Smoking and Activated Clotting Time during coronary angiography and angioplasty: protocol for the ACT-Tobacco trial.

Background: During percutaneous transluminal coronary angioplasty (PTCA), activated clotting time (ACT) measurements are recommended to attest a correct anticoagulation level and, if needed, to administer further unfractionated heparin (UFH) to obtain a therapeutic ACT value. Our clinical routine led us to observe that smokers had lower ACT values after standardized UFH administration during PTCA. Procoagulant status in smokers is well documented. Objectives: To determine whether tobacco negatively affects UFH anticoagulation during PTCA when evaluated by ACT. Methods: The ACT-TOBACCO trial is a single-center, noninterventional, prospective study. The primary end point is the comparison of ACT values after standardized UFH administration between active smokers and nonsmokers (active smoker group vs nonsmoker group) requiring coronary angiography followed by PTCA. The main secondary end points include ACT comparison after the first and second standardized UFH administration according to the patient's smoking status (active, ex-, or nonsmoker) and the clinical presentation of ischemic cardiomyopathy: stable (silent ischemia or stable angina) or unstable (unstable angina or acute coronary syndrome without or with ST-segment elevation). Conclusions: To the best of our knowledge, ACT values during PTCA between smokers and nonsmokers have not previously been compared. As current PTCA procedures increase in complexity and duration, the understanding of procoagulant risk factors such as smoking and the need for reliable anticoagulation monitoring becomes essential to balance hemorrhagic risk against thrombotic risk.