NPPB and myocardial infarction: Wijeysundera et al. [20] in a prospective study reported a more objective method of assessing preoperative risk stratification for cardiac events and morbidity, relying on Duke Activity Status Index (DASI) questionnaires, CPET and NT pro-BNP testing rather than MET score alone to predict 30-day postoperative mortality or myocardial infarction.