Impact of myocardial perfusion single-photon emission computed tomography on referral to catheterization of the very elderly. Is there evidence of gender-related referral bias?

OBJECTIVES

This study sought to assess the impact of myocardial perfusion studies on subsequent management in the very elderly with respect to referral to catheterization or revascularization.

BACKGROUND

The very elderly are a rapidly growing segment of the U.S. population, and myocardial perfusion studies are frequently performed in this patient subset for evaluation of coronary artery disease.

METHODS

The study utilized 1,006 consecutive patients > or = 80 years old (511 men, 495 women) who underwent stress myocardial perfusion single-photon emission computed tomography (SPECT) using pharmacologic stress (n = 605) or treadmill exercise (n = 401). Referral to catheterization or revascularization within 60 days of the nuclear scan was correlated with clinical and nuclear variables.

RESULTS

Catheterization and revascularization were performed in 119 and 77 patients, respectively. Stratification of referral rates showed a low rate in normal and mildly abnormal scan categories and significantly higher rates in patients with severely abnormal scan results irrespective of the presenting symptoms or pretest likelihood of coronary artery disease. Multiple logistic regression analysis of clinical and nuclear variables revealed that extent and severity of reversibility by SPECT and the final scan result were the two most powerful predictors of referral to catheterization and revascularization in men and women (catheterization: chi-square 65 and 78; revascularization: chi-square 37 and 68, respectively). Overall, referral rates to catheterization and revascularization were similar in men and women (catheterization: 13% vs. 11%; revascularization: 8% vs. 8%, respectively). However, women with severely abnormal scan results were more frequently referred to catheterization (28% vs. 18%, p < 0.03) and revascularization (21% vs. 12%, p < 0.01) than men.

CONCLUSIONS

In patients > or = 80 years old, myocardial perfusion SPECT had a significant impact on patient management. The apparent discrepancy in referral rates for interventional management in men and women is unexplained but may be appropriate in light of our previous observations that women with severely abnormal scan results are at increased risk for hard cardiac events than are men with severely abnormal scan results.