Abstract 1434: Simvastatin Preserves Myocardial Function After Coronary Microembolisation in Rabbits
Coronary microembolisation (CME) frequently occurs during spontanous coronary plaque rupture and coronary angioplasty. In experimental studies, CME induces a pronounced inflammatory response that decreases contractile function of embolized myocardium for several days. Since statins exert anti-inflammatory effects, we tested whether simvastatin (Sim) would preserve left ventricular (LV) function after CME. In anaesthetized rabbits (n=24, 3.4±0.2 kg), polysterol microspheres (45 μM diameter, n=10.000–30.000) were infused into the left main coronary artery via a 3 F catheter during flouroscopy. Animals received Sim (3 mg/kg/day p.o., n=10) or placebo (P, n=14) from 3 days before until 9 days after CME. Three animals treated with P but none treated with Sim died within 24 h after CME. Troponin T increased to a similar extent at 1 day after CME (P 3.5±1.1, Sim 3.5±1.0 ng/ml). In P, LV shortening fraction (SF, echocardiography, short-axis view at papillary level) was decreased at day 2 after CME (32±2 vs 40±1%, p<0.05) but was preserved in Sim (40±2 vs 41±1%). There was a linear relationship between SF and troponin T in P that was shifted upwards in Sim (figure⇓). SF recovered completely at 9 days after CME (P 43±2%, Sim 41±2%). At 2 days after CME, Sim also significantly attenuated LV dilation and preserved LV ejection fraction. LV myocardial fibrosis was not different between P and Sim at 9 days after CME (15,3±1,5 vs 14,2±1,4 %, picrosirius red). We conclude that CME induces a transient, inflammatory phase of myocardial dysfunction that can effectively be prevented by simvastatin. These data support the immediate use of statins during acute coronary syndromes.