Publications by authors named "Calvin Woon-Loong Chin"

Article Synopsis
  • Structural variants (SVs) play a crucial role in genetic differences that relate to traits and diseases, but most research has focused on European populations.
  • This study compiles a catalogue of over 73,000 SVs from a diverse group of 8,392 Singaporeans, revealing that about 65% of these SVs are novel and specific to Asian ancestry groups.
  • The findings help identify clinically relevant SVs and improve genetic research by addressing biases related to ancestry, which is important for equity and diversity in the field.
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Optical coherence tomography angiography (OCTA) has transformed ocular vascular imaging, revealing microvascular changes linked to various systemic diseases. This review explores its applications in diabetes, hypertension, cardiovascular diseases, and neurodegenerative diseases. While OCTA provides a valuable window into the body's microvasculature, interpreting the findings can be complex.

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This study aimed to examine the impact of diabetes and hypertension on retinal nerve fiber layer (RNFL) thickness components. Optical coherence tomography (OCT) measurements do not consider blood vessel contribution, which this study addressed. We hypothesized that diabetes and/or hypertension would lead to thinner RNFL versus controls due to the vascular component.

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Precision medicine promises to transform healthcare for groups and individuals through early disease detection, refining diagnoses and tailoring treatments. Analysis of large-scale genomic-phenotypic databases is a critical enabler of precision medicine. Although Asia is home to 60% of the world's population, many Asian ancestries are under-represented in existing databases, leading to missed opportunities for new discoveries, particularly for diseases most relevant for these populations.

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Background: Consumer-grade wearable devices enable detailed recordings of heart rate and step counts in free-living conditions. Recent studies have shown that summary statistics from these wearable recordings have potential uses for longitudinal monitoring of health and disease states. However, the relationship between higher resolution physiological dynamics from wearables and known markers of health and disease remains largely uncharacterized.

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Background This study examined the associations between quantitative optical coherence tomography angiography (OCTA) parameters and myocardial abnormalities as documented on cardiovascular magnetic resonance imaging in patients with systemic hypertension. Methods and Results We conducted a cross-sectional study of 118 adults with hypertension (197 eyes). Patients underwent cardiovascular magnetic resonance imaging and OCTA (PLEX Elite 9000, Carl Zeiss Meditec).

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Background: The quantitative measures used to assess the performance of automated methods often do not reflect the clinical acceptability of contouring. A quality-based assessment of automated cardiac magnetic resonance (CMR) segmentation more relevant to clinical practice is therefore needed.

Objective: We propose a new method for assessing the quality of machine learning (ML) outputs.

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Multiple studies have compared various optical coherence tomography angiography (OCTA) parameters in participants with systemic hypertension vs. controls and have presented discordant findings. We conducted a meta-analysis to pool together data from different studies to generate an overall effect size and find out whether OCTA parameter(s) significantly differed in participants with systemic hypertension as compared to controls.

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Article Synopsis
  • A study was conducted using non-invasive SS-OCTA to examine the choriocapillaris microvasculature in 41 healthy individuals and 71 hypertensive patients, aiming to find correlations with blood pressure (BP) and kidney function parameters.
  • In hypertensive patients with poorly controlled BP, there were larger and fewer choriocapillaris flow deficits (CFD) compared to those with good BP control and healthy controls.
  • Findings revealed that higher systolic BP, lower estimated glomerular filtration rate (eGFR), and higher urine microalbumin/creatinine ratio (MCR) were linked to larger areas and numbers of CFD, suggesting SS-OCTA could serve as a valuable tool for identifying
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We report a case of coronary artery compression and athlete's heart in a patient with a history of transposition of the great arteries. We present the diagnostic dilemmas and demonstrate the use of cardiac magnetic resonance imaging and cycle-ergometer stress cardiac magnetic resonance in the management of our patient. ().

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Objectives: The imaging features of dilated cardiomyopathy (DCM) overlap with physiological exercise-induced cardiac remodeling in active and otherwise healthy individuals. Distinguishing the two conditions is challenging. This study examined the diagnostic and prognostic roles of exercise stress imaging in asymptomatic patients with suspected DCM.

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Background: Cardiovascular disease (CVD) imposes much mortality and morbidity worldwide. The use of "deep learning", advancements in genomics, metabolomics, proteomics and devices like wearables have the potential to unearth new insights in the field of cardiology. Currently, in Asia, there are no studies that combine the use of conventional clinical information with these advanced technologies.

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Sleep is associated with various health outcomes. Despite their growing adoption, the potential for consumer wearables to contribute sleep metrics to sleep-related biomedical research remains largely uncharacterized. Here we analyzed sleep tracking data, along with questionnaire responses and multi-modal phenotypic data generated from 482 normal volunteers.

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We investigated the characteristics of the choriocapillaris flow voids using optical coherence tomography angiography (OCTA) in 85 patients (164 eyes) with hypertension (mean ± SD age, 56 ± 11 years; 45% women; 20% poorly controlled BP; 16% diabetes) who are without ocular diseases and determined possible correlations with systemic vascular risk factors. Data on 24-hour ambulatory blood pressure (BP), serum creatinine, and urine microalbumin/creatinine ratio (MCR) were collected. Estimated glomerular filtration rate (eGFR) was calculated based on CKD-EPI Creatinine Equation.

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Objective: Reduction in capillary density or rarefaction is a hallmark of essential hypertension. We measured the retinal capillary density using noninvasive optical coherence tomographic angiography (OCT-A) in adults with treated systemic hypertension and determined possible correlations with ambulatory blood pressure (BP) and renal parameters.

Methods: This observational cross-sectional study consisted of 153 normal eyes from 77 nondiabetic hypertensive adults [mean (SD) age, 58 (9) years; 49% women; 23% poorly controlled BP].

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Background: To investigate the biological effect of ageing on intraocular pressure (IOP) and risk factors in a population-based cohort study of Malay and Indian adults.

Methods: Participants aged 40-80 years were recruited for baseline and 6-year follow-up visits between 2004-2009 and 2010-2015, respectively. Blood pressure (BP) was measured with an automatic BP monitor and IOP were obtained by Goldmann applanation tonometry.

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Article Synopsis
  • * Researchers found that individuals could be grouped into clusters based on their daily activities, which reflected different demographic and behavioral traits.
  • * While resting heart rates were more closely linked to cardiovascular and metabolic markers, step counts helped reveal important connections between physical activity and heart health, highlighting the role of wearables in improving personalized health and reducing overdiagnosis in active people.
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Background: Left ventricular (LV) non-compaction (LVNC) is defined by extreme LV trabeculation, but is measured variably. Here we examined the relationship between quantitative measurement in LV trabeculation and myocardial deformation in health and disease and determined the clinical utility of semi-automated assessment of LV trabeculations.

Methods: Cardiovascular magnetic resonance (CMR) was performed in 180 healthy Singaporean Chinese (age 20-69 years; males, n = 91), using balanced steady state free precession cine imaging at 3T.

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Background: Implantable cardioverter defibrillators (ICDs) are lifesaving devices for patients with heart failure (HF) and reduced ejection fraction. However, utilization and determinants of ICD insertion in Asia are poorly defined. We determined the utilization, associations of ICD uptake, patient-perceived barriers to device therapy and, impact of ICDs on mortality in Asian patients with HF.

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The survival benefits of aortic valve replacement (AVR) in the different flow-gradient states of severe aortic stenosis (AS) is not known. A comprehensive search in PubMed/MEDLINE, Embase, Cochrane Library, CNKI and OpenGrey were conducted to identify studies that investigated the prognosis of severe AS (effective orifice area ≤1.0 cm) and left ventricular ejection fraction ≥50%.

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Article Synopsis
  • Vasodilator and dobutamine are the primary drugs used for stress cardiovascular magnetic resonance (CMR), which is essential for assessing heart health.
  • While exercise stress has advantages for other imaging techniques, its use in CMR has been limited due to technical challenges.
  • There is growing interest in exercise stress CMR, which could provide a comprehensive assessment of heart function in one exam, highlighting its potential benefits for various cardiovascular issues.
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Background: Exercise cardiovascular magnetic resonance (ExCMR) has great potential for clinical use but its development has been limited by a lack of compatible equipment and robust real-time imaging techniques. We developed an exCMR protocol using an in-scanner cycle ergometer and assessed its performance in differentiating athletes from non-athletes.

Methods: Free-breathing real-time CMR (1.

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