The prognostic value of pre-operative and post-operative B-type natriuretic peptides in patients undergoing noncardiac surgery: B-type natriuretic peptide and N-terminal fragment of pro-B-type natriuretic peptide: a systematic review and individual patient data meta-analysis

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.

Cardiac Biomarkers Predict 1-Year Mortality in Elderly Patients Undergoing Hip Fracture Surgery

This prospective study included 152 elderly patients (mean age, 80 years; range, 72-88 years) with a hip fracture treated surgically. Comorbidities were evaluated, and B-type natriuretic peptide was measured at baseline and at postoperative days 4 and 5 in addition to troponin I. Major cardiac events were recorded, and 1-year mortality was assessed. Comorbidity models with the important multivariate predictors of 1-year mortality were analyzed. Overall, 9 patients (6%) experienced major cardiac events postoperatively during their hospitalization. Three patients (2%) died postoperatively, at days 5, 7, and 10, from autopsy-confirmed myocardial infarction. Three patients (2%) experienced a nonfatal myocardial infarction, and 3 patients (2%) experienced acute heart failure. At 1-year follow-up, 37 patients (24%) had died. Age older than 80 years (P=.000), renal failure (P=.016), cardiovascular disease (P=.003), respiratory disease (P=.010), Parkinson disease (P=.024), and dementia (P=.000) were univariate predictors of 1-year mortality. However, in the multivariate model, only age older than 80 years (P=.000) and dementia (P=.024) were important predictors of 1-year mortality. In all comorbidity models, age older than 80 years and dementia were important predictors of 1-year mortality. Postoperative increase in B-type natriuretic peptide was the most important predictor of 1-year mortality. Receiver operating characteristic curve analysis showed a threshold of 90 ng/mL of preoperative B-type natriuretic peptide (area under the curve=0.773, 95% confidence interval, 0.691-0.855, P<.001) had 82% sensitivity and 62% specificity to predict 1-year mortality. Similarly, a threshold of 190 ng/mL of postoperative B-type natriuretic peptide (area under the curve=0.753, 95% confidence interval, 0.662-0.844, P<.001) had 70% sensitivity and 77% specificity to predict the study endpoint. [Orthopedics. 2017; 40(3):e417-e424.].

Presepsin (sCD14-ST) Is a Novel Marker for Risk Stratification in Cardiac Surgery Patients

Background

Presepsin (soluble cluster-of-differentiation 14 subtype [sCD14-ST]) is a humoral risk stratification marker for systemic inflammatory response syndrome and sepsis. It remains unknown whether presepsin can be used to stratify risk in elective cardiac surgery. The authors therefore determined the usefulness of presepsin for risk stratification in patients having elective cardiac surgery.

Methods

Eight hundred fifty-six cardiac surgical patients were prospectively studied. Preoperative plasma concentrations of presepsin, procalcitonin, N-terminal pro–hormone natriuretic peptide, cystatin C, and the additive European System of Cardiac Operative Risk Evaluation 2 were compared to mortality at 30 days (primary outcome), 6 months, and 2 yr. Discrimination was assessed with C statistic. Logistic regression analysis was used to calculate univariable and multivariable odds ratios.

Results

Thirty-day mortality was 3.2%, 6-month mortality was 6.1%, and 2-yr mortality was 10.4% across the population. Median preoperative presepsin concentrations were significantly greater in 30-day nonsurvivors than in survivors: 842 pg/ml (interquartile range, 306 to 1,246) versus 160 pg/ml (interquartile range, 122 to 234); difference, 167 pg/ml (interquartile range, 92 to 301; P &lt; 0.001). The results were similar for 6-month and 2-yr mortality. Compared to the European System of Cardiac Operative Risk Evaluation 2, presepsin concentration provided better discrimination for postoperative mortality at all follow-up periods, including 30 days (C statistic 0.88 vs. 0.74), 6 months (0.87 vs. 0.76), and 2 yr (0.81 vs. 0.74). Presepsin also provided better discrimination than cystatin C, N-terminal pro–hormone natriuretic peptide, or procalcitonin. Elevated presepsin remained an independent risk predictor after adjustment for potential confounding factors.

Conclusions

Elevated preoperative plasma presepsin concentration is an independent predictor of postoperative mortality in elective cardiac surgery patients and is a stronger predictor than several other commonly used assessments.

Adrenomedullin Is Associated With Surgical Trauma and Impaired Renal Function in Vascular Surgery Patients

BACKGROUND:

Patients undergoing vascular surgery are prone to perioperative organ injury because of both higher prevalence of cardiovascular risk factors and the extent of surgery. Early detection of organ failure is essential to facilitate appropriate medical care. Midregional pro-adrenomedullin (MR-proADM) has been investigated in acute medical care settings to guide clinical decision-making regarding patient pathways and to identify patients prone to imminent cardiovascular or inflammatory complications. In this study, we evaluated the impact of perioperative MR-proADM levels as an early marker of perioperative cardiovascular and inflammatory stress reactions and kidney injury.

METHODS:

The study was conducted as a monocentric, prospective, noninterventional trial at Hannover Medical School, Germany. A total of 454 consecutive patients who underwent open vascular surgery were followed from the day prior to until 30 days after surgery. The composite primary end point was defined as the occurrence of major adverse cardiac events (MACEs), acute kidney injury (AKI), or systemic inflammatory response syndrome (SIRS). Measurements were correlated with both medical history and postoperative MACE, AKI, or SIRS using univariate and multivariate regression analysis.

RESULTS:

One hundred thirty-nine (31%) of the patients reached the primary end point within the study interval. Midregional pro-adrenomedullin change was associated with the combined primary end point and with the intensity of surgical trauma. Midregional pro-adrenomedullin change was increased in patients reaching the secondary end points, SIRS (optimal cutoff: 0.2 nmol/L) and AKI (optimal cutoff: 0.7 nmol/L), but not in patients with MACEs.

CONCLUSION:

Increased levels of MR-proADM within the perioperative setting (1) were linked to the invasiveness of surgery and (2) identified patients with ongoing loss of renal function. Increased MR-proADM levels may therefore identify a subgroup of patients prone to excessive cardiovascular stress but did not directly correlate with adverse cardiac events. Consistently low levels of MR-proADM may identify a subgroup of patients with acceptable low risk to guide discharge from high-density care units.

External validation of the Revised Cardiac Risk Index and update of its renal variable to predict 30-day risk of major cardiac complications after non-cardiac surgery: rationale and plan for analyses of the VISION study

INTRODUCTION

The Revised Cardiac Risk Index (RCRI) is a popular classification system to estimate patients' risk of postoperative cardiac complications based on preoperative risk factors. Renal impairment, defined as serum creatinine >2.0 mg/dL (177 µmol/L), is a component of the RCRI. The estimated glomerular filtration rate has become accepted as a more accurate indicator of renal function. We will externally validate the RCRI in a modern cohort of patients undergoing non-cardiac surgery and update its renal component.

METHODS AND ANALYSIS

The Vascular Events in Non-cardiac Surgery Patients Cohort Evaluation (VISION) study is an international prospective cohort study. In this prespecified secondary analysis of VISION, we will test the risk estimation performance of the RCRI in ∼34 000 participants who underwent elective non-cardiac surgery between 2007 and 2013 from 29 hospitals in 15 countries. Using data from the first 20 000 eligible participants (the derivation set), we will derive an optimal threshold for dichotomising preoperative renal function quantified using the Chronic Kidney Disease Epidemiology Collaboration (CKD-Epi) glomerular filtration rate estimating equation in a manner that preserves the original structure of the RCRI. We will also develop a continuous risk estimating equation integrating age and CKD-Epi with existing RCRI risk factors. In the remaining (approximately) 14 000 participants, we will compare the risk estimation for cardiac complications of the original RCRI to this modified version. Cardiac complications will include 30-day non-fatal myocardial infarction, non-fatal cardiac arrest and death due to cardiac causes. We have examined an early sample to estimate the number of events and the distribution of predictors and missing data, but have not seen the validation data at the time of writing.

ETHICS AND DISSEMINATION

The research ethics board at each site approved the VISION protocol prior to recruitment. We will publish our results and make our models available online at http://www.perioperativerisk.com.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT00512109.

Sleep apnea in total joint arthroplasty patients and the role for cardiac biomarkers for risk stratification: an exploration of feasibility

Obstructive sleep apnea (OSA) is highly prevalent in patients undergoing total joint arthroplasty (TJA) and is a major risk factor for postoperative cardiovascular complications and death. Recognizing this, the American Society of Anesthesiologists urges clinicians to implement special considerations in the perioperative care of OSA patients. However, as the volume of patients presenting for TJA increases, resources to implement these recommendations are limited. This necessitates mechanisms to efficiently risk stratify patients having OSA who may be susceptible to post-TJA cardiovascular complications. We explore the role of perioperative measurement of cardiac troponins (cTns) and brain natriuretic peptides (BNPs) in helping determine which OSA patients are at increased risk for post-TJA cardiovascular-related morbidity.

B-type Natriuretic Peptide Predicts Morbidity and Long-Term Mortality in Coronary Artery Bypass Grafting and Valve Surgery

OBJECTIVE

To assess whether B-type natriuretic peptide (BNP) levels are a useful predictor of morbidity and mortality as well as long-term survival in patients after coronary artery bypass grafting (CABG) and valve surgery.

METHODS

A retrospective review of CABG and/or valve surgery patients from 2012 to 2015 at a single center was conducted. A total of 432 patients were identified (CABG, 295 patients; valve, 82 patients; and CABG + valve, 55 patients). B-type natriuretic peptide levels were divided into quartiles (Q1-Q4). Mortality data were available for up to 3.4 years after surgery.

RESULTS

B-type natriuretic peptide quartile was independently associated with any complication on multivariate analysis. Patients in Q4 were at highest risk (adjusted odds ratio, 3.81; P = 0.047 vs Q1). There was a significant association between BNP quartile and time to death (log-rank χ, 8.30; P = 0.04) with greatest association 9 months postoperatively. B-type natriuretic peptide quartile was significantly associated with time to death in Cox regression in Q2 (hazard ratio [HR], 3.73 (1.04-13.44); P = 0.044) and Q4 (HR, 4.33 (1.14-16.44); P = 0.031). Q3 also had a higher risk of death (HR, 3.5 vs Q1); however, this was only significant at a trend level (P = 0.06). Using a risk model generated from logistic regression, we determined that the highest risk group had relative risk of complications 30 times higher than the lowest risk group.

CONCLUSIONS

B-type natriuretic peptide levels are an independent predictor of morbidity after CABG and/or valve surgery regardless of type of procedure or on/off bypass usage. B-type natriuretic peptide levels also correlate with time to death, highlighting the need for sustained follow-up and heart failure management to improve survival in patients with elevated BNP levels presenting for all cardiac surgery.

Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery

The Canadian Cardiovascular Society Guidelines Committee and key Canadian opinion leaders believed there was a need for up to date guidelines that used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system of evidence assessment for patients who undergo noncardiac surgery. Strong recommendations included: 1) measuring brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) before surgery to enhance perioperative cardiac risk estimation in patients who are 65 years of age or older, are 45-64 years of age with significant cardiovascular disease, or have a Revised Cardiac Risk Index score ≥ 1; 2) against performing preoperative resting echocardiography, coronary computed tomography angiography, exercise or cardiopulmonary exercise testing, or pharmacological stress echocardiography or radionuclide imaging to enhance perioperative cardiac risk estimation; 3) against the initiation or continuation of acetylsalicylic acid for the prevention of perioperative cardiac events, except in patients with a recent coronary artery stent or who will undergo carotid endarterectomy; 4) against α₂ agonist or β-blocker initiation within 24 hours before surgery; 5) withholding angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker starting 24 hours before surgery; 6) facilitating smoking cessation before surgery; 7) measuring daily troponin for 48 to 72 hours after surgery in patients with an elevated NT-proBNP/BNP measurement before surgery or if there is no NT-proBNP/BNP measurement before surgery, in those who have a Revised Cardiac Risk Index score ≥1, age 45-64 years with significant cardiovascular disease, or age 65 years or older; and 8) initiating of long-term acetylsalicylic acid and statin therapy in patients who suffer myocardial injury/infarction after surgery.

The Impact of Biochemical Markers on Major Adverse Cardiovascular Events and Contralateral Carotid Artery Stenosis Progression Following Carotid Interventions

BACKGROUD

To determine if elevated preintervention high-sensitivity C-reactive protein (hsCRP) and B-type natriuretic peptide (BNP) levels associate with major adverse cardiovascular events (MACE) or disease progression after carotid revascularization.

METHODS

We retrospectively examined patients receiving elective carotid endarterectomy (CEA) or carotid artery stenting (CAS) at our institution from 2007 to 2014. All included patients had preintervention hsCRP and BNP levels. Examined outcomes of interest included contralateral carotid disease progression (increased stenosis or need for revascularization) and MACE (composite of death, stroke, myocardial infarction, need for coronary artery bypass graft or percutaneous coronary intervention) at 3 years after procedure. The relationship between baseline hsCRP and BNP levels and time to event was examined by univariate and multivariate Cox proportional hazard regression analyses.

RESULTS

A total of 248 patients were included in the analysis (mean age: 68 ± 10 years), with 14% receiving CAS and 86% CEA. A total of 61 patients (25%) had 1 or more MACE by 3 years. Elevated hsCRP (>3 mg/L) trended toward associating with MACE but failed to reach significance (hazard ratio [HR]: 1.6 [1.0-2.7], P = 0.07). Multivariate analysis found that elevated BNP (>100pg/mL, HR: 2.2 [1.3-3.7], P = 0.002) and diabetes mellitus (HR: 1.9 [1.2-3.2], P = 0.01) predicted MACE. Having elevated preprocedural levels of both hsCRP and BNP significantly increased patients' likelihood of experiencing MACE (HR: 3.4 [1.6-7.1], P = 0.001). About 175 patients received contralateral carotid imaging postprocedure and of those patients, 31 (18%) experienced stenosis progression and/or revascularization within 3 years. However, neither elevated hsCRP (HR: 1.2 [0.6-2.3], P = 0.68) nor BNP (HR: 1.1 [0.5-2.5], P = 0.88) associated with disease progression.

CONCLUSIONS

BNP elevation at the time of carotid intervention is associated with MACE in long-term follow-up. hsCRP does not appear to correlate with either disease progression of the contralateral artery or MACE.

Biomarkers in Pediatric Cardiac Critical Care

OBJECTIVES

In this review, we discuss the physiology, pathophysiology, and clinical role of troponin, lactate, and B-type natriuretic peptide in the assessment and management of children with critical cardiac disease.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSION

Lactate, troponin, and B-type natriuretic peptide continue to be valuable biomarkers in the assessment and management of critically ill children with cardiac disease. However, the use of these markers as a single measurement is handicapped by the wide variety of clinical scenarios in which they may be increased. The overall trend may be more useful than any single level with a persistent or rising value of more importance than an elevated initial value.

Biochemical markers in patients with open reconstructions with peripheral arterial disease

The purpose of our study was to determine outcome differences as a function of baseline high-sensitivity C-reactive protein (hsCRP) and B-type natriuretic peptide (BNP) levels in patients receiving lower extremity open reconstructions for the treatment of peripheral arterial occlusive disease. We retrospectively examined patients who underwent surgical reconstructions performed by a single operator during a seven-year time span who received preoperative hsCRP and BNP testing and post-procedure imaging. Outcomes of interest included major adverse limb events, a composite end point of target vessel revascularization, limb amputation, and disease progression, and major adverse cardiovascular events comprised of stroke, myocardial infarction, and death. A total of 89 limbs in 82 patients were included in analysis. Multivariate analysis demonstrated that higher hsCRP levels (>3.0 mg/L) trended toward, but failed to significantly associate with major adverse limb events at 24 months (hazard ratio: 2.2 [1.0–5.2], p = 0.06), however the use of a vein bypass conduit (vs. prosthetic reconstruction) significantly predicted major adverse limb events (hazard ratio: 3.2 [1.5–6.9], p < 0.01). Elevated BNP levels (>100 pg/ml), but not hsCRP, associated with major adverse cardiovascular events (hazard ratio: 3.5 [1.2–10.3], p = 0.03). Preoperative biochemical markers may assist in clinical decision making and stratifying patients regarding adverse events following open reconstructions.

N-terminal pro B type natriuretic peptide in high cardiovascular-risk patients for noncardiac surgery: What is the current prognostic evidence?

As millions of surgical procedures are performed worldwide on an aging population with multiple comorbidities, accurate and simple perioperative risk stratification is critical. The cardiac biomarker, brain natriuretic peptide (BNP), has generated considerable interest as it is easy to obtain and appears to have powerful predictive and prognostic capabilities. BNP is currently being used to guide medical therapy for heart failure and has been added to several algorithms for perioperative risk stratification. This review examines the current evidence for the use of BNP in the perioperative period in patients who are at high-cardiovascular risk for noncardiac surgery. In addition, we examined the use of BNP in patients with pulmonary embolism and left ventricular assist devices. The available data strongly suggest that the addition of BNP to perioperative risk calculators is beneficial; however, whether this determination of risk will impact outcomes, remains to be seen.

Measurement of Exercise Tolerance before Surgery (METS) study: a protocol for an international multicentre prospective cohort study of cardiopulmonary exercise testing prior to major non-cardiac surgery

INTRODUCTION

Preoperative functional capacity is considered an important risk factor for cardiovascular and other complications of major non-cardiac surgery. Nonetheless, the usual approach for estimating preoperative functional capacity, namely doctors' subjective assessment, may not accurately predict postoperative morbidity or mortality. 3 possible alternatives are cardiopulmonary exercise testing; the Duke Activity Status Index, a standardised questionnaire for estimating functional capacity; and the serum concentration of N-terminal pro-B-type natriuretic peptide (NT pro-BNP), a biomarker for heart failure and cardiac ischaemia.

METHODS AND ANALYSIS

The Measurement of Exercise Tolerance before Surgery (METS) Study is a multicentre prospective cohort study of patients undergoing major elective non-cardiac surgery at 25 participating study sites in Australia, Canada, New Zealand and the UK. We aim to recruit 1723 participants. Prior to surgery, participants undergo symptom-limited cardiopulmonary exercise testing on a cycle ergometer, complete the Duke Activity Status Index questionnaire, undergo blood sampling to measure serum NT pro-BNP concentration and have their functional capacity subjectively assessed by their responsible doctors. Participants are followed for 1 year after surgery to assess vital status, postoperative complications and general health utilities. The primary outcome is all-cause death or non-fatal myocardial infarction within 30 days after surgery, and the secondary outcome is all-cause death within 1 year after surgery. Both receiver-operating-characteristic curve methods and risk reclassification table methods will be used to compare the prognostic accuracy of preoperative subjective assessment, peak oxygen consumption during cardiopulmonary exercise testing, Duke Activity Status Index scores and serum NT pro-BNP concentration.

ETHICS AND DISSEMINATION

The METS Study has received research ethics board approval at all sites. Participant recruitment began in March 2013, and 1-year follow-up is expected to finish in 2016. Publication of the results of the METS Study is anticipated to occur in 2017.

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.

How can we identify the high-risk patient?

Purpose of review

Accurate and early identification of high-risk surgical patients allows for targeted use of perioperative monitoring and interventions that may improve their outcomes. This review summarizes current evidence on how information from the preoperative, operative, and immediate postoperative periods can help identify such individuals.

Recent findings

Simple risk indices, such as the Revised Cardiac Risk Index or American Society of Anesthesiologists Physical Status scale, and online calculators allow risk to be estimated with moderate accuracy using readily available preoperative clinical information. Both specific specialized tests (i.e., cardiopulmonary exercise testing and cardiac stress testing) and promising novel biomarkers (i.e., troponins and natriuretic peptides) can help refine these risk estimates before surgery. Estimates of perioperative risk can be further informed by information acquired during the operative and immediate postoperative periods, such as risk indices (i.e., surgical Apgar score), individual risk factors (i.e., intraoperative hypotension), or postoperative biomarkers (i.e., troponins and natriuretic peptides).

Summary

Preoperative clinical risk indices and risk calculators estimate surgical risk with moderate accuracy. Although novel biomarkers, specialized preoperative testing, and immediate postoperative risk indices show promise as methods to refine these risk estimates, more research is needed on how best to integrate risk information from these different sources.

Predicting outcomes: Is there utility in risk scores?

PURPOSE

This review discusses the utility of risk scores, specifically, the role of preoperative risk scores in guiding the management of surgical patients, approaches to evaluate the quality of risk scores, and limitations to consider when applying risk scores in clinical practice.

PRINCIPAL FINDINGS

This review shows how accurate predictions of perioperative risk can help inform patients and clinicians with respect to decision-making around surgery; identify patients who warrant further specialized investigations, new interventions intended to decrease risk, modifications in planned operative procedures, or intensification of postoperative monitoring; and facilitate fairer comparisons of outcomes between providers and hospitals. A preoperative risk score formally integrates several pieces of clinical information (e.g., age, comorbid disease, laboratory tests) to arrive at an overall estimate of an individual patient's expected risk for specific postoperative adverse events. A good risk score should be simple to incorporate in clinical practice, reliable when applied by different raters, and accurate at predicting postoperative risk. Several analytical methods (e.g., receiver operating characteristic curves, likelihood ratios, risk reclassification tables, observed vs predicted plots) are required to characterize the relevant domains that encompass the prognostic accuracy of a risk score. External validation is critical in determining whether the predictive accuracy of a risk score is preserved when applied to new settings, populations, or outcome events.

CONCLUSIONS

Preoperative risk scores help inform perioperative clinical decision-making. Future research must determine how estimates of preoperative risk can be updated with information from the intraoperative period, how risk information should be communicated to patients, and which interventions can improve outcomes among patients within newly identified risk strata.

Pre-operative pulmonary evaluation in the patient with suspected respiratory disease

Post-operative pulmonary complications (POPC) occur frequently, especially in patients with pre-existing pulmonary disease and have a significant effect on post-surgical morbidity and mortality. By understanding the patient's existing pulmonary diseases that have a significant effect on post-operative morbidities a combination of information has to be gathered from a thorough history and physical exam as well as selected laboratory and diagnostic tests. Evidence based scores can then be employed to predict the risk of significant POPC. Numbers and testing alone, however, such as diagnosis of chronic obstructive pulmonary disease based on spirometry, may not provide as clear a picture as of the true risk of POPC that is determined by a combination of estimations of the patient's functional status, (b) measured by the patient's estimates of activity and (c) confirmed by the patient's ability to perform simple tasks such as the 6-minute walk test. This information can then be used to rationalize perioperative interventions and improve the safety of the perioperative experience.

N-terminal pro-B-type Natriuretic Peptides’ Prognostic Utility Is Overestimated in Meta-analyses Using Study-specific Optimal Diagnostic Thresholds

Background:

N-terminal fragment B-type natriuretic peptide (NT-proBNP) prognostic utility is commonly determined post hoc by identifying a single optimal discrimination threshold tailored to the individual study population. The authors aimed to determine how using these study-specific post hoc thresholds impacts meta-analysis results.

Methods:

The authors conducted a systematic review of studies reporting the ability of preoperative NT-proBNP measurements to predict the composite outcome of all-cause mortality and nonfatal myocardial infarction at 30 days after noncardiac surgery. Individual patient-level data NT-proBNP thresholds were determined using two different methodologies. First, a single combined NT-proBNP threshold was determined for the entire cohort of patients, and a meta-analysis conducted using this single threshold. Second, study-specific thresholds were determined for each individual study, with meta-analysis being conducted using these study-specific thresholds.

Results:

The authors obtained individual patient data from 14 studies (n = 2,196). Using a single NT-proBNP cohort threshold, the odds ratio (OR) associated with an increased NT-proBNP measurement was 3.43 (95% CI, 2.08 to 5.64). Using individual study-specific thresholds, the OR associated with an increased NT-proBNP measurement was 6.45 (95% CI, 3.98 to 10.46). In smaller studies (&lt;100 patients) a single cohort threshold was associated with an OR of 5.4 (95% CI, 2.27 to 12.84) as compared with an OR of 14.38 (95% CI, 6.08 to 34.01) for study-specific thresholds.

Conclusions:

Post hoc identification of study-specific prognostic biomarker thresholds artificially maximizes biomarker predictive power, resulting in an amplification or overestimation during meta-analysis of these results. This effect is accentuated in small studies.

B-type natriuretic peptide following thoracic surgery: a predictor of postoperative cardiopulmonary complications

OBJECTIVES

B-type natriuretic peptides (BNPs) are secreted by the human heart in response to ventricular wall stretch or myocardial ischaemia, and predict adverse cardiovascular events and death in the general population. Following non-cardiac surgical procedures, there is growing evidence supporting BNP measurement as a powerful independent predictor of death and perioperative complications. However, the clinical implication of elevated BNP measurements after pulmonary resection has not been completely defined. This study aimed to evaluate the role of BNP in predicting adverse cardiopulmonary events after thoracic surgery.

METHODS

A prospective, short-term, observational cohort study was conducted in a tertiary care hospital, including consecutive patients undergoing scheduled pulmonary resection between April 2012 and October 2013. Baseline clinical details were obtained; serum BNP levels were measured at baseline and on postoperative days 1 and 4.

RESULTS

We enrolled 294 consecutive patients, median age 66 [interquartile range (IQR): 57-73], 67% male. There were 2 perioperative deaths, and 52 patients experienced one or more cardiopulmonary complications. The baseline median BNP value was normal (29.5 pg/ml, IQR: 16-57.2), and showed significant postoperative increase, peaking on day 1. Patients who developed postoperative complications had a significantly greater BNP increase (P < 0.0001) when compared with those without complications. A postoperative day 1 BNP measurement of ≥118.5 [receiver operating characteristic area: 0.654; 95% confidence interval (CI): 0.57-0.74; P = 0.001] was associated with a 3-fold risk of developing postoperative cardiopulmonary complications [odds ratio (OR): 2.94; 95% CI: 1.32-6.57; P = 0.008]. Logistic regression analysis showed major pulmonary resections (lobectomies or pneumonectomies), BNP ≥ 118.5 and age ≥ 65 to be the only independent predictive variables. In the subset of patients undergoing lobectomy or pneumonectomy (n = 226), BNP was the strongest independent predictor of complications (OR: 3.49; 95% CI: 1.51-8.04).

CONCLUSIONS

Our results show that BNP elevation, measured in the first days after thoracic surgery, is independently associated with postoperative adverse events. In patients undergoing major pulmonary resections, a postoperative BNP elevation is the strongest independent predictor of cardiopulmonary complications.

Low baseline proBNP associated with increased risk of intraoperative hypotension during spinal anaesthesia for cesarean delivery

BACKGROUND AND OBJECTIVES

Brain natriuretic peptide (BNP) has a role in the regulation of body fluid volume and blood pressure (BP). BNP remains within a normal range during spinal anaesthesia (SA) in patients undergoing cesarean delivery. However, the effect of BNP on changes in BP during the perioperative period has not been evaluated. We aimed to investigate the effect of preoperative serum BNP on the risk of hypotension during cesarean delivery with SA.

DESIGN AND SETTINGS

Patients were randomly selected among the patient group who were attending routine clinic visits for pregnancy monitoring. All had a healthy pregnancy and no other acute or chronic disease by their obstetrician. The study design was cross-sectional.

PATIENTS AND METHODS

Patients who had uncomplicated pregnancy process and no known medical dis.ease were selected consecutively during their last outpatient clinical examination. Baseline BP was recorded before SA. Simultaneously, blood samples were drawn for routine biochemistry and BNP. BP, SaO2, and electrocardiography were monitored during surgery. Intraoperative hypotension (IOH) was defined as >=25% decrease in mean arterial pressure (MAP) at the 5th minute of SA.

RESULTS

In 41 term pregnant women, 18 of the 41 patients (43.9%) fulfilled the criteria for IOH, while 23 (56.1%) showed a decrease 13.1 (11.3%) and were classified as normotensive. Baseline BNP was significantly lower in patients with IOH compared with normotensive patients 45.7 (26.9) vs.70.2 (40.5); P=.05. Baseline BNP had no significant correlation MAP at any time point. Age, body mass index, hemoglobin, baseline MAP and heart rate were not different between patients with and without IOH.

CONCLUSION

Those findings suggest that higher baseline BNP levels might have a protective role in development of hypotension in healthy term pregnant women during SA for cesarean delivery.

Prognostic capabilities of coronary computed tomographic angiography before non-cardiac surgery: prospective cohort study

OBJECTIVES

To determine if coronary computed tomographic angiography enhances prediction of perioperative risk in patients before non-cardiac surgery and to assess the preoperative coronary anatomy in patients who experience a myocardial infarction after non-cardiac surgery.

DESIGN

Prospective cohort study.

SETTING

12 centers in eight countries.

PARTICIPANTS

955 patients with, or at risk of, atherosclerotic disease who underwent non-cardiac surgery.

INTERVENTIONS

Coronary computed tomographic angiography was performed preoperatively; clinicians were blinded to the results unless left main disease was suspected. Results were classified as normal, non-obstructive (<50% stenosis), obstructive (one or two vessels with ≥ 50% stenosis), or extensive obstructive (≥ 50% stenosis in two vessels including the proximal left anterior descending artery, three vessels, or left main).

MAIN OUTCOME MEASURE

Composite of cardiovascular death and non-fatal myocardial infarction within 30 days after surgery (primary outcome). This was the dependent variable in Cox regression. The independent variables were scores on the revised cardiac risk index and findings on coronary computed tomographic angiography.

RESULTS

The primary outcome occurred in 74 patients (8%). The model that included both scores on the revised cardiac risk index and findings on coronary computed tomographic angiography showed that coronary computed tomographic angiography provided independent prognostic information (P=0.014; C index=0.66). The adjusted hazard ratios were 1.51 (95% confidence interval 0.45 to 5.10) for non-obstructive disease; 2.05 (0.62 to 6.74) for obstructive disease; and 3.76 (1.12 to 12.62) for extensive obstructive disease. For the model with coronary computed tomographic angiography compared with the model based on the revised cardiac risk index alone, with 30 day risk categories of <5%, 5-15%, and >15% for the primary outcome, the results of risk reclassification indicate that in a sample of 1000 patients that coronary computed tomographic angiography would have resulted appropriately in 17 net patients receiving a higher risk estimation among the 77 patients who would have experienced the primary outcome (P<0.001). Coronary computed tomographic angiography, however, would have resulted inappropriately in 98 net patients receiving a higher risk estimation, among the 923 patients who would not have experienced the primary outcome (P<0.001). Among patients who had a perioperative myocardial infarction, preoperative coronary anatomy showed extensive obstructive disease in 31% (22/71), obstructive disease in 41% (29/71), non-obstructive disease in 24% (17/71), and normal findings in 4% (3/71).

CONCLUSIONS

Though findings on coronary computed tomographic angiography can improve estimation of risk for patients who will experience perioperative cardiovascular death or myocardial infarction, findings are more than five times as likely to lead to an inappropriate overestimation of risk among patients who will not experience these outcomes. Perioperative myocardial infarction occurs across the spectrum of coronary artery disease, suggesting that there could be several pathophysiologic mechanisms.

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.

Cardiac biomarkers and risk assessment in patients undergoing major non-cardiac surgery: time to revise the guidelines?

Although the perioperative event rate has declined over the past 30 years, as a consequence of the developments in anesthesiology and surgical techniques, perioperative cardiovascular complications are still a significant clinical problem. At the end of the last century, a pooled analysis of several large studies found a 30-day incidence of cardiac events of 2.5% in unselected patients aged >40 years. The identification of myocardial injury after non-cardiac surgery is a problematic and tough challenge, since up to 50% of cardiac deaths actually occur in patients with no history of overt heart disease. Recently, among novel sensitive and specific cardiovascular risk markers, the European Society of Cardiology and European Society of Anesthesiology guidelines for preoperative cardiac risk assessment have recommended that preoperative brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) measurement should be considered in high-risk patients undergoing non-cardiac surgery. However, several recent studies and meta-analyses, published in the last 5 years, strongly support the use of both assays of cardiac B-type natriuretic peptides and troponins, for risk stratification in patients undergoing non-cardiac surgery, in order to improve operative and postoperative outcome. Indeed, an increase in specific cardiac biomarkers, as it is the case for natriuretic peptides and troponins, always indicates that the heart is under a stress condition or even actually injured, respectively. In conclusion, the authors suggest that future guidelines on cardiovascular risk evaluation in patients undergoing major surgical procedures should take into account the following evidence.

Cirrhotic cardiomyopathy: Implications for the perioperative management of liver transplant patients

Cirrhotic cardiomyopathy is a disease that has only recently been recognised as a definitive clinical entity. In the setting of liver cirrhosis, it is characterized by a blunted inotropic and chronotropic response to stress, impaired diastolic relaxation of the myocardium and prolongation of the QT interval in the absence of other known cardiac disease. A key pathological feature is the persistent over-activation of the sympathetic nervous system in cirrhosis, which leads to down-regulation and dysfunction of the β-adrenergic receptor. Diagnosis can be made using a combination of echocardiography (resting and stress), tissue Doppler imaging, cardiac magnetic resonance imaging, 12-lead electrocardiogram and measurement of biomarkers. There are significant implications of cirrhotic cardiomyopathy in a number of clinical situations in which there is an increased physiological demand, which can lead to acute cardiac decompensation and heart failure. Prior to transplantation there is an increased risk of hepatorenal syndrome, cardiac failure following transjugular intrahepatic portosystemic shunt insertion and increased risk of arrhythmias during acute gastrointestinal bleeding. Liver transplantation presents the greatest physiological challenge with a further risk of acute cardiac decompensation. Peri-operative management should involve appropriate choice of graft and minimization of large fluctuations in preload and afterload. The avoidance of cardiac failure during this period has important prognostic implications, as there is evidence to suggest a long-term resolution of the abnormalities in cirrhotic cardiomyopathy.

Prediction of perioperative cardiac events through preoperative NT-pro-BNP and cTnI after emergent non-cardiac surgery in elderly patients

Objectives

Clinical risk stratification has an important function in preoperative evaluation of patients at risk for cardiac events prior to non-cardiac surgery. The aim of this study was to determine whether the combined measurement of pre-operative N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and cardiac troponin I (cTnI) could provide useful prognostic information about postoperative major adverse cardiac events (MACE) within 30 days in patients aged over 60 years undergoing emergent non-cardiac surgery.

Methods

The study group comprised 2519 patients aged over 60 years that were undergoing emergent non-cardiac surgery between December 2007 and December 2013. NT-pro-BNP and cTnI were measured during hospital admission. The patients were monitored for MACE (cardiac death, non-fatal myocardial infarction, or cardiac arrest) during the 30-day postoperative follow-up period.

Results

MACE occurred in 251 patients (10.0%). Preoperative NT-pro-BNP and cTNI level were significantly higher in the individuals that experienced MACE than in those who did not (P < 0.001). The confounding factors of age, sex, co-morbidities and preoperative medications were adjusted in a multivariate logistic regression analysis. This analysis showed that preoperative NT-proBNP level > 917 pg/mL (OR 4.81, 95% CI 3.446–6.722, P < 0.001) and cTnI ≥ 0.07 ng/mL (OR 8.74, 95% CI 5.881–12.987, P < 0.001) remained significantly and independently associated with MACE after the adjustment of the confounding factors. Kaplan-Meier event-free survival curves demonstrated that patients with preoperative simultaneous NT-proBNP level > 917 pg/mL and cTnT ≥0.07 ng/mL had worse event-free survival than individual assessments of either biomarker.

Conclusion

Preoperative plasma NT-proBNP and cTnI are both independently associated with an increased risk of MACE in elderly patients after emergent non-cardiac surgery. The combination of these biomarkers provides better prognostic information than using either biomarker separately.