Anticoagulation and bleeding events in Patients with Post- Operative Atrial Fibrillation After Cardiac Surgery

Background

Post-operative atrial fibrillation (POPAF) following cardiac surgery is a common arrhythmia associated with an increased morbidity and mortality. There is little data evaluating the safety and effectiveness of anticoagulation (AC) in POPAF patients. We investigated the occurrence of 30-days POP major bleeding or embolic events and their timing in relation to the index cardiac surgery, the initiation of the arrhythmia and of anticoagulation in patients who developed new onset POPAF.

Methods

4,073 consecutive patients undergoing cardiac surgery from September 2010- December 2016 were evaluated. Patients with history of AF/Aflutter were excluded. POPAF was confirmed by ECG or telemetry. Major post-operative bleeding that occurred after AF was defined using PLATO criteria or the BARC scale (any ≥3).

Results

3,230 patients were included (37% CABG, 69% valve surgery). The incidence of POAF was 24%. The median time (IQR) of POPAF was 3 (2) days after the index surgery. 64% of POAF patients were male and 14% had a history of stroke. The mean (SD) age was 72 (9) years old. The average (SD) CHA2DS2-VASc score was 3.9 (1.5). The initial postoperative AC was full dose heparin, lovenox or argatroban in 58% of patients. The rest of patients had low dose heparin/lovenox for DVT prophylaxis and/or were started on oral anticoagulation without a bridge. The median (IR) time of POPAF to anticoagulation was 1 (2) days. There were 15 (1.9%) major bleeding events; 88% of which occurred in patients receiving full anticoagulation. Major bleeding events occurred a median of 15 (9) days after the index surgery and 9 (6) days after anticoagulation. Independent predictors of major bleed were history of PAD (P<0.01) and pre-operative use of b-blockers (P=0.04). There were 11 (1.4%) POP strokes which occurred a median of 5 (16) days after the index surgery, and 2 (13) days after POPAF. 63% of strokes happened in patients that received anticoagulation. The mean CHA2DS2-VASc score were 3.9 (1.5) and 4.7 (1.7), P=0.1 for patients without and with strokes, respectively. Stroke history (P<0.01) was the only independent stroke predictor. Both strokes and bleeding events were associated with significantly longer ICU and hospital length of stay. 86% of POPAF patients received amiodarone during hospitalization and 2.1% electric cardioversion. Upon discharge, 2.3% of patients were in in atrial fibrillation and 0.8% in atrial flutter.

Conclusion

The post-operative course of major bleeds and stroke in patients with POPAF after cardiac surgery is different. Bleeding events are delayed and appear related to anticoagulation. The relative benefit of perioperative anticoagulation remains unclear.

Funding Acknowledgement

Type of funding sources: None.

Clinical and urodynamic outcomes in children with anorectal malformation subtype of recto-bladder neck fistula

INTRODUCTION

Patients with anorectal malformations (ARMs) have a high incidence of genitourinary anomalies. Those with a recto-bladder neck fistula may represent a high-risk group, but their long-term urologic outcomes are poorly described.

OBJECTIVE

To evaluate the clinical and urodynamic outcomes in a large cohort of patients with an ARM subtype of recto-bladder neck fistula.

MATERIALS AND METHODS

A retrospective cohort study was performed of patients who had been treated for a recto-bladder neck fistula at the present institution since 2007. The primary outcomes were the ability to achieve urinary continence after 4 years of age, and development of a mildly decreased glomerular filtration rate (GFR) or worse (<89 ml/min/1.73 m²). Continence was defined as the ability to store urine for 3-4 h during the day and 8 h overnight without leakage.

RESULTS

Demographic and clinical data are provided in the Summary Table. The most recent urodynamic findings included the presence of detrusor overactivity in 30 (75%) patients, median leak point pressure of 56.0 cmH₂O (range, 14-140), median functional cystometric capacity at 40 cmH₂O of 125.5% age-expected capacity (range, 36-473%), and median maximum cystometric capacity of 131.0% age-expected capacity (range, 44-473%). A mildly decreased GFR or worse developed in 13 (24%) patients. Of the 52 (78%) patients who were followed by pediatric urology at the present institution with a median follow-up of 30.9 months (range, 0.0-86.8), 35 (67%) were at least 4 years of age and could be assessed for continence. Continence was achieved in five (14%) patients voiding spontaneously and 15 (43%) performing CIC. Recurrent urinary tract infections (UTI) (OR 0.70, P = 0.006) were an independent predictor of incontinence, while urethral anomalies (OR 1.40, P = 0.03) were an independent predictor of chronic kidney disease (CKD) on multiple logistic regression analysis.

DISCUSSION

The findings favorably compared with other studies, but were more robust due to the size of the cohort and breadth of urologic evaluation. Limitations included the retrospective design at a single institution. Incomplete clinical data and misclassification of continence may have lead to bias.

CONCLUSIONS

This large cohort of patients with an ARM subtype of recto-bladder neck fistula had a high incidence of genitourinary anomalies. They were rarely able to achieve continence with spontaneous voiding alone and were at risk of developing CKD, both of which were likely multifocal in origin. Long-term urologic follow-up is warranted for patients with a recto-bladder neck fistula.

Optimal formation of genetically modified and functional pancreatic islet spheroids by using hanging-drop strategy

BACKGROUND

Rejection and hypoxia are important factors causing islet loss at an early stage after pancreatic islet transplantation. Recently, islets have been dissociated into single cells for reaggregation into so-called islet spheroids. Herein, we used a hanging-drop strategy to form islet spheroids to achieve functional equivalence to intact islets.

METHODS

To obtain single islet cells, we dissociated islets with trypsin-EDTA digestion for 10 minutes. To obtain spheroids, we dropped various numbers of single cells (125, 250, or 500 cells/30 μL drop) onto a Petri dish, that was inverted for incubation in humidified air containing 5% CO(2) at 37 °C for 7 days. The aggregated spheroids in the droplets were harvested for further culture.

RESULTS

The size of the aggregated islet spheroids depended on the number of single cells (125-500 cells/30 μL droplet). Their morphology was similar to that of intact islets without any cellular damage. When treated with various concentrations of glucose to evaluate responsiveness, their glucose-mediated stimulation index value was similar to that of intact islets, an observation that was attributed to strong cell-to-cell interactions in islet spheroids. However, islet spheroids aggregated in general culture dishes showed abnormal glucose responsiveness owing to weak cell-to-cell interactions. Cell-to-cell interactions in islet spheroids were confirmed with an anti-connexin-36 monoclonal antibody. Finally, nonviral poly(ethylene imine)-mediated interleukin-10 cytokine gene delivered beforehand into dissociated single cells before formation of islet spheroids increased the gene transfection efficacy and interleukin-10 secretion from islet spheroids >4-fold compared with intact islets.

CONCLUSION

These results demonstrated the potential application of genetically modified, functional islet spheroids with of controlled size and morphology using an hanging-drop technique.

Biostability and disinfectant by-product formation in drinking water blended with UF-treated filter backwash water

The overall objective of this study was to investigate the impact of blending membrane-treated water treatment plant (WTP) residuals with plant-filtered water on finished water quality in terms of biostability and disinfectant by-product (DBP) formation. Filter backwash water (FBWW) was treated with a pilot-scale ultrafiltration (UF) membrane to produce permeate that was blended with plant-finished water. The batch studies involved storing samples for a specified time with a disinfectant residual to simulate residence time in the distribution system. Both chlorinated and non-chlorinated FBWW streams were evaluated, and the experimental design incorporated free chlorine, monochloramine, and chlorine dioxide in parallel to a model system that did not receive a disinfectant dose. The results of the study found that blending 10% UF-treated FBWW with plant-filtered water did not have an impact on water biostability as monitored with heterotrophic plate counts (HPCs) or DBP concentrations as monitored by TTHM and HAA5 concentrations. However, the presence of preformed THM and HAA species found in chlorinated FBWW streams may result in higher levels of initial DBP concentrations in blended water matrices, and could have a significant impact on finished water quality in terms of meeting specific DBP guidelines or regulations.

Use of fungi for the bioconversion of rice straw into cellulase enzyme

Cellulase production was carried out by solid state bioconversion (SSB) method using rice straw, a lignocellulosic material and agricultural waste, as the substrate of three Trichoderma spp. and Phanerochaete chrysosporium in lab-scale experiments. The results were compared to select the best fungi among them for the production of cellulase. Phanerochaete chrysosporium was found to be the best among these species of fungi, which produced the highest cellulase enzyme of 1.43 IU/mL of filter paper activity (FPase) and 2.40 IU/mL of carboxymethylcellulose activity (CMCase). The "glucosamine" and "reducing sugar" parameters were observed to evaluate the growth and substrate utilization in the experiments. In the case of Phanerochaete Chrysosporium, the highest glucosamine concentration was 1.60 g/L and a high concentration of the release of reducing sugar was measured as 2.58 g/L obtained on the 4th day of fermentation. The pH values were also recorded. The range of the pH was about 5.15 to 5.56 in the case of Phanerochaete Chrysosporium.

Plasma levels of neuroexcitatory amino acids in patients with migraine or tension headache

Plasma amino acids were analysed in patients with migraine with (9) and without (80) aura, in patients with tension headache (14) and in controls (62). The neuroexcitatory amino acids glutamic acid, glutamine, glycine, cysteic acid and homocysteic acid were elevated in migraine patients while total thiols (cysteine/cystine) were reduced. Patients with tension headache had values which were similar to those of controls. Tryptophan was elevated in migraine patients without aura only. Studies on two patients showed that the raised resting excitatory amino acid levels became still further elevated during a migraine attack. These results show that high concentrations of neurotransmitter amino acids occur normally in migraine patients and suggest that this profile may be a contributory factor in migraine attacks. Tension headache, however, has different biochemical parameters.

Aspergillus fungal mass detected by transesophageal echocardiography

Cardiac fungal infections have become more prevalent and are being diagnosed with increasing frequency. The most common infective organism is Candida albicans, followed by Aspergillus fumigatus and Cryptococcus. Cardiac involvement is usually associated with endocarditis, myocarditis, pericarditis, or intracardiac fungal mass. Early diagnosis is imperative, as these patients have poor outcome once there is cardiac involvement. In this report we describe a patient in whom an intracardiac mass was detected with transesophageal echocardiography and confirmed to be aspergillus fungal ball at surgery.

Platelet sulphotransferase activity, plasma sulphate levels and sulphation capacity in patients with migraine and tension headache

Activity of both the M- and P-forms of sulphotransferase (ST) was measured in platelets from patients with migraine, tension headache and controls. Mean PST values were 0.065 +/- 0.023 and 0.057 +/- 0.052 nmol/mg protein/min for migraine patients with and without aura. The corresponding values for tension headache and controls were 0.122 +/- 0.059 and 0.127 +/- 0.093 nmol/mg protein/min respectively (p < 0.05). Mean MST values were not different for any of the groups, and MST and PST activities measured in two patients during a migraine attack were not significantly altered from baseline levels. Mean plasma inorganic sulphate concentrations and paracetamol metabolites were not significantly different in any of the groups studied. The results suggest that PST activity may be a factor in the aetiology of migraine.

IgG anticardiolipin antibody titer > 40 GPL and the risk of subsequent thrombo-occlusive events and death. A prospective cohort study

BACKGROUND

Anticardiolipin antibodies (aCL) have been associated with an increased risk of stroke and thrombo-occlusive events. Little is known about the influence of aCL on recurrent thrombo-occlusive events.

METHODS

Consecutively identified patients (n = 132) with focal cerebral ischemia [stroke = 112, transient ischemic attack (TIA) = 20] harboring aCL of at least 10 GPL units at the time of their index event were prospectively followed to estimate the effect of aCL titer on time to and risk of subsequent thrombo-occlusive events (stroke, TIA, deep venous thrombosis, pulmonary embolism, myocardial infarction) and death. On the basis of prior literature, we divided patients into those with aCL < or = 40 GPL (n = 111; mean age, 63 +/- 14 years; mean follow-up, 1.95 years) and those with aCL > 40 GPL (n = 21; mean age, 54 +/- 20 years; mean follow-up, 1.50 years).

RESULTS

There was no difference between groups for prevalence of hypertension, diabetes mellitus, cigarette smoking, atrial fibrillation, prior TIA, or sex. The GPL > 40 group was younger (54 +/- 20 versus 63 +/- 14 years; P = .055), had more prior strokes [9/21 (48%) versus 27/111 (20%); P = .030], more frequent subsequent thrombo-occlusive events and death [15/21 (71%) versus 51/111 (48%); P = .030], and a shorter median time (years) to event (0.15 versus 0.61, log rank P = .005). The risk ratio for recurrent event and death with GPL > 40 obtained from Cox proportional hazards models, adjusted for prior strokes, prior TIAs, hypertension, diabetes mellitus, atrial fibrillation, and cigarette smoking was 1.9 (95% confidence interval, 1.0 to 3.5; P = .051).

CONCLUSIONS

Our data suggest that subsequent thrombo-occlusive events and death after focal cerebral ischemia associated with IgG aCL may occur sooner and more frequently with GPL > 40.

Bioreductive activation of catechol estrogen-ortho-quinones: aromatization of the B ring in 4-hydroxyequilenin markedly alters quinoid formation and reactivity

There is a clear association between excessive exposure to estrogens and the development of cancer in several tissues including breast and endometrium. The risk factors for women developing these cancers are all associated with longer estrogen exposure, as may be facilitated by early menses, late menopause and long-term estrogen replacement therapy. Equilenin (1,3,5(10),6,8-estrapentaen-3-ol-17-one) or its 17-hydroxylated analogs make up 15% of the most widely prescribed estrogen replacement formulation, Premarin, and yet there is very little information on the human metabolism of these estrogens. In this study, we synthesized the catechol metabolite of equilenin, 4-hydroxyequilenin, and examined how aromatization of the B ring affects the formation and reactivity of the o-quinone (3,5-cyclohexadien-1,2-dione). 4-Hydroxyequilenin-o-quinone is much more redox-active and longer-lived than the endogenous catechol estrone-o-quinones, which suggests that the mechanism(s) of toxicity of the former could be quite different. Interestingly, the rate of reduction of the 4-hydroxyequilenin-o-quinone is increased at least 13-fold in the presence of NAD(P)H:quinone oxidoreductase (DT-diaphorase). Once NADH is consumed however, the catechol auto-oxidized rapidly to the o-quinone. NADH consumption was accompanied by dicumarol-sensitive oxygen uptake both with the purified enzyme and with cytosol from human melanoma cells with high levels of DT-diaphorase activity. P450 reductase and rat liver microsomes also catalyzed NADPH consumption and oxygen uptake. 4-Hydroxyestrone-o-quinone was also rapidly reduced by NAD(P)H; however, this o-quinone does not auto-oxidize and once the o-quinone is reduced the reaction terminates. Including oxidative enzymes in the incubation completes the redox couple and 4-hydroxyestrone-o-quinone behaves like 4-hydroxyequilenin-o-quinone. These data suggest that reduction of estrogen-o-quinones may not result in detoxification. Instead this could represent a cytotoxic mechanism involving consumption of reducing equivalents (NADH/NADPH) as well as formation of superoxide and other reactive oxygen species leading to oxidative stress. Finally, we have compared the cytotoxicity of 4-hydroxyequilenin with that of the estrone catechols in human melanoma cells. 4-Hydroxyequilenin is 5-fold more toxic in these cells compared with 4-hydroxyestrone (ED50 = 7.8 versus 38 microM, respectively) suggesting that formation of the longer-lived redox-active 4-hydroxyequilenin-o-quinone was responsible for the cytotoxic differences. These results substantiate the conclusion that the involvement of quinoids in catechol estrogen toxicity depends on a combination of the rate of formation of the o-quinone, the lifetime of the o-quinone, and the electrophilic/redox reactivity of the quinoids.

Footprinting studies of DNA-sequence recognition by nogalamycin

We have studied the DNA sequence binding preference of the antitumour antibiotic nogalamycin by DNase-I footprinting using a variety of DNA fragments. The DNA fragments were obtained by cloning synthetic oligonucleotides into longer DNA fragments and were designed to contain isolated ligand-binding sites surrounded by repetitive sequences such as (A)n.(T)n and (AT)n. Within regions of (A)n.(T)n, clear footprints are observed with low concentrations of nogalamycin (< 5 microM), with apparent binding affinities for tetranucleotide sequences which decrease in the order TGCA > AGCT = ACGT > TCGA. In contrast, within regions of (AT)n, the ligand binds best to AGCT; binding to TCGA and TGCA is no stronger than to alternating AT. Within (ATT)n, the preference is for ACGT > TCGA. Although each of these binding sites contains all four base pairs, there is no apparent consensus sequence, suggesting that the selectivity is affected by local DNA dynamic and structural effects. At higher drug concentrations (> 25 microM), nogalamycin prevents DNAse-I cleavage of (AT)n but shows no interaction with regions of (AC)n.(GT)n. Regions of (A)n.(T)n, which are poorly cut by DNase I, show enhanced rates of cleavage in the presence of low concentrations of nogalamycin, but are protected from cleavage at higher concentrations. We suggest that this arises because drug binding to adjacent regions distorts the DNA to a structure which is more readily cut by the enzyme and which is better able to bind further ligand molecules.