Peri-operative troponin I concentration as a marker of long-term postoperative adverse cardiac outcomes ? A study in high-risk surgical patients

Postoperative elevated cardiac troponin levels predict all-cause mortality and major adverse cardiovascular events following noncardiac surgery: A dose-response meta-analysis of prospective studies

STUDY OBJECTIVE

To perform a dose-response meta-analysis for the association between postoperative myocardial injury (PMI) in noncardiac surgery and the risk of all-cause mortality or major adverse cardiovascular event (MACE).

DESIGN

Dose-response meta-analysis of prospective studies with weighted (WL) or generalized (GL) linear and restricted cubic spline (RCS) regression.

SETTING

Teaching hospitals.

PATIENTS

Adult patients undergoing noncardiac surgery.

INTERVENTIONS

No.

MEASUREMENTS

The primary outcome was all-cause mortality. The secondary outcome was MACE.

MAIN RESULTS

29 studies (53,518 patients) were included. The overall incidence of PMI was 26.0% (95% CI 21.0% to 32.0%). Compared to those without PMI, patients with PMI had an increased risk of all-cause mortality at short- (<12 months) (cardiac troponin[cTn]I: unadj OR 1.71,95%CI 1.22 to 2.41, P < 0.001; cTnT: unadj OR 2.33,95%CI 2.07 to 2.63, P < 0.001), and long-term (≥ 12 months) (cTnI: unadj OR 1.80, 95%CI 1.63 to 1.99; cTnT: unadj OR 1.47,95%CI 1.33 to 1.62) (All P < 0.001) follow-up. For MACE, the group with elevated values was associated with an increased risk (cTnI: unadj OR 1.98, 95% CI 1.13 to 3.47, P = 0.018; cTnT: unadj OR 2.29, 95% CI 1.88 to 2.79, P < 0.001). Dose-response analysis showed positive associations between PMI (per 1× upper reference limit[URL] increment) and all-cause mortality both at short- (unadj OR) (WL, OR 1.09, 95% CI 1.09 to 1.10; GL, OR 1.06, 95% CI 1.06 to 1.07; RCS in the range of 1-2× URL, OR = 2.43, 95%CI 2.25 to 2.62) and long-term follow-up (unadj HR) (WL, OR 1.16, 95% CI 1.14 to 1.17; GL, OR 1.15, 95% CI 1.13 to 1.16; RCS in the range of 1-2.75× URL, OR = 1.23, 95%CI 1.13 to 1.33), and MACE at longest follow-up (unadj OR) (WL: OR 1.53, 95% CI 1.49 to 1.57; GL: OR 1.46, 95% CI 1.42 to 1.50; RCS in the range of 1-2 x URL, OR = 3.10, 95%CI 2.51 to 3.81) (All P < 0.001). For mild cTn increase below URL, the risk of mortality increased with every increment of 0.25xURL (WL, OR 1.03, 95% CI 1.02 to 1.03; GL, OR 1.05, 95% CI 1.03 to 1.07; RCS in the range of 0-0.5 URL, OR = 9.41, 95% CI 7.41 to 11.95) (All P < 0.001).

CONCLUSIONS

This study shows positive WL or GL and RCS dose-response relationships between PMI and all-cause mortality at short (< 12 mons)- and long-term (≥ 12 mons) follow-up, and MACE at longest follow-up. For mild cTn increase below URL, the risk of mortality also increases even with every increment of 0.25× URL.

Predictive Model of Cerebral Vasospasm in Subarachnoid Hemorrhage Based on Regression Equation

In order to explore the regression equation for the prediction model of subarachnoid hemorrhage and cerebral vasospasm, the nomogram prediction model of SCVS occurrence was established. This study is a retrospective analysis of 125 cases of aSAH admitted to a hospital; the patients were divided into SCVS group and non-SCVS group. Select SIRI as a simple and reliable marker of inflammation, analyze its correlation with SCVS and its predictive value, and analyze the predictive value of SIRI to SCVS through ROC curve. Based on the SIRI inflammation level and other related risk factors, a nomogram prediction model for the occurrence of SCVS was built. The experimental results show that the SIRI level of patients in the SCVS group was significantly higher than that of the non-SCVS group, and logistic regression analysis found that SIRI is an independent risk factor for SCVS. SIRI = 3.63 × 10⁹/L is the best cutoff value for diagnosing the occurrence of SCVS. When TC = 2.24 mmol/L and SIRI = 3.63 × 10%/L, its Youden Index is the largest (0.312, 0.296) and is the best cutoff value for predicting the occurrence of SCVS; at the same time, its prediction accuracy (area under the ROC curve (AUC)), sensitivity, specificity, the positive predictive value, and negative predictive value are 0.743, 72.70%, 80.10%, 77.53%, and 94.24% and 0.725, 70.60%, 76.90%, 73.49%, and 93.59%. Nomogram prediction model establishment and evaluation combined with the results of multifactor analysis are used to build an individual nomogram prediction model. The model has good prediction consistency (C-index = 0.685, P < 0.01). ROC analysis results showed that the model that combined SIRI and other standard variables (AUC = 0.896, 95% CI was 0.803-0.929, P < 0.001) was better than the model that did not combine SIRI (AUC = 0.859, 95% CI was 0.759-0.912, P < 0.001) and the model based only on SIRI (AUC = 0.725, 95% CI was 0.586-0.793, P = 0.001) has better predictive value for SCVS. Joint SIRI will optimize the prediction performance of the nomogram model and improve the early recognition and screening capabilities of SCVS.

Prognostic Value of Cardiac Troponin I and T on Admission in Mortality of Multiple Trauma Patients Admitted to the Emergency Department: a Prospective Follow-up Study

Introduction:

The relationship between increased levels of cardiac troponins and morbidity and mortality of traumatic patients is not still well recognized.

Aim:

The aim of this study was to investigate the prognostic value of cardiac troponin I and T on admission in mortality of multiple trauma patients admitted to the emergency department.

Methods:

In this prospective follow-up study, the cardiac troponin I and T levels were measured in patients with multiple trauma referring to the emergency department (ED) between March 2014 and February 2015 at Imam Khomeini Hospital, Sari, Iran. Patients were followed prospectively until discharge from hospital or death.

Results:

The levels of cardiac troponins I and T in patients with multiple trauma were significantly associated with their mortality, especially at the level of 0.5 and 1.2 μg/dl (p<0.05). Multivariate regression analysis showed association of level of cardiac troponin I and T with patients’ mortality, after controlling for patients’ age, vital signs and GCS on admission. The sensitivity and specificity of troponin I at levels greater than 0.4 μg/dl in predict mortality in this study were as 65.5% and 55.3%, while the values for troponin T were 65.1% and 54.9%, respectively.

Conclusion:

Elevated cardiac troponin I and T levels provide excellent prognostic information regarding mortality in patients with multiple-trauma, independent of age, hemodynamic variables and GCS score.

One-Year Mortality, Causes of Death, and Cardiac Interventions in Patients with Postoperative Myocardial Injury

BACKGROUND

To evaluate the role of routine troponin surveillance in patients undergoing major noncardiac surgery, unblinded screening with cardiac consultation per protocol was implemented at a tertiary care center. In this study, we evaluated 1-year mortality, causes of death, and consequences of cardiac consultation of this protocol.

METHODS

This observational cohort included 3224 patients ≥60 years old undergoing major noncardiac surgery. Troponin I was measured routinely on the first 3 postoperative days. Myocardial injury was defined as troponin I >0.06 μg/L. Regression analysis was used to determine the association between myocardial injury and 1-year mortality. The causes of death, the diagnoses of the cardiologists, and interventions were determined for different levels of troponin elevation.

RESULTS

Postoperative myocardial injury was detected in 715 patients (22%) and was associated with 1-year all-cause mortality (relative risk [RR] 1.4, P = 0.004; RR 1.6, P < 0.001; and RR 2.2, P < 0.001 for minor, moderate, and major troponin elevation, respectively). Cardiac death within 1 year occurred in 3%, 5%, and 11% of patients, respectively, in comparison with 3% of the patients without myocardial injury (P = 0.059). A cardiac consultation was obtained in 290 of the 715 patients (41%). In 119 (41%) of these patients, the myocardial injury was considered to be attributable to a predisposing cardiac condition, and in 111 patients (38%), an intervention was initiated.

CONCLUSIONS

Postoperative myocardial injury was associated with an increased risk of 1-year all-cause but not cardiac mortality. A cardiac consultation with intervention was performed in less than half of these patients. The small number of interventions may be explained by a low suspicion of a cardiac etiology in most patients and lack of consensus for standardized treatment in these patients.

Thoracic epidural analgesia reduces myocardial injury in ischemic patients undergoing major abdominal cancer surgery

Background and objectives

Major abdominal cancer surgeries are associated with significant perioperative mortality and morbidity due to myocardial ischemia and infarction. This study examined the effect of perioperative patient controlled epidural analgesia (PCEA) on occurrence of ischemic cardiac injury in ischemic patients undergoing major abdominal cancer surgery.

Patients and methods

One hundred and twenty patients (American Society of Anesthesiologists grade II and III) of either sex were scheduled for elective upper gastrointestinal cancer surgeries. Patients were allocated randomly into two groups (60 patients each) to receive, besides general anesthesia: continuous intra and postoperative intravenous (IV) infusion with fentanyl for 72 h postoperatively (patient controlled intravenous analgesia [PCIA] group) or continuous intra and postoperative epidural infusion with bupivacaine 0.125% and fentanyl (PCEA group) for 72 h postoperatively. Perioperative hemodynamics were recorded. Postoperative pain was assessed over 72 h using visual analog scale (VAS). All patients were screened for occurrence of myocardial injury (MI) by electrocardiography, echocardiography, and cardiac troponin I serum level. Other postoperative complications as arrhythmia, deep venous thrombosis (DVT), pulmonary embolism, pneumonia, and death were recorded.

Results

There was a significant reduction in overall adverse cardiac events (myocardial injury, arrhythmias, angina, heart failure and nonfatal cardiac arrest) in PCEA group in comparison to PCIA group. Also, there was a significant reduction in dynamic VAS pain score in group PCEA in comparison to PCIA at all measured time points. Regarding perioperative hemodynamics, there was a significant reduction in intra-operative mean arterial pressure (MAP); and heart rate in PCEA group in comparison to PCIA group at most of measured time points while there was not a significant reduction in postoperative MAP and heart rate in the second and third postoperative days. The incidence of other postoperative complications such as DVT, pneumonia and in hospital mortality were decreased in PCEA group.

Conclusion

Perioperative thoracic epidural analgesia in patients suffering from coronary artery disease subjected to major abdominal cancer surgery reduced significantly postoperative major adverse cardiac events with better pain control in comparison with perioperative IV analgesia.

Troponin T in Patients with Traumatic Chest Injuries with and without Cardiac Involvement: Insights from an Observational Study

BACKGROUND

Serum troponin T (TnT) is a common marker of myocardial injury. However, its implication in the absence of clinical evidence of cardiac reason is not well established.

AIMS

The aim of this study was to identify the implications of positive TnT in traumatic chest injury (TCI) patients regardless of the cardiac involvement.

MATERIALS AND METHODS

We conducted a retrospective analysis of all TCI patients admitted to level 1 trauma center between 2008 and 2011. Patients who underwent TnT testing were divided into two groups: Group 1 (positive TnT) and Group 2 (negative TnT). The two groups were analyzed and compared, and multivariate regression analyses were performed to identify predictors of TnT positivity and mortality.

RESULTS

Out of 993 blunt TCI patients, 19.3% had positive TnT (Group 1). On comparison to Group 2, patients in Group 1 were 5 years younger and more likely to have head, cardiac, hepatic, splenic, and pelvic injuries, in addition to lung contusion. Positive TnT was associated with higher Injury Severity Score (ISS) (P = 0.001), higher chest Abbreviated Injury Score (AIS) (P = 0.001), and longer hospital stay (P = 0.03). In addition, Group 1 patients were more likely to undergo chest tube insertion, exploratory laparotomy, mechanical ventilation, and tracheostomy. Twenty patients had cardiac involvement, and of them 14 had positive TnT. Among 973 patients who showed no evidence of cardiac involvement, 178 had positive TnT (18.3%). There were 104 deaths (60% in Group 1). On multivariate regression analysis, the predictors of hospital mortality were positive TnT, head injury, and high ISS, whereas, the predictors of TnT positivity were cardiac, hepatic, and pelvic injuries; higher ISS; and age.

CONCLUSIONS

Positive TnT in blunt TCI patients is a common challenge, particularly in polytrauma cases. Patients with positive TnT tend to have the worst outcome even in the absence of clinical evidence of acute cardiac involvement. Positive TnT is also a reflection of the severity of chest or extrathoracic injuries; however, further prospective studies are warranted.

[Goal-directed hemodynamic therapy: Concepts, indications and risks]

Goal-directed hemodynamic therapy is becoming increasingly more interesting for anesthesiologists and intensive care physicians. Meta-analyses of studies evaluating perioperative therapy algorithms demonstrated a reduction of postoperative morbidity compared to the previous clinical practices. In this review article the basic concepts of goal-directed hemodynamic therapy and the principles of previously employed therapy algorithms are described and discussed. Furthermore, the questions of how these therapy strategies can be transferred into daily clinical practice and whether these therapeutic approaches might even bear risks for patients are elucidated.

Myocardial Injury After Noncardiac Surgery and its Association With Short-Term Mortality

Background—

To identify patients at risk for postoperative myocardial injury and death, measuring cardiac troponin routinely after noncardiac surgery has been suggested. Such monitoring was implemented in our hospital. The aim of this study was to determine the predictive value of postoperative myocardial injury, as measured by troponin elevation, on 30-day mortality after noncardiac surgery.

Methods and Results—

This observational, single-center cohort study included 2232 consecutive intermediate- to high-risk noncardiac surgery patients aged ≥60 years who underwent surgery in 2011. Troponin was measured on the first 3 postoperative days. Log binomial regression analysis was used to estimate the association between postoperative myocardial injury (troponin I level >0.06 μg/L) and all-cause 30-day mortality. Myocardial injury was found in 315 of 1627 patients in whom troponin I was measured (19%). All-cause death occurred in 56 patients (3%). The relative risk of a minor increase in troponin (0.07–0.59 μg/L) was 2.4 (95% confidence interval, 1.3–4.2; P <0.01), and the relative risk of a 10- to 100-fold increase in troponin (≥0.60 μg/L) was 4.2 (95% confidence interval, 2.1–8.6; P <0.01). A myocardial infarction according to the universal definition was diagnosed in 10 patients (0.6%), of whom 1 (0.06%) had ST-segment elevation myocardial infarction.

Conclusions—

Postoperative myocardial injury is an independent predictor of 30-day mortality after noncardiac surgery. Implementation of postoperative troponin monitoring as standard of care is feasible and may be helpful in improving the prognosis of patients undergoing noncardiac surgery.

Ascertainment of any and all neurologic and myocardial damage in carotid revascularization: the key to optimization?

The majority of carotid revascularization procedures performed at present are in asymptomatic patients. Since such procedures convey no immediate benefit, but rather protect from future hazard, optimization of procedural safety is mandatory. The authors focus their discussion on the methodologies that assess periprocedural myocardial damage and brain injury, as used in past clinical trials, from the fields of perioperative medicine and neurovascular imaging, and discuss methodologies to reduce both events in carotid revascularization.

Impact of troponin 1 on long-term mortality after emergency orthopaedic surgery in older patients

OBJECTIVES

To determine the association between post-operative troponin rises and longer term (2-year) mortality after emergency orthopaedic surgery in patients over 60 years of age.

METHODS

One hundred and two patients were recruited in 2006 and had inpatient troponin 1 measurements. These patients were followed up by a telephone call annually for complications.

RESULTS

At 2 years, 29.4% (30/102) of patients had died. Twenty-five patients (25/54 or 49.3%) with a troponin rise were dead at 2 years compared with five patients without a troponin rise (5/48 or 10.4%), which was significantly different P < 0.0001. Patients with a higher troponin level (>0.1 µg/L) were more likely to be dead at 2 years compared with those with a lower level of troponin. However, when adjusted for other comorbidities the association between troponin elevation and death at 2 years did not persist. Using Cox regression multivariate analysis, only one factor, sustaining an in-hospital cardiac event odds ratio 4.3 (95% confidence interval 1.8-10.3, P = 0.001), was associated with 2 years all-cause mortality . Furthermore, patients who sustained a symptomatic troponin rise (P < 0.0001) or asymptomatic troponin rise (P = 0.004) were more likely to have died at 2 years compared with those with no troponin rise. Three factors were significantly associated with a cardiac event during the second year: (i) post-operative troponin rise (P = 0.05); (ii) pre-morbid atrial fibrillation (P = 0.04); and (iii) post-operative renal failure (P < 0.001).

CONCLUSION

Elevated post-operative troponin levels are predictive of 1-year but not 2-year mortality in older patients undergoing emergency orthopaedic surgery.

Cardiac injury and troponin testing after orthopaedic surgery

BACKGROUND

Cardiac injury after orthopaedic surgery is an increasing problem particularly in an ageing population. The detection of cardiac injury has been aided by the use of cardiac troponins which has also raised questions about the utility of this enzyme in the post-operative setting.

OBJECTIVE

This review evaluates the diagnosis and pathophysiology of myocardial infarction after orthopaedic surgery and examines how myocardial injury is detected, with particular emphasis on the role of troponin testing.

SUBJECTS

Eight recent orthopaedic trials evaluating the use of troponin were identified in the literature and included in this review.

RESULTS

This review found that the diagnosis of myocardial infarction ismore difficult after surgery since classic symptoms may be atypical or absent. Therefore, there ismore reliance on the typical rise and fall in troponin to diagnose cardiac injury especially because electrocardiograph changes may be hard to detect. The pathophysiology of ischaemia after orthopaedic surgery may be different to ischaemia in the non-surgical setting. The incidence of troponin elevation is between 22 and 52.9% after emergency orthopaedic operations. Of note, patients sustaining a troponin elevation are often asymptomatic. Small studies have found troponin to be a prognostic marker of in-hospital cardiac complications, increased length of stay, increased likelihood of discharge to residential care and death at 1 year. No interventional studies have been published to date.

CONCLUSION

Cardiac injury is an important complication after orthopaedic surgery. Studies have found that troponin testing can detect asymptomatic cardiac injury. These patients are at risk of poorer outcomes and future research should be directed towards treatment of these patients.

[Perioperative myocardial damage in non-cardiac surgery patients]

Perioperative myocardial damage occurs with a high incidence depending on the operative procedure and the patients examined and is considered to be among the most relevant risk factors for increased perioperative morbidity and mortality in patients undergoing non-cardiac surgery. The pathophysiology of myocardial damage in the perioperative period is still not well understood. Both ischemia with and without acute coronary occlusion and non-ischemic stimuli can put a substantial strain on the heart in the perioperative period. However, in many cases the clinical presentation does not allow a clear differentiation between ischemic and non-ischemic myocardial damage. In the majority of cases perioperative myocardial infarctions occur with only mild or even without any clinical symptoms. This is probably due to a considerable difference in phenotype and pathophysiology between perioperative and non-perioperative myocardial infarctions. As a result of this unexplained etiology of perioperative myocardial infarction it remains an open question whether the contemporary diagnostic and therapeutic recommendations for the acute coronary syndrome can be extrapolated to the perioperative situation. The present review reflects the current state of knowledge and presents an optional approach to the diagnosis and therapy of perioperative myocardial injury.

[Cardiac biomarkers for diagnosis of myocardial infarction]

Diagnosis of postoperative myocardial infarction is often difficult, based on tools with a low sensitivity (clinical symptoms, EKG), or with a low specifity (old biomarkers, echocardiographic abnormalities) or inadequate for clinical practice (scintigraphy). Since 1995, clinicians may use more cardiospecific markers (troponin) allowing to modify strategy for postoperative myocardial infarction diagnosis. The aim of this review is to resume such an attitude.

Incidence of post-operative troponin I rises and 1-year mortality after emergency orthopaedic surgery in older patients

OBJECTIVES

to determine the incidence of post-operative troponin I rises and its association with 1-year all-cause mortality and cardiac events after emergency orthopaedic-geriatric surgery, which has not been studied before.

METHODS

one hundred and two patients over the age of 60 were recruited and followed up at 1 year. All consented to serial troponin I measurements peri-operatively.

RESULTS

the incidence of a troponin I rise post-operatively was 52.9%. Post-operative acute myocardial infarction was diagnosed in 9.8% and at 1 year, 70% of these patients were dead. At 1 year, 32.4% (33/102) had sustained a cardiac event (myocardial infarction, congestive cardiac failure, atrial fibrillation or major arrhythmia) and using multivariate analysis, post-operative troponin rise (OR 3.9, 95% CI 1.4-10.7, P = 0.008) was an independent predictor of this. Half of the patients with a troponin rise had a cardiac event compared to 18.8% without a rise. All-cause mortality was 20.6% at 1 year; 37% with an associated post-operative troponin rise died versus 2.1% without a rise (P < 0.0001). Using multivariate analysis, only two factors were associated with 1-year all-cause mortality: post-operative troponin rise (OR 12.0, 95% CI 1.4-104.8, P = 0.025) and sustaining a post-operative in-hospital cardiac event (OR 6.6, 95% CI 1.7-25.6, P = 0.006). Furthermore, patients with higher troponin levels had significantly worse survival.

CONCLUSIONS

there is a high incidence of post-operative troponin I rises in older patients undergoing emergency orthopaedic surgery with 1-year mortality and cardiac events being significantly increased in these patients. Future studies are needed to determine whether any intervention can improve outcome for these patients.

The unresolved issues with risk stratification and management of patients with coronary artery disease undergoing major vascular surgery

PURPOSE

The purpose of this article, with a specific focus on patients undergoing vascular surgery, is to review controversial issues related to mechanisms of perioperative myocardial infarction (MI), coronary artery disease detection, and strategies to reduce perioperative complications. We propose explanations for the many conflicting results that have recently emerged in the literature.Source documents: We searched MEDLINE and reviewed all relevant manuscripts and scientific statements regarding management of patients undergoing non-cardiac surgery.

PRINCIPAL FINDINGS

Identification and prevention of ischemia in patients undergoing vascular surgery remains controversial. While the identification of preoperative ischemia is a marker of a higher perioperative risk, the value of identifying such ischemia has been questioned. We believe this may be, at least in part, due to our limited understanding of perioperative MI. Appropriate management of patients, based on the results of such testing, is likely the key to improving outcomes, and deserves further investigation. Efforts aimed at reducing the ischemic consequences of severe coronary plaques (by revascularization or beta-blocker therapy) have yielded conflicting results. The use of high doses of preoperative beta-blocker therapy may be harmful. Some studies suggest a promising role for statin therapy. Benefits of acetylsalicylic acid must be weighted against the risk of bleeding.

CONCLUSION

Many questions remain unanswered about the impact of detecting inducible ischemia, and the role of revascularization or beta-blockers in patients undergoing vascular surgery. A better understanding of the pathophysiology of perioperative MI is critical, in order to identify the best approach to improve cardiac outcomes in these patients.

Concentrations of cardiac Troponin I before and after ovariohysterectomy in 46 female dogs with pyometra

BACKGROUND

Canine pyometra is a common disease in countries where routine spaying of young dogs is not common practice. This disease is known to lead to systemic inflammation potentially affecting multiple organs in the body, including the heart. Cardiac-specific Troponin I (cTnI) is a sensitive marker of myocardial cell damage, which can result from ischemia, trauma, toxins or inflammation. Dogs with pyometra are also exposed to anaesthesia which can potentially result in myocardial cell damage. The aims of the study were 1) to evaluate the occurrence of myocardial cell damage as indicated by increased serum concentrations of cTnI in dogs with pyometra and relate these to presence of systemic inflammation and 2) to evaluate the change in cTnI-concentrations after anaesthesia and surgery.

METHODS

Serum cTnI concentration was measured preoperatively and one day after surgery in 46 female dogs with pyometra and 15 female dogs that underwent surgery for other reasons (ovariohysterectomy and mammary tumours).

RESULTS

Forty-six female dogs of different breeds diagnosed with pyometra were included. The dogs had a median age of 8.5 years (IQR 7.5-10) and a median weight of 29 kg (IQR 9-32). Of the 46 dogs, 37 (80%) fulfilled the chosen criteria for systemic inflammatory response syndrome (SIRS) at inclusion. Thirteen (28%) of the dogs had increased cTnI concentrations (> 0.2 microg/l) before surgery and 18 (39%) had increased cTnI-concentrations the day after surgery. The cTnI concentrations in the 13 dogs with increased preoperative cTnI concentrations decreased in 8 dogs, increased in 4 dogs, and was unchanged in one dog. Seven dogs with nondetectable preoperative cTnI concentrations had increased postoperative concentrations. The only significant association between the studied laboratory or clinical variables (including SIRS) and cTnI concentration was preoperative percentage band neutrophils (PBN) and postoperative cTnI concentration (P = 0.016). In total, 20 dogs (43%) had increased pre- or postoperative cTnI concentrations. Seven dogs (15%) had pre-or postoperative concentrations of cTnI of 1.0 microg/l or higher.

CONCLUSION

Mild to moderate increases in cTnI appears to be common in dogs with pyometra before and after surgery, but the clinical importance of this finding is uncertain. None of the studied clinical variables were found to reliably predict increased preoperative cTnI concentrations. Because of the pre- and postoperative variation in cTnI concentrations, it was not possible to identify a negative effect of anaesthesia and surgery on myocardial cell integrity.

Troponin T as a predictive marker of morbidity in patients with fractured neck of femur

INTRODUCTION

This study aims prospectively to assess perioperative measurement of Troponin T, a marker of myocardial injury, as a predictor of morbidity and mortality in patients undergoing surgery for fractured neck of femur.

METHOD

All patients aged 65 years and over presenting with a fractured neck of femur over a 4-month period were initially included. Exclusion criteria were renal failure, polymyositis and conservative fracture management. Troponin T levels were measured on admission, day 1 and 2 post-surgery. According to local protocol, a level of >0.03 ng/mL was considered to be raised. Adverse outcome measures were cardiorespiratory events (myocardial infarction, congestive cardiac failure, unstable angina, major arrhythmias requiring treatment and pulmonary embolism), death and length of inpatient stay.

RESULTS

One hundred and twenty-nine patients presented with femoral neck fractures. 108 patients were included after application of the exclusion criteria. 42 (39%) showed a Troponin rise. Of these, 25 sustained one or more outcome complications versus seven with no rise (p<0.001). The mean hospital stay was 25.7 days for patients with elevated Troponin, 18.3 days in the normal group (p<0.012). There were nine deaths in the raised Troponin group, and five with no rise (p<0.05).

DISCUSSION

The principle causes of early death after hip fracture surgery are cardiac failure and myocardial infarction. Troponin T is a sensitive enzymatic marker of myocardial injury. The association between raised Troponin and hip fractures has not previously been made. In our series, 39% showed a perioperative Troponin rise. This was significantly associated with increased morbidity, mortality and longer hospitalisation. Many patients appear to be having silent events, causing significant morbidity. We recommend Troponin measurement in all patients to identify this risk and allow appropriate optimisation measures.

The one year incidence of postoperative myocardial infarction in an orthopedic population

The diagnosis of a postoperative myocardial infarction (PMI) is important in the orthopedic population because these events can be associated with significant cardiac morbidity. Plasma troponin I (cTnI) analysis has markedly increased our ability to detect myocardial damage. Using cTnI analysis for evidence of a PMI, we prospectively assessed all of our patients for (1) the 1-year incidence of PMI, (2) the clinical consequences of a PMI in relation to the level of the cTnI release, and (3) 6-month follow-up for cardiac complications. During a 12-month period, patients at risk for perioperative myocardial ischemia were assessed for a PMI by serum cTnI levels and daily serial ECGs. Patients with cTnI levels above the reference level (> or = 0.4 ng/ml) were also assessed for new cardiac regional wall motion abnormalities with an echocardiogram and 6-month postdischarge adverse cardiac events. Of the 758 patients who were assessed for a PMI, 49 patients had detectable cTnI levels (> or = 0.4 ng/ml); the incidence of a PMI was 0.6% of all surgical cases and 6.5% of those patients were at risk for a cardiac event. A PMI was more common after hip arthroplasty than other orthopedic procedures. Twenty-three patients had a cTnI level >3.0 ng/ml, and 74% these patients (17/23) had anginal symptoms and/or ischemic ECG changes. Nine of these patients (9/23) had new postoperative echocardiographic changes, five (5/23) required emergency transfer to a cardiac care unit, and 10 (10/23) had postoperative cardiac complications. In contrast, 15 patients with levels of cTnI <3.0 ng/ml and without ischemic ECG changes and/or anginal symptoms had no postoperative cardiac complications. Fourteen patients (14/47) had cardiac complications 6 months after discharge, including four cardiac deaths, one fatal stroke, and four patients with unstable anginal episodes that required a change in medical management, and six patients required coronary revascularization. Orthopedic surgical patients with cTnI level <3 ng/ml and without symptoms or ECG changes suggestive of myocardial ischemia (15/49) may have different risks than those with higher-level cTn1.

Methods of detecting atherosclerosis in non-cardiac surgical patients; the role of biochemical markers

Atherosclerosis is a common condition in both the developed and developing world and is now recognised to be an inflammatory condition leading to the development of ischaemic heart disease, cerebrovascular disease and peripheral vascular disease. Ischaemic heart disease is a major risk factor in the pathogenesis of perioperative adverse cardiovascular events which lead to significant morbidity and mortality within the high risk surgical patient population. Current methods of evaluating the likelihood of postoperative cardiovascular complications depend largely on risk scoring systems, and the preoperative assessment of the functional status of the cardiovascular system. However, the possible role of inflammation in the generation of atherosclerosis has led to the identification of several biochemical markers such as acute phase proteins, cellular adhesion molecules and cytokines. An alternative approach therefore is the measurement of preoperative levels of these biomarkers with the aim of assessing pre-existing disease activity. This review summarises the pathophysiology of atherosclerosis and perioperative myocardial infarction, and discusses the possible future role of biomarkers in the risk stratification of patients undergoing non-cardiac surgery.

Acute peri-operative beta blockade in intermediate-risk patients

Peri-operative beta-blockade has been shown to reduce the incidence of postoperative cardio- vascular complications including cardiac death in high-risk non-cardiac surgical patients. However, the recent analysis by Lindenauer et al. suggests that it is inappropriate to administer beta-blockers blindly to all surgical patients. In an attempt to determine the appropriateness of peri-operative beta-blocker administration across patients with a spectrum of cardiovascular risks, we have examined studies of intermediate-risk patient groups (that is those undergoing intermediate risk surgery or those with a Lee Revised Cardiac Risk Score of < or =2). We analysed data from randomised prospective studies of the effects of acute peri-operative beta-blockade on the incidence of peri-operative myocardial ischaemia. By examining the demographics and surgical interventions in these patients, we have compared these studies with other studies of peri-operative silent myocardial ischaemia representing patients of similar risk. We thus estimated the expected long-term postoperative cardiovascular complication rate associated with myocardial ischaemia in these patients in terms of number needed to treat for ischaemia prevention and for prevention of major cardiovascular complications. Prevention of peri-operative myocardial ischaemia with acute beta-blockade in non-cardiac surgical patients with 1-2 RCRI clinical risk factors can be achieved with a number needed to treat of 10. It is not associated with a significant increase in drug associated side-effects. However, acute beta-blockade shows no real benefit in the prevention of major cardiovascular complications in intermediate risk non-vascular surgical patients with a number-needed-to-treat of 833. Vascular surgical patients undergoing intermediate-risk surgery may benefit from the protective effects of acute peri-operative beta-blockade, however, with a number-needed-to-treat of 68 it would require a randomised clinical trial of over 24,000 patients to prove their efficacy.

Myocardial infarction in major noncardiac surgery: Epidemiology, pathophysiology and prevention

The number of subjects undergoing major noncardiac surgery who are at risk for perioperative myocardial infarction (MI) is growing worldwide.

It has been estimated that 500,000 to 900,000 patients suffer major perioperative cardiovascular complications every year, with consequent heavy, long-term prognostic implications and costs.

It is well known that perioperative MIs don’t share the same pathophysiology as nonsurgical MIs but the relative role of the different, potential triggers has not been completely clarified.

Many aspects of the perioperative management, including risk-stratification and prophylactic or postoperative interventions have also not been completely defined.

Throughout recent years many resources have been invested to clarify these aspects and experts have developed indices and algorithm-based strategies to better assess the cardiac risk and to guide the perioperative management.

The scope of the present review is to discuss the main aspects of perioperative MI in noncardiac surgery, with particular regard to epidemiology, pathophysiology, preoperative risk stratification, prophylaxis and therapy.

Should Pre-operative Troponin be a Standard Requirement in Patients Undergoing Major Lower Extremity Amputation?

OBJECTIVES

The objective of this study was to ascertain the benefit of routine pre-operative cardiac troponin I (cTnI) measurement in patients undergoing major lower extremity amputation for critical limb ischaemia.

DESIGN

This was a prospective, blinded observational study.

METHODS

All patients scheduled for lower extremity amputation, without evidence of unstable coronary artery disease were recruited prospectively over a period of 1 year. In addition to routine pre-operative evaluation, a blood sample was taken for measurement of serum cTnI. Post-operative screening was conducted for cardiac events with patients followed up to 6 weeks.

RESULTS

Ten of the 44 patients included suffered a non-fatal myocardial infarction or died from a cardiac cause post-operatively. A rise in pre-operative cTnI was associated with a very poor outcome (two cardiac deaths and one post-operative myocardial infarction) and was the only significant predictor of post-operative cardiac events.

CONCLUSION

Routine pre-operative cTnI measurement may be of use to identify patients at high risk of cardiac complication who would benefit from optimization of cardiac status or in whom surgery could be deferred.

Troponin increases in the critically injured patient: mechanical trauma or physiologic stress?

BACKGROUND

Serum troponin (Tn) is a sensitive and specific marker of myocardial injury. Tn increase after injury is usually attributed to mechanical chest trauma, but this relationship remains unproven. We sought to examine the etiologic factors and prognostic significance of increased Tn levels in a widely screened trauma population.

METHODS

We reviewed all trauma intensive care unit (ICU) admissions over a 5-year period with serial Tn I (TnI) measurements as part of a screening protocol. TnI was categorized as normal (0-1.2 microg/L), intermediate (1.3-5 microg/L), or high (>5 microg/L), and mortality rates were compared between groups. Multivariate regression analysis was used to identify independent predictors of TnI increase and mortality.

RESULTS

There were 1,081 patients identified. An increased TnI was found in 29% of patients. Mortality significantly increased from 16% in the normal group to 33 and 44% in the intermediate and high TnI groups, respectively. Independent predictors of an increased TnI were admission base excess (p = 0.04), Injury Severity Score (ISS) (p < 0.001), and Acute Physiology and Chronic Health Evaluation score (p < 0.001). Chest Abbreviated Injury Scale score and the presence or absence of severe chest injury did not independently predict TnI increase (p = 0.5 and 0.83). Any increase of TnI (>1.2 microg/L) was a strong independent predictor of mortality (odds ratio, 2.1; 95% confidence interval, 1.4-3.1) after controlling for age, sex, mechanism, base excess, Glasgow Coma Scale score, and ISS. Beta-blocker use was associated with a 50% reduction in mortality among patients with an increased Tn (38 versus 16%; p < 0.01).

CONCLUSIONS

Increased serum TnI after trauma is related to the degree of overall injury and physiologic stress and not mechanical chest trauma. Intermediate and high TnI increases are associated with increased mortality, which may be improved by selective use of beta-blockade.

Anesthésie et réanimation pour chirurgie réglée de l'anévrisme de l'aorte abdominale

OBJECTIVES

Patient scheduled for infrarenal abdominal aortic aneurysm surgery carries a high risk of cardiac or respiratory comorbidity. To outline the perioperative management for these patients.

METHODS

Review of the literature using MesH Terms "abdominal aortic aneurysm", "anesthesia", "analgesia" "critical care" and/or "surgery" in Medline database.

RESULTS

Cardiac preoperative evaluation and management have recently been reviewed. Intermediate and high-risk patients should undergo non-invasive cardiac testing to decide between a preoperative medical strategy (using betablocker+/-statin and aspirin) and an interventional strategy (coronary angioplasty or cardiac surgery). Perioperative myocardial ischaemia should also be investigated by clinical, electrocardiographic and biologic monitoring such as plasmatic troponin Ic dosage. Specific score could also assess the respiratory failure risk preoperatively. Epidural analgesia decreases this risk. There is no evidence that a pharmacological treatment decreases the incidence of acute renal failure after aortic surgery. Endovascular repair is actually recommended for older, higher-risk patients or patients with a hostile abdomen or other technical factors that may complicate standard open repair.

Predictors of long-term mortality and cardiac events in patients with known or suspected coronary artery disease who survive major non-cardiac surgery

The aim of this prospective study was to assess predictors of long-term outcome in patients with documented or suspected coronary artery disease who survive major non-cardiac surgery. The impact of patients' comorbidities, pre-operative heart rate variability and postoperative increase in cardiac troponin I on all-cause mortality and major cardiac events within 2 years was explored using multivariable logistic regression. Six of 173 patients died within the first month after surgery and were excluded from the study. Thirty-four of 167 patients (20%) died 1-24 months after surgery. Independent predictors of all-cause mortality were history of congestive heart failure (odds ratio 6.4 [95%, confidence interval 1.7-24]), pre-operatively depressed heart rate variability (odds ratio 6.4 [95%, confidence interval 1.9-21]), and age > 70 years (odds ratio 4.5 [95%, confidence interval 1.2-16]). In contrast, postoperative elevation of cardiac troponin I did not independently predict all-cause mortality or major cardiac events.