A normal dobutamine echocardiogram is associated with a risk of an adverse cardiac event of 1% to 2%.312,334 Classification as high risk by dobutamine stress echocardiography is most reliable when ischemia is detected in the territory of the LAD and is somewhat less reliable in patients with diabetes mellitus.335 In specialized centers, either quantification of strain rate or myocardial contrast enhancement on dobuta- mine echocardiography has been shown to provide informa- tion that supplements the wall motion score alone in predict- ing cardiac mortality.336 Dobutamine echocardiography also has been used extensively in risk-stratifying patients with SIHD undergoing noncardiac vascular surgery. Because the risk of a cardiac event in the perioperative period is quite low, the positive predictive value of dobutamine echocardiography is also low, although the negative predictive value of a normal result is very high and is associated with a very low likelihood of a perioperative event.337,338 Similar to exercise SPECT, vasodilator stress nuclear MPI has been shown to effectively assess risk of subsequent events in patients with SIHD, with a low annualized event rate of 1.6% observed in patients with a normal adenosine SPECT versus 10.6% in patients with a severely abnormal study (summed stress score .13).339 This event rate also was observed in elderly patients with normal pharmacological SPECT.340,341 Because of greater comorbidity in patients who cannot exercise, the annualized event rate of patients who had a normal pharmacological stress nuclear MPI increase the event rate nearly 2-fold higher than that of exercising patients who had a normal nuclear MPI, after adjustment for age and comorbidity.342 Additional nonperfusion risk markers can be derived from pharmacological stress, including an abnormal ECG, high resting heart rate, and low peak/rest heart rate ratio.276,332 To facilitate clinical risk assessment, a nomogram based on robust risk markers, including LV function and extent of myocardial ischemia by SPECT, has been devel- oped and validated (Appendix 4).276 3.2.2.7. 