Diagnosis Of Perioperative Myocardial Infarction Research Articles

How vigilant were we in the diagnosis of peri-operative myocardial infarction before 2022 ESC guidelines?

Abstract Background The diagnosis of myocardial infarction (MI) after non-cardiac surgical intervention is complicated due to possible absence of symptoms as well as of objective ECG or echocardiography signs of ischemia. Aim This is a retrospective analysis of the prevalence of clinically diagnosed MI after non-cardiac surgery in two district hospitals with large-scale surgical services in the period of 2017 - 2022. Methods We retrospectively collected study data using electronic hospital records of all patients that underwent surgical operations for 6 years. Peri-operative MI was selected according to code I21 following any surgical procedure and verified by symptoms, elevated TnI, ECG and Echo changes. Results Total 103 028 patients underwent orthopedic, vascular, abdominal, neuro- surgery from 2017 to 2022. We found 45 patients diagnosed with MI, what makes the prevalence of 0,04%. Diagnostic criteria were: median TnI levels 4925 [1171; 13162] ng/L, symptoms [62% had typical anginal pain, 38% felt dyspnea, 22% had no symptoms], ECG changes {40% with ST elevation, 42% with ST depression, 16% bundle branch block}. Three patients (7%) were administered with troponin test before surgery. Patients with peri-operative MI were 81 [70; 86] years old, 49% females, with the history of CAD (42%), hypertension (71%), diabetes (33%), CKD (13%), anemia (38%), atrial fibrillation (33%), heart failure (47%). The duration of anesthesia was from 20 min to 3h 05 min and it was general in most cases. Bleeding requiring blood transfusion was observed in 27% of cases. It is known that 42% of patients used beta-blockers, 22% used statins before the operation, and 33% saw cardiologist in last 5 years. STEMI occurred in 44%, NSTEMI in 38% of patients, in 18% MI was unspecified, PCI was performed in 44%. Patients were transferred to ICU in 78% of cases and in 20% to cardiology ward. In-hospital deaths occurred in 49% of cases. Conclusions Little number of peri-operative myocardial infarctions are recognized in current practice, however, the mortality of these patients is very high. These findings highlights the importance of implementation of non-cardiac surgery guidelines, namely, routine troponin evaluation in high-risk patients.

Detecting patients with PMI post-CABG based on cardiac troponin-T profiles: A latent class mixed modeling approach

BackgroundDiagnosis of perioperative myocardial infarction (PMI) after coronary artery bypass grafting (CABG) is fraught with complexity since it is primarily based on a single cut-off value for cardiac troponin (cTn) that is exceeded in over 90% of CABG patients, including non-PMI patients. In this study we applied an unsupervised statistical modeling approach to uncover clinically relevant cTn release profiles post-CABG, including PMI, and used this to improve diagnostic accuracy of PMI. MethodsIn 624 patients that underwent CABG, cTnT concentration was serially measured up to 24 h post aortic cross clamping. 2857 cTnT measurements were available to fit latent class linear mixed models (LCMMs). ResultsFour classes were found, described by: normal, high, low and rising cTnT release profiles. With the clinical diagnosis of PMI as golden standard, the rising profile had a diagnostic accuracy of 97%, compared to 83% for an optimally chosen cut-off and 21% for the guideline recommended cut-off value. ConclusionClinically relevant subgroups, including patients with PMI, can be uncovered using serially measured cTnT and a LCMM. The LCMM showed superior diagnostic accuracy of PMI. A rising cTnT profile is potentially a better criterion than a single cut-off value in diagnosing PMI post-CABG.

The association of endothelial injury and systemic inflammation with perioperative myocardial infarction.

Background Major surgery predisposes to endothelial glycocalyx injury. Endothelial glycocalyx injury associates with cardiac morbidity, including spontaneous myocardial infarction. However, the relation between endothelial glycocalyx injury and the development of perioperative myocardial infarction remains unknown. Methods Fifteen perioperative myocardial infarction patients and 60 propensity-matched controls were investigated in this prospective study. The diagnosis of perioperative myocardial infarction was based on repeated cardiac troponin T measurements, electrocardiographs and recordings of ischaemic signs and symptoms. We measured endothelial glycocalyx markers – soluble thrombomodulin, syndecan-1 and vascular adhesion protein 1 – and an inflammatory marker, namely interleukin-6, preoperatively and 6 h and 24 h postoperatively. We calculated the areas under the receiver operating characteristics curves (AUCs) to compare the performances of the different markers in predicting perioperative myocardial infarction. The highest value of each marker was used in the analysis. Results The interleukin-6 concentrations of perioperative myocardial infarction patients were significantly higher preoperatively and 6 and 24 h postoperatively ( P = 0.002, P = 0.002 and P = 0.001, respectively). The AUCs (95% confidence intervals) for the detection of perioperative myocardial infarction were 0.51 (0.34–0.69) for soluble thrombomodulin, 0.63 (0.47–0.79) for syndecan-1, 0.54 (0.37–0.70) for vascular adhesion protein 1 and 0.69 (0.54–0.85) for interleukin-6. Conclusions Systemic inflammation, reflected by interleukin-6, associates with cardiac troponin T release and perioperative myocardial infarction. Circulating interleukin-6 demonstrated some potential to predict perioperative myocardial infarction, whereas endothelial glycocalyx markers did not.

Influence of impairment in renal function on the accuracy of high-sensitivity cardiac troponin T for the diagnosis of perioperative myocardial infarction after heart valve surgery.

We aimed to assess the influence of impairment in renal function over the high-sensitivity cardiac troponin T (hs-cTnT) accuracy to diagnose perioperative myocardial infarction (MI) after heart valve surgery. Heart valve surgery was performed in 805 patients from June 2012 to January 2016. Patients with enzymatic curves of hs-cTnT suggestive of myocardial necrosis and electrocardiogram and/or transthoracic echocardiogram criteria were identified as patients with perioperative MI. Impairment in renal function was defined as a postoperative creatinine clearance <50 ml/min at 16 h after surgery and for at least 48 h. Patients included were divided into 2 groups at 16 h: (i) patients with normal renal function (creatinine clearance >50 ml/min) and (ii) patients with impairment in renal function (creatinine clearance <50 ml/min). From a total of 805 patients undergoing heart valve surgery, 88 patients developed perioperative MI. When comparing receiver operating characteristic curves in patients with perioperative MI according to renal function, the optimal threshold of hs-cTnT at 16 h differed in patients with impairment in renal function (1303 vs 1095 pg/ml, P < 0.001). The diagnostic accuracy of hs-cTnT at 16 h was 93.4% [95% confidence interval (CI) 89.98-96.86], with an area under receiver operating characteristic curve (0.993, 95% CI 0.988-0.999 vs 0.972, 95% CI 0.952-0.992; P < 0.001). Renal function might influence in hs-cTnT levels. However, a hs-cTnT threshold of 1303 pg/ml at 16 h may be applied according to renal function to diagnose perioperative MI after cardiac surgery.

Positivity threshold value for cardiac troponin lc in the diagnosis of perioperative myocardial infarction after on-pump cardiac surgery in adult patients

IntroductionL'objectif de cette étude prospective, réalisée sur une année au laboratoire de biochimie de l'HMIMV de Rabat, vise à étudier la cinétique de la Troponine Ic (TnIc) après chirurgie cardiaque sous circulation extracorporelle (CEC) en vue d'établir des valeurs seuils pour le diagnostic d'infarctus de myocarde péri-opératoire (IDMPO).MéthodesNous avons inclus 58 patients opérés pour chirurgie valvulaire ou pontage coronarien sous CEC. Ces patients ont été séparés en 3 groupes selon l'évolution clinique, biologique (TnIc) et électrique durant la période post opératoire précoce. Nous avons dosé et suivi la cinétique de la TnIc par une technique immuno-enzymatique, au moyen du réactif FlexR CTNI avant et après la CEC, à H0, H3, H6, H12, H21, H24 et H72 sur l'automate Dimension Xpand plusR de la société Siemens.RésultatsLes résultats obtenus sont plus élevés qu'en cardiologie, même chez le groupe des patients sans complications cardiaques post opératoires, avec un taux moyen de TnIc environ 2,5 fois supérieur à la valeur seuil en cardiologie. La cinétique de libération est significativement différente entre les 3 groupes (p‹0,05).ConclusionLa valeur seuil que nous proposons pour confirmer le diagnostic de l'IDMPO est de 13ng/ml obtenue entre H12 et H24. Nous recommandons, de ce fait, un à deux prélèvements vers H12 puis entre H20 et H24.

Diagnosis of perioperative myocardial infarction after heart valve surgery with new cut-off point of high-sensitivity troponin T and new electrocardiogram or echocardiogram changes

ObjectiveCriteria for diagnosing myocardial infarction (MI) after heart valve surgery are not collected in the Third Universal Definition of MI. We aimed to define cut-offs for high-sensitivity cardiac troponin T (hs-cTnT) and creatine kinase-MB (CK-MB) for the diagnosis of perioperative MI after heart valve surgery according to perioperative MI determined by new alterations in electrocardiogram (ECG) and/or transthoracic echocardiogram (TTE). Secondary endpoints were incidence of perioperative MI, postoperative complications, 30-day mortality, and 2-year survival. MethodsHeart valve surgery was performed in 805 patients (June 2012-January 2016). hs-cTnT and CK-MB were measured at intensive care unit (ICU) admission and 8, 16, 24, 48, and 72 hours after surgery. Blind to outcomes, we analyzed ECGs and TTEs before and after surgery. Patients were divided into 2 groups: with ECG and/or TTE criteria after surgery (following the consensus statement) and without these changes. We conducted receiver operating characteristic analyses for hs-cTnT and CK-MB in the group with ECG and/or TTE criteria. ResultsECG and/or TTE criteria were observed in 88 patients. Receiver operating characteristic analyses in this group showed hs-cTnT levels of 732.3 pg/mL at ICU admission; 1008 pg/mL at 8 hours, 1057 pg/mL at 16 hours, and 958.3 pg/mL at 24 hours after surgery (P < .001) and CK-MB levels of 26.78 mg/dL at ICU admission, 54.88 mg/dL at 8 hours, 38.98 mg/dL at 16 hours, and 18.4 mg/dL at 24 hours after surgery (P < .001). ConclusionsCut-offs for hs-cTnT and CK-MB to diagnose perioperative MI after heart valve surgery are well above upper reference limit. These findings update the Third Universal Definition providing cut-offs to diagnose perioperative MI after heart valve surgery.

Heart-Type Fatty Acid Binding Protein and Ischemia-Modified Albumin for Detection of Myocardial Infarction After Coronary Artery Bypass Graft Surgery

Heart-type fatty acid binding protein (hFABP) and ischemia-modified albumin (IMA) have been put forward as novel biomarkers to detect myocardial injury shortly after onset of ischemia. We compared hFABP and IMA with cardiac troponin I (cTnI) for speed and reliability in the diagnosis of perioperative myocardial infarction (PMI) after coronary artery bypass graft surgery (CABG). In all, 210 consecutive patients undergoing isolated CABG with cardiopulmonary bypass were enrolled in a prospective study. Blood samples were taken perioperatively and throughout the first 72 hours after surgery; clinical data and events were recorded. In cohort A, serum concentrations of hFABP and cTnI were measured using a combined quantitative bedside assay. In cohort B, IMA and cTnI serum concentrations were measured using an albumin cobalt binding test. Perioperative myocardial infarction was defined using a cTnI cutoff of greater than 10.5 ng/mL occurring within 24 hours of CABG or new electrocardiographic changes. In cohort A, 14 patients were identified with PMI (group 1), whereas 94 had no PMI and served as controls (group 2). Both hFABP and cTnI were increased in group 1 as compared with group 2 (p < 0.001). Although cTnI did not differ before 12 hours, hFABP diverged much earlier, at 1 hour postoperatively (p < 0.001). An hFABP concentration of 20 μg/mL at 1 hour detected PMI with an area under the curve of 77.1%. In cohort B, 18 patients were identified with PMI (group 3), and 84 patients served as controls (group 4). No difference in cTnI values could be observed between the groups until 12 hours postoperatively. Ischemia-modified albumin failed to differentiate at any postoperative time point; the low discriminative power of IMA was confirmed with an area under the curve of 53.3% at 1 hour, 48.5% at 6 hours, and 39.3% at 12 hours postoperatively. Heart-type fatty acid binding protein is a sensitive and rapid biomarker that detected PMI reliably at 1 hour after CABG, much earlier than cTnI. The diagnostic value of IMA for detection of PMI appears to be very limited in this setting.

Kinetics of high sensitive troponin T (HSTNT) after cardiac surgery

Perioperative myocardial infarction (PMI) in the setting of cardiac surgery represent a considerable risk to patients with significant mortality and morbidity. The role of highly sensitive cardiac troponin T (hsTnT) has not been evaluated in the setting of cardiac surgery, instead Cardiac Troponin T (TnT) and Creatine Kinase MB (CK-MB) are commonly used for the diagnosis of PMI [1].

Predictors of Mortality and Prolonged Hospital Stay after Diagnosis of Perioperative Myocardial Infarction in Patients Undergoing Isolated Coronary Artery Bypass Crafting

Objective: To determine predictors of mortality and prolonged hospital stay in patients presenting perioperative myocardial infarction (PMI) after CABG.

Kinetics of Highly Sensitive Troponin T after Cardiac Surgery

Perioperative myocardial infarction (PMI) confers a considerable risk in cardiac surgery settings; finding the ideal biomarker seems to be an ideal goal. Our aim was to assess the diagnostic accuracy of highly sensitive troponin T (hsTnT) in cardiac surgery settings and to define a diagnostic level for PMI diagnosis. This was a single-center prospective observational study analyzing data from all patients who underwent cardiac surgeries. The primary outcome was the diagnosis of PMI through a specific level. The secondary outcome measures were the lengths of mechanical ventilation (LOV), stay in the intensive care unit (LOSICU), and hospitalization. Based on the third universal definition of PMI, patients were divided into two groups: no PMI (Group I) and PMI (Group II). Data from 413 patients were analyzed. Nine patients fulfilled the diagnostic criteria of PMI, while 41 patients were identified with a 5-fold increase in their CK-MB (≥120 U/L). Using ROC analysis, a hsTnT level of 3,466 ng/L or above showed 90% sensitivity and 90% specificity for the diagnosis of PMI. Secondary outcome measures in patients with PMI were significantly prolonged. In conclusion, the hsTnT levels detected here paralleled those of CK-MB and a cut-off level of 3466 ng/L could be diagnostic of PMI.

Plasma levels of microRNA-499 provide an early indication of perioperative myocardial infarction in coronary artery bypass graft patients.

BackgroundRecent studies indicated that microRNAs (miRNAs, miRs) were important for many biological and pathological processes, and they might be potential biomarkers for cardiovascular diseases. The present study aims to determine the release patterns of miRNAs in cardiac surgery and to analyze the ability of miRs to provide early prediction of perioperative myocardial infarction (PMI) in patients undergoing coronary artery bypass graft (CABG) surgery.Methodology/Principal FindingsThirty on-pump CABG patients were recruited in this study; and miR-499, miR-133a and miR-133b, cardiac troponin I (cTnI) were selected for measurement. Serial plasma samples were collected at seven perioperative time points (preoperatively, and 1, 3, 6, 12, 24, and 48 hours after declamping) and were tested for cTnI and miRs levels. Importantly, miR levels peaked as early as 1–3 hours, whereas cTnI levels peaked at 6 hours after declamping. Peak plasma concentrations of miRs correlated significantly with cTnI (miR-499, r = 0.583, P = 0.001; miR-133a, r = 0.514, P = 0.006; miR-133b, r = 0.437, P = 0.05), indicating the degree of myocardial damage. In addition, 30 off-pump CABG patients were recruited; miR-499 and miR-133a levels were tested, which were significantly lower in off-pump group than in on-pump group. A prospective cohort of CABG patients (n = 120) was recruited to study the predictive power of miRs for PMI. The diagnosis of PMI strictly adhered to the principles of universal definition of myocardial infarction. The data analysis revealed that miR-499 had higher sensitivity and specificity than cTnI, and indicated that miR-499 could be an independent risk factor for PMI.ConclusionOur results demonstrate that circulating miR-499 is a novel, early biomarker for identifying perioperative myocardial infarction in cardiac surgery.

Perioperative myocardial infarction in patients undergoing myocardial revascularization surgery.

IntroductionPerioperative myocardial infarction adversely affects the prognosis of patients undergoing coronary artery bypass graft and its diagnosis was hampered by numerous difficulties, because the pathophysiology is different from the traditional instability atherosclerotic and the clinical difficulty to be characterized.ObjectiveTo identify the frequency of perioperative myocardial infarction and its outcome in patients undergoing coronary artery bypass graft.MethodsRetrospective cohort study performed in a tertiary hospital specialized in cardiology, from May 01, 2011 to April 30, 2012, which included all records containing coronary artery bypass graft records. To confirm the diagnosis of perioperative myocardial infarction criteria, the Third Universal Definition of Myocardial Infarction was used.ResultsWe analyzed 116 cases. Perioperative myocardial infarction was diagnosed in 28 patients (24.1%). Number of grafts and use and cardiopulmonary bypass time were associated with this diagnosis and the mean age was significantly higher in this group. The diagnostic criteria elevated troponin I, which was positive in 99.1% of cases regardless of diagnosis of perioperative myocardial infarction. No significant difference was found between length of hospital stay and intensive care unit in patients with and without this complication, however patients with perioperative myocardial infarction progressed with worse left ventricular function and more death cases.ConclusionThe frequency of perioperative myocardial infarction found in this study was considered high and as a consequence the same observed average higher troponin I, more cases of worsening left ventricular function and death.

Abstract 9965: Prediction and Diagnosis of Perioperative Myocardial Infarction with High-sensitivity troponin T

Introduction The role of high-sensitivity troponin assays in the prediction and diagnosis of perioperative myocardial infarction is unknown. Methods This is an ancillary study of the Vitamins in Nitrous Oxide (VINO) Trial where 625 patients with or at risk for coronary artery disease undergoing major noncardiac surgery were studied..Plasma hsTnT (Roche) and standard troponin I (Siemens) were measured serially and 12-lead ECGs were obtained. Results At baseline 75% of patients (455/606) had a measurable preoperative hsTNT and 25% had a hsTnT &lt;3 pg/mL. The median hsTnT was 7.4 pg/mL (IQR 2.3 - 15.2). Postoperatively, 409/568 patients (72%) had an increase in hsTnT (median 2.9 pg/mL; IQR 0 - 7.4) and 159/569 (28%) had no change. The median peak hsTnT was 12.2 pg/mL (IQR 6.1 - 23.0). Peak and delta hsTnT and troponin I measurements were tightly correlated (r= 0.99 and 0.99, respectively). Eighty-two patients (13%) had a clinically relevant postoperative TnI elevation &gt;0.07 ng/mL and 30/605 (5%) had a myocardial infarction. Using the median preoperative hsTnT concentration of 7.4 pg/mL, patients above this level had a nearly 3-fold risk to develop a clinically significant postoperative troponin elevation (odds ratio 2.80, 95% CI: 1.69 - 4.63, p&lt; 0.001) and to develop postoperative myocardial infarction (odds ratio 2.94, 95% CI 1.29 - 6.71, p= 0.007). At 7.4 pg/mL, the sensitivity and specificity for postoperative troponin elevation were 71% and 54% and for postoperative myocardial infarction 73% and 52% (Figure 1). Conclusions: Preoperative hsTNT concentrations can be detected in most adult patients with or at risk for coronary artery disease before surgery and may be useful in preoperative risk-stratification for postoperative myocardial infarction. Postoperative increase in hsTnT (delta hsTnT) is common among patients with cardiovascular risk factors and may be useful as objective quantification of perioperative myocardial injury.

Invited Commentary

Perioperative myocardial infarction (PMI) is an important determinant of mortality after coronary artery bypass grafting (CABG). By universal definitions, PMI is defined by an elevation of serum biomarker value more than fivefold the 99th percentile of the normal reference range in the first 72 hours following CABG along with electrocardiograph changes or angiographic evidence of native vessel or graft occlusion [1Thygesen K. Alpert J.S. White H.D. et al.Universal definition of myocardial infarction.Circulation. 2007; 116: 2634-2653Crossref PubMed Scopus (2110) Google Scholar]. Diagnostic criteria of PMI remain controversial in reported studies; the answer to which serum biomarker is most predictive of death after CABG, and the magnitude of rise of such a marker in blood, is a matter of debate. In this issue of The Annals of Thoracic Surgery, Dr van Boxtel and associates attempt to answer whether a noncardiac specific serum biomarker, aspartate aminotransferase (AST), can be regarded as a predictor of perioperative and late mortality in a retrospective study of 13,505 patients that have undergone isolated CABG in a single centre from January 1998 to December 2010 [2van Boxtel A.G.M. Bramer S. Hamad M.A.S. van Straten A.H.M. Perioperative serum aspartate aminotransferase level as a predictor of survival after coronary artery bypass grafting.Ann Thorac Surg. 2012; 94: 1492-1499Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar]. They arbitrarily divided postoperative AST levels into five incremental groups and obtained greater than 91% follow-up at a mean of 5.9 years. Their main findings were that AST was an independent predictor of all-cause early and late mortality, with a graded increase in the odds ratio of mortality amongst the five AST groups (unadjusted and adjusted). For late mortality, AST > 300 resulted in an adjusted hazard ratio (HR) equivalent to the HR of having severe preoperative left ventricular dysfunction (HR = 2.5). Furthermore, incremental increases in AST were associated with higher rates of PMI. The clinical significance in elevation of serum biomarkers after CABG is reflected by important publications in this topic over the past 40 years. Much focus has been on cardiac-specific biomarkers such as creatinine kinase myocardial band (CK-MB) and troponin. A recent metaanalysis (one of the largest to date) of 18,908 CABG patients showed a strong, graded independent association between elevation of CK-MB or troponin within the first 24 hours and early and intermediate mortality after CABG [3Domanski M.J. Mahaffey K. Hasselblad V. et al.Association of myocardial enzyme elevation and survival following coronary artery bypass graft surgery.JAMA. 2011; 305: 585-591Crossref PubMed Scopus (202) Google Scholar]. The metaanalysis showed that mortality rate doubles at a CK-MB ratio of 4.4. Another large metaanalysis of 29,483 patients showed that CK-MB release of fivefold to eightfold the upper limit of normal was associated with an increase risk of death for the next 40 months after CABG [4Petaja L. Salmenpera M. Pulkki K. et al.Biochemical injury markers and mortality after coronary artery bypass grafting: a systematic review.Ann Thorac Surg. 2009; 87: 1981-1992Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar]. These studies highlight the fact that such enzyme elevation perioperatively is prognostically important for early and longer-term mortality. Elevation in these biomarkers after CABG can occur in the absence of graft occlusion; such elevations may be due to regional or global myocardial ischemia from a variety of causes or from direct myocardial injury. Regardless of the cause, myocardial necrosis depicted by cardiac-specific enzymes is associated with worse prognosis. In this milieu, Dr van Boxtel and his team's investigation with serum AST, which is a noncardiac specific biomarker, speaks to the fact that a rise in AST, regardless of the presence of myocardial necrosis or infarction, is associated with worse outcomes after CABG. This study does not, however, answer two highly relevant questions, namely the comparative value of AST or the added value of AST in conjunction with other cardiac-specific biomarkers. Nonetheless, the authors should be congratulated for their rigorous work in bringing the spotlight back on this important yet understudied marker in cardiac surgery. Perioperative Serum Aspartate Aminotransferase Level as a Predictor of Survival After Coronary Artery Bypass GraftingThe Annals of Thoracic SurgeryVol. 94Issue 5PreviewElevated cardiac enzymes after coronary artery bypass grafting (CABG) surgery have been identified as a risk factor for worse postoperative outcome. Cardiac enzymes play an important role in the diagnosis of perioperative myocardial infarction. This study aims to investigate the predictive value of aspartate aminotransferase (AST) with respect to early and late mortality after CABG. Full-Text PDF

Journal-related Activities and Other Special Activities at the 2012 American Society of Anesthesiologists Annual Meeting

Journal-related Activities and Other Special Activities at the 2012 American Society of Anesthesiologists Annual Meeting

Clinical presentation and outcome of perioperative myocardial infarction in the very elderly following hip fracture surgery

Patterns of clinical symptoms and outcomes of perioperative myocardial infarction (PMI) in elderly patients after hip fracture repair surgery are not well defined. A retrospective 1:2 case-control study in a cohort of 1212 elderly patients undergoing hip fracture surgery from 1988 to 2002 in Olmsted County, Minnesota. The mean age was 85.3 ± 7.4 years; 76% female. PMI occurred in 167 (13.8%) patients within 7 days, of which 153 (92%) occurred in first 48 hours; 75% of patients were asymptomatic. Among patients with PMI, in-hospital mortality was 14.4%, 30-day mortality was 29 (17.4%), and 1-year mortality was 66 (39.5%). PMI was associated with a higher inpatient mortality rate (odds ratio [OR], 15.1; confidence interval [CI], 4.6-48.8), 30-day mortality (hazard ratio [HR], 4.3; CI, 2.1-8.9), and 1-year mortality (HR, 1.9; CI, 1.4-2.7). Elderly patients, after hip fracture surgery, have a higher incidence of PMI and mortality than what guidelines indicate. The majority of elderly patients with PMI did not experience ischemic symptoms and required cardiac biomarkers for diagnosis. The results of our study support the measurement of troponin in postoperative elderly patients for the diagnosis of PMI, in order to implement in-hospital preventive strategies to reduce PMI-associated mortality.

Perioperative Serum Aspartate Aminotransferase Level as a Predictor of Survival After Coronary Artery Bypass Grafting

Elevated cardiac enzymes after coronary artery bypass grafting (CABG) surgery have been identified as a risk factor for worse postoperative outcome. Cardiac enzymes play an important role in the diagnosis of perioperative myocardial infarction. This study aims to investigate the predictive value of aspartate aminotransferase (AST) with respect to early and late mortality after CABG. Patients undergoing isolated CABG in a single center between January 1998 and December 2010 were prospectively enrolled in our database. Patients were arbitrarily divided into 4 groups according to the postoperative AST level: group 1 (AST < 50 U/L), group 2 (AST = 51 to 100 U/L), group 3 (AST = 101 to 200 U/L), group 4 (AST = 201 to 300 U/L), and group 5 (AST > 300 U/L). The impact of biomedical variables on early mortality was determined using univariate and multivariate logistic regression analyses. Risk factors for late mortality were identified using Cox proportional hazard regression analyses. The study population consisted of 13,505 patients who underwent isolated CABG. Postoperative AST level was identified as a risk factor for early (odds ratio = 3.6 [2.5 to 5.4], p < 0.0001) and late mortality (hazard ratio = 1.4 [1.2 to 1.7], p < 0.001). After correction for other risk factors, AST level was an independent predictor of worse survival. Elevated postoperative AST level is an independent predictor of early and late mortality after CABG. Although it is not a specific indicator for cardiac damage, it can reflect ischemic effects on the other organs as an indirect sign of depressed cardiac function.

Invited Commentary

Myocardial infarction (MI) occurring in the context of cardiac surgery is a complication difficult to define and to diagnose. The edge between innocuous ischemia induced by cardioplegic arrest and clinically relevant myocardial cell damage is often vague. Most surgeons will indulge with elevated postoperative cardiac troponin I (cTnI) or CK-MB release finding it difficult to associate this finding with a relevant clinical outcome. In many postoperative intensive care units, these biomarkers are not even measured. The study by Lim and colleagues [1Lim C.C.S. Cuculi F. van Gaal W.J. et al.Early diagnosis of perioperative myocardial infarction after coronary bypass grafting: a study using biomarkers and cardiac magnetic resonance imaging.Ann Thorac Surg. 2011; 92: 2046-2053Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar] provides useful information: they demonstrate that even limited cTnI postoperative release is associated with myocardial cell necrosis detected by cardiac magnetic resonance late gadolinium enhancement (CMR-LGE). They confirm cTnI as being, so far, the best predictor of significant myocardial damage after cardiac operations. Previous studies have demonstrated a clear and independent association between cTnI postoperative release and clinical outcome. Knowing this, surgery should be aimed to limit cTnI release at the smaller amount possible: most often operations are performed on patients with severely compromised heart function and further deterioration of the ventricular function can be associated with poor short-term and long-term outcome. Unfortunately, the article by Lim and colleagues does not help us to understand the cause of perioperative myocardial damage: is it caused by poor myocardial protection, early graft closure, incomplete revascularization, surgical manipulation, or iatrogenic coronary damage? This information would be essential to adopt adequate management. The authors suggest that early angiography or surgical inspection should be considered when cTnI is elevated early postoperatively given that cTnI >7.5 ng/mL 1 hour after the end of the operation has a 95% specificity to detect new MI with CMR-LGE. Is it enough information to bring a patient back to the operating room or to the catheter-laboratory? Probably not. An excellent clinical judgment is required to portray laboratory findings. An early postoperative cTnI peak measured 2–3 hours after the operation followed by a rapid decrease is probably the effect of imperfect myocardial protection: in this situation, a chest re-opening or angiography would only be harmful. On the other hand, a progressive cTnI increase with an elevated peak value observed 36–48 hours after the operation, associated or not with ECG abnormalities and hemodynamic instability, is probably caused by an ongoing ischemic trigger (graft closure, incomplete revascularization, or coronary damage): in this case, an aggressive management would probably lead to the recognition of the ischemic trigger and to an adequate treatment. Another interesting finding of the study is that patients with postoperative LGE had an increased systemic inflammatory reaction measured by interleukin 6 (IL-6) and TNFa. Future studies will be needed to clarify the reason of this finding: is it myocardial ischemia causing enhanced inflammatory reaction or is it excessive systemic inflammatory response leading to myocardial cell damage? Early Diagnosis of Perioperative Myocardial Infarction After Coronary Bypass Grafting: A Study Using Biomarkers and Cardiac Magnetic Resonance ImagingThe Annals of Thoracic SurgeryVol. 92Issue 6PreviewMyocardial injury related to coronary artery bypass grafting (CABG) is poorly characterized, and understanding the characteristic release of biomarkers associated with revascularization injury might provide novel therapeutic opportunities. This study characterized early changes in biomarkers after revascularization injury during on-pump CABG. Full-Text PDF

Early Diagnosis of Perioperative Myocardial Infarction After Coronary Bypass Grafting: A Study Using Biomarkers and Cardiac Magnetic Resonance Imaging

Myocardial injury related to coronary artery bypass grafting (CABG) is poorly characterized, and understanding the characteristic release of biomarkers associated with revascularization injury might provide novel therapeutic opportunities. This study characterized early changes in biomarkers after revascularization injury during on-pump CABG. This prospective study comprised 28 patients undergoing on-pump CABG and late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMRI) who underwent measurements of cardiac troponin I (cTnI), creatine kinase-MB, and inflammatory markers (C-reactive protein, serum amyloid A, myeloperoxidase, interleukin 6, tumor necrosis factor-α, matrix metalloproteinase 9a, monocyte chemotactic protein-1, plasminogen activator inhibitor-1a) at baseline, at 1, 6, 12, and 24 hours, and at 1 week (inflammatory markers only) post-CABG. Biomarker results at 1 hour were studied for a relationship to new myocardial infarction as defined by CMRI-LGE, and the diagnostic utility of combining positive biomarkers was assessed. All patients had an uneventful recovery, but 9 showed a new myocardial infarction demonstrated by new areas of hyperenhancement on CMR. Peak cTnI at 24 hours (ρ = 0.66, p < 0.001) and CK-MB (ρ = 0.66, p < 0.001) correlated with the amount of new LGE. At 1 hour, 3 biomarkers--cTnI, interleukin 6, and tumor necrosis factor-α--were significantly elevated in patients with vs those without new LGE. Receiver operating curve analysis showed cTnI was the most accurate at detecting new LGE at 1 hour: a cutoff of cTnI exceeding 5 μg/L at 1 hour had 67% sensitivity and 79% specificity for detecting new LGE. Unexpected CABG-related myocardial injury occurs in a significant proportion of patients. A cTnI test at 1 hour after CABG could potentially differentiate patients with significant revascularization injury.

From Creatine Kinase-MB to Troponin

From Creatine Kinase-MB to Troponin