Impact of haemoglobin concentration on cardiovascular outcome after vascular surgery: A retrospective observational cohort study

Clinical Outcomes of 5000 IU Heparin Versus Activated Clotting Time-Guided Heparinization During Noncardiac Arterial Procedures: A Propensity Score Matched Analysis

PURPOSE

Previous studies have shown that activated clotting time (ACT)-guided heparinization leads to better anticoagulation levels during noncardiac arterial procedures (NCAP) than a standardized bolus of 5000 IU. Better anticoagulation should potentially result in lower incidence of thrombo-embolic complications (TEC). Comparative investigations on clinical outcomes of these heparinization strategies are scarce. This study investigated clinical outcomes of ACT-guided heparinization with a starting dose of 100 IU/kg in comparison with a single standardized bolus of 5000 IU heparin during NCAP.

MATERIALS AND METHODS

Analysis from a prospectively collected database of patients undergoing NCAP in 2 vascular centers was performed. Patients receiving ACT-guided heparinization were matched 1:1 with patients receiving 5000 IU heparin using propensity score matching (PSM). Primary outcomes were TEC, bleeding complications, and mortality within 30 days of procedure or during the same admission.

RESULTS

A total of 759 patients (5000 IU heparin: 213 patients, ACT-guided heparinization: 546 patients) were included. Propensity score matching resulted in 209 patients in each treatment group. After PSM, the groups were comparable, with the exception of a higher prevalence of peripheral arterial disease in the ACT-guided heparinization group (103 patients, 49% vs 82 patients, 39%, p=0.039). The target ACT (>200 seconds) was reached in 198 patients (95%) of the ACT-guided group versus 71 patients (34%) of the 5000 IU group (p<0.001), indicating successful execution of the ACT-guided protocol. Incidence of TEC (13 patients, 6.2% vs 10 patients, 4.8%, p=0.52), mortality (3 patients, 1.4% vs 0 patients, p=0.25), and bleeding complications (32 patients, 15% vs 25 patients, 12%, p=0.32) did not differ between patients receiving ACT-guided heparinization and 5000 IU heparin. Protamine was administered in 118 patients (57%) in the ACT group versus 11 patients (5.3%) in the 5000 IU group (p<0.001), but did not influence incidence of TEC (17 patients, 5.9% vs 6 patients, 4.7%, p=0.61) or bleeding complications (34 patients, 12% vs 22 patients, 17%, p=0.14).

CONCLUSION

No difference in TEC, bleeding complications, or mortality was found between ACT-guided heparinization and a single bolus of 5000 IU heparin during NCAP.

CLINICAL IMPACT

Previous studies have shown that activated clotting time (ACT)-guided heparinization leads to better anticoagulation levels during non-cardiac arterial procedures (NCAP) then a standardized bolus of 5000 IU. Comparative investigations on clinical outcomes are scarce. This study focussed on clinical outcomes of both protocols in NCAP in a propensity score matched cohort. Thrombo-embolic complications (TEC), bleeding complications and mortality within 30 days after NCAP or during the same admission were comparable between groups. Future studies should focus on optimizing ACT-guided protocols, specifically in patients with a high risk of TEC and bleeding complications.

Perioperative transfusion study (PETS): Does a liberal transfusion protocol improve outcome in high-risk cardiovascular patients undergoing non-cardiac surgery? A randomised controlled pilot study

BACKGROUND

Small studies have shown that patients with advanced coronary artery disease might benefit from a more liberal blood transfusion strategy. The goal of this pilot study was to test the feasibility of a blood transfusion intervention in a group of vascular surgery patients who have elevated cardiac troponins in rest.

METHODS

We conducted a single-centre, randomised controlled pilot study. Patients with a preoperative elevated high-sensitive troponin T undergoing non-cardiac vascular surgery were randomised between a liberal transfusion regime (haemoglobin >10.4 g/dL) and a restrictive transfusion regime (haemoglobin 8.0-9.6 g/dL) during the first 3 days after surgery. The primary outcome was defined as a composite endpoint of all-cause mortality, myocardial infarction or unscheduled coronary revascularization.

RESULTS

In total 499 patients were screened; 92 were included and 50 patients were randomised. Postoperative haemoglobin was different between the intervention and control group; 10.6 versus 9.8, 10.4 versus 9.4, 10.9 versus 9.4 g/dL on day one, two and three respectively (p < 0.05). The primary outcome occurred in four patients (16%) in the liberal transfusion group and in two patients (8%) in control group.

CONCLUSION

This pilot study shows that the studied transfusion protocol was able to create a clinically significant difference in perioperative haemoglobin levels. Randomisation was possible in 10% of the screened patients. A large definitive trial should be possible to provide evidence whether a liberal transfusion strategy could decrease the incidence of postoperative myocardial infarction in high risk surgical patients.

Investigation on the relationship between hemoglobin concentration and stroke risk: a bidirectional Mendelian randomization study

Background

The relationship between hemoglobin concentration and stroke has garnered significant interest in the research community. However, findings from published observational epidemiological studies on this relationship have been inconclusive. By using publicly available genome-wide association study (GWAS) aggregated statistics, a two-sample Mendelian randomization analysis is conducted to explore the causal relationship between hemoglobin concentration and stroke.

Methods

Summary statistics data from UK Biobank for hemoglobin concentration and from the FinnGen R9 and MEGASTROKE consortium for stroke are used. A series of quality control steps are taken to select eligible instrumental SNPs closely related to exposure. In order to make the conclusion more robust and reliable, several robust analysis methods are employed including inverse variance weighted, weighted median, MR-Egger regression, which are based on different assumptions of two-sample MR Analysis. Meanwhile, sensitivity analyses such as pleiotropy test and MR-Egg regression, are performed to mitigate horizontal pleiotropy and heterogeneity.

Results

The two-sample Mendelian randomized study indicates a negative association between hemoglobin concentration and stroke, suggesting that hemoglobin concentration acts as a protective factor against stroke. From the FinnGen database, there is a negative association between hemoglobin concentration and stroke, with an odds ratio (OR) of 0.82 and a 95% confidence interval (CI) of 0.73-0.92, p = 0.0006. Similarly, the MEGASTROKE database findings reinforce this observation. The negative association between hemoglobin concentration and stroke (OR: 0.91, 95%CI: 0.83-1.00, p = 0.040), ischemic stroke (OR: 0.87, 95%CI: 0.79-0.96, p = 0.004), and cardiogenic stroke (OR: 0.82, 95% CI: 0.69-0.99, p = 0.039) further suggests that higher hemoglobin levels might confer a protective effect against these conditions.

Conclusion

Hemoglobin concentration serves as a protective factor against stroke, and managing abnormal hemoglobin levels can effectively reduce the incidence of stroke.

Myocardial Injury Is Associated with the Incidence of Major Adverse Cardiac Events in Patients with Severe Trauma

BACKGROUND

Severe trauma potentially results in end-organ damage such as myocardial injury. Data suggest that myocardial injury is associated with increased mortality in this cohort, but the association with the incidence of in-hospital major adverse cardiac events (MACE) remains undetermined.

METHODS

Retrospective cohort study including adult patients with severe trauma treated at the University Hospital Duesseldorf between January 2016 and December 2019. The main exposure was myocardial injury at presentation. Endpoints were in-hospital incidence of MACE and incidence of acute kidney injury (AKI) within 72 h. Discrimination of hsTnT for MACE and AKI was examined by the receiver operating characteristic curve (ROC) and the area under the curve (AUC). We conducted multivariate logistic regression analysis.

RESULTS

We included 353 patients in our final analysis (72.5% male (256/353), age: 55 ± 21 years). The AUC for hsTnT and MACE was 0.68 [95% confidence interval (CI): 0.59-0.78]. The AUC for hsTnT and AKI was 0.64 [95% (CI): 0.55-0.72]. The adjusted odds ratio (OR) for myocardial injury and MACE was 2.97 [95% (CI): 1.31-6.72], and it was 2.14 [95% (CI): 1.03-4.46] for myocardial injury and AKI.

CONCLUSION

Myocardial injury at presentation in patients with severe trauma is independently associated with the incidence of in-hospital MACE and AKI.

The comparative and added prognostic value of biomarkers to the Revised Cardiac Risk Index for preoperative prediction of major adverse cardiac events and all-cause mortality in patients who undergo noncardiac surgery

BACKGROUND

The Revised Cardiac Risk Index (RCRI) is a widely acknowledged prognostic model to estimate preoperatively the probability of developing in-hospital major adverse cardiac events (MACE) in patients undergoing noncardiac surgery. However, the RCRI does not always make accurate predictions, so various studies have investigated whether biomarkers added to or compared with the RCRI could improve this.

OBJECTIVES

Primary: To investigate the added predictive value of biomarkers to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery. Secondary: To investigate the prognostic value of biomarkers compared to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery. Tertiary: To investigate the prognostic value of other prediction models compared to the RCRI to preoperatively predict in-hospital MACE and other adverse outcomes in patients undergoing noncardiac surgery.

SEARCH METHODS

We searched MEDLINE and Embase from 1 January 1999 (the year that the RCRI was published) until 25 June 2020. We also searched ISI Web of Science and SCOPUS for articles referring to the original RCRI development study in that period.

SELECTION CRITERIA

We included studies among adults who underwent noncardiac surgery, reporting on (external) validation of the RCRI and: - the addition of biomarker(s) to the RCRI; or - the comparison of the predictive accuracy of biomarker(s) to the RCRI; or - the comparison of the predictive accuracy of the RCRI to other models. Besides MACE, all other adverse outcomes were considered for inclusion.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form based on the CHARMS checklist. Independent pairs of authors screened references, extracted data and assessed risk of bias and concerns regarding applicability according to PROBAST. For biomarkers and prediction models that were added or compared to the RCRI in ≥ 3 different articles, we described study characteristics and findings in further detail. We did not apply GRADE as no guidance is available for prognostic model reviews.

MAIN RESULTS

We screened 3960 records and included 107 articles.   Over all objectives we rated risk of bias as high in ≥ 1 domain in 90% of included studies, particularly in the analysis domain. Statistical pooling or meta-analysis of reported results was impossible due to heterogeneity in various aspects: outcomes used, scale by which the biomarker was added/compared to the RCRI, prediction horizons and studied populations.  Added predictive value of biomarkers to the RCRI Fifty-one studies reported on the added value of biomarkers to the RCRI. Sixty-nine different predictors were identified derived from blood (29%), imaging (33%) or other sources (38%). Addition of NT-proBNP, troponin or their combination improved the RCRI for predicting MACE (median delta c-statistics: 0.08, 0.14 and 0.12 for NT-proBNP, troponin and their combination, respectively). The median total net reclassification index (NRI) was 0.16 and 0.74 after addition of troponin and NT-proBNP to the RCRI, respectively. Calibration was not reported. To predict myocardial infarction, the median delta c-statistic when NT-proBNP was added to the RCRI was 0.09, and 0.06 for prediction of all-cause mortality and MACE combined. For BNP and copeptin, data were not sufficient to provide results on their added predictive performance, for any of the outcomes. Comparison of the predictive value of biomarkers to the RCRI  Fifty-one studies assessed the predictive performance of biomarkers alone compared to the RCRI. We identified 60 unique predictors derived from blood (38%), imaging (30%) or other sources, such as the American Society of Anesthesiologists (ASA) classification (32%). Predictions were similar between the ASA classification and the RCRI for all studied outcomes. In studies different from those identified in objective 1, the median delta c-statistic was 0.15 and 0.12 in favour of  BNP and NT-proBNP alone, respectively, when compared to the RCRI, for the prediction of MACE. For C-reactive protein, the predictive performance was similar to the RCRI. For other biomarkers and outcomes, data were insufficient to provide summary results. One study reported on calibration and none on reclassification. Comparison of the predictive value of other prognostic models to the RCRI   Fifty-two articles compared the predictive ability of the RCRI to other prognostic models. Of these, 42% developed a new prediction model, 22% updated the RCRI, or another prediction model, and 37% validated an existing prediction model. None of the other prediction models showed better performance in predicting MACE than the RCRI. To predict myocardial infarction and cardiac arrest, ACS-NSQIP-MICA had a higher median delta c-statistic of 0.11 compared to the RCRI. To predict all-cause mortality, the median delta c-statistic was 0.15 higher in favour of ACS-NSQIP-SRS compared to the RCRI. Predictive performance was not better for CHADS₂, CHA₂DS₂-VASc, R₂CHADS₂, Goldman index, Detsky index or VSG-CRI compared to the RCRI for any of the outcomes. Calibration and reclassification were reported in only one and three studies, respectively.

AUTHORS' CONCLUSIONS

Studies included in this review suggest that the predictive performance of the RCRI in predicting MACE is improved when NT-proBNP, troponin or their combination are added. Other studies indicate that BNP and NT-proBNP, when used in isolation, may even have a higher discriminative performance than the RCRI. There was insufficient evidence of a difference between the predictive accuracy of the RCRI and other prediction models in predicting MACE. However, ACS-NSQIP-MICA and ACS-NSQIP-SRS outperformed the RCRI in predicting myocardial infarction and cardiac arrest combined, and all-cause mortality, respectively. Nevertheless, the results cannot be interpreted as conclusive due to high risks of bias in a majority of papers, and pooling was impossible due to heterogeneity in outcomes, prediction horizons, biomarkers and studied populations. Future research on the added prognostic value of biomarkers to existing prediction models should focus on biomarkers with good predictive accuracy in other settings (e.g. diagnosis of myocardial infarction) and identification of biomarkers from omics data. They should be compared to novel biomarkers with so far insufficient evidence compared to established ones, including NT-proBNP or troponins. Adherence to recent guidance for prediction model studies (e.g. TRIPOD; PROBAST) and use of standardised outcome definitions in primary studies is highly recommended to facilitate systematic review and meta-analyses in the future.

Peripheral arterial disease and anaemia. A review

Iron deficiency anaemia is highly prevalent worldwide. In the surgical patient, anaemia of any cause implies higher morbidity and mortality in the post-operative period. This is especially important in patients with peripheral artery disease, as they have very high rates of anaemia due to iron deficiency or other causes. In intermittent claudication, anaemia is a predictor of death in the medium term. Patients with critical ischaemia have higher prevalence of anaemia and it is an indicator of amputation and death in the medium term. Specific protocols need to be developed for these patients since the natural history of their disease does not allow for the correction of anaemia before surgery.

Perioperative pharmacotherapy to prevent cardiac complications in patients undergoing noncardiac surgery

Introduction: Despite advances in surgical and anesthetic techniques, perioperative cardiovascular complications are a major cause of 30-day perioperative mortality. Major cardiovascular complications after noncardiac surgery include myocardial ischemia, congestive heart failure, arrhythmias, and cardiac arrest. Along with surgical risk assessment, perioperative medical optimization can reduce the rates and clinical impact of these complications.Areas Covered: In this review, the authors discuss the pharmacological basis, existing evidence, and professional society recommendations for drug management in preventing cardiovascular complications in patients undergoing noncardiac surgery.Expert opinion: Perioperative management of cardiovascular disease is an increasingly important and growing area of clinical practice. Societal guidelines regarding the use of most routine cardiovascular medications are based on a number of large clinical studies and provide a basic foundation to guide management. However, the heterogeneous nature of patients, as well as surgeries, makes it practically impossible to devise a 'one size fits all' recommendation in this setting. Thus, the importance of a more individualized approach to perioperative risk stratification and management is being increasingly recognized. The underlying comorbidities and cardiac profile as well as the risk of cardiac complications associated with the planned surgery must be factored in to understand the nuance of the management strategies.

Troponin I as a mortality marker after lung resection surgery - a prospective cohort study

BACKGROUND

Cardiovascular complications associated with thoracic surgery increase morbidity, mortality, and treatment costs. Elevated cardiac troponin level represents a predictor of complications after non-cardiac surgeries, but its role after thoracic surgeries remains undetermined. The objective of this study was to analyze the relationship between troponin I elevation and morbidity and mortality after one year in patients undergoing lung resection surgery.

METHODS

This prospective cohort study evaluated 151 consecutive patients subjected to elective lung resection procedures using conventional and video-assisted thoracoscopic techniques at a University Hospital in Brazil, from July 2012 to November 2015. Preoperative risk stratification was performed using the scores obtained by the American College of Physicians (ACP) and the Society of Cardiology of the state of São Paulo (EMAPO) scoring systems. Troponin I levels were measured in the immediate postoperative period (POi) and on the first and second postoperative days.

RESULTS

Most patients had a low risk for complications according to the ACP (96.7%) and EMAPO (82.8%) scores. Approximately 49% of the patients exhibited increased troponin I (≥0.16 ng/ml), at least once, and 22 (14.6%) died in one year. Multivariate analysis showed that the elevation of troponin I, on the first postoperative day, correlated with a 12-fold increase in mortality risk within one year (HR 12.02, 95% CI: 1.82-79.5; p = 0.01).

CONCLUSIONS

In patients undergoing lung resection surgery, with a low risk of complications according to the preoperative evaluation scores, an increase in troponin I levels above 0.16 ng/ml in the first postoperative period correlated with an increase in mortality within one year.

Causes and prevention of postoperative myocardial injury

Over the past few years non-cardiac surgery has been recognised as a serious circulatory stress test which may trigger cardiovascular events such as myocardial infarction, in particular in patients at high risk. Detection of these postoperative cardiovascular events is difficult as clinical symptoms often go unnoticed. To improve detection, guidelines advise to perform routine postoperative assessment of cardiac troponin. Troponin elevation - or postoperative myocardial injury - can be caused by myocardial infarction. However, also non-coronary causes, such as cardiac arrhythmias, sepsis and pulmonary embolism, may play a role in a considerable number of patients with postoperative myocardial injury. It is crucial to acquire more knowledge about the underlying mechanisms of postoperative myocardial injury because effective prevention and treatment options are lacking. Preoperative administration of beta-blockers, aspirin, statins, clonidine, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, and preoperative revascularisation have all been investigated as preventive options. Of these, only statins should be considered as the initiation or reload of statins may reduce the risk of postoperative myocardial injury. There is also not enough evidence for intraoperative measures such blood pressure optimisation or intensified medical therapy once patients have developed postoperative myocardial injury. Given the impact, better preoperative identification of patients at risk of postoperative myocardial injury, for example using preoperatively measured biomarkers, would be helpful to improve cardiac optimisation.

Troponin elevations after non-cardiac, non-vascular surgery are predictive of major adverse cardiac events and mortality: a systematic review and meta-analysis

BACKGROUND

Patients undergoing non-cardiac, non-vascular surgery are at risk of major cardiovascular complications. In non-cardiac surgery, troponin elevation has previously been shown to be an independent predictor of major adverse cardiac events and postoperative mortality; however, a majority of studies have focused on vascular surgery patients. The aim of this meta-analysis was to determine whether troponin elevation is a predictor of major adverse cardiac events and mortality within 30 days and 1 yr after non-cardiac, non-vascular surgery.

METHODS

A systematic review and meta-analysis was conducted in January 2016 according to the Meta-analysis Of Observational Studies in Epidemiology guidelines. Both interventional and observational studies measuring troponin within the first 4 days after surgery were eligible. A systematic search was performed in PubMed, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials.

RESULTS

Eleven eligible clinical studies (n=2193) were identified. A postoperative troponin elevation was a predictor of 30 day mortality, odds ratio (OR) 3.52 [95% confidence interval (CI) 2.21-5.62; I²=0%], and an independent predictor of 1 yr mortality, adjusted OR 2.53 (95% CI 1.20-5.36; I²=26%). A postoperative troponin elevation was associated with major adverse cardiac events at 30 days, OR 5.92 (95% CI 1.67-20.96; I²=86%), and 1 yr after surgery, adjusted OR 3.00 (95% CI 1.43-6.29; I²=21%).

CONCLUSIONS

Postoperative myocardial injury is an independent predictor of major adverse cardiac events and mortality within 30 days and 1 yr after non-cardiac, non-vascular surgery. The meta-analysis provides evidence that supports troponin monitoring as a cardiovascular risk stratification tool.