Yuko Igarashi

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.

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

ObjectiveAlthough 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.MethodsTo assess differential effects comparing exercise and pharmacologic stress on the LV measurements, 99mTc-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.ResultsCoronary risk factors and LV volumetric measurements at baseline were similar in the two groups. Compared with volumetric measurements at rest, enddiastolic 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.ConclusionsDifferential 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 value of vasodilator-induced left ventricular dyssynchrony as assessed by phase analysis to detect multivessel coronary artery disease

Purpose: Phase analysis was recently developed to allow left ventricular(LV)mechanical dyssynchrony to be assessed by gated single-photon emission computed tomography(SPECT) . However, few studies have analyzed LV dyssynchrony during pharmacological stress and at rest by applying phase analysis to detect multivessel coronary artery disease(CAD)using the SyncTool TM . Methods: Adenosine triphosphate(ATP)loading electrocardiogram-gated 99m Tc-sestamibi SPECT was performed on 180 patients with suspected or known CAD. LV dyssynchrony was evaluated using the SyncTool TM ; the phase standard deviation(SD)and histogram bandwidth were derived. Results: The summed stress score(SSS) , summed difference score(SDS) , post-stress increase in phase SD, and histogram bandwidth were greater in 78 patients with multivessel CAD than in 102 patients with insignificant or single-vessel CAD. In the detection of multivessel CAD, SSS of >9 and SDS of >5 showed sensitivities of 74% and 74%,and specificities of 71% and 78% respectively, whereas an increase in phase SD>8.3°and in histogram bandwidth >16°after ATP loading had sensitivities of 62% and 74% and specificities of 77% and 68%, respectively. A multivariate logistic analysis revealed that the identification of multivessel CAD was superior with the combination of a post-ATP increase in phase SD, increase in histogram bandwidth, and SDS(sensitivity 82%, specificity 76%, chi-square=80.0)than with SDS alone (sensitivity 74%, specificity 78%, chi-square=58.9) . Conclusion: The addition of ATP-induced LV dyssynchrony parameters to conventional perfusion analysis enabled the superior identification of patients with multivessel CAD.

A flow-limiting stenosis is the major determinant of exercise-induced myocardial stunning in patients with coronary artery disease

BACKGROUND Although stress-induced myocardial stunning often develops after exercise testing, determinants of this phenomenon have not been evaluated. METHODS AND RESULTS Thirty-one patients with 1-vessel coronary artery disease, limited to the left anterior descending artery (LAD), were evaluated by quantitative coronary angiography (QCA) and intracoronary pressure measurements to calculate fractional flow reserve (FFR). In addition, electrocardiogram-gated technetium-99m sestamibi myocardial imaging was acquired >30 min after exercise and 4 h later to assess the development of stunning. Exercise-induced myocardial stunning was observed in 11 patients (35%). In patients with myocardial stunning, a summed stress score (17.3+/-7.1 vs. 8.1+/-6.2, p<0.001), summed difference score (10.3+/-4.1 vs. 2.7+/-1.9, p<0.0001), and wall motion difference score (4.8+/-2.8 vs. 0.9+/-1.1, p<0.0001) were greater than in those without, while diameter stenosis calculated by QCA (55.1+/-17.3% vs. 29.8+/-17.3%, p<0.0001) was greater and FFR reduced significantly (0.54+/-0.13 vs. 0.83+/-0.06, p<0.0001). Of note, 4 out of 21 patients (19%) with <50% LAD stenosis developed myocardial stunning, whereas only one patient with FFR of 0.64 or greater showed stunning. The best cut-off value was determined as 0.64 for FFR and 46% for QCA, providing 91% sensitivity and 100% specificity for FFR (chi-square=57.2), but 91% sensitivity and 80% specificity for diameter stenoses measured by QCA (chi-square=17.8). CONCLUSIONS The major determinant for exercise-induced myocardial stunning was a severe flow-limiting coronary stenosis, which was more important than anatomical evaluation based on luminal narrowing alone.

Diagnostic Performance of a Cadmium-Zinc-Telluride Single-Photon Emission Computed Tomography System With Low-Dose Technetium-99m as Assessed by Fractional Flow Reserve

BACKGROUND Although stress single-photon emission computed tomography (SPECT) using a cadmium-zinc-telluride (CZT) camera facilitates radiation dose reduction, only a few studies have evaluated its diagnostic accuracy in Japanese patients by applying fractional flow reserve (FFR) measurements. METHODSANDRESULTS We prospectively evaluated 102 consecutive patients with suspected or known coronary artery disease with a low-dose stress/rest protocol ((99m)Tc radiotracer 185/370 MBq) using CZT SPECT. Within 3 months, coronary angiography was performed and a significant stenosis was defined as ≥90% diameter narrowing on visual estimation, or as a lesion of <90% and ≥ 50% stenosis with FFR ≤0.80. To detect individual coronary stenosis, the respective sensitivity, specificity, and accuracy were 86%, 75%, and 82% for left anterior descending artery stenosis, 76%, 81%, and 79% for left circumflex artery stenosis, and 87%, 92%, and 90% for right coronary artery stenosis. When limited to 92 intermediate stenotic lesions in which FFR was measured, stress SPECT showed 77% sensitivity, 91% specificity, and 84% accuracy, whereas the diagnostic value decreased to 52% sensitivity, 68% specificity, and 58% accuracy based only on visual estimation of ≥75% diameter narrowing. CONCLUSIONS CZT SPECT demonstrated a good diagnostic yield in detecting hemodynamically significant coronary stenoses as assessed by FFR, even when using a low-dose (99m)Tc protocol with an effective dose ≤5 mSv. (Circ J 2016; 80: 1217-1224).

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.

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.

Application of pressure-derived myocardial fractional flow reserve in chronic hemodialysis patients

BACKGROUND Although fractional flow reserve (FFR) measurements during coronary angiography are performed in routine clinical practice, few studies have evaluated FFR measurements in dialysis patients. METHODS We retrospectively studied 42 hemodialysis patients with suspected or known coronary artery disease (CAD) who underwent stress myocardial perfusion imaging and coronary angiography with FFR measurements for 61 coronary lesions. The cut-off value for FFR to detect myocardial ischemia was determined by receiver operating characteristic (ROC) curve analysis. RESULTS There were 61 coronary vessels measured by FFR. The FFR range was 0.34-0.93 with a mean of 0.74±0.13. The ROC curve analysis revealed that the best cut-off value of FFR for detecting myocardial ischemia was 0.76 (p<0.0001), with 70% sensitivity, 86% specificity, and 76% accuracy for myocardial ischemia. Compared with patients who had positive myocardial ischemia and an FFR≤0.76, those who had negative myocardial ischemia despite an FFR≤0.76 had less left ventricular (LV) mass index, whereas patients who had positive myocardial ischemia despite an FFR>0.76 had greater LV mass indexor serum calcium-phosphorus product. CONCLUSIONS The cut-off value of FFR for myocardial ischemia in chronic hemodialysis patients is similar to that in other CAD patients. However, caution is necessary when FFR measurements are applied to dialysis patients with significantly increased LV mass index or serum calcium-phosphorus product.

DIAGNOSTIC VALUE OF VASODILATOR-INDUCED LEFT VENTRICULAR DYSSYNCHRONY IN THE DETECTION OF MULTI-VESSEL CORONARY ARTERY DISEASE USING MYOCARDIAL PERFUSION IMAGING

Recently, the phase analysis has been developed to allow assessment of LV mechanical dyssynchrony by electrocardiogram-gated SPECT. However, few studies were performed to analyze LV dyssynchrony during pharmacologic stress and at rest, applying the phase analysis using the SyncToolTM to detect multi