Endothelial Nitric Oxide Level as a Predictor of Coronary Complexity in Patients With Unstable Angina Pectoris.

Background: The Synergy Between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is an anatomic scoring system based on coronary angiography that quantifies lesion severity and complexity and predicts morbidity and mortality to guide decision making between coronary artery bypass graft surgery and percutaneous coronary intervention in patients with acute coronary syndrome. The present study aimed to compare nitric oxide levels with the SYN-TAX score in terms of predicting coronary complexity and the treatment decision for unstable angina pectoris in the emergency department. Methods: The study included 120 patients with unstable angina pectoris and 120 control group subjects. Nitric oxide levels were compared with the SYNTAX score and the treatment decision. The UAP group was divided into 2 subgroups, first based on SYNTAX score of <= 18, >18-27 or >27 and then on the treatment decision of coronary angiography, percutaneous coronary intervention, or coronary artery bypass graft surgery. Results: The mean nitric oxide levels in the unstable angina pectoris group were lower than in the control group (P < 0.001). Nitric oxide levels were negatively correlated with the SYNTAX score and the treatment decision (r = -0.227, P = 0.013; r = -0.498, P < 0.001, respectively). The nitric oxide levels were decreased with SYNTAX score >27 compared with >18-27 and = 18 (P = 0.04-0.003, respectively). Nitric oxide levels were decreased in coronary artery bypass graft surgery subgroup compared with the coronary angiography and percutaneous coronary intervention groups (P < 0.001-0.018 and P < 0.001, respectively). Conclusions: Nitric oxide may be considered as a novel biomarker in the prediction of coronary complexity in patients with unstable angina pectoris.