bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Calcium Score's power of zero in 82-Rubidium PET depending on age group and sex
Authors: Frey S , Clerc O F , Amrein M , Thommen K , Leu K , Caobelli F , Haaf P , Zellweger M J 
Published: October 2022

Abstract

Background
Coronary calcium score (CAC) is a well-validated method to detect coronary artery disease (CAD). A significant number of patients referred for functional ischaemia tests reveal a normal result. CAC could be a potential gatekeeper to reduce unnecessary testing.

Purpose
Study aims were to describe the frequency of zero calcium and its diagnostic power to exclude abnormal perfusion stratified by age and sex in a large cohort undergoing 82-Rubidium Positron Emission Tomography (PET).

Methods
All consecutive patients with suspected CAD who were referred for myocardial perfusion PET at our tertiary center between 2016 and 2021 were identified. Baseline and scan related data were extracted from the electronic database. Patients were included for this retrospective analysis if CAC and semi-quantitative analysis of perfusion study were available. Percentiles and test characteristics of zero calcium were calculated stratified by age and sex. Summed stress score (SSS) ≥4 on PET was considered abnormal.

Results
2640 patients were included. Mean age was 65±11 years; 54% were male. Angina and dyspnea were present in 39% and 60%, respectively. 21% (558/2640) of the scans were abnormal and median CAC was 62 [0–374]. 685 patients (26%) had no calcium. Stratified by age, the proportion of zero calcium was 89% (&lt;40 years), 61% (40–49y), 40% (50–59y), 21% (60–69y), 14% (70–79y) and 6% (≥80y). CAC was higher in abnormal scans (median 561 vs. 27, p&lt;0.001) and zero CAC was associated with a lower risk of abnormal PET (2.6% vs. 27.6%, p&lt;0.001). The negative predictive value (NPV) of calcium zero to exclude abnormal PET was 97%, 96% and 98% for all patients, males and females, respectively. Test characteristics are displayed in Table 1. Percentiles of CAC according to scan result are depicted in Figure 1.

Conclusion
The proportion of zero calcium is frequent and declines with increasing age. The absence of coronary calcium is associated with less abnormal PET scans. Zero calcium to exclude an abnormal scan performed best in young patients (&lt;50) with a NPV ≥98%. CAC could act as a gatekeeper. However, further studies including safety endpoints are needed.
The upper calcium score indicates the 90th percentile of patients with normal PET. The lower calcium score indicates the 5th percentile of patients with abnormal PET. Calcium scores within the white area are unlikely to be associated with abnormal PET (since this area includes only the 5% of abnormal PET scans). The dark grey area indicates patients with a high likelihood of positive PET. For better readability, different scales were used.

Funding Acknowledgement
Type of funding sources: None.
Prognostic value of coronary flow capacity derived from [15O]H2O positron emission tomography perfusion imaging
Authors: De Winter R W , Jukema R A , Van Diemen P A , Schumacher S P , Somsen Y B O , Van De Hoef T P , Van Rossum A C , Twisk J W , Maaniitty T , Knuuti J , Saraste A , Nap A , Raijmakers P G , Danad I , Knaapen P 
Published: October 2022

Abstract

Background
Coronary flow capacity (CFC) is a cross-modality framework integrating hyperemic myocardial blood flow (hMBF) and coronary flow reserve (CFR) to quantify the physiological impact of coronary atherosclerotic disease on vasodilator capacity.

Purpose
This study explores the prognostic value of CFC derived from [15O]H2O positron emission tomography (PET) perfusion imaging in addition to traditional perfusion metrics.

Methods
Quantitative perfusion measurements were obtained from 1300 patients with suspected or known coronary artery disease who underwent [15O]H2O PET imaging. Patients were classified as having myocardial steal, severely reduced CFC, moderately reduced CFC, minimally reduced CFC or normal flow using previously defined perfusion thresholds. The endpoint was a composite of death and non-fatal myocardial infarction (MI).

Results
The composite endpoint occurred in 153 (12%) patients during a median follow-up of 5.5 (interquartile range 3.7–7.8) years. Myocardial steal (HR 10.65, 95% CI 4.45–25.49, p&lt;0.001), severely reduced CFC (HR 3.77, 95% CI 1.88–7.58, p&lt;0.001), moderately reduced CFC (HR 2.03, 95% CI 1.25–3.29, p=0.004) and minimally reduced CFC (HR 1.72, 95% CI 1.05–2.81, p=0.030) were independently associated with worse outcome after adjusting for clinical risk factors. Similarly, increased resting MBF (HR 3.19, 95% CI 1.74–5.83, p&lt;0.001), decreased hMBF (HR 0.72, 95% CI 0.57–0.90, p=0.004) and decreased CFR (HR 0.59, 95% CI 0.47–0.73, p&lt;0.001) were significant prognostic factors for events. In a combined perfusion model, only resting MBF (p=0.018) and CFC (overall p=0.012) demonstrated independent prognostic value.

Conclusions
[15O]H2O PET-derived resting MBF, hMBF, CFR and CFC were prognostic factors for death and non-fatal MI. Notably, in a combined model including all perfusion metrics, only resting MBF and CFC were independently associated with adverse outcome.

Funding Acknowledgement
Type of funding sources: None.
Coronary microvascular health in patients with prior COVID-19 infection and no known CAD
Authors: Ahmed A I , Saad J M , Han Y , Alahdab F , Malahfji M , Nabi F , Mahmarian J , Cooke J P , Zoghbi W A , Al-Mallah M H 
Published: October 2022

Abstract

Introduction
Although most patients recovering from acute COVID-19 infection have complete resolution of symptoms, some have cardiopulmonary symptoms lingering long after the acute phase of the disease. One proposed mechanism involves chronicity of COVID-19 associated with myocarditis and endotheliopathy.

Purpose
To determine the coronary microvascular health of patients with prior COVID-19 and no known coronary artery disease (CAD) using positron emission tomography (PET).

Methods
Cases consisting of patients without known CAD but previous COVID-19 infection who had clinically indicated PET imaging were matched 1:4 on clinical and cardiovascular risk factors to controls having no prior COVID-19 infection. Myocardial blood flow (MBF) in ml/gm/min was obtained from dynamic images at rest and peak hyperemia. The coronary flow reserve (CFR) was calculated as the ratio of stress to rest MBF of the left ventricle. Coronary microvascular dysfunction (CMD) was defined as CFR&lt;2.

Results
The study population consisted of 315 patients, 25% (n=80) of which had prior COVID-19 infection (mean±SD age 64±11 years, 46% men). The median (IQR) number of days between COVID-19 infection and PET imaging was 190 (85–268) days. After adjusting for age, gender and cardiovascular risk factors, patients with prior COVID-19 and no known CAD had a statistically significant higher odds of having a CFR &lt;2 (OR 4.9, 95% CI 2.3–10.1 p&lt;0.001) and CFR &lt;2 normalized to patient's rate-systolic blood pressure product (OR 2.8, 95% CI 1.6–5.0 p=0.001). The annualized event rate for the composite outcome of all-cause death, myocardial infarction, admission for heart failure exacerbation and late revascularization was higher in cases vs controls and in those with CMD.

Conclusion
Our analysis showed that patients with prior COVID-19 and no known CAD had higher rates of CMD, and that the presence of CMD was associated with higher risk of incident cardiovascular events.

Funding Acknowledgement
Type of funding sources: None.
Exercise capacity as a predictor of coronary microvascular dysfunction
Authors: Saad J M , Ahmed A I , Alahdab F , Han Y , Alfawara M , Al-Mallah M 
Published: October 2022

Abstract

Introduction
Exercise capacity (EC) is an important prognostic test in patients with coronary artery disease (CAD). Positron-emission tomography (PET) is an important risk-stratifying tool to tailor management of patients with coronary artery disease.

Purpose
We aimed to assess EC in predicting positron emission tomography (PET) myocardial perfusion imaging (MPI) derived coronary flow reserve (CFR).

Methods
Consecutive patients who had clinically indicated PET MPI and EC were included. EC was defined based on peak metabolic equivalents (METS) achieved during exercise stress test. Myocardial blood flow (MBF) in ml/gm/min was obtained from dynamic PET MPI images at rest and peak hyperemia. The coronary flow reserve (CFR) was calculated as the ratio of stress to rest MBF of the left ventricle.

Results
The study population consisted of 511 patients who underwent PET MPI and EC testing (mean age 56 (±11), 71% male). Cardiovascular risk factors were prevalent (75% hypertensive, 82% dyslipidemic, 43% diabetics, 27% known CAD). Peak METS &gt;6 was achieved in 81% of patients, and the CFR &lt;2 was present in 27%. In multivariable logistic regression models adjusted for age, sex, cardiovascular risk factors (hypertension, diabetes, dyslipidemia) and medication use (angiotensin converting enzyme inhibitor/angiotensin receptor blocker, statins, beta-blockers), patients with peak METS &gt;6 had a statistically significant lower odds of microvascular dysfunction (CFR &lt;2: OR 0.43, 95% CI 0.26–0.71, p=0.001). Assessment of discrimination showed the model with CFR &lt;2 had an incremental improvement of Harrell's C statistic over clinical variables (0.65 vs 0.69, p=0.02).

Conclusion
Our findings showed exercise capacity was a good predictor of CFR and microvascular coronary health over and above clinical variables. Further studies are needed to assess the prognostic interplay between EC and CFR.

Funding Acknowledgement
Type of funding sources: None.
Prognostic value of coronary flow reserve and coronary calcification in patients with suspected coronary artery disease
Authors: Alahdab F , Ahmed A I , Saad J M , Han Y , Alfawara M , Al-Mallah M H 
Published: October 2022

Abstract

Introduction
Current cardiac PET and computed tomography imaging allows the simultaneous acquisition of anatomic and physiological data for patients suspected of CAD.

Purpose
We aimed to evaluate the incremental prognostic value of coronary artery calcium (CAC) score and coronary flow reserve (CFR) in patients with suspected coronary artery disease (CAD) undergoing positron emission tomography (PET) myocardial perfusion imaging (MPI).

Methods
We included consecutive patients who underwent PET MPI and CAC score calculation at Houston Methodist Hospital between August 2019 and January 2022. MPI and CAC scores were obtained in the same setting. The primary endpoint of the study was MACE. Cox proportional hazard regression was used to assess the incremental prognostic value of CAC and CFR by sequentially adding the variables to a model that included clinical and PET variables.

Results
A total of 2,072 patients (mean age 65.7±11.6 years, 54.7% women) were included in the analysis. Risk factors were prevalent (86.1% hypertension, 75.2% dyslipidemia, 45.5% diabetes). In total, 25.3% of the cohort had a CAC score of 0, 38.1% had CAC ≥400, and 39.9% had CFR &lt;2. Over a median follow up of 6.26 (IQR 1.7–12.4) months, 66 (3.2%) patients had cardiac death/nonfatal myocardial infarction. CFR score added incremental prognostic value over clinical and perfusion variables alone (base model: c-index 0.75; Akaike information criterion [AIC]: 1,860.6; p&lt;0.001; CFR model: c-index 0.78; AIC: 1,842.4; p=0.041). However, CAC score did not show an increased prognostic utility (CAC model: c-index 0.76; AIC: 1,854.8; p=0.087 vs. base model), and neither did the combined model of CAC and CFR scores (c-index 0.79; AIC: 1,839.4; p=0.366 vs. CFR model).

Conclusions
Among patients referred for PET MPI, CFR score added an increased prognostic value over clinical and MPI variables. However, when evaluating the prognostic utility of CAC alone, or of CAC and CFR combined, the multivariable model did not show any increased prognostic potential.

Funding Acknowledgement
Type of funding sources: None.
Visualization of macrophage inflammatory activity on visceral obesity in high-fat diet-induced obese mice by 18F-FDG PET/CT
Authors: Pahk K , Kwon H W , Kim S 
Published: October 2022

Abstract

Background
Obesity induced inflamed visceral adipose tissue (VAT) secretes pro-inflammatory cytokines thereby promoting systemic inflammation and insulin resistance which further exacerbate obesity-related cardiovascular disease (CVD). Macrophages are the key players in the development of obesity-associated VAT inflammation. Extensive clinical studies have reported that 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) can be used to evaluate the macrophage inflammatory activity on VAT in human beings. However, due to difficulty in human VAT biopsy, pathologic correlations were lacking and there was a few study on preclinical animal models.

Purpose
Here, we investigated whether 18F-FDG PET/CT could reflect the macrophage inflammatory activity on VAT in high-fat diet-induced obese mice.

Methods
Obese animal models were induced by a high-fat diet (60% fat) for 20 weeks using the male C57BL/6 mice. Insulin tolerance test was performed to evaluate the status of insulin resistance and C-reactive protein (CRP) was measured to assess the status of systemic inflammation. All animals underwent 18F-FDG PET/CT before sacrifice. Macrophage inflammatory activity was evaluated using the maximum standardized uptake value (SUVmax). Flow cytometry-, histological-, and molecular analyses were performed on harvested VAT.

Results
All obese animals showed insulin resistance which resembled the human metabolic syndrome, a key pathophysiological process that contributes to increase CVD risk. VAT SUVmax was increased in obese mice and significantly correlated with the levels of CRP. Furthermore, VAT from obese mice showed increased macrophage infiltration, compared to normal mice.

Conclusions
18F-FDG PET/CT could visualize and evaluate the macrophage inflammatory activity on obesity-driven inflamed VAT in obese mice model. Our preclinical study strongly supports the clinical application of 18F-FDG PET/CT in the assessment of VAT inflammation to patients who are vulnerable to CVD.

Funding Acknowledgement
Type of funding sources: None.
The automatic identification of left ventricular chambers and quantification of ejection fraction using a novel artificial intelligence-based system – a validation against cardiac magnetic resonance
Authors: Dindane Z , Sveric K , Winkler A , Botan R , Mierke J , Svitil J , Heidrich F M , Ulbrich S , Linke A 
Published: October 2022

Abstract

Background/Introduction
Cardiac magnetic resonance imaging (CMR) is regarded as the reference method in assessing left ventricular (LV) ejection fraction (EF). However, 2-dimensional echocardiography (2D-Echo) is the most frequently used technique due to availability and practicability. The interpretation of 2D-Echo examinations depends on the user's expertise and may vary between different operators. A novel vendor-independent software based on artificial intelligence (AI) performs both, automated evaluation of 2D-Echo exams and calculations of LV EF in one workflow.

Purpose
We sought to assess the ability of the AI to automatically identify appropriate LV 4- and 2-chamber views (4CV) (2CV) from 2D-Echo exams and validate the resulting EF with CMR.

Methods
We consecutively enrolled 128 patients who underwent clinically indicated CMR examinations and performed a standard 2D-Echo at the same day. The server-based AI solution recognized the optimal LV 4CV and 2CV from 2D-Echo according to quality and depth criteria and automatically performed calculation of biplane EF by endocardial borderline detection. LV EF from CMR and AI were supervised by independent cardiologists blinded to the mutual results. Pearson's correlation (R) and Bland-Altman analysis with limits of agreement (LOA) were performed in order to assess bias between the two methods. Significance was defined as a 2-tailed P value &lt;0.05.

Results
CMR was performed and LV EF was measured in all 128 patients. The median age was 60 years [20–86], 65% were males and CMR was performed due to coronary artery diseases (33%), suspected/florid myocarditis (20%) or further diagnosis of non-ischemic heart failure (47%). Eleven cases (9%) did not pass AI's criteria due to impaired acoustic window or poor 2D-Echo images. The AI system detected either 4CV or 2CV (ratio 1.2) in 13 patients (10%), and both 4CV and 2CV in 104 patients (81% overall feasibility) with a correct classification of 100%. For these 104 patients, excellent correlation was found for AI's biplane LV EF and LV EF from CMR with r=0.91 (p&lt;0.001) (Figure 1, left). However, the absolute mean bias between AI and CMR was 3.5% (p&lt;0.001) and LOAs were −10.6 and +17.5% (Figure 1, right).

Conclusion
The results provided by the AI-based software showed good capabilities and a perfect classification rate to identify 4CV and 2CV. In addition, the LV EF results were excellent compared to CMR, especially since our study did not include “echocardiographically” pre-selected patients. However, differences between AI and CMR measurements are not negligible and warrant further investigation.

Funding Acknowledgement
Type of funding sources: None.
Novel echocardiography-based algorithms to identify severe aortic or mitral regurgitation by cardiac magnetic resonance imaging: a prospective multi-modality imaging study
Authors: Wang T K M , Grimm R A , Popovic Z B , Rodriguez L L , Bolen M A , Chann N , Moennich L A , Rutkowski K , Griffin B P , Flamm S D , Kwon D H 
Published: October 2022

Abstract

Background
Magnetic resonance imaging (MRI) has shown incremental prognostic value to transthoracic echocardiography (TTE) for valve diseases, however TTE remains more widely available and utilized. We sought to develop TTE-based algorithms that best identify severe AR and MR by MRI in a prospective study.

Methods
Patients with &gt;moderate-to-severe AR (n=101) and MR (n=71) undergoing both TTE and CMR within 3-months (median 1 day) were prospectively studied. Correlation analyses were performed, and TTE-based decision tree regression algorithms were derived to best identify CMR-defined severe AR and MR (regurgitant fraction &gt;40% and &gt;33% respectively).

Results
Mean regurgitant volumes/fractions by TTE were 15 mL/18% and 13mL/18% higher than CMR in AR and MR respectively. Decision-tree analyses found regurgitant volume &gt;50 mL and left ventricular end-systolic volume indexed &gt;38 mL/m2 by TTE to best identify CMR-derived severe AR, and regurgitant fraction &gt;50% and left ventricular stroke volume indexed &gt;39 mL/m2 by TTE to best identify CMR-derived severe MR (Figure 1). Their areas under curve compared with current guidelines criteria were 0.75 versus 0.63 (P=0.038) for severe AR, and 0.80 versus 0.67 (P=0.017) for severe MR.

Conclusion
Novel TTE-based algorithms were devised to identify severe MRI-derived AR and MR, superior to the more complex multi-parametric criteria of current TTE guidelines.

Funding Acknowledgement
Type of funding sources: None.
Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving a ventricular fibrillation out of hospital cardiac arrest
Authors: Thomsen A F , Winkel B G , Jons C , Bertelsen L , Bhardwaj P , Stampe N K , Kober L , Engstrom T , Vejlstrup N G , Jacobsen P K 
Published: October 2022

Abstract

Introduction
Prediction of ventricular arrhythmia recurrence in survivors of ventricular fibrillation out of hospital cardiac arrest (VF-OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring and dedicated late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) software allows for characterization of left ventricular scarring, including differentiation between core, border zone (BZ) and BZ channels that represent potential electrical circuits of slow conductivity responsible for ventricular arrhythmic events.

Purpose
Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VF-OCHA and investigate its potential role for the risk of new ventricular arrhythmia.

Methods
Between 2018 and 2021, a total of 130 VF-OHCA patients had CMR, of which we included 28 patients with LGE-CMR before ICD implantation for secondary prevention. A total of 15 (54%) patients had signs of acute or chronic ischemic heart disease (IHD); and 13 (46%) patients had arrhythmogenic cardiomyopathy (ACM). Scar tissue including core, BZ and BZ channels were automatically detected by specialized investigational software. To differentiate BZ from healthy tissue and BZ from core, thresholds of 40% ± 5% and 60% ± 5% of the maximum signal intensity were applied. A BZ channel in the LGE-CMR reconstruction was defined as a continuous corridor of BZ between 2 core areas or between a core area and a valve annulus (Figure 1A+B).

Results
The median age was 56 years; 86% were men and the median left ventricular ejection fraction was 50±11%. A total of 16 (57%) patients had an inferior scar on LGE-CMR, and 8 (29%) patients with IHD were incompletely revascularized. After a median follow-up of 98 days, 9 (32%) patients (6/9 with IHD, including 5/6 incompletely revascularized; 3/9 with ACM) had recurrence of ventricular arrhythmia (6/9 monomorphic ventricular tachycardia (VT)). A significantly higher number of patients with BZ channels had recurrence of ventricular arrhythmia compared with patients without BZ channels (7/11 vs. 2/17; P=0.01) (Figure 2). The number of BZ channels (3±1 vs. 2±1; P=0.13); scar mass (21±8g vs. 14±11g; P=0.21); core mass (7±4g vs. 4±5g; P=0.14); and BZ mass (11±5g vs. 9±7g; P=0.42) were insignificantly higher in patients with recurrent ventricular arrhythmia compared with patients without.

Conclusion
Borderzone channels analyzed by LGE-CMR were associated with subsequent recurrence of ventricular arrhythmia in patients with out of hospital cardiac arrest caused by ventricular fibrillation.

Funding Acknowledgement
Type of funding sources: None.
Higher triglyceride level is associated with the higher prevalence of layered plaque in nonculprit coronary plaques
Authors: Asakura K , Minami Y , Nagata T , Katamine M , Katsura A , Kinoshita D , Ako J 
Published: October 2022

Abstract

Background
The impact of the high triglyceride (TG) level on the characteristics of coronary plaque in nonculprit lesion remains to be elucidated.

Purpose
To clarify the association between the TG level and the characteristics of nonculprit coronary plaque in patients with stable coronary disease using optical coherence tomography (OCT).

Methods
A total of 531 consecutive patients who underwent OCT imaging of the nonculprit lesion were included. Patients were classified into either the higher TG group (non-fasting TG ≥150 mg/dL, n=197) or the lower TG group (non-fasting TG &lt;150 mg/dL, n=334). The morphologies of nonculprit plaque assessed by OCT were compared between the two groups.

Results
The median (interquartile range) of TG in the two groups was 193.0 (168.0–244.0) mg/dL and 95.0 (75.0–120.0) mg/dL, respectively. The prevalence of layered plaque was significantly higher in the higher TG group than the lower TG group (40.1 vs. 27.5%, p=0.004), whereas the prevalence of other plaque components was comparable between the two groups (Figure 1). The prevalence of layered plaque was significantly higher in the higher TG group than in the lower TG group among patients with diabetes mellitus (DM) (44.2 vs. 28.7%, p=0.037) although it was comparable between the two groups among patients without DM (Figure 2).

Conclusion
A higher TG level was associated with a higher prevalence of layered plaque in nonculprit plaques in patients with stable coronary disease, particularly in patients with DM. The present results may partly explain the impact of TG on the progression of coronary plaque and the increased incidence of recurrent events in patients with coronary artery disease.

Funding Acknowledgement
Type of funding sources: None.