Procedural success versus clinical risk status in determining discharge of patients after primary angioplasty for acute myocardial infarction

Abstract

We evaluated whether patients' clinical status, angioplasty success, or both, should guide discharge after primary angioplasty (i.e., percutaneous coronary intervention [PCI]) for acute myocardial infarction (AMI). Current guidelines do not address a discharge strategy for AMI patients undergoing successful PCI. Patients who underwent PCI in Primary Angioplasty in Myocardial Infarction (PAMI) studies (N = 3,188) were classified as "high clinical risk" if they had either age >70 years, Killip class >1, heart rate >100 beats/min, systolic blood pressure <100 mm Hg, anterior MI, or left bundle branch block, and as "low clinical risk" if none was present. Successful PCI patients were compared with those with unsuccessful PCI in both groups for 30-day major adverse cardiac events (MACE). Percutaneous coronary intervention was successful in 668 (90%) of 745 low-risk clinical and 2,104 (86%) of 2,443 high-risk clinical patients. Regardless of clinical risk status, patients with successful PCI had lower 30-day MACE than those with unsuccessful PCI (low-risk group: 4.6% vs. 22%, p < 0.0001; high-risk group: 7% vs. 21%; p < 0.0001). Moreover, successful PCI patients with either risk status had few MACE after day 4, whereas unsuccessful PCI patients had more MACE. The success of PCI was the strongest independent predictor of 30-day MACE (odds ratio [OR] 3.7, 95% confidence interval [CI] 2.8 to 5.0). A constellation of three or more high-risk clinical features also predicted higher 30-day MACE (OR 2.25, 95% CI 1.62 to 3.12). The success of PCI is the prime determinant of clinical outcome after PCI for AMI. The majority of AMI patients with less than three high-risk clinical features who undergo successful PCI may be discharged from the hospital by day 4. In contrast, patients with more than two high-risk clinical features or unsuccessful PCI may need longer observation.