The 2023 top 10 list of endoscopy topics in medical publishing: an annual review by the American Society for Gastrointestinal Endoscopy Editorial Board

Using a systematic literature search of original articles published during 2023 in Gastrointestinal Endoscopy (GIE) and other high-impact medical and gastroenterology journals, the GIE Editorial Board of the American Society for Gastrointestinal Endoscopy compiled a list of the top 10 most significant topic areas in general and advanced GI endoscopy during the year. Each GIE Editorial Board member was directed to consider 3 criteria in generating candidate topics-significance, novelty, and impact on global clinical practice-and subject matter consensus was facilitated by the Chair through electronic voting and a meeting of the entire GIE Editorial Board. The 10 identified areas collectively represent advances in the following endoscopic spheres: GI bleeding, endohepatology, endoscopic palliation, artificial intelligence and polyp detection, artificial intelligence beyond the colon, better polypectomy and endoscopic mucosal resection, how to make endoscopy units greener, high quality upper endoscopy, endoscopic tissue apposition/closure devices, and endoscopic submucosal dissection. Each board member was assigned a topic area around which summarized relevant important articles, thereby generating this overview of the "top 10" endoscopic advances of 2023.

The association between epidural labour analgesia and postpartum depression: a randomised controlled trial

There is conflicting evidence regarding the association between epidural labour analgesia and risk of postpartum depression. Most previous studies were observational trials with limited ability to account for confounders. We aimed to determine if epidural analgesia was associated with a significant change in the incidence of postpartum depression in this randomised controlled trial. We enrolled women aged 21-50 years old with a singleton fetus ≥ 36 weeks gestation. Patients were advised regarding available labour analgesic modalities during enrolment (epidural block; intramuscular pethidine; nitrous oxide; or intravenous remifentanil). On request for analgesia, patients were offered the modality that they had been allocated randomly to first. Blinded investigators recorded patient and obstetric characteristics within 24 h of delivery and assessed for postpartum depression at 6-10 weeks following delivery using the Edinburgh Postnatal Depression Scale (score ≥ 13 considered positive for postpartum depression). The modified intention-to-treat population consisted of all patients who received any form of labour analgesia, while per-protocol consisted of patients who received their randomised modality as their first form of labour analgesia. Of 881 parturients allocated randomly (epidural n = 441, non-epidural n = 440), we analysed 773 (epidural n = 389, non-epidural n = 384); 62 (15.9%) of women allocated to epidural group developed postpartum depression compared with 65 (16.9%) women allocate to the non-epidural group. There were no significant differences in the incidence of postpartum depression between the two groups (adjusted risk difference (95%CI) 1.6 (-3.0-6.3%), p = 0.49). Similar results were obtained with per-protocol analysis (adjusted risk difference (95%CI) -1.0 (-8.3-6.3%), p = 0.79). We found no significant difference in the risk of postpartum depression between patients who received epidural labour analgesia and those who utilised non-epidural analgesic modalities.

A scientometric analysis of fairness in health AI literature

Artificial intelligence (AI) and machine learning are central components of today's medical environment. The fairness of AI, i.e. the ability of AI to be free from bias, has repeatedly come into question. This study investigates the diversity of members of academia whose scholarship poses questions about the fairness of AI. The articles that combine the topics of fairness, artificial intelligence, and medicine were selected from Pubmed, Google Scholar, and Embase using keywords. Eligibility and data extraction from the articles were done manually and cross-checked by another author for accuracy. Articles were selected for further analysis, cleaned, and organized in Microsoft Excel; spatial diagrams were generated using Public Tableau. Additional graphs were generated using Matplotlib and Seaborn. Linear and logistic regressions were conducted using Python to measure the relationship between funding status, number of citations, and the gender demographics of the authorship team. We identified 375 eligible publications, including research and review articles concerning AI and fairness in healthcare. Analysis of the bibliographic data revealed that there is an overrepresentation of authors that are white, male, and are from high-income countries, especially in the roles of first and last author. Additionally, analysis showed that papers whose authors are based in higher-income countries were more likely to be cited more often and published in higher impact journals. These findings highlight the lack of diversity among the authors in the AI fairness community whose work gains the largest readership, potentially compromising the very impartiality that the AI fairness community is working towards.

Application of a modified tetra-primer ARMS-PCR assay for rapid Panax species identity authentication in ginseng products

Panax ginseng products can be adulterated with materials from other Panax species. The purpose of this study is to provide a rapid P. ginseng authentication method for simultaneous identification of P. ginseng and detection of adulteration in ginseng products at different processing stages. First, a tetra-primer ARMS-PCR assay was designed based on a single-nucleotide polymorphism (SNP) within the trnL-trnF region and was tested at 28 PCR cycles with DNA extracted from Botanical Reference Materials (BRMs). Next, 5' end random nucleotide and 3' terminus phosphorothioates linkage modifications were incorporated into the inner primers to improve sensitivity and specificity at 40 PCR cycles. Finally, the modified assay was validated using characterized market ginseng materials and the detection limit was determined. The modified tetra-primer ARMS-PCR assay can achieve the desired sensitivity and specificity using one set of reaction conditions in ginseng materials at different stages. In validation, it was able to correctly identify target species P. ginseng and differentiate it from closely related species. This study suggests that the modified tetra-primer ARMS-PCR assay can be used for the rapid, species identity authentication of P. ginseng material in ginseng products. This assay can be used to complement chemical analytical methods in quality control, so both species identity and processing attributes of ginseng products can be efficiently addressed.

Machine learning accurately quantifies epicardial adipose tissue from non-contrast CT images in coronary artery disease

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): Industry Alignment Fund – Pre-positioning Programme

Background

Epicardial adipose tissue (EAT) is the visceral fat deposit within the pericardium that surrounds the heart and the coronary arteries. EAT volume measured from non-contrast CT (NCCT) has been demonstrated to be significantly associated with adverse cardiovascular risk,1 particularly in patients with coronary artery disease.2 However, routine measurement of EAT volume is still challenging in clinical practice, as it is a tedious manual process and prone to human error.

Purpose

We aimed to develop a fully automated AI toolkit (i.e., AI EAT) for the quantification of EAT from routine NCCT scans and assess its performance in reference to clinical ground truth.

Methods

This is a multicenter study which performs CT scans in 5000 Asian Admixture patients (APOLLO study NCT05509010). In the current stage of this study, NCCT data analysis were conducted in 551 patients with 26,037 images. AI EAT was developed via a novel deep learning framework using an ensemble region-based UNet. The region-based UNet uses 2 component UNet models to perform segmentation of pericardium at the apex region and non-apex region (middle and basal). EAT volume was obtained by automated thresholding of the voxels (-190 to -30 Hounsfield Unit) within the pericardium (Figure 1). The network was trained in 501 patients with 23,712 NCCT images and tested in 50 patients with 2,325 NCCT images. The performance of AI EAT was evaluated with respect to clinical ground truth using Dice similarity coefficient (DSC), Pearson correlation, and Bland-Altman analysis.

Results

The AI EAT quantification process took less than 10 seconds per subject, compared with 20-30 minutes for expert readers. Compared to clinical ground truth, our AI EAT achieved a DSC of 0.96±0.01 and 0.91±0.02 for pericardium and EAT segmentations, respectively. There was strong agreement between the AI EAT and clinical ground truth in deriving the EAT volume (r=0.99, P<0.001) with minimal error of 7±5%.

Conclusion

End-to-end deep learning system accurately quantifies epicardial adipose tissue in standard NCCT images without manual segmentation.

Outcomes for endoscopic submucosal dissection of pathologically staged T1b esophageal cancer: a multicenter study

BACKGROUND AND AIMS

The outcomes of endoscopic submucosal dissection (ESD) for T1b esophageal cancer (EC) and its recurrence rates remain unclear in the West. Using a multicenter cohort, we evaluated technical outcomes and recurrence rates of ESD in the treatment of pathologically staged T1b EC.

METHODS

We included patients who underwent ESD of T1b EC at 7 academic tertiary referral centers in the United States (n = 6) and Brazil (n = 1). We analyzed demographic, procedural, and histopathologic characteristics and follow-up data. Time-to-event analysis was performed to evaluate recurrence rates.

RESULTS

Sixty-six patients with pathologically staged T1b EC after ESD were included in the study. A preprocedure staging EUS was available in 54 patients and was Tis/T1a in 27 patients (50%) and T1b in 27 patients (50%). En-bloc resection rate was 92.4% (61/66) and R0 resection rate was 54.5% (36/66). Forty-nine of 66 patients (74.2%) did not undergo surgery immediately after resection and went on to surveillance. Ten patients had ESD resection within the curative criteria, and no recurrences were seen in a 13-month (range, 3-18.5) follow-up period in these patients. Ten of 39 patients (25.6%) with noncurative resections had residual/recurrent disease. Of the 10 patients with noncurative resection, local recurrence alone was seen in 5 patients (12.8%) and metastatic recurrence in 5 patients (12.8%). On univariate analysis, R1 resection had a higher risk of recurrent disease (hazard ratio, 6.25; 95% confidence interval, 1.29-30.36; P = .023).

CONCLUSIONS

EUS staging of T1b EC has poor accuracy, and a staging ESD should be considered in these patients. ESD R0 resection rates were low in T1b EC, and R1 resection was associated with recurrent disease. Patients with noncurative ESD resection of T1b EC who cannot undergo surgery should be surveyed closely, because recurrent disease was seen in 25% of these patients.

Endoscopic submucosal dissection vs. endoscopic mucosal resection for early Barrett's neoplasia in the West: a retrospective study

BACKGROUND

The difference in clinical outcomes after endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) for early Barrett's esophagus (BE) neoplasia remains unclear. We compared the recurrence/residual tissue rates, resection outcomes, and adverse events after ESD and EMR for early BE neoplasia.

METHODS

We included patients who underwent EMR or ESD for BE-associated high grade dysplasia (HGD) or T1a esophageal adenocarcinoma (EAC) at eight academic hospitals. We compared demographic, procedural, and histologic characteristics, and follow-up data. A time-to-event analysis was performed to evaluate recurrence/residual disease and a Kaplan-Meier curve was used to compare the groups.

RESULTS

243 patients (150 EMR; 93 ESD) were included. EMR had lower en bloc (43 % vs. 89 %; P < 0.001) and R0 (56 % vs. 73 %; P = 0.01) rates than ESD. There was no difference in the rates of perforation (0.7 % vs. 0; P > 0.99), early bleeding (0.7 % vs. 1 %; P > 0.99), delayed bleeding (3.3 % vs. 2.1 %; P = 0.71), and stricture (10 % vs. 16 %; P = 0.16) between EMR and ESD. Patients with non-curative resections who underwent further therapy were excluded from the recurrence analysis. Recurrent/residual disease was 31.4 % [44/140] for EMR and 3.5 % [3/85] for ESD during a median (interquartile range) follow-up of 15.5 (6.75-30) and 8 (2-18) months, respectively. Recurrence-/residual disease-free survival was significantly higher in the ESD group. More patients required additional endoscopic resection procedures to treat recurrent/residual disease after EMR (EMR 24.2 % vs. ESD 3.5 %; P < 0.001).

CONCLUSIONS

ESD is safe and results in more definitive treatment of early BE neoplasia, with significantly lower recurrence/residual disease rates and less need for repeat endoscopic treatments than with EMR.

Recent Advances in Endoscope Disinfection: Where Do We Stand in the COVID era?

Over 16 million cases worldwide, severe acute respiratory syndrome coronavirus 2 has profoundly affected healthcare as we know it. Given reports of gastrointestinal involvement and viral shedding in the stool, it is unsurprising there are concerns that endoscopic equipment may be a potential vector of viral transmission. Here, we provide an overview of existing practices for endoscope reprocessing, recent developments in the field, and challenges in the COVID-19 environment. Current multi-society guidelines do not advise any change to endoscope disinfection protocols but emphasize strict adherence to recommended practices. However, endoscopy reprocessing staff may benefit from supplemental personal protective equipment measures, especially in high risk situations. Because thorough endoscope reprocessing is highly operator dependent, adequate training of personnel is critical for proper manual cleaning and disinfection of endoscopes that have potential to harbor virus. Bacterial contamination of duodenoscopes has caused outbreaks of infection from multidrug-resistant organisms, highlighting vulnerable areas. The emphasis of current studies is on optimization of disinfection and drying, minimization of simethicone use, and on quality control of endoscope reprocessing with sampling and microbiological culturing. Recent advances include novel approaches to endoscope sterilization, infection barrier methods, and design of partially or fully disposable duodenoscopes. Overall, the available data indicate that, when correctly executed, current reprocessing practices are sufficient in preventing SARS-COV-2 transmission.

Field Identification of Matricaria chamomilla using a Portable qPCR System

Quality control in botanical products begins with the raw material supply. Traditionally, botanical identification is performed through morphological assessment and chemical analytical methods. However, the lack of availability of botanists, especially in recent years, coupled with the need to enhance quality control to combat the stresses on the supply chain brought by increasing consumer demand and climate change, necessitates alternative approaches. The goal of this protocol is to facilitate botanical species identification using a portable qPCR system on the field or in any setting, where access to laboratory equipment and expertise is limited. Target DNA is amplified using dye-based qPCR, with DNA extracted from botanical reference materials serving as a positive control. The target DNA is identified by its specific amplification and matching its melting peak against the positive control. A detailed description of the steps and parameters, from hands-on field sample collection, to DNA extraction, PCR amplification, followed by data interpretation, has been included to ensure that readers can replicate this protocol. The results produced align with traditional laboratory botanical identification methods. The protocol is easy to perform and cost-effective, enabling quality testing on raw materials as close to the point of origin of the supply chain as possible.

Validation of a Targeted PCR Method for Raw and Processed Botanical Material Identification: An Example Using Matricaria chamomilla (Chamomile)

Background: A requirement of current good manufacturing practices for dietary supplements is that manufacturers must identify their dietary ingredients. DNA-based methods can provide species-level authentication that may sometimes be difficult to achieve using conventional morphological and chemical analysis methods. However, because of varying levels of DNA degradation in botanical materials, many commercial tests fail to generate consistent test results across all types of botanical materials. AOAC published guidelines for validation of botanical identification methods and proposed probability of identification (POI) as a method performance parameter. However, few DNA-based botanical authentication methods in the literature follow these guidelines and evaluate POI. Objective: To provide a targeted PCR method validation example that follows AOAC guidelines for validation of botanical identification methods. Methods: Using Matricaria chamomilla (chamomile) as an example, we performed a single-laboratory validation for a targeted PCR method that aimed to identify both raw and processed chamomile materials. The performance parameters of the test were evaluated by carrying out an inclusivity/exclusivity study and a Specified Superior Test Material/Specified Inferior Test Material study to demonstrate that the method’s POI meets industry requirements. Results: The chamomile samples were identified by the method and achieved a POI greater than 0.9 with respect to all types of chamomile botanical materials. Conclusions: The method was validated for DNA-based identification of raw and processed chamomile materials, such as sterilized powders and extracts. Highlights: This work will provide insight for laboratories and manufacturers that aim to develop and validate DNA-based botanical identification methods.

Validation of a Targeted PCR Method for Raw and Processed Botanical Material Identification: An Example Using Matricaria chamomilla (Chamomile)

Background: A requirement of current good manufacturing practices for dietary supplements is that manufacturers must identify their dietary ingredients. DNA-based methods can provide species-level authentication that may sometimes be difficult to achieve using conventional morphological and chemical analysis methods. However, because of varying levels of DNA degradation in botanical materials, many commercial tests fail to generate consistent test results across all types of botanical materials. AOAC published guidelines for validation of botanical identification methods and proposed probability of identification (POI) as a method performance parameter. However, few DNA-based botanical authentication methods in the literature follow these guidelines and evaluate POI. Objective: To provide a targeted PCR method validation example that follows AOAC guidelines for validation of botanical identification methods. Methods: Using Matricaria chamomilla (chamomile) as an example, we performed a single-laboratory validation for a targeted PCR method that aimed to identify both raw and processed chamomile materials. The performance parameters of the test were evaluated by carrying out an inclusivity/exclusivity study and a Specified Superior Test Material/Specified Inferior Test Material study to demonstrate that the method’s POI meets industry requirements. Results: The chamomile samples were identified by the method and achieved a POI greater than 0.9 with respect to all types of chamomile botanical materials. Conclusions: The method was validated for DNA-based identification of raw and processed chamomile materials, such as sterilized powders and extracts. Highlights: This work will provide insight for laboratories and manufacturers that aim to develop and validate DNA-based botanical identification methods.

P1925Machine learning versus classic electrocardiographic criteria for left ventricular hypertrophy in a young pre-participation cohort: results from the SAFE protocol study

Background/Introduction

Classic electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) have been well studied in Western populations, particularly in hypertensive patients. However, their utility in Asian populations is not well studied, and their applicability to young pre-participation cohorts is unclear. We sought to evaluate the performance of classical criteria against that of machine learning models.

Aims

We sought to evaluate the performance of classical criteria against the performance of novel machine learning models in the identification of LVH.

Methodology

Between November 2009 and December 2014, pre-participation screening ECG and subsequent echocardiographic data was collected from 13,954 males aged 16 to 22, who reported for medical screening prior to military conscription.

Final diagnosis of LVH was made on echocardiography, with LVH defined as a left ventricular mass index >115g/m2. The continuous and binary forms of classical criteria were compared against machine learning models using receiver-operating characteristics (ROC) curve analysis. An 80:20 split was used to divide the data into training and test sets for the machine learning models, and three fold cross validation was used in training the models. We also compared the important variables identified by machine learning models with the input variables of classical criteria.

Results

Prevalence of echocardiographic LVH in this population was 0.91% (127 cases). Classical ECG criteria had poor performance in predicting LVH, with the best predictions achieved by the continuous Sokolow-Lyon (AUC = 0.63, 95% CI = 0.58–0.68) and the continuous Modified Cornell (AUC = 0.63, 95% CI = 0.58–0.68). Machine learning methods achieved superior performance – Random Forest (AUC = 0.74, 95% CI = 0.66–0.82), Gradient Boosting Machines (AUC = 0.70, 95% CI = 0.61–0.79), GLMNet (AUC = 0.78, 95% CI = 0.70–0.86). Novel and less recognized ECG parameters identified by the machine learning models as being predictive of LVH included mean QT interval, mean QRS interval, R in V4, and R in I.

ROC curves of models studies

Conclusion

The prevalence of LVH in our population is lower than that previously reported in other similar populations. Classical ECG criteria perform poorly in this context. Machine learning methods show superior predictive performance and demonstrate non-traditional predictors of LVH from ECG data. Further research is required to improve the predictive ability of machine learning models, and to understand the underlying pathology of the novel ECG predictors identified.

Single-Laboratory Validation of a Two-Tiered DNA Barcoding Method for Raw Botanical Identification

Background: The applications of deoxyribonucleic acid (DNA) barcoding methods have been extended from authenticating taxonomic provenance of animal products to identifying botanicals used as herbal medicine and in botanical dietary supplements. DNA barcoding methods for botanical identification must be adequately validated to meet regulatory compliance. Objective: The goal of this study is to provide a validation protocol for a two-tiered DNA barcoding method that aims to identify raw botanicals. Methods: A barcode database was computationally validated to define the barcode combinations that can unambiguously identify botanicals in the database. A maximum variation sampling technique was used to capture a wide range of perspectives relating to DNA barcode-based botanical identification, including plant parts and species distance, for the experimental validation. Twenty-two authenticated botanicals were purposively sampled from different plant parts—covering both closely related and distantly related species—to validate the two-tiered DNA barcoding method. The performance of the method was assessed on accuracy, precision, ruggedness, and uncertainty. Results: High accuracy (100%) and precision (1.0) were obtained from the validation samples. The method was also found to be rugged and have acceptable uncertainty. Conclusions: The method was validated and suitable for DNA-based identification of botanical raw materials listed in the current database. Highlights: This work will provide support guidance for manufacturers and regulatory policy makers to implement equivalent validated and compliant DNA-based testing in quality control processes to improve botanical raw material identification and authentication.

Endoscopic Ultrasound-Guided Ablation of Liver Tumors

"Endoscopic ultrasound (EUS)-guided ablative therapies have advanced significantly and have led to experimental applications in locations that have been difficult to image and/or reach with percutaneous approaches, such as the caudate and left lobe of the liver. EUS-guided treatments of the liver are under development. The literature has shown that many percutaneous ablative techniques are readily adaptable for EUS. In this review, the authors discuss the current developments on EUS-guided ablation of liver tumors, including injection of sclerosants, thermal therapy, and EUS-guided portal injection of chemotherapy."

Acute pancreatitis patient registry to examine novel therapies in clinical experience (APPRENTICE): an international, multicenter consortium for the study of acute pancreatitis

Background

We have established a multicenter international consortium to better understand the natural history of acute pancreatitis (AP) worldwide and to develop a platform for future randomized clinical trials.

Methods

The AP patient registry to examine novel therapies in clinical experience (APPRENTICE) was formed in July 2014. Detailed web-based questionnaires were then developed to prospectively capture information on demographics, etiology, pancreatitis history, comorbidities, risk factors, severity biomarkers, severity indices, health-care utilization, management strategies, and outcomes of AP patients.

Results

Between November 2015 and September 2016, a total of 20 sites (8 in the United States, 5 in Europe, 3 in South America, 2 in Mexico and 2 in India) prospectively enrolled 509 AP patients. All data were entered into the REDCap (Research Electronic Data Capture) database by participating centers and systematically reviewed by the coordinating site (University of Pittsburgh). The approaches and methodology are described in detail, along with an interim report on the demographic results.

Conclusion

APPRENTICE, an international collaboration of tertiary AP centers throughout the world, has demonstrated the feasibility of building a large, prospective, multicenter patient registry to study AP. Analysis of the collected data may provide a greater understanding of AP and APPRENTICE will serve as a future platform for randomized clinical trials.

Hyoscine butylbromide administered at the cecum increases polyp detection: a randomized double-blind placebo-controlled trial

BACKGROUND AND STUDY AIMS

Removal of colonic polyps prevents progression of colonic neoplasia. Miss rates of polyps range from 5 % to 32 %. The effect of colonic contractility on polyp detection has not been studied adequately. Hyoscine butylbromide results in colonic spasmolysis and may improve polyp detection.

PATIENTS AND METHODS

Patients undergoing colonoscopy for standard indications were included and randomized to receive either 20  mg hyoscine butylbromide or placebo at cecal intubation. Operators were blind to the intervention. Data on indication, preparation, sedation, colonoscope type, times of insertion/withdrawal, polyps, and failure were recorded. The primary end point was the number of polyps detected per patient. Secondary endpoints were adenoma detection rate and polyp detection rate.

RESULTS

A total of 303 patients received hyoscine butylbromide and 298 received placebo. More polyps per patient were identified in the hyoscine group than in the placebo group (0.91 vs. 0.70; P = 0.044). Adenoma detection rate and polyp detection rate were higher in the hyoscine arm but not significantly different (27.1 % vs. 21.8 % [P = 0.13] and 43.6 % vs. 36.6 % [P = 0.08], respectively). After adjusting for confounding variables, the odds of detecting any polyp were 1.56 higher in the hyoscine than the placebo group (95 % confidence interval [CI] 1.09 - 2.21, P = 0.014). The adjusted odds of detecting any adenoma were 1.62 higher in the hyoscine group compared with the placebo group (95 %CI 1.09 - 2.42, P = 0.017). There were no differences in baseline characteristics between the groups. No adverse colonoscopy-related events were recorded. One patient experienced transient tachycardia without sequelae.

CONCLUSIONS

Hyoscine butylbromide administered at the cecum aids polyp detection. Further studies are required to determine the contribution of colonic spasm to polyp miss rates.

New techniques in imaging in Barrett's esophagus

The presence of dysplasia in patients with Barrett's esophagus identifies who is at increased risk for the development of esophageal adenocarcinoma and who may most benefit from intervention. Several technologies have emerged as potent tools to identify subtle or occult neoplasia in the gastrointestinal tract. Detailed inspection of the mucosa with high resolution white light endoscopy is the most critical tool to detect subtle neoplasia. This review also chromoendoscopy, narrow band imaging, autofluorescence imaging, optical coherence tomography, confocal laser endomicroscopy, and spectroscopy in the context of detection of neoplasia in Barrett's esophagus.

Ministry of health clinical practice guidelines: screening of cardiovascular disease and risk factors

The Ministry of Health (MOH) publishes clinical practice guidelines on Screening of Cardiovascular Disease and Risk Factors to provide doctors and patients in Singapore with evidence-based guidance on the screening of cardiovascular disease and risk factors. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Screening of Cardiovascular Disease and Risk Factors, for the information of readers of the Singapore Medical Journal. Page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=25776). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Impact of surgical ventricular restoration on ventricular shape, wall stress, and function in heart failure patients

Surgical ventricular restoration (SVR) was designed to treat patients with aneurysms or large akinetic walls and dilated ventricles. Yet, crucial aspects essential to the efficacy of this procedure like optimal shape and size of the left ventricle (LV) are still debatable. The objective of this study is to quantify the efficacy of SVR based on LV regional shape in terms of curvedness, wall stress, and ventricular systolic function. A total of 40 patients underwent magnetic resonance imaging (MRI) before and after SVR. Both short-axis and long-axis MRI were used to reconstruct end-diastolic and end-systolic three-dimensional LV geometry. The regional shape in terms of surface curvedness, wall thickness, and wall stress indexes were determined for the entire LV. The infarct, border, and remote zones were defined in terms of end-diastolic wall thickness. The LV global systolic function in terms of global ejection fraction, the ratio between stroke work (SW) and end-diastolic volume (SW/EDV), the maximal rate of change of pressure-normalized stress (dσ*/dt(max)), and the regional function in terms of surface area change were examined. The LV end-diastolic and end-systolic volumes were significantly reduced, and global systolic function was improved in ejection fraction, SW/EDV, and dσ*/dt(max). In addition, the end-diastolic and end-systolic stresses in all zones were reduced. Although there was a slight increase in regional curvedness and surface area change in each zone, the change was not significant. Also, while SVR reduced LV wall stress with increased global LV systolic function, regional LV shape and function did not significantly improve.

The evolving role of molecular imaging for coronary artery disease: where do we stand today?

The landscape of cardiac imaging is changing rapidly. There are promising new developments in molecular imaging on the horizon. It is likely that nuclear cardiology will continue to play an important role in the evaluation of CAD, but that role must evolve to meet clinical needs, competing technologies and the increasing emphasis on ensuring that imaging adds value and improves outcomes. This review offers some suggestions on the optimal role nuclear imaging can play vis-à-vis alternative options such as CT, but more data are needed before definitive recommendations can be made. Randomised trials comparing different diagnostic strategies can and should be performed to strengthen the foundations of clinical practice in nuclear cardiology. An evidence-based approach to imaging is here to stay.

Prevalence of significant extracoronary findings on multislice CT coronary angiography examinations and coronary artery calcium scoring examinations

The purpose of the study was to review the prevalence of significant extracoronary findings in patients who underwent multislice CT coronary angiography examinations and coronary artery calcium scoring examinations. We reviewed the reports of 295 consecutive patients who underwent multislice CT coronary angiography examinations and 140 consecutive patients who had separate coronary calcium scoring examinations from September 2004 to March 2006 in our department's radiology information system. Additional investigations carried out as a result of these findings were also recorded. Fifty-six (19%) out of 295 patients had significant extracoronary findings on coronary CT angiography requiring clinical or radiological follow up. There were 60 significant extracoronary findings. These included 24 patients who had pulmonary abnormalities, 4 who had mediastinal abnormalities, 20 who had upper abdominal abnormalities and 5 who had non-coronary cardiac abnormalities. Three patients had both pulmonary and upper abdominal abnormalities. Eleven (8%) out of 140 patients had significant pulmonary, breast, mediastinal, upper abdominal and cardiac abnormalities on coronary artery calcium scoring examinations, yielding a total of 12 significant findings. In our experience, 19% of the patients who underwent multislice CT coronary angiography and 8% of the patients who underwent coronary artery calcium scoring examinations had significant extracoronary findings requiring follow up. It is therefore imperative for the reporting physician to review the entire examination after the coronary arteries have been assessed. The prevalence of extracoronary findings on these examinations may be of significance, resulting in additional 'hidden costs' if widespread 'screening' is adopted.

Electrocardiographical case. Elderly man with acute breathlessness. Atrial tachycardia with variable AV conduction block and transient hyperkalaemia-induced aberrant conduction

A 67-year-old Chinese man presented to the emergency department with a history of abdominal bloating and shortness of breath. Initial electrocardiogram (ECG) showed atrial tachycardia (AT) with 2:1 atrioventricular (AV) conduction block. Six days after admission, he developed acute dyspnoea and confusion. Repeat ECG demonstrated a regular wide-complex tachycardia. Serum analysis revealed hyperkalaemia secondary to acute on chronic renal failure. Emergency treatment with intravenous calcium gluconate, 50% dextrose solution and short-acting insulin was instituted. The ECG promptly reverted to a narrow-complex AT with 2:1 AV conduction block. The diagnosis and treatment of AT are discussed.

Association analysis of endothelial nitric oxide synthase gene polymorphism with primary hypertension in a Singapore population

Vascular endothelial cells produce nitric oxide (NO), which contributes to the regulation of blood pressure and regional blood flow. Endothelial nitric oxide synthase (eNOS) gene polymorphisms are associated with coronary artery disease, but their linkage with primary hypertension is controversial. A total of 103 individuals with primary hypertension and 104 normotensive control subjects were studied in Singapore. The specific genotypes for G894T missense variant in exon 7, variable number tandem repeats (VNTR) in intron 4 (eNOS 4A/B/C) and T-786C in the promoter were isolated using allele-specific gene amplification and restriction fragment length polymorphism to examine the association of genotype and allelic frequency in both groups. Logistic regression analysis was also used to detect the association between genotypes and hypertension. Five genotypes of intron 4 VNTR (AA, AB, BB, AC and BC) were observed. Intron 4 B/B genotype was significantly associated with the hypertension group (P = 0.035), but disequilibrium of G894T and T-786C was absent between the two groups (P = 0.419 and P = 0.227), respectively. The overall distribution of allelic frequency differed significantly between the two groups, with four-repeat allele (4A) of intron 4 more frequent in the normotensive group than the hypertensive group (P = 0.019). Logistic regression analysis showed that intron 4 B/B genotype was significantly associated with systolic blood pressure of individuals with body mass index greater than 25 kg/m2 (P = 0.04). In conclusion, the eNOS 4 B/B genotype is a genetic susceptibility factor for primary hypertension in a Singapore population.

A case series of sotalol-induced torsade de pointes in patients with atrial fibrillation--a tale with a twist

INTRODUCTION

Sotalol is a potent antiarrhythmic often used in patients with atrial fibrillation. However, it has been associated with a risk of provoking other potentially dangerous arrhythmias, especially if used in high doses and in patients with uncorrected electrolyte imbalance or impaired renal and cardiac function.

CLINICAL PICTURE

We present 4 patients with atrial fibrillation treated with sotalol who developed torsade de pointes due to marked prolongation of the QT interval. While 1 patient had renal failure, all had normal left ventricular function. One patient had been treated with sotalol for more than 10 months before developing torsade de pointes precipitated by hypokalaemia, while another had tolerated sotalol for a 3-month period before the drug was discontinued, and only developed torsade de pointes when the drug was restarted 2 years later. Significantly, the doses used in all patients were relatively low, in contrast to most other reported cases where higher doses were used.

CONCLUSION

As with all antiarrhythmic therapy, these cases illustrate the need for close follow-up of patients treated with sotalol, even if relatively low doses are used. In addition, patients who had previously tolerated the drug well are still susceptible to its proarrhythmic effects.

Ethnic differences in acute myocardial infarction in Singapore

AIMS

We compare the myocardial infarction (MI) event and mortality rates among Chinese, Malay and Indian residents of Singapore.

METHODS

Residents, aged 20 to 64 years, with an MI event were identified from hospital discharge listings, postmortem reports, and the Registry of Births and Deaths. All pathology laboratories flagged patients with elevated creatine phosphokinase (CPK) levels. Modified MONICA (multinational monitoring of trends and determinants in cardiovascular disease) criteria were used for determining MI events.

RESULTS

From 1991 to 1999, 12 481 MI events were identified. Chinese patients were older and less likely to have typical symptoms or previous MI. Malays had the highest peak CPK level. Among all three ethnic groups, MI event and age-adjusted case-fatality rates declined. Compared with Chinese, MI event rates were >2-fold and >3-fold higher, and age-standardized coronary mortality rates were 2.4 and 3.0 higher times for Malays and Indians, respectively. Malays have the highest 3.1-year case-fatality, with an adjusted hazard ratio of 1.26 (95% confidence interval, 1.14 to 1.38) compared with Chinese.

CONCLUSION

We found strong ethnic differences in MI event, case-fatality and coronary mortality rates among the three ethnic groups in Singapore. While Indians have the greatest MI event rates, Malays have the highest case-fatality.

An outbreak of multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium, DT104L linked to dried anchovy in Singapore

Multidrug-resistant Salmonella enterica subsp. enterica serotype Typhimurium DT104L was first reported in Singapore from mid-July to mid-October 2000. Salmonella strains isolated from clinical laboratories were submitted to a reference laboratory for serotyping, phage-typing and pulsed-field gel electrophoresis (PFGE) using XbaI restriction endonuclease. An epidemiological investigation was conducted to determine the source of infection and mode of transmission using a structured questionnaire. A total of 33 cases involving mainly infants and toddlers were detected in the 3-month long outbreak. The outbreak strain was of the R-type ACGSTSu, i.e. resistant to ampicillin, chloramphenicol, gentamicin, streptomycin, tetracycline and sulphonamide. PFGE showed all isolates had an indistinguishable pattern, indicating a common source of infection. Consumption of imported dried anchovy was found to be the vehicle of transmission after adjusting for all confounding variables in the case-control study using stepwise logistic regression (OR 25.6; 95% CI 3.9-167.9; P = 0.001). Imported dried seafood should be properly processed, packed, labelled, and thoroughly cooked to prevent transmission of multidrug-resistant S. Typhimurium.

Leopard syndrome

The Leopard syndrome is a complex of multisystemic congenital abnormalities characterised by lentiginosis, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth and deafness (sensorineural). Hypertrophic cardiomyopathy, though not included in the mnemonic, is often associated. Although the Leopard syndrome is rare, it is important to recognise it since it can be associated with serious cardiac disease. It is advisable to follow up patients with Leopard syndrome for new onset of cardiac abnormalities and to monitor the progression of existing cardiac disease. We present a case report and review of the literature of this syndrome.

Giant coronary aneurysms with multiple vascular aneurysms: a rare manifestation of hyperhomocysteinemia

Hyperhomocysteinemia is associated with accelerated atherosclerosis, which leads to an increased incidence of premature vascular disease. Although multiple vascular aneurysms have been linked to hyperhomocysteinemia, coronary artery aneurysms have not. We report a case of giant coronary artery aneurysm associated with multiple peripheral vascular aneurysms in a patient with hyperhomocysteinemia.

Accuracy of the automated assessment of left ventricular function with gated perfusion SPECT in the presence of perfusion defects and left ventricular dysfunction: correlation with equilibrium radionuclide ventriculography and echocardiography

BACKGROUND

Gated single photon emission computed tomography (SPECT) with automated methods allows the quantitative assessment of left ventricular function and perfusion; however, its accuracy must be defined for patients with large earlier infarctions and severe rest perfusion defects, in whom the estimation of endocardial and epicardial borders might be more difficult, even with automated edge-detection techniques.

METHODS AND RESULTS

We prospectively compared the automated measurements of left ventricular ejection fraction (LVEF) and volumes from rest-injected gated Technetium 99m (Tc99m) perfusion SPECT with equilibrium radionuclide angiocardiography (ERNA) in 62 patients and the assessment of regional function with echocardiography in 22 patients. Forty-six patients had an earlier myocardial infarction (mean defect size, 34% of left ventricle; SD, 12.7%; range, 8% to 56%); 27 patients had large defects (> or = 20% of left ventricle; LVEF range, 8% to 75%). LVEF, as determined with Cedars-Sinai software (quantitative gated SPECT), correlated well with ERNA (r = 0.941; y = 1.003x + 1.15; P<.0001; SE of the estimate = 6.3%; mean difference -1.3% for LVEF) in the entire study population and in the subgroups of patients with an earlier infarction, severe defects, and large infarctions (> or = 20% of the left ventricle). A correlation existed between gated SPECT and ERNA volumes (r = 0.882, y = 1.040x - 14.7, P<.0001 for end-diastolic volume; r = 0.954, y = 1.147x - 13.9, P<.0001 for end-systolic volumes with the count-ratio technique), but with wider limits of agreement. The exact segmental score agreement between gated SPECT and echocardiography for regional function was 79.8% (281 of 352, kappa = 0.682).

CONCLUSIONS

Automated gated SPECT provides an accurate assessment of ejection fraction and regional function, even in the presence of an earlier myocardial infarction with large perfusion defects and significant left ventricular dysfunction.

Gated technetium-99m sestamibi for simultaneous assessment of stress myocardial perfusion, postexercise regional ventricular function and myocardial viability. Correlation with echocardiography and rest thallium-201 scintigraphy

OBJECTIVES

This study compares technetium-99m sestamibi (sestamibi) electrocardiographic (ECG) gated single-photon emission computed tomography (gated SPECT) and echocardiography for the evaluation of myocardial function and assesses the feasibility of single-injection, single-acquisition stress perfusion/rest function technetium-99m sestamibi-gated SPECT as an alternative to conventional stress/rest imaging for assessment of myocardial perfusion and viability.

BACKGROUND

Simultaneous assessment of stress perfusion and rest function is possible with gated SPECT acquisition of stress-injected technetium-99m sestamibi.

METHODS

Rest thallium-201 SPECT followed by stress sestamibi-gated SPECT (acquired 0.5 to 1 h after sestamibi injection) was performed in 58 patients. Echocardiography was performed immediately after or before gated SPECT in 43 of the patients. All studies were analyzed by semiquantitative visual scoring. Sestamibi-gated SPECT studies were read for stress perfusion and rest wall motion and thickening. Reversibility on sestamibi-gated SPECT was defined as the presence of a definite stress defect with normal or mildly impaired wall motion or thickening on gated SPECT:

RESULTS

There was high segmental score agreement between gated SPECT and echocardiography for wall motion (91%, kappa = 0.68, p < 0.001) and thickening (90%, kappa = 0.62, p < 0.001). Correlation for global wall motion (r = 0.98, p < 0.001) and thickening (r = 0.96, p < 0.001) scores between the two modalities was excellent. In 32 patients without previous myocardial infarction, there was excellent agreement for reversibility between stress sestamibi-gated SPECT and rest thallium-201/stress sestamibi (98%, kappa = 0.93, p < 0.01). However, in 26 patients with previous infarction, discordance between the two approaches was frequent, with 26% (20 of 78) of nonreversible defects by stress sestamibi-gated SPECT being reversible by rest thallium-201/stress sestamibi and 21% (23 of 112) of reversible defects by stress sestamibi-gated SPECT being nonreversible by rest thallium-201/stress sestamibi.

CONCLUSIONS

Gated SPECT of stress-injected sestamibi correlates well with echocardiographic assessment of regional function and thus adds information to perfusion SPECT: In patients without previous myocardial infarction, a single-injection stress perfusion/rest function approach using sestamibi-gated SPECT can substitute for conventional stress/rest myocardial perfusion imaging, adding a rest perfusion study only if there are nonreversible defects or consideration of attenuation artifacts. In patients with previous myocardial infarction, the gated SPECT approach does not replace the need for a rest perfusion study.