Cardiac disease severity: The degree and distribution of stenoses measured by coronary angiography, findings on exercise testing and stress imaging, and LV function measured with a variety of technologies all provide meaningful prognostic information that supplements more clinical information. 3.1.2. Risk Assessment Using Clinical Parameters Although there are several models to predict the likelihood of complications and survival in asymptomatic, general popula- tions and in patients with ACS, there is a relative paucity of information about models for assessing the risk of patients with known SIHD that incorporate a broad range of relevant data. Accurate risk assessment according to clinical variables is essential to determining optimal treatment strategies. Lauer and colleagues developed a risk index that incorporates variables from the history and exercise test on the basis of data from .32 000 individuals.248 They found that their index, which can be calculated by using a nomogram (Figure 8), was better able to predict individuals with a low (,3%) risk of death than was the Duke treadmill score. Daly and colleagues reported an index to estimate risk of death or nonfatal AMI derived from data on an international sample of approximately 3000 patients who presented with angina and were followed up for 18 months (Figures 9 and 10). Obstruc- tive CAD was documented in one third, whereas another third had negative evaluations. The c statistic for the model was 0.74, which indicates a relatively high level of accuracy.57 Several risk-assessment schemes have been developed to assist in identifying patients with severe CAD, including left main disease, although several of these studies are up to 2 decades old. 