B type natriuretic peptide--a diagnostic breakthrough in peri-operative cardiac risk assessment?

Use of Preoperative Natriuretic Peptide in Predicting Mortality After Coronary Artery Bypass Grafting: A Systematic Review and Meta-analysis

The objective of this systematic review was to evaluate the current evidence on the utility of preoperative B-type natriuretic peptide (BNP) and N-terminal-pro B-type natriuretic peptide (NT-proBNP) in predicting short-term and long-term mortality after coronary artery bypass grafting (CABG). OVID MEDLINE, EMBASE, SCOPUS, and PUBMED were searched from 1946 to August 2022 using the following terms: "coronary artery bypass grafting" and "BNP" and "outcomes." Eligible studies included observational studies reporting the association between preoperative BNP and NT-proBNP levels and short- and long-term mortality after CABG. Articles were selected systematically, assessed for bias, and, when possible, meta-analyzed using a random effect model. After retrieving 53 articles, 11 were included for qualitative synthesis and 4 for quantitative meta-analysis. Studies included in this review showed that elevated preoperative natriuretic peptide levels, despite variable cut-offs, have been consistently shown to be associated with short- and long-term mortality after CABG. The median BNP cut-off value was 145.5 pg/mL (25th-75th percentile 95-324.25 pg/mL), and the mean NT-proBNP value was 765 ± 372 pg/mL. Compared to patients with normal natriuretic peptide levels, patients with elevated BNP and NT-proBNP presented higher mortality rates after CABG (odds ratio 3.96, 95% confidence interval 2.41-6.52; p < 0.00001). Preoperative BNP level is a powerful predictor of mortality in patients undergoing CABG. The measurement of BNP can add significant value to these patients' risk stratification and therapeutic decision-making.

Effect of intraoperative personalized goal-directed hemodynamic management on acute myocardial injury in high-risk patients having major abdominal surgery: a post-hoc secondary analysis of a randomized clinical trial

Acute myocardial injury is common after noncardiac surgery and associated with mortality. Impaired intraoperative cardiovascular dynamics are a risk factor for acute myocardial injury. Optimizing intraoperative cardiovascular dynamics may thus reduce acute myocardial injury. We aimed to investigate the effect of intraoperative personalized goal-directed hemodynamic management on the incidence of acute myocardial injury. We hypothesized that personalized goal-directed hemodynamic management reduces the incidence of acute myocardial injury compared to routine hemodynamic management in high-risk patients having major abdominal surgery. We performed a post-hoc secondary analysis of a randomized clinical trial including 180 high-risk major abdominal surgery patients that were randomized to personalized goal-directed hemodynamic management or routine hemodynamic management. We compared the incidences of acute myocardial injury-defined according to the Fourth Universal Definition of Myocardial Infarction (2018)-between patients randomized to personalized goal-directed hemodynamic management or routine hemodynamic management by calculating the relative and absolute risk reduction together with 95% Wald confidence intervals and P values. Acute myocardial injury occurred in 4 of 90 patients (4%) in the personalized goal-directed hemodynamic management group and in 12 of 90 patients (13%) in the routine hemodynamic management group (relative risk: 0.33, 95% confidence interval: 0.11 to 0.99, P = 0.036; absolute risk reduction: - 9%, 95% confidence interval: - 17% to - 0.68%, P = 0.034). In this post-hoc secondary analysis, intraoperative personalized goal-directed hemodynamic management reduced the incidence of acute myocardial injury compared to routine hemodynamic management in high-risk patients having major abdominal surgery. This needs to be confirmed in larger prospective trials.

A comparison of intraoperative goal-directed intravenous administration of crystalloid versus colloid solutions on the postoperative maximum N-terminal pro brain natriuretic peptide in patients undergoing moderate- to high-risk noncardiac surgery

BACKGROUND

N-terminal pro brain natriuretic peptide (NT-proBNP) and troponin T are released during myocardial wall stress and/or ischemia and are strong predictors for postoperative cardiovascular complications. However, the relative effects of goal-directed, intravenous administration of crystalloid compared to colloid solutions on NT-proBNP and troponin T, especially in relatively healthy patients undergoing moderate- to high-risk noncardiac surgery, remains unclear. Thus, we evaluated in this sub-study the effect of a goal-directed crystalloid versus a goal-directed colloid fluid regimen on postoperative maximum NT-proBNP concentration. We further evaluated the incidence of myocardial injury after noncardiac surgery (MINS) between both study groups.

METHODS

Thirty patients were randomly assigned to receive additional intravenous fluid boluses of 6% hydroxyethyl starch 130/0.4 and 30 patients to receive lactated Ringer's solution. Intraoperative fluid management was guided by oesophageal Doppler-according to a previously published algorithm. The primary outcome were differences in postoperative maximum NT-proBNP (maxNT-proBNP) between both groups. As our secondary outcome we evaluated the incidence of MINS between both study groups. We defined maxNT-proBNP as the maximum value measured within 2 h after surgery and on the first and second postoperative day.

RESULTS

In total 56 patients were analysed. There was no significant difference in postoperative maximum NT-proBNP between the colloid group (258.7 ng/L (IQR 199.4 to 782.1)) and the crystalloid group (440.3 ng/L (IQR 177.9 to 691.2)) during the first 2 postoperative days (P = 0.29). Five patients in the colloid group and 7 patients in the crystalloid group developed MINS (P = 0.75).

CONCLUSIONS

Based on this relatively small study goal-directed colloid administration did not decrease postoperative maxNT-proBNP concentration as compared to goal-directed crystalloid administration.

TRIAL REGISTRATION

ClinicalTrials.gov ( NCT01195883 ) Registered on 6th September 2010.

The effect of supplemental oxygen on perioperative brain natriuretic peptide concentration in cardiac risk patients - a protocol for a prosprective randomized clinical trial

BACKGROUND

Elevated postoperative N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are predictive for cardiac adverse events in noncardiac surgery. Studies indicate that supplemental oxygen decreases sympathetic nerve activity and might, therefore, improve cardiovascular function. Thus, we will test the effect of perioperative supplemental oxygen administration on NT-proBNP release after surgery.

METHODS/DESIGN

We will conduct a single-center, double-blinded, randomized trial at the Medical University of Vienna, including 260 patients with increased cardiac risk factors undergoing moderate- to high-risk noncardiac surgery. Patients will be randomly assigned to receive 80% versus 30% oxygen during surgery and for 2 h postoperatively. The primary outcome will be the difference in maximum NT-proBNP release after surgery. As secondary outcomes we will assess the effect of supplemental oxygen on postoperative maximum troponin T concentration, oxidation-reduction potential, von Willebrand factor concentration and perioperative fluid requirements. We will perform outcome measurements 2 h after surgery, on postoperative day 1 and on postoperative day 3. The NT-proBNP concentration and the oxidation-reduction potential will also be measured within 72 h before discharge.

DISCUSSION

Our trial should determine whether perioperative supplemental oxygen administration will reduce the postoperative release of NT-proBNP in patients with preoperative increased cardiovascular risk factors undergoing noncardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03366857. Registered on 8th December 2017.

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.

Predicting the occurrence of major adverse cardiac events within 30 days of a vascular surgery: an empirical comparison of the minimum p value method and ROC curve approach using individual patient data meta-analysis

We aimed to compare the minimum p value method and the area under the receiver operating characteristics (ROC) curve approach to categorize continuous biomarkers for the prediction of postoperative 30-day major adverse cardiac events in noncardiac vascular surgery patients. Individual-patient data from six cohorts reporting B-type natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NTproBNP) were obtained. These biomarkers were dichotomized using the minimum p value method and compared with previously reported ROC curve-derived thresholds using logistic regression analysis. A final prediction model was developed, internally validated, and assessed for its sensitivity to clustering effects. Finally, a preoperative risk score system was proposed. Thresholds identified by the minimum p value method and ROC curve approach were 115.57 pg/ml (p < 0.001) and 116 pg/ml for BNP, and 241.7 pg/ml (p = 0.001) and 277.5 pg/ml for NTproBNP, respectively. The minimum p value thresholds were slightly stronger predictors based on our logistic regression analysis. The final model included a composite predictor of the minimum p value method’s BNP and NTproBNP thresholds [odds ratio (OR) = 8.5, p < 0.001], surgery type (OR = 2.5, p = 0.002), and diabetes (OR = 2.1, p = 0.015). Preoperative risks using the scoring system ranged from 2 to 49 %. The minimum p value method and ROC curve approach identify similar optimal thresholds. We propose to replace the revised cardiac risk index with our risk score system for individual-specific preoperative risk stratification after noncardiac nonvascular surgery.

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.

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.

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

B-Type natriuretic peptides and troponin measurements have potential in predicting risk in patients undergoing non-cardiac surgery. Using the American Heart Association framework for the evaluation of novel biomarkers, we review the current evidence supporting the peri-operative use of these two biomarkers. In patients having major non-cardiac surgery who are risk stratified using clinical risk scores, the measurement of natriuretic peptides and troponin, both before and after surgery, significantly improves risk stratification. However, only pre- and postoperative natriuretic peptide measurement and postoperative troponin measurement have shown clinical utility. It is now important for trials to be conducted to determine whether integrating pre- and postoperative natriuretic peptide and postoperative troponin measurement into clinical practice is able to improve clinical outcomes in patients undergoing non-cardiac surgery.

Clinical use of ultrasensitive cardiac troponin I assay in intermediate- and high-risk surgery patients

Background. Cardiac troponin levels have been reported to add value in the detection of cardiovascular complications in noncardiac surgery. A sensitive cardiac troponin I (cTnI) assay could provide more accurate prognostic information. Methods. This study prospectively enrolled 142 patients with at least one Revised Cardiac Risk Index risk factor who underwent noncardiac surgery. cTnI levels were measured postoperatively. Short-term cardiac outcome predictors were evaluated. Results. cTnI elevation was observed in 47 patients, among whom 14 were diagnosed as having myocardial infarction (MI). After 30 days, 16 patients had major adverse cardiac events (MACE). Excluding patients with a final diagnosis of MI, predictors of cTnI elevation included dialysis, history of heart failure, transoperative major bleeding, and elevated levels of pre- and postoperative N-terminal pro-B-type natriuretic peptide (NT-proBNP). Maximal cTnI values showed the highest sensitivity (94%), specificity (75%), and overall accuracy (AUC 0.89; 95% CI 0.80–0.98) for postoperative MACE. Postoperative cTnI peak level (OR 9.4; 95% CI 2.3–39.2) and a preoperative NT-proBNP level ≥917 pg/mL (OR 3.47; 95% CI 1.05–11.6) were independent risk factors for MACE. Conclusions. cTnI was shown to be an independent prognostic factor for cardiac outcomes and should be considered as a component of perioperative risk assessment.

Postoperative B-type natriuretic peptide for prediction of major cardiac events in patients undergoing noncardiac surgery: systematic review and individual patient meta-analysis

BACKGROUND

It is unclear whether postoperative B-type natriuretic peptides (i.e., BNP and N-terminal proBNP) can predict cardiovascular complications in noncardiac surgery.

METHODS

The authors undertook a systematic review and individual patient data meta-analysis to determine whether postoperative BNPs predict postoperative cardiovascular complications at 30 and 180 days or more.

RESULTS

The authors identified 18 eligible studies (n = 2,051). For the primary outcome of 30-day mortality or nonfatal myocardial infarction, BNP of 245 pg/ml had an area under the curve of 0.71 (95% CI, 0.64-0.78), and N-terminal proBNP of 718 pg/ml had an area under the curve of 0.80 (95% CI, 0.77-0.84). These thresholds independently predicted 30-day mortality or nonfatal myocardial infarction (adjusted odds ratio [AOR] 4.5; 95% CI, 2.74-7.4; P < 0.001), mortality (AOR, 4.2; 95% CI, 2.29-7.69; P < 0.001), cardiac mortality (AOR, 9.4; 95% CI, 0.32-254.34; P < 0.001), and cardiac failure (AOR, 18.5; 95% CI, 4.55-75.29; P < 0.001). For greater than or equal to 180-day outcomes, natriuretic peptides independently predicted mortality or nonfatal myocardial infarction (AOR, 3.3; 95% CI, 2.58-4.3; P < 0.001), mortality (AOR, 2.2; 95% CI, 1.67-86; P < 0.001), cardiac mortality (AOR, 2.1; 95% CI, 0.05-1,385.17; P < 0.001), and cardiac failure (AOR, 3.5; 95% CI, 1.0-9.34; P = 0.022). Patients with BNP values of 0-250, greater than 250-400, and greater than 400 pg/ml suffered the primary outcome at a rate of 6.6, 15.7, and 29.5%, respectively. Patients with N-terminal proBNP values of 0-300, greater than 300-900, and greater than 900 pg/ml suffered the primary outcome at a rate of 1.8, 8.7, and 27%, respectively.

CONCLUSIONS

Increased postoperative BNPs are independently associated with adverse cardiac events after noncardiac surgery.

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

OBJECTIVES

The objective of this study was to determine whether measuring post-operative B-type natriuretic peptides (NPs) (i.e., B-type natriuretic peptide [BNP] and N-terminal fragment of proBNP [NT-proBNP]) enhances risk stratification in adult patients undergoing noncardiac surgery, in whom a pre-operative NP has been measured.

BACKGROUND

Pre-operative NP concentrations are powerful independent predictors of perioperative cardiovascular complications, but recent studies have reported that elevated post-operative NP concentrations are independently associated with these complications. It is not clear whether there is value in measuring post-operative NP when a pre-operative measurement has been done.

METHODS

We conducted a systematic review and individual patient data meta-analysis to determine whether the addition of post-operative NP levels enhanced the prediction of the composite of death and nonfatal myocardial infarction at 30 and ≥180 days after surgery.

RESULTS

Eighteen eligible studies provided individual patient data (n = 2,179). Adding post-operative NP to a risk prediction model containing pre-operative NP improved model fit and risk classification at both 30 days (corrected quasi-likelihood under the independence model criterion: 1,280 to 1,204; net reclassification index: 20%; p < 0.001) and ≥180 days (corrected quasi-likelihood under the independence model criterion: 1,320 to 1,300; net reclassification index: 11%; p = 0.003). Elevated post-operative NP was the strongest independent predictor of the primary outcome at 30 days (odds ratio: 3.7; 95% confidence interval: 2.2 to 6.2; p < 0.001) and ≥180 days (odds ratio: 2.2; 95% confidence interval: 1.9 to 2.7; p < 0.001) after surgery.

CONCLUSIONS

Additional post-operative NP measurement enhanced risk stratification for the composite outcomes of death or nonfatal myocardial infarction at 30 days and ≥180 days after noncardiac surgery compared with a pre-operative NP measurement alone.

Biomonitors of cardiac injury and performance: B-type natriuretic peptide and troponin as monitors of hemodynamics and oxygen transport balance

Serum biomarkers, such as B-type natriuretic peptide and troponin, are frequently measured in the cardiac intensive care unit. A review of the evidence supporting monitoring of these biomarkers is presented.

DESIGN

A search of MEDLINE, PubMed, and the Cochrane Database was conducted to find literature regarding the use of B-type natriuretic peptide and troponin in the cardiac intensive care setting. Adult and pediatric data were considered.

RESULTS AND CONCLUSION

Both B-type natriuretic peptide and troponin have demonstrated utility in the intensive care setting but there is no conclusive evidence at this time that either biomarker can be used to guide inpatient management of children with cardiac disease. Although B-type natriuretic peptide and troponin concentrations can alert clinicians to myocardial stress, injury, or hemodynamic alterations, the levels can also be elevated in a variety of clinical scenarios, including sepsis. Observational studies have demonstrated that perioperative measurement of these biomarkers can predict postoperative mortality and complications.

RECOMMENDATION AND LEVEL OF EVIDENCE

(class IIb, level of evidence B): The use of B-type natriuretic peptide and/or troponin measurements in the evaluation of hemodynamics and postoperative outcome in pediatric cardiac patients may be beneficial.

[Cardiac biomarkers in perioperative risk stratification]

OBJECTIVES

The field of new cardiac biomarkers has triggered physicians' enthusiasm because of their potential diagnostic and prognostic values for routine clinical practice in the surgical setting. The objective of the present article is to review the role of new cardiac biomarkers and their potential additive clinical value in predicting short- and long-term risk following cardiac and non-cardiac surgery.

DATA SOURCES

A PubMed(®) database research in English and French languages published until June 2010. Keywords were cardiac biomarkers, troponins, cardiac troponin I (cTnI), natriuretic peptides, B-type natriuretic peptide (BNP), C-reactive protein (CRP), multiple markers approach, risk stratification, clinical risk scores.

DATA SYNTHESIS

Numerous publications deal with the diagnostic and prognostic values of new cardiac biomarkers in cardiac and non-cardiac surgical settings and provide an increasing evidence of their interest, validating different hierarchical steps which are mandatory before recommending a wide use of biomarkers for routine practice. Even if the first studies demonstrating an additional prognostic value of serum postoperative cTnI and/or preoperative BNP when compared with clinical predictive models are now available, we still lack data concerning an actual positive impact of new biomarkers measurements on clinical decision making or practice, as well as patient care and outcome.

CONCLUSIONS

While use of new cardiac biomarkers in the perioperative period appears to be a simple and objective tool for risk stratification at the bedside, we still need to remain cautious concerning their additional clinical value on existing predictive models for routine practice.

Influence of preoperative serum N-terminal pro-brain type natriuretic peptide on the postoperative outcome and survival rates of coronary artery bypass patients

BACKGROUND

The N-terminal fragment of pro-brain type natriuretic peptide (NT-proBNP) is an established biomarker for cardiac failure.

OBJECTIVE

To determine the influence of preoperative serum NT-proBNP on postoperative outcome and mid-term survival in patients undergoing coronary artery bypass grafting (CABG).

METHODS

In 819 patients undergoing isolated CABG surgery preoperative serum NT-proBNP levels were measured. NT-proBNP was correlated with various postoperative outcome parameters and survival rate after a median follow-up time of 18 (0.5-44) months. Risk factors of mortality were identified using χ², Mann-Whitney test, and Cox regression.

RESULTS

NT-proBNP levels > 430 ng/ml and > 502 ng/ml predicted hospital and overall mortality (p < 0.05), with an incidence of 1.6% and 4%, respectively. Kaplan-Meier analysis revealed decreased survival rates in patients with NT-proBNP > 502 ng/ml (p = 0.001). Age, preoperative serum creatinine, diabetes, chronic obstructive pulmonary disease, low left ventricular ejection fraction and BNP levels >502 ng/ml were isolated as risk factors for overall mortality. Multivariate Cox regression analysis, including the known factors influencing NT-proBNP levels, identified NT-proBNP as an independent risk factor for mortality (OR = 3.079 (CI = 1.149-8.247), p = 0.025). Preoperative NT-proBNP levels >502 ng/ml were associated with increased ventilation time (p = 0.005), longer intensive care unit stay (p=0.001), higher incidence of postoperative hemofiltration (p = 0.001), use of intra-aortic balloon pump (p < 0.001), and postoperative atrial fibrillation (p = 0.031)

CONCLUSION

Preoperative NT-proBNP levels > 502 ng/ml predict mid-term mortality after isolated CABG and are associated with significantly higher hospital mortality and perioperative complications.

CORRESPONDENCE

Dr Collinson (vol 70(6), 2009, p. M84) highlighted the role of B-type natriuretic peptide (BtNP) in cardiac failure. In addition to the mentioned uses of BtNP in primary care and in diagnosis of acute heart failure, the authors believe that BtNP has an important role in anaesthesia, particularly in the perioperative assessment of cardiac risk.