BACKGROUND: Chronic Chagas cardiomyopathy (CCC) is caused by an inflammatory process induced by Trypanosoma cruzi, which leads to myocarditis with reactive and reparative fibrosis. CCC progresses with myocardial perfusion abnormalities and histopathological events that affect cardiorespiratory fitness (CRF).
OBJECTIVE: We evaluated the effects of aerobic physical training (APT) on myocardial perfusion and on morphological and functional impairments related with inflammation and fibrosis in Syrian hamsters with CCC. As a secondary objective, we analyzed the cross-sectional areas of the skeletal muscle.
METHODS: Hamsters with CCC and their respective controls were divided into four groups: CCC sedentary, CCC-APT, sedentary control and APT control. Seven months after infection, the animals underwent echocardiography, myocardial perfusion scintigraphy and cardiopulmonary exercise testing. Moderate-intensity APT was performed for fifty minutes, five times a week, for eight weeks. Subsequently, the animals were reassessed. Histopathological analysis was conducted after the above-mentioned procedures. The level of significance was set at 5% in all analyses (p<0.05).
RESULTS: CCC sedentary animals presented worse myocardial perfusion defects (MPD) over time, reduced left ventricle ejection fraction (LVEF) and showed more inflammation and fibrosis when compared to other groups (mixed ANOVA analysis). Conversely, APT was able to mitigate the progression of MPD, ameliorate inflammation and fibrosis and improve CRF efficiency in CCC-APT animals.
CONCLUSIONS: Our study demonstrated that APT ameliorated cardiac dysfunction, MPD, and reduced inflammation and fibrosis in CCC hamster models. Additionally, CCC-SED animals presented skeletal muscle atrophy while CCC-APT animals showed preserved skeletal muscle CSA. Understanding APT\'s effects on CCC\'s pathophysiological dimensions is crucial for future research and therapeutic interventions.
OBJECTIVE: A Cardiomiopatia Chagásica Crônica (CCC) é causada por um processo inflamatório induzido pelo Trypanosoma cruzi, que leva à miocardite com fibrose reativa e reparativa. A CCC progride com alterações de perfusão miocárdica e eventos histopatológicos que afetam a Aptidão Cardiorrespiratória (ACR).
OBJECTIVE: Avaliamos os efeitos do Treinamento Físico Aeróbico (TFA) na perfusão miocárdica e nos comprometimentos morfológicos e funcionais relacionados à inflamação e fibrose em hamsters sírios com CCC. Como objetivo secundário, analisamos as áreas de secção transversa do músculo esquelético.
UNASSIGNED: Hamsters com CCC e seus respectivos controles foram divididos em quatro grupos: CCC sedentário, CCC-TFA, controle sedentário e controle TFA. Sete meses após a infecção, os animais foram submetidos à ecocardiografia, à cintilografia de perfusão miocárdica e ao teste de esforço cardiopulmonar. TFA de intensidade moderada foi realizado durante cinquenta minutos, cinco vezes por semana, por oito semanas. Posteriormente, os animais foram reavaliados. A análise histopatológica foi realizada após os procedimentos acima mencionados. O nível de significância foi estabelecido em 5% em todas as análises (p<0,05).
RESULTS: Animais com CCC sedentários apresentaram piores Defeitos de Perfusão Miocárdica (DPM) ao longo do tempo, Fração de Ejeção do Ventrículo Esquerdo (FEVE) reduzida, e apresentaram mais inflamação e fibrose quando comparados aos demais grupos (análise ANOVA mista). Por outro lado, o TFA foi capaz de mitigar a progressão do DPM, atenuar a inflamação e a fibrose e melhorar a eficiência da ACR em animais CCC-TFA.
UNASSIGNED: Nosso estudo demonstrou que o TFA melhorou a disfunção cardíaca, DPM e reduziu a inflamação e a fibrose em modelos de hamster com CCC. Além disso, os animais CCC-SED apresentaram atrofia do músculo esquelético, enquanto os animais CCC-TFA apresentaram a AST do músculo esquelético preservada. Compreender os efeitos da TFA nas dimensões fisiopatológicas da CCC é crucial para futuras pesquisas e intervenções terapêuticas.

BACKGROUND: Gated SPECT is an established technique for assessment of left ventricular function in cardiovascular disease patients. However, there is little information about the influence of diabetes mellitus on gated SPECT parameters. This study was established to assess gated SPECT parameters in Diabetes Mellitus (DM) and non-diabetes mellitus (non-DM) patients with normal Myocardial Perfusion Imaging (MPI).
METHODS: In this analytical cross-sectional study, 314 patients (157 DM, 157 non-DM) with normal MPI were enrolled. Prevalence of risk factors for CAD like hypertension (HTN), and dyslipidemia were found to be significantly higher (p <0.01) in DM patients compared to non-DM.
RESULTS: No statistically significant difference was observed among the TID, ESV, EDV, PFR, TTPF, and Wall Thickness (WT) parameters between DM and non-DM patients. Wall motion (Wm) in DM patients was significantly higher compared to non-DM patients. (3.9 ± 0.51 vs. 2.69 ± 0.48 for DM and non-DM patients, respectively, p-value:0.01). Also, there was no significant difference in Wm in the two groups with and without HTN. This shows the independent effect of DM on the Wm.
CONCLUSIONS: This study believes that the Wm parameter should be noted for the early diagnosis or prevention of heart disease in DM patients. These findings can indicate the gradual changes in the movements of the left ventricle and the beginning of the progression of diabetic cardiomyopathy.

OBJECTIVE: Transient ischaemic dilatation (TID) had incremental diagnostic and prognostic value in obstructive coronary artery disease (CAD), but its clinical significance in patients with non-obstructive CAD remains unknown. We aimed to explore the prognostic value of TID in patients with non-obstructive CAD by 13N-ammonia PET imaging.
METHODS: We retrospectively studied 131 consecutive patients with non-obstructive CAD undergoing one-day rest-stress 13N-ammonia PET myocardial perfusion imaging (MPI). TID was automatically generated using CardIQ Physio software. The receiver operative characteristic (ROC) curve was used to determine the optimal threshold of TID. The follow-up outcome was major adverse cardiac events (MACE), a composite of re-hospitalization for heart failure or unstable angina, late revascularization, non-fatal myocardial infarction, and cardiac death. Cardiac event-free survivals for normal and abnormal TID were compared using Kaplan-Meier plots and log-rank tests.
RESULTS: During a median follow-up of 42.08 ± 17.67 months, 22 (16.7%) patients occurred MACE. The optimal cut-off value of TID was 1.03 based on MACE. Our preliminary outcome analysis suggests that TID-abnormal subjects had a lower overall survival probability. Furthermore, our multivariate analysis reveals abnormal TID was the only independent predictor for MACE in non-obstructive CAD. In the subgroup analysis, an abnormal TID was an independent predictor for MACE in patients with abnormal perfusion patterns.
CONCLUSIONS: Among patients with non-obstructive CAD, PET-derived TID ≥ 1.03 may identify those with a high risk of subsequent MACE independently. It was also an independent risk factor for poor prognosis in patients with abnormal perfusion.

暂无摘要。

UNASSIGNED: The value of physiological ischemia versus anatomic severity of disease for prognosis and management of patients with stable coronary artery disease (CAD) is widely debated.
UNASSIGNED: A total of 1764 patients who had rest-stress cadmium-zinc-telluride single-photon emission computed tomography myocardial perfusion imaging and angiography (invasive or computed tomography) were prospectively enrolled and followed for cardiac death/nonfatal myocardial infarction. The CAD prognostic index (CADPI) was used to quantify the extent and severity of angiographic disease. Prognostic value was assessed using Cox models, adjusted for pretest risk, known CAD, stressor, left ventricular ejection fraction, %ischemia and infarct, CADPI, and early (90-day) revascularization. Incremental prognostic value was evaluated using net reclassification index.
UNASSIGNED: The mean age was 69.7±9.5 years, 24.4% were women, and 29.3% had known CAD. Significant ischemia (>10%) was present in 28.4%. Nonobstructive, single, and multivessel disease was present in 256 (14.5%), 772 (43.8%), and 736 (41.7%), respectively. Early revascularization occurred in 579 (32.8%). Cardiac death/myocardial infarction occurred in 148 (8.4%) over a 4.6-year median follow-up. Both %ischemia and CADPI provided independent and incremental prognostic value over pretest clinical risk (P<0.001). In a model containing both ischemia and anatomy, ischemia was prognostic (hazard ratio per 5% ↑, 1.35 [95% CI, 1.11-1.63]; P=0.002) but CADPI was not (hazard ratio per 10-unit ↑, 1.09 [95% CI, 0.99-1.20]; P=0.07). Early revascularization modified the risk associated with %ischemia (interaction P=0.003) but not with CADPI (interaction P=0.6). %Ischemia and single-photon emission computed tomography variables added incremental prognostic value over clinical risk and CADPI (net reclassification index, 20.3% [95% CI, 9%-32%]; P<0.05); however, CADPI was not incrementally prognostic beyond pretest risk, %ischemia, and single-photon emission computed tomography variables (net reclassification index, 3.1% [95% CI, -5% to 15%]; P=0.21).
UNASSIGNED: Ischemic burden provides independent and incremental prognostic value beyond CAD anatomy and identifies patients who benefit from early revascularization. The anatomic extent of disease has independent prognostic value over clinical risk factors but offers limited incremental benefit for prognosis and guiding revascularization beyond physiological severity (ischemia).

暂无摘要。

BACKGROUND: Kidney transplantation provides substantial benefits in extending survival and improving quality of life for patients with end-stage renal disease. The incidence of major adverse cardiac events (MACE) increases with a decline of kidney function in patients with chronic kidney disease. After kidney transplantation, the incidence of MACE remains high. The objective of this study was to assess the prognostic significance of pre-transplant single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in kidney transplant recipients.
METHODS: A systematic literature search was performed between January 1st 2015 and March 26th 2024 in PubMed, EMBASE, Web of Science and The Cochrane Library to identify the prognostic value of SPECT MPI for developing MACE (primary outcome) and mortality (secondary outcome) in kidney transplant recipients (PROSPERO CRD42020188610). Risk of bias was assessed. Meta-analyses and subgroup analyses were performed using random-effects models.
RESULTS: Six studies comprising 2090 SPECT MPI scans were included. Abnormal SPECT MPI scans were associated with an increased risk of MACE post-transplantation (HR 1.62, 95% CI 1.27-2.06, p < 0.001). Subgroup analyses showed consistent findings across various patient populations and methodological differences. Sensitivity analyses supported the robustness of our findings.
CONCLUSIONS: Current evidence showed that pre-transplant SPECT MPI has significant prognostic value in identifying kidney transplant candidates at risk for MACE post-transplantation. Integrating SPECT MPI into preoperative assessments might enhance risk stratification and guide clinical decision-making. Prospective studies are needed to refine risk prediction models.

OBJECTIVE: The aim of this study was to evaluate the performance of myocardial perfusion imaging (MPI) systems in detecting perfusion defects (PDs). The defect perfusion index (DPI) was introduced to extend and further advance the current MPI quality metrics.
METHODS: An anthropomorphic phantom simulating normal and pathological myocardial perfusion conditions was imaged by various NaI-crystal detector systems with and without corrections for scatter (SC) and attenuation (AC) (Symbia, Symbia + SC, Symbia IQ + SCAC, Symbia IQ), and cadmium-zinc-telluride detector systems without corrections (DSPECT, D530c). The extent of PD and the summed score (SS) were obtained by comparing polar maps with ad hoc normal databases created for each MPI system by using phantom polar maps with normal perfusion. The segmental uptake (SU) and the global uniformity (GU) were evaluated. The DPI was calculated on segments included in the PD to minimize attenuation artifacts outside the PD. The 17 segmental model was used.
RESULTS: The highest level of uniformity of polar map was obtained for Symbia IQ + SCAC. D530c showed the highest extent of PD and dependence of the extent on the PD position. It showed in general the lowest SU values and the highest GU due to attenuation artifacts. Nevertheless, D530c outperforms other MPI systems in terms of PD detection, showing the highest DPI value. DSPECT system showed the lowest SS value, and DPI values comparable to NaI-crystal detector systems.
CONCLUSIONS: The DPI can be evaluated to investigate the intrinsic ability of MPI systems to detect PDs, whatever the quantitative post-processing software used.

BACKGROUND: Patients with low HEART (History, Electrocardiogram, Age, Risk factors, and Troponin level) risk scores who are discharged from the emergency department (ED) may present clinical challenges and diagnostic dilemmas. The use of downstream non-invasive stress imaging (NISI) tests in this population remains uncertain. Therefore, this study aims to investigate the value of NISI in risk stratification and predicting cardiac events in patients with low-risk HEART scores (LRHSs).
METHODS: We prospectively included 1384 patients with LRHSs between March 2019 and March 2021. All the patients underwent NISI (involving myocardial perfusion imaging/stress echocardiography). The primary endpoints included cardiac death, non-fatal myocardial infarction and unplanned coronary revascularisation. Secondary endpoints encompassed cardiovascular-related admissions or ED visits.
RESULTS: The mean patient age was 64±14 years, with 670 (48.4%) being women. During the 634±104 days of follow-up, 58 (4.2%) patients experienced 62 types of primary endpoints, while 60 (4.3%) developed secondary endpoints. Multivariable Cox models, adjusted for clinical and imaging variables, showed that diabetes (HR: 2.38; p=0.008), HEART score of 3 (HR: 1.32; p=0.01), history of coronary artery disease (HR: 2.75; p=0.003), ECG changes (HR: 5.11; p<0.0001) and abnormal NISI (HR: 16.4; p<0.0001) were primary endpoint predictors, while abnormal NISI was a predictor of secondary endpoints (HR: 3.05; p<0.0001).
CONCLUSIONS: NISI significantly predicted primary cardiac events and cardiovascular-related readmissions/ED visits in patients with LRHSs.

BACKGROUND: Stress myocardial perfusion single-photon emission computed tomography (SPECT) imaging (MPI) has been used to diagnose and predict the prognoses of patients with coronary artery disease (CAD). An ongoing multicenter collaboration established a Japanese database (J-ACCESS) in 2001 that includes a risk model and expert interpretations. The present study aimed to develop a novel algorithm using machine learning (ML) and resources from the J-ACCESS database to aid SPECT image interpretation.
METHODS: We analyzed data from 1288 patients in J-ACCESS 3 and 4 databases. Three-dimensional (3D) stereoscopic images of left ventricular myocardial perfusion were reconstructed with linear transformation from the original short-axis data. Segments were extracted from U-Net, then features were extracted from each segment during the ML process. We estimated segmental scores based on weighted features obtained from fully connected layers. Correlations between segment scores interpreted by nuclear cardiology experts and estimated by ML were evaluated using a 17-segment model, summed stress (SSS), summed rest (SRS), and summed difference (SDS) scores, and ratios (%) of summed different scores (%SDS).
RESULTS: The complete concordance rate of scores assessed by the experts and estimated by ML was 79.6%. The underestimated and overestimated rates were 10.3% and 10.0%, respectively. Associations between defect scores assessed by experts and ML were close, with correlation coefficients (r) of 0.923, 0.917, 0.842 and 0.853 for SSS, SRS, SDS, %SDS, respectively (p < 0.0001 for all).
CONCLUSIONS: We created a new algorithm to estimate MPI scores using ML and the J-ACCESS database. This algorithm should provide accurate MPI interpretation even in facilities without specialist nuclear cardiologists, and might facilitate therapeutic decision-making and predict prognoses.