Prediction of early postoperative major cardiac events after elective orthopedic surgery: the role of B-type natriuretic peptide, the revised cardiac risk index, and ASA class

Background: The aim of this study was to evaluate pre- and post-operative brain natriuretic peptide (BNP) levels and compare the power of this test in predicting in-hospital major adverse cardiac events (MACE: atrial fibrillation, flutter, acute heart failure or non-fatal/fatal myocardial infarction) in patients undergoing elective prosthesis orthopedic surgery to that of the Revised Cardiac Risk Index (RCRI) and American Society of Anesthesiology (ASA) class, the most useful scores identified to date. Methods: The study was an observational study of consecutive patients undergoing elective prosthesis orthopedic surgery. Surgical risk was established using RCRI score and ASA class criteria. Venous blood was sampled before surgery and on postoperative day 1 for the measurement of BNP. The intraoperative data collected included details of the surgery and anesthesia and any MACE experienced up until hospital discharge. Results: MACE occurred in 14 of the 227 patients treated (6.2%). Age was statistical associated with MACE (p < 0.004). Preoperative BNP levels were higher (p < 0.0007) in patients who experienced MACE than in event-free patients (median values: 92 and 35 pg/mL, respectively). Postoperative BNP levels were also greater (p < 0.0001) in patients sustaining MACE than in event-free patients (median values: 165 and 45 pg/mL, respectively). ROC curve analysis demonstrated that for a cut-off point ≥ 39 pg/mL, the area under the curve for preoperative BNP was equal to 0.77, while a postoperative BNP cut-off point ≥ 69 pg/mL gave an AUC of 0.82. Conclusions: Both pre- and post-operative BNP concentrations are predictors of MACE in patients undergoing elective prosthesis orthopedic surgery.