Association of Endothelial Function and Clinical Outcomes in Subjects Admitted to Chest Pain Unit

All subjects admitted to the CPU with low to moderate probability for CAD and negative troponin, will undergo the following tests upon arrival following clinical evaluation and their consenting to the study: resting ECG, EndoPAT testing and then after stress nuclear imaging or stress echocardiography. Except for EndoPAT testing, all other tests will be conducted according to the routine CPU protocol. The results of the EndoPAT will be blinded to the treating physician until the end of the study and all patients will be managed according to the current CPU protocol, including 24-h Holter monitoring, repeat resting ECG and exercise tests (nuclear SPECT imaging or stress echocardiography, whichever is available) in addition to repeat clinical and troponin tests evaluations. All clinical data of the recruited subjects the will be recorded and evaluated after completion of the study. Long-term clinical follow-up All patients will be followed by telephone contact after 6 and 12 months for combined major adverse cardiovascular end-points (MACE) which include all-cause mortality, non-fatal myocardial infarction, hospitalization for heart failure or angina pectoris, stroke, coronary artery bypass grafting and percutaneous coronary interventions, by physicians who will be blinded to the patients' baseline clinical status and endothelial function (assessed by EndoPAT) results. All MACE will be validated by review of medical records by senior cardiologists blinded to the endothelial function results. In addition, on-line access to this information will facilitate verification and safe documentation of all events. In addition, written medical records will be reviewed by cardiologists in the event of any death, hospitalization and/or angina pectoris. At the end of the study the cost effectiveness on prediction of short (in-hospital) and long (6 months, and 1 year) of EndoPAT will be assessed and will be compared to the stress tests (nuclear imaging and/or echocardiography).