NPPB and heart failure: For future studies, it would likewise be useful to determine and obtain data on pertinent parameters for coronary artery disease and heart failure such as functional class (e.g. Canadian Cardiovascular Society class for angina and New York Heart Association class for HF), ischemia burden, involved epicardial coronary arteries on angiogram, ejection fraction and other echocardiographic parameters, baseline and in-hospital cardiac troponins and NT pro-BNP levels, if available.