Prognostic value of adenosine single-photon emission computed tomographic thallium imaging in medically treated patients with angiographic evidence of coronary artery disease

Future cardiac events in patients with ischemic ECG changes during adenosine infusion as a myocardial stress agent and normal cardiac scan

BACKGROUND

We sought to determine the prognostic importance of adenosine-induced ischemic ECG changes in patients with normal single-photon emission computed tomography myocardial perfusion images (MPI).

PATIENTS AND METHODS

We carried out a retrospective analysis of 765 patients undergoing adenosine MPI between January 2013 and January 2015. Patients with baseline ECG abnormalities and/or abnormal scan were excluded.

RESULTS

Overall, 67 (8.7%) patients had ischemic ECG changes during adenosine infusion in the form of ST depression of 1 mm or more. Of these, 29 [43% (3.8% of all patients)] had normal MPI (positive ECG group). An age-matched and sex-matched group of 108 patients with normal MPI without ECG changes served as control participants (negative ECG group). During a mean follow-up duration of 33.3±6.1 months, patients in the positive ECG group did not have significantly more adverse cardiac events than those in the negative ECG group. One (0.9%) patient in the negative ECG group had a nonfatal myocardial infarction (0.7% annual event rate after a negative MPI). Also in this group, two (1.8%) patients admitted with a diagnosis of CAD where they have been ruled out by angiography. A fourth case in this, in the negative ECG group, was admitted because of heart failure that proved to be secondary to a pulmonary cause and not CAD. A case only in the positive ECG group was admitted as a CAD that was ruled out by coronary angiography.

CONCLUSION

Patients with normal myocardial perfusion scintigraphy in whom ST-segment depression develops during adenosine stress test appear to have no increased risk for future cardiac events compared with similar patients without ECG evidence of ischemia.

The prognostic value of regadenoson myocardial perfusion imaging

BACKGROUND

Regadenoson (REGA), a selective adenosine A2A receptor agonist, is the most widely used stress agent for SPECT myocardial perfusion imaging (MPI) in the United States. The diagnostic accuracy of REGA MPI is comparable to Adenosine MPI, but its prognostic value is not well defined.

METHODS

We categorized 1,400 patients (700 consecutive normal and 700 consecutive abnormal REGA-MPIs) into 4 groups based on the perfusion defect size using automated quantitative analysis: Group 1: normal perfusion; Group 2: <10% of left ventricle; Group 3: 10%-20%; Group 4: >20%. The primary outcome was a composite of cardiac death, myocardial infarction (MI), and late coronary revascularization (CR >90 days after MPI).

RESULTS

Of the 1,400 patients (42% male, 37% diabetes, 21% heart failure, 26% end-stage renal disease), the primary outcome occurred in 23% (17% cardiac death, 4% MI, 6% late CR) during 46 ± 18 months of follow-up and 8% had early CR (within 90 days of MPI). Early CR occurred in 0.4%, 9%, 17%, and 17% and the primary outcome in 10%, 27%, 31%, and 43% in Groups 1-4, respectively (P < .001 for both). In an adjusted Cox proportional model, the hazard ratio for the primary outcome was 2.68 (1.77-4.06), 3.32 (2.28-4.83), and 4.05 (2.78-5.91) for Groups 2-4 compared to Group 1.

CONCLUSION

REGA MPI provides powerful prognostic information that has important implications in patient management and can guide clinical practice.

Discrepancy between stress electrocardiographic changes and nuclear myocardial perfusion defects in the prognostic assessment of patients with chest pain

OBJECTIVES

The aim of the present study was to determine the long-term prognostic value provided by the exercise electrocardiographic (ECG) response to nuclear myocardial perfusion imaging (MPI) in the evaluation of patients with chest pain, focusing on patients with a discrepancy between the two tests.

METHODS

A total of 1460 consecutive patients (777 female; 62.6 ± 11.4 years) undergoing exercise myocardial single-photon emission computed tomography (SPECT) were included. The endpoint was the occurrence of acute coronary syndrome, heart failure or cardiac death during follow-up.

RESULTS

Ischemic ECG changes were observed during stress testing in 271 patients (18.5%) and 362 patients (24.7%) had positive (abnormal) exercise MPI results. There was a discrepancy between ECG and SPECT findings in 471 patients (32.2%). During the follow-up period (14.0-39.6 months), 224 patients (15.3%) presented cardiac events. The hazard ratios (HR) of ECG and MPI results to predict events were 1.506 (95% CI: 1.113-2.039) and 10.481 (95% CI: 7.799-14.080), respectively. In patients with negative MPI, the ECG response did not predict events (HR 1.214 [95% CI: 0.646-2.282]), the same as in patients with positive MPI (HR 1.203 [95% CI: 0.848-1.705]). Only in hypertensive patients with positive SPECT did the ECG show significant prognostic value (HR 1.937 [95% CI: 1.030-3.642]). In multivariate analysis, positive MPI proved an independent long-term prognostic factor (HR 10.536 [95% CI: 7.759-14.308]), but not ECG (HR 1.356 [95% CI: 0.994-1.850]).

CONCLUSION

MPI results (normal vs. abnormal) had strong predictive value and discrepant ECG results had no significant additive prognostic value.

Patients with adenosine-induced ST-segment depressions and normal myocardial perfusion imaging: cardiac outcomes at 24 months

BACKGROUND

The significance of ischemic ECG changes during adenosine infusion in patients with normal myocardial perfusion imaging (MPI) is controversial. We evaluated the prevalence of, and defined the predictors for, severe coronary artery disease (CAD) in patients with such discordant findings.

METHODS

The findings of 3700 adenosine MPI studies performed at our institution between June 2005 and March 2009 were reviewed.

RESULTS

Data for 76 patients who had not previously undergone coronary revascularization and who had sufficient follow-up were analyzed; 22 (29%) were referred for coronary angiography and 10 (13%) underwent revascularization. None had left main disease and only three (14%) had multivessel disease. Diabetes mellitus was more prevalent (70% vs. 23%; P = .010) and ischemic ST-segment depressions more often lasted >5 minutes (50% vs. 15%; P = 0.021) in patients undergoing revascularization. During a 24 ± 13 month follow-up period, there were no deaths or myocardial infarctions, while an eleventh patient underwent revascularization 19 months after MPI.

CONCLUSIONS

In the presence of normal MPI, the specificity of ischemic ECG changes during adenosine infusion for the detection of severe obstructive CAD is poor, although patients with multiple coronary risk factors, particularly diabetes mellitus, should undergo further investigation.

Integrated imaging of cardiac anatomy, physiology, and viability

Technologic developments in imaging will have a significant impact on cardiac imaging over the next decade. These advances will permit more detailed assessment of cardiac anatomy, complex assessment of cardiac physiology, and integration of anatomic and physiologic data. The distinction between anatomic and physiologic imaging is important. For assessing patients with known or suspected coronary artery disease, physiologic and anatomic imaging data are complementary. The strength of anatomic imaging rests in its ability to detect the presence of disease, whereas physiologic imaging techniques assess the impact of disease, such as whether a coronary atherosclerotic lesion limits myocardial blood flow. Research indicates that physiologic data are more prognostically important than anatomic data, but both may be important in patient management decisions. Integrated cardiac imaging is an evolving field, with many potential indications. These include assessment of coronary stenosis, myocardial viability, anatomic and physiologic characterization of atherosclerotic plaque, and advanced molecular imaging.

High-sensitivity C-reactive protein and silent myocardial ischemia in Chinese with type 2 diabetes mellitus

Coronary artery disease (CAD) is a major cause of morbidity and mortality in patients with type 2 diabetes mellitus. When diabetes exists in patients with established CAD, absolute risk for future events is very high. Diabetic patients often have severe, yet asymptomatic, CAD. Although high-sensitivity C-reactive protein (hsCRP) is a strong independent risk factor for cardiovascular events, there is an unclear association between it and silent myocardial ischemia in diabetic patients. In this study, we assess the relationship between hsCRP and silent myocardial ischemia in Chinese with type 2 diabetes mellitus. We designed a cross-sectional study with 225 asymptomatic diabetic patients having no known CAD. Ischemia was assessed by myocardial perfusion imaging. A total of 109 patients (48.4%) was found to have silent myocardial ischemia. Logistic regression analysis revealed age (odds ratio = 4.01, P = .002) (95% confidence interval, 1.98-7.44) and hsCRP (odds ratio = 2.58, P = .005) (95% confidence interval, 1.33-5.01) to be associated with greater risk of silent myocardial ischemia. Using the American Diabetes Association screening guidelines to evaluate risk, we found silent myocardial ischemia to be equally distributed between diabetic patients with 2 or more cardiac risk factors and those with less than 2 risk factors. Twenty-seven (24.8%) patients with silent myocardial ischemia were missed when the American Diabetes Association guidelines were used alone. High-sensitivity C-reactive protein was associated with silent myocardial ischemia in our study. High-sensitivity C-reactive protein might help detect silent myocardial ischemia in diabetic Chinese who may need aggressive treatment to reduce future CAD morbidity and mortality in Taiwan.

Outcome of patients with adenosine-induced ST-segment depression but with normal perfusion on tomographic imaging

Most patients with ST depression during adenosine infusion have reversible perfusion defects by single-photon emission computed tomographic (SPECT) perfusion images. Occasionally ST depression is observed in the setting of normal perfusion images. The outcome of such patients is controversial. We identified 65 patients who underwent gated SPECT perfusion imaging with adenosine as the stress agent. These patients were selected based on the following criteria: none had previous myocardial infarction or coronary revascularization, all were in sinus rhythm, and none had left bundle branch block. The 65 patients had normal SPECT images but ischemic ST response (>or=1 mm ST depression). There were 52 women and 13 men who were 66 +/- 13 years of age. History of diabetes mellitus was present in 16 patients (25%) and hypertension in 48 patients (74%). At a mean follow-up of 24 months, there were no cardiac deaths or myocardial infarctions, and there were 6 coronary revascularization procedures (2 coronary artery bypass graftings and 4 coronary stentings of 1-vessel coronary disease). One patient died of cancer. In conclusion, patients with no previous myocardial infarction or coronary revascularization who have normal SPECT images have a benign outcome despite the presence of ST depression (0% for death or myocardial infarction and 4.6%/year for coronary revascularization). Balanced ischemia could not be a common cause for discordant perfusion and ST response.

Systematic review of the prognostic effectiveness of SPECT myocardial perfusion scintigraphy in patients with suspected or known coronary artery disease and following myocardial infarction

OBJECTIVES

In patients with suspected or known coronary artery disease (CAD), or following myocardial infarction (MI), assessing the degree of ischaemia is important from a prognostic and therapeutic point of view. Single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy (MPS) is a non-invasive technique that allows the presence, location and extent of ischaemia to be determined. The aim of this systematic review was to assess the prognostic effectiveness of SPECT MPS.

METHODS

We sought prognostic studies involving SPECT, exercise tolerance testing (ETT) and/or coronary angiography (CA) in people with suspected or known CAD, or following MI. Outcomes included cardiac death, non-fatal MI and revascularization. We searched the following databases: MEDLINE, PREMEDLINE, EMBASE, BIOSIS, Science Citation Index, the Cochrane Library, the Health Management Information Consortium and the Health Technology Assessment Database.

RESULTS

Twenty-one observational studies enrolling 53,762 people reported the general prognostic value of SPECT MPS. In multivariate analysis, SPECT MPS variables yielded both independent and incremental value to combinations of clinical, ETT and angiographic variables in predicting cardiac death or non-fatal MI. Three comparative studies reported lower revascularization rates following a SPECT MPS-CA strategy (6-21%) compared with direct CA (16-44%). Four observational studies enrolling 2106 people reported the prognostic value of SPECT for patients following MI. In multivariate analysis including clinical history, ETT, SPECT MPS and angiographic variables, strategies involving SPECT MPS provided independent and incremental prognostic performance in predicting future cardiac events.

CONCLUSIONS

SPECT MPS provides important additional information to that from ETT and/or CA that helps to risk-stratify patients with suspected or known CAD or following MI, enabling them to be managed more appropriately. Increasing the use of strategies involving SPECT MPS may identify lower risk patients for whom invasive CA might be avoided.

Role of noninvasive testing in the clinical evaluation of women with suspected coronary artery disease: Consensus statement from the Cardiac Imaging Committee, Council on Clinical Cardiology, and the Cardiovascular Imaging and Intervention Committee, Council on Cardiovascular Radiology and Intervention, American Heart Association

Cardiovascular disease is the leading cause of mortality for women in the United States. Coronary heart disease, which includes coronary atherosclerotic disease, myocardial infarction, acute coronary syndromes, and angina, is the largest subset of this mortality, with >240,000 women dying annually from the disease. Atherosclerotic coronary artery disease (CAD) is the focus of this consensus statement. Research continues to report underrecognition and underdiagnosis of CAD as contributory to high mortality rates in women. Timely and accurate diagnosis can significantly reduce CAD mortality for women; indeed, once the diagnosis is made, it does appear that current treatments are equally effective at reducing risk in both women and men. As such, noninvasive diagnostic and prognostic testing offers the potential to identify women at increased CAD risk as the basis for instituting preventive and therapeutic interventions. Nevertheless, the recent evidence-based practice program report from the Agency for Healthcare Research and Quality noted the paucity of women enrolled in diagnostic research studies. Consequently, much of the evidence supporting contemporary recommendations for noninvasive diagnostic studies in women is extrapolated from studies conducted predominantly in cohorts of middle-aged men. The majority of diagnostic and prognostic evidence in cardiac imaging in women and men has been derived from observational registries and referral populations that are affected by selection and other biases. Thus, a better understanding of the potential impact of sex differences on noninvasive cardiac testing in women may greatly improve clinical decision making. This consensus statement provides a synopsis of available evidence on the role of the exercise ECG and cardiac imaging modalities, both those in common use as well as developing technologies that may add clinical value to the diagnosis and risk assessment of the symptomatic and asymptomatic woman with suspected CAD.

Comparison of risk stratification with pharmacologic and exercise stress myocardial perfusion imaging: a meta-analysis

BACKGROUND

Although pharmacologic stress myocardial perfusion imaging (MPI) and exercise stress MPI have comparable diagnostic accuracy, their comparative value for risk stratification of patients with known or suspected coronary disease is not known.

METHODS AND RESULTS

The data of 14,918 patients were combined from 24 studies evaluating prognosis in patients undergoing either pharmacologic stress or exercise stress MPI. Studies were included if a 2 x 2 table for hard cardiac events (cardiac death and myocardial infarction [MI]) could be constructed from the data available. Excluded were studies performed for post-MI, post-revascularization, or preoperative risk stratification. A weighted t test was used to compare the cardiac events, and a random effects model was used to calculate summary odds ratios. Summary odds ratios for hard cardiac events were similar for pharmacologic stress and exercise stress MPI. Summary receiver operating characteristic curves also showed no difference in discriminatory power between the stressors. The cardiac event rates were significantly higher with normal and abnormal test results with pharmacologic stress MPI than with exercise stress MPI (1.78% vs 0.65% [P < .001] for normal results and 9.98% vs 4.3% [P < .001] for abnormal results). Subgroup analysis revealed that both cardiac death and nonfatal MI were significantly higher with pharmacologic stress MPI. Patients undergoing pharmacologic stress MPI had a significantly higher prevalence of poor prognostic factors, and meta-regression revealed that exercise capacity was the single most important predictor of cardiac events.

CONCLUSIONS

This meta-analysis shows that exercise stress MPI and pharmacologic stress MPI are comparable in their ability to risk-stratify patients. However, patients undergoing pharmacologic stress studies are at a higher risk for subsequent cardiac events. This is true even for those with normal perfusion imaging results.

Myocardial perfusion scintigraphy: the evidence

This review summarises the evidence for the role of myocardial perfusion scintigraphy (MPS) in patients with known or suspected coronary artery disease. It is the product of a consensus conference organised by the British Cardiac Society, the British Nuclear Cardiology Society and the British Nuclear Medicine Society and is endorsed by the Royal College of Physicians of London and the Royal College of Radiologists. It was used to inform the UK National Institute of Clinical Excellence in their appraisal of MPS in patients with chest pain and myocardial infarction. MPS is a well-established, non-invasive imaging technique with a large body of evidence to support its effectiveness in the diagnosis and management of angina and myocardial infarction. It is more accurate than the exercise ECG in detecting myocardial ischaemia and it is the single most powerful technique for predicting future coronary events. The high diagnostic accuracy of MPS allows reliable risk stratification and guides the selection of patients for further interventions, such as revascularisation. This in turn allows more appropriate utilisation of resources, with the potential for both improved clinical outcomes and greater cost-effectiveness. Evidence from modelling and observational studies supports the enhanced cost-effectiveness associated with MPS use. In patients presenting with stable or acute chest pain, strategies of investigation involving MPS are more cost-effective than those not using the technique. MPS also has particular advantages over alternative techniques in the management of a number of patient subgroups, including women, the elderly and those with diabetes, and its use will have a favourable impact on cost-effectiveness in these groups. MPS is already an integral part of many clinical guidelines for the investigation and management of angina and myocardial infarction. However, the technique is underutilised in the UK, as judged by the inappropriately long waiting times and by comparison with the numbers of revascularisations and coronary angiograms performed. Furthermore, MPS activity levels in this country fall far short of those in comparable European countries, with about half as many scans being undertaken per year. Currently, the number of MPS studies performed annually in the UK is 1,200/million population/year. We estimate the real need to be 4,000/million/year. The current average waiting time is 20 weeks and we recommend that clinically appropriate upper limits of waiting time are 6 weeks for routine studies and 1 week for urgent studies.

The clinical role of stress myocardial perfusion imaging in women with suspected coronary artery disease

Cardiovascular disease remains the number one cause of mortality for women in the United States, with coronary artery disease (CAD) accounting for 54% of all cardiovascular deaths. CAD claims the lives of more than 250,000 women each year and is therefore the single largest killer of American women. For several decades, the under-representation of women in clinical trials led to both a lack of available sex-specific evidence and a generalized misconception that CAD was a "man's disease." In actuality, not only are women vulnerable to CAD, they typically develop it 10 to 15 years later than men. Furthermore, sex differences exist in the mortality rates of women and men with CAD, such that once CAD is present in women, they have worse outcomes than their male counterparts. Consequently, early and accurate diagnosis of CAD is crucial for reducing mortality rates in women. Stress myocardial perfusion imaging (MPI) using contemporary techniques has been shown to have significant value in the diagnosis and prognosis of CAD in women. In the risk assessment of women with an intermediate clinical pretest likelihood of CAD, using MPI with exercise or pharmacologic stress has been shown to add incremental value to clinical variables or exercise electrocardiogram stress testing alone. This review discusses the clinical role of stress MPI in the management of women with suspected CAD.

Stress Myocardial Perfusion Imaging in the Diagnosis and Prognosis of Women with Suspected Coronary Artery Disease

Coronary artery disease is the single largest killer of women in the United States and claims the lives of more than 250,000 women each year. For several decades, there was the misperception that coronary artery disease was a "man's disease." The fact is that women are indeed vulnerable to coronary artery disease; however, they typically develop the disease 10 to 15 years later than men. Once coronary artery disease is evident, women have worse outcomes as compared with men.Therefore, early and accurate diagnosis of coronary artery disease is crucial for reducing heart disease mortality in women. Stress myocardial perfusion imaging using contemporary techniques has been shown to have significant value in the diagnosis and prognosis of coronary artery disease in women. Myocardial perfusion imaging with exercise or pharmacologic stress has been shown to add incremental value to the use of clinical variables or exercise electrocardiogram stress testing alone in the risk stratification of women with an intermediate clinical pretest likelihood of coronary artery disease. This review provides an overview of the role of stress myocardial perfusion imaging in the clinical evaluation of women with suspected coronary artery disease.

Predictive value of myocardial tomoscintigraphy in asymptomatic diabetic patients after percutaneous coronary intervention

OBJECTIVE

This study was designed to assess the prognostic value of myocardial tomoscintigraphy perfusion imaging after percutaneous coronary intervention (PCI) in asymptomatic diabetic patients.

METHODS

One hundred and fourteen diabetic patients were followed up during 27+/-16 (mean+/-SD) months after the myocardial tomoscintigraphy. PCI-related events were studied after myocardial tomoscintigraphy stress testing and included major cardiac events (MACE) (cardiovascular death, myocardial infarction) and revascularization (bypass surgery or new PCI). Stress myocardial tomoscintigraphy imaging was performed 5+/-5 months after PCI and ischemia was considered as present if at least 2 contiguous segments were showing reversible defects.

RESULTS

Persistent silent ischemia was found in 49/114 (43%) patients. No difference was observed between the two groups for MACE: four among the 65 (6%) non ischemic patients versus 2 among the 49 (4%) ischemic patients (NS). In contrast, 15 (31%) among the ischemic patients and 4 (6%) among the non ischemic patients underwent iterative revascularization (p<0.01). The relative risk of revascularization for patients with significant ischemia was 5.5 versus non ischemic patients (p<0.001).

CONCLUSION

After PCI, in asymptomatic diabetic patients followed by myocardial tomoscintigraphy a high frequency of persistent silent ischemia was found and associated with a high risk for repeat interventional procedure, although no increase in major cardiac events was observed.

Pharmacologic radionuclide myocardial perfusion imaging

Pharmacologic stress testing with myocardial perfusion imaging has enabled patients who cannot complete adequate exercise to undergo diagnostic and prognostic evaluation for coronary artery disease. Pharmacologic stress agents belong to two groups: vasodilators (such as adenosine and dipyridamole), and inotropes (such as dobutamine). All have similar sensitivity (89%-91%) and specificity (78%-86%) for the diagnosis of coronary disease. For risk stratification, the risk of future cardiac events is related to the extent and severity of perfusion abnormalities. Pharmacologic stress testing permits risk stratification as early as 1 to 4 days following an acute myocardial infarction, and is superior to exercise stress testing in this regard. Similarly, it identifies patients at high risk for perioperative cardiac events prior to noncardiac surgery. This review summarizes the current evidence available regarding the diagnostic and prognostic use of pharmacologic stress testing.

Cardiac nuclear medicine in monitoring patients with coronary heart disease

Patient monitoring is a major indication for cardiac nuclear medicine procedures. Stress myocardial perfusion scintigraphy was initially used for diagnosis, but monitoring patients with coronary artery disease has become more common. Stress myocardial perfusion scintigraphy has been shown to provide a considerable amount of incremental prognostic information, which may be useful in selecting patients for therapy. In patients being considered for revascularization, fluorodeoxyglucose can be used to identify regions of dysfunctional but viable myocardium, even within regions that show fixed defects on stress perfusion imaging. It can be used to select a group of patients who will improve function with revascularization and who may have an improved outcome. Thus, cardiac nuclear medicine plays a pivotal role in monitoring patients with coronary artery disease.

Comparative prognostic value of automatic quantitative analysis versus semiquantitative visual analysis of exercise myocardial perfusion single-photon emission computed tomography

OBJECTIVES

The purpose of this study was to determine the prognostic value of automatic quantitative analysis in exercise dual-isotope myocardial perfusion single-photon emission computed tomography (SPECT) and to compare the prognostic value of quantitative analysis to semiquantitative visual SPECT analysis.

BACKGROUND

Extent, severity and reversibility of exercise myocardial perfusion defects have been shown to correlate with prognosis. However, most studies examining the prognostic value of SPECT in chronic coronary artery disease (CAD) have been based on visual analysis by experts.

METHODS

We studied 1,043 consecutive patients with known or suspected CAD who underwent rest Tl-201/exercise Tc-99m sestamibi dual-isotope myocardial perfusion SPECT and were followed up for at least 1 year (mean 20.0+/-3.7 months). After censoring 59 patients with early coronary artery bypass grafting or percutaneous transluminal coronary angioplasty, <60 days after nuclear testing, the final population consisted of 984 patients (36% women, mean age 63+/-12 years).

RESULTS

During the follow-up period, 28 hard events (14 cardiac deaths, 14 nonfatal myocardial infarctions) occurred. Patients with higher defect extent (>10%), severity (>150) and reversibility (>5%) by quantitative SPECT defect analysis, as well as those with an abnormal scan (>2 abnormal segments, summed stress score >4 and summed difference score >2) by semiquantitative visual SPECT analysis, had a significantly higher hard event rate compared to patients with a normal scan (p < 0.001). With both visual and quantitative analyses, hard event rates of approximately 1% with normal scans and 5% with abnormal scans (p > 0.05) were observed over the 20-month follow-up period. A Cox proportional hazards regression model showed that chi-square increased similarly with the addition of quantitative defect extent and visual summed stress score variables after considering both clinical and exercise variables (improvement chi-square = 11 for both, p < 0.0007). There were no significant differences in the areas under receiver operating characteristic curves between quantitative and visual analysis (p > 0.70). Linear regression analysis also indicated that quantitative assessments correlated well with visual semiquantitative assessments.

CONCLUSIONS

The findings of this study indicate that automatic quantitative analysis of exercise stress myocardial perfusion SPECT is similar to semiquantitative expert visual analysis for prognostic stratification. These findings may be of particular clinical importance in laboratories with less experienced visual interpreters.

Independent and incremental prognostic value of exercise thallium single-photon emission computed tomographic imaging in women

BACKGROUND

This study examined the independent and incremental prognostic value of exercise thallium single-photon emission computed tomographic imaging in 212 women who also underwent coronary angiography.

METHODS AND RESULTS

The left ventricular ejection fraction was normal (65% +/- 15%). During a mean follow-up of 40 months, 27 women had events (cardiac death or nonfatal myocardial infarction). Univariate Cox survival analysis showed several variables to be different between patients with events and those without events: age, exercise heart rate, the extent of coronary artery disease, reversible thallium defects, number of segments with reversible abnormality, and size of perfusion abnormality. Multivariate survival analysis showed that a large perfusion abnormality and age were the independent predictors of events. Actuarial life-table analysis showed that women with a large thallium abnormality (> or = 15% of the myocardium) had significantly worse event-free survival rates than had women with no or small abnormalities (Mantel-Cox statistic = 16; p = 0.0001).

CONCLUSIONS

Thus exercise thallium-201 single-photon emission computed tomographic imaging provides independent and incremental prognostic information to clinical, exercise, and coronary angiographic results in women. The presence of a larger thallium abnormality identifies women at high risk of cardiac events.