A 32-year-old woman with nonanginal chest pain has a 1% chance of coronary stenosis.70 72 Other clinical characteristics that improved the accuracy of prediction include active or recent smoking, Q-wave or ST-T-wave changes on the ECG, hyperlipidemia (defined at the time of study as a total cholesterol level .250 mg/dL), and diabetes mellitus (defined at that time as a fasting glucose level .140 mg/dL). Of these characteristics, Table 6. Three Principal Presentations of UA Rest angina Angina occurring at rest and usually prolonged .20 min, occurring within 1 wk of presentation New-onset angina Angina of at least CCS Class III severity with onset within 2 mo of initial presentation Increasing angina Previously diagnosed angina that is distinctly more frequent, longer in duration, or lower in threshold (ie, increased by $1 CCS class within 2 mo of initial presentation to at least CCS Class III severity) CCS indicates Canadian Cardiovascular Society. Reproduced from Braunwald.50 Table 7. Alternative Diagnoses to Angina for Patients With Chest Pain Nonischemic Cardiovascular Pulmonary Gastrointestinal Chest Wall Psychiatric Aortic dissection Pulmonary embolism Esophageal Esophagitis Spasm Reflux Costochondritis Fibrositis Rib fracture Sternoclavicular arthritis Herpes zoster (before the rash) Anxiety disorders Hyperventilation Panic disorder Primary anxiety Pericarditis Pneumothorax Pneumonia Pleuritis Biliary Colic Cholecystitis Choledocholithiasis Cholangitis Peptic ulcer Pancreatitis Affective disorders (ie, depression) Somatiform disorders Thought disorders (ie, fixed delusions) Reproduced from Gibbons et al.7 diabetes mellitus had the greatest influence on increasing the probability of IHD. The presence of hypertension or a family history of premature IHD did not provide additional predic- tive accuracy. The results of the aforementioned landmark study subsequently were replicated with data from CASS (Coronary Artery Surgery Study)73 and were within 5% of the original estimates for 23 of 24 patient groupings. 