Original Article
Normal Myocardial Perfusion Gated SPECT and Positive Stress Test: Different Prognoses in Women and Men

https://doi.org/10.1007/s12350-014-0009-zGet rights and content

Abstract

Background

The aim of this study was to analyze different prognoses in women and men with normal myocardial perfusion gated SPECT, according to stress test results.

Methods

Differences between women and men in terms of hard events (HE) (non-fatal acute myocardial infarction or cardiac death) and HE plus coronary revascularization (HE + CR) were analyzed in 2,414 consecutive patients (mean age 62.8 ± 13.5 years, 1,438 women) with a normal stress-rest gated SPECT, taking into account their stress test results.

Results

Four hundred and seven patients (16.9 %) (15.9 % women and 17.5 % men) had a positive stress test (ST-segment depression ≥1 mm and/or angina). During a follow-up of 5.1 ± 3.4 years, there were more significant HE (6.5 % vs 2.3 %; P = .005) and HE + CR (11.6 % vs 4.8 %, P = .001) in men with a positive stress test than in men with a negative stress test. These differences were not observed in women. In multivariate regression models, HE and HE + CR were also more frequent in men with a positive stress test (HR:3.3 [95 % CI 1.1 % to 9.5 %]; HR:4.2 [95 % CI 1.8 % to 9.9 %]; respectively) vs women with a positive stress test.

Conclusions

Although patients with normal gated SPECT studies have a favorable outcome, men with an abnormal stress test have a more adverse prognosis than women.

Introduction

Myocardial perfusion single photon emission computed tomography (SPECT) has been proposed as a gatekeeper to prevent unnecessary invasive cardiac procedures.1 Most studies after a normal myocardial perfusion SPECT have reported rates of hard events (HE) of <1 % per year of follow-up. However, clinical characteristics such as a history of coronary artery disease (CAD), diabetes, gender, increasing age,2, 3, 4, 5 and type of stress6, 7, 8, 9, 10 yield incremental prognostic value over SPECT data in patients with normal scans.

The pathophysiologic and prognostic value of a positive ECG in the presence of negative vasodilator myocardial perfusion imaging has been already investigated, although with conflicting results.11, 12, 13, 14 However, two recent studies15,16 with a very long follow-up (12-15 years) after normal myocardial perfusion SPECT observed that exercise parameters also can be used to identify patients with a higher risk status, because stress electrocardiogram provides further useful diagnostic and prognostic information. Although a normal SPECT with a positive stress electrocardiogram is infrequent, CAD cannot be ruled out, predominantly in men.17,18 The purpose of our study was to analyze different prognoses in women and men with a normal stress-rest myocardial perfusion gated SPECT, depending on the stress test results.

Section snippets

Methods

We analyzed 2,414 consecutive patients (mean age 62.8 ± 13.5 years, 1,438 female) with a normal stress-rest gated SPECT and suspected CAD. Patients were excluded in cases of cardiomyopathies, valvulopathies, myocardial infarction, coronary revascularization (CR), cardiac pacemaker, and abnormal ECG at rest before gated SPECT.

Results

The characteristics of the study population are shown in Figure 1 and Tables 1 and 2 according to gender and stress test results. Of the 2,414 patients, 407 (16.9 %: 17.5 % women and 15.9 % men, P = .290) had a positive stress test (Figures 2 and 3). Prevalence of cardiovascular risk factors (P < .001), exercise test (P < .001), and CR (P < .001) were more frequent in men. The prevalence of high, intermediate, and low pre-test probability of CAD were 21.3 % (N = 513), 11.2 % (N = 272), and 67.5

Discussion

In our series of patients with normal myocardial perfusion gated SPECT, 17.5 % of the women and 15.9 % of the men had a positive stress test. During a mean follow-up of 5.1 ± 3.4 years, there were more significant HE (6.5 % vs 2.3 %; P = .005) and HE + CR (11.6 % vs 4.8 %, P = .001) in men with a positive stress test than men with a negative stress test. In multivariate regression models, HE and HE + CR were also more frequent in men with a positive stress test (HR: 2.8 [95 % CI 1.3 % to 6.3

New knowledge gained

This is the first published study that prospectively explores the different prognoses in women and men with normal gated SPECT, according to stress test results (ST depression and/or angina). Men with an abnormal stress test have a more adverse prognosis than women. Males with normal SPECT but abnormal stress test required an accurate follow-up.

Conclusions

Although patients with normal myocardial perfusion gated SPECT studies have a favorable outcome, men with an abnormal stress test have a more adverse prognosis than women. As the prognosis is worse in men with normal SPECT and positive stress test, follow-up should be closer in these patients.

Study limitations

In our study, we did not assess pulmonary uptake and transient ischemic dilatation of the left ventricle at stress.28,29 These variables are markers of severe multi-vessel CAD and could also be predictors of poor clinical outcome in our series. It is possible that the study includes false-negative tests because the sensitivity of myocardial perfusion SPECT is not 100 %. Attenuation correction, which could have improved the accuracy of SPECT, was not used in this study. Furthermore, changes in

Acknowledgments

The authors are grateful to Prof. Demos Demosthenous (London) for his grammatical English correction.

Disclosure

Authors declared that they have no conflict of interest.

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