Increases in serum concentrations of cardiac proteins and the prediction of early postoperative cardiovascular complications in noncardiac surgery patients

Peri-operative cardiac biomarker screening: a narrative review

Peri-operative risk estimation has traditionally focused on assessing the likelihood of postoperative morbidity and mortality using pre-operative functional assessment. Although this strategy is currently recommended by most major society guidelines, contemporary evidence suggests that cardiac biomarker measurement has important advantages over pre-operative functional assessment. These advantages include superior predictive discrimination and inclusion of the postoperative course in risk estimation. In this review, we provide an overview of the evidence supporting the peri-operative utilisation, compare risk estimation methods and discuss which patients may benefit most from cardiac biomarker screening. We also discuss protocols for biomarker screening and management of patients with abnormal results.

[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.

Exercise capacity in children and adolescents with corrected congenital heart disease

Congenital heart disease promotes hemodynamic changes that can contribute to reduce exercise capacity. The aim of the study was to evaluate the exercise capacity of children and adolescents with cyanotic congenital heart disease and to assess respiratory muscle strength, plasma levels of B-type natriuretic peptide and ventricular ejection fraction, as well the associations between these variables. Cross-sectional study that evaluated 48 patients between 6 and 18 years-old that underwent a six-minute walk test (6MWT), respiratory muscle strength, dosage of B-type natriuretic peptide and echocardiography. The mean age was 13.3 ± 4.1 years, and the most prevalent heart disease was tetralogy of Fallot (54.2 %). The average distance walked was 452.7 ± 73.2 m, significantly below the predicted (69 %) (p < 0.001). The maximum inspiratory pressure was above the predicted result (111.4 %), average 58.2 ± 22.3 (p = 0.56), and the maximum expiratory pressure was 63.2 ± 23.3 cm H2O, significantly below the predicted (63 %) (p < 0.001). The level of B-type natriuretic peptide was elevated in all patients, with a median of 2087.17 (502.54-4,768.05). The ventricular ejection fraction showed a median of 65.9 (41-100). There was no correlation between the 6MWT, ventricular ejection fraction (r = -0.05; p = 0.72), inspiratory muscle strength (r = 0.03; p = 0.81), expiratory muscle strength (r = 0.09; p = 0.05) and B-type natriuretic peptide (r = -0.04; p = 0.77). Children and adolescents with cyanotic congenital heart disease present a lower exercise capacity and expiratory muscle strength. No associations were found between exercise capacity, respiratory muscle strength, B-type natriuretic peptide and left ventricular ejection fraction.

One dose of tranexamic acid is safe and effective in revision knee arthroplasty

Revision total knee arthroplasty (TKA) has been associated with an increased risk of perioperative blood loss. Tranexamic acid (TXA) has been proven to be safe and effective in preventing blood loss in primary TKA. The purpose of this study was to evaluate the effect of TXA on blood loss and transfusion rates in revision TKA. We performed a retrospective comparative study on 424 patients who had undergone revision TKA between January 2006 and March 2010. A total of 178 patients did not receive TXA while 246 patients received one intraoperative dose of 20mg/kg of TXA given prior to tourniquet release. There was a significant reduction in hemoglobin loss (42±16g/L vs 38±15g/L, P=0.005), transfusion rates (30.3% vs 16.7%, P=0.001) and average amount transfused (1.1±1.9units vs 0.5±1.1units, P=0.001) in the TXA group. There was no significant difference in recorded major adverse events with the administration of TXA.

Electrocardiograph Changes, Troponin Levels and Cardiac Complications After Orthopaedic Surgery

Introduction: The relationship between electrocardiograph (ECG) changes and troponin levels after the emergency orthopaedic surgery are not well characterised. The aim of this study was to determine the correlation between ECG changes (ischaemia or arrhythmia), troponin elevations perioperatively and cardiac complications. Materials and Methods: One hundred and eighty-seven orthopaedic patients over 60 years of age were prospectively tested for troponin I and ECGs were performed on the first 3 postoperative mornings or until discharge. Results: The incidences of pre- and postoperative troponin elevation were 15.5% and 37.4% respectively, the majority were asymptomatically detected. Most of the patients who sustained a troponin rise did not have any concomitant ECG changes (51/70 or 72.9%). Postoperative ECG changes were noted in 18.4% (34/185) and of those with ECG changes, slightly more than half (55.9%) had a troponin elevation. Most ECG changes occurred on postoperative day 1 and were non-ST elevation in type. ECG changes occurred more frequently with higher troponin levels. Postoperative troponin elevation (P = 0.018) and not preoperative troponin level (P = 0.060) was associated with ECG changes on univariate analysis. Two premorbid factors were predictors of postoperative ECG changes using multivariate logistical regression; age [odds ratio (OR), 1.05; 95% CI, 1.005 to 1.100, P = 0.029) and sex OR, 2.4; 95% CI, 1.069 to 5.446, P = 0.034). Twenty patients sustained postoperative cardiac complications; 9 (45%) were associated with ECG changes and 16 (80%) with postoperative troponin elevation. Pre- or postoperative troponin elevation better predicted cardiac complications compared with preoperative ECG changes. Conclusion: Electrocardiograph changes do not necessarily accompany troponin elevations after the emergency orthopaedic surgery but are more likely to have higher troponin levels. The best predictor of postoperative cardiac complications is troponin elevation. Key words: Cardiovascular, Fracture, Myocardial ischaemia, Myocardial infarction, Surgery

Mini-midvastus versus medial parapatellar approach in TKA: muscle damage and inflammation markers

The purpose of this prospective study was to analyze the biochemical markers of muscle damage and inflammation in patients treated with the mini-midvastus approach or the medial parapatellar approach for total knee arthroplasty. Of 60 patients who underwent unilateral total knee arthroplasty, 30 were treated with the mini-midvastus approach (MMV group) and 30 were treated with the medial parapatellar approach (MPP group). Serum creatine kinase, myoglobin, lactate dehydrogenase, glutamic oxaloacetic transaminase, C-reactive protein, interleukin-6, and interleukin-1β levels were measured preoperatively, immediately postoperatively (except for C-reactive protein level), and on postoperative days 1, 2, and 3. Student's t test, Pearson's chi-square test, and Fisher's exact test were used to compare the outcomes between the 2 groups. Compared with the MPP group, a significant increase in serum creatine kinase level existed in the MMV group on postoperative days 2 (P=.08) and 3 (P=.09) and cumulatively (P=.02). However, significantly elevated C-reactive protein and interleukin-6 levels existed in the MPP group.According to the serum creatine kinase levels, the mini-midvastus approach has no superiority over the medial parapatellar approach in terms of sparing muscle and may cause more muscle damage. Further study is warranted to determine the correlation between biochemical markers and functional deficits.

Comparison of soft-tissue serum markers in stable intertrochanteric fracture: dynamic hip screw versus proximal femoral nail—A preliminary study

DESIGN

Prospective randomised comparative study.

OBJECTIVES

To analyse and compare serum soft-tissue marker differences after dynamic hip screw (DHS)and proximal femoral nail (PFN) fixation of stable intertrochanteric fractures in the elderly.

MATERIALS AND METHODS

Twenty elderly patients (>60 years old) with a stable intertrochanteric fracture were enrolled in this study. Patients were divided into two groups of 10 each according to the device used (DHS or PFN). All 20 patients had a stable intertrochanteric fracture, and all were operated on by the same surgeon using minimal invasive approach. A biochemical comparison of soft-tissue serum markers was performed. The serum markers examined were haemoglobin (Hb), haematocrit (Hct), creatine kinase (CK), myoglobin (MYO), troponin I and C-reactive protein (CRP), and their levels were determined before surgery, and 1, 8, 16, 24, 36, 48 and 72 h after surgery. Differences between the DHS and PFN groups were compared.

RESULTS

No inter-group differences were observed with respect to preoperative demographics,operation time, incision length or blood loss. In terms of serum markers, both methods showed similar patterns of change for CK, MYO and CRP pre- to post-operatively. In addition, pre- and postoperative Hb and Hct levels were similar. Furthermore, no inter-group differences were observed between the absolute values of serum markers at any point.

CONCLUSION

The absolute values and temporal changes of serum markers were similar in the two study groups. These findings suggest that DHS and PFN fixation of stable intertrochanteric fractures produce similar levels of soft-tissue damage.

Perioperative management of the patient with cardiac disease

The overall incidence of perioperative death is relatively low. However, patients with coronary artery disease are at higher than average risk of perioperative cardiac complications. Thus, preoperative testing for cardiac disease should be done in certain patients in an effort to reduce postoperative mortality and morbidity. Patients who require emergent orthopaedic surgery are at greater risk of perioperative cardiac events than are those who undergo elective procedures. Certain modalities, such as beta blockers, statins, and alpha-2 agonists, may be started or continued in the postoperative period to further enhance cardiac function. We review the current recommendations for preoperative cardiac testing in orthopaedic patients and for perioperative management of orthopaedic patients with known cardiac disease.

The relationship between skeletal muscle serum markers and primary THA: a pilot study

Various reports confirm elevations in serum markers associated with skeletal muscle injury after orthopaedic surgery in the absence of overt clinical manifestations of myocardial injury. We therefore measured the influence surgical approach has on these serum markers after primary THA. We nonrandomly enrolled 30 nonconsecutive patients undergoing THA in three groups of 10 based on current surgical approaches used at our facility: (1) minimally invasive (MIS) modified Watson Jones approach; (2) miniposterior transmuscular approach (MIS-I); and (3) MIS-II incision. Blood samples for hemoglobin, hematocrit, cardiac troponin I, total creatine kinase, creatine phosphokinase, and serum myoglobin were obtained the morning before surgery as a baseline, immediately postoperatively, and 72 hours thereafter. We found reproducible trends in serum enzyme levels consistent with skeletal muscle damage resulting from primary THA. Troponin I remained normal in all but one patient indicating no myocardial contribution to measured serum enzyme levels. All three procedures resulted in similar trends in serum enzyme markers relevant to primary THA. Our preliminary data suggest no surgical approach appears to affect the degree of muscle trauma more or less than another.

[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.

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.

Ischemic heart disease

Because of changing demographics, increasing numbers of patients with IHD are presenting for noncardiac surgery, and the risks of perioperative morbidity and mortality are significant. The Lee Cardiac Risk Index is applicable in defining perioperative cardiac risk: however, ACC/AHA guidelines may not be applicable comprehensively. The role of biomarkers in risk stratification still needs to be defined. Structured management protocols that help assess, diagnose, and treat patients with IHD preoperatively are likely to help decrease postoperative morbidity and mortality, but clearly are not applicable to all patients. Augmented hemodynamic control with beta-blockers or alpha-2 agonists and modulating inflammation by statins can play an important role in improving outcomes in many patients with IHD; preoperative coronary revascularization may be of limited value. Intraoperative anesthetic management that minimizes hemodynamic perturbations is important; however, the choice of a particular technique typically is not critical. Of critical importance is the postoperative management of the patient. Postoperative myocardial injury should be identified, evaluated, and managed aggressively. Secondary stresses such as sepsis, extubation, and anemia, which can increase demand on the heart, should be treated or minimized. Clearly, optimal care of the patient with IHD entails closely coordinated assessment and management throughout the preoperative, intraoperative, and postoperative phases, if one is to optimize short- and long-term outcomes.

Evaluation of cardiac involvement following major orthopedic surgery

BACKGROUND

Cardiovascular morbidity is frequent after non-cardiac surgery and the early recognition of cardiac involvement is an essential tool for clinical risk stratification and management. The aim of this study was to investigate the behavior of traditional and emerging cardiac markers, including NT-prohormone-brain natriuretic peptide (NT-proBNP) and ischemia-modified albumin (IMA), in the perioperative period in patients undergoing major uncomplicated orthopedic surgery.

METHODS

A total of 37 patients undergoing major orthopedic surgery were longitudinally evaluated for NT-proBNP, IMA, cardiac troponin T (cTnT), creatine kinase isoenzyme MB and myoglobin 3 h before surgery and 4 and 72 h thereafter.

RESULTS

NT-proBNP values were significantly increased at 72 h postoperative compared to both 3 h preoperative and 4 h postoperative (NT-proBNP: 20 vs. 4.5 pmol/L, p<0.001 and 20 vs. 5.9 pmol/L, p<0.001). IMA levels were significantly increased at 4 and 72 h postoperative vs. 3 h preoperative (132 vs. 113 kU/L, p=0.02 and 151 vs. 113 kU/L, p<0.001). In a stepwise regression model, the perioperative liquid amount and degree of modification in postoperative creatinine levels (delta-creatinine) were independently related to the NT-proBNP increase.

CONCLUSIONS

The significant increase observed in NT-proBNP suggests that patients undergoing major uncomplicated orthopedic surgery may develop subclinical cardiac stress, presumably attributable to the considerable infusion of liquids. The clinical significance of this finding deserves further investigation, especially in patients at higher risk of heart failure.

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.

Long-term outcome of patients with perioperative myocardial infarction as diagnosed by troponin I after routine surgical coronary artery revascularization

OBJECTIVE

Diagnosis of perioperative myocardial infarction (P-MI) after coronary artery bypass graft (CABG) surgery traditionally relied on a combination of electrocardiographic and enzyme assay changes. Patients with Q-wave P-MIs who survive to hospital discharge have a poorer long-term prognosis. Troponin assays are more sensitive and specific for detecting minor P-MI, with an increased incidence of P-MI being reported. This study investigated if P-MI after CABG surgery, as defined by troponin-I isozyme (cTn-I), correlated with long-term outcome.

DESIGN

A prospective, observational study.

SETTING

A single-institution, cardiothoracic specialty hospital.

PARTICIPANTS

Seventy patients undergoing elective CABG surgery.

INTERVENTIONS

Patients (n = 70) were stratified into low-risk and high-risk groups according to the absence (cTn-I <15 microg/L) or presence (cTn-I >or=15 microg/L) of P-MI after CABG surgery. Patients with (n = 24) and without (n = 46) P-MI were then followed for 3 years after CABG surgery to determine the impact of cTn-I-defined P-MI on long-term outcome.

MEASUREMENTS AND MAIN RESULTS

Most patients felt that their quality of life and activity index had improved and that their symptoms of angina had lessened at 12-month follow-up. However, cardiovascular event-free survival was significantly less in patients with P-MI (p = 0.01) 3 years postoperatively. The incidence for cardiovascular events was 0.24 versus 0.65 (p = 0.049) in those patients without and with P-MI, respectively. The hazard ratio (2.9; 95% confidence interval, 1.3-9.4) for cardiovascular incidents was also significantly greater in patients with P-MI. More specifically, the incidence of arrhythmia was 2.4% versus 26.1% (p < 0.01), and the incidence of vascular events was 4.9% versus 26.1% (p = 0.02) in patients without and with P-MI, respectively.

CONCLUSIONS

It was shown that P-MI as defined by cTn-I is associated with an increased long-term incidence of adverse cardiovascular events. An elevated peak cTn-I level (>or=15 microg/L) identified patients at increased risk but did not have a powerful positive predictive value for either cardiovascular (48%) or vascular (26%) complications. However, a peak cTn-I <15 microg/L was a negative predictor of adverse vascular outcome (95%). This may have implications for postoperative patient follow-up.

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.

Integrin signaling in malignant melanoma

Cell adhesion and migration are essential for embryonic development, tissue regeneration, but also for tumor development. The physical link between the extracellular matrix (ECM) and the actin cytoskeleton is mainly mediated by receptors of the integrin family. Through signals transduced upon integrin ligation to ECM proteins, this family of proteins plays key roles in regulating tumor growth and metastasis as well as tumor angiogenesis. During melanoma development, changes in integrin expression, intracellular control of integrin functions and signals perceived from integrin ligand binding impact upon the ability of tumor cells to interact with their environment and enable melanoma cells to convert from a sessile, stationary to a migratory and invasive phenotype. Antagonists of several integrins are now under evaluation in clinical trials to determine their potential as therapeutics for malignant melanoma and other kinds of cancer.

Postoperative 12-lead ECG predicts peri-operative myocardial ischaemia associated with myocardial cell damage

Peri-operative myocardial ischaemia is the single most important risk factor for an adverse cardiac outcome after non-cardiac surgery. The present study examines whether intermittent 12-lead ECG recordings can be used as an early warning tool to identify patients suffering from peri-operative myocardial ischaemia and subsequent myocardial cell damage. Fifty-five vascular surgery patients at risk for or with a history of coronary artery disease were monitored for peri-operative myocardial ischaemia using intermittent 12-lead ECG recordings taken pre-operatively and at 15 min, 20 h, 48 h, 72 h and 84 h postoperatively. The effectiveness of the 12-lead ECG was gauged by examining concordance with continuous 3-channel Holter monitoring and capturing peri-operative myocardial ischaemia by serial analyses of creatine kinase myocardial band isoenzyme and cardiac troponin T and I. The incidence of peri-operative myocardial ischaemia detected by 12-lead ECG was 44% and was identifiable in most patients (88%) 15 min after surgery. The incidence of peri-operative myocardial ischaemia detected by continuous monitoring was 53%, with the most severe episodes occurring intra-operatively and during emergence from anaesthesia. The concordance of the 12-lead method with continuous monitoring was 72%. The concordance of creatine kinase myocardial band isoenzyme activity with the 12-lead method was 71% and with Holter monitoring 57%. The concordance of mass concentration of creatine kinase myocardial band with 12-lead ECG recordings was 75%, and the corresponding value for Holter monitoring was 68%. The concordance of cardiac troponin T and I levels with the 12-lead method was 85% and 87%, respectively, and concordance with Holter monitoring was 72% and 66%, respectively. The postoperative 12-lead ECG identified peri-operative myocardial ischaemia associated with subsequent myocardial cell damage in most patients undergoing vascular surgery.

Troponin T-values provide long-term prognosis in elderly patients undergoing non-cardiac surgery

BACKGROUND

The aim of this study was to evaluate the significance of elevated postoperative Troponin T (TnT) levels in an elderly population undergoing non-cardiac surgery.

METHODS

Five hundred and forty-six consecutive patients aged 70 years or older undergoing non-cardiac surgery of >30-min duration were enrolled in this prospective, observational study. A postoperative TnT measurement was obtained on the 5th to 7th postoperative day. Troponin T values greater than 0.02 ng ml(-1) were considered positive. Patients were followed over a 1-year period, and mortality and non-fatal cardiac events (acute myocardial infarction and coronary interventions) were recorded.

RESULTS

Troponin T concentrations greater than 0.02 ng ml(-1) were detected in 53 of the study subjects (9.7%). Eleven per cent of the patients with elevated TnT had electrocardiographic or clinical signs of myocardial ischemia. One year after surgery, 17 (32%) of the patients with abnormal TnT concentrations had died. In a multivariate Cox regression analysis adjusting for baseline and perioperative data, a TnT value >0.02 ng ml(-1) was an independent correlate of the mortality adjusted hazard ratio (HR): 14.9 (95% CI 3.7-60.3). Other independent predictors of death were tachycardia (HR, 14.9 95% CI 3.45-64.8), ASA 4 (HR, 8.1 95% CI 1.3-50.0), reoperation (HR, 6.4 95% CI 1.1-36.9), and use of diuretics (HR, 4.2 95% CI 1.3-13.8).

CONCLUSION

We conclude that elevated TnT levels in the postoperative period confer a 15-fold increase in mortality during the first year after surgery. Our findings also provide evidence that silent myocardial ischemia is common in an elderly population. Routine perioperative surveillance for TnT might therefore be of use in detecting patients at an increased risk of mortality during the first postoperative year.

Postoperative troponin-T predicts prolonged intensive care unit length of stay following cardiac surgery*

OBJECTIVE

To evaluate the use of postoperative cardiac troponin T (cTnT) for the prediction of prolonged intensive care unit length of stay following cardiac surgery.

DESIGN

Prospective, single-center, observational cohort study of patients following cardiac surgical procedures. The enrollment period was from October through December 2000. Patients were enrolled on admission to the intensive care unit and followed until hospital discharge.

SETTING

The cardiac surgical intensive care unit of the Massachusetts General Hospital.

PATIENTS

A total of 222 consecutive patients were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Perioperative clinical factors and serum concentrations of cTnT measured every 8 hrs after surgery were recorded. These clinical factors and the results of serum cTnT measurement were correlated with the need for prolonged intensive care unit length of stay (defined as >24 hrs). Univariable analysis identified factors predictive of prolonged intensive care unit length of stay. Stepwise logistic regression identified independent predictors of prolonged intensive care unit length of stay. Multiple linear regression was used to explore the direct relationship between cTnT concentrations at several postoperative time points and intensive care unit length of stay. At each time point assessed, cTnT concentrations from patients requiring a prolonged intensive care unit length of stay were significantly higher (all p <.001) than in those individuals with normal length of stay. In contrast, creatine kinase isoenzymes were not significantly different between patients with normal or prolonged intensive care unit length of stay. Multivariable analysis demonstrated that an immediate postoperative cTnT concentration > or =1.58 ng/mL was the strongest predictor of a prolonged intensive care unit length of stay (odds ratio, 5.6; 95% confidence interval, 2.9-10.8). Multiple linear regression analysis revealed that intensive care unit length of stay increased by 0.32 days with each incremental 1.0 ng/mL increase in cTnT measured at 18-24 hrs postprocedure.

CONCLUSIONS

Elevated postoperative cTnT concentrations can prospectively identify patients requiring prolonged intensive care unit length of stay after cardiac surgery.

QTc dispersion is prolonged in patients with early postoperative adverse cardiovascular events and those with silent myocardial ischemia

OBJECTIVE

To determine if increased QT interval dispersion (corrected and not corrected for heart rate) is associated with perioperative silent myocardial ischemia or postoperative adverse cardiovascular events.

DESIGN

Blinded retrospective observational study.

SETTING

University hospital.

PARTICIPANTS

One hundred eighty-one perioperative patients receiving general anesthesia for elective major vascular or orthopedic surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

QT dispersion, corrected and uncorrected for heart rate, was prolonged in patients suffering significant myocardial ischemia up to 48 hours assessed by Holter ECG monitoring, for early cardiac morbidity and all early cardiac events (including mortality) up to 1 month postoperatively. There were no significant changes in patients showing early cardiovascular mortality or late cardiac morbidity or mortality between 1 and 12 months postoperatively. Morbidity and mortality were determined from clinical notes, laboratory investigations, and autopsy when available. QT dispersion performed poorly as a screening test to identify those who subsequently developed early adverse cardiovascular outcomes.

CONCLUSIONS

QT dispersion is prolonged in those at risk of early adverse cardiovascular events but is a poor screening tool.

Effect of chronic β-blockade on peri-operative outcome in patients undergoing non-cardiac surgery: an analysis of observational and case control studies*

Little is known about the effect of chronic beta-adrenoceptor antagonist therapy during the peri-operative period in patients undergoing non-cardiac surgery. We conducted a literature review to identify studies examining the relationship between chronic therapy and adverse peri-operative outcome. Eighteen studies were identified in which it was possible to ascertain the incidence of adverse cardiac outcomes in those patients who were and were not receiving chronic beta-blocker therapy. None of the studies demonstrated a protective effect of chronic beta-blockade. The results of these studies were then combined and a cumulative odds ratio calculated for the likelihood of myocardial infarction, cardiac death and major cardiac complications. Patients receiving chronic beta-blocker therapy were more likely to suffer a myocardial infarction (p < 0.05). These findings differ from the published effects of acute beta-blockade. Reasons for this discrepancy are considered.

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

We have previously demonstrated that the peri-operative measurement of increased serum concentrations of the cardiac markers troponins I and T and creatine kinase-MB can be predictors of major cardiovascular outcomes (including cardiac death) at 3 months after surgery. In the present study, we have followed the postoperative course of 157 patients undergoing major vascular surgery or major joint arthroplasty to 1 year using a patient questionnaire, general practitioner follow-up and case-notes review. Increased postoperative marker concentrations were defined as values greater than the upper reference limit. Increases in troponin I and troponin T concentrations, as well as a single elevated creatine kinase-MB and two successively elevated creatine kinase-MB concentrations were measured in 12, 13, 33 and 15 patients respectively. Thirty-nine major adverse cardiac outcomes were recorded (cardiac death, myocardial ischaemia, congestive cardiac failure, unstable angina, cerebrovascular accident and major arrhythmias needing active treatment). There was no association between increases in any of these cardiac markers and cardiac death to 1 year. However, increases in troponin I and both a single elevated creatine kinase-MB and two successively elevated creatine kinase-MB concentrations were associated with an increased incidence of major cardiac outcomes, including cardiac death, to 1 year (odds ratio [95% confidence intervals] = 4.19 [1.16-14.87], 3.97 [1.65-9.44] and 5.19 [1.60-16.22], respectively).

Assessment and management of patients with ischemic heart disease

OBJECTIVE

Review the perioperative management of patients who are scheduled for noncardiac surgery.

DATA SOURCE

Review of literature (PubMed, MEDLINE).

CONCLUSIONS

Patients with ischemic heart disease who undergo noncardiac surgery are at significant risk of perioperative cardiac morbidity and mortality. Recent joint guidelines from the American College of Cardiology and American Heart Association have significantly streamlined the preoperative evaluation processes. Augmented hemodynamic control with intensive perioperative pharmacologic therapy with beta-blockers and possibly alpha-2 agonist has been shown to improve perioperative cardiovascular outcomes. However, translating this information to clinical practice continues to be a challenge and requires a multi- disciplinary approach. A particular intraoperative anesthetic technique is unlikely to influence perioperative cardiac morbidity and mortality. Postoperative management with goals of decreasing hemodynamic stress is important in patients with ischemic heart disease. Diagnosis and management of perioperative myocardial infarction continues to be a challenge. However, use of cardiac specific biomarkers should improve the diagnostic process.

Perioperative myocardial infarction in noncardiac surgery: the diagnostic and prognostic role of cardiac troponins

Despite the number of technologies used, the diagnosis of perioperative myocardial infarction is still a challenge. Studies conducted in surgical series have demonstrated that cardiac troponins (cTns) have both a superior diagnostic sensitivity and specificity, compared with other traditional techniques, and an independent power to predict short- and long-term prognosis. Nevertheless, some points need to be clarified. They include the usefulness of cTns in patients with end-stage renal failure; the standardization of the cTns cut-off for the diagnosis of myocardial injury; the timing of postoperative blood samplings; the cost-effectiveness of a screening in asymptomatic patients; and the possible therapeutic strategies.