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.
Keywords: Revised Cardiac Risk Index; brain natriuretic peptide; cardiovascular risk factors; likelihood ratio tests; perioperative mortality.