Relationship of SYNTAX score to myocardial ischemia as assessed on myocardial perfusion imaging.

BACKGROUND: Although the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is used to characterize coronary anatomy based on 9 anatomic criteria such as lesion location and complexity, the relationship between SYNTAX score and myocardial ischemia has yet to be elucidated. METHODS AND RESULTS: A total of 158 consecutive patients with suspected or known coronary artery disease (CAD), who underwent both (99m)Tc-sestamibi single-photon emission computed tomography (SPECT) and coronary angiography, were evaluated. Stress SPECT was assessed using a 17-segment model, and the percentage of the myocardial defect scores (DS) was calculated. In 37 patients with intermediate-high SYNTAX scores (>22), the number of men and the prevalence of multi-vessel CAD were significantly higher, and the % stress and ischemic DS were significantly greater than in 121 patients with low SYNTAX scores (≤22). Coronary risk factors, however, were similar between the 2 groups. The % stress and ischemic DS significantly correlated with SYNTAX score. In patients with a low SYNTAX score, % stress and ischemic DS also significantly correlated with the SYNTAX score, whereas no such correlation was observed in the intermediate-high SYNTAX score group. CONCLUSIONS: SYNTAX score correlated well with myocardial ischemia as assessed on stress SPECT in general. The higher the SYNTAX score, however, the less clear was the correlation with the extent of myocardial ischemia.

Diagnostic value of left ventricular dyssynchrony after exercise and at rest in the detection of multivessel coronary artery disease on single-photon emission computed tomography.

BACKGROUND: Although stress-induced left ventricular (LV) wall motion abnormality is a well-known marker for extensive coronary artery disease (CAD), no study has yet analyzed whether phase analysis of exercise-induced LV mechanical dyssynchrony may have enhanced diagnostic value over conventional perfusion analysis in the detection of multivessel CAD. METHODS AND RESULTS: A total of 278 patients with suspected or confirmed CAD underwent both exercise stress (99m)Tc-sestamibi gated single-photon emission computed tomography and coronary angiography. LV mechanical dyssynchrony was evaluated using the SyncTool to obtain the phase SD and histogram bandwidth. In the detection of 128 patients with multivessel CAD, a summed stress score (SSS) of ≥9 showed a sensitivity of 84% and a specificity of 53%, while an increase in phase SD of ≥4.4° and a bandwidth of ≥14° after exercise had sensitivities of 74% and 68%, and specificities of 84% and 91%, respectively. On multivariate analysis the combination of post-stress increases in phase SD, histogram bandwidth, transient ischemic dilation (TID) ratio and SSS best identified multivessel CAD (sensitivity 77%, specificity 88%, χ(2)=181.8), compared with TID ratio and SSS only (sensitivity 70%, specificity 76%, χ(2)=68.9). CONCLUSIONS: The addition of phase analysis to evaluate exercise-induced LV mechanical dyssynchrony on conventional perfusion analysis enabled better identification of patients with multivessel CAD.

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.

Sex-specific approach to gated SPECT volumetric analysis after stress and at rest to detect high-risk coronary artery disease.

OBJECTIVES: To determine the role of quantitative analysis of poststress and resting left ventricular function using sex-specific criteria to detect high-risk coronary artery disease (CAD) as defined by the Duke CAD Prognostic Index. METHODS AND RESULTS: Stress technetium-99m-sestamibi-gated single-photon emission computed tomography and coronary angiography were performed in 407 consecutive patients (300 men, 107 women) with suspected CAD. The cut-off point for high-risk CAD was defined as a Duke CAD Prognostic Index of 42. The stress-to-rest ratios of end-diastolic volume (rEDV) and end-systolic volume (rESV) were analyzed. In 102 patients with high-risk CAD, the summed difference scores, rEDV and rESV, were greater than in 305 patients with low-risk to intermediate-risk CAD. The receiver operating characteristic curves revealed that the optimal cut-off points for rEDV and rESV to detect high-risk CAD were 1.10 and 1.11, respectively. Sex-specific rEDV was 1.08 in men, 1.11 in women, and sex-specific rESV was 1.09 in men and 1.20 in women. Multivariate discriminant analysis showed that the combination of sex-specific rEDV, sex-specific rESV, and summed difference scores greater than or equal to 8 best identified high-risk CAD, with a sensitivity of 75% and specificity of 76%. CONCLUSION: The addition of a sex-specific approach to left ventricular functional analysis using gated single-photon emission computed tomography on conventional perfusion analysis, may help better identify patients with high-risk CAD as defined by the Duke CAD Prognostic Index.

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

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.

The diagnostic utility of the Heston index in gated SPECT to detect multi-vessel coronary artery disease.

OBJECTIVES: Although the Heston index, derived left ventricular (LV) volumetric analysis, is reported to best represent transient LV dilation on non-gated single-photon emission computed tomography (SPECT), its diagnostic performance has not been proven to identify extensive coronary artery disease (CAD) as assessed by coronary angiogram. Accordingly, we sought to evaluate the diagnostic utility of Heston index to detect multi-vessel CAD. METHODS: Post-stress and resting electrocardiogram-gated 99mTc-sestamibi SPECT was performed in 223 patients with suspected or known CAD. All of the patients underwent coronary angiography within 3 months of gated SPECT. The summed stress, summed rest, and summed difference scores were calculated using a 20-segment model. The left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were calculated automatically with the QGS program. In addition, stress-to-rest ratios of EDV, ESV, and (ESVx5+EDV) were calculated; the latter was defined as Heston index. RESULTS: In the 104 patients with multi-vessel CAD, the summed stress score (17.5+/-10.0 vs. 11.7+/-9.2, p<0.001), the summed difference score (9.1+/-6.3 vs. 4.3+/-4.2, p<0.0001), the Heston index (1.17+/-0.15 vs. 1.02+/-0.13, p<0.0001), the stress-to-rest ratio of EDV (1.05+/-0.10 vs. 0.99+/-0.09; p<0.0001), and that of ESV (1.23+/-0.21 vs. 1.04+/-0.17; p<0.0001, respectively) were greater than in the 119 patients with one-vessel CAD or insignificant lesion. The best cut-off value was determined as 1.09 for Heston index, giving a sensitivity of 76%, specificity of 77% for detection of multi-vessel CAD. Multiple stepwise logistic regression analysis showed that Heston index >or =1.09, summed stress score > or =14, and summed difference score > or =9 were the independent predictors of detecting multi-vessel CAD, yielding a sensitivity of 76% and specificity of 77% (global chi 2, 88.8). CONCLUSIONS: The Heston index is simple and achieves higher diagnostic value in the detection of multi-vessel CAD, compared with conventional analysis alone.

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.

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.

Correlation between myocardial uptake of technetium-99m-sestamibi and pressure-derived myocardial fractional flow reserve.

OBJECTIVES: Development of the coronary pressure wire has facilitated the measurement of fractional flow reserve (FFR) to assess the functional severity of coronary artery stenoses. METHODS: This study evaluated the correlations between FFR and myocardial direct counts of technetium-99m(99mTc)-sestamibi in 20 patients (16 men, 4 women, mean age 66 +/- 8 years) who underwent 99mTc-sestamibi single-photon emission computed tomography (SPECT) with the 2-day protocol using 740 MBq of 99mTc-sestamibi each day. Visual assessment of myocardial imaging and quantitative analysis with the measurement of percent uptake and direct count of 99mTc-sestamibi were performed. RESULTS: Visual assessment of myocardial imaging revealed that reversibility of 99mTc-sestamibi perfusion defects was correlated with FFR of < 0.75, which is regarded as functionally important stenosis (17/20 vs 3/20, kappa = 0.71, p < 0.002). Regional reversibility score did not correlate with FFR (r = -0.40, p = NS). Quantitative analysis revealed that the change in 99mTc-sestamibi percent uptake with pharmacologic stress using adenosine triphosphate disodium (ATP) also did not correlate with FFR (r = 0.35, p = NS). In contrast, percent increase in 99mTc direct counts with ATP was lower in patients with FFR of < 0.75 than in those with FFR of > = 0.75 (-4 +/- 16% vs 24 +/- 30%, p < 0.01). In addition, a significant correlation (r = 0.70, p < 0.001) was observed between percent increase in 99mTc direct counts with ATP and FFR. CONCLUSIONS: These results suggest that quantitative analysis of 99mTc-sestamibi scintigraphy enables the assessment of the magnitude of functional significance of coronary stenosis.

Correlation between thallium-201 myocardial perfusion defects and the functional severity of coronary artery stenosis as assessed by pressure-derived myocardial fractional flow reserve.

Although a relationship between the coronary pressure-derived fractional flow reserve (FFR) and the presence of myocardial ischemia as demonstrated by radionuclide imaging has been reported in a select group of patients, it remains to be established whether this relation also holds true in actual clinical settings with a heterogeneous group of patients. Accordingly, 194 coronary vessels and their supply territories were evaluated in 165 consecutive patients with suspected or known coronary artery disease. An FFR <0.75, which is regarded as indicative of functionally important stenosis, showed a significant correlation with the redistribution of (201)Tl (p<0.0001), with a sensitivity of 79% and specificity of 73%. In 70 infarct-related coronary arteries, the sensitivity and specificity were 79% and 75%, respectively, whereas in the 124 remaining vessels that were not related to the myocardial infarct, the sensitivity and specificity were 80% and 72%, respectively. In addition, the FFR exhibited a significant inverse correlation with the (201)Tl reversibility score (r=-0.62; p<0.0001). These results suggest that the FFR has a significant relationship with scintigraphic evidence of myocardial ischemia and can be regarded as a marker of its presence or absence in patients in actual clinical settings.

High-tension electrical injury to the heart as assessed by radionuclide imaging.

To evaluate cardiac complications associated with electrical injury, 7 patients with high-tension electrical injury (6,600 V alternating current) underwent 201Tl and 123I-metaiodobenzylguanidine (MIBG) imaging in addition to conventional electrocardiographic and echocardiographic assessments. Electrocardiography showed transient atrial fibrillation, second degree atrioventricular block, ST-segment depression, and sinus bradycardia in each patient. Echocardiography showed mild hypokinesis of the anterior wall in only 2 patients, but 201Tl and 123I-MIBG myocardial scintigraphy showed an abnormal scan image in 6/7 and 5/6 patients, respectively. Decreased radionuclide accumulation was seen primarily in areas extending from the anterior wall to the septum. Decreased radionuclide accumulation was smaller in extent and milder in degree in 123I. MIBG than in 201Tl imaging. These results suggest that even in patients without definite evidence of severe cardiac complications in conventional examinations, radionuclide imaging detects significant damage due to high-tension electrical injury, in which sympathetic nerve dysfunction might be milder than myocardial cell damage.