Patients, male or female, over 18 years of age, who are either known to have experienced late or very late drug-eluting stent thrombosis (Case), or have undergone drug-eluting stent implantation at the same facility, in the same time period as a matched Case Subject, and have not experienced drug-eluting stent thrombosis (Control).

Inclusion Criteria:

• Patients over 18 years of age
• Case Subjects: patients who have experienced definite late or very late drug-eluting stent thrombosis
• Control Subjects: patients who underwent drug-eluting stent implantation at the same facility and in the same time period as a matched Case Subject, and have not experienced drug-eluting stent thrombosis.

Exclusion Criteria:

• Patients not meeting the above Inclusion Criteria