Evaluating the usability of a co-designed interactive web application for cardiac rehabilitation

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Novartis

Background/significance

The rapid development of information technology is driving the evolution of choices of modes of delivery of healthcare services. The internet is an extremely powerful tool for accessing information, and communication. However, involvement of patients in the assessment of such an intervention is crucial, and can be achieved through a person-centred approach, utilising a co-design process with the aim to increase intervention usability.

Purpose

To assess the usability of the Country Access to Cardiac Health (CATCH) Web, an interactive web application for cardiac rehabilitation (CR), co-designed with rural and remote Australians, following the co-design development phase.

Methods

The User Experience (UX) Design framework was used to co-design the web portal with CR patients through two rounds of six co-design workshops pre (n=39), and post (n=35). Participants and family members living in rural and remote areas of Australia were invited to participate based on their eligibility for CR as outlined by the National Heart Foundation of Australia. As part of the UX Design Framework the System Usability Scale (SUS) was used to measure objective feedback from participants on the website design. The SUS assesses the three core components of a products usability: effectiveness, efficiency and satisfaction using a 10 question Likert scale. Mean scores were compared between the two rounds of workshops using an independent T-Test. The mean SUS score is categorised into poor to moderate (<68), good (68-80.3) and excellent (>=80.3) and categories were compared between the two rounds of workshops through Chi-Square tests.

Results

The 35 participants in the usability workshops had a mean age of 68.6 (SD 11.2) years and 16 (47%) were female (Table 1). The majority had experienced a myocardial infarction (15, 42.8%) and had hyperlipidemia (17, 50%), heart failure (15, 44%), hypertension (14, 41%), and Type II diabetes (7, 21%). Of these participants 20 (59%) used a smart phone, 18 (58%) had access to the National Broadband Network and 20 (59%) engaged with Facebook. From the first to the second round of workshops, there was an improvement in the mean SUS scores from 66.7 (SD16.8) to 73.6 (SD 21.0); p=0.26. The proportion of participants rating it as good or excellent increased from 48.7 to 65.8%; p=0.11 (Figure1).

Conclusion

The usability testing of the interactive CATCH web application showed an improvement in the SUS rating from poor to moderate in the co-design development phase to good or excellent by most of the participants in the usability testing phase. Usability is closely related to engagement with a digital health intervention. Upcoming evaluation of this intervention will report on clinical outcomes.

Abnormal von Willebrand factor secretion, factor VIII stabilization and thrombus dynamics in type 2N von Willebrand disease mice

Essentials Type 2N von Willebrand disease involves impaired von Willebrand factor to factor VIII binding. Type 2N von Willebrand disease mutations exhibit qualitative and mild quantitative deficiencies. Type 2N von Willebrand disease mice exhibit unstable venous hemostatic thrombi. The factor VIII-binding ability of von Willebrand factor regulates arteriole thrombosis dynamics.

SUMMARY

Background von Willebrand factor (VWF) and factor VIII (FVIII) circulate as a non-covalent complex, with VWF serving as the carrier for FVIII. VWF indirectly influences secondary hemostasis by stabilizing FVIII and transporting it to the site of primary hemostasis. Type 2N von Willebrand disease involves impaired binding of VWF to FVIII, resulting in decreased plasma levels of FVIII. Objectives In these studies, we characterize the impact of three type 2N VWD variants (R763A, R854Q, R816W) on VWF secretion, FVIII stabilization and thrombus formation in a murine model. Methods Type 2N VWD mice were generated by hydrodynamic injections of mutant murine VWF cDNAs and the influence of these variants on VWF secretion and FVIII binding was evaluated. In vivo hemostasis and the dynamics of thrombus formation and embolization were assessed using a murine tail vein transection hemostasis model and an intravital thrombosis model in the cremaster arterioles. Results Type 2N VWD variants were associated with decreased VWF secretion using cell and animal-based models. FVIII-binding to type 2N variants was impaired in vitro and was variably stabilized in vivo by expressed or infused 2N variant VWF protein. Both transgenic type 2N VWD and FVIII knockout (KO) mice demonstrated impaired thrombus formation associated with decreased thrombus stability. Conclusions The type 2N VWD phenotype can be recapitulated in a murine model and is associated with both quantitative and qualitative VWF deficiencies and impaired thrombus formation. Patients with type 2N VWD may have normal primary hemostasis formation but decreased thrombus stability related to ineffective secondary hemostasis.

Histones link inflammation and thrombosis through the induction of Weibel-Palade body exocytosis

Essentials Dysregulated DNA and histone release can promote pathological immunothrombosis. Weibel-Palade bodies (WPBs) are sentinel-like organelles that respond to proinflammatory stimuli. Histones induce WPB exocytosis in a caspase, calcium and charge-dependent mechanism. A targetable axis may exist between DNA/histones and WPBs in inflammation and immunothrombosis.

SUMMARY

Background Damage-associated molecular patterns (DAMPs), including molecules such as DNA and histones, are released into the blood following cell death. DAMPs promote a procoagulant phenotype through enhancement of thrombin generation and platelet activation, thereby contributing to immunothrombosis. Weibel-Palade bodies (WPBs) are dynamic endothelial cell organelles that contain procoagulant and proinflammatory mediators, such as von Willebrand factor (VWF), and are released in response to cell stresses. VWF mediates platelet adhesion and aggregation, and has been implicated as a procoagulant component of the innate immune response. Objective To determine the influence of histones and DNA on WPB release, and characterize their association in models of inflammation. Methods We treated C57BL/6J mice and cultured endothelial cells with histones (unfractionated, lysine-rich or arginine-rich) and DNA, and measured WPB exocytosis. We used inhibitors to determine a mechanism of histone-induced WPB release in vitro. We characterized the release of DAMPs and WPBs in response to acute and chronic inflammation in human and murine models. Results and conclusions Histones, but not DNA, induced the release of VWF (1.46-fold) from WBPs and caused thrombocytopenia (0.74-fold), which impaired arterial thrombus formation in mice. Histones induced WPB release from endothelial cells in a caspase-dependent, calcium-dependent and charge-dependent manner, and promoted platelet capture in a flow chamber model of VWF-platelet string formation. The levels of DAMPs and WPB-released proteins were elevated during inflammation, and were positively correlated in chronic inflammation. These studies showed that DAMPs can regulate the function and level of VWF by inducing its release from endothelial WPBs. This DAMP-WPB axis may propagate immunothrombosis associated with inflammation.

A Culturally-Specific Dietary Plan To Manage Weight Gain among African American Breast Cancer Survivors: A Feasibility Study

Background. African American (AA) women are less likely to survive for five years after a breast cancer diagnosis than Caucasian women. The higher prevalence of obesity in AA women may contribute to this disparity. Weight gain following breast cancer treatment is one of the few modifiable risk factors for breast cancer recurrence and mortality. AA breast cancer survivors face unique cultural and economic barriers to adopting diets which reduce the likelihood of weight gain.Objective. To determine the feasibility of adopting and maintaining a culturally-specific low-fat eating plan in a population of low to middle income AA breast cancer survivors.Participants. AA women recruited through urban medical centers who were between 30 to 75 years old, had a confirmed diagnosis of stage 0, I, II, III, or IIIA primary breast cancer, and had incomes < $50,000 per year.Methods. A culturally-specific dietary intervention was developed, based on the Women's Intervention Nutrition Study (WINS), to reduce consumption of dietary fat to 25% of total calories, while increasing fruits and vegetables.Eligible participants were enrolled in a one-year feasibility study. Participants received the Culturally-Specific WINS Low-Fat Eating Plan (WLEP) and 8 individual nutritional counseling sessions with a trained diet technician, to help reduce and maintain their fat intake to 25% of total calories. The intervention also included bi-monthly educational group meetings and follow-up telephone contacts with diet technicians.Study Measures. Dietary patterns were assessed with 3-day food records at baseline and follow-up. Compliance with the Culturally-Specific WLEP was defined as 1) dietary fat intake ≤ 25% of total calories; and 2) at least 6 to 7 servings of fruits and vegetables per day. Psychosocial factors and dietary biomarkers were also measured at baseline and follow-up to examine their association with study outcomes. Psychosocial factors included perceived susceptibility to recurrence, quality of life, and social support. Dietary biomarkers included weight, height, waist-hip circumference, blood pressure, lipids, serum fatty acid concentrations, insulin and insulin-like growth factors, glucose, and levels of sex hormone-binding globulins.Results. A total of 9 AA breast cancer survivors are enrolled and receiving the intervention. Baseline and six-month follow-up results for the psychosocial factors and dietary biomarkers associated with dietary compliance and weight maintenance will be reported in October 2009.Conclusions. A population of low to middle income AA breast cancer survivors with limited education and resources demonstrated compliance with the Culturally-Specific WLEP, thereby reducing their risk of cancer recurrence through diet. Procedures and data from this feasibility study will be used in a multi-center clinical trial of the Culturally-Specific WLEP.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1053.

The laryngeal mask airway: a new standard for airway evaluation in thoracic surgery

BACKGROUND

Thoracic surgeons typically perform fiberoptic bronchoscopy (FOB) before thoracotomy, usually on the day of the operation after intubation with a single-lumen endotracheal tube (ETT) and before insertion of a double-lumen ETT. This routine requires two laryngoscopies and two intubations. The laryngeal mask airway (LMA) is an airway device developed in England and approved by the Food and Drug Administration in 1991 for clinical use in the United States. It requires neither mask ventilation nor laryngoscopy and allows FOB visualization of the epiglottis, larynx, and entire trachea. We assessed the LMA as an alternative to a single-lumen ETT for FOB before thoracotomy.

METHODS

Through prospective assessment, 50 patients underwent FOB after insertion of an LMA before thoracotomy. Pulse rate, blood pressure, ease of insertion of the LMA, quality of FOB, and complications of LMA insertion were assessed.

RESULTS

During LMA insertion, blood pressure and pulse rate increased less than 5% from baseline in all patients. The LMA was inserted successfully in all patients within 10 seconds. No complications occurred as a result of LMA insertion.

CONCLUSIONS

Insertion of the LMA causes minimal hemodynamic response. From the time of induction of general anesthesia, insertion of the LMA is quick, simple, and safe and eliminates the need for endotracheal intubation with a single-lumen ETT before double-lumen tube insertion. The LMA, in contrast to the ETT, allows a complete survey of the larynx and trachea. The LMA is autoclavable, reusable, and cost effective. Therefore, in patients who require FOB immediately before thoracotomy, LMA use should be the standard for airway evaluation.

Participation of alpha 2-adrenergic receptors in neural vascular tone of canine skeletal muscle

Studies were carried out in anesthetized, paralyzed, and ventilated dogs to determine whether postsynaptic alpha 2-adrenergic receptors participated in neurally mediated vascular tone in skeletal muscle. Hindlimb skeletal muscle resistance (RL) and blood flow (QL) were determined before, during, and after reversible cold block of the sciatic nerve. This sequence of observations was repeated 30 min after blockade of alpha 1-adrenergic receptors with prazosin. Then the alpha 2-adrenergic receptors were blocked with yohimbine, and the nerve cold block was repeated. When the sciatic nerve was cold blocked before alpha 1-adrenergic blockade, RL decreased approximately 50% and QL increased 75% (P less than 0.05) and then returned to control when the nerve was rewarmed. After alpha 1-block 76% of neural tone remained as assessed by nerve cooling (P less than 0.05). This phenomenon occurred despite effective alpha 1-adrenergic blockade as assessed by the alpha 1-receptor agonist methoxamine. With alpha 1- plus alpha 2-block no change in RL or QL was seen with nerve cold block. The same protocol was repeated in a second series of animals, but mean arterial pressure, which fell after alpha 1-block in the group above, was maintained by dextran infusion at normotensive levels. In these animals, 40% of neural tone remained after alpha 1-block. Both alpha 1- and alpha 2-adrenergic blockers were again needed to abolish the QL and RL response to nerve cold block. In another series of animals, yohimbine was administered before prazosin. In this series, alpha 2-adrenergic blockade greatly reduced neural tone as assessed by nerve cooling.(ABSTRACT TRUNCATED AT 250 WORDS)

First pass uptake of 14C-propranolol by the lung

Uptake of 14C-propranolol by the lungs during a single passage through the pulmonary circulation was measured in ten patients at cardiac catheterisation. Mean lung uptake of propranolol was 75% in seven patients who were not previously taking the drug and 33% in three patients who were taking it as regular oral treatment. Lung uptake of propranolol in man is therefore considerable and is partly saturable by normal oral doses. This may alter the dose response relation for propranolol and a wide range of other drugs when given intravenously. The method used to study lung uptake is simple and might be suitable for studies of endothelial cell function in disease.