Clinical Outcomes following Left Atrial Appendage Occlusion: A Single-Center Experience

INTRODUCTION

Percutaneous left atrial appendage closure is an established alternative to anticoagulation therapy for stroke prophylaxis among patients with nonvalvular atrial fibrillation. There are currently no guidelines on the choice of antithrombotic therapy following placement of the Watchman® device, the optimal time to discontinue anticoagulation or the duration of follow-up imaging after device deployment. Our main objective was to evaluate clinical outcomes among these patients.

METHODS

We conducted a retrospective review of patients who received a Watchman® device at Mayo Clinic sites between January 2010 and December 2018. We constructed Cox-proportional hazard models to evaluate the effect of specific variables on clinical outcomes.

RESULTS

231 patients were identified (33% female), median age was 77 years, CHA2DS2-VASc score was 5 and HASBLED score was 4. We found no difference in clinically significant bleeding based on initial antithrombotic choice. However, patients with prior gastrointestinal bleeding were more likely to have a bleeding event in the first 6 weeks following Watchman® implantation (HR 9.40, 95% CI 2.15-41.09). Device sizes of 24-27 mm were significantly associated with a decreased risk of thromboembolic events (HR 0.15, 95% CI 0.04-0.55) compared to 21-mm devices. Peridevice leak (PDL) sizes appeared to either remain the same or increase on follow-up imaging.

DISCUSSION/CONCLUSIONS

This observational study showed no statistically significant difference in bleeding risk related to initial antithrombotic choice. Smaller device sizes were associated with thromboembolic events, and longitudinal PDL assessment using transesophageal echocardiography showed these frequently do not decrease in size. Larger studies are needed.

Proposed preliminary diagnostic reference levels for three common interventional cardiology procedures in Ireland

This study has gathered data across Ireland to determine the range of radiation doses received during interventional cardiology (IC) investigations. Radiation doses for three common types of IC examinations where investigated: coronary angiography (CA), percutaneous coronary intervention (PCI) and pacemaker insertions (PPI). A total of 22 cardiac imaging suites participated in the study. Radiation dose was monitored for 1804 adult patients using dose area product (DAP) meters. Individual patient DAP values ranged from 136-23,101 cGy cm2, 475-41,038 cGy cm2 and 45-17,192 cGy cm2 for CA, PCI and PPI respectively, with third quartile values of 4654 cGy cm2, 10,650 cGy cm2 and 1686 cGy cm2. The importance of optimising radiation dose, while not compromising diagnostic efficacy is clear. Although setting reference levels for these complex procedures has some difficulties, it is important that some guideline values are available as a benchmark to guide the operators during these potentially high dose procedures. The third quartile values as described by this paper may offer such guidance.

New protocol for leg ulcer tissue classification from colour images

Measurement of wound healing status is very important for monitoring progress in individual patients. Tissue classification is a vital step in the development of an automatic measurement system for wound healing assessment. We present a new tissue classification protocol using the RGB (Red, Green and Blue) histogram distributions of pixel values from wound color images. These three histogram distributions (extracted features) were used as three two-dimensional (2D) input signals for classification. This protocol has been carried out using the KNN classifier and results show that the proposed protocol provides an extremely competent practical method for the classification of wound tissues.

Identification of lesion components that influence visual function in age related macular degeneration

AIMS

To explore the relation between lesion composition as assessed by fundus photography and fluorescein angiography with clinical measures of vision in eyes of patients with age related macular degeneration (AMD).

METHODS

A standardised visual function assessment along with colour stereo pair fundus photography was carried out in both eyes of 58 subjects with a confirmed clinical diagnosis of AMD. The size, location, and composition of the macular lesion (blood, exudate, subretinal fluid, pigment, membrane, atrophy, and fibrosis) were measured on the colour photographs using computer assisted image analysis. Of the 58 subjects, 44 also had concurrent fluorescein angiography. Classic and occult choroidal neovascularisation (CNV), blood, blocked fluorescence, fibrosis, geographic atrophy, and the total area of abnormal fluorescence were measured. Multiple linear regression was used to examine the relation between clinical measures of vision and the location and extent of lesion components identified by both colour and fluorescein image capture.

RESULTS

The composition of the macular lesion strongly influenced visual function, with atrophy (p=0.001) and fibrosis (p=0.002) accounting for most of the variation. When the location of the lesion with respect to the fovea was examined, fibrosis within the fovea significantly influenced all clinical measures of vision (p=0.008). The regression model selected the total area of abnormal fluorescence and a composite parameter (a semiquantitative measure of the following characteristics: atrophy, exudates, blood, and fibrosis ) from colour photography (r(2) =0.52) as the variables that explained most of the variation in clinical measures of vision.

CONCLUSIONS

The composition and extent of the macular lesion strongly influences visual function in eyes with AMD. Both colour photography and angiography yielded information, which together explained considerably more of the variation in the clinical measures of vision than either on its own.

Improvement of in-rumen digestibility of alfalfa forage by genetic manipulation of lignin O-methyltransferases

Lignin inhibits forage digestibility by ruminant animals, and lignin levels and the proportion of dimethylated syringyl (S) lignin monomers increase with progressive maturity in stems of forage crops. We generated transgenic alfalfa (Medicago sativa L.) with reduced lignin content and altered lignin composition. Down-regulation of caffeic acid 3-O-methyltransferase (COMT) reduces lignin content, accompanied by near total loss of S lignin, whereas down-regulation of caffeoyl coenzyme A 3-O-methyltransferase (CCoAOMT) reduces lignin content without reduction in S lignin. These changes are not accompanied by altered ratios of cell wall polysaccharides. Analysis of rumen digestibility of alfalfa forage in fistulated steers revealed improved digestibility of forage from COMT down-regulated plants, but a greater improvement in digestibility following down-regulation of CCoAOMT. The results indicate that both lignin content and composition affect digestibility of alfalfa forage, and reveal a new strategy for forage quality improvement by genetic manipulation of CCoAOMT expression.

Anaesthesia for magnetic resonance imaging: a survey of current practice in the UK and Ireland

The lack of information about standards for anaesthetic practice in magnetic resonance imaging is of concern, since increasing requests are being made for this service, often in units not designed for the purpose. An overview of current practice was sought by conducting a postal survey of magnetic resonance units in the UK and Ireland. Replies were received from 100 units (79%), 46 of which had an anaesthetic service provided. A wide diversity of practice and opinion on the conduct of anaesthesia in this field was evident from the replies received. The survey highlighted particular areas of concern about the personal safety of anaesthetists within such units, including exposure to magnetic fields, noise and unscavenged anaesthetic gases. The evidence for such concerns is reviewed.

Medical rapid prototyping and 3D CT in the manufacture of custom made cranial titanium plates

This report describes a new method of custom making cranial titanium plates for the repair of skull defects. We have combined 3D CT imaging and surface modelling with rapid prototyping (RP) technology to produce physical models of our patients' skulls from which custom titanium plates were made. We have expanded the use of image processing tools applied to the CT image data to fabricate a representation of the skull defect. Medical RP models are relatively expensive and particular attention has been paid to developing image processing methods to reduce costs. Our technique used the patient as their own model and generated data from the contralateral side of the head where appropriate. We present the results of 10 patients who have had a custom made cranial titanium plate fitted and discuss the models for these cases. The benefits of our custom made titanium plates are reduced patient attendances to hospital and a more accurate titanium plate which has improved fitting and cosmesis.

An evaluation of how MRI is used as a pre-operative screening investigation in patients with temporal lobe epilepsy

AIMS

A retrospective analysis was carried out of how magnetic resonance imaging (MRI) is used as a pre-operative screening investigation in patients with a clinical diagnosis of medically intractable temporal lobe epilepsy (TLE). Up to 65% of such patients are said to have hippocampal sclerosis (HS).

MATERIALS AND METHODS

Forty-six patients in a 26-month period underwent MR examination on a 1.5 T scanner according to a routine protocol. Each patient had coronal T1-weighted and oblique coronal T2-weighted scans performed. Hippocampal volume was calculated from the T1-weighted images, the T2-weighted images being assessed for relative hippocampal signal intensity. Each individual patient's medical records were audited.

RESULTS

Thirty per cent of patients in our study had a diagnosis of HS made on their MR scan. No patient had a diagnosis of HS made without prior clinical evidence of seizure lateralization. Sixty-eight per cent of patients with clinical evidence of a unilateral seizure focus had HS diagnosed by MR scanning. Forty-three per cent of patients did not have clinical evidence of an unilateral seizure focus. It was found that over 25% of patients referred to the unit did not fit the criteria of having medically intractable TLE. Nine per cent of patients had previously stated that they did not want epilepsy surgery.

CONCLUSION

The lower than expected diagnostic rate of HS in this patient population reflects the broad criteria used in referring patients for imaging studies. This is likely to mirror the initial investigation of these patients outside specialist units where more extensive investigation prior to MRI is available. However, when MRI is used as an initial screening investigation, this study indicates that implementation of simple clinical criteria should significantly reduce the number of unnecessary scans.

Serum neurone-specific enolase as an indicator of stroke volume

Serum neurone-specific enolase (NSE) and computerized tomography (CT) stroke volume were compared in patients admitted within 24 h of an acute stroke. Serum samples were obtained on admission and daily for the next 4 days. Of 163 patients, CT scans revealed 25 with intracerebral haemorrhages, one haemorrhagic infarct and 83 measurable acute infarcts. The serum NSE levels of those with infarcts was significantly higher than in those with haemorrhages at 48 (P = 0.0003) and 72 h (P = 0.04). The maximum serum NSE value tended to occur later in those with large infarcts (P = 0.0035). There was a significant correlation between infarct volume and serum NSE at 48 h (r = 0.27, P = 0.015) and 96 h (r = 0.27, P = 0.015) and with the maximum serum NSE over the 4 days (r = 0.36, P = 0.001). There was no significant correlation between haemorrhage volume and NSE. In conclusion, serum NSE may be a useful marker of infarct volume in studies of therapy in acute stroke. Sampling for NSE should continue, at least in those with large infarcts, for longer than 4 days. Serum NSE cannot be used to distinguish between haemorrhage and infarction in patients with an acute stroke.

Triamcinolone acetonide Aqueous nasal spray in patients with seasonal ragweed allergic rhinitis: a placebo-controlled, double-blind study

Because some patients may prefer aqueous nasal sprays and once-daily dosing for relief of seasonal allergic rhinitis symptoms, a new aqueous formulation of triamcinolone acetonide (TAA Aqueous) was developed. We conducted a randomized, placebo-controlled, double-blind study to compare the efficacy and safety of once-daily administration of 220 micrograms/d of TAA Aqueous for 1 week, followed by either 220 micrograms/d or 110 micrograms/d for an additional 2 weeks, with that of placebo in 429 patients with seasonal allergic rhinitis. Patients recorded the severity of symptoms (nasal stuffiness, discharge, sneezing, nasal index [the sum of the first three variables], nasal itching, and eye symptoms) on daily diary cards. Patients' and physicians' global evaluations of efficacy were made at the end of the 3-week study period. Both regimens of TAA Aqueous significantly improved symptoms compared with placebo at most time points. Patients demonstrated significant improvements in nasal symptoms as early as the first day of treatment (within 12 to 16 hours based on treatment in the morning and symptom assessment at bedtime). Although TAA Aqueous 220 micrograms/d provided numerically greater reductions in nasal symptoms compared with 110 micrograms/d, these differences in efficacy over the last 2 weeks were not statistically significant. The incidence of adverse effects with both TAA Aqueous regimens was low and comparable to that of placebo. In summary, during the first week of therapy, TAA Aqueous 220 micrograms/d significantly reduced nasal symptoms. During the last 2 weeks of therapy, the 110 micrograms/d regimen of TAA Aqueous was effective as continued therapy for most patients. Both the 110 micrograms/d and 220 micrograms/d regimens of TAA Aqueous provided significantly better relief of nasal symptoms than did placebo.

Serum neurone specific enolase (NSE) levels as an indicator of neuronal damage in patients with cerebral infarction

A radioimmunoassay has been developed and used to measure serum neurone specific enolase (NSE) concentrations in 24 patients, following cerebral infarction. A significant correlation between cerebral infarct volume and maximum serum NSE concentration was observed (P = 0.047). Serum NSE was also assayed at times 24, 48, 72 and 96 h post ictus. At 72 h a significant correlation existed between serum NSE levels and infarct volume (P = 0.012), and levels appeared to be approaching statistical significance at 48 h (P = 0.067). No correlation existed at 24 and 96 h. In addition serum concentrations of NSE were compared to clinical outcome as determined by the Glasgow Outcome Score. Using the Mann-Whitney U test, there was no significant difference in maximum NSE level between patients graded 1-3 on the Glasgow Outcome Score and those graded 4 and 5. However, further studies are required on a larger population to more completely assess this. NSE may prove to be a useful marker of neuronal damage in the study of stroke, with particular application in the assessment of treatment.

The effect of theophylline and enprofylline on the late cutaneous response to antigen and compound 48/80

Theophylline and enprofylline have been demonstrated to reduce mast cell-mediator release, inhibit polymorphonuclear leukocyte activation, and have been reported to reduce the late bronchial response to antigen. The effects of theophylline and enprofylline on the late cutaneous response (LCR) to compound 48/80 and antigen were studied in 29 patients enrolled in a placebo-controlled, double-blind study of the effect of the xanthines in mild asthma. Skin testing to a common environment allergen and compound 48/80 was performed during a baseline period and in the second phase of the study after stable drug levels were achieved, at least 6 weeks later. During baseline, the mean immediate wheal diameter (IWD) with antigen was 15.7 mm +/- 0.5, resulting in 27/29 LCRs with a mean wheal diameter of 37.1 mm +/- 5.2. The mean IWD with compound 48/80 was 16.1 mm +/- 0.7, resulting in 26/29 LCRs with a mean wheal diameter of 19.6 mm +/- 2.8. Repeat skin testing during treatment revealed no statistically significant changes in the LCR elicited by antigen or 48/80 in any of the treatment groups. There was little correlation between the size of the immediate wheal produced by antigen or 48/80 and the resulting size of the late response (r = 0.174 to 0.519). However, for the same IWD, the resulting late response was smaller with 48/80 than with antigen (p = 0.003). We conclude that (1) theophylline and enprofylline have no effect on the LCR to 48/80 and antigen and (2) for equivalent immediate wheal sizes, the resulting late response is smaller with 48/80 than with antigen.