Role of Asymptomatic COVID-19 Cases in Viral Transmission: Findings From a Hierarchical Community Contact Network Model

As part of ongoing efforts to contain the coronavirus disease (COVID-19) pandemic, understanding the role of asymptomatic patients in the transmission system is essential for infection control. However, the optimal approach to risk assessment and management of asymptomatic cases remains unclear. This study proposed a Susceptible, Exposed, Infectious, No symptoms, Hospitalized and reported, Recovered, Death (SEINRHD) epidemic propagation model. The model was constructed based on epidemiological characteristics of COVID-19 in China and accounting for the heterogeneity of social contact networks. The early community outbreaks in Wuhan were reconstructed and fitted with the actual data. We used this model to assess epidemic control measures for asymptomatic cases in three dimensions. The impact of asymptomatic cases on epidemic propagation was examined based on the effective reproduction number, abnormally high transmission events, and type and structure of transmission. Management of asymptomatic cases can help flatten the infection curve. Tracing 75% of the asymptomatic cases corresponds to a 32.5% overall reduction in new cases (compared with tracing no asymptomatic cases). Regardless of population-wide measures, household transmission is higher than other types of transmission, accounting for an estimated 50% of all cases. The magnitude of tracing of asymptomatic cases is more important than the timing; when all symptomatic patients were traced, tested, and isolated in a timely manner, the overall epidemic was not sensitive to the time of implementing the measures to trace asymptomatic patients. Disease control and prevention within families should be emphasized during an epidemic. Note to Practitioners-This article addresses the urgent need to assess the risk of another COVID-19 outbreak caused by asymptomatic cases and to find the optimal, most practical approach to asymptomatic case management. Previous studies mostly focused on the clinical and statistical characteristics of asymptomatic cases; few have evaluated the impact of asymptomatic case measures using mathematical modeling at the community scale. This study proposed a Susceptible, Exposed, Infectious, No symptoms, Hospitalized and reported, Recovered, Death (SEINRHD) propagation model based on local community structures and social contact networks, according to the development characteristics and trend of COVID-19 in a Chinese community. The conclusion provides theoretical support for emergency work of relevant departments in different periods of an epidemic. In the early stages of the epidemic, timely detection and isolation of symptomatic patients should be a priority. Where there are surplus resources for epidemic prevention, the authorities should consider increasing the proportion of asymptomatic patients being traced. Epidemic prevention measures among family members should be a primary focus of attention. This combination of strategies can help reduce the rate of viral transmission and result in extinguishing the epidemic.

Forecast and evaluation of asymptomatic COVID-19 patients spreading in China

In this paper, we propose a new SAIR model to depict the transmission dynamics of a novel coronavirus in China. We focus on the ability of asymptomatic COVID-19 patients to transmit and the potential impact of population movements on renewed outbreak transmission. Qualitative analysis of the model shows that when the basic productive number R 0 > 1 , the system will stabilize towards a unique endemic equilibrium and pass through a transcritical bifurcation around its disease-free equilibrium. Furthermore, by constructing an appropriate Lyapunov function, we prove that the disease-free equilibrium and endemic equilibrium are globally asymptotically stable under appropriate parameter conditions. Finally, some important results have been verified by numerical simulations.

Diagnostic performance of a novel digital immunoassay (RapidTesta SARS-CoV-2): A prospective observational study with nasopharyngeal samples

Introduction

Digital immunoassays are generally regarded as superior tests for the detection of infectious disease pathogens, but there have been insufficient data concerning SARS-CoV-2 immunoassays.

Methods

We prospectively evaluated a novel digital immunoassay (RapidTesta SARS-CoV-2). Two nasopharyngeal samples were simultaneously collected for antigen tests and Real-time RT-PCR.

Results

During the study period, 1127 nasopharyngeal samples (symptomatic patients: 802, asymptomatic patients: 325) were evaluated. For digital immunoassay antigen tests, the sensitivity was 78.3% (95% CI: 67.3%–87.1%) and the specificity was 97.6% (95% CI: 96.5%–98.5%). When technicians visually analyzed the antigen test results, the sensitivity was 71.6% (95% CI: 59.9%–81.5%) and the specificity was 99.2% (95% CI: 98.5%–99.7%). Among symptomatic patients, the sensitivity was 89.4% (95% CI; 76.9%–96.5%) with digital immunoassay antigen tests, and 85.1% (95% CI; 71.7%–93.8%) with visually analyzed the antigen test, respectively.

Conclusions

The sensitivity of digital immunoassay antigen tests was superior to that of visually analyzed antigen tests, but the rate of false-positive results increased with the introduction of a digital immunoassay device.

a potentially zoonotic infection isolated from symptomatic and asymptomatic patients in Iran: A systematic review and meta-analysis

PURPOSE

The present systematic review and meta-analysis was aimed to assess the weighted molecular prevalence of Blastocystis sp. in humans along with the comparative molecular prevalence and subtypes distribution of Blastocystis isolated from symptomatic and asymptomatic patients in Iran.

METHODS

International electronic databases including Medline/PubMed, ProQuest, Scopus, Embase, and Google Scholar were explored until 4th October 2020. Heterogeneity index was evaluated among studies using Cochran's Q test and I² index. Finally, 23 eligible studies were qualified to be included in this review.

RESULTS

The pooled molecular prevalence of Blastocystis sp. in Iran was reported 15.2% (95% CI 11.5-19.7). In addition, the molecular prevalence based on PCR-sequencing and STS primers was reported 12.5% (95% CI 8.6-17.7) and 19.8% (95% CI 13.1-28.8), respectively. Interestingly, there was a considerably higher prevalence among asymptomatic patients [25.1% (95% CI 20.8-30.0)] in comparison to symptomatic ones [21.0% (95% CI 15.9-27.2)]. In addition, the frequency of Blastocystis ST1, ST2, and ST3 from positive samples in symptomatic patients was 19.7%, 35.1%, and 47.4%, respectively. In addition, the prevalence of Blastocystis ST1, ST2, and ST3 from positive samples in asymptomatic patients was 27.1%, 26.8%, and 37.8%, respectively. The results obtained in Iran showed that Blastocystis is more common in asymptomatic patients compared to patients having clinical symptoms. Of note, ST3, as the most common subtype causing clinical symptoms, was the most prevalent reported subtype among both symptomatic and asymptomatic patients in the country.

CONCLUSIONS

Hence, the pathogenicity of the Blastocystis parasite is not subtype-specific and appears to be related to a variety of risk factors. Still the Blastocystis epidemiology is open to question and more large-scale studies should be performed on this aspect.

Clinical Features of COVID-19 Patients in Jordan: A Study of 508 Patients

BACKGROUND

The symptoms of COVID-19 have a wide range of severity ranging from no symptoms at all to mild symptoms, such as fever, cough, sore throat, general weakness. Moreover, in some situations, patients may develop severe complications as pneumonia, and sepsis, leading to death. This study aims to investigate the characteristic features of COVID-19 patients based on their medical condition prior to COVID-19 diagnosis.

METHODS

A retrospective cohort study took place between the 1st of April 2020 and the 31st of June 2020 in Prince Hamzah Hospital, Jordan. Patients were diagnosed by the Real-Time Reverse Transcriptase (RT)-PCR Diagnostic Panel, either through screening or for those who developed symptoms. During this period, patients who tested positive for COVID 19 were admitted to the hospital regardless of their symptoms according to the local government health policies. A total of 508 Patients were involved and divided into two groups based on the presence or absence of chronic illnesses prior to COVID-19 diagnosis.

RESULTS

A total of 371 patients were medically free (220 males and 151 females). Among them, 153 patients were symptomatic (41.2%), with an average hospitalization of 18 days. Generalized malaise, dry cough, and fever were the most common reported symptoms (51%, 45.8%, and 41.8%, respectively). On the other hand, the total number of COVID-19 patients with predefined comorbidities was 137 (93 males and 44 females). Among them, 86 patients (62.8%) were symptomatic, with an average duration of admission of 19.3 days. Similar to medically free patients, dry cough, generalized malaise, and fever were the most commonly reported symptoms (50%, 43%, and 38.4%, respectively). There was a statistically significant correlation between the presence of chronic illnesses and the development of symptoms among COVID-19 patients (P = 0.0001).

CONCLUSION

Dry cough, generalized malaise, and fever were the most commonly reported symptoms among our patients regardless of their medical condition. The average duration of hospitalization in medically free patients was less than patients with comorbidities, and it was less among asymptomatic compared to symptomatic patients. More than half of our COVID-19 patients were male and asymptomatic. A significant correlation between patients' medical condition and the possibility of developing symptoms in response to COVID-19 was identified.

Viral Replication and Antibody Kinetics in the Recognition of Asymptomatic COVID-19 Patients

Following the discovery of COVID-19 disease caused by the SARS-CoV-2 coronavirus, different studies have been carried out to recognize the stages of the disease and the methods of achieving correct diagnosis. Investigations of cases and their contacts have revealed different degrees in the symptomatology of the disease, with asymptomatic patients gaining relevance because of the controversy regarding their role in the spread of the disease. Recognition and assessment of asymptomatic patients is essential to carry out containment actions such as public health measures for affected patients and contacts. In this review, we assess the diagnostic aspects of asymptomatic patients according to the available evidence of people with COVID-19.

Classification of COVID-19 by Compressed Chest CT Image through Deep Learning on a Large Patients Cohort

Abstract

Corona Virus Disease (COVID-19) has spread globally quickly, and has resulted in a large number of causalities and medical resources insufficiency in many countries. Reverse-transcriptase polymerase chain reaction (RT-PCR) testing is adopted as biopsy tool for confirmation of virus infection. However, its accuracy is as low as 60-70%, which is inefficient to uncover the infected. In comparison, the chest CT has been considered as the prior choice in diagnosis and monitoring progress of COVID-19 infection. Although the COVID-19 diagnostic systems based on artificial intelligence have been developed for assisting doctors in diagnosis, the small sample size and the excessive time consumption limit their applications. To this end, this paper proposed a diagnosis prototype system for COVID-19 infection testing. The proposed deep learning model is trained and is tested on 2267 CT sequences from 1357 patients clinically confirmed with COVID-19 and 1235 CT sequences from non-infected people. The main highlights of the prototype system are: (1) no data augmentation is needed to accurately discriminate the COVID-19 from normal controls with the specificity of 0.92 and sensitivity of 0.93; (2) the raw DICOM image is not necessary in testing. Highly compressed image like Jpeg can be used to allow a quick diagnosis; and (3) it discriminates the virus infection within 6 seconds and thus allows an online test with light cost. We also applied our model on 48 asymptomatic patients diagnosed with COVID-19. We found that: (1) the positive rate of RT-PCR assay is 63.5% (687/1082). (2) 45.8% (22/48) of the RT-PCR assay is negative for asymptomatic patients, yet the accuracy of CT scans is 95.8%. The online detection system is available: http://212.64.70.65/covid.

Graphic Abstract

Challenge of post-COVID era: management of cardiovascular complications in asymptomatic carriers of SARS-CoV-2

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), a highly pathogenic member of family coronaviridae, has caused an exponentially growing global pandemic termed as the coronavirus disease 2019 (COVID-19) with more than 12 million cases worldwide till date. This deadly disease has average fatality rate of 6.5% and even higher among elderly patients and patients with comorbidities. SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE-2) as the entry receptor into host cell. ACE-2, a type-I transmembrane metallocarboxypeptidase, is a critical regulator of the renin-angiotensin system. The entry of SARS-CoV-2 within host cells results in a reduced availability of ACE-2 on the host cell surface followed by significant downregulation of ACE-2 gene expression. As ACE-2 is a well-known cardio-protective molecule, its downregulation could result in severe cardiac disorders. This review deals with a challenging aspect of SARS-CoV-2 infected patients who are asymptomatic or have mild syndromes similar to influenza infections. These patients are proving to be the Achilles’ heel to combat COVID-19 mainly in developing countries of South Asia, where the average number of tests conducted per million individuals is considerably low. Consequently, there is high possibility that individuals with negligible respiratory trouble will not be tested for SARS-CoV-2. Hence, a huge percentage of the population have the risk of developing cardiovascular disorders as a bystander effect of viral infection apart from being potential reservoir of disease transmission. Based on available demographic as well as molecular data, this review predicts a huge spike in cardiovascular disorders among this undetected reservoir in post COVID-19 era.

Universal admission screening strategy for COVID-19 highlighted the clinical importance of reporting SARS-CoV-2 viral loads

Previously limited to symptomatic patients, our hospital introduced a universal admission screening strategy for coronavirus disease 2019 on 25 April 2020. All patients were tested by RT-PCR. We observed decreased viral loads linked to increased screening of asymptomatic patients highlighting the fact that viral load values could guide infection control decisions.

Comparison of COVID-19 disease between young and elderly patients: Hidden viral shedding of COVID-19

Objectives

The symptoms of Coronavirus disease 2019 (COVID-19) vary among patients. The aim of this study was to investigate the clinical manifestation and disease duration in young versus elderly patients.

Methods

We retrospectively analyzed 187 patients (87 elderly and 100 young patients) with confirmed COVID-19. The clinical characteristics and chest computed tomography (CT) extent as defined by a score were compared between the two groups.

Results

The numbers of asymptomatic cases and severe cases were significantly higher in the elderly group (elderly group vs. young group; asymptomatic cases, 31 [35.6%] vs. 10 [10%], p < 0.0001; severe cases, 25 [28.7%] vs. 8 [8.0%], p = 0.0002). The proportion of asymptomatic patients and severe patients increased across the 10-year age groups. There was no significant difference in the total CT score and number of abnormal cases. A significant positive correlation between the disease duration and patient age was observed in asymptomatic patients (ρ = 0.4570, 95% CI 0.1198–0.6491, p = 0.0034).

Conclusions

Although the extent of lung involvement did not have a significant difference between the young and elderly patients, elderly patients were more likely to have severe clinical manifestations. Elderly patients were also more likely to be asymptomatic and a source of COVID-19 viral shedding.

The rate of SARS-CoV-2 positivity in asymptomatic pregnant women admitted to hospital for delivery: Experience of a pandemic center in Turkey

Objective

To investigate the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity in asymptomatic pregnant women admitted to hospital for delivery in a Turkish pandemic center.

Study Design

This prospective cohort study was conducted in Ankara City Hospital between April, 15, 2020 and June, 5, 2020. A total of 206 asymptomatic pregnant women (103 low-risk pregnant women without any defined risk factor and 103 high-risk pregnant women) were screened for SARS-CoV-2 positivity upon admission to hospital for delivery. Detection of SARS-CoV2 in nasopharyngeal and oropharyngeal samples was performed by Real Time Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) method targeting RdRp (RNA dependent RNA polymerase) gene. Two groups were compared in terms of demographic features, clinical characteristics and SARS-CoV-2 positivity.

Results

Three of the 206 pregnant women participating in the study had positive RT-PCR tests (1.4 %) and all positive cases were in the high-risk pregnancy group. Although, one case in the high-risk pregnancy group had developed symptoms highly suspicious for COVID-19, two repeated RT-PCR tests were negative. SARS-CoV-2 RT-PCR positivity rate was significantly higher in the high-risk pregnancy group (2.9 % vs 0%, p = 0.04).

Conclusion

Healthcare professionals should be cautious in the labor and delivery of high-risk pregnant women during the pandemic period and universal testing for COVID-19 may be considered in selected populations.

Comparison of serologic and molecular SARS-CoV 2 results in a large cohort in Southern Tuscany demonstrates a role for serologic testing to increase diagnostic sensitivity

Background

Since February 2020, Italian hospitals registered COVID-19 (COronaVIrus Disease 19) cases more often than the rest of the Europe. During this epidemic, health authorities requested swab tests, while seeking new patient paths.

Methods

A dual laboratory approach was evaluated, consisting of patient care reports for viral RNA detection on swabs and rapid serological tests in 516 patients (192 symptomatic or paucisymptomatic and 324 asymptomatic).

Results

We found the molecular positive fraction equal to 12% (23/192) among symptomatic/paucisymptomatic (S/P) and 15.4% (50/324) in asymptomatic (As) sets. Among subsets, we observed serologically positive results, corresponding to 35% (8/23) for S/P and 38% (19/50) for As. Among molecular negative cases, we detected specific Immunoglobulin G or M (Ig G or Ig M) positivity in the S/P cohort equal to 6.6% (11/167) and 6% (15/246) in As cases. For indeterminate molecular results, we found S/P serological positivity equal to 100% (1/1) and 54% (13/24) in As patients. We found higher (p < 0.05) seropositivity in older patients (n = 8) among symptomatic and positives for viral RNA (n.23).

Conclusions

It has been observed that a dual approach of serological and molecular tests detects a higher absolute number of disease cases in a pandemic context,which could improve monitoring and health surveillance efficacy. The age-related seropositivity frequency in this study, if confirmed, could enhance the validity of serological tests, especially in older patients.In these subjects, molecular positivity accompanied by serological positivity (distinct for M and G immunoglobulins) should help determine disease status and support decisions related to patient management.

18F-FDG PET/CT in asymptomatic patients with COVID-19: the submerged iceberg surfaces

OBJECTIVE

The aim of this case series is to describe our experience in diagnosis and management of oncological asymptomatic patients with COVID-19 who underwent ¹⁸F-FDG PET/CT.

METHODS

From March 9 to March 31, 2020, we identified 5 patients who had PET/CT findings suspicious for COVID-19, but no symptom of infection.

RESULTS

The first three patients were administered an SARS-CoV-2 test in a COVID-dedicated center, while the fourth and fifth were tested in our institution, in accordance with a new internal procedure. The SARS-CoV-2 test yielded positive results in all five patients.

CONCLUSION

In this COVID-19 emergency, our task as radiologists and nuclear medicine physicians is to be able to identify imaging findings suggestive of the disease and to manage patients without overloading the hospital system.

Viral dynamics in asymptomatic patients with COVID-19

Data are limited on the viral load, viral shedding patterns, and potential infectivity of asymptomatic patients (APs) with coronavirus disease 2019 (COVID-19). This study included 31 adult patients who were virologically confirmed to have COVID-19 but were asymptomatic on admission. Among these 31 patients, 22 presented symptoms after admission and were defined as asymptomatic patients in the incubation period (APIs); the other nine patients remained asymptomatic during hospitalization and were defined as asymptomatic patients (APs). The median cycle threshold (Ct) value of APs (39.0, interquartile range (IQR) 37.5-39.5) was significantly higher than that of APIs (34.5, IQR 32.2-37.0), indicating a lower viral load in APs. However, the duration of viral shedding remained similar in the two groups (7 days, IQR 5-14 days vs. 8 days, IQR 5-16 days). The study findings demonstrated that although APs with COVID-19 have a lower viral load, they still have certain period of viral shedding, which suggests the possibility of transmission during their asymptomatic period. Further longitudinal surveillance of these asymptomatic cases via virus nucleic acid testing are warranted.

Duration of asymptomatic status and outcomes following carotid endarterectomy and carotid artery stenting in the Carotid Revascularization Endarterectomy vs Stenting Trial

BACKGROUND

Most carotid revascularization studies define asymptomatic as symptom-free for more than 180 days; however, it is unknown if intervention carries similar risk among those currently asymptomatic but with previous symptoms (PS) vs those who were always asymptomatic (AA).

METHODS

We compared the periprocedural and 4-year risks of PS vs AA patients in the Carotid Revascularization Endarterectomy vs Stenting Trial (CREST) randomized to carotid endarterectomy (CEA) or carotid artery stenting (CAS)/angioplasty. Proportional hazards models adjusting for age, sex, and treatment were used to assess the risk of periprocedural stroke and/or death (S+D; any S+D during periprocedural period), stroke and death at 4 years (any S+D within the periprocedural period and ipsilateral stroke out to 4 years) and the primary end point at 4 years (any stroke, death, and myocardial infarction within the periprocedural period and ipsilateral stroke out to 4 years). Analysis was performed pooling the CEA-treated and CAS-treated patients, and separately for each treatment.

RESULTS

Of 1181 asymptomatic patients randomized in CREST, 1104 (93%) were AA and 77 (7%) were PS. There was no difference in risk when comparing the AA and PS cohorts in the pooled CAS+CEA population for periprocedural S+D (2.0% vs 1.3%), S+D at 4 years (3.6% vs 3.2%), or the primary end point (5.2% vs 5.8%). There were also no differences among those assigned to CEA (periprocedural S+D, 1.5% vs 0%; S+D at 4 years, 2.7% vs 0%; or primary end point, 5.1% vs 2.4%) or CAS (periprocedural S+D, 2.5% vs 2.8%; S+D at 4 years, 4.4% vs 6.9%; or primary end point, 5.3% vs 9.8%) when analyzed separately.

CONCLUSIONS

In CREST, only a small minority of asymptomatic patients had previous ipsilateral symptoms. The outcomes of periprocedural S+D, periprocedural S+D, and ipsilateral stroke up to 4 years, and the primary end point did not differ for AA patients compared with PS patients.

Coronary computed tomography angiography in the evaluation of intermediate risk asymptomatic individuals

Cardiovascular disease is still one of the main causes of death and an early identification of coronary artery disease (CAD) remains the primary step in clinical management of patients with cardiovascular risk factor. Coronary computed tomography angiography (CCTA) has shown high sensitivity in CAD detection and could be helpful as screening method. The purpose of this study was to assess the prevalence of coronary artery disease detected by CCTA in asymptomatic patients with an intermediate risk of CAD.

MATERIALS AND METHODS

We retrospectively selected 185 asymptomatic patients with an intermediate Framingan Risk Score (mean age was 62.3 ± 12.4 years); all patients underwent CCTA, using 640-slice CT.

RESULTS

Atherosclerotic plaques were present in 112 out of 185 patients (60.5%); 56 subjects (30.2%) had mild stenosis, 49 (26.5%) moderate stenosis, only 3 patients (1.6%) had severe stenosis and in 4 cases (2.2%) the "blooming effect" did not allow for evaluation of the degree of stenosis. Among the positive cases, a high number of patients (44.6%) [50] showed coronary artery disease in one vessel, 33 patients (29.4%) in two vessels, 22 patients (19.6%) in three vessels and 5 patients in four vessels or more (4.5%). Patients with moderate stenosis were older, had hypertension in most cases, higher total cholesterol levels and more often were smokers. The radiation dose (mSv) dispensed to the patients was 3.7 ± 1.6 mSv.

CONCLUSION

High prevalence of coronary stenosis detected by low-dose CCTA in patients not properly classified by the traditional methods of risk stratification commonly used in clinical practice emphasizes the need to extend the risk stratification to other diagnostic tools with higher capability to detect CAD.

Dobutamine Stress Echocardiography Unmasks Early Left Ventricular Dysfunction in Asymptomatic Patients with Uncomplicated Type 2 Diabetes: A Comprehensive Two-Dimensional Speckle-Tracking Imaging Study

BACKGROUND

Discrepancies are present in the literature on resting myocardial mechanics in patients with uncomplicated type 2 diabetes mellitus (T2DM). Data are noticeably sparse regarding circumferential function and torsional mechanics. Resting deformation imaging may not be sensitive enough to detect subtle dysfunctions. The aim of this study was thus to comprehensively evaluate myocardial mechanics in patients with T2DM at rest and to investigate whether dobutamine stress echocardiography could unmask functional alterations that would remain otherwise subtle at rest.

METHODS

Forty-four patients with T2DM and 35 healthy control subjects of similar age and sex were prospectively recruited. After conventional echocardiography, myocardial mechanics was evaluated at rest and during low-dose dobutamine stress echocardiography (target heart rate, 110 beats/min).

RESULTS

Patients with T2DM presented with altered global diastolic function but preserved systolic function. Deformation imaging indexes were similar between groups at rest, but significant differences were noticed under dobutamine infusion for longitudinal strain (-21.2 ± 2.4% vs -24.2 ± 2.5%, P < .001), circumferential strain (apex, -32.3 ± 5.3% vs -36.3 ± 5.3%, P = .002; papillary muscle, -25.6 ± 3.2% vs -28.0 ± 3.6%, P = .001; base, -23.2 ± 3.6% vs -25.3 ± 3.8%, P = .03), apical (11.2 ± 4.4° vs 14.1 ± 6.3°, P = .020) and basal (-12.2 ± 3.3° vs -14.3 ± 3.9°, P = .021) rotation, and twist (21.9 ± 5.9° vs 26.8 ± 8.3°, P = .007). Multivariate analysis identified epicardial fat, dyslipidemia, and fasting glycaemia as significant contributors to the changes from rest to dobutamine.

CONCLUSIONS

These findings demonstrate the usefulness of dobutamine stress echocardiography in establishing impairments in myocardial mechanics in patients with uncomplicated T2DM. Systemic metabolic disturbances and epicardial fat act as the main contributors to the blunted response to dobutamine stress in these patients.

Severe and Asymptomatic Aortic Stenosis Management Challenge: Knowing That We Do Not Really Know

OPINION STATEMENT

The clinical management of asymptomatic patients with severe aortic valve stenosis (AS) may be challenging. Indeed, there is substantial controversy over the optimal timing of intervention for these patients, as some advocate early intervention while others urge for a conservative management until symptom onset. In the meantime of randomized clinical trials aiming to compare both strategies of management, an integrative approach including several imaging modalities as well as biomarkers of the myocardial damage may help to improve the risk stratification of patients with asymptomatic severe AS and individualize strategy of treatment. The extent of aortic valve calcification, semi-quantitatively assessed by echocardiography but better fully quantitatively measured by computed tomography (CT), provides incremental value to predict rapid disease progression and adverse event and thus could be a potential trigger for early referral to intervention or guide the timing of clinical follow-up. In addition, the assessment of disease activity using positron emission tomography, combined with CT calcium scoring, may also help to better predict the disease progression. The comprehensive assessment of left ventricular (LV) function using speckle-tracking echocardiography and/or cardiac magnetic resonance may provide useful information regarding the actual repercussion of AS on the myocardium. Besides imaging modalities, the measurement of several circulating biomarkers associated with the extent of the myocardial damage may also improve the risk stratification of asymptomatic patients with severe AS and help guiding management. Finally, it should be emphasized that a personalized medicine, including this comprehensive integrative approach in heart valve clinics, should be advocated for the management of these challenging patients.

Left innominate vein stenosis in an asymptomatic population: a retrospective analysis of 212 cases

Background

Although left innominate vein (LIV) stenosis has been demonstrated to be attributed to compression by adjacent anatomical structures, most of the studies are focusing on hemodialysis patients with clinical symptoms compatible with LIV stenosis. The goal of this study was to retrospectively investigate the incidence of LIV stenosis and its influencing factors in an asymptomatic, non-hemodialysis population, which has rarely been performed.

Methods

From Jan 2013 to Dec 2014, 212 consecutive cases undergoing a chest multi-detector computed tomography (MDCT) angiography were enrolled. LIV stenosis was defined as loss of the area of the LIV (that is, 1 − compression degree) >25%. Multivariate logistic regression analysis was performed to explore the independent risk factors associated with LIV stenosis.

Results

LIV stenosis occurred in 35.4% of cases (75/212), with the median loss of the area of the LIV of 36.2% (interquartile range 30.2–49.8%). There were significant differences in age (62.5 ± 11.7 vs. 58.6 ± 14.3 years; P = 0.041), BMI (23.9 ± 2.9 vs. 23.0 ± 3.3, P = 0.036), the frequency of crossing site of LIV over the origin of the aortic arch (54.7 vs. 24.8%, P < 0.001), and the space between aortic arch and sternum [mean ± SD, 11.6 ± 4.2 mm vs. median, 14.1 (interquartile range 11.9–16.3) mm, P < 0.001] between patients with and without LIV stenosis, but only the latter two were confirmed as independent factors by the multivariate logistic regression analysis [crossing site of LIV over the aortic arch, OR (95% CI) = 2.632 (1.401, 4.944), P = 0.003; space between the aortic arch and sternum, OR (95% CI) = 0.841 (0.770, 0.919), P < 0.001].

Conclusion

The patients with an older age, high BMI, LIV crossing over the origin of the aortic arch, or smaller space between aortic arch and sternum may have high risks for LIV stenosis. They should be paid more attention to exclude LIV stenosis preoperatively using MDCT angiography to prevent venous access dysfunction and symptomatic development by fistula creation when hemodialysis is required.

Impact of sex and age on carotid plaque instability in asymptomatic patients-results from the Munich Vascular Biobank

BACKGROUND

It is still a controversial issue whether carotid endarterectomy (CEA) for asymptomatic carotid stenosis is superior to best medical treatment. The aim of this study was therefore to analyze the impact of sex and age on carotid plaque instability in asymptomatic patients undergoing CEA.

PATIENTS AND METHODS

Atherosclerotic plaques from 465 asymptomatic patients with high-grade carotid artery stenosis (2004 - 2013) at the Munich Vascular Biobank were analyzed. Ascertainment of lesion stability/instability was performed on formalin-fixed paraffin-embedded tissue samples using hematoxylin-eosin and elastic van Gieson staining. Unstable plaques were considered lesions with a fibrous cap < 200 µm overlaying lipid-rich atheroma.

RESULTS

The average age of the patients was 69.3 ± 8.2 years. Independent of age, asymptomatic men had in total more frequently unstable plaques in contrast to women (41 % versus 52%, p = 0.042). No differences were found in plaque instability between age-related quartiles (< 65, 65- 69, 70 - 74, > 74 years) for female sex (p = 0.422). In men, a continuous increase in plaque instability with age was observed, without achieving statistical significance (p = 0.125). The greatest differences between male and female sex were found in the last quartile (> 74 years), without achieving statistical significance (p = 0.053). The chance of unstable carotid plaques in men was significantly higher than in women (OR = 1.562, p = 0.040). The probability of age-associated quartiles related to the first quartile demonstrated significant increase in plaque instability in the group of 65- to 69-year-old patients (OR 1.867, p = 0.024) and for patients older than 74 years (OR 1.740, p = 0.040).

CONCLUSIONS

Asymptomatic men had in total more frequently unstable plaques in contrast to women. Thus, male sex seems to be an additional risk factor for ischemic stroke.

Opportunistic Screening of Vitamin B12 Deficiency in IT Professionals Presenting for Routine Health Check-up

INTRODUCTION

Vitamin B12 deficiency is mainly diagnosed in symptomatic patients. However, the deficiency may also be prevalent in asymptomatic patients. Our aim was to study the prevalence of Vit B12 deficiency in IT professionals (Information Technology Professionals from Software industry) who presented for routine health screening and to correlate the deficiency to various parameters.

MATERIALS AND METHODS

This was single centre, observational study comprising of 84 IT professionals. The data was collected in structured format. The study was designed to identify prevalence of Vit B12 deficiency and correlate to other factors such as type of diet, income level & regular use of medication (such as Antacid & Metformin).

RESULTS

Total 28 individuals were found to be deficient (33.34%). Prevalence of Vit B12 deficiency amongst Vegetarian and non vegetarian diet adhering subjects was 47.5% and 20.45% respectively. B12 deficiency was also prevalent in high income age group. Further chronic intake of PPI (Proton pump inhibitor) and Metformin was associated with prevalence of 37.5% and 33.34% in the present study.

CONCLUSION

During health screening of IT Professionals, significant prevalence of Vit B12 deficiency was noted across all income groups & non vegetarian diet consuming subjects also. There is significant correlation between Vit B12 deficiency with chronic use of PPI and Metformin.

Surgical Resection of Primary Tumor in Asymptomatic or Minimally Symptomatic Patients With Stage IV Colorectal Cancer: A Canadian Province Experience

BACKGROUND

Surgical resection of the primary tumor in patients with stage IV colorectal cancer (CRC) remains controversial. Survival benefit reported in the literature has been attributed to the selection of younger and healthier patients with good performance status. We have recently reported that resection of the primary tumor improved survival of patients with stage IV CRC. In this study we examined survival benefit of surgery in patients with asymptomatic or minimally symptomatic primary tumor.

PATIENTS AND METHODS

A cohort of patients with stage IV CRC and asymptomatic or minimally symptomatic primary tumor, who were diagnosed during the period of 1992 to 2005, in the province of Saskatchewan Canada, was evaluated. The Kaplan-Meier method was used to determine survival. A multivariate Cox proportional hazard regression analysis was performed to determine prognostic importance of resection of primary tumor. A test for interaction was performed for resection of primary tumor and other important clinicopathological variables.

RESULTS

A total of 834 patients with a median age of 70 years (range, 22-93) and male:female ratio of 58:42 were identified. Among them 521 (63%) patients underwent surgery and 361 (43.3%) received chemotherapy. Patients who underwent surgery and received any chemotherapy had a median overall survival of 19.7 months (95% confidence interval [CI], 16.9-22.6) compared with 8.4 months (95% CI, 6.9-10.0) if they did not have surgery (P < .0001). In multivariate analysis, 5-fluorouracil-based chemotherapy (hazard ratio [HR], 0.43; 95% CI, 0.36-0.53), surgical resection of the primary tumor (HR, 0.47; 95% CI, 0.39-0.57), metastasectomy (HR, 0.48; 95% CI, 0.38-0.62), and second-line chemotherapy (HR, 0.72; 95% CI, 0.58-0.92) were correlated with superior survival. A test for interaction between ≥ 1 metastatic sites and surgery was significant, which suggests a larger benefit of surgery in patients with stage IVA disease.

CONCLUSION

Results of this large population-based cohort study suggest that resection of the primary tumor in asymptomatic or minimally symptomatic patients with stage IV CRC improved survival independent of other prognostic variables. The benefit was more pronounced in stage IVA disease.

[The relevance of the ankle-arm index to the reclassification of cardiovascular risk in asymptomatic hypertensive middle-aged males]

BACKGROUND AND OBJECTIVE

The ankle-brachial index allows for the detection of subclinical cardiovascular disease and risk, by diagnosing peripheral arterial disease and arterial calcification. Asymptomatic hypertensive men, between 45-55 years and with the suspicion of low risk, could be an important population group to benefit from this technique. The aim of the study was to compare the frequency of abnormal ankle-brachial index (subclinical peripheral arterial disease and arterial calcification) between asymptomatic hypertensive and non-hypertensive men, of the same age and suspicion of low risk.

PATIENTS AND METHODS

Two hundred and forty-four asymptomatic men (122 hypertensive and 122 non-hypertensive), between 45 and 55 years and an REGICOR index<10, were voluntarily recruited using consecutive sampling. Complete anamnesis, physical examination, laboratory tests and ankle-brachial index determination were carried out on all patients.

RESULTS

We detected abnormal ankle-brachial index values in 9.8% (12 cases) of the hypertensive subjects and in 1.6% (2 cases) of non-hypertensive subjects (P=.006). In the multivariate analysis, hypertension was significantly associated with an abnormal ankle-brachial index (P<.026) (odds ratio [OR] 5.9, 95% confidence interval [95% CI] 1.2-28.3), smoking (P=.018) (OR 2.7; 95% CI 1.2-6.2) and abdominal obesity (P=.005) (OR 2.8; 95% CI 1.3-5.9).

CONCLUSIONS

The population group analyzed in this study might be considered as an overriding segment for detecting subclinical cardiovascular disease and risk with the ankle-brachial index. Further studies are needed to establish the prevalence of abnormal ankle-brachial index in this population in order to assess its efficiency.

Prevalence of asymptomatic ocular conditions in subjects with refractive-based symptoms

BACKGROUND

This study aims to determine the overall prevalence of ocular conditions in a population from 19 to 64 years old, presenting with refractive-based symptoms only. Results could impact clinical standard of eye care on a similar population.

METHODS

This is a retrospective study on patients seen for an eye examination at the Clinique Universitaire de la Vision (CUV), between January 2007 and 2009. Files of individuals who presented with refractive symptoms were only selected and classified by file number. Then, every third file from the beginning was kept and reviewed by a reader. A second reader did the same with every third file from the end. Both readers were trained to use the same analysis grid to classify the diagnosed ocular conditions. In the case of multiple findings, the most severe condition was considered. The overall prevalence of ocular conditions was determined by calculating their occurrence divided by the number of files analyzed.

RESULTS

A total of 860 charts were analyzed. In 26.1% of the cases an ocular condition was diagnosed. This work establishes a higher prevalence of ocular conditions compared to another study conducted in Canada in the past. This difference can be explained by a different analytical methodology and by the fact that all examinations, in this study, were made under pupillary dilation.

CONCLUSION

The presence of ocular conditions in 26% of asymptomatic patients supports the need to assess ocular health under pupil dilation as part of any eye examination. However, further cost-to-benefit analysis is required before establishing such a recommendation.

Biomarker discovery in serum from patients with carotid atherosclerosis

BACKGROUND

Blood-based biomarkers of atherosclerosis have been used to identify patients at high risk for developing stroke. We hypothesized that patients with carotid artery disease would have a distinctive proteomic signature in blood as compared to a healthy control population without carotid artery disease. In order to discover protein biomarkers associated with increased atherosclerotic risk, we used two different strategies to identify biomarkers from patients with clinically defined atherosclerosis who were undergoing endarterectomy for atherosclerotic carotid artery disease. These patients were compared with healthy matched controls.

METHODS

Serum was obtained from patients undergoing endarterectomy (EA; n = 38) and compared to a group of age-matched healthy controls (n = 40). Serum was fractionated using anion exchange chromatography and three different surface-enhanced laser desorption/ionization (SELDI) chip surfaces and then evaluated with mass spectrometry (MS) and two-dimensional difference gel electrophoresis (2D-DIGE).

RESULTS

A random forest (RF) analysis of the SELDI-MS protein peak data distinguished these two groups with 69.2% sensitivity and 73.2% specificity. Four unique SELDI peaks (4.2, 4.4, 16.7 and 28 kDa, all p< 0.01) showed the greatest influence in the RF model. The EA patients with a history of prior clinical atherosclerotic plaque rupture manifested as either stroke or transient ischemic attack (symptomatic; n = 16) were compared to patients with carotid atherosclerosis but no clinical evidence of plaque rupture (asymptomatic; n = 22). Analysis of the SELDI spectra did not separate these two patient subgroups. A subgroup analysis using 2D-DIGE images obtained from albumin-depleted serum comparing symptomatic (n = 10) to asymptomatic EA patients (n = 10) found 4 proteins that were differentially expressed (p < 0.01) in the symptomatic patients. These proteins were identified as α(1)-antitrypsin, haptoglobin and vitamin D binding protein that were downregulated and α(2)-glycoprotein precursor that was upregulated in the symptomatic EA group.

CONCLUSIONS

SELDI-MS data analysis of fractionated serum suggests that a distinct protein signature exists in patients with carotid atherosclerosis compared to age-matched healthy controls. Identification of 4 proteins in a subset of patients with symptomatic and asymptomatic carotid atherosclerosis suggests that these and other protein biomarkers may assist in identifying high-risk patients with carotid atherosclerosis.