Diagnostic efficacy of stress technetium 99m-labeled sestamibi myocardial perfusion single-photon emission computed tomography in detection of coronary artery disease among patients over age 80

Background

Because symptoms of myocardial ischemia in elderly patients are often atypical, accurate noninvasive assessment of the presence, extent, and severity of coronary artery disease (CAD) would be especially useful to avoid unnecessary catheterization or invasive intervention. This study assessed the safety and diagnostic efficacy of ^99mTc-labeled sestamibi (^99mTcsestamibi) exercise and pharmacologic myocardial perfusion single-photon emission computed tomography (SPECT) with adenosine or dipyridamole in patients age 80 years or older.

Methods and Results

Stress ^99mTc-sestamibi SPECT was performed in 75 consecutive patients who were 80 years old or older (range: 80 to 91 years) with suspected CAD and who underwent coronary angiography within 6 months of the nuclear study. Of these patients, 51 underwent a pharmacologic (adenosine=42; dipyridamole=9) stress study and 24 underwent an exercise treadmill study. A normalcy rate was derived from an additional 36 patients (ages 83±3 years) who had undergone stress ^99mTc-sestamibi SPECT and who had a relatively low likelihood (<20%) of CAD. No serious adverse events occurred during or after the exercise or the pharmacologic stress test. The overall sensitivity and specificity for detecting CAD with ≥70% stenosis was 95% (52/55) and 75% (15/20), whereas the corresponding results were 87% (55/63) and 83% (10/12) for detecting patients with ≥50% stenosis. The sensitivity and specificity for pharmacologic stress ^99mTc-sestamibi SPECT were 95% (35/37) and 71% (10/14) for detecting ≥70% stenosis, and 86% (37/43) and 75% (6/8) for detecting CAD with ≥50% stenosis. The sensitivity and specificity of treadmill testing were 94% (17/18) and 83% (5/6) in detecting CAD with stenosis ≥70% and 90% (18/20) and 100% (4/4) in detecting CAD with stenosis ≥50%. The normalcy rate among the low likelihood patients was 83% (30/36). The accuracy of stress sestamibi testing was similar for patients with or without angina.

Conclusions

Our findings suggest that exercise or pharmacologic myocardial perfusion SPECT with ^99mTc-sestamibi is safe and diagnostically accurate for CAD detection in very elderly patients, irrespective of symptoms. Pharmacologic myocardial perfusion SPECT with adenosine or dipyridamole appears to be a valuable alternative to treadmill stress in very elderly patients incapable of performing adequate exercise.