Assessment of preoperative B-type natriuretic peptide in adult surgeries: is it useful?

Prognostic Value of Preoperative Pro-B-Type Natriuretic Peptide: Early Predictor of Cardiovascular Complications and Mortality After Major Abdominal Surgery

Background and objectives

In surgical patients, coronary disease is the main cause of perioperative mortality. The incidence of serious cardiovascular complications is reported as 5% with a probability of 1-2% of death from the cardiac cause in major non-cardiac surgery. B-type natriuretic peptide (BNP) is a sensitive and specific predictor of left ventricular systolic dysfunction and predicts first cardiovascular event and death in the general population. The recent guidelines recommended the use of pro-BNP for independent perioperative prognosis in cardiac patients undergoing non-cardiac surgery. The aim of this study is to assess the predictive value of raised pro-BNP levels in patients who underwent major abdominal surgery and evaluate its relationship with cardiovascular complications and mortality occurring up to 30 days after surgery.

Materials and methods

We reviewed the medical records of patients undergone surgical procedures in the abdominal region lasting more than two hours, requiring postoperative high dependence or intensive care and an expected hospital stay of at least three days. All types of open or laparoscopic-assisted abdominal or pelvic surgeries that were evaluated for preoperative pro-BNP levels were included in the study. During the postoperative period, all patients were followed for cardiac complications and mortality for 30 days after surgery. Postoperative adverse cardiac events were predefined as angina pectoris, myocardial infarction, cardiogenic dyspnea, acute arrhythmias (atrial fibrillation/flutter, ventricular fibrillation/tachycardia), acute hypertensive event (hypertensive emergency or urgency), congestive heart failure, acute pulmonary edema, or primary cardiac death. While non-cardiac complications were also documented as either pulmonary, septic, postsurgical site infection, and other systemic complications. Subsequently, a survival analysis was done for the discretion of cardiovascular complications and mortality.

Results

The mean age of the study population was found to be 50.22 ± 14.28 years, mean pro-BNP levels were 909.29 ± 3950.04, and mean days of hospital stay were 7.43 ± 4.49 days. The 30-day postoperative all-cause mortality was found to be 9.8%. Hypertension and diabetes were frequent comorbidities amongst the study population. The mean preoperative pro-BNP levels were found higher in the male gender (p=0.071), also found higher in those with cardiovascular complications (p=0.006) and mortality (p=0.057). Receiver operating characteristic (ROC) analysis showed cardiovascular outcomes with a cut-off value of pro-BNP at 143 pg/ml, AUC of 0.891, at a sensitivity of 91%, positive predictive value (PPV) of 96%, a specificity of 75%, and negative predictive value (NPV) of 58%, while the same for mortality at a cut-off value of 164 pg/ml was found with AUC of 0.815, at a sensitivity of 84%, a specificity of 66%, PPV of 97%, and NPV of 21%. The unadjusted odds ratio for cardiovascular complications was found to be 17.857 (95% CI: 6.56-48.60) while that for mortality was 10.863 (95% Cl: 2.29-51.37). The Kaplan-Meier survival curves showing elevated pro-BNP levels were significantly associated with cardiovascular events, with 30 days mortality at a cut-off value of 164 pg/ml.

Conclusion

Pro-BNP is a useful marker in postoperative patients for not only predicting cardiovascular outcomes as cited by many previous studies but also mortality.

Rise and fall of NT-proBNP in aortic valve intervention

Objectives

To describe the dynamics of N-terminal pro-B-type natriuretic peptide (NT-proBNP) from preoperative evaluation to 6-month follow-up in patients undergoing aortic valve intervention, and to evaluate NT-proBNP with regard to 1-year mortality.

Methods

At preoperative evaluation, we prospectively included 462 patients accepted for aortic valve intervention. The median time to surgical aortic valve replacement (SAVR; n=336) or transcatheter aortic valve implantation (TAVI; n=126) was 4 months. NT-proBNP was measured at enrolment for preoperative evaluation, on the day of surgery, postoperatively on day 1, day 3 and at the 6-month follow-up. Subgroups of patients undergoing SAVR with aortic regurgitation and aortic stenosis with and without coronary artery bypass were also analysed.

Results

NT-proBNP remained stable in all subgroups during the preoperative waiting period, but displayed a substantial transient early postoperative increase with a peak on day 3 except in the TAVI group, which peaked on day 1. At the 6-month follow-up, NT-proBNP had decreased to or below the preoperative level in all groups. In the SAVR group, NT-proBNP preoperatively and on postoperative days 1 and 3 revealed significant discriminatory power with regard to 1-year mortality (area under the curve (AUC)=0.79, P=0.0001; AUC=0.71, P=0.03; and AUC=0.79, P=0.002, respectively). This was not found in the TAVI group, which had higher levels of NT-proBNP both preoperatively and at the 6-month follow-up compared with the SAVR group.

Conclusions

The dynamic profile of NT-proBNP differed between patients undergoing TAVI and SAVR. NT-proBNP in the perioperative course was associated with increased risk of 1-year mortality in SAVR but not in TAVI.

The Possible Use of Preoperative Natriuretic Peptides for Discriminating Low Versus Moderate-High Surgical Risk Patient

Perioperative risk scores for patients undergoing noncardiac surgery are generally considered inaccurate, poor, or, at best, modest. We propose estimating a patient’s pretest and posttest probability of cardiac morbidity and death using the preoperative scoring system plus the negative likelihood ratio from brain natriuretic peptide (BNP) or N-terminal proB-type natriuretic peptide (NT-proBNP) plasma levels. Our clinical challenge scenario showed a pretest probability of postoperative major cardiac complications with the patient risk factor as 6.6% for the Revised Cardiac Risk Index and between 1% and 5% (intermediate risk) per the recent European Society of Cardiology and the European Society of Anesthesiologist guidelines for surgical risk estimation. In fact, the American College of Cardiology and the American Heart Association guidelines consider the same surgical procedure for elevated risk. The posttest probability takes advantage of a negative likelihood ratio from BNP plasma levels, with patient risk factor reduced to 0.8% and surgical risk to 1.1%. In the same way, the pretest American College of Surgeons National Surgical Quality Improvement Program score decreased from 18.8% to 3.5% for severe complications and from 0.9% to 0.1% for death at ≤90 days. Following noncardiac surgery, postoperative complications and mortality are often cardiac in nature. The negative likelihood ratio of BNP and NT-proBNP plasma levels provides a quick, low-cost tool for recognizing and reclassifying the cardiovascular risk of those undergoing noncardiac surgery, thereby singling out low- versus moderate-high-risk surgical patients.

Peri-operative management of older people undergoing surgery

Increasing numbers of older people are undergoing both emergency and elective surgery. However, they remain at increased risk of adverse outcome in comparison with younger patients. This may relate to the association of ageing with physiological deterioration, multi-morbidity and geriatric syndromes such as frailty, all of which are independent predictors of adverse post-operative outcome. Although there is an emerging evidence base for the identification and management of these predictors, this has not yet translated into routine clinical practice. Older patients undergoing surgery often receive sub-optimal care and surgical pathways are not well suited to complex older patients with multi-pathology. Evidence is emerging for alternative models of care that incorporate the evolving evidence base for optimal peri-operative management of the older surgical patient, including risk assessment and optimization. This article aims to provide a practical overview of the literature to all disciplines working in this field.

Prognostic power of pre- and postoperative B-type natriuretic peptide levels in patients undergoing abdominal aortic surgery

OBJECTIVES

The first aim of the present study was to evaluate the pre- and postoperative B-type natriuretic peptide (BNP) levels in patients undergoing surgery for repair of an infrarenal abdominal aortic aneurysm (AAA) and analyze their power as a predictor of in-hospital cardiac events. The second aim was to evaluate the association among pre- and postoperative BNP levels, postoperative patient complications, and length of hospital stay.

DESIGN

Prospective observational study.

SETTING

A university hospital.

PARTICIPANTS

Forty-five patients undergoing elective surgery for an abdominal aortic aneurysm.

INTERVENTIONS

The plasma BNP level was assessed just before surgery and then on postoperative day 1. Cardiac troponin I levels were measured postoperatively on arrival to the intensive care unit (time 0) and then 12, 48, and 72 hours later.

MEASUREMENTS AND MAIN RESULTS

The preoperative BNP concentration in patients who developed an acute myocardial infarction was 209 (IQR 84-346) pg/mL compared with 74 (IQR 28-142) pg/mL in those who did not. The difference between groups was statistically significant (p = 0.04). The Spearman correlation showed that postoperative BNP levels correlated significantly with preoperative BNP levels (r = 0.73, p = 0.0001), length of hospital stay (r = 0.35, p = 0.04), and troponin I concentration at 0 hour (r = 0.42, p = 0.02), 12 hours (r = 0.51, p = 0.0052), and 48 hours (r = 0.40, p = 0.033). In contrast, preoperative BNP levels correlated with troponin I at only 12 hours (r = 0.34, p = 0.02). Postoperative BNP levels were influenced significantly by transfusions (p = 0.035) and cross-clamping times (p = 0.038).

CONCLUSIONS

The present results confirm the high negative predictive value of preoperative BNP levels; and postoperative BNP levels showed a better correlation with postoperative troponin levels, blood transfusion, and postoperative cardiac events.