Potential of non-contrast stress T1 mapping for the assessment of myocardial injury in hypertrophic cardiomyopathy

BACKGROUND

Ischemia of the hypertrophied myocardium due to microvascular dysfunction is related to a worse prognosis in hypertrophic cardiomyopathy (HCM). Stress and rest T1 mapping without contrast agents can be used to assess myocardial blood flow. Herein, we evaluated the potential of non-contrast stress T1 mapping in assessing myocardial injury in patients with HCM.

METHODS

Forty-five consecutive subjects (31 HCM patients and 14 control subjects) underwent cardiac magnetic resonance (CMR) at 3T, including cine imaging, T1 mapping at rest and during adenosine triphosphate (ATP) stress, late gadolinium enhancement (LGE), and phase-contrast (PC) cine imaging of coronary sinus flow at rest and during stress to assess coronary flow reserve (CFR). PC cine imaging was performed on 25 subjects (17 patients with HCM and 8 control subjects). Native T1 values at rest and during stress were measured using the 16-segment model, and T1 reactivity was defined as the change in T1 values from rest to stress.

RESULTS

ATP stress induced a significant increase in native T1 values in both the HCM and control groups (HCM: p < 0.001, control: p = 0.002). T1 reactivity in the HCM group was significantly lower than that in the control group (4.2 ± 0.3% vs. 5.6 ± 0.5%, p = 0.044). On univariate analysis, T1 reactivity correlated with native T1 values at rest, left ventricular mass index, and CFR. Multiple linear regression analysis demonstrated that only CFR was independently correlated with T1 reactivity (β = 0.449; 95% confidence interval, 0.048-0.932; p = 0.032). Furthermore, segmental analysis showed decreased T1 reactivity in the hypertrophied myocardium and the non-hypertrophied myocardium with LGE in the HCM group.

CONCLUSIONS

T1 reactivity was lower in the hypertrophied myocardium and LGE-positive myocardium compared to non-injured myocardium. Non-contrast stress T1 mapping is a promising CMR method for assessing myocardial injury in patients with HCM. Trial registration Retrospectively registered.

Prognostic Implications of Sarcoidosis Granulomas - Insights From the Multicenter Registry, the Japanese Cardiac Sarcoidosis Prognostic Study

Background: Definitions of cardiac sarcoidosis (CS) differ among guidelines. Any systemic histological finding of CS is essential for the diagnosis of CS in the 2014 Heart Rhythm Society statement, but not necessary in the Japanese Circulation Society 2016 guidelines. This study aimed to reveal the differences in outcomes by comparing 2 groups, namely CS patients with or without systemic histologically proven granuloma. Methods and Results: This study retrospectively included 231 consecutive patients with CS. CS with granulomas in ≥1 organs was diagnosed in 131 patients (Group G), whereas CS without any granulomas was diagnosed in the remaining 100 patients (Group NG). Left ventricular ejection fraction (LVEF) was significantly reduced in Group NG compared with Group G (44±13% vs. 50±16%, respectively; P=0.001). However, Kaplan-Meier curves showed that major adverse cardiovascular events (MACE)-free survival outcomes were comparable between the 2 groups (log-rank P=0.167). Univariable analyses showed that significant predictors of MACE were Groups G/NG, histological CS, LVEF, and high B-type natriuretic peptide (BNP) or N-terminal pro BNP concentrations, but none of these was significant in multivariable analyses. Conclusions: Overall risks of MACE were similar between the 2 groups despite different manifestations in cardiac dysfunction. The data not only validate the prognostic value of non-invasive diagnosis of CS, but also show the need for careful observation and therapeutic strategy in patients with CS without any granuloma.

Multicenter Registry in the Japanese Cardiac Sarcoidosis Prognostic (J-CASP) Study: Baseline Characteristics and Validation of the Non-invasive Approach Using 18F-FDG PET

Background: Recent advances in cardiac modalities contribute to the guidelines on the diagnosis of cardiac sarcoidosis (CS) updated by the Japanese Circulation Society. The multicenter registry, Japanese Cardiac Sarcoidosis Prognostic (J-CASP) study tried to reveal recent trends of diagnosis and outcomes in CS patients and to validate the non-invasive diagnostic approach, including cardiac ¹⁸F-fluorodeoxyglucose (FDG) study. Methods/results: Databases from 12 hospitals consisting of 231 CS patients (mean age, 64 years; female, 65%; LV ejection fraction, 47%) diagnosed by the guidelines with FDG positron emission tomography (PET) study were integrated to compile clinical information on the diagnostic criteria and outcomes. Cardiac ¹⁸F-FDG uptake and magnetic resonance imaging (CMR) was positive identically in the histology-proven and clinically-diagnosed groups. The histology-proven group more frequently had reduce LV ejection fraction, myocardial perfusion abnormality and low-grade electrocardiogram (ECG) abnormality (P=0.003 to 0.016) than did the clinical group. During a 45-month period, the histology-proven group more frequently underwent appropriate implantable cardioverter-defibrillator (ICD) treatment (14% versus 4%, P=0.013) and new electronic device implantation (30% versus 12%, P=0.007) than did clinical group, respectively. There, however, was no difference in all-cause or cardiac mortality or in new hospitalization due to heart failure progression between them. Conclusion: The J-CASP registry demonstrated the rationale and clinical efficacies of non-invasive approach using advanced cardiac imaging modalities in the diagnosis of CS even when histological data were available.

Association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan

BACKGROUND

There is an ongoing controversy regarding the necessity of single-photon emission computed tomography (SPECT) for patients with ischemic heart diseases after the publication of the results of the ISCHEMIA trial. We aimed to evaluate the association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan.

METHODS

From the data of 2780 patients with stable angina who were enrolled prospectively between January 2006 and March 2008 in Japan and had undergone physician-referrednon-invasive imaging tests (Japanese Coronary-Angiography or Myocardial Imaging for Angina Pectoris Study), 1205 patients managed with SPECT were stratified by 10% myocardial ischemia. Major adverse cardiac events (MACEs), including death, myocardial infarction, hospitalization for heart failure, and late revascularization, were followed-up for 1year.

RESULTS

Patients with ≥10% myocardial ischemia (n=173) were less likely to be women than patients with <10% myocardial ischemia (n=1032) and had a significantly higher 1-year cumulative incidence of MACEs (6.9% vs. 1.8%, p<0.0001). After adjusting for confounders, the risk of ≥10% myocardial ischemia relative to <10% myocardial ischemia for MACEs remained significant [adjusted hazard ratio (95% confidence interval), 2.40 (1.09-5.26), p=0.029]. After adjusting including treatments, the risk of MACEs became insignificant between the ≥10% myocardial ischemia group and the <10% myocardial ischemia group [adjusted hazard ratio (95% confidence interval), 1.04 (0.45-2.45), p=0.92].

CONCLUSION

The presence of ≥10% myocardial ischemia at diagnosis was significantly associated with the 1-year risk for MACEs in Japanese patients with suspected coronary artery disease.

Performance of Hybrid Imaging in the Diagnosis of Coronary Artery Disease

Single-photon emission computed tomography (SPECT) and computed tomography coronary angiography (CTCA) are usually performed independently in patients with suspected coronary artery disease. We assessed the hypothesis that hybrid SPECT/CTCA imaging results in higher diagnostic accuracy than either method alone, particularly in cases presenting with high levels of coronary calcification. A total of 243 major coronary vessels in 81 patients with known or suspected coronary artery disease were screened using SPECT with semiconductor detectors and CTCA with 256-detector row computed tomography. Patients who were diagnosed with myocardial ischemia underwent coronary angiography. Coronary angiography results were defined as positive for stenosis when the stenosis diameter was >70% or fractional flow reserve was <0.8. These data were then compared with a fused image of the SPECT and CTCA datasets generated using a dedicated workstation. To detect significant coronary artery stenosis, the respective sensitivity, specificity, and accuracy were 73%, 61%, and 67% with SPECT alone, 96%, 44%, and 67% with CTCA alone, and 95%, 75%, and 84% with hybrid imaging. Moreover, hybrid imaging allowed the accurate diagnosis of 47 vessels with severe calcification that CTCA alone could not evaluate correctly. Hybrid imaging shows greater diagnostic accuracy than single-modality evaluation through more comprehensive information on potential coronary stenosis and its hemodynamic significance.

Diagnostic value of simultaneous 99mTc-sestamibi/123I-BMIPP imaging parameters for predicting the improvement of left ventricular wall motion after acute myocardial infarction using CZT SPECT system

Background

Although the presence of 99mTc-sestamibi/123I-BMIPP-mismatch, the reverse redistribution (RR) of 99mTc-sestamibi and RR of 123I-BMIPP in patients with acute myocardial infarction (AMI) are known to significant markers for predicting the improvement of LV wall motion in the infarcted territory in chronic phase, few studies were performed to analyze them by simultaneous dual-isotope imaging using cadmium-zinc-telluride (CZT) SPECT system.

Purpose

The purpose of this study was to evaluate whether the presence of 99mTc-sestamibi/123I-BMIPP-mismatch or RR of 99mTc-sestamibi, RR of 123I-BMIPP make better prediction of the improvement of LV wall motion in the infarcted territory.

Methods

We evaluated 42 consecutive patients with AMI who had undergone both dual-isotope SPECT in acute phase and stress myocardial SPECT using 99mTc-tracers in chronic phase by Discovery NM530c. The presence of 99mTc-sestamibi/123I-BMIPP-mismatch, RR of 99mTc-sestamibi and RR of 123I-BMIPP were determined using traditional definition. The improvement of LV wall motion in the infarcted territory from acute phase to chronic phase was assessed using QGS.

Results

Of 42 patients, the improvement of LV wall motion in the infarcted territory from acute phase to chronic phase was found in 29 patients. The presence of 99mTc-sestamibi/123I-BMIPP-mismatch and RR of 99mTc-sestamibi and RR of 123I-BMIPP were significantly linked to predict the improvement of LV wall motion (p=0.0001, p=0.0001 and p=0.002, respectively). To predict the improvement of LV wall motion in the infarcted territory in chronic phase, the presence of 99mTc-sestamibi/123I-BMIPP-mismatch showed sensitivity of 93%, specificity of 85% and accuracy of 91%, while RR of 99mTc-sestamibi and RR of 123I-BMIPP had sensitivities of 72%, 48%, specificities of 85%, 100% and accuracies of 76%, 64%, respectively. The multivariate discriminant analysis revealed that the combination of 99mTc-sestamibi/123I-BMIPP-mismatch, RR of 99mTc-sestamibi and RR of 123I-BMIPP best predicted the improvement of LV wall motion in the infarcted territory in chronic phase with sensitivity of 93%, specificity of 85% and accuracy of 91% (chi-square=40.6), compared with RR of 99mTc-sestamibi and RR of 123I-BMIPP only (sensitivity 79%, specificity 85% and accuracy of 81%, chi-square=16.9).

Conclusions

The addition of 99mTc-sestamibi/123I-BMIPP-mismatch on RR of 99mTc-sestamibi and RR of 123I-BMIPP in patients with AMI, help better predict the improvement of LV wall motion in the infarcted territory in chronic phase.

Funding Acknowledgement

Type of funding sources: None.

Association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan: a cohort study

Background

There is an ongoing controversy regarding the necessity of single-photon emission computed tomography (SPECT) for patients with ischemic heart diseases after the publication of the results of the ISCHEMIA trial.

Purpose

We aimed to evaluate the association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan.

Methods

From the data of 2780 patients with stable angina who were enrolled prospectively between January 2006 and March 2008 in Japan and had undergone physician-referred non-invasive imaging tests, 1205 patients managed with SPECT were stratified by 10% myocardial ischemia. Major adverse cardiac events (MACEs), including death, myocardial infarction, hospitalization for heart failure, and late revascularization, were followed-up for 1 year.

Results

Patients with ≥10% myocardial ischemia (n=173) were older than patients with &lt;10% myocardial ischemia (n=1032) and had a significantly higher 1-year cumulative incidence of MACEs (9.1% vs. 1.2%, P&lt;0.0001). After adjusting for confounders, the risk of ≥10% myocardial ischemia relative to &lt;10% myocardial ischemia for MACEs remained significant (adjusted hazard ratio [95% confidence interval], 2.40 [1.09–5.26], P=0.029).

Conclusion

The presence of ≥10% myocardial ischemia was significantly associated with the 1-year risk for MACEs in Japanese patients with suspected coronary artery disease.

Funding Acknowledgement

Type of funding sources: None. Study flowchartOutcomes

Prediction of the improvement of left ventricular wall motion after acute myocardial infarction by simultaneous dual-isotope imaging with 99mTc-sestamibi/123I-BMIPP using cadmium-zinc-telluride SPECT

Background/Introduction

Although both the presence of 99mTc-sestamibi/123I-BMIPP mismatch and the reverse redistribution of 99mTc-sestamibi in patients with acute myocardial infarction (AMI) are known to significant markers for predicting the improvement of left ventricular (LV) wall motion in the infarcted territory in chronic phase, few studies evaluated them by simultaneous dual-isotope (99mTc-sestamibi/123I-BMIPP) imaging using cadmium-zinc-telluride (CZT) SPECT system.

Purpose

The purpose of this study was to evaluate whether the presence of 99mTc-sestamibi/123I-BMIPP mismatch or the reverse redistribution of 99mTc-sestamibi make better prediction of the improvement of LV wall motion in the infarcted territory.

Methods

We evaluated 30 consecutive patients with AMI who had undergone both dual-isotope (99mTc-sestamibi/123I-BMIPP) SPECT in acute phase and stress myocardial SPECT using 99mTc-tracers in chronic phase by Discovery NM530c. Both 99mTc-sestamibi/123I-BMIPP mismatch and reverse redistribution of 99mTc-sestamibi were determined using traditional definition. The improvement of LV wall motion in the infarcted territory from acute phase to chronic phase was assessed using QGS.

Results

Of 30 patients, the improvement of LV wall motion in the infarcted territory from acute phase to chronic phase was found in 20 patients. Both the presence of 99mTc-sestamibi/123I-BMIPP mismatch and reverse redistribution of 99mTc-sestamibi were significantly linked to predict the improvement of LV wall motion (p=0.0001, p=0.011, respectively). The respective sensitivities, specificities and accuracies in the prediction of the improvement of LV wall motion in the infarcted territory were 90%, 90% and 90% with 99mTc-sestamibi/123I-BMIPP mismatch, and 60%, 90%, 70% with reverse redistribution of 99mTc-sestamibi.

Conclusions

In the simultaneous 99mTc-sestamibi/123I-BMIPP dual-isotope imaging using CZT SPECT system, both the presence of 99mTc-sestamibi/123I-BMIPP mismatch and the reverse redistribution of 99mTc-sestamibi in acute phase are useful for predicting the improvement of LV wall motion in chronic phase, but the presence of 99mTc-sestamibi/123I-BMIPP mismatch is superior to the reverse redistribution of 99mTc-sestamibi for it.

Funding Acknowledgement

Type of funding source: None

Prediction of myocardial viability in chronic phase in patients with acute myocardial infarction by simultaneous dual-isotope imaging with 99mTc-sestamibi/123I-BMIPP SPECT using CZT camera system

Objectives

The objective of this study was to determine the optimal cut-off value of % uptake of simultaneous dual-isotope (99mTc-sestamibi/123I-BMIPP) SPECT in patients with acute myocardial infarction (AMI) for prediction of myocardial viability in chronic phase.

Methods

We evaluated 30 consecutive patients with AMI who had undergone both dual-SPECT in acute phase and stress myocardial SPECT using 99mTc-tracers in chronic phase by Discovery NM530c. Regional % uptake with a 17-segment model was obtained using QPS software. The presence of myocardial viability was defined when regional % uptake ≥50% in 99mTc SPECT at rest in chronic phase was observed. Receiver operating characteristic (ROC) curves were analyzed to determine the optimal cutoff values of regional % uptake in both left anterior descending artery (LAD) territory and non-LAD coronary territory in acute phase to predict the myocardial viability in chronic phase.

Results

The cutoff values for prediction of viable myocardium were %uptake ≥47% for 99mTc-sestamibi, %uptake ≥31% for 123I-BMIPP in acute phase in LAD territory and %uptake ≥52% for 99mTc-sestamibi, %uptake ≥48% for 123I-BMIPP in non-LAD territory. The respective sensitivities, specificities and the area under the ROC curve (AUC) values in the prediction of myocardial viability were 92%, 92% and 0.94 with 99mTc-sestamibi, 90%, 85%, 0.92 with 123I-BMIPP in LAD territory, and 81%, 93% and 0.92 with 99mTc-sestamibi, 81%, 90%, 0.92 with 123I-BMIPP in non-LAD territory. There were no significant differences in AUC values between 99mTc-sestamibi and 123I-BMIPP in both LAD territory and non-LAD coronary territory.

Conclusions

In the simultaneous 99mTc-sestamibi/123I-BMIPP dual-isotope imaging in patients with AMI, these results suggest that not only 99mTc-sestamibi SPECT, but also 123I-BMIPP SPECT may be possible to predict the presence of myocardial viability in chronic phase. But it should be noted that the optimal cutoff values of regional % uptake in acute phase to predict the myocardial viability may differ for LAD territory and non-LAD coronary territory.

Funding Acknowledgement

Type of funding source: None

Association of coronary revascularisation after physician-referred non-invasive diagnostic imaging tests with outcomes in patients with suspected coronary artery disease: a post hoc subgroup analysis

OBJECTIVE

We aimed to evaluate the association of the prognostic impact of coronary revascularisation with physician-referred non-invasive diagnostic imaging tests (single photon emission CT (SPECT) vs coronary CT angiography) for coronary artery disease.

DESIGN

A post hoc analysis of a subgroup from the patient cohort recruited for the Japanese Coronary-Angiography or Myocardial Imaging for Angina Pectoris Study.

SETTING

Multiple centres in Japan.

PARTICIPANTS

From the data of 2780 patients with stable angina, enrolled prospectively between January 2006 and March 2008 in Japan, who had undergone physician-referred non-invasive imaging tests, 1205 patients with SPECT as an initial strategy and 625 with CT as an initial strategy were analysed. We assessed the effect of revascularisation (within 90 days) in each diagnostic imaging stratum and the interaction between the two strata.

PRIMARY AND SECONDARY OUTCOME MEASURES

Major adverse cardiac events (MACEs), including death, myocardial infarction, hospitalisation for heart failure and late revascularisation, were followed up for 1 year. The χ² test, Student's t-test, Kaplan-Meier analysis, log-rank test and multivariable Cox proportional hazard model were used in data analysis.

RESULTS

A total of 210 (17.4%) patients in the SPECT stratum and 149 (23.8%) in the CT stratum underwent revascularisation. Although in each stratum, the cumulative 1 year incidence of MACEs was significantly higher in patients who underwent revascularisation than in those who did not (SPECT stratum: 9.1 vs 1.2%, log-rank p<0.0001; CT stratum: 6.1 vs 0.8%, log-rank p=0.0001), there was no interaction between the risk of revascularisation and the imaging strata (SPECT stratum: adjusted HR (95% CI), 4.25 (1.86-9.72); CT stratum: 4.13 (1.16-14.73); interaction: p=0.97).

CONCLUSION

The association of revascularisation with the outcomes of patients with suspected coronary artery disease was not different between SPECT-first and CT-first strategies in a physician-referred fashion.

Diagnostic accuracy of an artificial neural network compared with statistical quantitation of myocardial perfusion images: a Japanese multicenter study

PURPOSE

Artificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable.

METHODS

The ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest 99mTc-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis.

RESULTS

The ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were >0.80.

CONCLUSION

The ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease.

NFκB2 Gene as a Novel Candidate that Epigenetically Responds to Interval Walking Training

Physical fitness has been reported to decrease the risk of lifestyle-related diseases. The present study evaluated genome-wide methylation under the hypothesis that interval walking training (IWT) imparted beneficial effects on health, particularly by epigenetically ameliorating susceptibility to inflammation. We screened DNA from peripheral blood samples via genome-wide microarray for genes whose methylation was affected by IWT, paying special attention to promoter regions, and identified over 40 hyper- or hypo-methylated genes following IWT that were not witnessed in controls. We next selected genes in which the degree of methylation change in the promoter region was correlated with energy consumption following IWT. In this way, we found the NFκB2 gene to have increased methylation in multiple regions of its promoter sequence following participation in an exercise regimen. Next, IWT-induced NFκB2 hyper-methylation was confirmed by a quantitative PyroSequencing assessment of methylation in samples obtained from independent subjects who also underwent IWT. The increase in NFκB2 gene promoter methylation by IWT indicates that this regimen may suppress pro-inflammatory cytokines. Thus, these results provide an additional line of evidence that IWT is advantageous in promoting health from an epigenetic perspective by ameliorating susceptibility to inflammation.

Diagnostic performance of a novel cadmium-zinc-telluride gamma camera system assessed using fractional flow reserve

BACKGROUND

Although the novel cadmium-zinc-telluride (CZT) camera system provides excellent image quality, its diagnostic value using thallium-201 as assessed on coronary angiography (CAG) and fractional flow reserve (FFR) has not been validated. METHODS AND RESULTS: To evaluate the diagnostic accuracy of the CZT ultrafast camera system (Discovery NM 530c), 95 patients underwent stress thallium-201 single-photon emission computed tomography (SPECT) and then CAG within 3 months. Image acquisition was performed in the supine and prone positions after stress for 5 and 3 min, respectively, and in the supine position at rest for 10 min. Significant stenosis was defined as ≥90% diameter narrowing on visual estimation, or a lesion with <90% and ≥50% stenosis and FFR ≤0.75. To detect individual coronary stenosis, the respective sensitivity, specificity, and accuracy were 90%, 64%, and 78% for left anterior descending coronary artery stenosis, 78%, 84%, and 81% for left circumflex stenosis, and 83%, 47%, and 60% for right coronary artery (RCA) stenosis. The combination of prone and supine imaging had a higher specificity for RCA disease than supine imaging alone (65% vs. 47%), with an improvement in accuracy from 60% to 72%.

CONCLUSIONS

Using thallium-201 with short acquisition time, combined with prone imaging, CZT SPECT had a high diagnostic yield in detecting significant coronary stenosis as assessed using FFR.

Usefulness of phase analysis to differentiate ischemic and non-ischemic etiologies of left ventricular systolic dysfunction in patients with heart failure

BACKGROUND

The detection of significant coronary artery disease (CAD) in patients with heart failure (HF) from left ventricular (LV) systolic dysfunction is crucial. We evaluated the usefulness of LV mechanical dyssynchrony as assessed by phase analysis compared with conventional gated single-photon emission computed tomography to identify ischemic etiology in patients with HF.

METHODS AND RESULTS

Forty-one consecutive patients who were initially admitted to hospital due to HF resulting from systolic dysfunction were evaluated. All patients underwent cardiac catheterization. LV mechanical dyssynchrony was evaluated using SyncTool™ to obtain the phase SD and histogram bandwidth. The changes in phase SD and histogram bandwidth with stress were calculated. The summed stress score, summed difference score, and changes in phase SD and histogram bandwidth with stress were greater in 26 patients with CAD than in 15 patients without CAD (P=0.001 and P=0.01). On multivariate analysis a phase SD of >14° (odds ratio [OR], 16.7) and a summed stress score of >17 (OR, 8.0) best differentiated LV dysfunction of ischemic and non-ischemic etiologies, with a sensitivity of 89% and a specificity of 87% (χ(2)=20), compared with summed stress score only (sensitivity, 46%; specificity, 87%; χ(2)=4.5).

CONCLUSIONS

The addition of phase analysis to conventional perfusion analysis enables better differentiation of the etiology of HF in patients with systolic dysfunction.

Postischemic myocardial stunning is superior to transient ischemic dilation for detecting multivessel coronary artery disease

BACKGROUND

Although poststress myocardial stunning is regarded as a marker for severe coronary artery disease (CAD), no study has yet compared the diagnostic value of poststress stunning with transient ischemic dilation (TID) of the left ventricle (LV) for detecting multivessel CAD.

METHODS AND RESULTS

A total of 271 patients with suspected or known CAD underwent adenosine triphosphate (ATP) loading and at-rest gated single-photon emission computed tomography. We assessed myocardial perfusion with a 20-segment model, and analyzed the changes in LV volumetric analysis induced by ATP and an automatically derived TID ratio. In 147 patients with multivessel CAD, the prevalence of multi-territorial ischemia was higher, and the post-ATP increase in end-systolic volume (ESV) and TID ratio were greater, than in the 124 with insignificant or single-vessel CAD (P<0.0001, for all cases). The receiver-operating characteristic curves analysis revealed cutoff values for ESV of 5 ml and a TID ratio of 1.11. Multivariate logistic regression analysis revealed that the combination of a poststress increase in ESV of ≥5 ml and multi-territorial ischemia best identified multivessel CAD, with a sensitivity of 78% and a specificity of 84%, whereas the TID ratio was not shown to be an independent predictor.

CONCLUSIONS

Post-ATP stress myocardial stunning is superior to the TID ratio for detecting multivessel CAD.

Importance of the ankle-brachial pressure index in the diagnosis of coronary artery disease in women with diabetes without anginal pain

BACKGROUND

Clinical symptoms of coronary artery disease (CAD) are often atypical in women, particularly in those with diabetes mellitus. Therefore, a simple diagnostic test to identify a high-risk subset of women with diabetes who are likely to have CAD is important.

METHODS AND RESULTS

A total of 407 consecutive patients (319 men and 88 women, age range 68 ± 11 years) with suspected CAD, who were not complaining of anginal pain, were evaluated. Among these patients, 170 had diabetes. Stress myocardial perfusion imaging and simultaneous brachial and ankle blood pressure measurements were performed to obtain the ischemic total perfusion deficit (TPD) and ankle-brachial pressure index (ABI), respectively. Ischemic TPD was not significantly different between men and women, whereas ischemic TPD was significantly greater in diabetic patients than in non-diabetic patients (6.9 ± 7.7% vs. 4.9 ± 6.1%; P = 0.005). In diabetic patients, ischemic TPD was not significantly different between men and women. However, women with ABI<0.9 showed significantly greater ischemic TPD than those with ABI≥0.9 (12.1 ± 10.8% vs. 5.1 ± 5.9%; P=0.04), whereas no difference in ABI was observed in men.

CONCLUSIONS

ABI was useful in evaluating CAD in asymptomatic women with diabetes to detect a high-risk subset showing the ischemic TPD of >10%, which is regarded as a scintigraphic indicator for coronary revascularization.

Prognostic value of post-ischemic stunning as assessed by gated myocardial perfusion single-photon emission computed tomography: a subanalysis of the J-ACCESS study

BACKGROUND

To determine the prognostic value of post-ischemic stunning, the Japanese assessment of cardiac event and survival study by quantitative gated myocardial single-photon emission computed tomography (SPECT) (J-ACCESS) study was reevaluated.

METHODS AND RESULTS

Of the 4,031 patients of the J-ACCESS, the present study evaluated 1,089 who completed gated SPECT both after stress and at rest. To assess post-ischemic stunning, the following measurements (left ventricular volumes after stress minus volumes at rest) were made: Deltaend-systolic volume (DeltaESV), Deltaenddiastolic volume (DeltaEDV) and Deltaejection fraction (DeltaEF). Myocardial stunning defined either as DeltaESV >or=5 ml, DeltaEDV >or=5 ml or DeltaEF <or=5% was observed in 21%, 22%, or 26%, respectively. During a 3-year follow-up, 101 cardiac events occurred. Kaplan-Meier survival estimation indicated worse event-free survival rates in patients with dilated ESV, dilated EDV, LVEF <or=45%, DeltaESV >or=5 ml or DeltaEDV >or=5 ml than in those without, whereas DeltaEF <or=5% did not predict events. Multivariate analysis demonstrated that LVEF <or=45% was the independent predictor for cardiac events. Nevertheless, DeltaEDV >or=5 ml was also an independent parameter, in addition to LVEF <or=45%, to predict the combined endpoint of cardiac death, myocardial infarction, and revascularization, but excluding heart failure.

CONCLUSIONS

These results indicate that post-ischemic stunning, as assessed by gated SPECT, is a marker for poor prognosis, particularly for ischemic cardiac events.

Clinical characteristics in patients showing ischemic electrocardiographic changes during adenosine triphosphate loading single-photon emission computed tomography

OBJECTIVES

Although ischemic electrocardiographic (ECG) changes during dipyridamole or adenosine infusion have been reported as a marker for severe coronary artery disease (CAD), few studies have focused on ST-segment changes with adenosine triphosphate (ATP)-loading myocardial single-photon emission computed tomography (SPECT).

METHODS AND SUBJECTS

Between January 2003 and August 2008, 4650 consecutive patients underwent ATP-loading SPECT. After 1412 patients with left bundle branch block, pacemaker rhythm, or previous coronary revascularization were excluded, 16 out of 3238 patients (0.5%) showed ischemic ST-segment depression during ATP-loading myocardial SPECT. They were aged 67+/-11 years; 10 were men and 6 women. Of these patients, 8 demonstrated perfusion abnormalities, whereas the remaining 8 showed normal myocardial perfusion imaging. In 6 of the 8 patients with abnormal SPECT, coronary angiography was performed, revealing left main trunk disease in 1 patient, 3-vessel disease in 4, 1-vessel disease with proximal left ascending artery occlusion in 1, and an insignificant lesion in 1. By contrast, no major cardiac event was observed in the 8 patients with normal SPECT during follow-up for an average of 2 years.

CONCLUSION

The prevalence of ischemic ST-segment changes during ATP loading is very rare. However, this finding should be taken into account since almost half of the patients, particularly those with perfusion abnormalities, may have severe CAD which requires coronary revascularization.

Comparative impact of scintigraphic parameters and B-type natriuretic peptide for the prediction of major cardiac events in the QGS-prognostic value in the elderly (Q-PROVE) study

BACKGROUND

Although B-type natriuretic peptide (BNP) has emerged as an important predictor for cardiac events, its effect on scintigraphic parameters is unknown.

METHODS AND RESULTS

The Q-PROVE study is a multicenter study to evaluate the prognostic value of ECG-gated SPECT in 175 Japanese elderly patients. In addition, BNP was assessed in 102 patients. Outcome assessment included cardiac events and noncardiac deaths. Twelve elderly patients (12%) had increased BNP >130 pg/ml. The summed stress score (SSS) was greater in patients with increased BNP than in those with normal BNP. Kaplan-Meier survival estimation indicated event-free survival rates at 3 years of 83%, 78%, 88%, 80%, respectively, in patients with BNP >130 pg/ml, SSS >or=7, summed difference score (SDS) >or=2, and dilated end-diastolic volume (EDV), but 98%, 98%, 100%, 94% in those with BNP <or=130 pg/ml, SSS <7, SDS <2 and normal EDV (P=0.006, P=0.005, P=0.0008, P=0.01). Multivariate analysis demonstrated that an SDS was the only independent predictor for subsequent cardiac events (hazard ratio =4.0, P=0.04).

CONCLUSIONS

Although BNP may have similar prognostic value to gated SPECT volumetric measurements in elderly patients with known or suspected coronary artery disease, myocardial ischemia as documented by SPECT is still indispensable for detecting high-risk patients compared with BNP alone.

Prevalence of coronary heart disease in patients with aortic aneurysm and/or peripheral artery disease

Although the presence of coronary heart disease (CHD) was the major determinant of perioperative mortality and long-term prognosis in patients with aortic aneurysm (AA) and peripheral artery disease (PAD), the prevalence and severity of CHD in patients with individual vascular diseases was unknown. Adenosine triphosphate-loading myocardial single-photon emission computed tomography therefore was performed in 788 patients with vascular diseases of the aorta and peripheral arteries, with AA in 500, PAD localized in the lower-limb arteries in 183, and combined AA and PAD in 105. Patients with known CHD, such as those with previous myocardial infarction or revascularization procedures, were excluded. Myocardial single-photon emission computed tomography was analyzed using a 20-segment model, and summed stress scores and summed difference scores were calculated. Stress-induced myocardial ischemia was defined as a summed difference score >or=2. The presence of myocardial ischemia was highest in patients with combined PAD and AA (73%), followed by PAD (55%; p = 0.005), and the lowest in patients with AA (37%; p <0.0001). Summed stress score was also the highest in patients with combined PAD and AA (11.6 +/- 9.9), followed by PAD (7.8 +/- 8.8; p <0.0001), and the lowest in patients with AA (4.0 +/- 6.2; p <0.0001 for both). Similarly, summed difference score was the highest in patients with combined PAD and AA (6.4 +/- 6.1), followed by PAD (4.4 +/- 5.7; p = 0.001) and AA (2.3 +/- 4.0; p <0.0001 for both). In conclusion, the prevalence of CHD in patients with PAD was >50%, and although myocardial ischemia was observed in only (1/3) of patients with AA, its prevalence not only doubled, but also indicated extensive myocardial ischemia when combined with PAD. Thus, cardiac evaluation was particularly important in patients with combined AA and PAD.

Diagnostic value of left ventricular function after adenosine triphosphate loading and at rest in the detection of multi-vessel coronary artery disease using myocardial perfusion imaging

BACKGROUND

Although transient left ventricular (LV) dilation is a well-known marker for extensive coronary artery disease (CAD), few studies performed quantitative analysis of LV function of post adenosine triphosphate (ATP) stress and at rest to detect extensive CAD.

METHODS

One hundred nineteen patients with suspected CAD underwent post-stress and resting gated single-photon emission computed tomography (SPECT). Myocardial perfusion was assessed with a 20-segment model, and the changes in LV volume and function with ATP were analyzed. In addition, the stress-induced volume ratio (SIVR), defined as stress-to-rest ratios (end-systolic volume x 5 + end-diastolic volume), was calculated. All the patients underwent coronary angiography within 3 months of gated SPECT.

RESULTS

In the 62 patients with multi-vessel CAD, the summed stress score (SSS) (16.6 +/- 8.7 vs 11.5 +/- 9.1; P < .002), summed difference score (SDS) (9.6 +/- 5.8 vs 3.9 +/- 4.2; P < .0001), the post-stress increase in end-diastolic volume (EDV) (7.7 +/- 7.9 vs 2.2 +/- 5.3 mL; P < .0001), the post-stress increase in end-systolic volume (ESV) (9.4 +/- 6.0 vs 2.7 +/- 4.0 mL; P < .0001), and the (SIVR) (1.21 +/- 0.14 vs 1.06 +/- 0.10; P < .0001) were greater than in the 57 patients with insignificant or single-vessel CAD, whereas the post-stress increase in ejection fraction (EF) was less (-6.0 +/- 4.9 vs -2.0 +/- 4.4%; P < .0001). In the detection of multi-vessel CAD, an SSS of > or = 14 and an SDS of > or = 9 showed sensitivities of 57% and 52%, respectively, and specificities of 63% and 88%, respectively, while increase in EDV of > or = 6 mL, increase in ESV of > or = 6 mL, decrease in EF of > or = 5% after stress, and SIVR of > or = 1.13 demonstrated sensitivities of 60%, 81%, 60%, and 74% and specificities of 74%, 77%, 77%, and 79%, respectively. The multivariate discriminant analysis revealed that the combination of post-stress increase in ESV and the SDS best identified multi-vessel CAD, with 81% sensitivity and 77% specificity (chi(2) = 63.6), whereas the SDS alone showed 52% sensitivity and 88% specificity (chi(2) = 22.4).

CONCLUSIONS

The addition of "post-ATP stress" and "at rest" LV functional analysis using gated SPECT to conventional perfusion analysis helps to better identify patients with multi-vessel CAD.

Important parameters in the detection of left main trunk disease using stress myocardial perfusion imaging

OBJECTIVES

We sought noninvasively to diagnose left main trunk (LMT) disease using myocardial perfusion imaging (MPI).

METHODS

Five hundred and eight patients with suspected coronary artery disease (CAD) underwent both stress MPI and coronary angiography. The extent and severity of perfusion abnormalities were assessed using a 20-segment model. In addition, perfusion defects in both left anterior descending and left circumflex arterial territories were defined as a left main (LM) pattern defect, and those in 3-coronary arterial territories as a 3-vessel pattern defect.

RESULTS

In 42 patients with LMT disease, a summed stress score (19.4 ± 10.0 vs. 13.5 ± 10.0; p < 0.0001) and a summed rest score (12.1 ± 9.7 vs. 7.0 ± 7.8; p = 0.002) were greater than in 466 patients without LMT disease, while a summed difference score was similar (7.3 ± 7.7 vs. 6.5 ± 6.1; p = NS). The prevalence of an LM-pattern defect was low in both groups (12% vs. 8%; p = NS). However, a 3-vessel pattern defect (33% vs. 7%; p < 0.0001), lung uptake of radiotracers (38% vs. 11%; p < 0.0001), and transient ischemic dilation (31% vs. 13%; p = 0.003) were more frequently observed in patients with LMT disease than in those without. Logistic regression analysis showed that a 3-vessel pattern defect (OR=3.5, 95% CI = 1.4-8.8; p = 0.007), lung uptake of radiotracers (OR = 2.5, 95% CI = 1.1-5.7; p = 0.03), and previous myocardial infarction (MI) (OR = 2.4, 95% CI = 1.0-5.7; p = 0.05) were the most important parameters to detect LMT disease. After excluding 163 patients with previous MI, a repeat analysis revealed that lung uptake of radiotracers (OR = 8.2, 95% CI = 2.3-29.2; p = 0.001) and an LM-pattern defect (OR = 6.3, 95% CI = 1.4-27.2; p < 0.02) were independent predictors for LMT disease.

CONCLUSION

In the identification of LMT disease, lung uptake of radiotracers was a single best parameter, which was independent of the presence or absence of previous MI.

Differential effects comparing exercise and pharmacologic stress on left ventricular function using gated Tc-99m sestamibi SPECT

OBJECTIVE

Although post-ischemic stunning has emerged as an important marker for severe coronary artery disease (CAD), differences in stress methods may have different effects on left ventricular (LV) volumes and function.

METHODS

To assess differential effects comparing exercise and pharmacologic stress on the LV measurements, (99m)Tc-sestamibi gated single-photon emission computed tomography (SPECT) acquired more than 30 min after stress and at rest was evaluated in 38 patients undergoing adenosine triphosphate (ATP) stress (ATP group) and 38 age-and sex-matched patients subjected to exercise stress (Ex group) among 268 patients with normal SPECT findings.

RESULTS

Coronary risk factors and LV volumetric measurements at baseline were similar in the two groups. Compared with volumetric measurements at rest, end-diastolic volume (EDV) increased (72 +/- 21 ml to 74 +/- 21 ml; P = 0.01), end-systolic volume increased (25 +/- 12 ml to 28 +/- 13 ml; P = 0.001), and ejection fraction (EF) decreased after stress (66% +/- 8% to 63% +/- 9%; P < 0.002) in the ATP group. In the Ex group, by contrast, no such change was observed. In addition, changes in EDV (3 +/- 6 vs. -1 +/- 5 ml; P = 0.01) and the stress-to-rest ratio of EDV (1.04 +/- 0.09 vs. 0.99 +/- 0.08; P < 0.02) after stress were greater in the ATP than in the Ex group.

CONCLUSIONS

Differential effects of stress methods on LV volumes persist more than 30 min after the stress. These findings should be kept in mind when interpreting post-ischemic stunning.

Clinical significance of inter-arm pressure difference and ankle-brachial pressure index in patients with suspected coronary artery disease

BACKGROUND

Although measuring blood pressure at the bilateral brachia is common in medical practice, its clinical significance in patients with suspected coronary artery disease (CAD) has not been fully clarified.

METHODS

To define the significance of inter-arm systolic blood pressure difference in patients with suspected CAD, and to assess the relationship between inter-arm pressure difference and CAD, simultaneous brachial and ankle blood pressure measurements and stress myocardial single-photon emission computed tomography (SPECT) were performed in 386 consecutive patients with suspected CAD, excluding those with previous myocardial infarction or coronary revascularization.

RESULTS

Subclavian artery stenosis, defined as > or = 15 mmHg inter-arm systolic blood pressure difference, was found in 27 patients (7%). Age (65 +/- 12 vs 65 +/- 11 years), male sex (21/27 vs 244/359), prevalence of hypertension(63% vs 56%), hypercholesterolemia (63% vs 62%), diabetes mellitus(33% vs 38%), cigarette smoking (44% vs 41%) and family history of CAD (15% vs 12%) were similar between patients with subclavian artery stenosis and those without. The incidence of decreased ankle-brachial pressure index (ABI) was higher (37% vs 12%, p = 0.001), and percentage ischemic myocardium as assessed by SPECT was greater (9.0 +/- 8.5% vs 5.6 +/- 6.6%, p < 0.05) in patients with subclavian artery stenosis than in those without. Furthermore, significant correlations were observed between inter-arm pressure difference and percentage ischemic myocardium (r = 0.13; p = 0.01), and ABI (r = -0.26, p < 0.0001). Among 386 patients, 283 underwent coronary angiography, and 63% of those who had inter-arm blood pressure difference had CAD. Furthermore, 83% of those CAD patients had multi-vessel CAD, which is regarded as a high-risk subset for subsequent cardiac events.

CONCLUSIONS

Inter-arm pressure difference is often found in patients with suspected CAD, and is associated with significant CAD and peripheral artery disease. Thus, inter-arm pressure difference may be regarded as a simple marker for coronary and peripheral artery diseases.

Diagnostic value of left ventricular function after stress and at rest in the detection of multivessel coronary artery disease as assessed by electrocardiogram-gated SPECT

BACKGROUND

Although transient left ventricular (LV) dilation is a well-known marker for extensive coronary artery disease (CAD), few studies have performed quantitative analysis of LV function after stress and at rest to detect extensive CAD.

METHODS AND RESULTS

Poststress and resting gated single photon emission computed tomography (SPECT) was performed in 175 patients with suspected CAD. All of the patients underwent coronary angiography within 3 months of gated SPECT. In the 83 patients with multivessel CAD, the summed difference score was greater (9.2 +/- 7.0 vs 3.3 +/- 4.0, P < .0001), the poststress increase in end-systolic volume (ESV) was larger (7.0 +/- 8.0 mL vs -0.8 +/- 4.7 mL, P < .0001), and the poststress increase in ejection fraction (EF) was less (-4.7% +/- 5.4% vs -0.4% +/- 4.5%, P < .0001) than in the 92 patients with insignificant or single-vessel CAD. In the detection of multivessel CAD, a summed difference score of 9 or greater showed a sensitivity of 46% and specificity of 90%, whereas an increase in ESV of 5 mL or greater and a decrease in EF of 5% or greater after exercise had a sensitivity of 66% and 52%, respectively, and specificity of 87% and 83%, respectively. The multivariate discriminant analysis revealed that the combination of poststress increase in ESV, summed difference score, and diabetes mellitus best identified multivessel CAD, with a sensitivity of 72% and specificity of 84% (chi(2), 81.7).

CONCLUSIONS

The addition of poststress and at-rest LV functional analysis by use of gated SPECT to conventional perfusion analysis helps to better identify patients with multivessel CAD.

The role of 123I-metaiodobenzylguanidine myocardial scintigraphy in the diagnosis of Lewy body disease in patients with dementia in a memory clinic

Reduction in cardiac (123)I-metaiodobenzylguanidine (MIBG) uptake is a characteristic feature of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), and is useful in distinguishing them from other neurodegenerative disorders. The aim of this study was to investigate the role of this method of scintigraphy in the differential diagnosis of dementia in our Memory Clinic. We performed MIBG scintigraphy in patients with dementia referred to the Memory Clinic and compared the heart-to-mediastinum (H/M) ratio of MIBG uptake. Thirty out of 32 patients with DLB and all 9 PD with dementia patients had reduced H/M ratios, whereas 37 out of 40 patients with Alzheimer's disease had normal H/M ratios. Most patients with vascular dementia, frontotemporal dementia, and other dementias had normal H/M ratios. The overall sensitivity to positively identify patients with Lewy body disease (including DLB and PD with dementia) was 95%, and the specificity to distinguish them from patients with other types of dementias was 87%. MIBG scintigraphy showed a high sensitivity for the detection of Lewy body disease, and also a high specificity for discrimination from other types of dementia. The scintigraphy may provide a valuable and adjunctive method in the diagnosis of Lewy body disease and a differential diagnostic tool for patients with dementias.

Quantitative Gated Single-Photon Emission Computed Tomography With 99mTc Sestamibi Predicts Major Cardiac Events in Elderly Patients With Known or Suspected Coronary Artery Disease The QGS-Prognostic Value in the Elderly (Q-PROVE) Study

BACKGROUND

Although electrocardiogram-gated single-photon emission computed tomography (SPECT) may be useful in risk stratification of elderly patients with coronary artery disease (CAD), few studies have prospectively evaluated its prognostic value in this patient population.

METHODS AND RESULTS

A total of 175 patients aged 75 years or more with known or suspected CAD were prospectively evaluated by stress gated SPECT using a 20-segment model and an automatic functional analysis. Patients with acute coronary syndrome within the previous 3 months, and those who underwent coronary revascularization within 3 months after the SPECT study were excluded. Outcome assessment included prespecified cardiac events and noncardiac deaths. During a mean follow-up of 3.4 years, there were 18 cardiac events: 2 cardiac deaths, 1 nonfatal myocardial infarction, 3 coronary artery bypass grafting, 5 percutaneous coronary interventions, 1 unstable angina, 4 heart failures, and 2 malignant arrhythmias. Kaplan-Meier survival estimation indicated an event-free survival rate of 98.1% at 3 years in patients without myocardial ischemia, but 79.9% in those with ischemia as documented by gated SPECT (p=0.0001). Multivariate analysis using the Cox proportional hazard model demonstrated that stress-induced myocardial ischemia was the only independent predictor for subsequent cardiac events (p<0.01).

CONCLUSIONS

Stress gated SPECT predicts cardiac events in patients aged 75 years or more with known or suspected CAD and may have a role in risk stratification of this patient population.

Diagnostic significance of positive I-123 BMIPP despite negative stress Tl-201 myocardial imaging in patients with suspected coronary artery disease

BACKGROUND

There is frequently discordance in the interpretation of myocardial single-photon emission computed tomography images using both rest iodine-123 15-(p-iodophenyl)-3-(R,S) methylpentadecanoic acid (BMIPP) and stress thallium-201 ((201)Tl); that is, negative BMIPP vs positive (201)Tl studies. However, little attention has been paid to reverse discordance (ie, positive BMIPP despite negative stress (201)Tl).

METHODS AND RESULTS

In the present study 105 consecutive patients with suspected coronary artery disease (CAD) who underwent both rest BMIPP and stress (201)Tl imaging were evaluated. No patient with previous myocardial infarction was included. Scintigraphic studies revealed that BMIPP was in concordance with (201)Tl in 71 patients: both were positive in 38 and negative in 33, whereas both were discordant in 20 and reverse discordant in 14. In patients with reverse discordance, the pattern of BMIPP abnormality was segmental in 8 and spotty in 6; the former was related to coronary territory. Based on the BMIPP findings and clinical symptoms, 7 patients with positive BMIPP despite negative (201)Tl underwent coronary angiography: 3-vessel CAD was found in 3 patients, 2-vessel CAD in 1, coronary spasm in 2, and insignificant lesions in 1. In the remaining 7 patients, no cardiac event was observed during 2-year follow-up.

CONCLUSIONS

In patients showing positive BMIPP despite negative (201)Tl, a segmental BMIPP perfusion abnormality indicates a high likelihood for CAD, despite normal stress (201)Tl imaging. Thus, adding BMIPP to (201)Tl imaging may help to better identify patients with significant CAD, including multivessel disease.

Comparison of post-exercise and post-vasodilator stress myocardial stunning as assessed by electrocardiogram-gated single-photon emission computed tomography

BACKGROUND

Exercise gated single-photon emission computed tomography (SPECT) using technetium-99m (99mTc)-sestamibi evaluates both myocardial perfusion during stress and wall motion >30 min after the stress, which has the potential to assess not only exercise-induced myocardial ischemia but also the development of myocardial stunning.

METHODS AND RESULTS

To evaluate the incidence of post-stress myocardial stunning, as well as comparing the effects of different stress methods on the development of stunning, 179 consecutive patients with known or suspected coronary artery disease (CAD) underwent (99m)Tc-sestamibi SPECT with either exercise (n=135) or adenosine triphosphate disodium (ATP) (n=44). Electrocardiogram-gated SPECT images were acquired >30 min after the stress and again 4 h later, and perfusion and wall motion were evaluated. Post-stress myocardial stunning occurred in 24 patients (13%): 22 after exercise and 2 after ATP stress. The magnitude of the transient wall motion abnormality after exercise was greater in patients with severe ischemia, compared with those with mild-to-moderate ischemia (p<0.0001). By contrast, with ATP stress, the magnitude of the transient wall motion abnormality was similar, regardless of the severity of perfusion abnormality. Furthermore, a significant correlation between summed difference score and transient wall motion abnormality was found after exercise (r=0.68, p<0.0001). With ATP, however, no such correlation was observed (r=0.28, p=NS).

CONCLUSIONS

Using 99mTc-sestamibi gated SPECT, myocardial stunning is frequently observed after exercise and correlates with the severity of myocardial ischemia, but this does not occur with ATP, which is regarded as a specific marker for severe CAD.