Assessment of Coagulation and Thrombocyte Function After Termination of Ticagrelor
Condition: PCI; Coronary Stents
Study type: Observational

Summary: 
      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.
    

Detailed description: 
      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.
    

Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        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.
      
Biospecimen description: 
      Blood for analysis of complement, coagulation factors and other biochemical markers