Assessment of therapeutic effects of statin on cardiac sympathetic nerve activity and cardiac events in patients with ischemic cardiomyopathy and mild to moderate heart failure.

Abstract

We determined whether statin therapy improved cardiac sympathetic nerve activity as evaluated using iodine-123-metaiodobenzylguanidine (I-MIBG) scintigraphy, and whether this therapy affects prognosis in patients with ischemic cardiomyopathy. This study was a subanalysis of our previous report of the result that the serial I-MIBG scintigraphic studies were the most useful prognostic indicator in patients with heart failure. Patients with heart failure [left ventricular ejection fraction (LVEF) <45%] but no cardiac events for at least 5 months before the study were identified according to their history of decompensated acute heart failure requiring hospitalization. The patients underwent I-MIBG scintigraphy and echocardiography immediately before hospital discharge and after 6 months. The % denervation, heart/mediastinum count ratio, and washout rate were determined from the I-MIBG scintigraphy, and the left ventricular end-diastolic volume, left ventricular end-systolic volume, and LVEF were also determined from echocardiography. We selected 76 patients with old myocardial infarction without active ischemia and used propensity score matching to compare patients who received oral statin (n=38) with those who did not (n=38). The patients were followed up for a median of 4.74 years, with the primary and secondary study end points defined as incidences of fatal cardiac events and major adverse cardiac events (MACEs), respectively. After treatment, the I-MIBG scintigraphic and echocardiographic parameters were improved in the statin and nonstatin groups. However, the extent of change in the % denervation was -12.3±10.3 and -6.2±9.6 (P<0.01), whereas that in the heart/mediastinum count ratio was 0.19±0.14 and 0.08±0.15 (P<0.01), and that in washout rate was -8.1±7.2 and -0.5±9.2% (P<0.01). The extent of change in left ventricular end-diastolic volume, left ventricular end-systolic volume, and LVEF in the statin group tended to exceed than in the nonstatin group, but these changes were not statistically significant. Of the 76 patients, 18 experienced fatal cardiac events and 32 experienced MACEs during the study. Multivariate Cox regression analyses revealed that the nonstatin therapy was a significant predictor of both cardiac death and MACEs in our patients. On Kaplan-Meier analysis, the rates of freedom from cardiac death or MACEs were significantly higher in the statin group than those in the nonstatin group (all, P<0.05). Statin therapy improved cardiac sympathetic nerve activity in patients with ischemic cardiomyopathy and mild to moderate heart failure. Furthermore, statin is potentially effective for reducing cardiac events in these patients.