Arka Chatterjee

A thermal study of the salts of azotetrazole

The four salts of 5,5′-azotetrazole (AzTz) selected for the present study were (1) disodium azotetrazole (Na2AzTz), (2) barium azotetrazole (BaAzTz), (3) lead azotetrazole (PbAzTz), and (4) mercury azotetrazole (HgAzTz). An attempt was made to correlate the thermal properties of these compounds with their explosive properties. Thermal behaviour was studied by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques under non-isothermal conditions. Compounds 1 and 2 showed endotherms at 120–140°C and 80–100°C, respectively, and exotherms at 265–315°C and180–220°C, respectively, whereas compounds 3 and 4 showed only exotherms at 180–210°C and 144–160°C, respectively. The weight losses observed in TG corresponding to the endotherms confirmed that they are due to removal of water of crystallisation. The enthalpies of dehydration and decomposition were calculated from experimental data. The kinetics of dehydration and decomposition were studied. The explosive sensitivity was determined by impact, friction and static charge tests. The thermal and explosive sensitivities increase in the order Na2AzTz

Transcatheter Pulmonary Valve Implantation: A Comprehensive Systematic Review and Meta‐Analyses of Observational Studies

Background Transcatheter pulmonary valve implantation is approved for the treatment of dysfunctional right ventricle to pulmonary artery conduits. However, the literature is limited because of a small patient population, and it does not reflect changing procedural practice patterns over the last decade. Methods and Results A comprehensive search of Medline and Scopus databases from inception through August 31, 2016 was conducted using predefined criteria. We included studies reporting transcatheter pulmonary valve implantation in at least 5 patients with a follow‐up duration of 6 months or more. In 19 eligible studies, 1044 patients underwent transcatheter pulmonary valve implantation with a pooled follow‐up of 2271 person‐years. Procedural success rate was 96.2% (95% confidence intervals [CI], 94.6–97.4) with a conduit rupture rate of 4.1% (95% CI, 2.5–6.8) and coronary complication rate of 1.3% (95% CI, 0.7–2.3). Incidence of reintervention was 4.4 per 100 person‐years overall (95% CI, 3.0–5.9) with a marked reduction in studies reporting ≥75% prestenting (2.9 per 100 person‐years [95% CI, 1.5–4.3] versus 6.5/100 person‐years [95% CI, 4.6–8.5]; P<0.01). Pooled endocarditis rate was 1.4 per 100 person‐years (95% CI, 0.9–2.0). Conclusions Our study provides favorable updated estimates of procedural and follow‐up outcomes after transcatheter pulmonary valve implantation. Widespread adoption of prestenting has improved longer‐term outcomes in these patients.

A study on thermal and explosive properties of hydrazotetrazoles

Abstract This paper discusses the results of the thermal decomposition studies on 5,5′-hydrazotetrazole (5,5′-HzTz) and its barium, lead and mercury salts. Dynamic differential scanning calorimetric and thermogravimetric techniques have been employed in this work. Decomposition temperature, heat of decomposition and Arrhenius rate parameters are reported. The decomposition data indicate that among the hydrazotetrazoles studied, PbHzTz is the least stable compound. Explosive properties such as impact, friction and electrostatic sensitivities as well as the initiating power of these compounds have been evaluated. These studies show that the lead compound is the most powerful primary explosive among the four compounds investigated. It appears that a correlation exists between the thermal decomposition data and the explosive characteristics of the above hydrazotetrazoles.

Thermal studies on tetrazole derivatives using a differential scanning calorimeter. I

Abstract The thermal decomposition of arylidene tetrazolyl hydrazones has been studied under dynamic and isothermal conditions using a differential scanning calorimeter. Attempts have been made to evaluate the thermochemical and kinetic parameters of these compounds. It has been observed that the thermal stability of the tetrazole derivatives decreases with increasing substitution of nitro groups in the aromatic ring.

Transdiaphragmatic Rupture of Hepatic Abscess Producing Purulent Pericarditis and Pericardial Tamponade

A 44-year-old homeless male presented to the emergency department with a 6-hour history of pleuritic chest pain, shortness of breath, and generalized weakness. He had an episode of acute cholecystitis 2 years prior, for which he received a cholecystostomy tube and intravenous antibiotics at another hospital. He had been scheduled in clinic for tube removal and elective cholecystectomy, but he had not shown up for his appointment. The tube had remained in place, and he continued to manually drain the cholecystostomy bag once a day for the past 2 years. On review of systems, we noted low-grade fever with night sweats, progressive abdominal distention, and intermittent abdominal discomfort. In the emergency department, he was tachycardic and hypotensive. Marked jugular venous distension, faint heart sounds, clear lungs, and a distended diffusely tender abdomen with a protruding cholecystostomy tube were noted on examination. The ECG showed sinus tachycardia and diffuse ST segment elevation and PR segment …

ELECTRON MICROSCOPE EXAMINATION OF POLYMER COATED HYDROPHILIC GUIDE WIRES USED FOR SIDE BRANCH PROTECTION DURING BIFURCATION CORONARY INTERVENTION

Polymer coated hydrophilic guidewires are routinely deployed for side-branch protection during bifurcation stenting. Isolated reports of polymer shearing raise concern for potential of these wires to cause embolic complications. We performed electron microscopic analysis of these wires in a series

Safety of hydrophilic guidewires used for side-branch protection during stenting and proximal optimization technique in coronary bifurcation lesions

BACKGROUND AND PROPOSE In coronary bifurcation lesions (CBL), hydrophilic guidewires used for side-branch (SB) protection can be withdrawn from underneath the stent easier than other wires. However, the safety of which has not been investigated. METHODS/MATERIALS We performed scanning electron microscopic (SEM) examination of hydrophilic wires - the Whisper and Runthrough wires - used for SB protection during stenting and proximal optimization technique (POT) in 30 patients with CBL. The distal 15cm of the wire was examined every 1mm by SEM and 4500 segments were analyzed to investigate for wire fracture, polymer shearing (PS), and its correlations with post-stenting creatine kinase (CK)-MB release. RESULTS SEM examination showed no evidence for wire fracture. The total area of PS and the largest defect on the wire were significantly larger with the Whisper wire versus the Runthrough wire (0.15±0.04mm2 vs. 0.026±0.01mm2 and 0.04±0.05mm2 vs. 0.01±0.01mm2; P<0.05, respectively). The total length of PS and the longest defect on the wire were significantly longer with the Whisper wire vs. the Runthrough wire (12.1±14.5mm vs. 2.7±3.0mm and 2.9±4.2mm vs. 1.0±1.2mm; P<0.05, respectively), but there were weak correlations between the extents of PS with CK-MB release. CONCLUSIONS Hydrophilic guidewires may be safely used for SB protection during stenting and POT in CBLs. The extent of PS was significantly greater with the Whisper wire than with the Runthrough wire, but its correlation with post-stenting CK-MB release was weak.

Left Atrial Mural Endocarditis Secondary to Mitral Valve Jet Lesion

A 38-year-old woman with Down syndrome and mitral valve prolapse presented with 2 weeks of fever and cough. She had presented to an outpatient clinic 1 week earlier and was prescribed empirical antibiotics for a suspected respiratory tract infection. Despite this therapy, she continued to have high spiking fevers and developed a fulminant rash, prompting emergent admission for further evaluation. She had previously been healthy without other risk factors for infective endocarditis. On admission to the intensive care unit, she was febrile, confused, tachycardic, and hypotensive. Examination showed peripheral signs of septic embolization, including Janeway lesions (Figure, A), splinter hemorrhages (Figure, B), Osler nodes (Figure, C), and conjunctival petechiae (Figure, D). An IV/VI plateau–shaped holosystolic murmur was heard in the mitral area with radiation to the axilla. Laboratory studies revealed neutrophilic leukocytosis and lactic acidosis. Transthoracic echocardiography showed myxomatous morphology of the mitral valve with holosystolic prolapse of the anterior mitral leaflet (Figure, E and Movie I in the online-only Data Supplement). Color-flow Doppler showed severe eccentric mitral regurgitation with a posteriorly directed regurgitant jet (Figure, F and Movie II in the online-only Data Supplement). Jet velocities in excess of 4 …

Patient preference: An important emerging factor in operator access site selection

Patient preference should emerge as a third component influencing radial versus femoral access for cardiac catheterization. Ideally dually experienced “switch‐operators” will consider co‐morbidities, technical procedural factors, and patient preferences to choose a tailored approach with each patient. A tailored and tempered three component approach to access selection which includes patient preferences will likely optimize patient‐centered outcomes.

Individualizing dual antiplatelet therapy duration: Prediction tools, genomics, and clinical judgment: Chatterjee and Hillegass

Prolonged dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) on average reduces the risk of subsequent myocardial infarction (MI) but increases major bleeds. Individualizing duration of DAPT based on the DAPT trials net benefit prediction tool would likely optimize outcome beyond population average recommendations. Individualizing agent selection and duration of therapy based on genomic data may further improve outcomes. Clinical judgment remains the most important tool to tailor DAPT duration based on a large array of additional relevant factors not captured by predition rules or genomics.