Abstract 321: Synergistic Effect of Coronary Artery Disease Risk Factors on Long-term Survival in Patients Without Cardiac Disease and a Normal Treadmill Stress SPECT
Background: Normal exercise single photon emission computed tomography (SPECT) studies are associated with a low event rate during short-term follow-up, but the influence of cardiac risk factors on long-term outcomes in such patients is not well studied.
Methods: 1,924 patients (56±12 yrs, male 40%) without a history of coronary artery disease (CAD) and a normal exercise SPECT between the years 1995–2003 were retrospectively assessed for all-cause mortality during a mean follow up of 8±3yrs as a function of baseline recorded CAD risk factors.
Results: 536 (28%) patients had no risk factors, 922 (48%) had one risk factor and 466 (24%) had ≥2 risk factors. There were 116 (6%) deaths among all patients (event rate 1%/year). Univariate analysis revealed that hypertension (RR= 1.6 95% CI 1.08–2.40, p= 0.02), diabetes (RR= 1.7, 95% CI 1.11–2.57, p= 0.01), and smoking (RR= 1.6, 95% CI 1.707–2.4, p= 0.02) were each associated with worse survival. Multivariate analysis revealed that the presence of ≥2 CAD risk factors was associated with increased mortality (HR = 2.2 95% CI 1.5–4.7, p<0.0001). The Kaplan-Meier curve for survival is shown (Graph).
Conclusion: While the long-term risk of CAD remains relatively low among non-ischemic exercising patients with even multiple CAD risk factors, there is still a progressive incremental risk in long-term outcome with increasing number of CAD risk factors.