NT-proBNP as a Risk Predictor in Emergent Surgery
NT-proBNP as a Risk Predictor in Emergent Surgery
Background Patients undergoing emergency surgery continue to be at very high risk, but accurate risk identification for the individual patient remains difficult. This study tested the usefulness of perioperative N-terminal pro B-type natriuretic peptide (NT-proBNP) for in-hospital and long-term risk stratification.
Methods We conducted a prospective single-centre observational cohort study in an Austrian university hospital. Two hundred and ninety-seven consecutive patients >50 yr of age undergoing a variety of emergency non-cardiac procedures were included. The primary endpoint was a composite of non-fatal myocardial infarction (MI), acute heart failure, or death between index surgery and 3 yr follow-up. The secondary endpoint was in-hospital major adverse cardiac events (MACE), defined as non-fatal MI, acute heart failure, or cardiac death.
Results During a median follow-up of 34 months (inter-quartile range: 16–39), 31% of subjects reached the primary endpoint. A preoperative NT-proBNP ≥725 pg ml was associated with a 4.8-fold univariate relative risk [95% confidence interval (CI): 3.1–7.6] and a postoperative NT-proBNP ≥1600 pg ml was associated with a four-fold univariate relative risk (95% CI: 2.7–6.2) for reaching the primary endpoint. Moreover, preoperative NT-proBNP remained a significant and independent (hazards ratio 1.91, 95% CI 1.08–3.37, P=0.027) predictor in a multivariate Cox proportional hazards model. A preoperative NT-proBNP ≥1740 pg ml was associated with a 6.9-fold univariate relative risk (95% CI: 3.5–13.4) for MACE during the index hospital stay, but did not remain significant in a multivariate logistic regression model.
Conclusions Preoperative NT-proBNP can help identify patients at high risk for adverse long-term outcome after emergency surgery.
Major emergency surgery, particularly in the elderly, carries up to 30% risk of in-hospital cardiac complications associated with 10–70% of in-hospital mortality. Moreover, postoperative complications have a huge impact on long-term survival. At the same time, emergency patients are least likely to undergo formal risk stratification.
The American College of Cardiology/American Heart Association's perioperative guidelines strongly emphasize functional status as a tool for risk stratification. However, emergency surgery patients often have limited preoperative physical activity due to advanced age, frailty, and comorbidities such as peripheral vascular disease, which makes accurate assessment of cardiac risk difficult.
B-type natriuretic peptides (BNPs) perform better than traditional clinical risk scores and preoperative diagnostic tests, and are relatively cheap and non-invasive. BNP is released from cardiac myocytes in response to ischaemia and myocardial stretch. Plasma levels of these peptides correlate well with the extent of inducible ischaemia and reflect the severity of heart failure. The ability of preoperative BNPs to predict early and long-term cardiovascular events and all-cause mortality after elective non-cardiac surgery has been established. Lately, their role in the perioperative setting was extended to septic patients. In patients undergoing elective vascular surgery, we demonstrated that a single postoperative determination of N-terminal proBNP (NT-proBNP) provides additional important short- and long-term prognostic information, presumably by reflecting the dynamic consequences of anaesthesia and surgery exerted by catecholamine surges and hypercoagulability with their potential to precipitate myocardial ischaemia and dysfunction.
Although currently no consensus exists regarding the reference range of pre- and postoperative BNP and NT-proBNP levels, the specifics of emergency surgery suggest an enhanced stress reaction and consequently elevated perioperative levels of BNPs compared with levels in elective surgery, as demonstrated by previous studies in selected patients. We therefore aimed to test the usefulness of pre- and postoperative NT-proBNP for in-hospital and long-term risk stratification in patients undergoing a variety of emergency surgery procedures.
Abstract and Introduction
Abstract
Background Patients undergoing emergency surgery continue to be at very high risk, but accurate risk identification for the individual patient remains difficult. This study tested the usefulness of perioperative N-terminal pro B-type natriuretic peptide (NT-proBNP) for in-hospital and long-term risk stratification.
Methods We conducted a prospective single-centre observational cohort study in an Austrian university hospital. Two hundred and ninety-seven consecutive patients >50 yr of age undergoing a variety of emergency non-cardiac procedures were included. The primary endpoint was a composite of non-fatal myocardial infarction (MI), acute heart failure, or death between index surgery and 3 yr follow-up. The secondary endpoint was in-hospital major adverse cardiac events (MACE), defined as non-fatal MI, acute heart failure, or cardiac death.
Results During a median follow-up of 34 months (inter-quartile range: 16–39), 31% of subjects reached the primary endpoint. A preoperative NT-proBNP ≥725 pg ml was associated with a 4.8-fold univariate relative risk [95% confidence interval (CI): 3.1–7.6] and a postoperative NT-proBNP ≥1600 pg ml was associated with a four-fold univariate relative risk (95% CI: 2.7–6.2) for reaching the primary endpoint. Moreover, preoperative NT-proBNP remained a significant and independent (hazards ratio 1.91, 95% CI 1.08–3.37, P=0.027) predictor in a multivariate Cox proportional hazards model. A preoperative NT-proBNP ≥1740 pg ml was associated with a 6.9-fold univariate relative risk (95% CI: 3.5–13.4) for MACE during the index hospital stay, but did not remain significant in a multivariate logistic regression model.
Conclusions Preoperative NT-proBNP can help identify patients at high risk for adverse long-term outcome after emergency surgery.
Introduction
Major emergency surgery, particularly in the elderly, carries up to 30% risk of in-hospital cardiac complications associated with 10–70% of in-hospital mortality. Moreover, postoperative complications have a huge impact on long-term survival. At the same time, emergency patients are least likely to undergo formal risk stratification.
The American College of Cardiology/American Heart Association's perioperative guidelines strongly emphasize functional status as a tool for risk stratification. However, emergency surgery patients often have limited preoperative physical activity due to advanced age, frailty, and comorbidities such as peripheral vascular disease, which makes accurate assessment of cardiac risk difficult.
B-type natriuretic peptides (BNPs) perform better than traditional clinical risk scores and preoperative diagnostic tests, and are relatively cheap and non-invasive. BNP is released from cardiac myocytes in response to ischaemia and myocardial stretch. Plasma levels of these peptides correlate well with the extent of inducible ischaemia and reflect the severity of heart failure. The ability of preoperative BNPs to predict early and long-term cardiovascular events and all-cause mortality after elective non-cardiac surgery has been established. Lately, their role in the perioperative setting was extended to septic patients. In patients undergoing elective vascular surgery, we demonstrated that a single postoperative determination of N-terminal proBNP (NT-proBNP) provides additional important short- and long-term prognostic information, presumably by reflecting the dynamic consequences of anaesthesia and surgery exerted by catecholamine surges and hypercoagulability with their potential to precipitate myocardial ischaemia and dysfunction.
Although currently no consensus exists regarding the reference range of pre- and postoperative BNP and NT-proBNP levels, the specifics of emergency surgery suggest an enhanced stress reaction and consequently elevated perioperative levels of BNPs compared with levels in elective surgery, as demonstrated by previous studies in selected patients. We therefore aimed to test the usefulness of pre- and postoperative NT-proBNP for in-hospital and long-term risk stratification in patients undergoing a variety of emergency surgery procedures.
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