Prognostic significance from 10-year follow-up of a qualitatively normal planar exercise thallium test in suspected coronary artery disease.

A normal exercise thallium-201 scintigram has been shown to confer an excellent prognosis over a 1- to 4-year follow-up period. However, progression of coronary disease could result in cardiovascular mortality with increasing time. Therefore, the vital status of 309 patients with normal stress thallium myocardial imaging was determined after an average of 10.3 years. Deaths were classified as cardiac or noncardiac. Statistical analysis was performed using Kaplan-Meier survival curves. Standardized mortality ratios were calculated and compared with those of an age- and sex-matched general population. Follow-up was complete in 288 patients (93%). Of 18 deaths, only 3 were cardiac; the remaining 15 were mainly secondary to cancer. Thus, cardiac mortality was 1% and total mortality 6.3% at 10 years. In addition, both all-cause and cardiac mortality rates were significantly less than would be expected in an age- and sex-adjusted segment of the general population. Thus, normal exercise thallium scintigraphy retains its high negative predictive value for death < or = 10 years after initial testing. This supports the use of stress thallium imaging to predict which patients with suspected coronary artery disease are at low risk for cardiac death and thus do not need invasive testing.

Bypass surgery for chronic stable angina: predictors of survival benefit and strategy for patient selection.

The variable mortality risk associated with chronic stable angina calls for careful selection of patients for coronary artery bypass grafting (CABG) if the aim of management is to prolong life. The randomized and observational studies done in the last 20 years have identified the variables relevant to patient selection and thus have provided a rational basis for such clinical decisions. These studies showed that the sicker the patient, as gauged by relevant measures of coronary disease and cardiovascular morbidity, the more likely it is that CABG will prolong life. A CABG-related improvement in survival is therefore more likely to occur the worse the left ventricular function; the greater the number of diseased vessels; the more proximal the location of coronary lesions (more muscle is threatened by such lesions); the greater the severity of the lesions as determined by angiography; the more severe the angina; the more easily provocable the ischemia or the more extreme the measures of ischemia; and, within limits, the older the patient. Greater survival gain after CABG also occurs in patients with peripheral vascular disease, in patients with baseline electrocardiographic ST-segment and T-wave changes, and probably in women. Thus, patients are likely to live longer after CABG if they have left main disease; three-vessel disease with left ventricular dysfunction (ejection fraction less than 50%), class III or IV angina, provocable ischemia, or disease in the proximal left anterior descending coronary artery; two-vessel disease with proximal left anterior descending artery involvement; and two-vessel disease with class III or IV angina as well as either severe left ventricular dysfunction alone or moderate left ventricular dysfunction together with at least one proximal lesion. When the decision of whether to do CABG is less clear-cut, the presence of peripheral vascular disease, female sex, baseline electrocardiographic ST-segment and T-wave changes, or older age (over 60 but under 80 years) should weigh in favor of doing CABG. In general, patients with single-vessel disease do not seem to derive survival benefit from CABG.

Role of exercise thallium-201 myocardial perfusion scintigraphy in predicting prognosis in suspected coronary artery disease.

While exercise thallium imaging has improved sensitivity and specificity for detection of coronary artery disease (CAD), its predictive value for morbid cardiac events is unclear. Of 532 consecutive patients who underwent exercise thallium imaging, follow-up was complete in 515 (97%) after an average of 36 months (range 31 to 48). Two hundred six patients had an abnormal exercise thallium response and 309 had a normal response. Twenty morbid cardiac events occurred (13 deaths and 7 acute myocardial infarctions [AMI]). Of the 13 patients who died, 12 had abnormal thallium results. Overall, 5.8% of the patients with abnormal thallium results died, in contrast to 0.3% of patients with normal results. Of the 7 patients who had a nonfatal AMI, 3 had abnormal exercise thallium results. Moreover, similar proportions of patients (1.4% and 1.3%) with normal and abnormal exercise thallium results had nonfatal AMI. Presence or absence of pathologic Q waves and inclusion of exercise electrocardiographic results did not significantly alter the results. Thus, although a normal exercise thallium response significantly reduces the likelihood of cardiovascular death, its predictive value for nonfatal AMI is limited. Moreover, the relatively low event rate for patients with a positive exercise thallium response further limits its prognostic value.