Circadian variation in coronary stent thrombosis.

OBJECTIVES We sought to determine the circadian, weekly, and seasonal variation of coronary stent thrombosis. BACKGROUND Other adverse cardiovascular events such as acute myocardial infarction are known to have higher incidences during the early morning hours, Mondays, and winter months. METHODS The Mayo Clinic Percutaneous Coronary Intervention Registry was searched for patients admitted to our center who underwent repeat percutaneous coronary intervention in a previously stented coronary artery segment. Stent thrombosis was confirmed by angiographic review, and date and time of symptom onset were obtained from medical records. RESULTS We identified 124 patients with definite stent thrombosis and known date and time of symptom onset. In these patients, onset of stent thrombosis was significantly associated with time of day (p = 0.006), with a peak incidence around 7:00 am. When patients were subdivided into early stent thrombosis (0 to 30 days; n = 49), late stent thrombosis (31 to 360 days; n = 30), and very late stent thrombosis (>360 days; n = 45), only early stent thrombosis remained significantly associated with time of day (p = 0.030). No association with the day of the week was found (p = 0.509); however, onset of stent thrombosis did follow a significant seasonal pattern, with higher occurrences in the summer (p = 0.036). CONCLUSIONS Coronary stent thrombosis occurs more often in the early morning hours. Early stent thrombosis follows a circadian rhythm with a peak at 7:00 am. This pattern was not significant in late and very late stent thrombosis. Occurrences throughout the week were equally distributed, but stent thrombosis was more likely to occur in the summer months.