Utility of solid phase extraction for colorimetric determination of lead in waters, vegetables, biological and soil samples

Zakia Al-Mallah,Alaa S. Amin 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

A highly sensitive, selective and rapid method for the determination of lead based on the reaction of lead(II) with 5-(4′-chlorophenylazo)-6-hydroxypyrimidine-2,4-dione (CPAHPD) and the solid phase extraction of the Pb(II)–CPAHPD complex with Amberlite XAD-2000 was developed, in the presence of pH 5.6 buffer solution and Triton X-114 medium. CPAHPD reacts with lead to form a violet complex with a molar ratio of 2:1 (CPAHPD to lead). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol (0.2 mL). In isopentyl alcohol medium, the molar absorptivity of the complex is 1.13 × 106 L mol−1 cm−1 at 647 nm. Beer’s law is obeyed in the range of 5.0–160 ng mL−1 in the measured solution. The relative standard deviation for 10 replicate samples of 50 ng mL−1 level is 1.26%. The detection and quantification limits reaches 1.5 and 4.7 ng mL−1 in the original samples. The presented procedure was successfully applied for determination of lead content in real samples such as vegetables, waters, biological and soil samples with satisfactory results.

Utilization of a triacetylcellulose membrane to immobilize 5-(2′,4′-dimethylphenylazo)-6-hydroxypyrimidine-2,4-dione for erbium determination in real samples

Zakia Al-Mallah,Alaa S. Amin 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.63 No.-

A membrane optode formed by physical inclusion of a chromophore 2-amino-6-(1,3-thiazol-2yldiazenyl)phenol (ATDP) into a plasticized cellulose triacetate (CTA) matrix was investigated for preconcentration, extraction and colorimetric determination of Er(III) from aqueous samples. The optode was examined for erbium uptake in borate buffer medium (∼125 ng mL−1) at pH 8.5–9.0. The inclusion of an anion-exchanger tri-isooctylamine (TiOA) was found to be necessary for the formation of Er(III)–ATDP complex in the optode matrix, resulting into distinct color change of the optode from red to violet color after erbium sorption. The composition of the optode was prepared by varying the amounts of different plasticizers and TiOA to obtain minimum response time towards Er(III) in borate buffer medium. The effects of different experimental parameters involved in the detection and quantification of Er(III) using optode were optimized. The optode analytical performance was performed in terms of interference of cations and anions, reusability, equilibration time, detection limit, etc. and compared with the conventional colorimetric method for Er(III) using different chromophores. The optode developed in the present study was tested in real samples with good results comparing to the GF-AAS method.

Prognostic value of age adjusted segment involvement score as measured by coronary computed tomography: a potential marker of vascular age

Ayoub, Chadi,Kritharides, Leonard,Yam, Yeung,Chen, Li,Hossain, Alomgir,Achenbach, Stephan,Al-Mallah, Mouaz H.,Andreini, Daniele,Berman, Daniel S.,Budoff, Matthew J.,Cademartiri, Filippo,Callister, Tra Springer-Verlag 2018 Heart and vessels Vol.33 No.11

Prognostic value of chronic total occlusions detected on coronary computed tomographic angiography

Opolski, Maksymilian P,Gransar, Heidi,Lu, Yao,Achenbach, Stephan,Al-Mallah, Mouaz H,Andreini, Daniele,Bax, Jeroen J,Berman, Daniel S,Budoff, Matthew J,Cademartiri, Filippo,Callister, Tracy Q,Chang, Hy BMJ Group 2019 Heart Vol.105 No.3

<P><B>Objective</B></P><P>Data describing clinical relevance of chronic total occlusion (CTO) identified by coronary CT angiography (CCTA) have not been reported to date. We investigated the prognosis of CTO on CCTA.</P><P><B>Methods</B></P><P>We identified 22 828 patients without prior known coronary artery disease (CAD), who were followed for a median of 26 months. Based on CCTA, coronary lesions were graded as normal (no atherosclerosis), non-obstructive (1%–49%), moderate-to-severe (50%–99%) or totally occluded (100%). All-cause mortality, and major adverse cardiac events defined as mortality, non-fatal myocardial infarction and late coronary revascularisation (≥90 days after CCTA) were assessed.</P><P><B>Results</B></P><P>The distribution of patients with normal coronaries, non-obstructive CAD, moderate-to-severe CAD and CTO was 10 034 (44%), 7965 (34.9%), 4598 (20.1%) and 231 (1%), respectively. The mortality rate per 1000 person-years of CTO patients was non-significantly different from patients with moderate-to-severe CAD (22.95; 95% CI 12.71 to 41.45 vs 14.46; 95% CI 12.34 to 16.94; p=0.163), and significantly higher than of those with normal coronaries and non-obstructive CAD (p<0.001 for both). Among 14 382 individuals with follow-up for the composite end point, patients with CTO had a higher rate of events than those with moderate-to-severe CAD (106.56; 95% CI 76.51 to 148.42 vs 65.45; 95% CI 58.01 to 73.84, p=0.009). This difference was primarily driven by an increase in late revascularisations in CTO patients (27 of 35 events). After multivariable adjustment, compared with individuals with normal coronaries, the presence of CTO conferred the highest risk for adverse cardiac events (14.54; 95% CI 9.11 to 23.20, p<0.001).</P><P><B>Conclusions</B></P><P>The detection of CTO on non-invasive CCTA is associated with increased rate of late revascularisation but similar 2-year mortality as compared with moderate-to-severe CAD.</P><P><B>Trial registration number</B></P><P> NCT01443637.</P>

Improved 5-year prediction of all-cause mortality by coronary CT angiography applying the CONFIRM score

Deseive, Simon,Shaw, Leslee J.,Min, James K.,Achenbach, Stephan,Andreini, Daniele,Al-Mallah, Mouaz H.,Berman, Daniel S.,Budoff, Matthew J.,Callister, Tracy Q.,Cademartiri, Filippo,Chang, Hyuk-Jae,Chin Oxford University Press 2017 European heart journal cardiovascular Imaging Vol.18 No.3

Maximization of the usage of coronary CTA derived plaque information using a machine learning based algorithm to improve risk stratification; insights from the CONFIRM registry

van Rosendael, Alexander R.,Maliakal, Gabriel,Kolli, Kranthi K.,Beecy, Ashley,Al’Aref, Subhi J.,Dwivedi, Aeshita,Singh, Gurpreet,Panday, Mohit,Kumar, Amit,Ma, Xiaoyue,Achenbach, Stephan,Al-Mallah, Mou Elsevier 2018 Journal of cardiovascular computed tomography Vol.12 No.3

<P><B>Abstract</B></P> <P><B>Introduction</B></P> <P>Machine learning (ML) is a field in computer science that demonstrated to effectively integrate clinical and imaging data for the creation of prognostic scores. The current study investigated whether a ML score, incorporating only the 16 segment coronary tree information derived from coronary computed tomography angiography (CCTA), provides enhanced risk stratification compared with current CCTA based risk scores.</P> <P><B>Methods</B></P> <P>From the multi-center CONFIRM registry, patients were included with complete CCTA risk score information and ≥3 year follow-up for myocardial infarction and death (primary endpoint). Patients with prior coronary artery disease were excluded. Conventional CCTA risk scores (conventional CCTA approach, segment involvement score, duke prognostic index, segment stenosis score, and the Leaman risk score) and a score created using ML were compared for the area under the receiver operating characteristic curve (AUC). Only 16 segment based coronary stenosis (0%, 1–24%, 25–49%, 50–69%, 70–99% and 100%) and composition (calcified, mixed and non-calcified plaque) were provided to the ML model. A boosted ensemble algorithm (extreme gradient boosting; XGBoost) was used and the entire data was randomly split into a training set (80%) and testing set (20%). First, tuned hyperparameters were used to generate a trained model from the training data set (80% of data). Second, the performance of this trained model was independently tested on the unseen test set (20% of data).</P> <P><B>Results</B></P> <P>In total, 8844 patients (mean age 58.0 ± 11.5 years, 57.7% male) were included. During a mean follow-up time of 4.6 ± 1.5 years, 609 events occurred (6.9%). No CAD was observed in 48.7% (3.5% event), non-obstructive CAD in 31.8% (6.8% event), and obstructive CAD in 19.5% (15.6% event). Discrimination of events as expressed by AUC was significantly better for the ML based approach (0.771) vs the other scores (ranging from 0.685 to 0.701), P < 0.001. Net reclassification improvement analysis showed that the improved risk stratification was the result of down-classification of risk among patients that did not experience events (non-events).</P> <P><B>Conclusion</B></P> <P>A risk score created by a ML based algorithm, that utilizes standard 16 coronary segment stenosis and composition information derived from detailed CCTA reading, has greater prognostic accuracy than current CCTA integrated risk scores. These findings indicate that a ML based algorithm can improve the integration of CCTA derived plaque information to improve risk stratification.</P>

Coronary revascularization vs. medical therapy following coronary-computed tomographic angiography in patients with low-, intermediate- and high-risk coronary artery disease: results from the CONFIRM long-term registry

Schulman-Marcus, Joshua,Lin, Fay Y.,Gransar, Heidi,Berman, Daniel,Callister, Tracy,DeLago, Augustin,Hadamitzky, Martin,Hausleiter, Joerg,Al-Mallah, Mouaz,Budoff, Matthew,Kaufmann, Philipp,Achenbach, S Oxford University Press 2017 European heart journal cardiovascular Imaging Vol.18 No.8

<P><B>Abstract</B></P><P><B>Aims</B></P><P>To identify the effect of early revascularization on 5-year survival in patients with CAD diagnosed by coronary-computed tomographic angiography (CCTA).</P><P><B>Methods and results</B></P><P>We examined 5544 stable patients with suspected CAD undergoing CCTA who were followed a median of 5.5 years in a large international registry. Patients were categorized as having low-, intermediate-, or high-risk CAD based on CCTA findings. Two treatment groups were defined: early revascularization within 90 days of CCTA (<I>n</I> = 1171) and medical therapy (<I>n</I> = 4373). To account for the non-randomized referral to revascularization, we developed a propensity score by logistic regression. This score was incorporated into Cox proportional hazard models to calculate the effect of revascularization on all-cause mortality. Death occurred in 363 (6.6%) patients and was more frequent in medical therapy. In multivariable models, when compared with medical therapy, the mortality benefit of revascularization varied significantly over time and by CAD risk (<I>P</I> for interaction 0.04). In high-risk CAD, revascularization was significantly associated with lower mortality at 1 year (hazard ratio [HR] 0.22, 95% confidence interval [CI] 0.11–0.47) and 5 years (HR 0.31, 95% CI 0.18–0.54). For intermediate-risk CAD, revascularization was associated with reduced mortality at 1 year (HR 0.45, 95% CI 0.22–0.93) but not 5 years (HR 0.63, 95% CI 0.33–1.20). For low-risk CAD, there was no survival benefit at either time point.</P><P><B>Conclusions</B></P><P>Early revascularization was associated with reduced 1-year mortality in intermediate- and high-risk CAD detected by CCTA, but this association only persisted for 5-year mortality in high-risk CAD.</P>

Incremental prognostic utility of coronary CT angiography for asymptomatic patients based upon extent and severity of coronary artery calcium: results from the COronary CT Angiography EvaluatioN For Clinical Outcomes InteRnational Multicenter (CONFIRM) S

Cho, Iksung,Chang, Hyuk-Jae,Ó,Hartaigh, Brí,ain,Shin, Sanghoon,Sung, Ji Min,Lin, Fay Y.,Achenbach, Stephan,Heo, Ran,Berman, Daniel S.,Budoff, Matthew J.,Callister, Tracy Q.,Al-Mallah, Moua The European Society of Cardiology 2015 European heart journal Vol.36 No.8

<P><B>Aim</B></P><P>Prior evidence observed no predictive utility of coronary CT angiography (CCTA) over the coronary artery calcium score (CACS) and the Framingham risk score (FRS), among asymptomatic individuals. Whether the prognostic value of CCTA differs for asymptomatic patients, when stratified by CACS severity, remains unknown.</P><P><B>Methods and results</B></P><P>From a 12-centre, 6-country observational registry, 3217 asymptomatic individuals without known coronary artery disease (CAD) underwent CACS and CCTA. Individuals were categorized by CACS as: 0–10, 11–100, 101–400, 401–1000, >1000. For CCTA analysis, the number of obstructive vessels—as defined by the per-patient presence of a ≥50% luminal stenosis—was used to grade the extent and severity of CAD. The incremental prognostic value of CCTA over and above FRS was measured by the likelihood ratio (LR) <I>χ</I><SUP>2</SUP>, <I>C</I>-statistic, and continuous net reclassification improvement (NRI) for prediction, discrimination, and reclassification of all-cause mortality and non-fatal myocardial infarction. During a median follow-up of 24 months (25th–75th percentile, 17–30 months), there were 58 composite end-points. The incremental value of CCTA over FRS was demonstrated in individuals with CACS >100 (LR<I>χ</I><SUP>2</SUP>, 25.34; increment in <I>C</I>-statistic, 0.24; NRI, 0.62, all <I>P</I> < 0.001), but not among those with CACS ≤100 (all <I>P</I> > 0.05). For subgroups with CACS >100, the utility of CCTA for predicting the study end-point was evident among individuals whose CACS ranged from 101 to 400; the observed predictive benefit attenuated with increasing CACS.</P><P><B>Conclusion</B></P><P>Coronary CT angiography provides incremental prognostic utility for prediction of mortality and non-fatal myocardial infarction for asymptomatic individuals with moderately high CACS, but not for lower or higher CACS.</P>

Incremental prognostic value of coronary computed tomography angiography over coronary calcium scoring for major adverse cardiac events in elderly asymptomatic individuals

Han, Donghee,Hartaigh, Brí,ain Ó,Gransar, Heidi,Lee, Ji Hyun,Rizvi, Asim,Baskaran, Lohendran,Schulman-Marcus, Joshua,Dunning, Allison,Achenbach, Stephan,Al-Mallah, Mouaz H,Berman, Daniel S Oxford University Press 2018 European heart journal cardiovascular Imaging Vol.19 No.6

<P><B>Abstract</B></P><P><B>Aims</B></P><P>Coronary computed tomography angiography (CCTA) and coronary artery calcium score (CACS) have prognostic value for coronary artery disease (CAD) events beyond traditional risk assessment. Age is a risk factor with very high weight and little is known regarding the incremental value of CCTA over CAC for predicting cardiac events in older adults.</P><P><B>Methods and results</B></P><P>Of 27 125 individuals undergoing CCTA, a total of 3145 asymptomatic adults were identified. This study sample was categorized according to tertiles of age (cut-off points: 52 and 62 years). CAD severity was classified as 0, 1–49, and ≥50% maximal stenosis in CCTA, and further categorized according to number of vessels ≥50% stenosis. The Framingham 10-year risk score (FRS) and CACS were employed as major covariates. Major adverse cardiovascular events (MACE) were defined as a composite of all-cause death or non-fatal MI. During a median follow-up of 26 months (interquartile range: 18–41 months), 59 (1.9%) MACE occurred. For patients in the top age tertile, CCTA improved discrimination beyond a model included FRS and CACS (C-statistic: 0.75 vs. 0.70, <I>P</I>-value = 0.015). Likewise, the addition of CCTA improved category-free net reclassification (cNRI) of MACE in patients within the highest age tertile (e.g. cNRI = 0.75; proportion of events/non-events reclassified were 50 and 25%, respectively; <I>P</I>-value <0.05, all). CCTA displayed no incremental benefit beyond FRS and CACS for prediction of MACE in the lower age tertiles.</P><P><B>Conclusion</B></P><P>CCTA provides added prognostic value beyond cardiac risk factors and CACS for the prediction of MACE in asymptomatic older adults.</P>

Prognostic implications of coronary artery calcium in the absence of coronary artery luminal narrowing

Cho, Iksung,ó,Hartaigh, Brí,ain,Gransar, Heidi,Valenti, Valentina,Lin, Fay Y.,Achenbach, Stephan,Berman, Daniel S.,Budoff, Matthew J.,Callister, Tracy Q.,Al-Mallah, Mouaz H.,Cademartiri, F Elsevier 2017 Atherosclerosis Vol.262 No.-

<P><B>Abstract</B></P> <P><B>Background and aims</B></P> <P>Coronary artery calcium (CAC) scoring is a predictor of future adverse clinical events, and a surrogate measure of overall coronary artery plaque burden. Coronary computed tomographic angiography (CCTA) is a contrast-enhanced method that allows for visualization of plaque as well as whether that plaque causes luminal narrowing. To date, the prognosis of individuals with CAC but without stenosis has not been reported. We explored the prevalence of CAC>0 and its prognostic utility for future mortality for patients without luminal narrowing by CCTA.</P> <P><B>Methods</B></P> <P>From 17 sites in 9 countries, we identified patients without known coronary artery disease, who underwent CAC scoring and CCTA, and were followed for >3 years. CCTA was graded for % stenosis according to a modified American Heart Association 16-segment model. We calculated hazard ratios (HR) with 95% confidence intervals (95% CI) for incident mortality and compared risk of death for patients as a function of presence or absence of CAC and presence or absence of luminal narrowing by CCTA.</P> <P><B>Results</B></P> <P>Among 6656 patients who underwent CCTA and CAC scoring, 399 patients (6.0%) had no coronary luminal narrowing but CAC>0. During a median follow-up of 5.1 years (IQR: 3.9–5.9 years), 456 deaths occurred. Compared to individuals without luminal narrowing or CAC, individuals without luminal narrowing but CAC>0 were older, more likely to be male and had higher rates of diabetes, hypertension, and dyslipidemia. Individuals without luminal narrowing but CAC experienced a 2-fold increased risk of mortality, with increasing risk of mortality with higher CAC score. Following adjustment, incident death persisted (HR, 1.8; 95% CI, 1.1–2.9, <I>p</I> = 0.02) among patients without luminal narrowing but with CAC>0 compared with patients whose CACS = 0. Individuals without luminal narrowing but CAC ≥100 had mortality risks similar to individuals with non-obstructive CAD (0 < stenosis<50%) by CCTA [HR 2.5 (95% CI 1.3–4.9) and 2.2 (95% CI 1.6–3.0), respectively].</P> <P><B>Conclusions</B></P> <P>Patients without luminal narrowing but with CAC experience greater risk of 5-year mortality. Patients with CAC score ≥100 and no coronary luminal narrowing experience death rates similar to those with non-obstructive CAD.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The prevalence of individuals without coronary stenosis but with evident coronary calcium was identified in this large international coronary CT angiography registry. </LI> <LI> Coronary plaques with positive remodeling reflect a potential mechanism for the presence of coronary calcium without luminal narrowing. </LI> <LI> The current study observed a worsened prognosis among those without luminal narrowing but with coronary artery calcium. </LI> </UL> </P>