A prior myocardial infarction: how does it affect management and outcomes in recurrent acute coronary syndromes?

BACKGROUND: Despite improved secondary prevention efforts, acute coronary syndrome (ACS) recurrence among patients with prior history of coronary events remains high. The differences in presentation, management, and subsequent clinical outcomes in patients with and without a prior myocardial infarction (MI) and presenting with another episode of ACS remain unexplored. METHODS: A total of 3,624 consecutive patients admitted to the University of Michigan with ACS from January 1999 to June 2006 were studied retrospectively. In-hospital management, outcomes, and postdischarge outcomes such as death, stroke, and reinfarction in patients with and without a prior MI were compared. RESULTS: Patients with a prior MI were more likely to be older and have a higher incidence of diabetes mellitus, hypertension, hyperlipidemia, and peripheral vascular disease. In-hospital outcomes were not significantly different in the 2 groups, except for a higher incidence of cardiac arrest (4.3% versus 2.5%, p < 0.01) and cardiogenic shock (5.7% versus 3.9%, p = 0.01) among patients without a prior MI. However, at 6 mo postdischarge, the incidences of death (8.0% versus 4.5%, p < 0.0001) and recurrent MI (10.0% versus 5.1%, p < 0.0001) were significantly higher in patients with a prior history of MI compared with those without. CONCLUSION: Patients with prior MI with recurrent ACS remain at a higher risk of major adverse events on follow-up. This may be partly explained by the patients not being on optimal medications at presentation, as well as disease progression. Increased efforts must be directed at prevention of recurrent ACS, as well as further risk stratification of these patients to improve their overall outcomes.

Role of PPAR- gamma agonist thiazolidinediones in treatment of pre-diabetic and diabetic individuals: a cardiovascular perspective.

The peroxisome proliferator-activated receptors (PPARs) are nuclear fatty acid receptors, which contain a type II zinc finger DNA binding motif and a hydrophobic ligand binding pocket. These receptors are thought to play an important role in metabolic diseases such as obesity, insulin resistance, and coronary artery disease. Three subtypes of PPAR receptors have been described: PPARalpha, PPARdelta/beta, and PPARgamma. PPARalpha is found in the liver, muscle, kidney, and heart. In the liver, its role is to up-regulate genes involved in fatty acid uptake (beta-oxidation and omega-oxidation). PPARdelta/beta is involved in fatty acid oxidation in muscle. PPARgamma has high expression in fat, low expression in the liver, and very low expression in the muscle. The thiazolidinediones (TZD) are synthetic ligands of PPARgamma. By activating a number of genes in tissues, PPARgamma increases glucose and lipid uptake, increases glucose oxidation, decreases free fatty acid concentration, and decreases insulin resistance. There is a sound rationale for the use of TZDs in patients with type 2 diabetes mellitus and promising preliminary data in patients with patients with pre-diabetes. In patients with type 2 diabetes, thiazolidinediones had been shown to decrease mean HbA(1c)by 1.5% and lower HbA(1c) to less than 7% in 30% of patients. Decreased muscle insulin resistance primarily mediates the glucose lowering effect. In addition, there are several nonhypoglycemic effects of TZDs which may be beneficial to both diabetics and patients with pre-diabetes. These include effects on lipid metabolism, blood pressure, endothelial function, atherosclerotic plaque, coagulation, and albuminuria. In a pilot study, we recently demonstrated that insulin sensitizers such as thiazolidinediones appear to be associated with better clinical outcomes compared to insulin providers in diabetic patients presenting with acute coronary syndromes. In another study, we showed that the prediabetic state is a marker for worse prognosis in patients with acute coronary syndromes. In this article, we review the existing literature on the effectiveness of PPAR-gamma agonists in patients with either overt diabetes or a prediabetic state.