Abstract 12428: Risk Stratification of Asymptomatic Patients Post Revascularization Using the Bethesda Score

Abstract

Background. Functional testing is of indeterminate appropriateness in asymptomatic pts post revascularization (RVS). The Bethesda Score (BS) integrates information from history and physical examination for the prediction of the risk of death. We sought the use of this score to risk stratify asymptomatic post RVS pts and potentially select pts for testing.

Methods. We studied 1903 asymptomatic pts (age 64±10 y; 273 [14%] women, 760 [40%] past myocardial infarction) at 4.1±4.7 y after RVS (1042 [55%] had PCI and 861 [45%] had CABG). Pts were followed for 5.7±3.0 y for mortality. BS was divided into tertiles and association with survival was assessed using Cox regression. The incremental value of exercise capacity (EC) and then stress echocardiography (SE) was evaluated using nested models. Results. The mean BS was 115(±29), 14% had poor EC (≤ 6Mets) and 13% had ischemia on their SE. During follow-up, 182 (9.6%) pts died. In a multivariate Cox regression (Fig 1), the lowest tertile of BS (<100) identified pts at low risk of death (≤1% per year). Normal EC (METs>6) was independent of (H.R. 3.1; 95% C.I. (2.2-4.3), p=0.000) and incremental to the BS (-2 log Likelihood chi-square difference of 80, df=1, p=0.000) and was able to further risk stratify patients after exclusion of the low BS tertile group. Similarly, and after exclusion of this low risk group, a positive SE for ischemia was independent of (H.R. 0.6; 95% C.I. (0.4-0.9), p=0.01) and incremental to both the BS and the EC (-2 log Likelihood chi-square difference of 6.75, df=1, p=0.01), however it failed to further risk stratify patients after exclusion of the normal EC group. Conclusions. Asymptomatic patients after coronary RVS may be risk stratified using the BS and then the EC in selected patients with high BS (≥100). While SE is predictive, it doesn’t help in further risk stratification. Appropriateness of functional imaging in asymptomatic patients post revascularization must be carefully reviewed.