Multivessel coronary artery disease: A key predictor of short-term prognosis after reperfusion therapy for acute myocardial infarction

Abstract

Results of recent studies have suggested that routine cardiac catheterization may be unnecessary after reperfusion therapy for acute myocardial infarction. Therefore to better define the short-term prognostic value of early coronary angiography, and specifically the prognostic significance of multivessel coronary artery disease, the angiographic findings of 855 patients consecutively enrolled in five phases of the TAMI study were correlated with their in-hospital outcome. All patients received intravenous thrombolytic therapy (tissue plasminogen activator, urokinase, or both agents) and underwent cardiac catheterization within 90 minutes of the initiation of therapy. Multivessel disease, defined as the presence of ≥ 75% luminal diameter stenosis in two or more major epicardial arteries, was documented in 236 patients. When compared with the group of patients without multivessel disease, this group had a higher prevalence of coronary risk factors and more frequently had a history of antecedent ischemic chest pain. Although the severity of the infarct zone dysfunction was similar in the two groups (−2.77 ± 1.00 vs −2.50 ± 1.09 SD/chord, p = NS), global left ventricular ejection fraction was lower in the group with multivessel disease (48.6 ± 12.4% vs 51.8 ± 10.6%, p < 0.01). This was associated with a significant difference in the function of the noninfarct zone. Whereas this region was hyperkinetic in the group with minimal or single-vessel disease, it was hypocontractile or dyskinetic in those with multivessel disease (+0.66 ± 1.53 vs −0.52 ± 1.73 SD/chord, p = 0.0001). The in-hospital mortality rate, predominantly the result of myocardial failure and cardiogenic shock, was also significantly higher in the multivessel group (11.4% vs 4.2%, p < 0.0001). By means of data from the 708 patients enrolled in the first three TAMI studies, a statistical model was developed to describe the determinants of in-hospital survival. By logistic regression analysis the strongest independent predictor of in-hospital mortality was the number of diseased vessels ( p < 0.002). Other parameters that contributed significantly included global left ventricular ejection fraction ( p = 0.01), TIMI grade infarct vessel flow ( p = 0.03), and patient age ( p = 0.03). According to this model the prognostic significance of one additional year of age was equivalent to a reduction in left ventricular function of 1.1 ejection fraction percentage points; one additional diseased vessel was equivalent to 15 additional years of age or a reduction in ejection fraction of 16 percentage points. These data suggest that more aggressive revascularization procedures should be considered in the early postinfarction period for patients with multivessel disease and noninfarct zone dysfunction. In the absence of reliable noninvasive techniques, coronary angiography remains the procedure of choice for identifying this high-risk subgroup.