Abstract 574: Impact of Long-Term Statin Pretreatment on the Incidence of Plaque Rupture and Infarct Size in ST-Elevation Acute Myocardial Infarction
Background: Statins have been shown to stabilize atheromatous plaques by increasing fibrous-cap thickness in experimental animals, which may help to prevent plaque rupture. However, whether statin treatment in humans reduces plaque rupture remains unknown. Several studies reported that the presence of plaque rupture in ST-elevation myocardial infarction (STEMI) is associated with larger infarct size. Thus, we hypothesized that statin treatment before the onset of STEMI is associated with lower incidence of plaque rupture detected by intravascular ultrasound (IVUS), resulting in smaller infarct size.
Methods: IVUS interrogation was performed prior to percutaneous coronary intervention in 355 patients (295 men) with STEMI who were admitted within 6 hours from onset.
Results: Plaque ruptures were detected in 217 patients (61%). Patients with statin pretreatment (n=52, 15%) had a lower incidence of plaque rupture than those without (40 vs 65 %, p=0.002). Univariate analysis showed that smoking (p=0.001), lower high-density lipoprotein (p<0.001), and a lack of statin pretreatment (p=0.002) correlated with a higher incidence of plaque rupture. Multiple logistic regression analysis revealed that statin pretreatment was a negative determinant of plaque rupture (odds ratio 0.4, p=0.009), independent of age, sex, and other risk factors including low-density lipoprotein cholesterol level. Patients with plaque rupture had larger infarct size as assessed by peak creatine kinase-MB (CK-MB) than those without (192 vs 143 IU/L, p=0.01), whereas patients with statin pretreatment had smaller infarct size than those without (115 vs 179 IU/L, p=0.03). Statin pretreatment was a determinant of smaller infarct size (CK-MB < median value) independent of the reperfusion time and location of culprit lesion (odds ratio 2.0, p=0.04). Among patients with plaque rupture, infarct size were similar between patients with and without statin pretreatment (237 vs 246 IU/L, p=0.9).
Conclusions: Long-term statin pretreatment is associated with lower incidence of plaque rupture and smaller infarct size in STEMI, indicating that prevention of plaque rupture by statins may confer cardiovascular protection including smaller infarct size even in patients who developed STEMI.