The Feasibility of a Model-Based Iterative Reconstruction Technique Tuned for the Myocardium on Myocardial Computed Tomography Late Enhancement.

OBJECTIVES: This study evaluated the feasibility of a model-based iterative reconstruction technique (MBIR) tuned for the myocardium on myocardial computed tomography late enhancement (CT-LE). METHODS: Twenty-eight patients who underwent myocardial CT-LE and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) within 1 year were retrospectively enrolled. Myocardial CT-LE was performed using a 320-row CT with low tube voltage (80 kVp). Myocardial CT-LE images were scanned 7 min after CT angiography (CTA) without additional contrast medium. All myocardial CT-LE images were reconstructed with hybrid iterative reconstruction (HIR), conventional MBIR (MBIR_cardiac), and new MBIR tuned for the myocardium (MBIR_myo). Qualitative (5-grade scale) scores and quantitative parameters (signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]) were assessed as image quality. The sensitivity, specificity, and accuracy of myocardial CT-LE were evaluated at the segment level using an American Heart Association (AHA) 16-segment model, with LGE-MRI as a reference standard. These results were compared among the different CT image reconstructions. RESULTS: In 28 patients with 448 segments, 160 segments were diagnosed with positive by LGE-MRI. In the qualitative assessment of myocardial CT-LE, the mean image quality scores were 2.9 ± 1.2 for HIR, 3.0 ± 1.1 for MBIR_cardiac, and 4.0 ± 1.0 for MBIR_myo. MBIR_myo showed a significantly higher score than HIR (P < 0.001) and MBIR_cardiac (P = 0.018). In the quantitative image quality assessment of myocardial CT-LE, the median image SNR was 10.3 (9.1-11.1) for HIR, 10.8 (9.8-12.1) for MBIR_cardiac, and 16.8 (15.7-18.4) for MBIR_myo. The median image CNR was 3.7 (3.0-4.6) for HIR, 3.8 (3.2-5.1) for MBIR_cardiac, and 6.4 (5.0-7.7) for MBIR_myo. MBIR_myo significantly improved the SNR and CNR of CT-LE compared to HIR and MBIR_cardiac (P < 0.001). The sensitivity, specificity, and accuracy for the detection of myocardial CT-LE were 70%, 92%, and 84% for HIR; 71%, 92%, and 85% for MBIR_cardiac; and 84%, 92%, and 89% for MBIR_myo, respectively. MBIR_myo showed significantly higher image quality, sensitivity, and accuracy than the others (P < 0.05). CONCLUSIONS: MBIR tuned for myocardium improved image quality and diagnostic performance for myocardial CT-LE assessment.

Utility of RAND/UCLA appropriateness method in validating multiple-choice questions on ECG.

OBJECTIVES: This study aimed to investigate the utility of the RAND/UCLA appropriateness method (RAM) in validating expert consensus-based multiple-choice questions (MCQs) on electrocardiogram (ECG). METHODS: According to the RAM user's manual, nine panelists comprising various experts who routinely handle ECGs were asked to reach a consensus in three phases: a preparatory phase (round 0), an online test phase (round 1), and a face-to-face expert panel meeting (round 2). In round 0, the objectives and future timeline of the study were elucidated to the nine expert panelists with a summary of relevant literature. In round 1, 100 ECG questions prepared by two skilled cardiologists were answered, and the success rate was calculated by dividing the number of correct answers by 9. Furthermore, the questions were stratified into "Appropriate," "Discussion," or "Inappropriate" according to the median score and interquartile range (IQR) of appropriateness rating by nine panelists. In round 2, the validity of the 100 ECG questions was discussed in an expert panel meeting according to the results of round 1 and finally reassessed as "Appropriate," "Candidate," "Revision," and "Defer." RESULTS: In round 1 results, the average success rate of the nine experts was 0.89. Using the median score and IQR, 54 questions were classified as " Discussion." In the expert panel meeting in round 2, 23% of the original 100 questions was ultimately deemed inappropriate, although they had been prepared by two skilled cardiologists. Most of the 46 questions categorized as "Appropriate" using the median score and IQR in round 1 were considered "Appropriate" even after round 2 (44/46, 95.7%). CONCLUSIONS: The use of the median score and IQR allowed for a more objective determination of question validity. The RAM may help select appropriate questions, contributing to the preparation of higher-quality tests.

On-Site Computed Tomography-Derived Fractional Flow Reserve Using a Machine-Learning Algorithm　- Clinical Effectiveness in a Retrospective Multicenter Cohort.

BACKGROUND: This study evaluated the diagnostic capability of on-site coronary computed tomography-derived computational fractional flow reserve (CT-FFR) determinations for detecting coronary artery disease (CAD), as assessed by invasive fractional flow reserve (FFR).Methods and Results:Seventy-four patients with coronary artery calcium scores <1,500 who underwent coronary CT angiography (CTA) and invasive FFR measurements within 90 days were retrospectively reviewed. CT-FFR was computed using a prototype machine-learning (ML) algorithm in 91 vessels; 47 vessels of 42 patients were determined to have significant CAD (FFR ≤0.8). Correlation between CT-FFR and FFR was good (r=0.786, P<0.001). Per-vessel area under the curve was significantly larger for CT-FFR (0.907, 95% confidence interval: 0.828-0.958) than for CTA stenosis ≥50% (0.595, 0.487-0.697) or ≥70% (0.603, 0.495-0.705) (both P<0.001). Standard coronary CTA classifications recommended further functional tests in 57 patients with moderate or worse stenosis on CTA. CT-FFR analysis (mean analysis time: 16.4±7.5 min) corrected the standard coronary CTA classification in 18 of 74 patients and confirmed it in 45 of 74 patients. Thus, the per-patient diagnostic accuracy of the classifications was improved from 66% (54-77%) to 85% (75-92%). CONCLUSIONS: On-site CT-FFR based on a ML algorithm can provide good diagnostic performance for detecting hemodynamically significant CAD, suggesting the high value of coronary CTA for selected patients in clinical practice.

Intravascular Ultrasound-Derived Virtual Fractional Flow Reserve for the Assessment of Myocardial Ischemia.

BACKGROUND: Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Intravascular ultrasound (IVUS) is an intracoronary imaging method that provides information about lumen and vessel morphology. Previous studies on the expanded use of IVUS to identify functional ischemia have noted an association between anatomy and physiology, but IVUS-derived minimum lumen area (MLA) has a weak-moderate correlation with myocardial ischemia compared with FFR. We developed a method to calculate FFR using IVUS-derived anatomical information for the assessment of myocardial ischemia. The aims of this study were to investigate the relationship between wire-based FFR and IVUS-derived FFR (IVUS-FFR) and to compare the usefulness of IVUS-FFR and IVUS-derived MLA for functional assessment.Methods and Results:We retrospectively analyzed 50 lesions in 48 patients with coronary stenosis who underwent IVUS and FFR simultaneously. IVUS-FFR was calculated using our original algorithm and fluid dynamics. Mean percent diameter stenosis determined on quantitative coronary angiography and on FFR was 56.4±10.7 and 0.69±0.08, respectively. IVUS-FFR had a stronger linear correlation with FFR (R=0.78, P<0.001; root mean square error, 0.057 FFR units) than with IVUS-derived MLA (R=0.43, P=0.002). CONCLUSIONS: IVUS-FFR may be a more valuable method to identify myocardial ischemia, compared with IVUS-derived MLA.

Prevalence and anatomical features of acute longitudinal stent deformation: An intravascular ultrasound study.

OBJECTIVES: We report the prevalence and anatomical features of longitudinal stent deformation as detected by intravascular ultrasound (IVUS) BACKGROUND: Angiographic studies have recently reported longitudinal stent deformation as a mechanical complication occurring during percutaneous coronary intervention; however, there are no IVUS studies on this phenomenon METHODS: We retrospectively analyzed 1,489 consecutive stent-treated lesions in 1,057 patients who underwent IVUS post-stent implantation RESULTS: Seventeen longitudinal stent deformations in 17 lesions (1.1% per lesion) in 17 patients (1.6% per patient) were identified by IVUS. Of the 17 IVUS-detected deformations, only three deformations (17.6%) were detectable by angiography. By IVUS, there were three patterns of longitudinal stent deformation: (1) Deformation with intra-stent wrinkling and overlapping of the proximal and distal stent fragments within a single stent (n = 14), (2) deformation with elongation (n = 2), and (3) deformation with shortening (n = 1). Most of the deformations were located near to the proximal stent edge (88%), consistent with the finding that they were observed in 11 ostial (65%) and eight left main lesions (47%), and 8.3% of 96 left main stented lesions had evidence of deformation CONCLUSIONS: By IVUS, longitudinal stent deformation during percutaneous coronary intervention was seen more frequently than in previous studies; however, it is still uncommon (1.1%) except in the left main location. The most frequent pattern was intrastent wrinkling and overlapping of the proximal and distal stent fragments.

Utility of Adjunctive Impella Support to Venoarterial Extracorporeal Membrane Oxygenation for a Refractory Electrical Storm.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) stabilizes hemodynamics in an electrical storm leading to cardiogenic shock. However, adverse effects of VA-ECMO are increased left ventricular (LV) afterload and LV end-diastolic pressure due to retrograde blood return. These adverse effects could be ameliorated by LV unloading with Impella insertion. This case illustrates the possible efficacy of adjunctive Impella insertion for a refractory electrical storm that is resistant to defibrillation under mechanical support with VA-ECMO for cardiogenic shock.

Diagnosis of COVID-19: Is Fever the Best Indicator of COVID-19 in Vaccinated SARS-CoV-2-Positive Adults?

OBJECTIVES: Coronavirus disease 2019 (COVID-19) vaccination is highly recommended to prevent the onset and severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Japan. However, the impact of COVID-19 vaccination on the manifestations or presenting symptoms of SARS-CoV-2 infection in daily clinical practice remains unclear. METHODS: This retrospective single-center study was conducted from April 2021 to July 2022 in Japan. We compared the clinical manifestations of SARS-CoV-2 infection in 636 COVID-19-positive patients who visited our outpatient fever clinic, both COVID-19-vaccinated and unvaccinated. RESULTS: During the study period, the COVID-19 vaccination rate at the time of infection was 77.2% (n=491/636), with a median of two doses. Most manifestations, including fever, were reduced in the vaccinated group (n=196) compared to the non-vaccinated group (n=142). The temperature at the clinic decreased significantly as the number of vaccinations increased. Fever was the most common manifestation in the non-vaccinated group (76%, n=108/142), while only 30% (n=59/196) of those who received three or more COVID-19 vaccinations experienced fever. However, sore throat and cough were observed more frequently in the vaccinated group compared to the non-vaccinated group. CONCLUSION: Fever may not be a reliable indicator of SARS-CoV-2 infection in vaccinated individuals, as its frequency is significantly reduced by vaccination. However, since sore throat and cough are more frequently observed in vaccinated individuals, these symptoms could be useful for recommending COVID-19 testing even in the absence of fever, aiding in the prevention of infectious outbreaks.

A prediction model for estimating NT-proBNP in a general Japanese population: the Toon Health Study.

AIMS: As part of the Toon Health Study, which is an ongoing population-based cohort study, we aimed to develop a prediction model for N-terminal pro-brain natriuretic peptide (NT-proBNP) in a general Japanese population. We sought to explore the influence of various demographic and clinical factors on NT-proBNP levels and assess the model's performance. In addition, our objectives included internal validation and investigation of the diagnostic potential of the observed-to-predicted NT-proBNP ratio (OPR) at baseline for predicting the risk of heart failure with preserved ejection fraction (HFpEF). METHODS AND RESULTS: In this prospective cohort study, participants were recruited from Toon City, Japan, as part of the larger Toon Health Study, focusing on cardiovascular risk factors. We measured the NT-proBNP levels and used linear regression with penalization (ridge regression) to develop the model. The model incorporated 10 prespecified predictors (age, gender, body mass index, diastolic blood pressure, heart rate, haemoglobin, albumin, total cholesterol, haemoglobin A1c, and estimated glomerular filtration rate) and underwent assessment using R2 and root mean squared error (RMSE). Internal validation was conducted through bootstrapping. In a post hoc analysis, we explored the OPR's diagnostic potential using 5 year follow-up data (n = 636) to predict the elevation of NT-proBNP > 125 pg/mL at the 5 year follow-up as the risk of HFpEF. A total of 2505 participants (age: 60.4 ± 12.9 years, men: 35%) were enrolled in this study. There was a linear relationship between the observed and predicted values of NT-proBNP in which the logarithm of observed NT-proBNP was <6, which corresponds to 403 pg/mL in NT-proBNP. The prediction model demonstrated satisfactory performance (R2: 0.291, RMSE: 0.688), with age identified as a dominant predictor. The stability of the model was underscored by the internal validation. The OPR at baseline predicted NT-proBNP > 125 pg/mL at the 5 year follow-up with an area under the curve of 0.793. CONCLUSIONS: This study introduces the first prediction model for NT-proBNP in a general Japanese population. Although the model has acceptable performance, ongoing refinement is essential. Our transparent approach to model development, alongside a web-based interactive tool, lays the groundwork for further improvements and external validation. The OPR holds potential for predicting the future risk of HFpEF. This research contributes to understanding the nuanced influence of patient backgrounds on levels of NT-proBNP in asymptomatic individuals within the context of a broader population-based cohort study.

Intravascular Imaging-Based Physiologic Assessment.

Intravascular imaging (IVI), including intravascular ultrasound (IVUS) and optical coherence tomography (OCT), is clinically useful for assessing the luminal size, lesion length, and plaque characteristics, as well as for evaluating stent deployment; however, it is not designed to estimate myocardial ischemia accurately. Thus, several types of IVI-derived fractional flow reserve (FFR) (IVI-derived FFR) have been developed and reported. In general, the algorithms of virtual FFR are based on basic fluid dynamics equations (mainly Poiseuille and Borda-Carnot equations) and original microvascular models (fixed velocity or calculating coronary flow reserve). Although the models and assumptions used in the past reports were mostly based on the standard population (not independent patient data), the developed software calculated FFR with high accuracy (88% to 94%) with strong correlations between IVI-derived FFR and wire-based FFR (0.69 to 0.89). Given several other less invasive virtual FFR methods currently available for clinical use, IVI-derived FFR would be limited for the sole use of pre-percutaneous coronary intervention (PCI) physiological evaluation; however, it may play a unique role at PCI guidance and optimization, potentially allowing comprehensive and time/cost-saving assessment of both anatomical and physiological lesion properties using a single diagnostic device.

Pseudo-hyperacute T Waves in a Giant Hiatal Hernia.

An 89-year-old woman with a giant hiatal hernia complained of persistent chest pain. An electrocardiogram (ECG) showed hyperacute T waves, suggesting the early phase of ST-elevation myocardial infarction. After endoscopic drainage for hiatal hernia, the chest pain disappeared, and the ECG abnormalities resolved. The present case illustrates that compression of the heart by a giant hiatal hernia can induce T wave elevation mimicking acute coronary syndrome.

Protocol for development of an assessment tool for competency of ECG interpretation: expert consensus by the RAND/UCLA appropriateness method and cross-sectional testing using multidimensional item response theory.

INTRODUCTION: Although the ECG is an important diagnostic tool in medical practice, the competency of ECG interpretation is considered to be poor. Diagnostic inaccuracy involving the misinterpretation of ECG can lead to inappropriate medical judgements and cause negative clinical outcomes, unnecessary medical testing and even fatalities. Despite the importance of assessing ECG interpretation skills, there is currently no established universal, standardised assessment tool for ECG interpretation. The current study seeks to (1) develop a set of items (ECG questions) for estimating competency of ECG interpretation by medical personnel by consensus among expert panels following a process based on the RAND/UCLA Appropriateness Method (RAM) and (2) analyse item parameters and multidimensional latent factors of the test set to develop an assessment tool. METHODS AND ANALYSIS: This study will be conducted in two steps: (1) selection of question items for ECG interpretation assessment by expert panels via a consensus process following RAM and (2) cross-sectional, web-based testing using a set of ECG questions. A multidisciplinary panel of experts will evaluate the answers and appropriateness and select 50 questions as the next step. Based on data collected from a predicted sample size of 438 test participants recruited from physicians, nurses, medical and nursing students, and other healthcare professionals, we plan to statistically analyse item parameters and participant performance using multidimensional item response theory. Additionally, we will attempt to detect possible latent factors in the competency of ECG interpretation. A test set of question items for ECG interpretation will be proposed on the basis of the extracted parameters. ETHICS AND DISSEMINATION: The protocol of this study was approved by the Institutional Review Board of Ehime University Graduate School of Medicine (IRB number: 2209008). We will obtain informed consent from all participants. The findings will be submitted for publication in peer-reviewed journals.

Simple Symptom-Based Prediction of COVID-19: A Single-Center Study of Outpatient Fever Clinic in Japan.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) symptoms are not fully understood in non-hospitalized individuals in Japan, and COVID-19 differentiation by symptoms alone remained challenging. Therefore, this study aimed to examine COVID-19 prediction from symptoms using real-world data in an outpatient fever clinic. METHODS: We compared the symptoms of COVID-19-positive and negative patients who visited the outpatient fever clinic at Imabari City Medical Association General Hospital and tested for COVID-19 from April 2021 to May 2022. This retrospective single-center study enrolled 2,693 consecutive patients. RESULTS: COVID-19-positive patients had a higher frequency of close contact with COVID-19-infected patients compared with COVID-19-negative patients. Moreover, patients with COVID-19 had high-grade fever at the clinic compared with patients without COVID-19. Additionally, the most common symptom in patients with COVID-19 was sore throat (67.3%), followed by cough (62.0%), which was approximately twice as common in patients without COVID-19. COVID-19 was more frequently identified in patients having a fever (≥37.5℃) with a sore throat, a cough, or both. The positive COVID-19 rate reached approximately half (45%) when three symptoms were present. CONCLUSION: These results suggested that COVID-19 prediction by combinations of simple symptoms and close contact with COVID-19-infected patients might be useful and lead to recommendations for testing of COVID-19 in symptomatic individuals.