Diagnostic accuracy of exercise ECG lead systems in clinical subsets of women

Regadenoson-induced T-wave heterogeneity complements coronary stenosis detection by myocardial perfusion imaging in men and women

AIMS

We analysed whether incorporating electrocardiographic interlead T-wave heterogeneity (TWH) with myocardial perfusion imaging (MPI) during pharmacologic stress improves detection of flow-limiting lesions (FLL).

METHODS AND RESULTS

Medical records of all 103 patients at our institution who underwent stress testing with regadenoson (0.4 mg IV bolus) within 3 months of coronary angiography from September 2017 to March 2019 were studied. Cases (N = 59) had angiographically significant FLL (≥50% of left main or ≥70% of other epicardial coronary arteries ≥2 mm in diameter); controls (N = 44) were normal or had non-FLL. TWH, i.e., interlead splay of T waves, was assessed from precordial leads V4-6 by second central moment analysis. Maximum TWHV4-6 levels during regadenoson stress were 68% higher in cases than in controls (P < 0.0001). TWHV4-6 generated areas under the receiver-operating characteristic (ROC) curve of 0.79 in men (P < 0.0001) and 0.71 in women (P = 0.007). In men, the ROC-guided 54-µV TWHV4-6 cut-point for FLL produced adjusted odds of 7.3 [95% confidence interval (CI): 1.3-41.5, P = 0.03], 79% sensitivity, and 78% specificity. In women, the ROC-guided 35-µV TWHV4-6 cut-point produced adjusted odds of 4.5 (95% CI: 1.1-18.9, P = 0.04), 84% sensitivity, and 52% specificity. Adding TWHV4-6 to MPI determinations reduced false-positive results by 70%, more than doubled true-negative results, and improved adjusted odds ratio to 6.8 (95% CI: 2.2-21.4, P = 0.001) with specificity of 78% in men and 86% in women.

CONCLUSION

This observational study is the first to demonstrate the benefit of combining TWHV4-6 with MPI to enhance FLL detection during MPI with regadenoson in both men and women.

[Myocardial ischaemia detection in women]

Screening of myocardial ischemia refers to the use of one or more diagnostic tests for coronary heart disease with a dual objective of appropriateness and promptness. In women, as compared to men, the accuracy of the different tests is worse. Thus, to overcome this sex-related penalty, we must define a diagnosis strategy based on risk stratification, enabling the identification of patients requiring invasive investigations. This review discusses various non-invasive diagnostic tests focusing on a female-specific approach and defines the use of numerous diagnostic tests with respect to both risk stratification and symptoms.

Improving the positive predictive value of exercise testing in women for coronary artery disease

The exercise treadmill test (ETT) in women has been limited by a low positive predictive value (PPV) for coronary artery disease (CAD). However, the reliability of previous studies was unsatisfactory because of the inclusion of younger women with a low prevalence of CAD. To further evaluate the diagnostic properties of the ETT in women, we evaluated a group of women with chest pain who had a positive ETT result and subsequent coronary angiography. Of the 111 women, 56 had significant CAD on angiogram, yielding a PPV of 51% for the group. However, inclusion in the analysis of several pretest attributes and specific exercise test responses improved the PPV of the ETT. Age had a major effect, with the youngest group (35 to 50 years old) having a PPV of 36% compared to 68% in the oldest group (>65 years old). Several specific exercise responses (ST-segment depression >2 mm and delayed ST-segment recovery >3.0 minutes) further separated true from false positives across all age groups, increasing the PPV to approximately 80%. Onset of ischemia at a relatively low cardiac workload of <80% maximum predicted heart rate was not a significant predictor. In conclusion, the standard ETT should remain the test of choice in ambulatory women with chest pain and no significant abnormalities on baseline electrocardiogram especially in those >65 years of age.

The accuracy of the electrocardiogram during exercise stress test based on heart size

BACKGROUND

Multiple studies have shown that the exercise electrocardiogram (ECG) is less accurate for predicting ischemia, especially in women, and there is additional evidence to suggest that heart size may affect its diagnostic accuracy.

HYPOTHESIS

The purpose of this investigation was to assess the diagnostic accuracy of the exercise ECG based on heart size.

METHODS

We evaluated 1,011 consecutive patients who were referred for an exercise nuclear stress test. Patients were divided into two groups: small heart size defined as left ventricular end diastolic volume (LVEDV) <65 mL (Group A) and normal heart size defined as LVEDV ≥65 mL (Group B) and associations between ECG outcome (false positive vs. no false positive) and heart size (small vs. normal) were analyzed using the Chi square test for independence, with a Yates continuity correction. LVEDV calculations were performed via a computer-processing algorithm. SPECT myocardial perfusion imaging was used as the gold standard for the presence of coronary artery disease (CAD).

RESULTS

Small heart size was found in 142 patients, 123 female and 19 male patients. There was a significant association between ECG outcome and heart size (χ(2) = 4.7, p = 0.03), where smaller hearts were associated with a significantly greater number of false positives.

CONCLUSIONS

This study suggests a possible explanation for the poor diagnostic accuracy of exercise stress testing, especially in women, as the overwhelming majority of patients with small heart size were women.

Gender differences in the treatment of non-ST-segment elevation myocardial infarction

BACKGROUND

Women are at greater risk for worse outcomes associated with acute coronary syndrome (ACS) than are men. One explanation may be that they tend to be treated less aggressively than men even when more aggressive treatment is warranted. The purpose of this analysis was to assess this issue.

METHODS

We used the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation (CRUSADE) Quality Improvement Initiative registry, an observational data collection that began in November 2001, with retrospective data collection from January 2001 to December 2006. A total of 32,888 subjects met the inclusion/exclusion criteria for our study, based on strong biochemical evidence of myocardial infarction and acute onset of typical cardiac chest pain. We stratified subjects into 16 cells for coronary intervention, based on 4 age groups and 4 cardiac catheterization findings (insignificant, 1-vessel disease, 2-vessel disease, 3-vessel disease). We also stratified subjects into 20 cells for medical treatment, based on 4 age groups and 5 medical treatments. In each cell we compared the rate of coronary intervention (coronary artery bypass grafting or percutaneous coronary intervention) or medical treatment (glycoprotein IIb/IIIa inhibitors, aspirin, clopidogrel, beta-blocker, and statins) for men vs women.

RESULTS

Men demonstrated significantly higher rates (P < 0.05) of coronary intervention in 7 of the 16 cells and 9 of the 20 medical treatment cells, compared to no cells in which women had statistically higher rates than men.

CONCLUSION

These findings suggest that men are more likely than women to receive coronary intervention and to be medically treated when presenting with evidence of non-ST-segment myocardial infarction, controlled for age, cardiac catheterization findings, and biochemical evidence of myocardial infarction.

Gender differences in correlates of troponin assay in diagnosis of myocardial infarction

Cardiac troponins are the most sensitive and specific biomarker for myocardial infarction (MI) diagnosis. If there is a gender bias in MI diagnosis, it could be reduced by more consistently applying objective diagnostic criteria to improve women's outcomes. This study set out to assess the accuracy and correlates of the cardiac troponin I (cTnI) assay in the diagnosis of non-ST-segment elevation MI, to determine how the assay accuracy and correlates vary by gender, and to explore the interaction between factors that may influence cTnI accuracy and affect gender differences in diagnosis. The data were obtained from the CHECKMATE study. It included 924 patients with possible myocardial ischemia excluding subjects with ST-segment elevation. The Dade-Behring Stratus CS STAT near-patient instrument (Dade Behring, Inc, Newark, Del) was used to measure cTnI. We assessed baseline troponin accuracy using a standard MI definition. There were 125 subjects with a definite MI diagnosis. Baseline troponin was 44% sensitive and 97% specific in predicting MI, with no significant gender differences. In contrast, other positive cardiac markers, namely rising or falling creatine-kinase MB fraction and positive electrocardiogram, occurred more frequently in men. Sensitivity (SE) of baseline troponin was higher in subjects where baseline troponin was obtained longer than 2 hours after the chest pain onset. The study did not observe a significant difference in the assay SE or specificity by gender. This observation, plus the fact that other positive cardiac markers occurred more frequently in men, suggest the troponin test may help to improve the diagnosis of MI in women.

Current status of stress echocardiography

Stress echocardiography is a widely applied technique for the evaluation of individuals with known or suspected coronary artery disease. The technique combines echocardiographic imaging with exercise testing or pharmacologic stress. Advances in digital image acquisition and harmonic imaging have substantially improved the quality of echocardiographic images, and have therefore increased general applicability of stress echocardiography.

Electrocardiogram abnormalities predict angiographic coronary artery disease in women with chest pain: results from the NHLBI WISE Study

BACKGROUND AND HYPOTHESIS

Noninvasive risk stratification for coronary artery disease (CAD) isless accurate in women than in men. Based on recent reports that gender-specific exercise electrocardiogram (ECG) parameters predict CAD, we evaluated the independent predictive value of the resting ECG for angiographic CAD in women with chest pain.

METHODS

Women (n = 850, mean age 58 years) with chest pain in the NHLBI Women's Ischemia Syndrome Evaluation (WISE) underwent 12-lead ECG testing and quantitative coronary angiography.

RESULTS

Significant angiographic CAD (> or = 50% stenosis in > or = 1 coronary) was present in 39% of women. Q waves in < or = 2 contiguous ECG leads were present in 107 women (13%), including 49 of 657 (7%) without history of infarction. Among 585 women without prior infarction orrevascularization, 48% of those with Q waves in contiguous leads versus 26% of others, had significant CAD (p = 0.003; odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.3-4.8). Women with Q waves in < or = 2 inferior ECG leads were particularly likely to have CAD (63 vs. 26% of others, p < 0.001; OR = 4.6,95% CI = 2.0-10.8). Other ECG findings predictive of CAD were any ST-T abnormality (OR = 1.9,95% CI = 1.3-2.8) and T-wave inversion (OR = 2.4, 95% CI = 1.3-4.2). In risk-adjusted analysis, inferior Q waves and T-wave inversion independently predicted significant CAD. When considered together with radionuclide perfusion test results, T-wave inversion on resting ECG added significant independent predictive value (OR = 2.8, 95% CI = 1.1-7.2, p = 0.03).

CONCLUSIONS

Selected resting ECG parameters independently predict angiographic CAD in women with chest pain, including women who have also undergone radionuclide stress testing. Prospective studies should consider resting ECG parameters in diagnostic algorithms for CAD in women.

Assessing the need for functional diagnostic testing in low-risk women with chest pain

OBJECTIVE

The objective of this study was to assess the need for functional diagnostic testing to identify coronary artery disease (CAD) in women presenting with chest pain and deemed at low risk in a chest pain evaluation unit (CPEU) setting.

METHODS

Low-risk women evaluated in a CPEU were defined as having < or =1 intermediate determinant of CAD (hypertension, tobacco use, or hypercholesterolemia) or < or =2 minor determinants (age, obesity, sedentary lifestyle, or family history of CAD). Patients were followed for 30 days for the occurrence of CAD, defined as a positive stress imaging study, significant CAD on angiography, myocardial revascularization, myocardial infarction (MI), or cardiac death.

RESULTS

Of 1355 consecutive women evaluated, 527 (39%) were classified as low risk. The rate of CAD in the low-risk group was 1.3% of which there were no coronary events.

CONCLUSION

Women admitted to a CPEU and identified as low risk are at very low risk for CAD.

Significance of ST depression during exercise treadmill stress and adenosine infusion myocardial perfusion imaging

BACKGROUND

ST segment depression on the electrocardiogram during the exercise treadmill test (ETT) is used as a predictor of coronary artery disease (CAD), although it is recognised that both false-positive and false-negative results limit the value of this procedure. Although adenosine does not produce an inotropic or chronotropic effect upon the myocardium it may cause ST depression during infusion.

METHODS

The 12-lead ECG recordings obtained during 825 adenosine stress and 425 ETT procedures, performed as part of a 2-day Tc-MIBI protocol, were retained for examination and comparison with the appearances at subsequent myocardial perfusion imaging (MPI).

RESULTS

ST depression was associated with 44 (4.9%) of the adenosine stress and 44 (10.4%) of the ETT procedures. Both 1 and 2 mm ST depression during adenosine stress were significant predictors of reversible ischaemia (p < 0.01; p < 0.01). However, even though 2 mm ST depression on ETT was significant as a predictor of reversible ischaemia (p < 0.01), 1 mm ST depression on ETT was not (p = 0.4). There were more female cases with false positive ECG changes in both the adenosine stress (63.6%) group and the ETT (66.7%) group. There was no significant correlation between the territory of the ischaemic changes seen on the ECG with the location of defects developing on MPI in both the adenosine stress and ETT groups.

CONCLUSIONS

ST depression of 1 mm occurring with adenosine stress, unlike with the ETT, is a significant predictor of ischaemia.

Improved capacity of exercise electrocardiography in the detection of coronary artery disease by focusing on diagnostic variables during the early recovery phase

The temporal distribution of the diagnostic information for the detection of coronary artery disease (CAD) provided by exercise-induced electrocardiographic (ECG) ST-segment amplitude changes in different ECG leads in men and women has not been fully investigated. To shed further light in this area, 1877 electrocardiograms selected from 8322 patients undergoing a routine exercise test on a bicycle ergometer were evaluated. ST-segment amplitude and the difference between heart rate-matched recovery and exercise ST-segment amplitudes (ST/HR difference) were measured. Coronary artery disease was verified angiographically in 669 patients and excluded in 1208 patients by angiography (n = 119), by myocardial scintigraphy (n = 250), or on clinical grounds (n = 839). The diagnostic performance of the 2 ECG methods used was assessed by constructing receiver operating characteristic curves for each sampling point every 12 seconds during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST-amplitude hysteresis assessed by the difference between recovery ST-segment amplitude and exercise ST-segment amplitude at matched heart rate. Both methods performed better in men and the diagnostic information appeared mainly in leads I, -aVR, II, V 4 , V 5 , and V 6 . The best discrimination of CAD is provided by analysis of ST-segment amplitude changes in 6 specific leads early during the recovery phase. This information should be targeted by exercise ECG diagnostic methods.

Exercise treadmill testing using a modified exercise protocol in women with suspected myocardial ischemia: findings from the National Heart, Lung and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

Exercise testing, a major diagnostic modality in individuals with suspected coronary artery disease (CAD), has in general demonstrated less overall diagnostic accuracy in women compared to men. As part of the WISE, a modified protocol was examined with the intention of improving reliability of exercise testing.

METHODS

Criteria for entry in the WISE study include clinically indicated coronary angiography. Exercise testing was performed using a protocol modified to be more appropriate for women. The study population consisted of 96 women, mean age of 55.8 y (range 34-77), who completed exercise treadmill test (ETT). Most (78%) were postmenopausal; 96% had >or =2 risk factors for CAD.

RESULTS

By core laboratory angiography, 29/96 women had stenosis > or =50% in at least one coronary artery. Of these 29 women, 9 had abnormal ETT, yielding overall sensitivity of 31%. The remaining 20 women had normal (12/29, 41%) or nondiagnostic (8/29, 28%) studies. Among the 67 women with minimal or no coronary stenosis, 35 had no ischemic ST-segment changes during ETT, yielding overall specificity of 52%. Analysis with exclusion of women with nondiagnostic studies yielded sensitivity and specificity of 43% and 66%, respectively. The presence of coronary artery stenosis and inability to perform ETT, but not results of testing, predicted the outcomes of myocardial infarction, heart failure, and death.

CONCLUSIONS

Exercise treadmill test appears to be of limited diagnostic value in women with suspected myocardial ischemia referred for coronary angiography. Sensitivity and specificity remain poor even with modified exercise protocol and core laboratory angiographic analysis. These findings merit consideration in view of current guidelines that recommend exercise testing in women with suspected CAD.

Gender and noninvasive diagnosis of coronary artery disease in women and men

OBJECTIVES

The purpose of this prospective study was to investigate the impact of the gender of physicians and patients on the accuracy of diagnosing coronary artery disease (CAD) based on the patient history only.

METHODS

Screening involved 1082 consecutive patients undergoing coronary angiography for suspected CAD. Known CAD was an exclusion criterion. The inclusion criteria were met by 144 patients (47 females). All patients were inverviewed by both an experienced male cardiologist (n=6) and an experienced female cardiologist (n=5), who had to state before coronary angiography if CAD was present relying solely on the patient interview. Eligible subjects also answered a questionnaire. Diagnostic performance to assess the presence or absence of CAD by history taking by male and female cardiologists, exercise testing, patient self-assessment, and the questionnaire were compared.

RESULTS

Coronary angiography showed significant CAD in 20 females (43%) and 70 males (72%). Diagnostic accuracy was not different between male (79%) and female (79%) cardiologists and comparable to the results of exercise testing (74%) but better than self-assessment by the patients (65%, p=0.01) or a questionnaire (68%, p=0.01). The accuracy of female physicians was better in men than in women (85% vs. 66%, p=0.01). The specificity of male physicians tended to be better in women than in men (74% vs. 59%, p=0.25). Female cardiologists overestimated the presence of CAD in women (specificity 48% vs. 74%, p=0.04).

CONCLUSIONS

The female cardiologists did not assess women more accurately than did their male colleagues. The diagnostic accuracy of these male and female cardiologists was quite good. However, both tend to assess patients of the opposite gender more specifically. There may be an impact of the gender of the physician on the accuracy of diagnosis of CAD by history taking.

The effect of estrogen compared to estrogen plus progesterone on the exercise electrocardiogram

OBJECTIVES

The objective of this study was to evaluate the effect of estrogen compared to estrogen plus progesterone on the stress electrocardiogram (ECG) in relationship to stress-gated myocardial perfusion imaging (MPI) in postmenopausal women.

BACKGROUND

It is generally recognized that estrogen may cause false positive ST depressions on the stress ECG. The effects of estrogen plus progesterone are not known. This study was performed to define the effects of these agents on the stress ECG correlated with results from MPI.

METHODS

We evaluated 140 postmenopausal women-31 not taking any hormone replacement therapy (HRT); 75 taking estrogen alone; and 34 taking estrogen plus progesterone. Women with a history of coronary artery disease (CAD), cardiomyopathy, or an abnormal resting ECG were excluded. All women underwent a symptom-limited treadmill test and MPI.

RESULTS

The overall sensitivity and specificity of the stress ECG compared to MPI in women not taking HRT was 54% and 78%, respectively. In women taking estrogen or estrogen plus progesterone, the sensitivity was unchanged. The power to detect clinically meaningful sensitivity difference (10%) was poor (p = 0.09). The specificity was reduced to 46% (p < 0.01) in women on estrogen therapy. In women taking estrogen plus progesterone, specificity was 80%.

CONCLUSIONS

Our results suggest that estrogen increases the false positive rate of the stress ECG. This decreased specificity is countered by co-administration of progesterone. Nonetheless, because the sensitivity of the stress ECG is only 50% to 57% in postmenopausal women, women at risk should have imaging in conjunction with stress for the optimal detection of CAD.

New parameters in the interpretation of exercise testing in women: QTc dispersion and QT dispersion ratio difference

BACKGROUND

It has been reported that the increase of QT dispersion (QTD) that occurs due to increased inhomogeneity of the ventricular repolarization because of transient ischemia obtained by standard 12-lead electrocardiogram (ECG), the changes during exercise, and the differences between exercise and rest increase the accuracy of exercise test in the diagnosis of coronary artery disease (CAD).

HYPOTHESIS

This study was designed to investigate the value of QTD parameters, which are reported to increase the diagnostic accuracy of exercise test in women.

METHODS

Ninety-seven women who had undergone coronary angiography and exercise test were evaluated for diagnosis of chest pain. QT dispersion was calculated using the measurements of the highest and lowest values of QT interval obtained by ECG during peak exercise. The QTc using Bazett's equation, and the QTD ratio (QTDR) using QT/RR were calculated, and QTcD and QTD ratios were obtained. The difference between QTcD and QTDR was determined by extracting the rest values from the exercise values.

RESULTS

The groups with normal coronaries (n = 48), single-vessel CAD (n = 24), and multivessel CAD (n = 25) were compared. The obtained QTD parameters at peak exercise and their differences between exercise and rest were found to be significantly increased in patients with CAD (p <0.001). Furthermore, these parameters were found to be higher in the patients with multivessel CAD than in those with single-vessel disease (p < 0.05). With the parameters QTcD > 60 ms and QTDR > 10%, greater sensitivity and specificity were obtained compared with ST-segment depression. The highest diagnostic accuracy was obtained with the QTD parameters calculated from the differences between rest and exercise values. The diagnostic accuracy of the difference of QTcD > 15 ms and the difference of QTDR > 5% was relatively higher than the other parameters (sensitivity, specificity, and negative and positive predictor values are 84, 88, 84, 87% and 84, 96, 85, 95%, respectively).

CONCLUSION

The use of QTD parameters as variables of ECG, which is easily obtainable in the evaluation of exercise ECG in women, increases the diagnostic accuracy of the exercise test. In addition, the evaluation of QTD variables may provide information about the incidence of CAD.

Is early invasive treatment of unstable coronary artery disease equally effective for both women and men? FRISC II Study Group Investigators

BACKGROUND

The Fragmin and fast Revascularization during InStability in Coronary artery disease (FRISC II) trial compared the effectiveness of an early invasive versus a noninvasive strategy in terms of the incidence of death and myocardial infarction (MI) in patients with unstable coronary artery disease (CAD).

OBJECTIVES

In this subanalysis, we sought to evaluate gender differences in the effect of these different strategies.

METHODS

The patients (749 women and 1,708 men) were randomized to early invasive or noninvasive strategies. Coronary angiography was performed within the first 7 days in 96% and 10% of the invasive and noninvasive groups, respectively, and revascularization was performed within the first 10 days in 71% and 9% of the invasive and noninvasive groups, respectively.

RESULTS

Women presenting with unstable CAD were older, but fewer had previous infarctions, left ventricular dysfunction and elevated troponin T levels. Women had fewer angiographic changes. There was no difference in MI or death at 12 months among women in the invasive and noninvasive groups (12.4% vs. 10.5%, respectively), in contrast to the favorable effect in the invasively treated group of men (9.6% vs. 15.8%, p < 0.001). In an interaction analysis, there was a different effect of the early invasive strategy for the two genders (p = 0.008).

CONCLUSIONS

Women with symptoms and/or signs of unstable CAD are older, but still have less severe CAD and a better prognosis compared with men. In contrast to its beneficial effect in men, an early invasive strategy did not reduce the risk of future events among women. Further research is warranted to identify the most appropriate treatment strategy in women with unstable CAD.

Usefulness of QT dispersion immediately after exercise as an indicator of coronary stenosis independent of gender or exercise-induced ST-segment depression

Several recent studies suggest that QT dispersion on a standard 12-lead electrocardiogram is a clinically useful indicator of significant coronary stenosis. In this study, we compared the diagnostic accuracy of QT dispersion immediately after exercise as an indicator of coronary stenosis in men and women, and in the presence or absence of exercise-induced significant ST-segment depression. The subjects were 273 consecutive patients (mean age 56 +/- 9 years; 190 men and 83 women) without a history of myocardial infarction who underwent treadmill exercise electrocardiography and coronary angiography for evaluation of angina. Of these, 146 patients had no significant coronary stenosis, 61 had single-vessel disease, 56 had multivessel disease, and 10 had left main coronary artery disease. QT dispersion immediately after exercise was significantly greater in patients with significant coronary stenosis than in those without (64 +/- 14 vs 39 +/- 14 ms, p <0.01). QT dispersion immediately after exercise was significantly more sensitive in men (sensitivity 75%; specificity 85%) and significantly more specific in women (sensitivity 77%, specificity 88%) than exercise-induced significant ST-segment depression (men: sensitivity 62%, specificity 74%; women: sensitivity 81%, specificity 68%) as an indicator of significant coronary stenosis. The addition of factors such as gender and the presence or absence of exercise-induced significant ST-segment depression did not significantly alter the sensitivity and specificity of QT dispersion immediately after exercise for detecting significant coronary stenosis (patients with significant ST-segment depression: sensitivity 77%, specificity 88%; patients without significant ST-segment depression: sensitivity 72%, specificity 86%). In conclusion, QT dispersion immediately after exercise is a clinically useful indicator of significant coronary stenosis independent of gender or the presence or absence of exercise-induced significant ST-segment depression.

Prognostic value of exercise echocardiography in women in the community setting

Treadmill stress echocardiography was performed in 1,136 women with known or suspected coronary artery disease whose clinical course was then evaluated a mean of 33 months later (range 12 to 60). The strongest predictor of an adverse outcome was the presence of a resting or an exercise-induced wall motion abnormality.

Dobutamine stress echocardiography in women with chest pain. Pilot phase data from the National Heart, Lung and Blood Institute Women's Ischemia Syndrome Evaluation (WISE)

OBJECTIVES

The aim of this project was to assess the utility of dobutamine stress echocardiography (DSE) for evaluation of women with suspected ischemic heart disease.

BACKGROUND

Most investigations addressing efficacy of diagnosis and treatment of coronary artery disease (CAD) have been performed in predominantly male populations. As part of the Women's Ischemia Syndrome Evaluation (WISE) study, DSE was assessed in women participating at the University of Florida clinical site.

METHODS

Women with chest pain or other symptoms suggestive of myocardial ischemia and clinically indicated coronary angiography were eligible for the WISE study. Enrolled subjects underwent DSE using a modified protocol. Coronary stenosis was assessed by core laboratory quantitative coronary angiography (QCA).

RESULTS

The 92 women studied ranged in age from 34 to 82 years (mean 57.5). All women had > or = 1 major risk for CAD, and most (89, 97%) had > or = 2 risk factors. In 78 women (85%), left ventricular wall motion was normal at baseline and during peak infusion. The remaining 14 women had wall motion abnormalities during DSE. By QCA, 25 women (27%) had > or = 50% coronary stenosis, including 10 with single-vessel obstruction. Dobutamine stress echocardiography was abnormal in 10 of these 25 women, yielding overall sensitivity of 40%, and 60% for multivessel stenosis. Exclusion of women with inadequate heart rate response yielded overall sensitivity of 50%, and 81.8% for multivessel stenosis. Dobutamine stress echocardiography was normal in 54 of the 67 women with < 50% coronary narrowing, specificity 80.6%.

CONCLUSIONS

Dobutamine stress echocardiography reliably detects multivessel stenosis in women with suspected CAD. However, DSE is usually negative in women with single-vessel stenosis, and in the larger subset without coronary stenosis. Ongoing protocols of the WISE study are expected to improve diagnostic accuracy in women with single-vessel disease, as well as provide important data in the substantial number of women with chest pain but without epicardial coronary artery stenosis.

Meta-analysis of exercise testing to detect coronary artery disease in women

To determine the accuracy of the exercise electrocardiogram (ECG), exercise thallium, and exercise echocardiogram (echo) for the diagnosis of coronary artery disease in women, English language studies published between 1966 and 1995 were identified through a MEDLINE search. Studies that contained data on at least 50 women who underwent both an exercise test and coronary angiography were examined. Studies were reviewed for sensitivity, specificity, and methodologic characteristics by 2 independent reviewers. Nineteen studies met the inclusion criteria for exercise electrocardiography, 5 studies for exercise thallium, and 3 studies for exercise echo. The exercise ECG had a weighted mean sensitivity, specificity, and a likelihood ratio (LR) of 0.61 (95% confidence intervals 0.54 to 0.68), 0.70 (0.64 to 0.75), (+) LR 2.25 (1.84 to 2.66), (-) LR 0.55 (0.47 to 0.62), respectively. The exercise thallium had a weighted mean sensitivity, specificity, and LRs of 0.78 (0.72 to 0.83), 0.64 (0.51 to 0.77), (+) LR 2.87 (1.0 to 4.96), (-) LR 0.36 (0.27 to 0.45). The exercise echo had a weighted mean sensitivity, specificity, and LRs of 0.86 (0.75 to 0.96), 0.79 (0.72 to 0.86), (+) LR 4.29 (2.93 to 5.65), (-) LR 0.18 (0.05 to 0.31). Thallium subset analysis revealed that studies using planar imaging were more specific than those using tomographic imaging. Thus, currently available exercise tests are only moderately sensitive and specific for the diagnosis of coronary artery disease in women.

The noninvasive prediction of cardiac mortality in men and women with known or suspected coronary artery disease. Economics of Noninvasive Diagnosis (END) Study Group

PURPOSE

The association between myocardial perfusion imaging defects and cardiac mortality in women is undefined. We examined whether myocardial perfusion imaging predicted cardiac mortality in men and women and compared this with other variables influencing prognosis.

SUBJECTS AND METHODS

Six academic institutions with high-volume nuclear cardiology laboratories consecutively studied 5,009 men aged 62 +/- 12 years (mean ISD) and 3,402 women aged 66 +/- 11 years with symptomatic known or suspected coronary artery disease undergoing exercise (n = 7,486) or pharmacologic stress (n = 925) myocardial perfusion imaging. A pretest clinical risk index was calculated from age, history of myocardial infarction, diabetes, hypertension, and hypercholesterolemia. Myocardial perfusion images were analyzed for stress-induced defects or any defect in the territories of the three major coronary arteries.

RESULTS

Stress-induced perfusion defects were seen in 39% of men and 25% of women (P = 0.0001). Extensive stress-induced or fixed defects (>2 vascular territories) were less common in women than men (10% vs 19%, and 4% vs 18%, both P = 0.0001). During a mean of 2.4 +/- 1.5 years of follow-up, 143 patients died of cardiac causes. The clinical risk index and number of territories with perfusion defects were associated with cardiac mortality in women and men. In women undergoing exercise myocardial perfusion imaging, the number of abnormal territories remained the strongest correlate of mortality after adjustment for exercise variables.

CONCLUSIONS

The results of myocardial perfusion imaging are important, independent predictors of survival in both women and men.

Gender differences in use of stress testing and coronary heart disease mortality: a population-based study in Olmsted County, Minnesota

OBJECTIVES

We sought to examine the utilization of exercise stress testing in relation to age and gender in a population-based setting.

BACKGROUND

The utilization of noninvasive procedures has been shown to be associated with the subsequent use of invasive procedures. Yet, there are no population-based data on the utilization of stress testing; in particular, although gender differences in the use of invasive procedures have been reported, the use of noninvasive procedures has not been examined in relation to gender.

METHODS

In Olmsted County, Minnesota, passive surveillance of the medical care of the community is provided through the Rochester Epidemiology Project. A population-based cohort of Olmsted County residents undergoing exercise tests was identified. The medical records of residents with prevalent and incident exercise tests in 1987 and 1988 were reviewed. For persons with an initial test (incidence cohort), data on clinical presentation, test indications and results were abstracted. Stress test utilization rates were calculated, and crude rates were directly adjusted to the age distribution of the 1980 U.S. population. To help interpret patterns of use at the population level, coronary heart disease mortality rates (International Classification of Diseases, 9th revision, codes 410 to 414) were calculated (crude and directly adjusted to the overall age distribution of the 1980 U.S. population) and used as an indicator of coronary disease burden.

RESULTS

A total of 2,624 tests were performed. The crude utilization rate (per 100,000) was 1,888 for men and 703 for women (rate ratio for men over women 2.7, 95% confidence interval [CI] 2.5 to 2.9); it remained significantly higher in men across all age strata. The crude incidence rate (per 100,000) of initial stress tests was 1,112 for men and 517 for women (rate ratio 2.2, 95% CI 1.9 to 2.4). For both men and women, the incidence increased with age; however, incidence remained lower in women in all age strata. At the time that they underwent an initial test, women were more symptomatic and had poorer exercise performance than men. The rate ratio of men over women for coronary heart disease mortality was 1.1 (95% CI 0.9 to 1.2). The age-adjusted rate ratios for stress test utilization were 2.8 (95% CI 2.5 to 3.0), and that for coronary heart disease mortality was 1.9 (95% CI 1.7 to 2.2).

CONCLUSIONS

These population-based data show that during the study period, the utilization of stress testing in Olmsted County was lower in women than in men. Women in the incidence cohort were older and more symptomatic and had poorer exercise performance than men. Such differences should be considered when examining the utilization of subsequent invasive procedures according to gender.

Perioperative cardiac evaluation for noncardiac surgery noninvasive cardiac testing

Prognostic risk stratification to identify perioperative and long-term cardiac risk in selected patients undergoing noncardiac surgery is part of good clinical practice. Exercise variables associated with significant increased risk include poor functional capacity (eg, <4 metabolic equivalents), marked exercise-induced ST segment shift or angina at low workloads, and inability to increase or actually decrease systolic blood pressure with progressive exercise. Approximately 40% of patients tested before peripheral vascular surgery will have an abnormal exercise electrocardiogram (ECG). The predictive value for a perioperative event, ie, death or myocardial infarction, ranges from 5% to 25% for a positive test and 90% to 95% for a negative test. Whereas exercise cardiac imaging is the modality of choice in patients with a noninterpretable exercise ECG, pharmacological stress imaging should be used in the 30% to 50% of patients who require perioperative noninvasive risk stratification and are unable to perform an adequate level of exercise to test cardiac reserve. Myocardial perfusion variables predictive of increased cardiac events include severity of the perfusion defect, number of reversible defects, extent of fixed and reversible defects, increased lung uptake of thallium-201, and marked ST segment changes associated with angina during the test. The reported sensitivity and specificity of dobutamine-induced echocardiographic wall motion abnormalities in patients with peripheral vascular disease is similar to myocardial perfusion scintigraphy, but the confidence limits are wider due to the smaller sample size in these more recent studies. In conclusion, noninvasive cardiac testing should be used selectively in patients undergoing noncardiac surgery; the results provide useful estimates of short- and long-term risk of cardiac events, and the magnitude of abnormal response on noninvasive testing should be used to formulate decisions regarding the need for coronary angiography and subsequent revascularization.

Multiplane transoesophageal echocardiographic detection of thoracic aortic plaque is a marker for coronary artery disease in women

OBJECTIVE

This study was conducted to examine if the multiplane transoesophageal echocardiographic detection of atherosclerotic plaque in the thoracic aorta could predict the absence or the presence and the severity of significant coronary artery disease in women. Its association with coronary disease is attractive and may have great influence on foregoing routine preoperative cardiac catheterization in patients with valvular heart disease but no data are available in women.

METHODS

Clinical and angiographic features and transoesophageal echocardiographic findings were prospectively analysed in 111 women.

RESULTS

In 24 women with significant coronary disease, 20 had thoracic aortic plaque on transoesophageal echocardiographic studies. In contrast, aortic plaque existed in only 12 of the remaining 87 women with normal or mildly abnormal coronary arteries. Therefore, the presence of aortic plaque had a sensitivity of 83%, a specificity of 86%, a positive and negative predictive values of 62% and 95%, respectively for the detection of significant coronary disease. There was a significant relation between the severity and the extent of atherosclerotic lesions and the angiographic coronary score (P<0.0001). Multivariate logistic regression analysis revealed that aortic plaque was the most significant independent marker of coronary disease (odds ratio=27.9; 95% confidence interval=5.5-131.6; P<0.0001).

CONCLUSIONS

This prospective study indicates that multiplane transoesophageal echocardiographic examination of thoracic atherosclerotic plaque is a marker for coronary disease in women and especially a powerful predictor of absence of significant coronary artery disease. Transoesophageal echocardiographic aortic examination might be used with risk factors and angina symptoms to discuss the need for preoperative coronary angiography in women with valvular heart disease.

Prognostic implications of exercise echocardiography in women with known or suspected coronary artery disease

OBJECTIVES

The purpose of this study was to define the value of exercise echocardiography as an independent predictor of cardiac events in women with known or suspected coronary artery disease (CAD), incremental to the data provided by clinical evaluation and exercise testing.

BACKGROUND

Exercise echocardiography is more accurate than exercise electrocardiography for the identification of CAD in women. However, the prognostic implications of exercise echocardiography, especially relative to exercise electrocardiography, are undefined.

METHODS

Symptom-limited exercise echocardiography was performed in 549 consecutive women between 1989 and 1993. Echocardiography and electrocardiography were performed before and after treadmill exercise; an abnormal result on exercise electrocardiography was defined by ST segment depression > 0.1 mV, ischemia by exercise echocardiography as a new or worse wall motion abnormality after exercise and scar by akinesia or dyskinesia at rest. After exclusion of six patients with uninterpretable studies (1%) and 35 (6%) lost to follow-up, 508 women (mean [+/-SD] age 55 +/- 11 years) were followed up for 41 +/- 10 months for cardiac-related death, infarction or late revascularization.

RESULTS

The group attained 92 +/- 10% of age-predicted maximal heart rate, with an exercise capacity of 7 +/- 2 metabolic equivalents. Of 420 women with an interpretable electrocardiogram, significant ST segment changes were present in 68 (16%). Results of exercise echocardiography were normal in 413 (81%) women, positive for ischemia in 66 (13%) and scar only in 29 (6%). No events occurred in 444 patients (89%), and 19 underwent primary revascularization (within 3 months of exercise test). Cardiac events occurred in 36 women (7%), including 17 who died of cardia causes and 19 who had a myocardial infarction or required late revascularization for progressive symptoms. On univariate analysis, the variables associated with cardiac mortality and total cardiac events were a history of CAD, diabetes, left ventricular hypertrophy, exercise capacity and echocardiographic evidence of myocardial ischemia and infarction. A Cox proportional hazards model showed the independent predictors of outcome to be known CAD (odds ratio [OR] 6.6, 95% confidence interval [CI] 3.2 to 13.7, p < 0.00001) and echocardiographic ischemia (OR 4.3, 95% CI 2.1 to 8.7, p < 0.0001). The prognostic value of exercise echocardiography incremental to clinical and exercise variables was demonstrated using sequential Cox models.

CONCLUSIONS

In this large cohort of women, exercise echocardiography provided key prognostic information incremental to clinical and exercise testing data.

The specificity of exercise electrocardiography in women grouped by estrogen status

We compared the specificity of exercise electrocardiography in 1880 men and 1818 women with women grouped by menopausal and estrogen replacement status. Specificity for > or = 1 mm horizontal or downsloping ST-segment depression was determined using angiography in 781 patients and using two other nonangiography-based methods (a pretest probability-based method and a predictive accuracy-based method) in all patients. Using angiography, the specificities+/-SE were 84 +/- 2 for men, 79 +/- 3 for women, 81 +/- 5 for premenopausal women, 81 +/- 4 for postmenopausal women without estrogen replacement, and 77 +/- 5 for women on estrogen replacement. None of these were significantly different. For all patients, the respective specificities using the probability and predictive accuracy-based methods were 97 +/- 1 and 94 +/- 1 for men, 90 +/- 1 and 88 +/- 1 for women, 97 +/- 1 and 92 +/- 2 for premenopausal women, 92 +/- 4 and 88 +/- 3 for postmenopausal women without estrogen replacement, and 85 +/- 4 and 81 +/- 3 for women on estrogen replacement. (Men vs. all women groups except premenopausal women-P < 0.05). Therefore, the premenopausal women had significantly greater specificity than women on estrogen replacement (P < 0.001) and no difference in specificity with men. Women on estrogen replacement had a significantly lower specificity than postmenopausal women not on estrogen replacement (P < 0.05). These results suggest that estrogen replacement therapy and not naturally occurring estrogen has a role in producing false positive exercise electrocardiograms in women.

Comparative diagnostic accuracy of Tl-201 and Tc-99m sestamibi SPECT imaging (perfusion and ECG-gated SPECT) in detecting coronary artery disease in women

OBJECTIVES

This prospective study was conducted in 115 women to directly compare the sensitivity and specificity of thallium-201 (Tl-201), technetium-99m (Tc-99m) sestamibi perfusion and Tc-99m sestamibi electrocardiographic (ECG)-gated single-photon emission computed tomographic (SPECT) studies for detection of coronary artery disease (CAD).

BACKGROUND

Data on the comparative diagnostic accuracy of Tl-201 and Tc-99m sestamibi perfusion imaging for the detection of CAD, specifically in women, are very limited.

METHODS

Eighty-five patients with suspected CAD, scheduled for coronary angiography, and 30 volunteers with a pretest likelihood of < or = 5% for CAD were evaluated. Within 1 week, each patient underwent Tl-201 and Tc-99m sestamibi SPECT imaging procedures (both perfusion and gated SPECT imaging). Treadmill stress testing was used in 78 patients and dipyridamole in the remaining 37 patients. All images were interpreted by three observers in a blinded manner (consensus reading). Technetium-99m sestamibi SPECT studies were read without and then with ECG gating. Technetium-99m sestamibi gated SPECT studies were used to differentiate scar tissue from soft tissue attenuation artifact.

RESULTS

The overall sensitivities for detecting > or = 50% and > or = 70% stenoses were 75.0% and 84.3%, respectively, for Tl-201, and 71.9% and 80.4%, respectively, for Tc-99m sestamibi perfusion studies (p = 0.48). The specificity for lesions > or = 50% was 61.9% for Tl-201 and 85.7% for Tc-99m sestamibi perfusion (p = 0.07), whereas for lesions > or = 70% it was 58.8% for Tl-201 and 82.4% for Tc-99m sestamibi perfusion (p = 0.01). When the 34 patients with a normal coronary angiogram were added to the group of 30 normal volunteers, the "specificity" for lesions > or = 70% was 67.2% for Tl-201, 84.4% for Tc-99m sestamibi SPECT perfusion (p = 0.02) and 92.2% for Tc-99m sestamibi gated SPECT (p = 0.0004).

CONCLUSIONS

Both Tl-201 SPECT and Tc-99m sestamibi SPECT perfusion studies had a similar sensitivity for the detection of CAD in women. However, Tc-99m sestamibi SPECT perfusion imaging shows a significantly better specificity, which is further enhanced by the use of ECG gating.

Women with chest pain: is exercise testing worthwhile?

OBJECTIVE

To determine the diagnostic value of the exercise tolerance test (ETT) in women presenting with chest pain.

DESIGN

Prospective study of all women presenting to a centre with chest pain between 1987 and 1993 who were assessed by an ETT and coronary angiography.

SETTING

The outpatient clinic of one consultant cardiologist in a tertiary referral centre.

PATIENTS

All women referred to this outpatient clinic with chest pain were screened. For inclusion, patients had to perform ETT and undergo coronary angiography. Of the 347 referred during this period, 142 were excluded because they were unable to perform ETT or because of Q waves or other abnormalities on their resting electrocardiogram.

RESULTS

Overall the sensitivity of the ETT was 68% and the specificity was 61%, with a positive predictive value of 0.61 and a negative predictive value of 0.68. There were 42 false positive and 31 false negative ETT results (36% of the study group). The predictive value of a negative test was higher in younger women (< 52 years) than in the older group (> or = 52 years) (P = 0.004), but the positive predictive value in the two groups was not significantly different. The predictive value of a negative test was also higher in those with two or fewer risk factors than in those with three or more risk factors (P = 0.001). The negative predictive value for those women above 52 years with three or more risk factors (24% of the study group) was only 0.25. Lack of chest pain during ETT was associated with a higher negative predictive value in the younger group than in the older women (P = 0.006).

CONCLUSIONS

In women with chest pain use of the ETT was a misleading predictor of the presence or absence of coronary disease in 36% of these patients. In particular, a negative test in older women with three or more risk factors had a very low predictive value. The inclusion of risk factors and division by age can, however, be used to identify a population at intermediate risk for coronary artery disease in whom the ETT result has the highest diagnostic utility.

Detection and significance of myocardial ischemia in women versus men within six months of acute myocardial infarction or unstable angina. The Multicenter Myocardial Ischemia Research Group

Ischemia detection after an acute coronary event predicts subsequent cardiac events. However, gender-related aspects in the prevalence and prognostic significance of ischemia detection after an acute coronary event have not been reported. Noninvasive tests, which included resting 12-lead electrocardiogram (ECG), 24-hour ambulatory ECG, exercise ECG, and thallium-201 stress scintigraphy were performed in 936 stable patients (224 women and 712 men) 1 to 6 months (average 2.7) after an acute coronary event (i.e., myocardial infarction or unstable angina). Primary end points during an average follow-up of 23 months included cardiac death, nonfatal myocardial infarction, and unstable angina, while restricted end points included the first 2. Ischemia detection was significantly less frequent among women than among men on 24-hour ambulatory ECG, exercise ECG, and thallium-201 stress scintigraphy. Primary end points occurred in 19.2% of women and in 19% of men, and restricted end points occurred in 5.8% of women versus 8%. of men (p = NS). Cox analyses revealed that gender and its interaction with each of the ischemia tests did not contribute to the prediction of the primary or restricted end points. We conclude that in stable patients 1 to 6 months after an acute coronary event, ischemia detection by noninvasive tests was significantly less prevalent in women than in men. However, subsequent cardiac event rates in women were similar to those observed in men, and there was no gender-ischemic detection interaction regarding subsequent events.

Comparison of the sensitivity and specificity of exercise electrocardiography in biased and unbiased populations of men and women

To assess for sex-related differences in posttest referral bias, we compared the accuracy of exercise electrocardiography in biased (coronary angiography only) and unbiased (all unselected) populations with possible coronary disease. A retrospective analysis of clinical and exercise test data from 4467 patients (788 who underwent angiography) was performed (2824 men and 1643 women). The accuracy of a positive exercise test result was assessed in the entire unbiased group with a method that used disease probability (derived with a logistic algorithm) rather than angiography results. We found that the sensitivity and specificity were significantly greater in men than in women with use of the biased or unbiased groups. When the results for the unbiased and biased groups were compared, the sensitivities for the unbiased group were significantly lower and the specificities were significantly higher than those of the biased group. These differences reflect the effects of posttest referral bias. The amounts that sensitivity decreased and specificity increased, however, was not different for men and women. Therefore, we conclude that the accuracy of exercise electrocardiography is lower in women than men irrespective of whether a biased or an unbiased group is used. However, these differences cannot be explained on the basis of sex-related differences in posttest referral bias.

Exercise echocardiography is an accurate and cost-efficient technique for detection of coronary artery disease in women

OBJECTIVES

This study compared the accuracy and cost implications of using exercise echocardiography and exercise electrocardiography for detection of coronary artery disease in women.

BACKGROUND

The specificity of exercise electrocardiography in women is lower than in men. Exercise echocardiography accurately identifies coronary artery disease in women, but its utility in place of exercise electrocardiography is unclear.

METHODS

One hundred sixty-one women without a previous Q wave infarction underwent exercise echocardiography and coronary angiography. Positive findings were a new or worsening wall motion abnormality on the exercise echocardiogram and ST segment depression > 0.1 mV at 0.08 s after the J point on the exercise electrocardiogram (ECG).

RESULTS

Coronary artery stenosis > 50% diameter narrowing was present in 59 patients; the sensitivity (mean +/- SD) of exercise echocardiography was 80 +/- 3%. In 48 patients with an interpretable ECG, the sensitivity of exercise echocardiography was 81 +/- 4%, and that of the exercise ECG was 77 +/- 3% (p = 0.50). In 102 patients without coronary artery disease, the overall specificity of exercise echocardiography was 81 +/- 4%. In 70 patients with an interpretable ECG, the specificity of exercise echocardiography (80 +/- 3%) exceeded that of the exercise ECG (56 +/- 4%, p < 0.0004). The accuracy of exercise echocardiography was also greater than exercise electrocardiography (81 +/- 5% vs. 64 +/- 6%, p < 0.005). Exercise echocardiography stratified significantly more patients of intermediate (20% to 80%) pretest disease probability into the high (> 80%) or low (< 20%) posttest probability group. In women without a previous exercise ECG, the specificity of exercise echocardiography continued to exceed that of exercise electrocardiography (80 +/- 3% vs. 64 +/- 3%, p = 0.05). Exercise echocardiography had the best balance between accuracy and cost for the diagnosis of coronary artery disease in women.

CONCLUSIONS

Exercise echocardiography is more specific than exercise electrocardiography for diagnosis of coronary artery disease in women and is a cost-effective approach to the diagnosis of coronary artery disease because of the avoidance of inappropriate angiography.

Comparison of exercise echocardiography with an exercise score to diagnose coronary artery disease in women

This study compares the accuracy of the routine exercise electrocardiogram, exercise score, and exercise echocardiography for the diagnosis of coronary artery disease (CAD) in women. Seventy women with a pretest probability of 53 +/- 30% for CAD were stressed using a maximal symptom-limited bicycle exercise protocol. Significant ST-segment change was defined by a depression of > 0.1 mV 0.06 second after the J point. The exercise score was calculated from ST response, heart rate, and workload using an equation derived from a multivariate model. A positive stress echocardiogram was defined by development of a new or worsening wall motion abnormality. The results were compared with the presence or absence of significant (> 50% diameter) stenoses at angiography. Exercise echocardiography identified 29 of the 33 patients (88%) with CAD, compared with 22 (67%) using ST analysis alone, and 20 (61%) using the exercise score (both p < 0.05 vs exercise echocardiography). The specificity of exercise echocardiography (84%) and the multivariate score (73%) were comparable, and exceeded that of the ST analysis (51%) in 37 patients without CAD (p < 0.01). The accuracy of exercise echocardiography (86%) exceeded that of the exercise score (67%, p = 0.01) and ST analysis (59%, p < 0.01). Among all 70 patients, an intermediate (20% to 80%) probability of coronary disease was identified in 21 patients on the basis of exercise echocardiography, in 38 based on the multivariate score, and in 38 based on the ST analysis alone. Exercise echocardiography is more sensitive than the exercise score, and more sensitive and specific than ST-segment analysis for the diagnosis of CAD in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Value of a simple measure of estrogen status for improving the diagnosis of coronary artery disease in women

PURPOSE

To determine the potential impact of estrogen status on the pretest and postexercise test diagnostic accuracy of exercise testing.

PATIENTS AND METHODS

The study comprised a total of 234 women and 326 men who underwent exercise testing followed by coronary angiography. We performed incremental logistic regression analysis of pretest (age, symptoms, smoking, diabetes, cholesterol level) with and without estrogen status (defined according to menopausal and oral estrogen status) and exercise test (two ST-segment and three non-ST-segment) variables separately for men and women. Outcomes were assessed by receiver operating characteristic (ROC) curve area analysis.

RESULTS

Estrogen status was an independent pretest predictor of angiographic coronary disease. Pretest ROC curve areas: women without estrogen status = 0.79, women with estrogen status = 0.85, men = 0.78 (women with estrogen status versus other groups, p < 0.001). Postexercise test ROC curve areas: women without estrogen status = 0.83, women with estrogen status = 0.87, men = 0.88 (women without estrogen status versus other groups, p < 0.001).

CONCLUSION

Consideration of estrogen status allowed for a significant improvement in the pretest clinical diagnosis of coronary disease in women. When these improvements were added to the results of exercise testing, the diagnostic accuracy of the combined clinical and exercise test data was similar for men and women. Estrogen status may be an important diagnostic clinical variable in women with suspected coronary disease.

Coronary artery disease in women. How it is--and isn't--unique

Various risk factors, such as smoking and diabetes, have an adverse effect on women's inherent biological protection from coronary artery disease (CAD). In women, CAD is most likely to present as angina. Although infarction as the initial event is less common in women than in men, it is more likely to be fatal. The prognosis for women with diabetes and CAD is especially poor. Differences in the therapeutic approach to CAD in men and women do not appear justified. Preventive strategies for women center around cessation of smoking, aspirin therapy, diet modification, and estrogen therapy.

The predictive value of silent ischemia at an exercise test before discharge after an episode of unstable coronary artery disease. RISC Study Group

The prognostic value of silent ischemia during a symptom-limited predischarge exercise test (ET) was evaluated in 740 men after an episode of unstable angina or non-Q wave myocardial infarction. The 51% of patients with ST depression at the ET had a higher rate of myocardial infarction or death after 1 year (18%) compared with those without ST depression (9%; p less than 0.01). This increased risk was not influenced by the presence or absence of pain at the ET: 18.3% in patients with painful ischemia compared with 18.1% in patients with silent ischemia. However, ST depression combined with pain at the ET predicted a higher incidence of class III or IV angina at follow-up (43.9% compared with 16.7% in the group with asymptomatic ST depression; p less than 0.001). Because revascularization in addition to alleviating symptoms also enhances the prognosis in certain groups of patients, selections for coronary angiography and possible revascularization should not be made only on the basis of symptoms but also on the presence of myocardial ischemia, whether symptomatic or not.

Logistic discriminant analysis improves diagnostic accuracy of exercise testing for coronary artery disease in women

BACKGROUND

Diagnostic accuracy of the exercise electrocardiogram in women has been shown to be limited for the detection of coronary artery disease. New diagnostic methods based on computer analysis of the exercise electrocardiogram and multivariate analysis have improved the diagnostic value of exercise testing in male subjects. The aim of the present study was to assess whether the diagnostic value of exercise testing can be enhanced in women by using multivariate analysis of exercise data.

METHODS AND RESULTS

Between 1978 and 1984, 135 infarct-free women underwent exercise testing and coronary angiography. Significant coronary artery disease was present in 41% of the patients. In this first group, maximal exercise variables were submitted to a stepwise logistic analysis. Work load, heart rate, and ST60X were selected to build a diagnostic model. The model was tested in a second group of 115 catheterized women (significant coronary artery disease in 47%) and of 76 volunteers. We compared the present model with conventional analysis of the exercise electrocardiogram, with ST changes adjusted for heart rate, and with a previously described analysis. In both groups, sensitivity was better with the present model (66% and 70%) than by conventional (68% and 59%) and by the previously described analysis (57% and 44%) without a loss of specificity (85% and 93%). Receiver-operator characteristic curves showed also a better diagnostic accuracy with the present model.

CONCLUSIONS

In women, logistic analysis of exercise variables improves the diagnostic value of exercise testing. It yields a significantly better sensitivity without a loss of specificity.

Degree of coronary artery disease predicted by exercise testing

The ability of exercise testing to predict the extent of coronary artery disease was examined in 268 male patients undergoing both coronary angiography and bicycle testing with electrocardiography before coronary artery bypass surgery. When maximal ST-depressions limited by symptoms increased from 0 to 4 mm or more, the percentage of patients with 'serious' coronary disease, defined as either triple vessel disease or left main stem stenosis, increased from 50% to 80% (P = 0.0001). The patients in the lowest third of physical work capacity showed only a slightly increased risk of serious disease. This tendency was abolished in patients who were using beta-blockers, whereas the relationship between ST-depression and disease was not affected by this medication. The probability of finding left main stem stenosis in a patient increased from 5 to 30% with increasing ST-depression: beta-blockers did not affect this relationship, but there was no additional predictive effect of implicating the level of physical work capacity. It is concluded that traditional electrocardiography during exercise is of value when selecting patients for angiography, but that the physical work level obtained during the test does not predict the degree of coronary pathology.

Effects of carbon monoxide on myocardial ischemia

The purpose of this study was to determine whether low doses of carbon monoxide (CO) exacerbate myocardial ischemia during a progressive exercise test. The effect of CO exposure was evaluated using the objective measure of time to development of electrocardiographic changes indicative of ischemia and the subjective measure of time to onset of angina. Sixty-three male subjects (41-75 years) with well-documented coronary artery disease, who had exertional angina pectoris and ischemic ST-segment changes in their electrocardiograms, were studied. Results from three randomized, double-blind test visits (room air, low and high CO) were compared. The effect of CO exposure was determined from the percent difference in the end points obtained on exercise tests performed before and after a 1-hr exposure to room air or CO. The exposures resulted in postexercise carboxyhemoglobin (COHb) levels of 0.6% +/- 0.3%, 2.0% +/- 0.1%, and 3.9% +/- 0.1%. The results obtained on the 2%-COHb day and 3.9%-COHb day were compared to those on the room air day. There were 5.1% (p = 0.01) and 12.1% (p less than or equal to 0.0001) decreases in the time to development of ischemic ST-segment changes after exposures producing 2.0 and 3.9% COHb, respectively, compared to the control day. In addition, there were 4.2% (p = 0.027) and 7.1% (p = 0.002) decreases in time to the onset of angina after exposures producing 2.0 and 3.9% COHb, respectively, compared to the control day. A significant dose-response relationship was found for the individual differences in the time to ST end point and angina for the pre- versus postexposure exercise tests at the three carboxyhemoglobin levels. These findings demonstrate that low doses of CO produce significant effects on cardiac function during exercise in subjects with coronary artery disease.

Accuracy of exercise electrocardiography in detecting physiologically significant coronary arterial lesions

The accuracy of exercise electrocardiography in detecting a physiologically significant coronary artery stenosis has been assessed previously by comparing the exercise test with a coronary arteriogram. The inherent inaccuracy of visually determined percent diameter stenosis measurements might have lead to the conclusion that the exercise electrocardiogram was less accurate than it truly was. To determine the accuracy of the exercise electrocardiography in detecting a physiologically significant coronary stenosis, we studied 40 patients with one-vessel, one-lesion coronary artery disease, a normal resting electrocardiogram, and no hypertrophy or prior infarction. Each patient underwent exercise electrocardiography (Bruce protocol) that was interpreted as abnormal if the ST segment developed 0.1-mV or greater depression 80 msec after the J point. The physiological significance of each coronary stenosis was assessed by measuring of coronary flow reserve (peak divided by resting blood flow velocity) in the stenotic artery using a Doppler catheter and intracoronary papaverine (normal, 3.5 or greater peak/resting velocity). The percent diameter and percent area stenosis produced by each lesion were determined using quantitative angiography (Brown/Dodge method). Of the 17 patients with reduced coronary flow reserve (3.5 or greater peak/resting blood flow velocity) in the stenotic artery, 14 had an abnormal exercise electrocardiogram (sensitivity, 0.82; 95% confidence interval, 0.70-0.94). Conversely, 20 of 23 patients with normal coronary flow reserves had normal exercise tests (specificity, 0.87; 95% confidence interval, 0.77-0.97). The exercise electrocardiogram was abnormal in each of 11 patients with markedly reduced coronary flow reserve (less than 2.5 peak/resting velocity) and in three of six patients with moderately reduced reserve (2.5-3.4 peak/resting velocity). The products of systolic blood pressure and heart rate at peak exercise were significantly correlated with coronary reserve in patients with truly abnormal exercise tests. In comparison, the sensitivity (0.61; 95% confidence interval, 0.46-0.76) and specificity (0.73; 95% confidence interval, 0.60-0.86) of exercise electrocardiography in detecting a 60% or greater diameter stenosis may be significantly lower (p less than 0.05). Exercise electrocardiography, therefore, was a good predictor of the physiological significance (assessed by coronary flow reserve) of a coronary stenosis in patients with a normal resting electrocardiogram and no hypertrophy or prior infarction. Its value in a broader and larger patient population will require further study. These results, however, underscore the importance of a physiological gold standard in assessing the accuracy of noninvasive studies for detecting coronary artery disease.

Changes in the electrocardiographic response to exercise in healthy women

Changes in the P wave, QRS complex, ST segment, and T wave during and after maximal exercise were quantitatively analysed in 116 healthy women with a mean age of 39. The corrected orthogonal Frank lead electrocardiogram was continuously recorded and computer processed during bicycle ergometry. With exercise, maximal spatial P wave vectors shifted downward. The Q wave amplitude became more negative and the R wave amplitude diminished considerably in leads X and Y: the S wave amplitude decreased only slightly in these leads. The QRS vectors shifted towards right and posteriorly during exertion and a further shift in the same direction was seen in the recovery period. The ST segment amplitude 60 ms after the J point decreased with exertion and became negative at heart rates above 140 beats per minute, in particular in lead Y. ST segment depression increased with age. The T wave amplitude decreased during exercise and increased sharply in the recovery period. Though mean R wave amplitude in leads X and Y became more negative with exercise, this response was unpredictable in individual women. The exercise induced changes in QRS vectors in women resembled those described in men. Changes in the amplitude of the R wave should not be used for the diagnosis of coronary disease in women. ST segment depression was more pronounced in the inferiorly oriented lead Y than in lead X but it was unrelated to changes in the QRS vectors in these leads.