CardioExchange Archive

Circadian patterns have long been known to influence the cardiovascular system, resulting in early morning peaks in blood pressure, heart rate, and certain hormone levels, as well as an increased risk for MI and sudden cardiac death. Now, in a study published in JACC: Cardiovascular Interventions, Karim Mahmoud and colleagues have found that coronary stent thrombosis is more likely to take place in the early morning hours. Using the Mayo Clinic Percutaneous Coronary Intervention Registry, the team identified 124 patients with definite stent thrombosis and a known date and time of symptom onset.

Peak incidence for stent thrombosis occurred at 7 AM; the association was significant only in the 49 patients with early (0 to 30 days) stent thrombosis, not in those with late or very late stent thrombosis. The researchers found no association with the day of week, but did observe a higher incidence of stent thrombosis in the summer, which they speculated may have been related to increased activity.

“The most practical implication of these study results is that it may be of benefit for patients with coronary stents to take their antithrombotic medication in the evening (rather than in the morning) to prevent nadir levels of medication during the hazardous morning hours,” said Mahmoud, in an ACC press release.