Intraoperative transit time flow measurements during off-pump coronary artery bypass surgery: The impact of coronary stenosis on competitive flow

Background

Combining preoperative angiography findings with intraoperative transit time flow measurements (TTFM) may improve patency of coronary artery bypass grafts. Nevertheless, graft flow might be impaired by native coronary flow based on the severity of stenoses, with inferior long‐term outcomes. This study investigates the impact of left anterior descending artery (LAD) stenosis on competitive flow measured in left internal mammary artery (LIMA) grafts during off‐pump coronary artery bypass grafting.

Methods

Fifty patients were included in this prospective single‐center cohort study. LAD stenosis was assessed with quantitative coronary analysis (QCA) and stratified into three groups based on its severity. TTFM of LIMA grafts were performed with LAD open and temporarily occluded. Change in mean graft flow after LAD snaring was the primary endpoint. Secondary endpoints included further TTFM parameters, clinical outcomes, and competitive flow index (CFI), defined as the ratio of mean graft flow with open or closed LAD.

Results

Mean LAD stenosis as objectified with QCA was 58 ± 15%. Mean LIMA graft flow increased from 20 ml/min with open LAD to 30 ml/min with snared LAD (p < .001). TTFM cut‐off values for graft patency improved in 26%–42% of patients after LAD occlusion. Median CFI was 0.66 (IQR: 0.56–0.82). Postoperative myocardial infarction occurred in 2.0% of patients, 120‐day mortality was 0%, and 2‐year mortality was 6.0%.

Conclusions

Routine snaring of the LAD with CFI calculation during coronary artery bypass grafting is useful to detect significant competitive flow in LIMA grafts, potentially preventing unnecessary intraoperative graft revisions.

Contrast-enhanced ultrasound for quantification of tissue perfusion in humans

Contrast-enhanced ultrasound is an imaging technique that can be used to quantify microvascular blood volume and blood flow of vital organs in humans. It relies on the use of microbubble contrast agents and ultrasound-based imaging of microbubbles. Over the past decades, both ultrasound contrast agents and experimental techniques to image them have rapidly improved, as did experience among investigators and clinicians. However, these improvements have not yet resulted in uniform guidelines for CEUS when it comes to quantification of tissue perfusion in humans, preventing its uniform and widespread use in research settings. The objective of this review is to provide a methodological overview of CEUS and its development, the influences of hardware and software settings, type and dosage of ultrasound contrast agent, and method of analysis on CEUS-derived perfusion data. Furthermore, we will discuss organ-specific imaging challenges, advantages, and limitations of CEUS.

Clinical and inflammatory phenotyping by breathomics in chronic airway diseases irrespective of the diagnostic label

Asthma and chronic obstructive pulmonary disease (COPD) are complex and overlapping diseases that include inflammatory phenotypes. Novel anti-eosinophilic/anti-neutrophilic strategies demand rapid inflammatory phenotyping, which might be accessible from exhaled breath.Our objective was to capture clinical/inflammatory phenotypes in patients with chronic airway disease using an electronic nose (eNose) in a training and validation set.This was a multicentre cross-sectional study in which exhaled breath from asthma and COPD patients (n=435; training n=321 and validation n=114) was analysed using eNose technology. Data analysis involved signal processing and statistics based on principal component analysis followed by unsupervised cluster analysis and supervised linear regression.Clustering based on eNose resulted in five significant combined asthma and COPD clusters that differed regarding ethnicity (p=0.01), systemic eosinophilia (p=0.02) and neutrophilia (p=0.03), body mass index (p=0.04), exhaled nitric oxide fraction (p<0.01), atopy (p<0.01) and exacerbation rate (p<0.01). Significant regression models were found for the prediction of eosinophilic (R²=0.581) and neutrophilic (R²=0.409) blood counts based on eNose. Similar clusters and regression results were obtained in the validation set.Phenotyping a combined sample of asthma and COPD patients using eNose provides validated clusters that are not determined by diagnosis, but rather by clinical/inflammatory characteristics. eNose identified systemic neutrophilia and/or eosinophilia in a dose-dependent manner.

A systematic review of quantitative and qualitative research on the role and effectiveness of written information available to patients about individual medicines

OBJECTIVES

To establish the role and value of written information available to patients about individual medicines from the perspective of patients, carers and professionals. To determine how effective this information is in improving patients' knowledge and understanding of treatment and health outcomes.

DATA SOURCES

Electronic databases searched to late 2004, experts in information design, and stakeholder workshops (including patients and patient organisations).

REVIEW METHODS

Data from selected studies were tabulated and the results were qualitatively synthesised along with findings from the information design and stakeholder workshop strands.

RESULTS

Most people do not value the written information they receive. They had concerns about the use of complex language and poor visual presentation and in most cases the research showed that the information did not increase knowledge. The research showed that patients valued written information that was tailored to their individual circumstances and illness, and that contained a balance of harm and benefit information. Most patients wanted to know about any adverse effects that could arise. Patients require information to help decision-making about whether to take a medicine or not and (once taking a medicine) with ongoing decisions about the management of the medicine and interpreting symptoms. Patients did not want written information to be a substitute for spoken information from their prescriber. While not everyone wanted written information, those who did wanted sufficient detail to meet their need. Some health professionals thought that written information for patients should be brief and simple, with concerns about providing side-effect information. They saw increasing compliance as a prime function, in contrast to patients who saw an informed decision not to take a medicine as an acceptable outcome.

CONCLUSIONS

The combination of a quantitative and qualitative review, an exploration of best practice in information design, plus the input of patients at stakeholder workshops, allowed this review to look at all perspectives. There is a gap between currently provided leaflets and information which patients would value and find more useful. The challenge is to develop methods of provision flexible enough to allow uptake of varying amounts and types of information, depending on needs at different times in an illness. This review has identified a number of areas where future research could be improved in terms of the robustness of its design and conduct, and the use of patient-focused outcomes. The scope for this research includes determining the content, delivery and layout of statutory leaflets that best meet patients' needs, and providing individualised information, which includes both benefit and harm information. In particular, studies of the effectiveness and role and value of Internet-based medicines information are needed.