GENDER-RELATED DIFFERENCES IN CLINICAL MANAGEMENT AFTER EXERCISE NUCLEAR TESTING

Objectives. This study sought to determine the rate of referral to car diac catheterization in men and women early after nuclear testing as a function of the magnitude of myocardial ischemia by radionuclide perf usion imaging. Background. Although many previous studies have suggest ed that gender-related differences are present in the clinical managem ent of coronary artery disease, the presence of such a difference with respect to referral to catheterization after noninvasive testing is d isputed. Methods. We examined 3,211 consecutive patients (1,074 women, 2,137 men) who underwent exercise dual-isotope single-photon emission computed tomography and had follow-np evaluation performed at least I year after nuclear testing (mean [+/-SD] follow-np 19 +/- 5 months) f or ''hard'' events (cardiac death and myocardial infarction) and refer ral to cardiac catheterization or revascularization within 60 days of nuclear testing. Multiple logistic regression analysis was performed t o determine the best predictors of referral to catheterization as web as to examine whether gender itself added further information to this model. Results. Although men were referred to catheterization more fre quently than women (10.6% vs. 7.1%, p < 0.001) early after exercise nu clear testing, there mere no differences in the rate of referral to ca theterization or revascularization after stratification by the amount of abnormally perfused myocardium detected by nuclear scan. Both men a nd women with normal scan results were infrequently referred to subseq uent catheterization. In the setting of severe ischemia, women were re ferred to catheterization more frequently than men. This higher rate a ppears to be clinically appropriate because women with severely abnorm al scan results had a significantly higher event rate than men (17.5% vs. 6.3%, p < 0.0001). This greater risk in women than in men appeared to be underappreciated because the increased rate of hard events in w omen with severely abnormal scan results was out of proportion to the smaller increase in their rate of referral to cardiac catheterization. Although gender added information to the multivariate model most pred ictive of referral to catheterization models when nuclear variables we re not included, when nuclear variables were considered, the addition of gender added no further significant information. This finding sugge sts that adjusting for differences in perfusion scan abnormalities by the use of nuclear testing eliminated the apparent gender-related refe rral bias. Conclusions. After controlling for differences in perfusion scan abnormalities, no gender-related referral bias to catheterizatio n was present. In the setting of severe ischemia, women had a greater rate referral to catheterization than men. As a function of risk, both men and women were appropriately referred to catheterization at a low rate when the scan resnlt was normal. However, because women with sev ere perfusion abnormalities had a greater rate of cardiac death and my ocardial infarction than men, women in this high risk subgroup were un derreferred to catheterization relative to men. This finding points to the need to better identify women at high cardiac risk.