Outside of such special circumstances, routine periodic testing is not recommended in patients who are at low risk for progression or had overt symptoms on initial presentation (ie, those without known silent ischemia) or very early after revascularization. In addition to a lack of evidence for testing to detect ischemia, currently there is also little research to support exercise stress testing for risk assessment in asymp- tomatic patients with known CAD, except for cardiac reha- bilitation and exercise prescription purposes (Section 4.4.1.4.). 6.3.4. Patient Risk and Testing By using clinical, noninvasive, and invasive data acquired during the initial evaluation and subsequently, recommenda- tions about stress testing in patients with known SIHD can be formulated on the basis of the following considerations: In the absence of a change in clinical status, patients with a low projected annual mortality rate (,1%) are those with low-risk Duke treadmill scores, either without imaging or with nega- tive imaging findings, whose 4-year cardiovascular survival rate approximates 99%. The low-risk category also includes patients with normal stress imaging who lack adverse prog- nostic characteristics, such as diabetes mellitus or prior MI. Younger women without diabetes mellitus or a prior MI who have normal stress nuclear MPI remain at very low risk for as long as 7 to 9 years,307 depending on specific clinical characteristics, and probably do not require repeat stress imaging during that period in the absence of changes in Data are more limited with regard to the value of serial testing strategies in patients at intermediate risk of cardiac mortality (1% to 3% per year). Follow-up testing probably should be performed only if decisions about a change in pharmacological management, level of exercise, or revascu- larization will be influenced directly by the test result or if the patient has persistent symptoms despite adequate GDMT. 