Pulmonary pressure-to-longitudinal strain ratio by echocardiography: a rapid surrogate to magnetic resonance for right ventricular failure assessment

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): United Christian Hospital Ruttonjee and Tang Siu Kin Hospitals

Background

Better risk stratification in pulmonary hypertension (PH) by echocardiography (echo) to detect ventricular vascular uncoupling may act as gate-keeper for downstream management, such as MRI and expensive therapies. Studies showed modest correlation found between RV peak global longitudinal strain (RVGLS), which is afterload dependent, and right ventricular ejection fraction (RVEF)

Purpose

To test the accuracy and optimal cut-off of echo derived mean PA pressure-to-RVGLS ratio against MRI detected severe RV dysfunction (defined as RVEF< 35%), RV dilatation (defined as RVEDVi >87ml), and correlate native T1-values (nT1)

Method

Strain analyses by echo and volumetric assessment by 1.5 tesla MRI were performed in all patients. Contoured MRI short axis images provided RVEF. In a subgroup of pulmonary arterial hypertension (PAH), right heart catheterization and MRI non-contrast native T1 mapping were performed (Figure 1). Using previous study data, to identify a difference of 1.8 pressure-to-strain ratio between mild and severe PH with a variance  of 2.2 , power of 80% and a significance level of 0.05, a total of 11 participants per group were needed

Result

Thirty-one PH patients (13 female, age 60 ± 14y, 13 had PAH) were recruited prospectively. Strong correlation was demonstrated between the mean PA pressure-to-RVGLS ratio to MRI derived RVEF (r = 0.80, p < 0.01), and to catheterization derived pulmonary vascular resistance and indexed cardiac output (r = -0.80, p= 0.001; r= -0.75, p = 0.003 respectively). The cut-off value of -2.5 had best accuracy in ROC analyses (Table 1)

In PAH patients, this ratio correlated with global nT1 at basal short-axis level (r= -0.91, p = 0.004), but not at the mid short-axis level. Their basal posterior interventricular insertion regions had significantly higher nT1 than those of age-matched normal controls at the same region on the same scanner (1256 ± 217 ms vs. 932 ± 25 ms, p = 0.04)

Conclusion

In terms of detection of severe right ventricular dysfunction by echocardiography, mean PA pressure-to-RVGLS ratio performed better than RVGLS alone, and a ratio cutoff of -2.5 predicts MRI determined ventricular vascular uncoupling in pulmonary hypertension

Table 1 Echo detect MRI AUC standard error 95% CI sens (%) spec (%) p Mean PA pressure -to-RVGLS ratio RVEF < 35% 0.86 0.073 0.71-1.00 72 83 0.007 RVEDVi > 87ml 0.81 0.081 0.65-0.97 83 70 0.004 RVGLS RVEF < 35% 0.76 0.100 0.57-0.96 60 83 0.048 RVEDVi > 87ml 0.73 0.090 0.55-0.91 67 70 0.032 PA pulmonary artery; RVGLS: RV global longitudinal strain; RVEDVi: indexed RV end-diastolic volume Abstract Figure 1

New Horizon on Community-Acquired Methicillin Resistant Staphylococcus Aureus (Ca-Mrsa) Skin and Soft Tissue Infection: Nanotechnology Antimicrobial Spray

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in community and hospital is increasing. The development of drug resistance may be attributed to the extensive use of antibiotics. Nanotechnology antimicrobial spray (NTAS), a physical antibacterial agent, is an alternative to antibiotic treatment on wound management. We report a case of MRSA associated skin abscess using NTAS in the wound management. NTAS possesses potent, broad spectrum antibacterial effect while carrying no risk of resistance and minimal adverse effect. Moreover, NTAS facilitates home wound management, thus reducing dependency on public health resources. Further studies are indicated to explore the clinical role of NTAS in an attempt to reduce the use of antibiotics. (Hong Kong j.emerg.med. 2011;18:432-436)

Continuous daily assessment of multiple sclerosis disability using remote step count monitoring

Disability measures in multiple sclerosis (MS) rely heavily on ambulatory function, and current metrics fail to capture potentially important variability in walking behavior. We sought to determine whether remote step count monitoring using a consumer-friendly accelerometer (Fitbit Flex) can enhance MS disability assessment. 99 adults with relapsing or progressive MS able to walk ≥2-min were prospectively recruited. At 4 weeks, study retention was 97% and median Fitbit use was 97% of days. Substudy validation resulted in high interclass correlations between Fitbit, ActiGraph and manual step count tally during a 2-minute walk test, and between Fitbit and ActiGraph (ICC = 0.76) during 7-day home monitoring. Over 4 weeks of continuous monitoring, daily steps were lower in progressive versus relapsing MS (mean difference 2546 steps, p < 0.01). Lower average daily step count was associated with greater disability on the Expanded Disability Status Scale (EDSS) (p < 0.001). Within each EDSS category, substantial variability in step count was apparent (i.e., EDSS = 6.0 range 1097-7152). Step count demonstrated moderate-strong correlations with other walking measures. Lower average daily step count is associated with greater MS disability and captures important variability in real-world walking activity otherwise masked by standard disability scales, including the EDSS. These results support remote step count monitoring as an exploratory outcome in MS trials.

Pulmonary complications of cystic fibrosis

The life expectancy of patients with cystic fibrosis (CF) has steadily increased over recent decades with a corresponding increase in the frequency of complications of the disease. Radiologists are increasingly involved with managing and identifying the pulmonary complications of CF. This article reviews the common manifestations of CF lung disease as well as updating radiologists with a number of less well-known complications of the condition. Early and accurate detection of the pulmonary effects of CF are increasingly important to prevent irreversible lung damage and give patients the greatest possibility of benefiting from the new therapies becoming available, which correct the underlying defect causing CF.

Estimating the heritability of reporting stressful life events captured by common genetic variants

BACKGROUND

Although usually thought of as external environmental stressors, a significant heritable component has been reported for measures of stressful life events (SLEs) in twin studies. Method We examined the variance in SLEs captured by common genetic variants from a genome-wide association study (GWAS) of 2578 individuals. Genome-wide complex trait analysis (GCTA) was used to estimate the phenotypic variance tagged by single nucleotide polymorphisms (SNPs). We also performed a GWAS on the number of SLEs, and looked at correlations between siblings.

RESULTS

A significant proportion of variance in SLEs was captured by SNPs (30%, p = 0.04). When events were divided into those considered to be dependent or independent, an equal amount of variance was explained for both. This 'heritability' was in part confounded by personality measures of neuroticism and psychoticism. A GWAS for the total number of SLEs revealed one SNP that reached genome-wide significance (p = 4 × 10-8), although this association was not replicated in separate samples. Using available sibling data for 744 individuals, we also found a significant positive correlation of R 2 = 0.08 in SLEs (p = 0.03).

CONCLUSIONS

These results provide independent validation from molecular data for the heritability of reporting environmental measures, and show that this heritability is in part due to both common variants and the confounding effect of personality.

Depressive disorder moderates the effect of the FTO gene on body mass index

There is evidence that obesity-related disorders are increased among people with depression. Variation in the FTO (fat mass and obesity associated) gene has been shown to contribute to common forms of human obesity. This study aimed to investigate the genetic influence of polymorphisms in FTO in relation to body mass index (BMI) in two independent samples of major depressive disorder (MDD) cases and controls. We analysed 88 polymorphisms in the FTO gene in a clinically ascertained sample of 2442 MDD cases and 809 controls (Radiant Study). In all, 8 of the top 10 single-nucleotide polymorphisms (SNPs) showing the strongest associations with BMI were followed-up in a population-based cohort (PsyCoLaus Study) consisting of 1292 depression cases and 1690 controls. Linear regression analyses of the FTO variants and BMI yielded 10 SNPs significantly associated with increased BMI in the depressive group but not the control group in the Radiant sample. The same pattern was found in the PsyCoLaus sample. We found a significant interaction between genotype and affected status in relation to BMI for seven SNPs in Radiant (P<0.0057), with PsyCoLaus giving supportive evidence for five SNPs (P-values between 0.03 and 0.06), which increased in significance when the data were combined in a meta-analysis. This is the first study investigating FTO and BMI within the context of MDD, and the results indicate that having a history of depression moderates the effect of FTO on BMI. This finding suggests that FTO is involved in the mechanism underlying the association between mood disorders and obesity.

The prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting: cross-sectional study

OBJECTIVES

To determine the prevalence of microalbuminuria among patients with type II diabetes mellitus in a primary care setting, and to study the association between various risk factors and the presence of microalbuminuria.

DESIGN

Cross-sectional community-based study.

SETTING

Four primary care clinics, Hong Kong.

PATIENTS

All patients with type II diabetes mellitus who regularly attended the clinics between May 2002 and March 2003.

MAIN OUTCOME MEASURES

Patients' demographic data, the proportion with microalbuminuria (measured using a spot urine test), and the association between this condition and risk factors for diabetic nephropathy (via correlation and multivariable logistic regression analysis).

RESULTS

The mean age of the 1161 patients in the sample population was 58.0 years. The mean duration of diabetes mellitus was 5.7 years, and the mean level of glycated haemoglobin was 7.4%. A total of 13.4% of the patients had microalbuminuria. Having the condition was significantly associated with advanced age, female sex, poor glycaemic control, and coexisting hypertension in both correlation and regression analyses. No significant association with ever smoking was found.

CONCLUSION

Early screening for incipient diabetic nephropathy and aggressive management of modifiable risk factors in a primary care setting may be important in optimising the renal outcome of patients with type II diabetes mellitus.

A study on SARS awareness and health-seeking behaviour - findings from a sampled population attending National Healthcare Group Polyclinics

INTRODUCTION

The study aimed to assess the effectiveness of massive SARS public education effort on SARS awareness and the conduct of those suspected of having SARS.

MATERIALS AND METHODS

Five hundred and ninety-three respondents attending the National Healthcare Group Polyclinics (NHGP) participated in the survey from 9 to 13 June 2003. Associations between awareness of SARS symptoms and (i) first action to be taken and (ii) mode of transportation used, if the respondent was suspected of having SARS, were analysed using Chi-square or Fisher's exact tests. Logistic regression was performed to adjust for relevant covariates.

RESULTS

The majority (92.7%) of the respondents were aware of SARS symptoms. Television (91.6%), newspaper (65.2%) and radio (30.4%) formed the top 3 sources of information on SARS. Slightly more than half (51.6%) of those who suspect themselves of having SARS would choose to visit their primary health care doctors, while 22.7% of the respondents would go to Tan Tock Seng Hospital (TTSH). If they suspected themselves to have SARS, most (84.9%) of the 578 respondents would react appropriately by taking the SARS ambulance or driving themselves to TTSH. However, 60 respondents would nonetheless take public transport to TTSH [by taxi 8.5%, mass rapid transit (MRT) or bus 1.9%]. In particular, the retired with lower educational levels were likely to be oblivious both to the symptoms of SARS and the possible consequences of travelling by inappropriate transport.

CONCLUSION

Despite more than 2 months of intensive SARS public education in Singapore, there remain important gaps in knowledge and appropriate behaviour that have to be bridged.

Fat intake in Hong Kong Chinese children

The people of Hong Kong are experiencing a transition in dietary practices and lifestyle that can be observed in the fat intakes of Hong Kong children as compared with those of their counterparts on mainland China. The studies described here include 1) a longitudinal and observational dietary survey beginning with a cohort of 174 newborns and concluding with 124 children at age 7 y; 2) a biochemical study of serum lipids in relation to dietary fat intake at age 7 y; 3) a chemical fatty acid analysis and comparison of duplicate meals collected from 20 Hong Kong and 20 mainland Chinese children at age 7 y; 4) a dietary assessment of 52 lactoovovegetarian children aged 4-14 y; and 5) a comparison of the growth of all subjects with US National Center for Health Statistics standards. About 30% of the total daily energy intake of Hong Kong Chinese children aged 1-7 y was contributed by fat-much more than that in the traditional Chinese diet. Growth of the children was not impaired, including that of children on the mainland and of those lactoovovegetarians in Hong Kong whose fat intakes were lower. Mean serum cholesterol of Hong Kong Chinese children at age 7 y was 4.59 mmol/L, significantly higher than that of their counterparts on the mainland, 4.16 mmol/L. Foods consumed in Hong Kong had a significantly lower ratio of 18:2 to 14:0. Nutritional deficiency was uncommon. Chinese children in Hong Kong had a dietary fat intake that was both quantitatively and qualitatively different from the traditional Chinese diet.

[Prevalence of obesity in Hong Kong children and adolescents aged 3-18 years]

A cross-sectional study on growth and development in Hong Kong children and adolescents ranging from their birth to 18 years of age was performed in 1993 and all the growth standards were constructed in the form of percentile chart. Those having a weight at one's median weight for height standard of 120% were defined as obesity. Prevalence of obesity in children and adolescents aged 3-18 was 10.08% (11.28% and 8.93% for boys and girls, respectively), which was higher than that in the inland of the country and that in Hong Kong as previously reported. Result showed there was a gradual increase in the prevalence after the age of 5, which reached a peak at the age of 11 for boys and 8 for girls.

Serum cholesterol and dietary fat of two populations of southern Chinese

Children in Hong Kong (HK) are the second generation of Chinese migrants from Guangdong Province and are leading a more affluent lifestyle than those in Jiangmen (JM). The association between affluence and coronary risk was investigated by comparing the serum cholesterol and dietary fat intake of children in HK and JM. Fasting serum cholesterol was examined in 94 HK children and 99 JM children, all aged seven, using the same enzymatic method by the same observer. Duplicate meals were collected in two subsamples of 20 children, one each from HK and JM and analysed for their total fat intake and fatty acid profile, again by the same observer using gravimetric methodology and gas chromatography. The mean (SD) cholesterol of HK children was 4.59 (0.83) mmol/l, significantly higher than that of JM, 4.16 (0.61) mmol/l. The daily fat intake by the HK children was 48 g, 37% higher than that of JM at 35 g. PS ratio was 0.6in HK and 0.8 in JM. Cl8-2/C14-0, the cholesterol-lowering ratio, was mostly below 10 in HK, whereas that of JM was between 10 and 40 Therefore, in order to lower the total serum cholesterol of Hong Kong children, dietary intervention to lessen total fat, in particular milk and animal fat, while moderately increasing fat consumption from vegetable sources would seem to be appropriate.

[A comparative study on blood cholesterol and dietary fat intake between Hong Kong and Cantonese children]

Blood cholesterol level in children aged 7 in Hong Kong (4.59mmol/L) was significantly higher than that in Jiangmen City, Guangdong Province (4.16mmol/L). Duplicate meals were collected from 20 children each in Hong Kong and Jiangmen for chemical analysis of fat intake and fatty acid profile. Results showed daily fat intake was 34.7 g for children in Jiangmen, which was about 30% lower than that in Hong Kong (47.6 g). Fatty acid profile in the diet of Jiangmen children showed a significantly higher polyunsaturated fatty acid saturated fatty acid ratio (0.81 vs 0.69) and linoleic acid/myristic acid ratio (20.73 vs 10.91) than that of Hong Kong children. It suggested dietary mode in a society with rapid developing economy and well-to-do life has changed, and it is necessary to prevent from the damage to health, especially the risk of coronary heart disease, caused by over-nutrition, as early as possible.

Bone mineral content of two populations of Chinese children with different calcium intakes

Bone mineral content (BMC) of 5-year-old Chinese children (115 children in Jiangmen, China and 128 children in Hong Kong) was evaluated by single-photon absorptiometry at the distal 1/3 radius. The mean (S.D.) calcium intakes of children of Jiangmen and Hong Kong were 244 (46) and 542 (332) mg/day, respectively. The mean BMC, weight and height of Jiangmen children were significantly less than Hong Kong children by 14%, 10% and 4%, respectively (P < 0.001). Multiple regression analysis showed that 62% of the variance in BMC was explained by bone width (BW), weight and regional location (P < 0.0001). A regional difference in BMC of 0.0303 g/cm (P < 0.0001) still remained after adjusting for BW and weight by multiple regression analysis. When comparing sub-groups of children in the two regions with comparable low current calcium intake at 5 years, the BMC of Jiangmen children was still significantly lower than Hong Kong children even when potential confounders were adjusted (P < 0.003). The study suggests that the regional discrepancy in BMC might be explained by long-term habitual calcium intake and physical activity.

Traumatic spinal cord injury in Hawaii

As a prelude to continuing surveillance in Hawaii, a 2-year retrospective study (1987-1989) was conducted by the Pacific Basin Rehabilitation Research & Training Center (PBRRTC) and the Rehabilitation Hospital of the Pacific (REHAB) in order to examine the frequency and causes of traumatic spinal cord injury (SCI) at REHAB; determine similarities and differences when compared to national statistics and make recommendations for future study. Data were abstracted from patient records at REHAB. During the period of study, 59 persons were treated for SCI. Similar to the national database, 85% were males and 70% were teenagers and young adults. Motor Vehicle Accidents (MVAs) contributed to 38% of the injuries followed by falls (28%), sports (19%) and violence (16%); however, etiology differed according to age. Sixty-two percent of the lesions were cervical. Almost 50% were neurologically complete. Sixty-six percent were in wheelchairs. Over 50% were independent in mobility and feeding and nearly 40% were independent in bathing and dressing. Eighty-eight percent returned to their homes. In general, the case at REHAB did not differ from the national database. Because reporting has not been mandatory, actual SCI incidence in Hawaii is most likely higher. Information derived from a mandatory reporting system would lead to identification of high risk groups, development and evaluation of prevention programs, identification of patients requiring early intervention and rehabilitation, and better planning of health care services.