Postoperative Troponin Research Articles

Postoperative Cardiac Troponin I Thresholds Associated With 1-Year Cardiac Mortality After Adult Cardiac Surgery: An Attempt to Link Risk Stratification With Management Stratification in an Observational Study

Cardiac troponin (cTn) concentrations are measured routinely in some centers after cardiac surgery as part of risk stratification, but there are no data on how increased cTn concentrations could change patients' management. The aim of this study was to estimate relevant cTnI thresholds and identify potential interventions (additional monitoring/therapeutic interventions) that could be part of management changes of patients with cTnI greater than relevant thresholds. Retrospective, single-center, observational study. Bichat-Claude Bernard Hospital, Paris, France, between January 1, 2009, and December 31, 2012. Consecutive adult patients undergoing cardiac surgery. cTnI was measured on the 20th postoperative hour. Causes of death and possible interventions were determined by analysis of individual medical records. cTnI thresholds for 1-year cardiac mortality with a specificity >80% were calculated. For this study, 3,228 procedures were analyzed; 129 deaths occurred (4%), 83 of which (2.6%) were cardiac deaths. Threshold cTnI values were 4.2 µg/L for coronary artery bypass grafting (95% confidence interval [CI] 3.9-4.5) and 10.7 µg/L for non-coronary artery bypass grafting (95% CI 10.0-11.3). In multivariable analysis, the EuroSCORE II (odds ratio 1.1 [95% CI 1.06-1.13]; p < 0.001) and cTnI concentrations greater than the thresholds (odds ratio 5.62 [95% CI 3.37-9.37]; p < 0.001) were associated with significantly increased risk of death. The additive and absolute Net Reclassification Index were 0.288% and 14.1%, respectively, for a logistic model including cTnI and EuroSCORE II (area under the curve C-index 0.82 [95% CI 0.77-0.87]) compared with a model including only EuroSCORE II (area under the curve C-index 0.80 [95% CI 0.75-0.84]). Fifty-three of the 83 patients who experienced cardiac death (64%) had a cTnI concentration greater than the threshold, and an intervention was deemed possible in 47 of those 53 (89%) (mostly patients with mild postoperative cardiac dysfunction). For noncardiac deaths, 28% of patients had a cTnI concentration greater than the threshold and no interventions were deemed possible. In an attempt to evolve from risk to management stratification, this study's results identified a subgroup of patients with mild cardiac dysfunction and a cTnI concentration greater than the threshold who could be the target for interventions in future validation studies concerning changes in patient management.

The del Nido versus cold blood cardioplegia in aortic valve replacement: A randomized trial

ObjectivesTo compare the cardioprotective efficacy of a solution that requires only a single infusion at the start of the ischemic duration versus a solution that requires multiple infusions. MethodsAortic valve replacement was performed for 150 patients, who were randomized into the del Nido (DN) cardioplegia group or the cold blood (CB) cardioplegia group. The DN cardioplegia was delivered every 90 minutes and the CB cardioplegia was delivered every 20 to 30 minutes, or whenever cardiac activity was observed. The primary endpoints were electrical cardiac activity during crossclamp, ventricular fibrillation during reperfusion, and postoperative troponin and creatine kinase (CK-MB isoenzyme) at 24 and 48 hours. ResultsElectrical activity during crossclamp occurred in 29 (39.7%) patients in the DN group versus 34 (45.3%) patients in the CB group (adjusted P = 1.0). The number of procedures with ventricular fibrillation after removing the crossclamp was 41 (54.7%) in the CB group versus 17 (22.7%) in the DN group (adjusted P = .001; relative risk, 2.41). Troponin values appeared to be lower in the DN group (median, 223.10; interquartile range, 168.35-364.77 pg/mL vs 285.5; 196.20-419.45 pg/mL at 24 hours and 159.60; 125.42-217.20 pg/mL vs 201.60; 160.62-268.45 pg/mL at 48 hours) and CK-MB (median, 14.94; interquartile range, 12.16-20.39 ng/mL vs 17.43; 13.66-22.43 ng/mL at 24 hours and 6.19; 4.41-7.63 ng/mL vs 7.38; 4.74-10.20 ng/mL at 48 hours), but no significance was found. ConclusionsThe del Nido cardioplegia protocol is an acceptable alternative for cold blood cardioplegia in patients undergoing aortic valve replacement.

Perioperative myocardial injury in revascularized coronary patients who undergo noncardiac surgery.

BackgroundWhether high-sensitivity cardiac troponin elevation during the perioperative period is associated with poor clinical outcome in revascularized coronary patients who undergo noncardiac surgery remains unclear. We investigated the effects of perioperative troponin elevation on the long-term clinical outcomes of patients with a history of coronary revascularization.MethodsWe analyzed patients whose pre- or postoperative high-sensitivity cardiac troponin I (hs-cTnI) assay results were available. Patients were divided into two groups according to hs-cTnI levels. The patient groups were analyzed separately according to whether hs-cTnI was assessed preoperatively or postoperatively. The primary outcome was all-cause death during the follow-up period.ResultsMedian follow-up duration was 25 months (interquartile range 11–50). In the propensity-matched analysis, the risk of all-cause death during follow-up was higher in the group with elevated hs-cTnI group than in the normal group (12.7% vs 6.3%; hazard ratio [HR], 2.67; 95% confidential interval [CI], 1.04–6.82; p = 0.04). In the propensity-matched analysis of preoperative hs-cTnI levels, we found no significant difference between the groups in the rate of all-cause death (12.9% vs. 11.9%; HR, 1.06; 95% CI, 0.45–2.50; p = 0.89). In the postoperative propensity-matched analysis, all-cause death was higher in patients with elevated hs-cTnI than in those with normal levels (14.9% vs. 5.9%; HR, 2.80; 95% CI, 1.01–7.77; p = 0.048).ConclusionIn revascularized coronary patients who underwent noncardiac surgery, postoperative (but not preoperative) hs-cTnI elevation was associated with all-cause death during follow-up. Larger datasets are needed to support this finding.

Definitions of post-coronary artery bypass grafting myocardial infarction: variations in incidence and prognostic significance.

Using data from the CORONARY trial (n = 4752), we evaluated the incidence and prognostic significance of myocardial infarction (MI) applying different definitions based on peak postoperative creatine kinase-MB isoenzyme and cardiac troponin levels. We then aimed to identify the peak cardiac troponin during the first 3 postoperative days that was independently associated with a 2-fold increase in 30-day mortality. To combine different assays, we analysed cardiac troponins in multiples of their respective upper limit of normal (ULN). We identified the lowest threshold with a hazard ratio (HR) >2 for 30-day mortality independent of EuroSCORE and on- versus off-pump surgery. Depending on the definition used based on creatine kinase-MB, the incidence of MI after coronary artery bypass grafting (CABG) ranged from 0.6% to 19% and the associated HRs for 30-day mortality ranged from 2.7 to 6.9. Using cardiac troponin (1528 patients), the incidence of MI ranged from 1.7% to 13% depending on the definition used with HRs for 30-day mortality ranging from 5.1 to 7.2. The first cardiac troponin threshold we evaluated, 180xULN, was associated with an adjusted HR for 30-day mortality of 7.6 [95% confidence interval (CI) 3.4-17.1] when compared to <130xULN. The next independent threshold was 130xULN with an adjusted HR for 30-day mortality of 7.8 (95% CI 2.3-26.1). The next cardiac troponin tested threshold (70xULN) did not meet criteria for significance. Our results illustrate that the incidence and prognosis of a post-CABG MI varies based on the definition used. Validated post-CABG MI diagnostic criteria formulated from their independent association with important clinical outcomes are needed.

Myocardial injury after non-cardiac surgery: diagnosis and management.

Myocardial injury after non-cardiac surgery (MINS) is due to myocardial ischaemia (i.e. supply-demand mismatch or thrombus) and is associated with an increased risk of mortality and major vascular complications at 30 days and up to 2 years after non-cardiac surgery. The diagnostic criteria for MINS includes an elevated post-operative troponin measurement judged as resulting from myocardial ischaemia (i.e. no evidence of a non-ischaemic aetiology), during or within 30 days after non-cardiac surgery, and without the requirement of an ischaemic feature (e.g. ischaemic symptom, ischaemic electrocardiography finding). For patients with MINS who are not at high risk of bleeding, physicians should consider initiating dabigatran 110 mg twice daily and low-dose aspirin. Physicians should also consider initiating statin therapy in patients with MINS. Most MINS patients should only be referred to cardiac catheterization if they demonstrate recurrent instability (e.g. cardiac ischaemia, heart failure). Patients ≥65 years of age or with known atherosclerotic disease should have troponin measurements on days 1, 2, and 3 after surgery while the patient is in hospital to avoid missing >90% of MINS and the opportunity to initiate secondary prophylactic measures and follow-up.

Surveillance and Management of Troponin Elevation after Vascular Surgery

Postopertive troponin elevation may occur without typical or atypical cardiac symptoms and is associated with an increased 30-day morbidity and mortality. The objective of the study was to implement a quality improvement initiative of postoperative troponin surveillance algorithm aimed at intensifying medical management after vascular surgery. We conducted a single-center study of postoperative troponin surveillance after vascular surgery (n=201) at a tertiary care, academic medical center from January to December 2016. Troponin surveillance was performed on postoperative days 1-3 after carotid endarterectomy, endovascular aortic repair, infrainguinal bypass, open abdominal aortic aneurysm repair, peripheral vascular intervention, and suprainguinal bypass, regardless of cardiac symptoms. Patients with troponin I elevation (>0.034ng/mL) were managed with a treatment algorithm which included single or dual antiplatelet (AP) agent, high-intensity statin therapy, smoking cessation consultation, and outpatient cardiology consultation and stress testing. Patients with troponin elevation ≥1.0ng/mL received inpatient cardiology consultation. We assessed adherence to the protocol for intensification of best medical therapy defined as high-dose statin therapy, increase in AP therapy, and smoking cessation consultation according to the established algorithm. Troponin elevation was recorded in 17% (34/201) of patients and was associated with cardiac symptoms in 8 patients (24%), while 26 (76%) patients had an asymptomatic abnormal troponin on postoperative surveillance. One patient was excluded due to death immediately after SUPRA, resulting in 200 patients. Troponin elevation ≥1.0ng/mL occurred in 11 asymptomatic patients (5.5%). Any intensification of medical therapy was instituted in 76% of patients with elevated troponin and included high-intensity statin therapy (58%), increase in AP therapy (18%), and smoking cessation consultation (66%). Once an elevated troponin level was recognized, 52% of our patients received cardiology consultation with an increased likelihood (100%) in patients with troponin ≥1ng/mL (P<0.001). Adherence to outpatient stress testing was 66%. Intensification of medical therapy was not significantly different between patients with abnormal troponin values, >0.034-1.0 (n=23) versus ≥1.0ng/mL (n=10); statin therapy (P=1.0), AP (P=0.34), and smoking cessation (P=1.0). One-year mortality was higher in patients with postoperative troponin elevation than those with normal postoperative troponin levels (12% vs. 2.4%; P=0.03). Routine postoperative troponin surveillance results in intensification of statin therapy in patients with asymptomatic troponin elevation. Further study is needed to determine if this approach reduces long-term cardiovascular morbidity and mortality.

Prognostic performance of preoperative cardiac troponin and perioperative changes in cardiac troponin for the prediction of major adverse cardiac events and mortality in noncardiac surgery: A systematic review and meta-analysis.

BackgroundIncreased postoperative cardiac troponin (cTn) independently predicts short-term mortality. Previous studies suggest that preoperative cTn also predicts major adverse cardiovascular events (MACE) and mortality after noncardiac surgery. The value of preoperative and perioperative changes in cTn as a prognostic tool for adverse outcomes has been sparsely investigated.Methods and findingsA systematic review and meta-analysis of the prognostic value of cTns for adverse outcome was conducted. Adverse outcome was defined as short-term (in-hospital or <30 days) and long-term (>30 days) MACE and/or all-cause mortality, in adult patients undergoing noncardiac surgery. The study protocol (CRD42018094773) was registered with an international prospective register of systematic reviews (PROSPERO). Preoperative cTn was a predictor of short- (OR 4.3, 95% CI 2.9–6.5, p<0.001, adjusted OR 5.87, 95% CI 3.24–10.65, p<0.001) and long-term adverse outcome (OR 4.2, 95% CI 1.0–17.3, p = 0.05, adjusted HR 2.0, 95% CI 1.4–3.0, p<0.001). Perioperative change in cTn was a predictor of short-term adverse outcome (OR 10.1, 95% CI 3.2–32.3, p<0.001). It was not possible to conduct pooled analyses for adjusted estimates of perioperative change in cTn as predictor of short- (a single study identified) and long-term (no studies identified) adverse outcome. Further, it was not possible to conduct pooled analyses for unadjusted estimates of perioperative change in cTn as predictor of long-term adverse outcome, since only one study was identified. Bivariate analysis of sensitivities and specificities were performed, and overall prognostic performance was summarized using summary receiver operating characteristic (SROC) curves. The pooled sensitivity and specificity for preoperative cTn and short-term adverse outcome was 0.43 and 0.86 respectively (area under the SROC curve of 0.68). There were insufficient studies to construct SROCs for perioperative changes in cTn and for long-term adverse outcome.ConclusionOur study indicates that although preoperative cTn and perioperative change in cTn might be valuable predictors of MACE and/or all-cause mortality in adult noncardiac surgical patients, its overall prognostic performance remains uncertain. Future large, representative, high-quality studies are needed to establish the potential role of cTns in perioperative cardiac risk stratification.

Pre-Operative Cardiovascular Testing and Post-Renal Transplant Clinical Outcomes.

Cardiovascular disease, a major contributor to morbidity and mortality in chronic kidney disease and kidney transplant patients, is closely evaluated before kidney transplant. We aimed to characterize pre-transplant cardiac testing practices and post-transplant cardiac outcomes at a single academic center. This was a retrospective, single-center analysis of consecutive adults receiving first renal transplant from 1/1/2016 to 6/31/2017. Data included demographics, medical history, and medications. Pre-transplant workup included echocardiograms, cardiac stress testing, coronary computed tomography, left heart catheterization (LHC), and any revascularization. Outcomes included all-cause mortality, cardiac mortality, myocardial infarction (MI), and myocardial injury. Our analysis included 235 patients with mean follow-up of 1.6 ± 0.53 years. Of these, 219 (93%) patients had non-invasive functional testing before transplant, with 198 normal and 21 abnormal. The most common modalities were dobutamine stress echocardiogram (88) and pharmacological myocardial perfusion imaging (60). Twenty-four (10%) patients had an LHC, including 14 abnormal studies, and 10 who subsequently underwent successful revascularization. There were 3 deaths, 2 that were cardiac-specific. There were no ST-elevation MIs and 1 Type I non-ST-elevation MI (NSTEMI), occurring 2 days after transplant. Of those patients with a 30-day post-operative troponin, 30 (13%) patients had an elevation due to a type II NSTEMI or myocardial injury. Non-invasive functional testing is common prior to renal transplantation, with most being normal. Few patients are revascularized before transplantation. Perioperative death and acute coronary syndrome are rare, but troponin elevations due to type II NSTEMI and myocardial injury are common.

A 71-year-old woman with an asymptomatic postoperative troponin elevation.

A 71-year-old woman with an asymptomatic postoperative troponin elevation.

Routine Postoperative Cardiac Testing is Unnecessary after Carotid Endarterectomy

Routine laboratory testing to rule out myocardial infarction (MI) after carotid endarterectomy (CEA) is common in many centers. Its use in this patient population has not been thoroughly investigated. We hypothesize that routine testing for MI in post-CEA patients is of low yield and not cost-effective. A retrospective review of 291 consecutive CEAs from February 2011 to July 2015 was performed. Two patients were excluded: one for postoperative noncardiac death and one for preoperative MI. Patient demographics, medications, medical history, type of anesthesia, and postoperative laboratory results were reviewed. All patients had troponin-I and creatine kinase-MB levels taken postoperatively. A patient was judged to have an MI if troponin-I was greater than or equal to 0.6ng/mL or CK-MB is >6.3ng/mL. The incidence of postoperative MI was recorded, and a cost analysis was performed. The mean age was 70.2 years (range: 42-92). Of all, 59.5% were male, and 92.4% had a history of hypertension. Preoperatively, 57.4% were on beta-blocker therapy, 86.5% on aspirin, and 52.2% on both. Most (80.6%) were on preoperative statin therapy, 26.9% had a prior history of MI (37.2% within 5years of surgery), and 56.4% of patients had a prior coronary intervention (27.6% percutaneous, 28.7% coronary artery bypass grafting, and 11% both). All patients received general anesthesia. The mean procedure time was 121.5min (range: 62-258). The mean postoperative length of stay was 2.6days. Eight patients (2.7%) were judged to have acute MI, one of which was symptomatic. Three of the 8 (38%) had a prior history of MI. In asymptomatic patients, the peak level of troponin-I ranges from 0.52 to 3.64ng/mL and that of CK-MB from 11.8 to 24ng/mL. The symptomatic patient had chest pain and bradycardia. The patient had a peak troponin-I level of 1.59ng/mL, with a CK-MB level of 11.5ng/mL. All patients were treated medically. The cost per troponin-I and CK-MB is $27.78 and $31.44, respectively, in our institution. We estimate that eliminating routine postoperative troponin-I and CK-MB testing in patients who underwent CEA would have saved an estimated $51,343 over the course of treatment of the studied population. Routine postoperative cardiac laboratory testing in asymptomatic patients afterCEA increases the hospital cost. The low overall rate of postoperative MI suggests that cardiac testing is best reserved for symptomatic patients or those with clinical suspicion for MI.

MIDCAB versus off-pump CABG: Comparative study

To investigate the clinical significance of minimally invasive direct coronary artery bypass (MIDCAB). Three hundred patients admitted to the Second Hospital of Shandong University from March 2006 to February 2010 were retrospectively analyzed and received off-pump operation under general anesthesia. Depending on surgical methods, patients were divided into the MIDCAB group (n=90) and the median sternotomy off-pump coronary artery bypass (OPCAB) group, named as the OPCAB group (n=210). Preoperative clinical data, perioperative clinical data, and mid-term follow-up at 7years after operation were analyzed and compared between the two groups. Age and the number of vascular lesions in the OPCAB group were higher than those in the MIDCAB group, whereas left ventricular ejection fraction (LVEF) in the former was lower than that in the latter (p<0.05). The number of distal anastomotic stomas, operation time, blood transfusion volume, postoperative cardiac troponin I (cTnI) peak value, ventilator use time, intensive care unit (ICU) stay, and hospital stay in the MIDCAB group were significantly lower than those in the traditional OPCAB group (p<0.05). Among the 294 recovered cases, 201 cases completed 7years of continuous follow-up, with a follow-up rate of 67.91%. The LVEF and the patency rate of vessels in the MIDCAB group were higher than those in the OPCAB group (p<0.05). Compared with the median sternotomy OPCAB, MIDCAB is characterized by small incision, small trauma, positive efficacy, and safety; therefore, it is worthy of being promoted.

Can human myocardium be remotely preconditioned? The results of a randomized controlled trial.

No experimental study has shown that the myocardium of a remotely preconditioned patient is more resistant to a standardized ischaemic/hypoxic insult. This was a single-centre randomized (1:1), double-blinded, sham-controlled, parallel-group study. Patients referred for elective coronary bypass surgery were allocated to either remote ischaemic preconditioning (3 cycles of 5-min ischaemia/5-min reperfusion of the right arm using a blood pressure cuff inflated to 200 mmHg) or sham intervention. One hundred and thirty-four patients were recruited, of whom 10 dropped out, and 4 were excluded from the per-protocol analysis. The right atrial trabecula harvested on cannulation for cardiopulmonary bypass was subjected to 60 min of simulated ischaemia and 120 min of reoxygenation in an isolated organ experiment. Postoperative troponin T release and haemodynamics were assessed in an in vivo study. The atrial trabeculae obtained from remotely preconditioned patients recovered 41.9% (36.3-48.3) of the initial contraction force, whereas those from non-preconditioned patients recovered 45.9% (39.1-53.7) (P = 0.399). Overall, the content of cleaved poly (ADP ribose) polymerase in the right atrial muscle increased from 9.4% (6.0-13.5) to 19.1% (13.2-23.8) (P < 0.001) after 1 h of ischaemia and 2 h of reperfusion in vitro. The amount of activated Caspase 3 and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells also significantly increased. No difference was observed between the remotely preconditioned and sham-treated myocardium. In the in vivo trial, the area under the curve for postoperative concentration of troponin T over 72 h was 16.4 ng⋅h/ml (95% confidence interval 14.2-18.9) for the remote ischaemic preconditioning and 15.5 ng⋅h/ml (13.4-17.9) for the control group in the intention-to-treat analysis. This translated into an area under the curve ratio of 1.06 (0.86-1.30; P = 0.586). Remote ischaemic preconditioning with 3 cycles of 5-min ischaemia/reperfusion of the upper limb before cardiac surgery does not make human myocardium more resistant to ischaemia/reperfusion injury. NCT01994707.

Postoperative troponin release is associated with major adverse cardiovascular events in the first year after noncardiac surgery

IntroductionTroponin elevations after intermediate-to-high risk noncardiac surgery are common and can predict mortality. However, the prognostic value for early and late major adverse cardiovascular events (MACE) is less well investigated. The authors evaluated the relationship between postoperative troponin release and MACE in the first year after noncardiac surgery. MethodsThis observational cohort registry comprised data of patients aged ≥60 years undergoing intermediate-to-high risk noncardiac surgery between July 2012 and 2015, at the Erasmus University Medical Center, Rotterdam, the Netherlands. High-sensitivity troponin T was measured on day 1 to 3 after surgery. Peak troponin values were divided into four categories: <14 ng·L−1, 14–49 ng·L−1, 50–149 ng·L−1 and ≥150 ng·L−1. The primary endpoint MACE was defined as the occurrence of myocardial infarction, angina, revascularization therapy or cerebrovascular accident in the first year after surgery. The incidence of MACE and all-cause mortality was calculated using Kaplan-Meier estimates. Cox regression was used to estimate risks for both endpoints. ResultsIn total, 3085 patients were included for analyses and peak troponin elevation above 14 ng·L−1 was present in 1678 (54.4%) patients. The overall incidence for one-year MACE was 5.8% (3.4%, 6.1%, 10.4% and 40.6% per increasing troponin category) with adjusted HR (95% CI) 1.32 (0.85–2.06), 2.53 (1.42–4.53) and 10.24 (5.91–17.75) for the consecutive increasing categories. One-year mortality occurred in 14.6% and showed a similar stepwise increase with adjusted HR (95% CI) 1.25 (0.98–1.60), 2.39 (1.72–3.32) and 3.79 (2.60–5.54). ConclusionOur dataset demonstrates a graded relationship between postoperative troponin release and occurrence of MACE in the first year after intermediate-to-high risk noncardiac surgery.

The postoperatıve effects of use of trimetazidine before the coronary artery bypass graft surgery.

In this study, postoperative cardiac functions were observed in patients undergoing coronary artery bypass grafting (CABG) surgery following preoperative administration of the anti-ischemic drug trimetazidine. The study included a total of 50 CABG patients; 25 were administered with trimetazidine preoperatively and 25 did not receive trimetazidine. A retrospective evaluation was made of the parameters of age, gender, preoperative echocardiography (ECHO) results, cross-clamping durations, postoperative inotropic requirements, and postoperative 4th-h troponin-I levels and the groups were compared. There was no statistically significant difference determined between the 2 groups in respect of the data of age, gender, comorbidity, preoperative ECHO signs [(ejection fraction (EF), left ventricle end systolic diameter (lvsd), left ventricle end diastolic diameter (lvdd), left atrium diameter (LA), and intraventricular septum thickness (IVS)], inotropic requirements, and postoperative troponin-I levels. In the control group, a positive correlation was determined between postoperative troponin-I levels and DM (r: 0.597, p: 0.002). There was no correlation determined in the trimetazidine group (r:-0.042, p: 0.844). The results of this study demonstrated a positive correlation between postoperative troponin-I levels and DM in the group not administered with trimetazidine. There was no such correlation determined in the group administered with trimetazidine. This result may suggest that DM may increase troponin-I levels in the absence of trimetazidine, and therefore that the drug may be cardioprotective in such cases. Further studies on more extensive patient populations are required to confirm these results.

EDITORIAL COMMENT

Surgery plays a fundamental role in the care of millions of patients worldwide, each year. 1 Rose J Weiser TG Hider P Wilson L Gruen RL Bickler SW Estimated need for surgery worldwide based on prevalence of diseases: a modelling strategy for the WHO Global Health Estimate. Lancet Global Health. 2015; 3: S13-S20 Abstract Full Text Full Text PDF PubMed Scopus (221) Google Scholar , 2 Sessler DI Devereaux PJ Perioperative troponin screening. Anesth Analg. 2016; 123: 359-360 Crossref PubMed Scopus (34) Google Scholar Unfortunately, cardiovascular events occurring after surgery remain as one of the leading cause of morbidity and mortality after major non-cardiac surgery. The results of several large studies demonstrate that a higher than “normal” postoperative troponin concentrations in the absence of a clinical diagnosis of myocardial infarct (also known as myocardial injury after non-cardiac surgery, MINS) is an independent risk factor of short and long term morbidity and mortality. 3 Association between postoperative troponin levels and 30-Day mortality among patients undergoing noncardiac surgery. JAMA. 2012; 307 Google Scholar , 4 Devereaux PJ Duceppe E Guyatt G et al. Dabigatran in patients with myocardial injury after non-cardiac surgery (MANAGE): an international, randomised, placebo-controlled trial. Lancet. 2018; 391: 2325-2334 Abstract Full Text Full Text PDF PubMed Scopus (163) Google Scholar , 5 Botto F Alonso-Coello P Chan MTV et al. Myocardial injury after noncardiac surgery. Anesthesiology. 2014; 120: 564-578 Crossref PubMed Scopus (597) Google Scholar , 6 Landesberg G Shatz V Akopnik I et al. Association of cardiac troponin, CK-MB, and postoperative myocardial ischemia with long-term survival after major vascular surgery. J Am Coll Cardiol. 2003; 42: 1547-1554 Crossref PubMed Scopus (403) Google Scholar

AUTHOR REPLY

If it were tracked by the CDC, mortality after non-cardiac surgery would rank among the top 4 causes of mortality in the United States. 1 Bartels K Karhausen J Clambey ET Grenz A Eltzschig HK Perioperative organ injury. Anesthesiology. 2013; 119: 1474-1489 Crossref PubMed Google Scholar The aim of our study was to assess the association between postoperative troponin levels, and both short- and intermediate- term mortality in urologic patients undergoing major operations. This baseline information was needed as background information for a quality project to assess the role of routine troponin screening in our department. As such, there are a few inherent biases that were pointed out in this excellent editorial highlighting the role that troponins may play as a biomarker to predict mortality in our surgical patients.

Clinical Relevance of Troponin T Profile Following Cardiac Surgery.

Background: Peak post-operative cardiac troponin T (cTnT) independently predicts mid- and long-term outcome of cardiac surgery patients. A few studies however have reported two peaks of cTnT over the first 48–72 h following myocardial reperfusion. The aim of the current study was to better understand underlying reasons of these different cTnT profiles and their possible relevance in terms of clinical outcome.Methods: All consecutive adult cardiac surgical procedures performed with an extra-corporeal circulation during a >6 years period were retrospectively evaluated. Patients with a myocardial infarction (MI) < 8 days were excluded. cTnT profile of patients with at least one value ≥1 ng/mL value were categorized according to the time occurrence of the peak value. Univariable and multivariable analysis were performed to identify factors influencing early vs. late increase of cTnT values, and to verify the correlation of early vs. late increase with clinical outcome.Results: Data of 5,146 patients were retrieved from our prospectively managed registry. From 953 with at least one cTnT value ≥1 ng/mL, peak occurred ≤ 6 h (n = 22), >6 to ≤ 12 h (n = 366), >12 to ≤ 18 h (n = 176), >18 to ≤ 24 h (171), >24 h (218). Age (OR: 1.023; CI: 1.016–1.030) and isolated CABG (OR: 1.779; CI: 1.114–2.839) were independent predictors of a late increase of cTnT over a limit of 1 ng/ml (p < 0.05), whereas isolated valve procedures (OR: 0.685; CI: 0.471–0.998) and cross-clamp duration (OR: 0.993; CI: 0.990–0.997) independently predicted an early elevation (p < 0.05). Delayed elevation as opposed to early elevation correlated with a higher rate of post-operative complications including MI (19.8 vs. 7.2%), new renal insufficiency (16.3 vs. 6.7%), MACCE (32.0 vs. 15.5%), or death (7.4 vs. 4.4%).Conclusion: Profile of cTnT elevation following cardiac surgery depends on patients' intrinsic factors, type of surgery and duration of cross-clamp time. Delayed increase is of higher clinically relevance than prompt post-operative elevation.

Remote ischaemic preconditioning increases serum extracellular vesicle concentrations with altered micro-RNA signature in CABG patients.

Remote ischaemic preconditioning (RIPC) can attenuate myocardial ischaemia/reperfusion injury but its underlying mechanisms remain largely unknown. Recently, extracellular vesicles (EVs) containing microRNAs (miRNAs) were shown to mediate distant intercellular communication that may be involved in cardioprotection. We tested the hypothesis that RIPC in anaesthetized patients undergoing coronary artery bypass (CABG) surgery results in the release of EVs from the ischaemic/reperfused arm into the blood stream harbouring cardioprotective miRNAs. In 58 patients randomised to RIPC (three 5/5minutes episodes of left arm ischaemia/reperfusion by suprasystolic blood pressure cuff inflations/deflations) or Sham, a subprotocol comprising of parallel right radial artery and regional (left subclavian) venous blood sampling before (awake) and 5 and 60minutes after RIPC/Sham during isoflurane/sufentanil anaesthesia could be completed. EVs were extracted by polymer-based precipitation methods, their concentrations measured, and their miRNA signature analysed. Five minutes after RIPC, regional venous EV concentrations downstream from the cuff increased and arterial concentrations increased after 60minutes (fold change [fc]: RIPC: 1.33±0.5, Sham: 0.91±0.31; P=0.003 for interaction). Already 5minutes after RIPC, expression of 26 miRNAs (threshold fc: 3.0, P<0.05) isolated from EVs including the cardioprotective miR-21 had increased. RIPC also decreased postoperative Troponin I concentrations (AUC RIPC: 336ng/mL×72hours±306 vs Sham: 713±1013; P = 0.041). Remote ischaemic preconditioning increases serum EV concentrations, most likely by early EV release from the patients' left (RIPC) arm, alters their miRNA signature, and is associated with myocardial protection. Thus, an increased EV concentration with an altered miR-signature may mediate the RIPC effect.

Preoperative myocardial troponin T elevation is associated with the fracture type in patients with proximal femoral fracture.

Cardiovascular complications are common in hip fracture patients but the role of fracture type and operative method in these is unclear. This prospective cohort study aimed to evaluate the impact of fracture- and operative characteristics on perioperative cardiovascular complications and prognosis in unselected hip fracture patients. During a 7-month trial registration period, a population of 197 consecutive hip fracture patients (median age 84 years) diagnosed with femoral neck or pertrochanteric fracture was formed. The exclusion criteria were patient refusal, subtrochanteric fracture, or death preoperatively. Pre- and postoperative troponin T (TnT) elevation, perioperative N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) level, perioperative cardiovascular adverse events, and all-cause 30-day and 2- and 5-year mortalities were studied. Femoral neck fracture was independently associated with preoperative myocardial injury witnessed by TnT elevation (HR 2.95, 95% confidence interval 1.21-7.19, p = 0.018). The fracture type, surgery delay, or operative method were not significantly associated with NT-proBNP levels, cardiovascular adverse event diagnoses, or prognosis. Cardiovascular adverse events were clinically diagnosed in 28 (14%) participants, and these had a higher mortality compared to participants without such diagnosis (at 30 days, 32% vs 5%; 2 years, 71% vs 31%; and 5 years, 86% vs 59%; p < 0.001). While the femoral neck fracture independently predicts preoperative cardiovascular morbidity, the operative method does not affect perioperative cardiovascular complications or the prognosis, and it may be selected by the treating clinician based on other criteria.

Mild Perioperative Hypothermia and Myocardial Injury: A Retrospective Cohort Analysis

We tested the primary hypothesis that final intraoperative esophageal temperature is associated with increased odds of a composite of in-hospital all-cause mortality and myocardial injury within 7 days after noncardiac surgery. Secondary exposures were time-weighted average intraoperative temperature and area <37°C threshold. Myocardial injury was defined by postoperative fourth-generation troponin T ≥0.03 ng/mL apparently due to cardiac ischemia. Data were extracted for inpatients who had noncardiac surgery with general anesthesia at the Cleveland Clinic between 2012 and 2015. All had esophageal temperature monitoring and routine postoperative troponin monitoring. We estimated the confounder-adjusted association between final intraoperative esophageal temperature and the collapsed composite with multivariable logistic regression. We similarly estimated associations with time-weighted average intraoperative temperature and area <37°C. Two thousand two hundred ten patients were included. Nearly all final esophageal temperatures were 36°C-37°C. Ninety-seven patients (4.4%) had myocardial injury, and 7 (0.3%) died before discharge. Final intraoperative core temperature was not associated with the collapsed composite: odds ratio, 0.91 (95% confidence interval, 0.68-1.24) per 1°C decrease. Similarly, neither of the secondary exposures was associated with the composite outcome. We did not observe an association between mild perioperative hypothermia and mortality or myocardial injury in adults having noncardiac surgery. However, the range of final intraoperative temperatures was small and largely restricted to the normothermic range (36°C-37°C). Trials are needed to further assess the effect of temperature on myocardial injury.