1. Department of Cardiovascular Medicine; National Cerebral and Cardiovascular Center; 5-7-1 Fujishiro-dai, Suita Osaka 565-8565 Japan
2. Department of Cardiovascular Surgery; National Cerebral and Cardiovascular Center; Suita Osaka Japan
3. Department of Pathology; National Cerebral and Cardiovascular Center; Suita Osaka Japan
4. Department of Cardiovascular Medicine; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan