Incremental value of regional wall motion analysis immediately after exercise for the detection of single-vessel coronary artery disease: study by separate acquisition, dual-isotope ECG-gated single-photon emission computed tomography

Stress Myocardial Perfusion Imaging Interpretation From the Viewpoint of Fractional Flow Reserve

BACKGROUND

Myocardial perfusion imaging (MPI) and fractional flow reserve (FFR) are established approaches to the assessment of myocardial ischemia. Recently, various FFR cutoff values were proposed, but the diagnostic accuracy of MPI in identifying positive FFR using various cutoff values is not well established.

METHODS AND RESULTS

We retrospectively studied 273 patients who underwent stress MPI and FFR within a 3-month period. Results for FFR were obtained from 218 left anterior descending artery (LAD) lesions and 207 non-LAD lesions. Stress MPI and FFR demonstrated a good correlation in the detection of myocardial ischemia. However, the positive predictive value (PPV) of FFR for detecting MPI-positive lesions at the optimal FFR thresholds was insufficient (44% for LAD and 65% for non-LAD lesions). This was caused by a sharp drop in PPV at an FFR threshold of 0.7 or more. Notably, 41% of the lesions with normal MPI demonstrated FFRs <0.80. However, MPI-negative lesions had an extremely low lesion rate with FFR <0.65 (6%). Conversely, 78% and 41% of MPI-positive lesions had FFR <0.80 and <0.65, respectively.

CONCLUSIONS

The data confirmed that decisions based on MPI are reasonable because MPI-negative patients have an extremely low rate of lesions with a FFR below the cutoff point for a hard event, and MPI-positive lesions include many lesions with FFR <0.65.

Hybrid Assessment of Myocardial Ischemia Using Stress-Only Nuclear Myocardial Perfusion Imaging and Rest Computed Tomography Perfusion Imaging

BACKGROUND

Sequential assessment using CT coronary angiography (coronary CT) and nuclear myocardial perfusion imaging (MPI) is considered an anatomical and functional evaluation of coronary artery disease (CAD). However, there can be unexpected radiation exposure. Hybrid MPI with stress-only nuclear MPI and rest CT-MPI using coronary CT may contribute to reducing the radiation dose in sequential assessment with nuclear MPI after coronary CT. We analyzed the diagnostic performance and total radiation dose of hybrid MPI for detection of significant CAD compared with sequential assessment using nuclear MPI after coronary CT.

METHODS AND RESULTS

The results for 101 patients who underwent coronary CT, nuclear MPI and invasive coronary angiography within 3 months of all imaging were analyzed. We calculated the summed difference score (SDS) from standard nuclear MPI and hybrid SDS from hybrid MPI, which revealed myocardial ischemia. The diagnostic performance of SDS and hybrid SDS for detecting significant CAD was analyzed using receiver-operating characteristic (ROC) curve analysis. We also compared the total radiation dose of both methods. The area under the ROC curve was not different between SDS and hybrid SDS (0.901 and 0.815, P=0.079). Total radiation dose of hybrid MPI was significantly lower than standard nuclear MPI with CT angiography (4.62 mSv vs. 9.72 mSv, P<0.0001).

CONCLUSIONS

Hybrid MPI showed a precise diagnostic accuracy for significant CAD detection.

Transient ischaemic dilation and post-stress wall motion abnormality increase risk in patients with less than moderate ischaemia: analysis of the REFINE SPECT registry

AIMS

Ischaemia on single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is strongly associated with cardiovascular risk. Transient ischaemic dilation (TID) and post-stress wall motion abnormalities (WMA) are non-perfusion markers of ischaemia with incremental prognostic utility. Using a large, multicentre SPECT MPI registry, we assessed the degree to which these features increased the risk of major adverse cardiovascular events (MACE) in patients with less than moderate ischaemia.

METHODS AND RESULTS

Ischaemia was quantified with total perfusion deficit using semiautomated software and classified as: none (<1%), minimal (1 to <5%), mild (5 to <10%), moderate (10 to <15%), and severe (≥15%). Univariable and multivariable Cox proportional hazard analyses were used to assess associations between high-risk imaging features and MACE. We included 16 578 patients, mean age 64.2 and median follow-up 4.7 years. During follow-up, 1842 patients experienced at least one event. Patients with mild ischaemia and TID were more likely to experience MACE compared with patients without TID [adjusted hazard ratio (HR) 1.42, P = 0.023], with outcomes not significantly different from patients with moderate ischaemia without other high-risk features (unadjusted HR 1.15, P = 0.556). There were similar findings in patients with post-stress WMA. However, in multivariable analysis of patients with mild ischaemia, TID (adjusted HR 1.50, P = 0.037), but not WMA, was independently associated with increased MACE.

CONCLUSION

In patients with mild ischaemia, TID or post-stress WMA identify groups of patients with outcomes similar to patients with moderate ischaemia. Whether these combinations identify patients who may derive benefit from revascularization deserves further investigation.

Prospective diagnostic performance of semiconductor SPECT myocardial perfusion imaging: wall thickening analysis reduces the need for an additional prone acquisition

PURPOSE

To determine whether the assessment of regional wall thickening (WT) in addition to myocardial perfusion from stress supine acquisitions could compensate for the lack of prone acquisition and the corresponding decrease in the diagnostic performance of SPECT myocardial perfusion imaging (MPI) in patients with known or suspected coronary artery disease (CAD).

METHODS

The study group comprised 41 patients (123 vessels) with known or suspected CAD prospectively recruited for systematic prone and supine ²⁰¹Tl stress SPECT MPI. The diagnostic performance of SPECT MPI was determined for various image sets including nongated supine images (supine NG), nongated combined prone and supine images (prone and supine NG) and gated supine images, allowing WT evaluation from NG images in addition to perfusion (supine NG + WT) using invasive coronary angiography and fractional flow reserve as the gold standards.

RESULTS

The rate of false positives was significantly higher among the supine NG images (20.8%) than among either the prone and supine NG or the supine NG + WT images (3.3% and 2.7%, respectively, P < 0.05 vs. supine NG). Consequently, specificity was higher for the prone and supine NG images than for the supine NG images (96.1% vs. 76.1%, P < 0.01) and was highest for the supine NG + WT images (96.8%, P not significant vs. prone and supine NG), without significant differences in sensitivity (80.0%, 86.6% and 73.3%, respectively, P not significant for all comparisons).

CONCLUSION

The diagnostic performance of supine stress SPECT MPI is improved when WT assessment of ischaemic segments is used as an additional diagnostic criterion to values not significantly different from those with combined prone and supine acquisitions.

Correlation between early revascularization and major cardiac events demonstrated by ischemic myocardium in Japanese patients with stable coronary artery disease

BACKGROUND

There is no report on correlation between early revascularization and the occurrence of major cardiac events (MCEs) except severe heart failure in Japanese patients with stable coronary artery disease (CAD). This study aimed to determine whether early revascularization affected the incidence of MCEs in Japanese patients with stable CAD.

METHODS

We retrospectively investigated 3581 stable CAD patients who underwent rest ²⁰¹Tl and stress ^99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography (SPECT) and provided three-year-prognostic data. The endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction, and unstable angina pectoris. On the basis of estimated propensity scores, patients who underwent revascularization within the first 60 days after the SPECT and those who did not were matched in a 1:1 ratio (n=450 per group). We compared MCE rates in relation to the amount of ischemic myocardium detected with the SPECT between the two groups.

RESULTS

The overall incidence of MCEs was not significantly different between the early-revascularization and no-early-revascularization groups (6.7% vs. 8.7%, p=0.2598). Nevertheless, the incidence of MCEs in the patients with ≤5% ischemia was significantly higher in the early-revascularization group than in the no-early-revascularization group (5.8% vs. 0.8%, p=0.0226). In contrast, the incidence of MCEs in the patients with >10% ischemia was significantly lower in the early-revascularization group than in the no-early-revascularization group (7.0% vs. 16.8%, p=0.0036). The incidence of MCEs in the patients with 6-10% ischemia, however, was not significantly different between the early-revascularization and no-early-revascularization groups (6.9% vs. 4.1%, p=0.3235).

CONCLUSIONS

Early revascularization possibly leads to the occurrence of MCEs related to the treatment procedure but may be a therapeutic strategy leading to improvement in prognosis in patients with moderate to severe ischemia.

Clinical Feasibility of Simultaneous Acquisition Rest (99m)Tc/Stress (201)Tl Dual-Isotope Myocardial Perfusion Single-Photon Emission Computed Tomography With Semiconductor Camera

BACKGROUND

The aim of this study was to evaluate the clinical feasibility of simultaneous acquisition of rest (99m)Tc-tetrofosmin/stress (201)Tl dual-isotope single-photon emission computed tomography with a semiconductor gamma camera.

METHODS AND RESULTS

Ninety-four patients with known or suspected coronary artery disease (CAD) were enrolled in the study. First, patients were injected with (99m)Tc-tetrofosmin (296 MBq) for rest imaging, followed by (201)Tl (74 MBq) injection during 6 min of vasodilator stress test. Immediately after the stress test, the patients underwent the first electrocardiogram (ECG)-gated simultaneous acquisition including rest and stress perfusion scans. Patients were brought back for the second simultaneous acquisition for the comparison of ECG-gated wall motion between stress and rest scan 30 min later. Coronary angiography was performed in all the patients within 3 months of this protocol. Sensitivity, specificity and accuracy on a per patient basis to detect significant coronary artery stenosis (≥75%) were 88.6%, 79.2% and 86.2%, respectively. Per coronary vessel, sensitivity, specificity and accuracy were as follows: 84.9%, 80.5% and 83% in the left anterior descending coronary artery; 75%, 93.1% and 86.2% in the left circumflex coronary artery; and 74.2%, 85.7% and 81.9% in the right coronary artery.

CONCLUSIONS

Simultaneous acquisition of rest (99m)Tc-tetrofosmin/stress (201)Tl dual-isotope protocol had high diagnostic accuracy for significant CAD. (Circ J 2016; 80: 689-695).

Major cardiac event risk scores estimated with gated myocardial perfusion imaging in Japanese patients with coronary artery disease

BACKGROUND

A Heart Risk Table has been reported as the first risk score based on nuclear cardiology to predict cardiac event rates in Japanese patients. However, there are no risk scores estimating risk of major cardiac events (MCEs) except severe heart failure.

METHODS

We retrospectively investigated 2579 patients with known or suspected coronary artery disease (CAD) who underwent rest (201)Tl and stress (99m)Tc-tetrofosmin myocardial perfusion single photon emission computed tomography between October 2004 and March 2011 and who had data on a 3-year follow-up. The perfusion images were analyzed with 20 segments of a five-point visual scoring model to estimate summed defect scores. The endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction and unstable angina pectoris.

RESULTS

During the 3-year follow-up, 171 patients (6.6%) experienced MCEs comprising cardiac death (n=78), non-fatal myocardial infarction (n=30), and unstable angina pectoris (n=63). The multivariate logistic regression analysis indicated age, diabetes, estimated glomerular filtration rate (eGFR), and summed stress scores (SSS) as independent predictors of the MCEs and age, stress ejection fraction, eGFR, and SSS as independent predictors of cardiac death. Those four predictors and coefficients corresponding to them were used to make two different risk equations: MCE risk (%/3 years)=1/{1+Exp[-(-3.176+0.018×age+0.602×diabetes-0.022×eGFR+0.051×SSS)]}×100 and cardiac death risk (%/3 years)=1/{1+Exp[-(-2.602+0.031×age-0.031×eGFR+0.038×SSS-0.029×stress ejection fraction)]}×100.

CONCLUSION

The risk scores obtained from this study are useful to predict MCEs in Japanese patients with CAD and are expected to be useful for management and informed consent of high-risk CAD patients.

Significance of worsening renal function and nuclear cardiology for predicting cardiac death in patients with known or suspected coronary artery disease

BACKGROUND

Estimated glomerular filtration rates (eGFRs) at baseline are useful to determine the severity of renal function and to predict cardiac events. However, no studies aimed to demonstrate significance of eGFRs measured during follow-up and usefulness of combination with nuclear cardiology for prediction of cardiac death in patients with coronary artery disease (CAD).

METHODS

We retrospectively investigated 1739 patients with known/suspected CAD who underwent myocardial perfusion single photon emission computed tomography (SPECT), who had eGFRs measured at baseline and after one year and who underwent a three-year follow-up. The SPECT images were analyzed with the visual scoring model to estimate summed defect scores. Reduction in eGFRs (ΔeGFR) was defined as the difference between eGFRs measured after one year and at baseline. The endpoint of the follow-up was cardiac deaths within three years after the SPECT, which were identified with medical records or responses to posted questionnaires.

RESULTS

Cardiac death was observed in 54 of 1739 patients during the follow-up period (45.6±9.1 months). The multivariate Cox regression analysis showed baseline eGFRs, ΔeGFR, and summed stress scores to be significant independent variables for prediction of cardiac death. The area under receiver operating characteristic curves for detection of cardiac death was 0.677 for the baseline eGFR and 0.802 for the follow-up eGFR. Sensitivity of detection of cardiac death was significantly higher in the follow-up eGFR than in the baseline eGFR (p=0.0002). Combination of the best cut-off values, i.e. 9 for the summed stress scores and 10 for the ΔeGFR, which were suggested by receiver operating characteristic analysis, was useful for risk stratification of cardiac death both in patients with and without chronic kidney disease.

CONCLUSION

Baseline and follow-up eGFRs as well as nuclear variables are useful to predict cardiac death in patients with known/suspected CAD.

Myocardial ischemic reduction evidenced by gated myocardial perfusion imaging after treatment results in good prognosis in patients with coronary artery disease

BACKGROUND

There are no nuclear cardiology reports indicating the prediction of prognosis based on ischemic reduction after revascularization in Japanese patients with coronary artery disease (CAD). We aimed to evaluate quantitatively ischemia using myocardial perfusion single photon emission computed tomography (SPECT) before and after treatment such as revascularization and to determine a relationship between the ischemic reduction and the incidence of major cardiac events (MCEs) after the treatment in patients with CAD.

METHODS

We retrospectively investigated 513 patients who underwent rest (201)Tl and stress (99m)Tc-tetrofosmin myocardial perfusion SPECT between October 2004 and March 2011 and who had a significant stenosis with 75% or greater narrowing of the coronary arterial diameter detected by coronary angiography performed after confirmation of ≥5% ischemia with SPECT. The patients underwent the treatment including revascularization and medication and thereafter were re-evaluated with SPECT during a chronic phase and followed up to confirm prognosis for ≥1 year. The follow-up period was 33.4±16.4 months. The endpoint was the incidence of the MCEs consisting of cardiac death, non-fatal myocardial infarction, and unstable angina pectoris.

RESULTS

During the follow-up, 45 patients experienced MCEs comprising cardiac death (n=13), non-fatal myocardial infarction (n=3), and unstable angina pectoris (n=29). The multivariate Cox proportional hazards regression model analysis for the risk of the MCEs showed the changes in the summed difference score % (p=0.0102) and the stress left ventricular ejection fraction after the treatment (p=0.0146) as significant independent variables. The incidence of the MCEs significantly decreased in the patients with ≥5% ischemic reduction than in the patients without ≥5% ischemic reduction and in the patients without residual ischemia than in the patients with the residual ischemia.

CONCLUSION

Myocardial ischemic reduction detected by nuclear cardiology leads to a decrease in MCE rates after treatment in Japanese patients with CAD.

Diagnostic value of automated quantification of nuclear cardiology in Japanese patients with single vessel coronary artery disease: comparison between Japanese and American normal databases

BACKGROUND

The Japanese diagnostic assessment of nuclear cardiology has usually been based on semi-quantitative visual analyses but not on automated quantification with a total perfusion deficit (TPD). We, therefore, aimed to determine whether automated TPD quantification is useful to detect coronary artery disease (CAD) in Japanese patients in comparison with conventional visual segmental analysis, and to compare results from the automated assessment between the Japanese and American normal databases (NDBs).

METHODS

Patients with suspected CAD underwent rest (201)Tl and stress (99m)Tc-tetrofosmin myocardial perfusion single photon emission computed tomography (SPECT) and coronary angiography within three months. The TPD was automatically derived from the SPECT image through quantitative perfusion SPECT software with the Japanese and American NDBs. The visual summed stress scores (SSS) were estimated with the 5-point visual scoring model for 20 segments of SPECT images. An abnormal criteria for the stress TPD and SSS were defined as ≥ 5% and ≥ 4, respectively.

RESULTS

Detection sensitivity of CAD was 87% with the stress TPD score derived from the Japanese NDB and 85% with the SSS in visual analysis. In contrast, the detection sensitivity with the stress TPD score derived from the American NDB was 75%, which was significantly lower than that with the Japanese TPD (p=0.0004). Specificity of the automated Japanese TPD assessment was similar to that of the visual SSS assessment (87% vs. 80%). Thus, sensitivity and specificity of the automated quantitative assessment based on the TPD scores derived from the Japanese NDB were consistent with that of visual quantification based on the segmental defect scores.

CONCLUSION

The automated quantitative assessment with the Japanese NDB is useful for the detection of CAD when experts in visual interpretation of a myocardial perfusion SPECT image were absent in a clinical setting.

Risk stratification of cardiovascular events in patients at all stages of chronic kidney disease using myocardial perfusion SPECT

BACKGROUND

Cardiovascular disease is the leading cause of death among patients with chronic kidney disease (CKD). Therefore, stratification of the prognostic risk of cardiovascular events is useful for their clinical management. We evaluated the ability of electrocardiogram (ECG)-gated myocardial perfusion single photon emission computed tomography (SPECT) to predict cardiac events among Japanese patients at all stages of CKD including those on hemodialysis.

METHODS

Patients with CKD undergoing ECG-gated myocardial perfusion SPECT to investigate suspected ischemic heart disease were followed up to monitor retrospectively major cardiac events including cardiac death, non-fatal myocardial infarction, and unstable angina pectoris. Summed stress score, summed rest score, and summed difference score were estimated with a 20 segment 5-point scoring model. The severity of CKD was divided into five levels based on estimated glomerular filtration rate (eGFR) revised for the Japanese population.

RESULTS

The follow-up period was 25.8 ± 11.0 months. Sixty-two major cardiac events (cardiac death, n=30; non-fatal myocardial infarction, n=13; unstable angina pectoris, n=19) developed in 2243 patients during the first year of follow-up. The findings of multivariate Cox proportional hazards regression analysis indicated that diabetes, eGFR, the summed difference score, and summed stress score were significant independent predictors of cardiac events. The major cardiac event rate at one year increased in proportion to the progression of CKD stage. The major cardiac event-free survival rate decreased steeply over time in patients with CKD stage 5 compared with those who had CKD stages 4 or less.

CONCLUSION

Myocardial perfusion SPECT can contribute to the prediction of cardiac events and survival in patients at all stages of CKD including those on hemodialysis.

Direct quantification of left ventricular motion and thickening changes using rest-stress myocardial perfusion SPECT

Changes in myocardial wall motion and thickening during myocardial perfusion SPECT are typically assessed separately from gated studies for the presence of stress-induced functional abnormalities. We sought to develop and validate a novel approach for automatic quantification of rest-stress myocardial motion and thickening changes (MTCs).

METHODS

Endocardial surfaces at the end-diastolic and end-systolic frames for rest-stress studies were registered automatically to each other by matching ventricular surfaces. Myocardial MTCs were computed, and normal limits of change were determined as the mean and SD for each polar sample. Normal limits were used to quantify the MTCs for each map, and the accumulated sample values were used for abnormality assessments in segmental regions. A hybrid method was devised by combining the total perfusion deficit (TPD) and MTC for each vessel territory. Normal limits were obtained from 100 subjects with low likelihood of coronary artery disease. For validation, 623 subjects with correlating invasive angiography were studied. All subjects underwent a rest-stress (99m)Tc-sestamibi exercise or adenosine test and coronary angiography within 3 months of myocardial perfusion SPECT. All MTC and TPD measurements were derived automatically. The diagnostic accuracy for detection of coronary artery disease for MTC plus TPD was compared with TPD alone.

RESULTS

Segmental normal values were between -1.3 and -4.1 mm for motion change and between -30.1% and -9.8% for thickening change. MTC combined with TPD achieved 61% sensitivity for 3-vessel-disease (3VD), 63% for 2-vessel-disease (2VD), and 90% for 1-vessel-disease (1VD) detection, compared with 32% for 3VD (P < 0.0001), 53% for 2VD (P < 0.001), and 90% for 1VD (P = 1.0) detection using the TPD-alone method. The specificity for the combined method was 71% for 3VD, 72% for 2VD, and 47% for 1VD detection versus 90% for 3VD (P < 0.0001), 80% for 2VD (P < 0.001), and 50% for 1VD detection (P = 0.0625) for the TPD-alone method. The accuracy of 3VD detection by MTC plus TPD was higher (69%) than the accuracy of TPD plus change in ejection fraction (63%) (P < 0.004).

CONCLUSION

We established normal limits and a novel method for computation of regional functional changes between the rest and poststress studies. Compared with TPD alone, the combination of TPD with MTC improved the sensitivity for the detection of 3VD and 2VD.

Combined assessment of myocardial perfusion and function by ECG-gated myocardial perfusion single-photon emission computed tomography for the prediction of future cardiac events in patients with type 2 diabetes mellitus

BACKGROUND

The mid-term prognostic significance of ECG-gated single-photon emission computed tomography (SPECT) remains unclear in Japanese patients with type 2 diabetes mellitus (DM). In the present study rates of future cardiac events (nonfatal acute myocardial infarction (AMI), cardiac death (CD) and severe heart failure (HF) requiring hospitalization) were compared in patients with and without DM.

METHODS AND RESULTS

1,810 patients (563 DM and 1,247 non-DM) we followed for a mean of 26.3±15.5 months. Summed stress score (SSS), summed difference score (SDS), poststress ejection fraction (EF) and resting end-diastolic volume (EDV) were calculated. In total, 20 cases of AMI (9 in DM (1.59%) and 11 in non-DM (0.88%)), 20 of CD (7 in DM patients (1.24%) and 13 in non-DM (1.04%)) and 54 of severe HF (31 in DM (5.5%) and 23 in non-DM (1.84%)) occurred. Univariate Cox analysis showed that, in DM patients, predictors of total cardiac events were poststress EF (Wald 60.4; P<0.001), resting EDV (Wald 53.8; P<0.001), SSS (Wald 39.6; P<0.001), SDS (Wald 26.1; P<0.001), history of prior MI (Wald 4.32; P<0.05) and hemoglobin A(1c) value (Wald 4.30; P<0.05). Multivariate Cox analysis showed that poststress EF (Wald 9.85; P<0.01) and SDS (Wald 6.19; P<0.01) were independent predictors of total cardiac events.

CONCLUSIONS

Combined assessment of perfusion and function by ECG-gated SPECT may predict future cardiac events in type 2 DM patients.

Non-invasive assessment and clinical strategy of stable coronary artery disease by magnetic resonance imaging, multislice computed tomography and myocardial perfusion SPECT

Coronary multislice computed tomography (MSCT) angiography and magnetic resonance angiography (MRA) have emerged as new diagnostic techniques that allow direct visualization of the coronary artery. These new modalities have both advantages and disadvantages concerning radiation exposure, the use of contrast medium, ability of visualizing heavily calcified artery lumens, and spatial and temporal resolution. However, these modalities only provide anatomical information of the coronary artery. Functional assessment of the severity of coronary artery disease (CAD) is essential for the management of patients with known or suspected CAD in practical clinical settings. Myocardial perfusion single-photon emission computed tomography is thought to be the most suitable diagnostic procedure for the determination of therapeutic strategy when coronary MSCT and MRA show significant and also insignificant coronary artery lesions. (Circ J 2010; 74: 34 - 40).

Detection of single-vessel coronary artery disease by dipyridamole stress echocardiography: no longer a problem?

We aimed to evaluate whether addition of myocardial contrast echocardiography (MCE) perfusion data improves the sensitivity of stress echocardiography for detection of single-vessel coronary artery disease (svCAD) and to compare the diagnostic value of MCE and single-photon emission computed tomography (SPECT) for detection of svCAD.

METHODS

One hundred and three patients with suspected or known stable CAD underwent dipyridamole (0.84 mg kg(-1) intravenously over 4 min)-atropine (up to 1 mg intravenously) stress echocardiography combined with MCE. Wall motion abnormalities (WMA) and perfusion defects were assessed visually. Presence of CAD was detected by coronary angiography.

RESULTS

Single-vessel coronary artery disease defined as >or=70% stenosis was detected in 30% of patients, whereas 26% of patients had svCAD defined as >or=50% stenosis. Presence of inducible WMA had 35% and 26% sensitivity for detection of svCAD defined as >or=70% and >or=50% stenosis, respectively. Concomitant evaluation of MCE increased the sensitivity to 74% (P = 0.005) and 56% (P = 0.053), respectively, using any inducible abnormality (WMA or perfusion defects) as a criterion. Presence of any (inducible or fixed) WMA had 77% and 59% sensitivity for detection of svCAD defined as >or=70% and >or=50% stenosis, respectively. In case of such criterion for stress test positivity, the improvement in sensitivity provided by addition of MCE (to 94% and 78%, respectively) did not reach statistical significance.

CONCLUSIONS

Addition of MCE perfusion analysis during stress echocardiographical examination based on evaluation of inducible abnormalities improves the test sensitivity for detection of svCAD. This benefit is less apparent when fixed WMA and perfusion defects are incorporated into the stress test positivity criterion.

Incremental prognostic value of cardiac function assessed by ECG-gated myocardial perfusion SPECT for the prediction of future acute coronary syndrome

BACKGROUND

The prognostic value of ECG-gated rest 201Tl/stress 99mTc-tetrofosmin myocardial perfusion single-photon emission computed tomography for the prediction of acute coronary syndrome (ACS: myocardial infarction (MI) and unstable angina (UA)) and the implications of ejection fraction (EF) has not yet been defined in Japanese.

METHODS AND RESULTS

The 1,895 patients were followed up for the occurrence ACS. The mean follow-up interval was 26.9+/-15.5 months. The 142 patients with revascularization within 60 days were censored. Summed stress score (SSS) and summed difference score (SDS) were calculated. The 19 MI and 29 UA occurred (1.1% and 1.6%, respectively). Univariate Cox analysis showed that hypertension (Wald 5.09, p<0.05), poststress EF (Wald 10.9, p<0.01), SSS (Wald 12.4, p<0.001) and SDS (Wald 18.7, p<0.001) were significant predictors of ACS. Multivariate Cox analysis showed that hypertension (Wald 4.27, p<0.05) and SDS (Wald 8.59, p<0.01) were independent predictors. When multiple clinical risk factors (number of coronary risk factors > or =2), significant ischemia (SDS > or =4) and low EF (EF <45%) were applied to multivariate Cox analysis, the combination of significant ischemia and low EF showed the highest predictive value (Wald 11.9; p<0.001) for future ACS.

CONCLUSION

Poststress EF added incremental prognostic value for the prediction of ACS.

Isolated single coronary artery: a series of 10 cases

BACKGROUND

Isolated single coronary artery (SCA) is an extremely rare congenital coronary anomaly. Some subgroups of SCA can lead to angina pectoris, acute myocardial infarction or even sudden death in the absence of atherosclerosis. Young patients, especially, have the risk of serious clinical events, but middle-aged-to elderly patients have a variable clinical course.

METHODS AND RESULTS

The aim of this study was to present the clinical and angiographic properties, relatively long-term follow-up (54+/-14 months) and management of adult patients (mean age 57+/-12 years) with SCA. The records of 70,850 patients undergoing coronary angiography between 1999 and 2005 were reviewed. Ten patients (0.024%) were found to have SCA, originating from the left sinus of Valsalva in 3 (30%) patients and from the right sinus of Valsalva in 7 patients (70%). No atherosclerotic involvement was seen in 7 (70%) patients. One patient was also treated by stent implantation to the SCA. Other patients were followed medically. All patients have been followed uneventfully.

CONCLUSION

Medical treatment is usually adequate for middle-aged to elderly patients with SCA in the absence of ischemia and/or acute coronary syndrome.

Usefulness of rapid low-dose/high-dose 1-day 99mTc-sestamibi ECG-gated myocardial perfusion single-photon emission computed tomography

BACKGROUND

The clinical usefulness of a rapid rest low-dose/stress high-dose (dose ratio =1:5) (99m)Tc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) protocol for the detection of coronary artery disease was evaluated.

METHODS AND RESULTS

In 89 patients, rest images were obtained immediately after the injection of (99m)Tc-sestamibi (256.1+/-28.4 MBq) followed by drinking water (400 ml). Exercise or vasodilator stress test was performed immediately after the completion of rest imaging with the injection of (99m)Tc-sestamibi (1312.3 +/-167.6 MBq). Prior to the post-stress imaging, patients were asked again to drink water (400 ml) in order to eliminate subdiaphragmatic tracer activity. The myocardial count ratio (stress/rest) of (99m)Tc-sestamibi was calculated. Image quality was scored using a 4-point scale system (4= excellent, 3= good, 2= poor, 1= unacceptable). Coronary angiography was performed in 56 patients within 1 month of the SPECT scan. All patients successfully performed the protocol and total examination time was 108+/-7 min. The myocardial count ratio of (99m)Tc-sestamibi was always greater than 6. The image quality was satisfactory both at rest (3.4+/-0.9) and after stress (3.9+/-0.2). The sensitivity and specificity to detect coronary artery stenosis >50% was 84% and 97%, respectively.

CONCLUSIONS

This rapid one-day (99m)Tc-sestamibi protocol provides adequate image quality and diagnostic accuracy for detecting coronary artery disease.

Prognostic Value of Myocardial Perfusion Single-Photon Emission Computed Tomography for the Prediction of Future Cardiac Events in a Japanese Population A Middle-Term Follow-up Study

BACKGROUND

The prognostic value of rest 201Tl/stress (99m)Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography (SPECT) for the prediction of future hard cardiac events, including acute myocardial infarction (AMI), unstable angina (UAP) and cardiac death, and the implications for risk stratification has not yet been defined in a Japanese population.

METHODS AND RESULTS

The 1,988 patients who underwent rest 201Tl/stress (99m)Tc-tetrofosmin SPECT were identified and followed up for the occurrence of AMI, UAP and cardiac death. The mean follow-up interval was 26.9+/-15.8 months. The 142 patients were revascularized within 60 days after SPECT and they were censored from the prognostic analysis. Summed stress score (SSS), summed rest score and summed difference score (SDS) were calculated using a 5-point scoring (Normal: 0, No uptake: 4) and a 20-segment model; 22 cases of myocardial infarction, 31 of UAP and 22 cardiac deaths occurred (1.2%, 1.7% and 1.2%, respectively). Multivariate Cox regression analysis showed that hypertension (Wald 6.37, p<0.05) and SDS (Wald 8.77, p<0.01) were independent predictors of AMI and UAP. Advanced age (Wald 16.0, p<0.001), SSS (Wald 10.9, p<0.01) and SDS (Wald 4.58, p<0.05) were independent predictors of cardiac death.

CONCLUSION

Myocardial perfusion SPECT yields prognostic information toward the identification of acute coronary syndrome and cardiac death.

Preoperative Risk Stratification With Myocardial Perfusion Imaging in Intermediate and Low-Risk Non-Cardiac Surgery

BACKGROUND

Perioperative cardiac risk in high risk surgery is often stratified with myocardial perfusion single-photon emission computed tomography (SPECT). However, little and no data are available about intermediate and low-risk surgery, respectively.

METHODS AND RESULTS

A total of 1,220 consecutive patients underwent electrocardiography-gated dipyridamole stress SPECT to evaluate myocardial perfusion and cardiac function before intermediate or low risk non-cardiac surgery. Variables predictive of perioperative cardiac events were determined and the usefulness of combining pretest information and the incremental prognostic value of SPECT was estimated. The frequency of all cardiac events depended on clinical risk factors and type of surgical procedures. After sorting the patients with clinical risk factors and surgical risk, assessment of myocardial perfusion or cardiac function yielded significant risk stratification in intermediate, but not in low-risk surgery. Adding functional data to perfusion variables offered an incremental prognostic value for patients with an intermediate clinical risk and scheduled intermediate risk surgery.

CONCLUSIONS

Integrating information about clinical risk factors, type of surgery, myocardial perfusion and cardiac function allows detailed preoperative risk stratification. Preoperative SPECT provides an incremental prognostic value in intermediate, but not in low-risk surgery.

Multislice computed tomographic findings of the anomalous origins of the right coronary artery: evaluation of possible causes of myocardial ischemia

BACKGROUND

Anomalous right coronary arteries (RCA) arising from the left sinus of Valsalva may cause myocardial ischemia.

OBJECTIVE

We evaluated morphological features of anomalous RCA by using multislice computed tomography (MSCT) in relation to myocardial ischemia provoked by myocardial perfusion single-photon emission computed tomography.

METHODS

MSCT was performed in a total of 3, 212 patients by using an Aquillion 16 and a Light Speed Ultra. Retrospective ECG-gated image reconstruction was performed. Volume rendering, axial and curved multiplanar reformatted images were analyzed for the determination of the origin and course of the RCA, the take-off angle of the RCA from the aorta, and size of the RCA orifice. Furthermore, virtual angioscopic images were also used for the evaluation of the RCA orifice structure.

RESULTS

Anomalous origins of the RCA were found in 15 patients. In 13 patients, the RCA arose from the left sinus of Valsalva, and in 2 patients it arose from the left main coronary artery as a single coronary artery. The RCA coursed anteriorly between the ascending aorta and pulmonary artery in 14 patients, whereas it had a retroaortic course in 1 patient. Acute angle take-off (<30 degrees ) of the RCA from the aorta and the left main coronary artery was observed in 8 patients, intramural course of the RCA within the aortic wall was observed in 6 patients and a small RCA orifice was observed in 4 patients. Exercise-induced myocardial ischemia was present in 5 patients.

CONCLUSION

Coursing between the aorta and pulmonary artery, acute angle take-off and intramural course were thought to be major causes of exercise-induced ischemia in patients with anomalous origins of the RCA.

Prognostic value of stress myocardial perfusion imaging in patients with mildly impaired systolic left ventricular function or left ventricular asynergy without chest pain but with suspected coronary artery disease

BACKGROUND

The prognostic value of myocardial perfusion imaging (MPI) was investigated in patients with mildly impaired left ventricular (LV) function who had no chest pain but were suspected to have coronary artery disease (CAD).

METHODS AND RESULTS

Consecutive patients (n=72, mean age =67) who had no chest pain but with mildly impaired systolic LV function (mean LV ejection fraction =52%) or LV asynergy and suspected to have CAD were followed up for 4.9 years after stress MPI. The follow-up time was censored at the occurrence of cardiac death, hospitalization for congestive heart failure (CHF), acute coronary syndromes (ACS), or revascularization. Images were scored using a 20-segment model and a 0-4 scale, and then the summed stress, rest, and difference scores (SDS) were calculated. During follow-up, there were 2 cases of cardiac death, 8 of hospitalization for CHF, 4 of ACS and 2 of revascularization. Cox regression demonstrated that SDS >or=4 was an excellent predictor of cardiac events in all patients (hazard ratio =4.2, p=0.01), and especially in diabetic patients (hazard ratio =28.4, p=0.01).

CONCLUSION

Stress MPI is useful for predicting cardiac events and may be performed in patients without chest pain if they have mildly impaired systolic LV function or LV asynergy.

Efficacy of Multislice Computed Tomography for the Detection of Acute Coronary Syndrome in the Emergency Department

BACKGROUND

The diagnosis of acute coronary syndrome (ACS), especially non-ST-elevation myocardial infarction and unstable angina in the emergency department (ED) still remains a challenge. Multislice computed tomography (MSCT) allows assessment of not only coronary artery stenoses and occlusions, but also assessment of coronary artery plaques and myocardial perfusion status.

METHODS AND RESULTS

MSCT was performed in 31 patients who were admitted to the ED because of chest pain persisting at least 30 min and non-diagnostic ECG changes and normal serum enzyme concentrations. Using MSCT, ACS was defined by coronary artery stenosis > or = 75% accompanied by computed tomography (CT)-low-density plaques, and/or by the presence of myocardial perfusion defects. ACS was confirmed by coronary stenosis > or = 75% by coronary angiography and/or subsequent elevation of troponin I concentration. In total, 22 patients were diagnosed as having ACS. MSCT detected stenoses with CT-low-density plaques in 21 and non-transmural myocardial perfusion defect in 3 patients. There was 1 false-positive and 1 false-negative result. The sensitivity and specificity of MSCT to identify ACS was 95.5% and 88.9%, respectively.

CONCLUSION

MSCT provides diagnostic operating characteristics suitable for triage of patients with ACS in the ED.