Invasive Endotyping in Patients With Angina and No Obstructive Coronary Artery Disease: A Randomized Controlled Trial

BACKGROUND

We investigated the usefulness of invasive coronary function testing to diagnose the cause of angina in patients with no obstructive coronary arteries.

METHODS

Outpatients referred for coronary computed tomography angiography in 3 hospitals in the United Kingdom were prospectively screened. After coronary computed tomography angiography, patients with unobstructed coronary arteries, and who consented, underwent invasive endotyping. The diagnostic assessments included coronary angiography, fractional flow reserve (patient excluded if ≤0.80), and, for those without obstructive coronary artery disease, coronary flow reserve (abnormal <2.0), index of microvascular resistance (abnormal ≥25), and intracoronary infusion of acetylcholine (0.182, 1.82, and 18.2 μg/mL; 2 mL/min for 2 minutes) to assess for microvascular and coronary spasm. Participants were randomly assigned to disclosure of the results of the coronary function tests to the invasive cardiologist (intervention group) or nondisclosure (control group, blinded). In the control group, a diagnosis of vasomotor angina was based on medical history, noninvasive tests, and coronary angiography. The primary outcome was the between-group difference in the reclassification rate of the initial diagnosis on the basis of coronary computed tomography angiography versus the final diagnosis after invasive endotyping. The Seattle Angina Questionnaire summary score and Treatment Satisfaction Questionnaire for Medication were secondary outcomes.

RESULTS

Of 322 eligible patients, 250 (77.6%) underwent invasive endotyping; 19 (7.6%) had obstructive coronary disease, 127 (55.0%) had microvascular angina, 27 (11.7%) had vasospastic angina, 17 (7.4%) had both, and 60 (26.0%) had no abnormality. A total of 231 patients (mean age, 55.7 years; 64.5% women) were randomly assigned and followed up (median duration, 19.9 [12.6-26.9] months). The clinician diagnosed vasomotor angina in 51 (44.3%) patients in the intervention group and in 55 (47.4%) patients in the control group. After randomization, patients in the intervention group were 4-fold (odds ratio, 4.05 [95% CI, 2.32-7.24]; P<0.001) more likely to be diagnosed with a coronary vasomotor disorder; the frequency of this diagnosis increased to 76.5%. The frequency of normal coronary function (ie, no vasomotor disorder) was not different between the groups before randomization (51.3% versus 50.9%) but was reduced in the intervention group after randomization (23.5% versus 50.9%, P<0.001). At 6 and 12 months, the Seattle Angina Questionnaire summary score in the intervention versus control groups was 59.2±24.2 (2.3±16.2 change from baseline) versus 60.4±23.9 (4.6±16.4 change) and 63.7±23.5 (4.7±14.7 change) versus 66.0±19.3 (7.9±17.1 change), respectively, and not different between groups (global P=0.36). Compared with the control group, global treatment satisfaction was higher in the intervention group at 12 months (69.9±22.8 versus 61.7±26.9, P=0.013).

CONCLUSIONS

For patients with angina and no obstructive coronary arteries, a diagnosis informed by invasive functional assessment had no effect on long-term angina burden, whereas treatment satisfaction improved.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03477890.

The coronary microvascular angina cardiovascular magnetic resonance imaging trial: Rationale and design

BACKGROUND

Coronary microvascular dysfunction may cause myocardial ischemia with no obstructive coronary artery disease (INOCA). If functional testing is not performed INOCA may pass undetected. Stress perfusion cardiovascular MRI (CMR) quantifies myocardial blood flow (MBF) but the clinical utility of stress CMR in the management of patients with suspected angina with no obstructive coronary arteries (ANOCA) is uncertain.

OBJECTIVES

First, to undertake a diagnostic study using stress CMR in patients with ANOCA following invasive coronary angiography and, second, in a nested, double-blind, randomized, controlled trial to assess the effect of disclosure on the final diagnosis and health status in the longer term.

DESIGN

All-comers referred for clinically indicated coronary angiography for the investigation of suspected coronary artery disease will be screened in 3 regional centers in the United Kingdom. Following invasive coronary angiography, patients with ANOCA who provide informed consent will undergo noninvasive endotyping using stress CMR within 3 months of the angiogram.

DIAGNOSTIC STUDY

Stress perfusion CMR imaging to assess the prevalence of coronary microvascular dysfunction and clinically significant incidental findings in patients with ANOCA. The primary outcome is the between-group difference in the reclassification rate of the initial diagnosis based on invasive angiography versus the final diagnosis after CMR imaging.

RANDOMIZED, CONTROLLED TRIAL

Participants will be randomized to inclusion (intervention group) or exclusion (control group) of myocardial blood flow to inform the final diagnosis. The primary outcome of the clinical trial is the mean within-subject change in the Seattle Angina Questionnaire summary score (SAQSS) at 6 months. Secondary outcome assessments include the EUROQOL EQ-5D-5L questionnaire, the Brief Illness Perception Questionnaire (Brief-IPQ), the Treatment Satisfaction Questionnaire (TSQM-9), the Patient Health Questionnaire-4 (PHQ-4), the Duke Activity Status Index (DASI), the International Physical Activity Questionnaire- Short Form (IPAQ-SF), the Montreal Cognitive Assessment (MOCA) and the 8-item Productivity Cost Questionnaire (iPCQ). Health and economic outcomes will be assessed using electronic healthcare records.

VALUE

To clarify if routine stress perfusion CMR imaging reclassifies the final diagnosis in patients with ANOCA and whether this strategy improves symptoms, health-related quality of life and health economic outcomes.

CLINICALTRIALS

GOV: NCT04805814.

Microvascular arterial disease of the brain and the heart: a shared pathogenesis

Microvascular arterial disease in the heart manifest as coronary microvascular dysfunction. This condition causes microvascular angina and is associated increased morbidity and mortality. Microvascular arterial disease in the brain is referred to as cerebrovascular small vessel disease. This is responsible for 45% of dementias and 25% of ischaemic strokes. The heart and brain share similar vascular anatomy and common pathogenic risk factors are associated with the development of both coronary microvascular dysfunction and cerebrovascular small vessel disease. Microvascular disease in the heart and brain also appear to share common multisystem pathophysiological mechanisms. Further studies on diagnostic approaches, epidemiology and development of disease-modifying therapy seem warranted.

General practitioner views on the determinants of test ordering: a theory-based qualitative approach to the development of an intervention to improve immunoglobulin requests in primary care

BACKGROUND

Research suggests that variation in laboratory requesting patterns may indicate unnecessary test use. Requesting patterns for serum immunoglobulins vary significantly between general practitioners (GPs). This study aims to explore GP's views on testing to identify the determinants of behaviour and recommend feasible intervention strategies for improving immunoglobulin test use in primary care.

METHODS

Qualitative semi-structured interviews were conducted with GPs requesting laboratory tests at Cork University Hospital or University Hospital Kerry in the South of Ireland. GPs were identified using a Health Service Executive laboratory list of GPs in the Cork-Kerry region. A random sample of GPs (stratified by GP requesting patterns) was generated from this list. GPs were purposively sampled based on the criteria of location (urban/rural); length of time qualified; and practice size (single-handed/group). Interviews were carried out between December 2014 and February 2015. Interviews were transcribed verbatim using NVivo 10 software and analysed using the framework analysis method. Emerging themes were mapped to the theoretical domains framework (TDF), which outlines 12 domains that can enable or inhibit behaviour change. The behaviour change wheel and behaviour change technique (BCT) taxonomy were then used to identify potential intervention strategies.

RESULTS

Sixteen GPs were interviewed (ten males and six females). Findings suggest that intervention strategies should specifically target the key barriers to effective test ordering, while considering the context of primary care practice. Seven domains from the TDF were perceived to influence immunoglobulin test ordering behaviours and were identified as 'mechanisms for change' (knowledge, environmental context and resources, social/professional role and identity, beliefs about capabilities, beliefs about consequences, memory, attention and decision-making processes and behavioural regulation). Using these TDF domains, seven BCTs emerged as feasible 'intervention content' for targeting GPs' ordering behaviour. These included instructions on how to effectively request the test (how to perform behaviour), information on GPs' use of the test (feedback on behaviour), information about patient consequences resulting from not doing the test (information about health consequences), laboratory/consultant-based advice/education (credible source), altering the test ordering form (restructuring the physical environment), providing guidelines (prompts/cues) and adding interpretive comments to the results (adding objects to the environment). These BCTs aligned to four intervention functions: education, persuasion, environmental restructuring and enablement.

CONCLUSIONS

This study has effectively applied behaviour change theory to identify feasible strategies for improving immunoglobulin test use in primary care using the TDF, 'behaviour change wheel' and BCT taxonomy. The identified BCTs will form the basis of a theory-based intervention to improve the use of immunoglobulin tests among GPs. Future research will involve the development and evaluation of this intervention.

Does contact with a podiatrist prevent the occurrence of a lower extremity amputation in people with diabetes? A systematic review and meta-analysis

OBJECTIVE

To determine the effect of contact with a podiatrist on the occurrence of Lower Extremity Amputation (LEA) in people with diabetes.

DESIGN AND DATA SOURCES

We conducted a systematic review of available literature on the effect of contact with a podiatrist on the risk of LEA in people with diabetes. Eligible studies, published in English, were identified through searches of PubMed, CINAHL, EMBASE and Cochrane databases. The key terms, 'podiatry', 'amputation' and 'diabetes', were searched as Medical Subject Heading terms. Reference lists of selected papers were hand-searched for additional articles. No date restrictions were imposed.

STUDY SELECTION

Published randomised and analytical observational studies of the effect of contact with a podiatrist on the risk of LEA in people with diabetes were included. Cross-sectional studies, review articles, chart reviews and case series were excluded. Two reviewers independently assessed titles, abstracts and full articles to identify eligible studies and extracted data related to the study design, characteristics of participants, interventions, outcomes, control for confounding factors and risk estimates.

ANALYSIS

Meta-analysis was performed separately for randomised and non-randomised studies. Relative risks (RRs) with 95% CIs were estimated with fixed and random effects models as appropriate.

RESULTS

Six studies met the inclusion criteria and five provided data included in meta-analysis. The identified studies were heterogenous in design and included people with diabetes at both low and high risk of amputation. Contact with a podiatrist did not significantly affect the RR of LEA in a meta-analysis of available data from randomised controlled trials (RCTs); (1.41, 95% CI 0.20 to 9.78, 2 RCTs) or from cohort studies; (0.73, 95% CI 0.39 to 1.33, 3 Cohort studies with four substudies in one cohort).

CONCLUSIONS

There are very limited data available on the effect of contact with a podiatrist on the risk of LEA in people with diabetes.

Factors associated with staffing provision and medical equipment acquisition in Irish general practice

GPs form an integral part of Irish primary care provision. However, current information concerning general practice structure, staffing and development in Ireland is quite limited. This report provides a profile of General Practice in Ireland in 2010 drawing on a national survey of practices using a standardised questionnaire. On average, there are 2.7 GPs per practice, although one in four practices remains single-handed. The majority of practices employ nursing 485 (80.7%) and clerical 549 (91.3%) support. A high proportion of practices have the following items of equipment: ECG machine 496 (82.5%), 24 hour blood pressure monitor 481 (80.1%), spirometer 383 (63.8%), cryotherapy equipment 505 (84%), minor surgery equipment 453 (74.3%) and foetal monitor 484 (80.5%). Using chi-square analysis, we find statistically significant positive relationships between nursing support and possession of each of the six items of medical equipment (chi2 = 81.57, p < 0.01; chi2 = 105.4, p < 0.01; 2 = 38.5, p < 0.01; chi2 = 16.6, p < 0.01; chi2 = 39.5, p < 0.01; = 19.5, p < 0.01) and between practice size and possession of each item of medical equipment (chi2 = 26.3, p < 0.01; chi2 = 45, p < 0.01; chi2 = 16.5, p < 0.01; chi2 = 44.4, p < 0.01; chi2 = 13.8, p < 0.01; chi2 = 14.7, p < 0.01).

Experiment-model interaction for analysis of epicardial activation during human ventricular fibrillation with global myocardial ischaemia

We describe a combined experiment-modelling framework to investigate the effects of ischaemia on the organisation of ventricular fibrillation in the human heart. In a series of experimental studies epicardial activity was recorded from 10 patients undergoing routine cardiac surgery. Ventricular fibrillation was induced by burst pacing, and recording continued during 2.5 min of global cardiac ischaemia followed by 30 s of coronary reflow. Modelling used a 2D description of human ventricular tissue. Global cardiac ischaemia was simulated by (i) decreased intracellular ATP concentration and subsequent activation of an ATP sensitive K⁺ current, (ii) elevated extracellular K⁺ concentration, and (iii) acidosis resulting in reduced magnitude of the L-type Ca²⁺ current I(Ca,L). Simulated ischaemia acted to shorten action potential duration, reduce conduction velocity, increase effective refractory period, and flatten restitution. In the model, these effects resulted in slower re-entrant activity that was qualitatively consistent with our observations in the human heart. However, the flattening of restitution also resulted in the collapse of many re-entrant waves to several stable re-entrant waves, which was different to the overall trend we observed in the experimental data. These findings highlight a potential role for other factors, such as structural or functional heterogeneity in sustaining wavebreak during human ventricular fibrillation with global myocardial ischaemia.

A computational study of mother rotor VF in the human ventricles

Sudden cardiac death is one of the major causes of death in the industrialized world. It is most often caused by a cardiac arrhythmia called ventricular fibrillation (VF). Despite its large social and economical impact, the mechanisms for VF in the human heart yet remain to be identified. Two of the most frequently discussed mechanisms observed in experiments with animal hearts are the multiple wavelet and mother rotor hypotheses. Most recordings of VF in animal hearts are consistent with the multiple wavelet mechanism. However, in animal hearts, mother rotor fibrillation has also been observed. For both multiple wavelet and mother rotor VF, cardiac heterogeneity plays an important role. Clinical data of action potential restitution measured from the surface of human hearts have been recently published. These in vivo data show a substantial degree of spatial heterogeneity. Using these clinical restitution data, we studied the dynamics of VF in the human heart using a heterogeneous computational model of human ventricles. We hypothesized that this observed heterogeneity can serve as a substrate for mother rotor fibrillation. We found that, based on these data, mother rotor VF can occur in the human heart and that ablation of the mother rotor terminates VF. Furthermore, we found that both mother rotor and multiple wavelet VF can occur in the same heart depending on the initial conditions at the onset of VF. We studied the organization of these two types of VF in terms of filament numbers, excitation periods, and frequency domains. We conclude that mother rotor fibrillation is a possible mechanism in the human heart.

Organization of ventricular fibrillation in the human heart: experiments and models

Sudden cardiac death is a major health problem in the industrialized world. The lethal event is typically ventricular fibrillation (VF), during which the co-ordinated regular contraction of the heart is overthrown by a state of mechanical and electrical anarchy. Understanding the excitation patterns that sustain VF is important in order to identify potential therapeutic targets. In this paper, we studied the organization of human VF by combining clinical recordings of electrical excitation patterns on the epicardial surface during in vivo human VF with simulations of VF in an anatomically and electrophysiologically detailed computational model of the human ventricles. We find both in the computational studies and in the clinical recordings that epicardial surface excitation patterns during VF contain around six rotors. Based on results from the simulated three-dimensional excitation patterns during VF, which show that the total number of electrical sources is 1.4 +/- 0.12 times greater than the number of epicardial rotors, we estimate that the total number of sources present during clinically recorded VF is 9.0 +/- 2.6. This number is approximately fivefold fewer compared with that observed during VF in dog and pig hearts, which are of comparable size to human hearts. We explain this difference by considering differences in action potential duration dynamics across these species. The simpler spatial organization of human VF has important implications for treatment and prevention of this dangerous arrhythmia. Moreover, our findings underline the need for integrated research, in which human-based clinical and computational studies complement animal research.

Alcohol--how much is too much?

The aims of this study were to examine perceptions of what a sample of students and graduates consider an excessive alcohol intake to be and it's effect on their health. 115 University College Cork (UCC) students and 133 UCC graduates were questioned about their opinions of an acceptable weekly intake of alcohol. The results reveal dramatic changes in drinking habits over recent decades. Students began drinking earlier than graduates and are far more accepting of greater amounts of alcohol being consumed. The student's average opinion of what constituted an excessive weekly alcohol intake was 26.5 units of alcohol/week whereas the graduates felt over 18 units/week was too much. We concluded that even amongst these highly educated cohorts there is a low level of awareness of safe limits of alcohol consumption.

Targeted nNOS gene transfer into the cardiac vagus rapidly increases parasympathetic function in the pig

Nitric oxide (NO) derived from neuronal nitric oxide synthase (nNOS) facilitates cardiac vagal neurotransmission and bradycardia in vitro. Here we provide evidence of rapid (within 9 h) protein expression and increased vagal responsiveness in vivo following targeted gene transfer of nNOS into the cardiac vagus of the pig. Right vagi were injected with vector encoding nNOS (Ad.nNOS) or saline, while left vagi received an injection of vector encoding enhanced green fluorescent protein (Ad.eGFP). Enhanced nNOS protein expression was detected exclusively in the right vagus nerve, with no evidence of iNOS expression. This was associated with increased baroreflex sensitivity and greater heart rate responsiveness to right vagal stimulation. In contrast, responsiveness of left vagi, or sham-injected right vagi remained constant over the same time period. Basal heart rate was unchanged following gene transfer, suggesting no change in vagal tone. These results support the pre-/post-ganglionic synapse as a site for NO-mediated facilitation of vagal bradycardia in the pig. In addition they demonstrate in vivo that functional gene expression induced with adenoviral vectors occurs earlier than first thought, and may therefore, provide a novel intervention to acutely modulate the neural control of cardiac excitability.

The computational performance of a high-order coupled FEM/BEM procedure in electropotential problems

This paper presents a thorough analysis of the computational performance of a coupled cubic Hermite boundary element/finite element procedure. This C1 (i.e., value and derivative continous) method has been developed specifically for electropotential problems, and has been previously applied to torso and skull problems. Here, the behavior of this new procedure is quantified by solving a number of dipole in spheres problems. A detailed set of results generated with a wide range of the various input parameters (such as dipole orientation, location, conductivity, and solution method used in each spherical shell [either finite element or boundary elements]) is presented. The new cubic Hermite boundary element procedure shows significantly better accuracy and convergence properties and a significant reduction in CPU time than a traditional boundary element procedure which uses linear or constant elements. Results using the high-order method are also compared with other computational methods which have had quantitative results published for electropotential problems. In all cases, the high-order method offered a significant improvement in computational efficiency by increasing the solution accuracy for the same, or fewer, solution degrees of freedom.

Noninvasive electrical imaging of the heart: theory and model development

The aim of this work is to begin quantifying the performance of a recently developed activation imaging algorithm of Huiskamp and Greensite [IEEE Trans. Biomed. Eng. 44:433-446]. We present here the modeling and computational issues associated with this process. First, we present a practical construction of the appropriate transfer matrix relating an activation sequence to body surface potentials from a general boundary value problem point of view. This approach makes explicit the role of different Green's functions and elucidates features (such as the anisotropic versus isotropic distinction) not readily apparent from alternative formulations. A new analytic solution is then developed to test the numerical implementation associated with the transfer matrix formulation presented here and convergence results for both potentials and normal currents are given. Next, details of the construction of a generic porcine model using a nontraditional data-fitting procedure are presented. The computational performance of this model is carefully examined to obtain a mesh of an appropriate resolution to use in inverse calculations. Finally, as a test of the entire approach, we illustrate the activation inverse procedure by reconstructing a known activation sequence from simulated data. For the example presented, which involved two ectopic focii with large amounts of Gaussian noise (100 microV rms) present in the torso signals, the reconstructed activation sequence had a similarity index of 0.880 when compared to the input source.

Prescribing new drugs: qualitative study of influences on consultants and general practitioners

OBJECTIVE

To explore consultants' and general practitioners' perceptions of the factors that influence their decisions to introduce new drugs into their clinical practice.

DESIGN

Qualitative study using semistructured interviews. Monitoring of hospital and general practice prescribing data for eight new drugs.

SETTING

Teaching hospital and nearby general hospital plus general practices in Birmingham.

PARTICIPANTS

38 consultants and 56 general practitioners who regularly referred to the teaching hospital.

MAIN OUTCOME MEASURES

Reasons for prescribing a new drug; sources of information used for new drugs; extent of contact between consultants and general practitioners; and amount of study drugs used in hospitals and by general practitioners.

RESULTS

Consultants usually prescribed new drugs only in their specialty, used few new drugs, and used scientific evidence to inform their decisions. General practitioners generally prescribed more new drugs and for a wider range of conditions, but their approach varied considerably both between general practitioners and between drugs for the same general practitioner. Drug company representatives were an important source of information for general practitioners. Prescribing data were consistent with statements made by respondents.

CONCLUSIONS

The factors influencing the introduction of new drugs, particularly in primary care, are more multiple and complex than suggested by early theories of drug innovation. Early experience of using a new drug seems to strongly influence future use.

Giving voice to the lifeworld. More humane, more effective medical care? A qualitative study of doctor-patient communication in general practice

Mishler (The discourse of medicine. The dialectics of medical interviews. Norwood, NJ: Ablex), applying Habermas's theory of Communicative Action to medical encounters. showed how the struggle between the voice of medicine and the voice of the lifeworld fragmented and suppressed patients' multi-faceted, contextualised and meaningful accounts. This paper investigates and critiques Mishler's premise that this results in inhumane, ineffective medical care. Using a more complex data collection strategy, comprising patient interviews, doctor interviews and transcribed consultations we show more complex relations than emerged from Mishler's analysis. We found four communication patterns across 35 general practice case studies. When doctor and patient both used the voice of medicine exclusively (acute physical complaints) this worked for simple unitary problems (Strictly Medicine). When both doctor and patient engaged with the lifeworld, more of the agenda was voiced (Mutual Lifeworld) and patients were recognised as unique human beings (psychological plus physical problems). Poorest outcomes occurred where patients used the voice of the lifeworld but were ignored (Lifeworld Ignored) or blocked (Lifeworld Blocked) by doctors' use of voice of medicine (chronic physical complaints). The analysis supports the premise that increased use of the lifeworld makes for better outcomes and more humane treatment of patients as unique human beings. Some doctors switched communication strategies in different consultations, which suggests that their behaviour might be open to change. If doctors could be sensitised to the importance of dealing with the concerns of the lifeworld for patients with chronic physical conditions as well as psychological conditions, it might be possible to obtain better care for patients. This would require attention to structural aspects of the healthcare system to enable doctors to work fully within the patient-centred model.

Proton pump inhibitors: a study of GPs' prescribing

BACKGROUND

There has been a rapid increase in proton pump inhibitor (PPI) prescribing in recent years, and controlling the cost and improving the quality of prescribing is an issue of concern to many GPS:

OBJECTIVE

Our aim was to compare GPs' usage of different PPIs and explore how GPs' PPI prescribing changes following the introduction of a cheaper competitor.

METHODS

PPI prescribing data (PACT) for 53 GPs, who were selected as regular users of a teaching hospital, were monitored from January 1995 to December 1997. The GPs were located in two adjoining health districts and had been interviewed about influences on their decisions to begin prescribing lansoprazole. The PPI prescribing data were collected for the teaching hospital and the general hospital in the adjoining district.

RESULTS

Complete prescribing data were available for 50 GPS: Total PPI prescribing increased throughout the study due mainly to increasing use of the new PPIS: Use of the new PPIs increased from 6 to 24% over 3 years. The proportion of maintenance doses prescribed increased from 3 to 12%. There was a 23-fold difference in total PPI prescribing and an 87-fold difference in lansoprazole prescribing between the highest and lowest prescribers. The uptake of pantoprazole was slower than that of lansoprazole. A rapid increase in the use of lansoprazole by the GPs followed an increase in use in the teaching hospital.

CONCLUSION

Hospital prescribing was an important influence on the choice of PPI used by GPS: The wide variation in PPI prescribing suggests that there is scope for improvement in the quality and cost of PPI prescribing.

Effects of material properties and geometry on electrocardiographic forward simulations

This paper investigates the effect on torso potentials of changes in the material properties of the torso volume conductor and changes in the relative geometry of the heart and torso. The investigations are performed using a number of forward simulations with a high-order coupled finite element/boundary element torso model. This torso model contains descriptions of the epicardium, lungs, skeletal muscle (with a continuously varying fiber field) and subcutaneous fat. The number of nodes, elements and solution degrees-of-freedom used in the computational torso model are considerably smaller than previous torso models of similar complexity. The successful forward simulations in this paper hence demonstrate the use of the high-order coupled approach with realistic problems. The results of the torso simulations show that the torso inhomogeneities do affect the torso potentials but do not affect the distribution or pattern of the torso potentials. The inhomogeneities considered are found to have a varying, but important, effect on the torso potentials. The effect of the subcutaneous fat is found to be more important and the effect of the skeletal muscle is found to be less important than previous reports in the literature. The results also show that the relative geometry of the heart and torso is very important in determining the torso potential magnitudes and distributions.

Patients' unvoiced agendas in general practice consultations: qualitative study

OBJECTIVE

To investigate patients' agendas before consultation and to assess which aspects of agendas are voiced in the consultation and the effects of unvoiced agendas on outcomes.

DESIGN

Qualitative study.

SETTING

20 general practices in south east England and the West Midlands.

PARTICIPANTS

35 patients consulting 20 general practitioners in appointment and emergency surgeries.

RESULTS

Patients' agendas are complex and multifarious. Only four of 35 patients voiced all their agendas in consultation. Agenda items most commonly voiced were symptoms and requests for diagnoses and prescriptions. The most common unvoiced agenda items were: worries about possible diagnosis and what the future holds; patients' ideas about what is wrong; side effects; not wanting a prescription; and information relating to social context. Agenda items that were not raised in the consultation often led to specific problem outcomes (for example, major misunderstandings), unwanted prescriptions, non-use of prescriptions, and non-adherence to treatment. In all of the 14 consultations with problem outcomes at least one of the problems was related to an unvoiced agenda item.

CONCLUSION

Patients have many needs and when these are not voiced they can not be addressed. Some of the poor outcomes in the case studies were related to unvoiced agenda items. This suggests that when patients and their needs are more fully articulated in the consultation better health care may be effected. Steps should be taken in both daily clinical practice and research to encourage the voicing of patients' agendas.

Doctor-patient communication about drugs: the evidence for shared decision making

The traditional paternalistic model of medical decision-making, in which doctors make decisions on behalf of their patients, has increasingly come to be seen as outdated. Moreover, the role of the patient in the consultation has been emphasised, notably through the adoption of 'patient-centred' strategies. Models that promote patients' active involvement in the decision-making process about treatment have been developed. We examine one particular model of shared decision making [Charles, C., Gafni, A., Whelan, T, 1997. Shared decision-making in the medical encounter: what does it mean? (or it takes at least two to tango). Social Science & Medicine 44, 681-692.]. The model has four main characteristics. These are that (1) both the patient and the doctor are involved, (2) both parties share information, (3) both parties take steps to build a consensus about the preferred treatment and (4) an agreement is reached on the treatment to implement. Focusing on the first two of the four characteristics of the model, we use the findings from a study of 62 consultations, together with interviews conducted with patients and general practitioners, to consider participation in the consultation in terms of sharing information about, and views of, medicines. We found little evidence that doctors and patients both participate in the consultation in this way. As a consequence there was no basis upon which to build a consensus about the preferred treatment and reach an agreement on which treatment to implement. Thus even the first two of the four conditions said to be necessary for shared decision making were not generally present in the consultations we studied. These findings were presented in feedback sessions with participating GPs, who identified a number of barriers to shared decision making, as well as expressing an interest in developing strategies to overcome these barriers.

Misunderstandings in prescribing decisions in general practice: qualitative study

OBJECTIVES

To identify and describe misunderstandings between patients and doctors associated with prescribing decisions in general practice.

DESIGN

Qualitative study.

SETTING

20 general practices in the West Midlands and south east England.

PARTICIPANTS

20 general practitioners and 35 consulting patients.

MAIN OUTCOME MEASURES

Misunderstandings between patients and doctors that have potential or actual adverse consequences for taking medicine.

RESULTS

14 categories of misunderstanding were identified relating to patient information unknown to the doctor, doctor information unknown to the patient, conflicting information, disagreement about attribution of side effects, failure of communication about doctor's decision, and relationship factors. All the misunderstandings were associated with lack of patients' participation in the consultation in terms of the voicing of expectations and preferences or the voicing of responses to doctors' decisions and actions. They were all associated with potential or actual adverse outcomes such as non-adherence to treatment. Many were based on inaccurate guesses and assumptions. In particular doctors seemed unaware of the relevance of patients' ideas about medicines for successful prescribing.

CONCLUSIONS

Patients' participation in the consultation and the adverse consequences of lack of participation are important. The authors are developing an educational intervention that builds on these findings.

GPs' perceptions of patient influence on prescribing

BACKGROUND

Controlling prescribing costs is an issue of concern to many GPs.

OBJECTIVE AND METHODS

This paper is based on interviews with 21 GPs in which they were asked about influences on prescribing budgets.

RESULTS

The results presented relate specifically to GPs' perceptions of the influence of patients on prescribing. Perceptions of patient demand were described both in terms of a general demand and demand by patients with specific health beliefs or particular social characteristics. Generally, GPs reported that decisions to prescribe were informed by a concern to maintain a good relationship with their patients, and not to risk the relationship by not prescribing when they believed a prescription was expected.

CONCLUSIONS

Although information was available about whether practices had a 'high' or 'low' budget, and whether they were under- or overspent, there did not appear to be any relationship between GPs' beliefs that patient expectations affected their prescribing and whether they were under or over budget. This paper suggests that patient demand for prescriptions may not only be overestimated but also perpetuated by GPs' belief in its existence and a wish to maintain a good doctor-patient relationship.

Patient attitudes to over-the-counter drugs and possible professional responses to self-medication

BACKGROUND

There is a paucity of research about patients' attitudes towards their doctor's recommending over-the-counter (OTC) remedies or about how patients respond to the doctor's suggestion to try an OTC remedy.

OBJECTIVES

The aim of this study was to ascertain the attitudes of patients to OTC drugs.

METHODS

505 consecutive patients from each of six participating practices filled in a questionnaire.

RESULTS

A total of 2765 (91.3%) patients responded. The responses from 2624 patients were from adults and are presented here. Based on the number of valid responses to each question, 53.8% of these patients were exempt from prescription charges, 55.1% took regular prescribed medication and 24.6% stated that they used OTC remedies regularly. There were generally positive attitudes to doctors enquiring about prior OTC use as well as to doctors making OTC recommendations in the consultation. However, patients expressed fairly negative attitudes towards pharmacists making generic substitutions and were even more hostile to the idea that pharmacists should make therapeutic substitutions.

CONCLUSION

In conclusion, GPs should consider asking their patients regularly about their use of OTC medicines and also consider recommending OTC use if this is cheaper than FP10s. However, the public at present do not appear to be prepared for interventions by the pharmacist.

Primary care--opportunities and threats. Developing prescribing in primary care

The latest white papers on the NHS focus on stimulating innovation in the delivery of primary care and removing barriers to further development. Some of this innovation relates directly to prescribing in primary care, and in this article the authors speculate on what might happen if the prescribing initiatives referred to in the white papers were extended and disseminated more widely. The initiatives which might have the biggest impact are those encouraging closer collaboration between general practitioners and community pharmacists and those aiding extension of the current nurse prescribing scheme in primary care. Both offer considerable opportunities to improve primary care, but both bear some potential risks.

Geometric modeling of the human torso using cubic hermite elements

We discuss the advantages and problems associated with fitting geometric data of the human torso obtained from magnetic resonance imaging, with high-order (bicubic Hermite) surface elements. These elements preserve derivative (C1) continuity across element boundaries and permit smooth anatomically accurate surfaces to be obtained with relatively few elements. These elements are fitted to the data with a new nonlinear fitting procedure that minimizes the error in the fit while maintaining C1 continuity with nonlinear constraints. Nonlinear Sobelov smoothing is also incorporated into this fitting scheme. The structures fitted along with their corresponding root mean-squared error, number of elements used, and number of degrees of freedom (df) per variable are: epicardium (0.91 mm, 40 elements, 142 df), left lung (1.66 mm, 80 elements, 309 df), right lung (1.69 mm, 80 elements. 309 df), skeletal muscle surface (1.67 mm, 264 elements, 1,010 df), fat layer (1.79 mm, 264 elements, 1.010 df), and the skin layer (1.43 mm, 264 elements, 1,010 df). The fitted surfaces are assembled into a combined finite element/boundary element model of the torso in which the exterior surfaces of the heart and lungs are modeled with two-dimensional boundary elements and the layers of the skeletal muscle, fat, and skin are modeled with finite elements. The skeletal muscle and fat layers are modeled with bicubic Hermite linear elements and are obtained by joining the adjacent surface elements for each layer. Applications for the torso model include the forward and inverse problems of electrocardiography, defibrillation studies, radiation dosage studies, and heat transfer studies.

Evaluation of computerized decision support for oral anticoagulation management based in primary care

BACKGROUND

Increasing indications for oral anticoagulation has led to pressure on general practices to undertake therapeutic monitoring. Computerized decision support (DSS) has been shown to be effective in hospitals for improving clinical management. Its usefulness in primary care has previously not been investigated.

AIM

To test the effectiveness of using DSS for oral anticoagulation monitoring in primary care by measuring the proportions of patients adequately controlled, defined as within the appropriate therapeutic range of International Normalised Ratio (INR).

METHOD

All patients receiving warfarin from two Birmingham inner city general practices were invited to attend a practice-based anticoagulation clinic. In practice A all patients were managed using DSS. In practice B patients were randomized to receive dosing advice either through DSS or through the local hospital laboratory. Clinical outcomes, adverse events and patient acceptability were recorded.

RESULTS

Forty-nine patients were seen in total. There were significant improvements in INR control from 23% to 86% (P > 0.001) in the practice where all patients received dosing through DSS. In the practice where patients were randomized to either DSS or hospital dosing, logistic regression showed a significant trend for improvement in intervention patients which was not apparent in the hospital-dosed patients (P < 0.001). Mean recall times were significantly extended in patients who were dosed by the practice DSS through the full 12 months (24 days to 36 days) (P = 0.033). Adverse events were comparable between hospital and practice-dosed patients, although a number of esoteric events occurred. Patient satisfaction with the practice clinics was high.

CONCLUSION

Computerized DSS enables the safe and effective transfer of anticoagulation management from hospital to primary care and may result in improved patient outcome in terms of the level of control, frequency of review and general acceptability.

Increasing the number of drugs available over the counter: arguments for and against

Many drugs previously restricted to prescription only status are being reclassified as pharmacy only status and hence are becoming available over the counter to patients. A general practitioner should make enquiries about a patient's self-medication practices before deciding on treatment for the patient. Over-the-counter medicines are considered safe and their increased use indicates that patients are taking greater responsibility for their own health and possibly taking some of the financial burden of drug treatment from the National Health Service. The retention of their restriction to pharmacy only sale provides some additional protection for patients and promotes the role of pharmacists in the care of patients. However, having more drugs available for self-treatment may encourage patients to believe that there is a drug treatment for every ailment. Increasing the range of drugs available over the counter increases the risks of interactions and adverse reactions and of self-treatment being undertaken when medical aid should have been sought. For general practitioners to recommend positively use of over-the-counter preparations may involve some medicolegal risks, and the potential savings to the NHS may prove illusory. Education for patients and better communication between general practitioners and community pharmacists are required to allow easier availability of modern medicines to patients in order to bring the benefits anticipated.

Factors which influence the decision whether or not to prescribe: the dilemma facing general practitioners

In this study of the influences affecting general practitioners' decisions whether or not to prescribe, 69 principals and five trainees in general practice were asked about the factors that made these decisions difficult for them and the circumstances in which the decision caused them to feel uncomfortable. Discomfort was reported most frequently in prescribing for respiratory disease, psychiatric conditions and skin problems, though the range of problems mentioned was wide. The range of drugs for which the decision of whether or not to prescribe was difficult was also wide but psychotropic drugs, antibiotics, drugs acting on the cardiovascular system and non-steroidal anti-inflammatory drugs were most often mentioned. Patient factors said to be important included age, ethnicity, social class and education, the doctor's prior knowledge of the patient, the doctor's feeling towards the patient, communication problems, and the doctor's desire to try to preserve the doctor-patient relationship. Doctor specific factors included concerns about drugs, factors relating to doctors' role perception and expectations of themselves, uncertainty, peer influences, logistic factors, and the experience of medical or therapeutic misadventures. The results of this study support earlier work on the influence of social factors on prescribing decisions and show that this influence affects the entire range of clinical problems. The results also reveal the importance of logistic factors. The overriding concern of doctors to preserve the doctor-patient relationship and the range of attitudes, perceptions and experiences of doctors that have a bearing on the decision to prescribe begin to explain the apparent irrationality of some general practitioner prescribing.(ABSTRACT TRUNCATED AT 250 WORDS)

Turning anecdotes into data--the critical incident technique

This article describes the critical incident technique and offers practical guidance on how the technique can be used to investigate dilemmas in medicine. It extols the particular virtue of this research method for general practice that it can be used to exploit the natural tendency of doctors to tell anecdotes. How the principles of the technique relate to significant event analysis, a form of medical audit, is also discussed.

Uncomfortable prescribing decisions: a critical incident study

OBJECTIVE

To explore the discomfort experienced by general practitioners in relation to decisions about whether or not to prescribe.

DESIGN

Focused interviews of general practitioners about prescribing decisions that made them uncomfortable. Analysis based on the critical incident technique.

SETTING

One family practitioner committee area in the north of England.

RESPONDENTS

69 principals and five trainee general practitioners.

MAIN OUTCOME MEASURES

Drugs and clinical problems associated with prescribing discomfort. Reasons given by doctors for making the prescribing decisions they did and reasons for feeling uncomfortable.

RESULTS

Antibiotics, tranquillisers, hypnotics, and symptomatic remedies were most often associated with discomfort, but any prescribable item could be associated with discomfort. Respiratory diseases, musculoskeletal problems, and anxiety were most often associated with discomfort, but again any condition could be associated. The main reasons given for the decisions made were patient expectation, clinical appropriateness, factors related to the doctor-patient relationship, and precedents. The main reasons given for feeling uncomfortable were concern about drug toxicity, failure to live up to the general practitioner's own expectations, concern about the appropriateness of treatment, and ignorance or uncertainty.

CONCLUSIONS

Many considerations, including medical, social, and logistic ones, influence the decision to prescribe in general practice. The final action taken depends on a complex interaction of these disparate influences.

Decision making and prescribing patterns--a literature review

This paper reviews the literature on the variation in prescribing patterns and attempts which have been made to relate such variation to characteristics of doctors. Subsequent efforts to identify the correlates of good prescribing are described and the flaws in this approach are highlighted. It is argued that further understanding of prescribing behaviour requires a study of the underlying decision making processes. The literature on three key decisions relating to prescribing is reviewed. Studies of drug adoption and relinquishment from 1966 to 1991 are described. The drug selection process in individual consultations is also discussed and, in particular, the evidence for the 'drug choice model' is assessed. Finally, the decision to treat is considered and the lack of empirical evidence in this area is highlighted.