Cardiac biomarkers in the prediction of risk in the non-cardiac surgery setting

Study protocol for an observational cohort evaluating incidence and clinical relevance of perioperative elevation of high-sensitivity troponin I and N-terminal pro-brain natriuretic peptide in patients undergoing lung resection

INTRODUCTION

Myocardial injury after non-cardiac surgery has been defined as myocardial injury due to ischaemia, with or without additional symptoms or ECG changes occurring during or within 30 days after non-cardiac surgery and mainly diagnosed based on elevated postoperative cardiac troponin (cTn) values. In patients undergoing thoracic surgery for lung resection, only postoperative cTn elevations are seemingly not enough as an independent predictor of cardiovascular complications. After lung resection, troponin elevations may be regulated by mechanisms other than myocardial ischaemia. The combination of perioperative natriuretic peptide measurement together with high-sensitivity cTns may help to identify changes in ventricular function during thoracic surgery. Integrating both cardiac biomarkers may improve the predictive value for cardiovascular complications after lung resection. We designed our cohort study to evaluate perioperative elevation of both high-sensitivity troponin I (hs-TnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in patients undergoing lung resection and to establish a risk score for major cardiovascular postoperative complications.

METHODS AND ANALYSIS

We will conduct a prospective, multicentre, observational cohort study, including 345 patients undergoing elective thoracic surgery for lung resection. Cardiac biomarkers such as hs-TnI and NT-proBNP will be measured preoperatively and at postoperatively on days 1 and 2. We will calculate a risk score for major cardiovascular postoperative complications based on both biomarkers' perioperative changes. All patients will be followed up for 30 days after surgery.

ETHICS AND DISSEMINATION

All participating centres were approved by the Ethics Research Committee. Written informed consent is required for all patients before inclusion. Results will be disseminated through publication in peer-reviewed journals and presentations at national or international conference meetings.

TRIAL REGISTRATION NUMBER

NCT04749212.

Non-cardiac surgery in patients with valvular heart disease

In patients with significant valvular heart disease (VHD) undergoing non-cardiac surgery (NCS), perioperative adverse cardiac events are a relevant issue. Although postoperative outcomes can be adversely affected by valve-related haemodynamic instability, recommended perioperative risk scores prioritise the risk of the surgical procedure and the presence of cardiovascular risk factors, neglecting the presence or extent of VHD. Perioperative management and anaesthetic approach should focus on the underlying type and severity of VHD, the compensatory mechanisms deployed by left ventricle and right ventricle and the type and risk of NCS. Due to the lack of randomised trials investigating different therapeutic approaches of valvular intervention prior to NCS, recommendations mainly rely on consensus opinion and inference based on large observational registries. As a general rule, valvular intervention is recommended prior to NCS in symptomatic patients or in those who meet standard criteria for cardiac intervention. In the absence of such conditions, it is reasonable to perform NCS with tailored anaesthetic management and close invasive perioperative haemodynamic monitoring. However, patient-specific management strategies should be discussed with the heart team preoperatively. Symptomatic patients with severe VHD or those undergoing high-risk NCS should ideally be treated at a high-volume medical centre that is equipped to manage haemodynamically complex patients during the perioperative period.

Impact of cardiopulmonary bypass and surgical complexity on plasma soluble urokinase-type plasminogen activator receptor levels after cardiac surgery

BACKGROUND

Circulating soluble urokinase plasminogen activator receptor (suPAR) is a marker of inflammation with prognostic value for elevated risk of morbidity and mortality. It has not yet been shown how the inflammatory process induced by cardiac surgery affects suPAR concentrations postoperatively.

METHODS

In a prospective observational study, plasma suPAR levels were measured in 30 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB), pre-, peri, post-operatively, and 3-5 days after surgery. Fifteen patients underwent coronary artery bypass grafting (CABG) and 15 underwent complex procedures with longer CPB duration. Concentrations of suPAR at each time point were compared to the preoperative levels and compared between the two groups.

RESULTS

In both groups, plasma suPAR concentrations were significantly higher on the first postoperative day (3.27 (interquartile range (IQR) 2.75-3.86) µg/L compared to baseline (2.62 (1.98-3.86)) µg/L, p < .001. There were no significant differences in suPAR concentrations between the groups at any time point. Preoperatively, the median suPAR concentration was 2.57 (2.01-3.60) µg/L in the CABG group versus 2.67 (1.89-3.97) µg/L in the complex group (p = .567). At ICU arrival 2.48 (2.34-3.23) µg/L versus 2.73 (2.28-3.44) µg/L in CABG and complex patients, respectively (p = .914). There was no difference in suPAR concentrations between the groups on postoperative day 1 (3.34 (2.89-3.89) versus 3.19 (2.57-3.62) p = .967) or 3-5 days after surgery (2.72 (1.98-3.16) versus 2.96 (2.39-4.28) p = .085.

CONCLUSIONS

After a transient rise on the first postoperative day, the suPAR levels returned to the preoperative levels by the third postoperative day. There was no significant difference in suPAR levels between the routine CABG and complex group with longer CPB time.

Etomidate vs propofol in coronary heart disease patients undergoing major noncardiac surgery: A randomized clinical trial

BACKGROUND

The ideal depth of general anesthesia should achieve the required levels of hypnosis, analgesia, and muscle relaxation while minimizing physiologic responses to awareness. The choice of anesthetic strategy in patients with coronary heart disease (CHD) undergoing major noncardiac surgery is becoming an increasingly important issue as the population ages. This is because general anesthesia is associated with a risk of perioperative cardiac complications and death, and this risk is much higher in people with CHD.

AIM

To compare hemodynamic function and cardiovascular event rate between etomidate- and propofol-based anesthesia in patients with CHD.

METHODS

This prospective study enrolled consecutive patients (American Society of Anesthesiologists grade II/III) with stable CHD (New York Heart Association class I/II) undergoing major noncardiac surgery. The patients were randomly allocated to receive either etomidate/remifentanil-based or propofol/remifentanil-based general anesthesia. Randomization was performed using a computer-generated random number table and sequentially numbered, opaque, sealed envelopes. Concealment was maintained until the patient had arrived in the operating theater, at which point the consulting anesthetist opened the envelope. All patients, data collectors, and data analyzers were blinded to the type of anesthesia used. The primary endpoints were the occurrence of cardiovascular events (bradycardia, tachycardia, hypotension, ST-T segment changes, and ventricular premature beats) during anesthesia and cardiac troponin I level at 24 h. The secondary endpoints were hemodynamic parameters, bispectral index, and use of vasopressors during anesthesia.

RESULTS

The final analysis included 40 patients in each of the propofol and etomidate groups. The incidences of bradycardia, hypotension, ST-T segment changes, and ventricular premature beats during anesthesia were significantly higher in the propofol group than in the etomidate group (P < 0.05 for all). The incidence of tachycardia was similar between the two groups. Cardiac troponin I levels were comparable between the two groups both before the induction of anesthesia and at 24 h after surgery. When compared with the etomidate group, the propofol group had significantly lower heart rates at 3 min after the anesthetic was injected (T₁) and immediately after tracheal intubation (T₂), lower systolic blood pressure at T₁, and lower diastolic blood pressure and mean arterial pressure at T₁, T₂, 3 min after tracheal intubation, and 5 min after tracheal intubation (P < 0.05 for all). Vasopressor use was significantly more in the propofol group than in the etomidate group during the induction and maintenance periods (P < 0.001).

CONCLUSION

In patients with CHD undergoing noncardiac major surgery, etomidate-based anesthesia is associated with fewer cardiovascular events and smaller hemodynamic changes than propofol-based anesthesia.

Intraoperative Troponin Elevation in Liver Transplantation Is Independently Associated With Mortality: A Prospective Observational Study

Intraoperative factors implicated in postoperative mortality after liver transplantation (LT) are poorly understood. Because LT is a particularly demanding procedure, we hypothesized that intraoperative myocardial injury may be frequent and independently associated with early postoperative outcomes. We aimed to determine the association between intraoperative high-sensitivity troponin (hsTn) elevation during LT and 30-day postoperative mortality. A total of 203 adult patients undergoing LT were prospectively included in the cohort and followed during 1 year. Advanced hemodynamic parameters and serial high-sensitivity troponin T (hsTnT) measurements were assessed at 6 intraoperative time points. The optimal hsTnT cutoff level for intraoperative troponin elevation (ITE) was identified. Patients were classified into 2 groups according to the presence of ITE. Independent impact of ITE on survival was assessed through survival curves and multivariate Cox regression analysis. Intraoperative cardiac function was compared between groups. Troponin levels increased early during surgery in the ITE group. Troponin values at abdominal closure were associated with 30-day mortality (area under the receiver operating caracteristic curve, [AUROC], 0.73; P = 0.005). Patients with ITE showing values of hsTnT ≥61 ng/L at abdominal closure presented higher 30-day mortality (29.6% versus 3.4%; P < 0.001). ITE was independently associated with 30-day mortality (hazard ratio, 3.8; 95% confidence interval, 1.1-13.8; P = 0.04) and with worse overall intraoperative cardiac function. The hsTnT upper reference limit showed no discriminant capacity during LT. Intraoperative myocardial injury identified by hsTn elevation is frequently observed during LT, and it is associated with myocardial dysfunction and short-term mortality. Determinations of hsTn may serve as a valuable intraoperative monitoring tool during LT.

Meta-analysis of preoperative high-sensitivity cardiac troponin measurement in non-cardiac surgical patients at risk of cardiovascular complications

Background

Patients undergoing major non-cardiac surgery are at risk of cardiovascular complications. Raised levels of high-sensitivity troponin are frequently detected before operation among these patients. However, the prognostic value of high-sensitivity troponin in predicting postoperative outcomes remains unclear.

Methods

A systematic search of PubMed, Embase and Science Citation Index Expanded was undertaken for observational studies published before March 2018 that reported associations between raised preoperative levels of high-sensitivity troponin and postoperative major adverse cardiac events and/or mortality after non-cardiac surgery. Meta-analyses were performed, where possible, using random-effects models.

Results

Seven cohort studies with a total of 4836 patients were included. A raised preoperative high-sensitivity troponin level was associated with a higher risk of short-term major adverse cardiac events (risk ratio (RR) 2·92, 95 per cent c.i. 1·96 to 4·37; I2 = 82·6 per cent), short-term mortality (RR 5·39, 3·21 to 9·06; I2 = 0 per cent) and long-term mortality (RR 2·90, 1·83 to 4·59, I2 = 74·2 per cent). The addition of preoperative high-sensitivity troponin measurement provided improvements in cardiovascular risk discrimination (increase in C-index ranged from 0·058 to 0·109) and classification (quantified by continuous net reclassification improvement) compared with Lee's Revised Cardiac Risk Index alone. There was substantial heterogeneity and inadequate risk stratification analysis in the included studies.

Conclusion

Raised preoperative levels of high-sensitivity troponin appear to represent a risk for postoperative major adverse cardiac events and mortality. Further study is required before high-sensitivity troponin can be used to predict risk stratification in routine clinical practice.

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.

Who is a high-risk surgical patient?

PURPOSE OF REVIEW

Timely identification of high-risk surgical candidates facilitate surgical decision-making and allows appropriate tailoring of perioperative management strategies. This review aims to summarize the recent advances in perioperative risk stratification.

RECENT FINDINGS

Use of indices which include various combinations of preoperative and postoperative variables remain the most commonly used risk-stratification strategy. Incorporation of biomarkers (troponin and natriuretic peptides), comprehensive objective assessment of functional capacity, and frailty into the current framework enhance perioperative risk estimation. Intraoperative hemodynamic parameters can provide further signals towards identifying patients at risk of adverse postoperative outcomes. Implementation of machine-learning algorithms is showing promising results in real-time forecasting of perioperative outcomes.

SUMMARY

Perioperative risk estimation is multidimensional including validated indices, biomarkers, functional capacity estimation, and intraoperative hemodynamics. Identification and implementation of targeted strategies which mitigate predicted risk remains a greater challenge.

Diagnosing Perioperative Cardiovascular Risks in Noncardiac Surgery Patients

Every year, over 200 million adults are undergoing noncardiac surgery. These noncardiac surgery patients may face the risk of cardiac mortality and morbidity during the perioperative and recovery periods. Around ten million patients who underwent noncardiac surgery experience cardiac complications within the first 30 days of the postoperative period; the complications are myocardial infarction, cardiac death, and cardiac arrest. This cardiovascular risk is mostly faced by the patients having cerebrovascular or cardiac disease and the patients with the age greater than 50 years. Monitoring and treating cardiac diseases with a suitable biomarker during the perioperative period is necessary for the early recovery of noncardiac surgery patients. This review discussed the risk factors and the key guidelines to avoid the cardiovascular risks during the perioperative period of noncardiac surgery patients. In addition, the biomarkers and identification strategies for cardiac diseases are discussed.

Myocardial injury in elderly patients after abdominal surgery

BACKGROUND

The development of sensitive myocardial-specific cardiac biomarkers allows for detection of very small amounts of myocardial injury or necrosis. Myocardial injury (MI) as a prelude of the serious perioperative complication myocardial infarction, should be paid more attention, especially in elderly susceptible patients. Myocardial injury after abdominal surgery in elderly patients has not been described yet. The objectives of this study were to identify the incidence, predictors, characteristics and the impact of MI on outcome in elderly patients underwent abdominal surgery.

METHODS

Patients aged  ≥ 65 who underwent abdominal surgery longer than 2 h between January 2016 and March 2017 were reviewed. Patients with peak troponin I level of 0.04 ng/ml or greater (abnormal laboratory threshold) within once-administration-period and without non-ischemia troponin elevation proof (e.g., sepsis) were assessed for characteristics and prognosis. Risk factors of MI were determined by multivariable regression.

RESULTS

Among 285 patients with whole information, 36 patients (12.6%) suffered MI, only 2 patients (0.7%) fulfilled definition of myocardial infarction. With most of them occurred within first 7 days after surgery. Multivariable analysis showed that coronary artery disease (CAD) history [odds ratio (OR) 2.817, P = 0.015], non-laparoscopic surgery (OR 5.181, P = 0.030), blood loss ≥ 800 ml (OR 3.430, P = 0.008), non-venous maintain (OR 2.105, P = 0.047), and infection (OR 4.887, P = 0.008) as risk factors for MI. MI was associated with longer hospital stay (P = 0.006), more cardiac consultation (P = 0.011), higher infection(P = 0.016) and reoperation(P = 0.026) rate.

CONCLUSION

MI is common in elderly patients who underwent abdominal surgery, while myocardial infarction is infrequent. They are both associated with risk factors and worse prognosis. MI deserves more attention especially in elderly patients. Troponin I measurement is a useful test after massive surgery, which can help risk-stratifying patients, effective preventing, prompt managing and predicting outcomes. Routine monitoring of cardiac biomarkers especially within 7 days after abdominal surgery in elderly patients is recommended.

Association of renin angiotensin antagonists with adverse perioperative events in patients undergoing elective orthopaedic surgery: a case-control study

BACKGROUND

Renin angiotensin antagonists (RAA) may block protective vasopressor responses during surgery. Evidence linking RAA with intraoperative hypotension and perioperative adverse events is conflicting.

AIM

To compare the incidence of intraoperative hypotension and adverse events between patients receiving or not receiving RAA.

METHODS

This is a retrospective case-control study of 258 consecutive patients who underwent elective total knee or hip replacement between 1 January 2013 and 31 August 2016 and who were chronically prescribed a single blood pressure-lowering agent up to the time of surgery. Primary outcome measures were differences between patients receiving RAA (cases; n = 129) and patients receiving non-RAA medications (controls; n = 129) in incidence of intraoperative hypotension (systolic blood pressure <90 mmHg), perioperative acute kidney injury (AKI, >30% increase in serum creatinine from baseline on Day 1 post-operatively) and new onset major adverse cardiac or cerebrovascular events (MACCE) or in-hospital death over 72 h post-operatively.

RESULTS

Patients receiving RAA had significantly higher preoperative systolic blood pressure, greater prevalence of hypertension and chronic kidney disease, lower prevalence of ischaemic heart disease and lower cardiac risk compared to controls. Age, gender, type of operation, operative fitness, mode and duration of anaesthesia and prevalence of other types of cardiovascular disease, dyslipidaemia and diabetes were similar between groups. Compared to controls, patients receiving RAA had higher incidence of intraoperative hypotension (76.0 vs 45.9%, P < 0.001), AKI (11.6 vs 1.6%, P = 0.002) and MACCE (6.2 vs 0%, P = 0.007), with all adverse events associated with intraoperative hypotension.

CONCLUSION

This study provides further observational evidence of RAA-induced harm in patients undergoing elective surgery, although determining benefits and harms of preoperative withdrawal of RRA requires prospective randomised trials.

Development of the Combined Assessment of Risk Encountered in Surgery (CARES) surgical risk calculator for prediction of postsurgical mortality and need for intensive care unit admission risk: a single-center retrospective study

INTRODUCTION

Accurate surgical risk prediction is paramount in clinical shared decision making. Existing risk calculators have limited value in local practice due to lack of validation, complexities and inclusion of non-routine variables.

OBJECTIVE

We aim to develop a simple, locally derived and validated surgical risk calculator predicting 30-day postsurgical mortality and need for intensive care unit (ICU) stay (>24 hours) based on routinely collected preoperative variables. We postulate that accuracy of a clinical history-based scoring tool could be improved by including readily available investigations, such as haemoglobin level and red cell distribution width.

METHODOLOGY

Electronic medical records of 90 785 patients, who underwent non-cardiac and non-neuro surgery between 1 January 2012 and 31 October 2016 in Singapore General Hospital, were retrospectively analysed. Patient demographics, comorbidities, laboratory results, surgical priority and surgical risk were collected. Outcome measures were death within 30 days after surgery and ICU admission. After excluding patients with missing data, the final data set consisted of 79 914 cases, which was divided randomly into derivation (70%) and validation cohort (30%). Multivariable logistic regression analysis was used to construct a single model predicting both outcomes using Odds Ratio (OR) of the risk variables. The ORs were then assigned ranks, which were subsequently used to construct the calculator.

RESULTS

Observed mortality was 0.6%. The Combined Assessment of Risk Encountered in Surgery (CARES) surgical risk calculator, consisting of nine variables, was constructed. The area under the receiver operating curve (AUROC) in the derivation and validation cohorts for mortality were 0.934 (0.917-0.950) and 0.934 (0.912-0.956), respectively, while the AUROC for ICU admission was 0.863 (0.848-0.878) and 0.837 (0.808-0.868), respectively. CARES also performed better than the American Society of Anaesthesiologists-Physical Status classification in terms of AUROC comparison.

CONCLUSION

The development of the CARES surgical risk calculator allows for a simplified yet accurate prediction of both postoperative mortality and need for ICU admission after surgery.

High levels of preoperative and postoperative N terminal B-type natriuretic propeptide influence mortality and cardiovascular complications after noncardiac surgery: A prospective cohort study

BACKGROUND

Major noncardiac surgery is associated with a 5% incidence of serious cardiovascular complications and with a 1 to 2% probability of death from cardiac causes. Over the last few decades, researchers have assessed the perioperative predictive power of several risk indices. Research is currently focused on the evaluation of biomarkers.

OBJECTIVES

The objective was to determine the incidence of high serum levels of N terminal B-type natriuretic propeptide (NT-proBNP) before and after surgery in adults undergoing elective major noncardiac procedures and to evaluate its relationship with mortality and cardiovascular complications occurring up to 30 days after surgery.

DESIGN

Prospective cohort study.

SETTING

Enrolment was undertaken at a university hospital from October 2011 to July 2013.

PATIENTS

A total of 304 adults with cardiovascular risk factors who underwent noncardiac elective surgery.

MAIN OUTCOME MEASURES

The relationship between preoperative and postoperative NT-proBNP serum levels and the emergence of cardiovascular complications, including all-cause mortality, during the first 30 days after surgery.

RESULTS

The incidence of cardiovascular complications was 7.8% (n = 25), and the mortality rate was 4.3% (n = 13). Higher-than-normal NT-proBNP serum levels were found before surgery in 48.4% (n = 147) and after surgery in 50.7% (n = 154) of patients. The variables found to be independent predictors of cardiovascular complications, including all-cause 30-day mortality, were levels of NT-proBNP more than 300 pg ml before surgery and levels more than 1000 pg ml both before and after surgery.

CONCLUSION

High levels of preoperative and postoperative NT-proBNP are predictors of cardiovascular complications, including all-cause mortality, during the first 30 days after noncardiac surgery in adults with cardiovascular risk factors.

High-Sensitivity Cardiac Troponin T Improves the Diagnosis of Perioperative MI

BACKGROUND

The diagnosis of myocardial infarction (MI) after noncardiac surgery has traditionally relied on using relatively insensitive contemporary cardiac troponin (cTn) assays. We hypothesized that using a recently introduced novel high-sensitivity cTnT (hscTnT) assay would increase the detection rate of perioperative MI.

METHODS

In this ancillary study of the Vitamins in Nitrous Oxide trial, readjudicated incidence rates of myocardial injury (new isolated cTn elevation) and MI were compared when diagnosed by contemporary cTnI versus hscTnT. We probed various relative (eg, >50%) or absolute (eg, +5 ng/L) hscTnT change metrics. Inclusion criteria for this ancillary study were the presence of a baseline and at least 1 postoperative hscTnT value.

RESULTS

Among 605 patients, 70 patients (12%) had electrocardiogram changes consistent with myocardial ischemia; 82 patients (14%) had myocardial injury diagnosed by contemporary cTnI, 31 (5.1%) of which had an adjudicated MI. After readjudication, 67 patients (11%) were diagnosed with MI when using hscTnT, a 2-fold increase. Incidence rates of postoperative myocardial injury ranged from 12% (n = 73) to 65% (n = 393) depending on the hscTnT metric used. Incidence rates of MI using various hscTnT change metrics and the presence of ischemic electrocardiogram changes, but without event adjudication, ranged from 3.6% (n = 22) to 12% (n = 74), a >3-fold difference. New postoperative hscTnT elevation, either by absolute or relative hscTnT change metric, was associated with an up to 5-fold increase in 6-month mortality.

CONCLUSIONS

The use of hscTnT compared to contemporary cTnI increases the detection rate of perioperative MI by a factor of 2. Using different absolute or relative hscTnT change metrics may lead to under- or overdiagnosis of perioperative MI.

Improving Prediction of Postoperative Myocardial Infarction With High-Sensitivity Cardiac Troponin T and NT-proBNP

BACKGROUND

This study sought to determine whether preoperatively measured high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP) improve cardiac risk prediction in patients undergoing major noncardiac surgery compared with the standard risk indices.

METHODS

In this ancillary study to the Vitamins in Nitrous Oxide trial, patients were included who had preoperative hs-cTnT and NT-proBNP measured (n = 572). Study outcome was the incidence of postoperative myocardial infarction (MI) within the first 3 postoperative days. hs-cTnT was considered elevated if >14 ng/L and NT-proBNP if >300 ng/L. Additional cutoff values were investigated on the basis of receiver operating characteristic statistics. Biomarker risk prediction was compared with Lee's Revised Cardiac Risk Index (RCRI) with the use of standard methods and net reclassification index.

RESULTS

The addition of hs-cTnT (>14 ng/L) and NT-proBNP (>300 ng/L) to RCRI significantly improved the prediction of postoperative MI (event rate 30/572 [5.2%], Area under the receiver operating characteristic curve increased from 0.590 to 0.716 with a 0.66 net reclassification index [95% confidence interval 0.32-0.99], P < .001). The use of 108 ng/L as a cutoff for NT-proBNP improved sensitivity compared with 300 ng/L (0.87 vs 0.53). Sensitivity, specificity, positive, and negative predictive value for hs-cTnT were 0.70, 0.60, 0.09, and 0.97 and for NT-proBNP were 0.53, 0.68, 0.08, and 0.96.

CONCLUSIONS

The addition of cardiac biomarkers hs-cTnT and NT-proBNP to RCRI improves the prediction of adverse cardiac events in the immediate postoperative period after major noncardiac surgery. The high negative predictive value of preoperative hs-cTnT and NT-proBNP suggest usefulness as a "rule-out" test to confirm low risk of postoperative MI.

Isolated cardiac troponin rise does not modify the prognosis in elderly patients with hip fracture

Perioperative myocardial infarction remains a life-threatening complication in noncardiac surgery and even an isolated troponin rise (ITR) is associated with significant mortality. Our aim was to assess the prognostic value of ITR in elderly patients with hip fracture.In this cohort study, all patients admitted between 2009 and 2013 in our dedicated geriatric postoperative unit after hip fracture surgery with a cardiac troponin I determination were included and divided into Control, ITR, and acute coronary syndrome (ACS) groups. The primary end point was a composite criteria defined as 6-month mortality and/or re-hospitalization. Secondary end points included 30-day mortality, 6-month mortality, and 6-month functional outcome.Three hundred twelve patients were (age 85 ± 7 years) divided into Control (n = 217), ITR (n = 50), and ACS (n = 45) groups. There was no significant difference for any postoperative complications between ITR and Control groups. In contrast, atrial fibrillation, acute heart failure, hemorrhage, and ICU admission were significantly more frequent in the ACS group. Compared to the Control group, 6-month mortality and/or rehospitalization was not significantly modified in the ITR group (26% vs. 28%, P = 0.84, 95% confidence interval [CI] of the difference -13%-14%), whereas it was increased in the ACS group (44% vs. 28%, P = 0.02, 95% CI of the difference 2%-32%). ITR was not associated with a higher risk of new institutionalization or impaired walking ability at 6 months, in contrast to ACS group.In elderly patients with hip fracture, ITR was not associated with a significant increase in death and/or rehospitalization within 6 months.

Myocardial injury in patients with hemodynamic derangements during and/or after liver transplantation

Myocardial injury, defined as an elevation of cardiac troponin (cTn) resulting from ischemia, is associated with substantial mortality in surgical patients, and its incidence, risk factors, and impact on patients undergoing liver transplantation (LT) are poorly understood. In this study, adult patients who experienced perioperative hemodynamic derangements and had cTn measurements within 30 days after LT between 2006 and 2013 were studied. Of 502 patients, 203 (40.4%) met the diagnostic criteria (cTn I ≥0.1 ng/mL) of myocardial injury. The majority of myocardial injury occurred within the first three postoperative days and presented without clinical signs or symptoms of myocardial infarction. Thirty-day mortality in patients with myocardial injury was 11.4%, significantly higher compared with that in patients without myocardial injury (3.4%, P<.01). Cox analysis indicated the peak cTn was significantly associated with 30-day mortality. Multivariable logistic analysis identified three independent risk factors: requirement of ventilation before transplant (odds ratios (OR) 1.6, P=.006), RBC≥15 units (OR 1.7, P=.006), and the presence of PRS (OR 2.0, P=.028). We concluded that post-LT myocardial injury in this high-risk population was common and associated with mortality. Our findings may be used in pretransplant stratification. Further studies to investigate this postoperative cardiac complication in all LT patients are warranted.

[Perioperative risk and mortality after major surgery]

Although anesthesia-associated mortality has been significantly reduced down to 0.00068-0.00082% over the last decades, recent studies have revealed a high perioperative mortality of 0.8- 4%. Apart from anesthesia and surgery-induced major complications, perioperative mortality is primarily negatively influenced by individual patient comorbidities. These risk factors predispose for acute critical incidents (e.g., myocardial infarction); however, the majority of fatal complications are a result of slowly progressing conditions, particularly infections or the sequelae of systemic inflammation. This implicates a broad window of opportunity for the detection and treatment of slow-onset complications to improve the perioperative outcome. The term "failure to rescue" (FTR), i.e., the proportion of patients who die from major complications compared to the number of all patients with complications, has been introduced as a valid indicator for the quality of perioperative care. Growing evidence has already shown that FTR is an underestimated factor in perioperative medicine accounting for or at least being involved in the development of postoperative mortality. While the incidence of severe postoperative complications amazingly does not show much variation between hospitals, FTR shows significant differences implying a major potential for improvement. With 14 million surgical procedures per year in Germany, a postoperative mortality of approximately 1% and an avoidable FTR rate of 40% mean that there are an estimated 60,000 preventable deaths per year. Hence, in the future it will be imperative to (1) identify patients at risk, (2) to prevent the development of postoperative complications with the use of adequate adjunctive therapeutic strategies, (3) to establish surveillance and monitoring systems for the early detection of postoperative complications and (4) to treat postoperative complications efficiently and in time when they arise.

Postoperative management

Most patients undergoing major aortic surgery have multiple comorbidities and are at high risk of postoperative complications that affect multiple organ systems. Different aortic pathologies and surgical repair techniques have specific impact on the postoperative course. Ischemia-reperfusion injury is the common denominator in aortic surgery and influences the integrity of end-organ function. Common postoperative problems include hemodynamic instability due to the immediate inflammatory response, renal impairment, spinal cord ischemia, respiratory failure with prolonged mechanical ventilation, and gastrointestinal symptoms such as ileus or mesenteric ischemia. Focused care bundles to establish homeostasis and a team working toward an early functional recovery determine the success of effective rehabilitation and outcomes after aortic surgery.

Preoperative Laboratory Testing

Routine preoperative testing is not cost-effective, because it is unlikely to identify significant abnormalities. Abnormal findings from routine testing are more likely to be false positive, are costly to pursue, introduce a new risk, increase the patient's anxiety, and are inconvenient to the patient. Abnormal findings rarely alter the surgical or anesthetic plan, and there is usually no association between perioperative complications and abnormal laboratory results. Incidental findings and false positive results may lead to increased hospital visits and admissions. Preoperative testing needs to be done based on a targeted history and physical examination and the type of surgery.

Proposed research plan for the derivation of a new Cardiac Risk Index

The Revised Cardiac Risk Index (RCRI) was incorporated into the American College of Cardiology/American Heart Association (ACC/AHA) recommendations for the preoperative evaluation of the cardiac patient for noncardiac surgery. The purpose of this review was to analyze studies on cardiovascular clinical risk prediction that had used the previous "standard best" model, the RCRI, as a comparator. This review aims to determine whether modification of the current risk factors or adoption of other risk factors or other risk indices would improve upon the discrimination of cardiac risk prediction when compared with the RCRI. This is necessary because recent risk prediction models have shown better discrimination for major adverse cardiac events, and the pre-eminence of the RCRI is now in question. There is now a need for a new "best standard" cardiovascular risk prediction model to supersede the RCRI. This is desirable because it would: (1) allow for a global standard of cardiovascular risk assessment; (2) provide a standard comparator in all risk prediction research; (3) result in comparable data collection; and (4) allow for individual patient data meta-analyses. This should lead to continued progress in cardiovascular clinical risk prediction. A review of the current evidence suggests that to improve the preoperative clinical risk stratification for adverse cardiac events, a new risk stratification model be built that maintains the clinical risk factors identified in the RCRI, with the following modifications: (1) additional glomerular filtration rate cut points (as opposed to a single creatinine cut point); (2) age; (3) a history of peripheral vascular disease; (4) functional capacity; and (5) a specific surgical procedural category. One would expect a substantial improvement in the discrimination of the RCRI with this approach. Although most noncardiac surgeries will benefit from a standard "generic" cardiovascular risk prediction model, there are data to suggest that patients with human immunodeficiency virus disease who are undergoing vascular surgery may benefit from specific cardiovascular risk prediction models.