Plasma N-terminal pro-B-type natriuretic peptide is predictive of perioperative cardiac events in patients undergoing vascular surgery

Abstract

Background/aims: Identification of patients at high risk for perioperative cardiac events (POCE) is clinically important. This study aimed to determine whether preoperative measurement of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) could predict POCE, and compared its predictive value with that of conventional cardiac risk factors and stress thallium scans in patients undergoing vascular surgery.

Methods: Patients scheduled for non-cardiac vascular surgery were prospectively enrolled. Clinical risk factors were identified, and NT-proBNP levels and stress thallium scans were obtained. POCE was the composite of acute myocardial infarction, congestive heart failure including acute pulmonary edema, and primary cardiac death within 5 days after surgery. A modified Revised Cardiac Risk Index (RCRI) was proposed and compared with NT-proBNP; a positive result for ischemia and a significant perfusion defect (≥ 3 walls, moderate to severely decreased, reversible perfusion defect) on the thallium scan were added to the RCRI.

Results: A total of 365 patients (91% males) with a mean age of 67 years had a median NT-proBNP level of 105.1 pg/mL (range of quartile, 50.9 to 301.9). POCE occurred in 49 (13.4%) patients. After adjustment for confounders, an NT-proBNP level of > 302 pg/mL (odds ratio [OR], 5.7; 95% confidence interval [CI], 3.1 to 10.3; p < 0.001) and a high risk by the modified RCRI (OR, 3.9; 95% CI, 1.6 to 9.3; p = 0.002) were independent predictors for POCE. Comparison of the area under the curves for predicting POCE showed no statistical differences between NT-proBNP and RCRI.

Conclusions: Preoperative measurement of NT-proBNP provides information useful for prediction of POCE as a single parameter in high-risk patients undergoing noncardiac vascular surgery.

Keywords: Postoperative complications; Pro-B-type natriuretic peptide; Vascular surgical procedures.

Figure 1

Comparison of predictive power on perioperative cardiac events. The predictive power of each risk predictors was investigated and compared each other by area under curve (AUC) of ROC analysis. For Revised Cardiac Risk Index (RCRI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), AUC = 0.73 ± 0.04 (95% confidence interval [CI], 0.65 to 0.81); for NT-proBNP, 0.70 ± 0.04 (95% CI, 0.62 to 0.78); for modified RCRI, 0.68 ± 0.04 (95% CI, 0.59 to 0.80); for RCRI, 0.68 ± 0.04 (95% CI, 0.60 to 0.76). Comparison of AUC of NT-proBNP with RCRI or modified RCRI did not show statistical difference (p > 0.05 by Hanley and McNail methods). However, the predictive value of RCRI with NT-proBNP was significantly higher than the one of RCRI or modified RCRI (p = 0.015). ROC, receiver-operating characteristic.

Figure 2

Predictive value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in relation to the Revised Cardiac Risk Index (RCRI) for perioperative cardiac event (POCE)s and myocardial infarction (MI). (A) Incidence of POCE was compared by the level of NT-proBNP 302 pg/mL and the RCRI. (B) Incidence of MI was compared by the level of NT-proBNP 302 pg/mL and the RCRI. ^aDiscriminative power of the RCRI in patients with NT-proBNP < 302 pg/mL, p =0.026. ^bOdds ratio (OR), 3.2; 95% confidence interval (CI), 1.5 to 6.8; p = 0.004. ^cOR, 4.7; 95% CI, 1.2 to 19.1; p = 0.040. ^dDiscriminative power of the RCRI in patients with NT-proBNP < 302 pg/mL, p = 0.009. ^eOR, 3.4; 95% CI, 1.3 to 8.7; p = 0.017.