pooled OR 1.30, 95% CI 1.19-1.41) and postoperative atrial fibrillation (POAF; pooled OR 1.44, 95% CI 1.05-1.96). Some studies suggested a significant association between preoperative RDW elevation and neurologic complications; however, their number was insufficient for meta-analysis. The postoperative RDW levels were less consistently reported and could not be meta-analyzed. In conclusion, the authors found that elevated preoperative RDW was associated with increased short- and long-term mortality, POAF, and AKI after cardiac surgery. Further research is needed to investigate its role in the risk stratification of patients undergoing cardiac surgery.

Platelet Transfusion After Cardiac Surgery.

OBJECTIVES: To investigate the independent association of platelet transfusion with hospital mortality and key relevant clinical outcomes in cardiac surgery. DESIGN: A single-center, propensity score-matched, retrospective, cohort study. SETTING: At an American tertiary teaching hospital data from the Medical Information Mart for Intensive Care III and IV databases from 2001 to 2019. PARTICIPANTS: Consecutive adults undergoing coronary artery bypass graft and/or cardiac valvular surgery. INTERVENTIONS: Platelet transfusion during perioperative intensive care unit (ICU) admission. MEASUREMENTS AND MAIN RESULTS: Overall, 12,043 adults met the study inclusion criteria. Of these, 1,621 (13.5%) received apheresis-leukoreduced platelets, with a median of 1.19 units per recipient (IQR: 0.93-1.19) at a median of 1.78 hours (IQR: 0.75-4.25) after ICU admission. The platelet count was measured in 1,176 patients (72.5%) before transfusion, with a median count of 120 × 109/L (IQR: 89.0-157.0), and only 53 (3.3%) had platelet counts below 50 × 109/L. After propensity matching of 1,046 platelet recipients with 1,046 controls, perioperative platelet transfusion carried no association with in-hospital mortality (odds ratio [OR]: 1.28; 99% CI: 0.49-3.35; p = 0.4980). However, it was associated with a pattern of decreased odds of suspected infection (eg, respiratory infection, urinary tract infection, septicaemia, or other; OR: 0.70; 99% CI: 0.50-0.97; p = 0.0050), days in the hospital (adjusted mean difference [AMD]: 0.86; 99% CI: -0.27 to 1.98; p = 0.048), or days in intensive care (AMD 0.83; 99% CI: -0.15 to 1.82; p = 0.0290). CONCLUSIONS: Platelet transfusion was not associated with hospital mortality, but it was associated with decreased odds of suspected infection and with shorter ICU and hospital stays.

Cryoprecipitate Transfusion After Cardiac Surgery.

OBJECTIVES: The association of cryoprecipitate transfusion with patient outcomes after cardiac surgery is unclear. We aimed to investigate the predictors of, and outcomes associated with, postoperative cryoprecipitate transfusion in cardiac surgery patients. METHODS: We used the Medical Information Mart for Intensive Care III and IV databases. We included adults undergoing cardiac surgery, and propensity score matched cryoprecipitate-treated patients to controls. Using the matched cohort, we investigated the association of cryoprecipitate use with clinical outcomes. The primary outcome was in-hospital mortality. Secondary outcomes were infection, acute kidney injury, intensive care unit length of stay, hospital length of stay, and chest tube output at 2-hour intervals. RESULTS: Of 12,043 eligible patients, 283 (2.35%) patients received cryoprecipitate. The median dose was 5.83 units (IQR 4.17-7.24) given at a median first transfusion time of 1.75 hours (IQR 0.73-4.46) after intensive care unit admission. After propensity scoring, we matched 195 cryoprecipitate recipients to 743 controls. Postoperative cryoprecipitate transfusion was not significantly associated with in-hospital mortality (odds ratio [OR] 1.10; 99% confidence interval [CI] 0.43-2.84; p=0.791), infection (OR 0.77; 99% CI 0.45-1.34; p=0.220), acute kidney injury (OR 1.03; 99% CI 0.65-1.62; p=0.876) or cumulative chest tube output (adjusted mean difference 8 hrs post transfusion, 11 mL; 99% CI -104 to 125; p=0.804). CONCLUSIONS: Although cryoprecipitate was typically given to sicker patients with more bleeding, its administration was not associated with worse outcomes. Large, multicentred studies are warranted to further elucidate cryoprecipitate's safety profile and patterns of use in cardiac surgery.

Troponin as a predictor of outcomes in transcatheter aortic valve implantation: systematic review and meta-analysis.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is emerging as a therapeutic gold standard in the management of aortic stenosis. However, post-procedural complications of this procedure are being increasingly recognised. We therefore performed this systematic review and meta-analysis on the prognostic value of elevated troponin prior to TAVI to predict risk of post-procedural complications. METHODS: We searched Medline (Ovid), Embase (Ovid), and the Cochrane Library from inception until May 2022, and included studies on the association between elevated pre-procedural troponin with 30-day mortality, long-term mortality, and post-procedural myocardial injury (PPMI). We generated summary odds ratios (OR) and hazards ratios (HR) using random-effects meta-analysis and performed subgroup analyses to evaluate differences in troponin threshold selection. Inter-study heterogeneity was tested using the I2 test. RESULTS: We included 10 studies involving 4200 patients. Serum troponin elevation prior to TAVI was significantly associated with long-term mortality [HR = 2.09 (95% CI 1.30-3.36)], but not with 30-day mortality [OR 1.76 (95% CI 0.96-3.22)]. Subgroup analysis showed a trend towards increased effect size and statistical significance for 30-day mortality as troponin elevation was more narrowly defined. Two studies reported on PPMI and found no statistically significant mean difference between groups. CONCLUSIONS: Raised serum troponin is associated with increased long-term mortality following TAVI. Further clarification on the optimal troponin threshold for risk identification is required. High-quality studies that utilise ROC analysis for threshold selection are warranted.

Perioperative gabapentinoid use lowers short-term opioid consumption following lower limb arthroplasty: Systematic review and meta-analysis.

BACKGROUND: The management of post-operative pain and high levels of acute and chronic opioid use following total knee arthroplasty (TKA) and total hip arthroplasty (THA) remain challenges to the perioperative team. We performed a system-atic review and meta-analysis to determine the opioid sparing effects, analgesic effects, and safety profile of perioperative gabapentinoid usage in lower limb arthroplasty. METHODS: We searched multiple databases from inception until May 2019 and included randomized controlled trials (RCT) on perioperative gabapentinoids in lower limb arthroplasty. The primary outcome was cumulative opioid con-sumption (oral morphine equivalents) at 24 and 48 hours, and the secondary outcomes were pain scores, time to hospi-tal discharge, and adverse events including nausea, vomiting, pruritus, and sedation. Methodological quality was as-sessed using the Cochrane tool. The grading of recommendations assessment, development, and evaluation method-ology for the certainty of evidence was also used. RESULTS: We included 19 RCT involving 2,455 patients undergoing lower limb arthroplasty. The overall methodological quality of included studies was good. Gabapentinoid use was associated with a significant reduction in opioid consump-tion at 24 hour (mean difference (MD) 22.81 mg [95 percent Confidence Interval (CI) 13.64-31.98]) and 48 hour (MD 44.03 mg [95 percent CI 16.92-71.14]). We found no meaningful difference in pain scores at rest between gabapenti-noid and placebo groups at 24 or 48 hours. Gabapentinoid use reduced the risk of post-operative nausea (risk ratio (RR) 0.69 [95 percent CI 0.57-0.82]), vomiting (RR 0.65 [95 percent CI 0.47-0.91]), and pruritus (RR 0.60 [0.37-0.98]), but not sedation (RR 1.25 [0.76-2.06]). There was no effect on time to discharge from hospital (MD-0.05 days [95 per-cent CI -0.31 to 0.20]. CONCLUSIONS: The addition of gabapentinoids to perioperative multimodal analgesia decreases opioid consumption fol-lowing lower limb arthroplasty, while also lowering rates of nausea, vomiting, and pruritus. Further study is required to evaluate the effect of gabapentinoid use on long-term opioid use and dependence.

Machine Learning Outperforms Existing Clinical Scoring Tools in the Prediction of Postoperative Atrial Fibrillation During Intensive Care Unit Admission After Cardiac Surgery.

OBJECTIVE(S): Using the Medical Information Mart for Intensive Care III (MIMIC-III) database, we compared the performance of machine learning (ML) to the to the established gold standard scoring tool (POAF Score) in predicting postoperative atrial fibrillation (POAF) during intensive care unit (ICU) admission after cardiac surgery. METHODS: Random forest classifier (RF), decision tree classifier (DT), logistic regression (LR), K neighbours classifier (KNN), support vector machine (SVM), and gradient boosted machine (GBM) were compared to the POAF Score. Cross-validation was used to assess the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of ML models. POAF Score performance confidence intervals were generated using 1,000 bootstraps. Risk profiles for GBM were generated using Shapley additive values. RESULTS: A total of 6,349 ICU admissions encompassing 6,040 patients were included. POAF occurred in 1,364 of the 6,349 admissions (21.5%). For predicting POAF during ICU admission after cardiac surgery, GBM, LR, RF, KNN, SVM and DT achieved an AUC of 0.74 (0.71-0.77), 0.73 (0.71-0.75), 0.72 (0.69-0.75), 0.68 (0.67-0.69), 0.67 (0.66-0.68) and 0.59 (0.55-0.63) respectively. The POAF Score AUC was 0.63 (0.62-0.64). Shapley additive values analysis of GBM generated patient level explanations for each prediction. CONCLUSION: Machine learning models based on readily available preoperative data can outperform clinical scoring tools for predicting POAF during ICU admission after cardiac surgery. Explanatory models are shown to have potential in personalising POAF risk profiles for patients by illustrating probabilistic input variable contributions. Future research is required to evaluate the clinical utility and safety of implementing ML-driven tools for POAF prediction.

Duration of post-operative antibiotic treatment in acute complicated appendicitis: systematic review and meta-analysis.

BACKGROUND: Appendicitis is the most frequent aetiology of acute abdominal pain requiring surgical treatment, with an estimated lifetime risk between 7% and 8%. Antibiotics play a substantial role in treatment, and there is considerable debate regarding the duration of antibiotics in treating appendicitis. METHODS: We searched multiple databases from inception until June 2019 for peer-reviewed studies that compared different durations of antibiotic treatment after appendicectomy for acute complicated appendicitis in adults. We dichotomized reported data into short- and extended-term antibiotic use and controlled for different definitional thresholds in the meta-analysis. We generated risk ratios using restricted maximum likelihood methods and mixed effects modelling for each outcome of interest. RESULTS: Four observational studies involving 847 participants were included in the meta-analysis. For the primary outcomes of intra-abdominal infection, we did not find a statistically significant difference between extended- and short-term antibiotic strategies for intra-abdominal infection (Risk ratio 0.92, 95% confidence interval (CI) 0.49-1.74). Three randomized controlled trials involving 291 participants were included in a separate meta-analysis. We found that extended antibiotic usage was not associated with a statistically significant reduced risk for intra-abdominal infection (RR 0.52, 95% CI 0.21-1.29) or surgical site skin infection (RR 1.44, 95% CI 0.43-4.81). CONCLUSION: This systematic review and meta-analysis found that extended post-operative antibiotic treatment may not be associated with a reduced risk of intra-abdominal infection; however, meta-analysis was significantly limited by heterogeneity between studies and underpowered trials. Further large randomized controlled trials are needed to confirm these findings.

Prognostic Significance of Preoperative Neutrophil-Lymphocyte Ratio in Vascular Surgery: Systematic Review and Meta-Analysis.

OBJECTIVE: The global burden of surgical vascular disease is increasing and with it, the need for cost-effective, accessible prognostic biomarkers to aid optimization of peri-operative outcomes. The neutrophil-lymphocyte ratio (NLR) is emerging as a potential candidate biomarker for perioperative risk stratification. We therefore performed this systematic review and meta-analysis on the prognostic value of elevated preoperative NLR in vascular surgery. METHODS: We searched Embase (Ovid), Medline (Ovid), and the Cochrane Library database from inception to June 2019. Screening was performed, and included all peer-reviewed original research studies reporting preoperative NLR in adult emergent and elective vascular surgical patients. Studies were assessed for bias and quality of evidence using a standardized tool. Meta-analysis was performed by general linear (mixed-effects) modelling where possible, and otherwise a narrative review was conducted. Between-study heterogeneity was estimated using the Chi-squared statistic and explored qualitatively. RESULTS: Fourteen studies involving 5,652 patients were included. The overall methodological quality was good. Elevated preoperative NLR was associated with increased risk of long-term mortality (HR 1.40 [95%CI: 1.13-1.74], Chi-squared 60.3%, 7 studies, 3,637 people) and short-term mortality (OR: 3.08; 95%CI: 1.91-4.95), Chi-squared 66.59%, 4 studies, 945 people). Outcome measures used by fewer studies such as graft patency and amputation free survival were assessed via narrative review. CONCLUSIONS: NLR is a promising, readily obtainable, prognostic biomarker for mortality outcomes following vascular surgery. Heterogeneity in patient factors, severity of vascular disease, and type of vascular surgery performed renders direct comparison of outcomes from the current literature challenging. This systematic review supports further investigation for NLR measurement in pre-vascular surgical risk stratification. In particular, the establishment of a universally accepted NLR cut-off value is of importance in real-world implementation of this biomarker.

Systematic review and meta-analysis of postoperative troponin as a predictor of mortality and major adverse cardiac events after vascular surgery.

BACKGROUND: The prognostic value of asymptomatic perioperative troponin rise in vascular surgery is unclear. We conducted this systematic review and meta-analysis to determine the significance of clinical and subclinical troponin elevation after vascular surgery. METHODS: We searched MEDLINE (Ovid), Embase (Ovid), and the Cochrane Library, without language restriction, from inception to May 2019 and included studies that reported associations between elevated postoperative troponin and short-term mortality, major adverse cardiac events (MACEs), or long-term mortality in a vascular surgery cohort. We synthesized study-level data on the maximally adjusted estimates using mixed effects modeling to generate summary odds ratios (ORs) for fixed-interval outcomes and summary hazard ratios for long-term mortality. Between-study heterogeneity was assessed with meta-regression. Methodologic quality and publication bias were formally assessed. RESULTS: We included 24 studies involving 11,657 participants. Postoperative troponin was found to have a strong, positive association with short-term mortality (OR, 4.95; 95% confidence interval [CI], 2.87-8.52; 7 studies; 2661 people) and MACEs (OR, 5.33; 95% CI, 1.59-17.82; 12 studies; 5047 people) independent of meeting the criteria for myocardial infarction. Subclinical postoperative troponin elevation was further demonstrated to be associated with greater long-term mortality (hazard ratio, 1.94; 95% CI, 1.56-2.42; 13 studies; 7630 people; median follow-up, 24 months). Time to troponin sampling, hypertension, and type of surgery partially accounted for between-study heterogeneity. The methodologic quality of included studies was variable, and publication bias was not detected. CONCLUSIONS: Elevated postoperative troponin is strongly prognostic of worse survival and greater likelihood of MACEs after vascular surgery, regardless of whether symptoms of myocardial ischemia are present. These data support the benefit of postoperative troponin monitoring in identifying patients at increased risk of worse outcomes and who may be candidates for personalized preventive interventions.

The Prognostic Value of Elevated Perioperative Neutrophil-Lymphocyte Ratio in Predicting Postoperative Atrial Fibrillation After Cardiac Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: The neutrophil-lymphocyte ratio (NLR) is an emerging inflammatory perioperative biomarker which has been studied to predict the incidence of postoperative atrial fibrillation (POAF) after cardiac surgery. This systematic review and meta-analysis aimed to evaluate the prognostic accuracy of elevated perioperative NLR in predicting POAF after cardiac surgery. METHODS: Multiple databases were searched from inception to May 2019 for prognostic studies on perioperative NLR and POAF following cardiac surgery. Maximally adjusted odds ratios (OR) with associated confidence intervals were obtained from each included study and pooled using random effects inverse variance modelling for preoperative NLR measurements, while standardised mean differences were pooled for postoperative NLR values. The significance of inter- and intra-study heterogeneity was explored using meta-regression. RESULTS: 1,799 unique studies satisfied selection criteria, from which 12 studies incorporating 9,262 participants were included. Elevated preoperative NLR significantly predicted POAF, with a pooled OR of 1.42 (95% CI 1.16-1.72). Multiple predefined covariates contributed to inter-study heterogeneity; however, only prevalence of hypertension (p=0.0055), history of congestive cardiac failure (p=0.0282) and average ejection fraction (p=0.0359) were significant effect modifiers. Elevated postoperative NLR was not a significant predictor of POAF (standardised mean difference 1.60 [95% CI -0.56-3.77] between POAF+ and POAF- groups). CONCLUSIONS: Elevated preoperative NLR is a promising prognostic biomarker for POAF, but residual sources of heterogeneity remain. Larger scale validation studies are required to justify the integration of preoperative NLR testing into routine clinical practice.