P900 The Heart Model: Automated LVEF calculation in the real world

Background

Heart Model (HM) is a proprietary, model-based algorithm for measurement of left ventricular ejection fraction (LVEF) in a 3D dataset acquired from an apical 4-chamber view by transthoracic echocardiography (TTE). There is evidence for superior reproducibility compared to 2D echo methods for LVEF measurement.

Objective

To assess the correlation of LVEF by HM with conventional, 2D LVEF methods.

Methods

All TTEs performed between 04-08/02/2019 by 2 HM-trained sonographers were included. Demographic characteristics, indication for TTE, LVEF by Simpson"s (LVEF_S), by "eyeballing" (LVEF_EB) and by HM (LVEF_HM), were recorded; LVEF for each study was also estimated by eye-balling by an experienced observer unaware of the reported LVEF (LVEF_IND). We compared LVEF by each method, their reciprocal correlations and their correlation with LVEF_HM. Image quality was rated excellent (endocardial border visible for all segments in the 3 apical views), good (< 1 segment was not visible / view), adequate (< 3 segments were not visible) and limited (<4 segments were not visible). Indications for TTE were: assessment of LVEF in 1/3 of the studies, murmurs in 1/5, and other indications in the rest.

Results

We included 74 patients (42 M, mean age (SD) 69.8(13.9), range 18-92 years). Forty-nine (66%) patients were in sinus rhythm, 23 (31%) were in AF, and the rest were in various paced rhythms. Fifty patients (68%) had excellent, good or adequate images. The EFs calculated by different methods are shown in the Table (p > 0.05 for all), an the Bland Altman plot (LVEF_EB vs HM) in the figure. LVEF_HM correlated modestly with the other methods if all studies were included (r = 0.535 LVEF_HM vs. LVEF_EB); the correlation improved if only good-quality studies were included (r = 0.769, p < 0.001 for both). All combinations of LVEF_IND, LVEF_EB and LVEF_S had correlation coefficients >0.93.

Conclusions

The Heart Model algorithm for LVEF measurement correlates well with traditional 2D methods in patients with good endocardial border definition, where its use can potentially improve reproducibility and reduce exam duration.

LVEF by method (good-quality studies) N = 50 Simpson"s Eyeballing HeartModel Independent Mean(%) 48.6 48.9 50.9 48.8 SD(%) 17.8 16.6 14.9 15.7 Median(%) 54.5 52.5 53 50 Range(%) 16-74 17.5-72.5 19-88 15-75 SD - standard deviation Independent - LVEF estimate (eyeballing) by independent observer unaware of reported EFs. LVEF_EB was chosen as it was available inall the reports.

Abstract P900 Figure. Bland Altman Plot (LVEF_EB vs LVEF_HM)

Effects of unidirectional flow shear stresses on the formation, fractal microstructure and rigidity of incipient whole blood clots and fibrin gels

Incipient clot formation in whole blood and fibrin gels was studied by the rheometric techniques of controlled stress parallel superposition (CSPS) and small amplitude oscillatory shear (SAOS). The effects of unidirectional shear stress on incipient clot microstructure, formation kinetics and elasticity are reported in terms of the fractal dimension (d_f) of the fibrin network, the gel network formation time (T_GP) and the shear elastic modulus, respectively. The results of this first haemorheological application of CSPS reveal the marked sensitivity of incipient clot microstructure to physiologically relevant levels of shear stress, these being an order of magnitude lower than have previously been studied by SAOS. CSPS tests revealed that exposure of forming clots to increasing levels of shear stress produces a corresponding elevation in d_f, consistent with the formation of tighter, more compact clot microstructures under unidirectional flow. A corresponding increase in shear elasticity was recorded. The scaling relationship established between shear elasticity and d_f for fibrin clots and whole blood confirms the fibrin network as the dominant microstructural component of the incipient clot in terms of its response to imposed stress. Supplementary studies of fibrin clot formation by rheometry and microscopy revealed the substantial additional network mass required to increase d_f and provide evidence to support the hypothesis that microstructural changes in blood clotted under unidirectional shear may be attributed to flow enhanced thrombin generation and activation. CSPS also identified a threshold value of unidirectional shear stress above which no incipient clot formation could be detected. CSPS was shown to be a valuable haemorheological tool for the study of the effects of physiological and pathological levels of shear on clot properties.

First detection and sequence analysis of thebla-CTX-M-15 gene in Lebanese isolates of extended-spectrum-β-lactamase-producingShigella sonnei

The emergence in Shigella species of extended-spectrum beta-lactamases (ESBL) that impart resistance to third-generation cephalosporins is a growing concern world-wide. So far, however, ESBL-producing Shigella have only been reported seven times, albeit from seven different countries. In Lebanon, three ESBL-producing clinical isolates of S. sonnei were recovered from 30 cases of shigellosis diagnosed between July 2004 and October 2005. All three were found to be resistant to amoxycillin, cefotaxime, ceftazidime, aztreonam, trimethoprim/sulphamethoxazole, gentamicin, and kanamycin. Each harboured the bla-CTX-M gene, and the results of sequence analysis indicated this to be of the bla-CTX-M-15 type and encoded on a 70-kb plasmid, flanked by an insertion element (ISEcp1). The bla-TEM-1 gene was also detected on the chromosomes of two of the ESBL-producing isolates. Class-2 integrons containing dhfr1, aadA1 and sat1 genes were detected on the chromosomes of all three isolates but not on the plasmids. Fluoroquinolone-modifying factors [QnrA, QnrB, QnrS or AAC(6')-Ib-cr] were not detected. The results of RAPD analysis, combined with data on antimicrobial susceptibility, indicated that each isolate was unique. In conclusion, the emergence of ESBL-producing isolates of S. sonnei has been demonstrated for the first time in Lebanon. The resistance of these isolates to third-generation cephalosporins was mediated by the CTX-M-15 enzyme, which was plasmid-encoded.

Dentistry a second time?

INTRODUCTION

Dentistry in Jordan is an attractive profession due to the high social standard it provides. This study aimed to investigate whether dentists would choose dentistry again and whether their professional expectations would change after years of practice. Of special interest were possible differences according to gender, age, degree and place of work.

METHODS

A self-completion questionnaire was filled by a stratified random sample of 355 dentists in Jordan using closed questions. The questionnaire included professional, social and economic factors that influenced people's choice of dentistry and whether they would choose it again and the reasons for that.

RESULTS

The results showed that 52% of dentists who returned the questionnaire had dentistry as their first choice; the most important determining factor was the dentist's grades in the general secondary education. Fifty-two per cent stated that they would not choose it for the second time, the main reason being the health problems acquired through the profession and the low income. Helping others and the social standard dentistry provides were the main reasons given for dentists to choose dentistry again.

CONCLUSION

We report that more than half of the dentists included in this study would not 'choose dentistry again' as their profession regardless of age, gender and degree. This is mainly due to health problems acquired and the low income. We found that job satisfaction is highly affected by the workplace, and that more females are dissatisfied by the profession. This suggests that cultural background strongly affects the career decision.

Stability and reproductive fitness of Schistosoma mansoni isolates with decreased sensitivity to praziquantel

These studies are focused on schistosomes derived from human infections not cured by three successive doses of praziquantel that also produced infections in mice that were significantly more difficult to cure than infections with control worms. Half (three of six) of these isolates retained their decreased response to praziquantel after multiple passages through the life-cycle in the absence of therapeutic pressure. Two of the isolates, including the one initially least sensitive to praziquantel; reverted, to a sensitivity not significantly different from controls. For example, the EE6 isolate initially required 680 mg/kg praziquantel to affect a 50% reduction in worm load in murine infections, but after only six passages through the life cycle over 5 years this was reduced to 113 mg/kg, not different from control infections. The stability of some of the isolates and the reversion of others indicates that the biological or genetic factors conferring decreased praziquantel response varies among the isolates. The three isolates that retained decreased sensitivity to praziquantel all showed compromises in reproductive fitness in the laboratory, expressed most frequently as a decreased cercarial production from snails infected with those isolates compared to controls. For example, the total cercarial production of snails infected with the EE10 isolate was only 57% that of controls. The reversion of some of the isolates to a praziquantel sensitive state and the decreased reproductive fitness of those that did not revert suggest that there is some biological cost associated with the relative praziquantel insensitivity of these worms, which could help limit the impact of such isolates in the field. Infections with the less sensitive isolates also produced significantly less circulating schistosomal antigen in mice, suggesting that a decrease in the host immune response elicited by these worms could be one of the factors contributing to the diminished praziquantel efficacy.

The carpal tunnel syndrome: diagnostic utility of the history and physical examination findings

STUDY OBJECTIVE

To assess the value of a history and physical examination findings in diagnosing the carpal tunnel syndrome, and to determine whether constellations of clinical findings identify patients at high or low risk for the carpal tunnel syndrome.

DESIGN

Comparison of diagnostic tests with neurophysiologic testing.

SETTING

Patients with upper extremity complaints of diverse causes referred to a neurophysiology laboratory for diagnostic studies.

METHODS

Before nerve conduction testing, a history, demographic and physical examination data, and a hand pain diagram were obtained from each patient. Diagrams were categorized as indicating the classic carpal tunnel syndrome, or as probable, possible, or unlikely to indicate the carpal tunnel syndrome. Associations between clinical data and nerve conduction results were examined in univariate and multivariate analyses.

RESULTS

Of 110 patients in the study, 44 (40%) had the carpal tunnel syndrome. Individually, the best predictors were hand pain diagram rating (positive predictive value, 0.59; 95% CI, 0.48 to 0.68) and Tinel sign (positive predictive value, 0.55, CI, 0.45 to 0.65). The combination of a positive Tinel sign and a probable or classic diagram rating had a positive predictive value of 0.71; CI, 0.53 to 0.85. Other findings from physical examination and the history were less useful. Just 9% of patients under 40 years of age with possible or unlikely diagram ratings had the carpal tunnel syndrome.

CONCLUSIONS

With the exceptions of age, Tinel sign, and hand pain diagram rating, findings from the physical examination and the history had limited diagnostic utility. Patients under 40 years of age with possible or unlikely diagram ratings were at low risk for the carpal tunnel syndrome. This finding, which should be confirmed in an independent population, suggests that subsets of patients may be managed without nerve conduction studies.

Comparison of blood levels of histamine and total ascorbic acid in pre-eclampsia with normal pregnancy

Levels of histamine and total ascorbic acid (L-ascorbic acid plus dehydroascorbic acid) in the peripheral blood of women in pre-eclampsia have been measured. The results show that blood histamine is increased both in the moderate and severe form of pre-eclampsia. Blood ascorbic acid on the other hand is increased only in the severe form of pre-eclampsia. The rise in histamine values may be in response to the rising blood pressure in pre-eclampsia. The rise in ascorbic acid values may reflect the reduced maternal blood volume and/or restricted transport of ascorbic acid from maternal to fetal tissues.

Hemostatic system changes induced by 50 micrograms and 30 micrograms estrogen/progestogen oral contraceptives. Modification of estrogen effects by levonorgestrel

Three oral contraceptive preparations were compared for effects on blood coagulation, fibrinolysis and platelet function in a total of 86 healthy young women. Two of the preparations contained 30 micrograms ethinyl estradiol combined with levonorgestrel or norethindrone acetate, and the third contained 50 micrograms mestranol and norethindrone. Tests were conducted before use of the agents, at intervals over 48 weeks' use and after discontinuation. This study showed that the changes in coagulation activity and fibrinolysis were largely related to the dose of estrogen in the contraceptive preparation; the smallest changes occurred with the low-dose (30 micrograms) preparations. This study also showed that changes occurring in certain coagulation factors and inhibitors were significantly smaller in the preparation containing 30 micrograms of ethinyl estradiol combined with levonorgestrel, suggesting that the progestogen used in these combination oral contraceptives modifies the estrogen effects.

The pediatric corner: the varied manifestations of Crohn's disease in children and adolescents

Thirty children less than 15 years of age with Crohn's disease are reported. The mean age of onset was nine years and five months. Delay in diagnosis may stem from the varying modes of presentation. The mean delay in diagnosis was two years. Chronic diarrhea and/or recurrent abdominal pain associated with extraintestinal manifestations, particularly abnormalities of growth and development suggests the possibility of Crohn's disease in the pediatric age group. Involvement of the terminal ileum occurred in 29 of the 30 patients. In addition, colonic disease occurred in 13 and jejunal involvement in one. Four patients presented with an acute onset of their disease. A favorable response to either medical or surgical therapy occurred in all four. Twenty-six patients had an insidious onset and tended to have a chronic course despite either medical and/or surgical therapy. Thirteen patients had an intestinal resection, with recurrence occurring in three from 1-4 years postoperatively. To date there has been one death.