Background: Statins exert a variety of favourable effects on the vascular system not directly related to their lipid lowering function known as pleiotropic effects. There are not enough data regarding the effects of prior statin use on coronary blood flow after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Accordingly, in the present study, we aimed to investigate the effects of prior statin use on coronary blood flow after primary PCI in patients with AMI using the Thrombolysis In Myocardial Infarction (TIMI) frame count method.
Methods: The study population consisted of 200 patients (161 men; mean age=62+/-7 years) referred to cardiology clinics with AMI who subsequently underwent successful primary PCI. The study population was divided into two groups according to statin use before primary PCI. Group 1 consisted of 98 patients (75 men; mean age=63+/-7 years) not taking statin and group 2 consisted of 102 patients (86 men; mean age=61+/-7 years) taking daily dose of at least 40 mg atorvastatin for at least 6 months. Coronary blood flow was determined by TIMI frame count method using the angiographic images obtained just after PCI and stenting.
Results: Only mean TIMI frame count was detected to be significantly lower in patients taking at least 40 mg atorvastatin for at least 6 months compared with that of the patients taking no statin (P<0.001). After confounding variables were controlled for, the mean TIMI frame count of patients in group 2 was significantly lower than that of the patients in group 1 (P=0.001). Pain to balloon time and vessel type were detected as important confounding variables of TIMI frame count after analysis of covariances.
Conclusions: Prior statin use may improve coronary blood flow after PCI in patients with AMI, possibly by its beneficial effects on microvascular function.