Optimal Protocol of Myocardial Perfusion Imaging for Reduction of Radiation Exposure.

The Japanese Circulation Society (JCS) 2021 guideline on radiation safety in cardiology was updated based on the eight best practices for myocardial perfusion single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), which was determined by panels of international atomic energy agency (IAEA) nuclear cardiology protocols cross-sectional study (INCAPS). Although the guideline recommends to avoid too much 201Tl or 201Tl/99mTc dual-isotope protocol, the utilization rate of 201Tl for SPECT-MPI in Japan is considerably high compared to other countries. In Japan, protocols using 99mTc should be appropriately promoted based on the guideline to reduce radiation exposure in SPECT-MPI. Among the eight practices, stress-only imaging is considered to be a useful strategy that contributes to a significant reduction in radiation exposure, and hybrid assessment in combination with rest computed tomography (CT)-MPI is one of the practical application methods.

Association between the health insurance status and clinical outcomes among patients with acute heart failure in Japan.

The relationship between the socioeconomic status, including the health insurance status, and prognosis of heart failure (HF) has been recognized as an important concept for stratifying the risk in HF patients and is gaining increasing attention worldwide even in countries with a universal healthcare system. However, the impact of the Japanese health insurance status on outcomes among patients admitted for acute HF has not been fully clarified. We enrolled 771 patients admitted for acute HF between January 2018 and December 2019 and collected data on the in-hospital mortality, length of the hospital stay, and cardiac events, defined as cardiovascular death and readmission for HF within 1 year after discharge. Patients were divided into two groups according to their insurance status, i.e., public assistance (n = 87) vs. other insurance (n = 684). The public assistance group was significantly younger and had a higher rate of diabetes, smoking, ischemic and hypertensive heart disease, and low estimated glomerular filtration rate (all P < 0.05). Pharmacological/invasive heart failure therapy, in-hospital mortality, and the 90-day cardiac event rate after discharge did not differ between the groups. However, the public assistance group had a significantly higher 1-year cardiac event rate than the other insurance groups (P = 0.025). After adjusting for covariates, public assistance was independently associated with the 1-year cardiac event rate (HR: 2.15, 95% CI: 1.42-3.26, P < 0.001). Acute HF patients covered by public assistance received the same quality of medical care, including invasive therapy. As a result, no health disparities were found in terms of the in-hospital mortality and 90-day cardiac event rate, unlike overseas surveys. Nevertheless, HF patients with public assistance had a higher risk for the long-term prognosis than those with other insurance. Comprehensive HF management is required post-discharge.

High Wall Shear Stress Is Related to Atherosclerotic Plaque Rupture in the Aortic Arch of Patients with Cardiovascular Disease: A Study with Computational Fluid Dynamics Model and Non-Obstructive General Angioscopy.

AIMS: Wall shear stress (WSS) has been considered a major determinant of aortic atherosclerosis. Recently, non-obstructive general angioscopy (NOGA) was developed to visualize various atherosclerotic pathologies, including in vivo ruptured plaque (RP) in the aorta. However, the relationship between aortic RP and WSS distribution within the aortic wall is unclear. This study aimed to investigate the relationship between aortic NOGA-derived RP and the stereographic distribution of WSS by computational fluid dynamics (CFD) modeling using three-dimensional computed tomography (3D-CT) angiography. METHODS: We investigated 45 consecutive patients who underwent 3D-CT before coronary angiography and NOGA during coronary angiography. WSS in the aortic arch was measured by CFD analysis based on the finite element method using uniform inlet and outlet flow conditions. Aortic RP was detected by NOGA. RESULTS: Patients with a distinct RP showed a significantly higher maximum WSS value in the aortic arch than those without aortic RP (56.2±30.6 Pa vs 36.2±19.8 Pa, p=0.017), no significant difference was noted in the mean WSS between those with and without aortic RP. In a multivariate logistic regression analysis, the presence of a maximum WSS value more than a specific value was a significant predictor of aortic RP (odds ratio 7.21, 95% confidence interval 1.78-37.1,p=0.005). CONCLUSIONS: Aortic RP detected by NOGA was strongly associated with a higher maximum WSS in the aortic arch derived by CFD using 3D-CT. The maximum WSS value may have an important role in the underlying mechanism of not only aortic atherosclerosis, but also aortic RP.

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.

Prognostic Significance of the Residual SYNTAX Score and Ischemic Reduction Detected with Nuclear Cardiology for Prediction of Major Cardiac Events after Revascularization.

Objective There is no report on the risk stratification of major cardiac events (MCEs) with a combination of the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score and ischemic reduction detected with rest 201Tl and stress 99mTc-tetrofosmin myocardial perfusion single-photon-emission computed tomography (SPECT) after revascularization in Japanese patients with coronary artery disease (CAD). Methods This was a retrospective study. The patients were followed up to confirm their prognosis for at least one year. Ischemia was evaluated based on the summed difference scores converted to the percentage of the total myocardium Safety Data Sheet (SDS%). The SYNTAX score and SDS% were calculated before and after revascularization. The endpoint was the occurrence of MCEs. Patients Study subjects were 293 patients who had a ≥75% stenotic lesion detected with coronary angiography following confirmation of ≥5% ischemia with SPECT, underwent revascularization, and thereafter received a re-evaluation with SPECT and coronary angiography. Results During the follow-up, 25 patients experienced MCEs of cardiac death (n=2), non-fatal myocardial infarction (n=3), and unstable angina pectoris (n=20). A receiver operating characteristic analysis indicated that the best cut-off values of the residual SYNTAX score and ΔSDS% were 12 and 5%, respectively, for the prediction of MCEs. The patients with a low residual SYNTAX score (<12) and high ΔSDS% (≥5%) had the best prognosis, while those with a high residual SYNTAX score (≥12) and low ΔSDS% (<5%) had the worst prognosis. Conclusion The combination of the residual SYNTAX score and ischemic reduction detected with nuclear cardiology is useful for predicting MCEs after revascularization.

Effect of epicardial fat and metabolic syndrome on reverse atrial remodeling after ablation for atrial fibrillation.

BACKGROUND: Metabolic syndrome/epicardial adipose tissue (EAT) plays an important role in atrial fibrillation (AF). Although reverse atrial remodeling (RAR) often occurs after AF ablation, the effects of EAT on RAR remain unknown. METHODS: Study subjects were 104 patients in whom transthoracic echocardiography (TTE) was performed before AF ablation and 3, 6, and 12 months afterward. EAT was assessed in terms of its thickness adjacent to the right ventricular anterior wall in the TTE parasternal view. RAR was defined as >10% reduction in the left atrial volume (LAV) index by the 3-month follow-up examination. RESULTS: Postablation RAR occurred in 57/104 (55%) patients. RAR absence was associated with a relatively thick EAT (4.92 ± 1.65 vs. 3.92 ± 1.17 mm, P = 0.0005), small LAV index (24.6 ± 7.5 vs. 28.8 ± 10.6 mL/m2, P = 0.0233), and metabolic syndrome (62% vs. 28%, P = 0.0006). Metabolic syndrome and EAT were shown to be independent predictors of RAR absence. Thick EAT was significantly associated with AF recurrence after ablation (5.05 ± 2.19 mm vs. 4.17 ± 1.16 mm for no AF recurrence group, P = 0.0116), but metabolic syndrome was not (48% vs. 42%, P = 0.6189). Despite no change in body weight, EAT thickness decreased significantly by 12 months in patients without AF recurrence (4.17 ± 1.16 vs. 3.65 ± 1.16 mm, P < 0.0001). CONCLUSIONS: EAT and metabolic syndrome appear to be strongly associated with RAR absence, but only the thick EAT was significantly associated with the postablation AF recurrence. Our findings, especially the thinning of EAT, suggest that thick EAT lead to AF vulnerability but that EAT reduction favorably affects ablation outcome.

Influence of balloon temperature and time to pulmonary vein isolation on acute pulmonary vein reconnection and clinical outcomes after cryoballoon ablation of atrial fibrillation.

BACKGROUND: Limited data exist on indicators of durable pulmonary vein isolation (PVI) undergoing cryoballoon ablation (CBA) for atrial fibrillation (AF). We investigated whether balloon temperature and time to PVI can be used to predict early PV reconduction (EPVR), including residual PV conduction and adenosine triphosphate-induced dormant conduction and the relation between touch-up ablation of EPVR sites and mid-term recurrence of AF. METHODS: We obtained procedural and outcome data from the records of 130 consecutive patients who underwent CBA and followed up for 13.4 months. RESULTS: EPVR was identified in 86 (17%) PVs of 61 (47%) patients. Balloon temperatures during 30 seconds (-27 ± 5.7°C vs -31 ± 5.5°C), 60 seconds (-36 ± 5.6°C vs -41 ± 5.4°C), and at the nadir point (-41 ± 7.4°C vs -49 ± 7.0°C) were significantly higher, and the time to PVI was longer (90 ± 50 seconds vs 52 ± 29 seconds) in PVs with EPVR than in those without (P < 0.0001 for all). Among PVs without EPVR, the time to PVI was longer and balloon temperature was lower for the left superior pulmonary vein/ right inferior pulmonary vein (LSPV/RIPV) than for the right superior pulmonary vein/left inferior pulmonary vein (RSPV/LIPV) (time: 60 ± 25/73 ± 37 seconds vs 41 ± 31/45 ± 20 seconds, P < 0.0001) (temp: -39.2 ± 11.3/-39.4 ± 8.3°C vs -33.8 ± 10.6/-33.6 ± 6.8°C, P = 0.0023). AF recurrence rates were equivalent between patients with and without EPVR (13% [8/69] vs 15% [9/61], P = 0.845). CONCLUSIONS: Cryoballoon temperature and time to PVI appear to be useful in predicting durable PVI, that is, prevention of EPVR, but the balloon temperature and time required for PVI differ between PVs. Although EPVR does not predict AF recurrence, high success rates can be expected when touch-up ablation of EPVR sites is performed.

Cardiovascular Outcomes in Patients With Previous Myocardial Infarction and Mild Diabetes Mellitus Following Treatment With Pioglitazone: Reports of a Randomised Trial From The Japan Working Group for the Assessment Whether Pioglitazone Protects DM Patients Against Re-Infarction (PPAR Study).

BACKGROUND: Secondary prevention in patients with myocardial infarction (MI) is critically important to prevent ischaemic heart failure and reduce social burden. Pioglitazone improves vascular dysfunction and prevents coronary atherosclerosis, mainly via anti-inflammatory and antiatherogenic effects by enhancing adiponectin production in addition to antihyperglycemic effects, thus suggesting that pioglitazone attenuates cardiovascular events in patients with mild (HbA1c levels < 6·5%) diabetes mellitus (DM). Therefore, we evaluated the effects of pioglitazone on cardiovascular events in patients with both previous MI and mild DM. METHODS: In this multicentre, prospective, randomised, open, blinded-endpoint trial, we randomly assigned 630 patients with mild DM with a history of MI to undergo either DM therapy with (pioglitazone group) or without (control group) pioglitazone. DM was diagnosed using the 75-g oral glucose tolerance test, and mild DM was defined if HbA1c level was < 6·5%. The primary endpoint was the composite of cardiovascular death and hospitalisation caused by acute MI, unstable angina, coronary revascularisation (including percutaneous coronary intervention and cardiac bypass surgery), and stroke. FINDINGS: HbA1C levels were 5·9 and 5·8% (p = 0·71) at baseline and 6·0 and 5·8% (p < 0·01) at 2 years for the control and pioglitazone groups, respectively.The primary endpoint was observed in 14·2% and 14·1% patients in the control and pioglitazone groups during two years (95% confidential interval (CI):0.662-1·526, p = 0·98), respectively; the incidence of MI and cerebral infarction was 0·3% and 2·2% (95%CI: 0·786-32·415, p = 0·09) and 1·0% and 0·3% (95%CI: 0·051-3·662, p = 0·44), respectively. Post-hoc analyses of the 7-year observation period showed that these trends were comparable (21·9% and 19·2% in the control and pioglitazone groups, 95%CI: 0.618-1·237, p = 0·45). INTERPRETATION: Pioglitazone could not reduce the occurrence of cardiovascular events in patients with mild DM and previous MI.

Diagnostic value of adenosine-induced left ventricular diastolic dysfunction for detecting coronary artery restenosis in patients undergoing stent implantation by Stress ECG-gated myocardial perfusion SPECT. A pilot study.

BACKGROUND: Usefulness of diastolic dysfunction after adenosine stress for detecting coronary stenosis has not been defined. The diagnostic accuracy of a combination of myocardial perfusion and diastolic function, as defined by prolongation of time to peak-filling rate (TTPF)/R-R and myocardial perfusion alone for the detection of coronary restenosis, was evaluated. METHODS AND RESULTS: We used rest (201)Tl/ adenosine stress (99m)Tc-tetrofosmin myocardial perfusion singlephoton emission computed tomography (SPECT) in 70 patients. Patients were divided into the following 4 groups: 20 patients with normal SPECT without stent (Control group), 20 patients showing normal SPECT without coronary restenosis (Group 1), 16 patients showing significant coronary restenosis and myocardial ischemia (Group 2a) and 14 patients showing significant coronary restenosis without myocardial ischemia (Group 2b). The TTPF, which was calculated by quantitative gated SPECT (QGS)/R-R, was not different between after stress and at rest in Control group (0.18±0.02 vs 0.19±0.04, P=NS). The TTPF/R-R after stress was significantly lower than that at rest in Group 1 (0.17±0.02 vs 0.18±0.03, P<0.05), but TTPF/R-R after stress was significantly higher than that at rest in Groups 2a and 2b (0.22±0.03 vs 0.16±0.03, P<0.001 in Group 2a and 0.19±0.02 vs 0.16±0.02, P<0.001 in Group 2b, respectively). Diagnostic accuracy improved from 72% to 92% when prolongation of TTPF/R-R was taken into account (P<0.001). CONCLUSIONS: Diastolic dysfunction after stress was an accurate marker for detecting significant restenosis following stent implantation.

Myocardial necrosis in both left and right ventricles detected by delayed-enhanced magnetic resonance imaging in a patient with isolated noncompaction of the ventricular myocardium.

A 58-year-old man presented with left ventricular failure. Coronary angiography revealed normal coronary arteries and endomyocardial biopsy from the right ventricular apex was normal. Echocardiogram showed marked trabeculation and deep intertrabecular recesses most prominent in the left ventricular apex, anterior and the lateral wall. Cine magnetic resonance imaging showed double-layered appearance on long-axis, 4-chamber and short-axis views. These findings were consistent with isolated noncompaction of the ventricular myocardium (INVM). Gadolinium-diethylenetriomine pentaacetic acid-enhanced imaging revealed delayed enhancement in the both left and right ventricular myocardium.

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.

Myocardial perfusion abnormality and necrosis in a patient with isolated noncompaction of the ventricular myocardium: evaluation by myocardial perfusion SPECT and magnetic resonance imaging.

A 39-year-old woman presented with left ventricular failure. Coronary angiography revealed normal coronary arteries and endomyocardial biopsy from the right ventricular apex was normal. Myocardial perfusion SPECT revealed no perfusion in the inferior wall segment and mild hypoperfusion in the apico-lateral segment. Cine magnetic resonance imaging showed double-layered appearance on 4-chamber view and marked trabeculations and intratrabecular recesses in the infero-lateral segments on short-axis view, findings consistent with isolated noncompaction of the ventricular myocardium (INVM). Contrast-enhanced imaging revealed hypoperfusion and delayed enhancement of the endomyocardium in the anterior and infero-lateral segments. Myocardial perfusion abnormality and necrosis may constitute the diagnostic criteria of INVM.

Coronary artery dissection after blunt chest trauma: depiction at multidetector-row computed tomography.

Coronary artery dissection after blunt chest trauma has rarely been reported in traumatic cardiac injuries, but it may cause fatal or nonfatal myocardial infarction. We report a case of dissection of the left main coronary artery, which resulted in acute myocardial infarction 5 weeks after blunt chest trauma. Multidetector-row computed tomography performed prior to the onset of infarction depicted intimal flap and dissected cavities.

Lipomatous hypertrophy of the interatrial septum presenting as sick sinus syndrome.

Lipomatous hypertrophy of the interatrial septum is a benign cardiac mass characterized by fat accumulation in the interatrial septum. Cardiac arrhythmias including atrial fibrillation, atrial premature contractions and atrioventricular block may occur as a consequence of involvement of the atrial wall and atrioventricular conduction pathways. We describe a patient with lipomatous hypertrophy of the interatrial septum associated with sick sinus syndrome.

Successful treatment of primary cardiac B-cell lymphoma: depiction at multislice computed tomography and magnetic resonance imaging.

Primary cardiac malignant lymphomas are extremely rare and the majority of lymphomas are aggressive B-cell lymphomas. We describe a patient with primary cardiac B-cell lymphoma presenting with superior vena caval syndrome and dyspnea. The tumors manifested as hypoechoic immobile masses on echocardiography, poorly enhancing masses on contrast-enhanced multislice computed tomography and iso-intense masses on T1-weighted and hyper-intense masses on T2-weighted magnetic resonance images. Pathologic examination revealed that the mass was consistent with B-cell malignant lymphoma. Systemic chemotherapy together with monoclonal CD 20 antibody treatment was initiated. There was marked regression of the tumor 4 days after the treatment and complete disappearance of the tumor after 8 days after the treatment without episodes of systemic or pulmonary embolism.