Primary percutaneous coronary intervention vs conservative treatment for acute ST elevation myocardial infarction: short- and long-term follow-up according to disease severity.

BACKGROUND: Because there is insufficient evidence to support primary percutaneous coronary intervention (PPCI) as the treatment of acute myocardial infarction (AMI), this study elucidated the efficacy of PPCI according to disease severity. METHODS AND
RESULTS: Between January 1999 and June 2001, 3,021 AMI patients were registered at Tokyo Women's Medical University and 17 affiliated institutions. Of these, 1,994 patients with ST-elevation AMI were admitted within 12 h of onset. PPCI was performed in 1,143 and 294 were treated conservatively. The 1,437 patients were grouped according to Thrombolysis In Myocardial Infarction-risk score: PPCI was performed in 59.5% of the low-risk group, 61.8% of the moderate-risk group, and 56.2% of the high-risk group. Cardiac death was the primary outcome. In the low-risk group, no significant differences were observed between PPCI and conservative therapy for 30-day and long-term cardiac mortality rates. In the moderate-risk group, the 30-day cardiac mortality rate for PPCI was significantly lower; however, no significant intergroup differences were observed for long-term cardiac mortality. In the high-risk group, 30-day and long-term cardiac mortality for PPCI were significantly more favourable than for conservative therapy (p<0.001 and p=0.0032, respectively).
CONCLUSIONS: Although PPCI strongly correlated with low short- and long-term cardiac mortality rates in high-risk AMI patients, no similar correlation was found in low-risk patients.