When ticagrelor should be discontinued prior to elective surgery is unclear. The risks of bleeding when it is continued peri-operatively have to be weighed against the risk of coronary artery thrombosis when stopped. This study aims to assess coagulation and thrombocyte function every other day in patients who are taking ticagrelor after coronary artery stents and discontinue therapy at the end of one year.

Patients who have an acute coronary syndrome are today often treated by percutaneous coronary intervention (PCI) and insertion of one or several coronary stents. Subsequently, these patients are treated with oral anti-platelet (OAP) drugs, usually a combination of acetyl salicylic acid (aspirin) and clopidogrel/ticagrelor. Although aspirin is continued for a life-long period, clopidogrel/ticagrelor are used for a variable period of time, often from 3 months - 1 year after PCI, depending on the type of stent. Interventional elective non-cardiac surgery during the time of clopidogrel/ticagrelor therapy is not recommended except for life-threatening (acute surgery) or life-prolonging (cancer surgery) procedures. Specifically for life-prolonging procedures, surgery can be planned, and therefore the question often arises as to when OAPs should be terminated prior to planned surgery. This decision rests on balancing the risks of bleeding (when continued) or coronary stent thrombosis (when stopped). Certainly, because of the small risk of severe bleeding when using aspirin, this drug should be continued throughout the perioperative period in patients with coronary stents. However, continuing clopidogrel/ticagrelor is more controversial since severe perioperative bleeding is difficult to reverse in these patients. Therefore, surgeons would normally discontinue clopidogrel/ticagrelor prior to surgery, specifically when the potential for bleeding is high, and the consequences major. The exact duration for which these drugs should be discontinued remains unclear and, depending on the drug used, a period of 3 - 5 days is generally recommended, based on the pharmacokinetics and dynamics of clopidogrel/ticagrelor in otherwise healthy patients.

This study was done to better understand coagulation and thrombocyte function immediately before discontinuation of ticagrelor and at regular intervals after termination, in patients who have previously undergone PCI, have coronary stents, are taking ticagrelor but discontinue it after one-year of therapy in accordance with hospital routines. No surgical intervention was planned in these patients after termination of ticagrelor.

Inclusion Criteria:

- Patients who are on the Cardiology Clinic's database at the University Hospital, Örebro and shall terminate ticagrelor after one year following PCI and stent placement would be identified and offered to take part in this study.

Exclusion Criteria:

- Non-responders (not partial responders) to ticagrelor would be excluded from the study. Additionally, patients who are either taking NSAID's regularly or during the last 2 weeks prior to study start would also be excluded as those who have language or cognitive limitations.

Patients who have previously had a coronary artery syndrome treated by PCI and stent placement and who are taking the oral anti platelet drugs aspirin and ticagrelor would be included into the study.