Detection of myocardial ischemia in the elderly versus the young by stress thallium-201 scintigraphy and its relation to important coronary artery disease

The prevalence and severity of coronary atherosclerosis increase dramatically with age, so that more than half of all deaths in persons aged over 65 are due to coronary arterial disease (CAD) and about three fourths of all deaths from CAD occur in the elderly. The aims of our study were, first, to detect myocardial ischemia development in elderly versus younger patients undergoing treatment for known CAD through the use of both conventional treadmill testing and 201Tl scintigraphy, and second, to determine the relationship between the above non-invasive tests and angiographically confirmed important coronary artery disease (iCAD). A database of 606 patients (355 men and 251 women) who had undergone coronary angiography, exercise ECG testing (ETT) using the treadmill Bruce protocol, and 201Tl scintigraphy, was reviewed retrospectively. All patients had displayed clinical expression of CAD with or without the existence of an old myocardial infarction (MI). The patients were from both sexes (440 men and 252 women) and divided into two groups, according to age. Group A was composed of 265 patients aged over 65 (170 men, 95 women, mean age = 70.3 ± 5.3 years). Group B was composed of 341 patients aged under 65 (185 men, 156 women, mean age 54.4 ± 9.1 years). Patients with uncontrolled arterial hypertension, hypertrophic cardiomyopathy, severe valve diseases, severe chronic obstructive lung diseases, severe anemia, peripheral atherosclerosis, orthopedic problems, or Parkinson's disease were excluded from the study. The term "important coronary artery disease" (iCAD) covers the following patterns of coronary anatomy: (a) left main stem stenosis ≥50% with or without disease elsewhere, (b) proximal three-vessel disease, (c) three-vessel disease including the proximal left anterior descending artery (LAD), (d) proximal two-vessel disease including LAD, and (e) two-vessel disease including the proximal LAD. Biostatistical characteristics such as sensitivity, specificity, and predictive values of ETT-201Tl were estimated. Analyzing our results we concluded that: the biostatistical parameters in predicting important CAD in elderly and younger patients by means of exercise test and thallium scintigraphy need to be redefined through more closely scheduled and prospective studies; in elderly coronary patients, the appearance of positive results in both parameters of ETT-201Tl indicates a significant possibility of iCAD existence; in coronary patients younger than 65 years, the appearance of negative results in both parameters of ETT-201Tl almost excludes iCAD, in contrast to elderly patients, who display a significant proportion of iCAD; in elderly coronary patients, the appearance of equivocal results in both tests indicates a significant possibility of the existence of iCAD, in contrast to younger patients.