title: B-type natriuretic peptide in patients undergoing orthopaedic surgery: a prospective cohort study.
abstract: OBJECTIVE
  Postoperative cardiac complications pose a substantial risk to patients undergoing orthopaedic surgery.
  
  
  METHODS
  B-type natriuretic peptide (BNP) was determined preoperatively in 270 patients undergoing scheduled orthopaedic surgery. The accuracy of BNP to predict the occurrence of in-hospital cardiac events was evaluated as the primary endpoint. Cardiac events at 1 year of follow-up were considered secondary endpoints.
  
  
  RESULTS
  Preoperative BNP levels were significantly higher in the four patients experiencing in-hospital cardiac events than in patients without events [median 306 pg ml(-1) (range 123-3958) vs. 35 pg ml(-1) (range 14-2074), P = 0.01]. In a receiver operating characteristic analysis for the prediction of in-hospital cardiac events, the area under the receiver operating characteristic curve for BNP was 0.86 (95% confidence interval 0.74-0.99). The optimal predictive accuracy was achieved with a BNP threshold of 174 pg ml(-1). Importantly, the combination of BNP and the American Society of Anesthesiologists score further improved this accuracy. Additionally, BNP retained a high predictive accuracy in the subgroup of patients with known cardiac diseases [area under the receiver operating characteristic curve 0.85 (95% confidence interval from 0.65 to <1)]. The area under the receiver operating characteristic curve for the prediction of long-term cardiac events by BNP was 0.71 (95% confidence interval 0.57-0.84).
  
  
  CONCLUSIONS
  In patients undergoing orthopaedic surgery, preoperative BNP levels can predict short-term and long-term postoperative cardiac events. Despite the paucity of endpoint events observed in this study, our results are in agreement with all prior investigations. BNP used in addition to an American College of Cardiology/American Heart Association guideline-based risk assessment might, therefore, be a useful tool in the preoperative evaluation of patients undergoing orthopaedic surgery.
authors.affiliation: Department of Internal Medicine, University Hospital Basel, Basel, Switzerland. breidthardtt@uhbs.ch
authors.forename: Tobias
authors.initials: T
authors.lastname: Breidthardt
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Kindler
authors.forename: Christian
authors.initials: C
authors.lastname: Schindler
authors.forename: Moreno
authors.initials: M
authors.lastname: Futterer
authors.forename: Keiko
authors.initials: K
authors.lastname: Yonekawa
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D019637:Orthopedic Procedures / Q000009:adverse effects*; D005791:Patient Care / Q000379:methods; D011183:Postoperative Complications / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain