Focus group study of factors relevant to treatment decisions and experiences among patients with symptomatic peripheral artery disease.

BACKGROUND: Clinical guidelines recommend shared decision-making for treatment of peripheral artery disease (PAD), which requires understanding of patient perspectives and preferences. We conducted a focus group study of patients with symptomatic PAD to identify factors important and relevant to treatment choices, and to characterize aspects of the health care process that contribute to positive vs negative experiences apart from the specific treatment(s) received. METHODS: Participants were recruited from an academic medical center over 2 years using a purposeful sampling approach based on a clinical diagnosis of symptomatic PAD (either claudication or chronic limb-threatening ischemia [CLTI]) confirmed by the abnormal ankle or toe brachial index. Focus groups were led by a nonphysician moderator, consisted of 5 to 12 participants, and were conducted separately for patients with CLTI and claudication. Audio recordings converted to verbatim transcripts were used for qualitative analysis. RESULTS: A total of 51 patients (26 with CLTI and 25 with claudication) were enrolled and participated in focus groups. Major themes identified related to treatment preferences and decisions included specific interventions under consideration, the chance of technical success versus failure, anticipated degree of symptom improvement, outcome durability, and risk. Major themes related to the process of care included decision-making input, provider communication and trust, the timeline from diagnosis to definitive treatment, and compartmentalized care (including different venues of care). CONCLUSIONS: The results provide insights into patient preferences, perspectives, and experiences related to PAD treatment. These observations can be used to inform patient-centered approaches to shared decision-making, communication, and assessment of PAD treatment outcomes.

Significant Phonon Drag Enables High Power Factor in the AlGaN/GaN Two-Dimensional Electron Gas.

In typical thermoelectric energy harvesters and sensors, the Seebeck effect is caused by diffusion of electrons or holes in a temperature gradient. However, the Seebeck effect can also have a phonon drag component, due to momentum exchange between charge carriers and lattice phonons, which is more difficult to quantify. Here, we present the first study of phonon drag in the AlGaN/GaN two-dimensional electron gas (2DEG). We find that phonon drag does not contribute significantly to the thermoelectric behavior of devices with ∼100 nm GaN thickness, which suppresses the phonon mean free path. However, when the thickness is increased to ∼1.2 µm, up to 32% (88%) of the Seebeck coefficient at 300 K (50 K) can be attributed to the drag component. In turn, the phonon drag enables state-of-the-art thermoelectric power factor in the thicker GaN film, up to ∼40 mW m-1 K-2 at 50 K. By measuring the thermal conductivity of these AlGaN/GaN films, we show that the magnitude of the phonon drag can increase even when the thermal conductivity decreases. Decoupling of thermal conductivity and Seebeck coefficient could enable important advancements in thermoelectric power conversion with devices based on 2DEGs.

Exploring patient involvement in decision making for vascular procedures.

BACKGROUND: Developing patient-centered approaches to health care requires increased engagement of patients in their own care, including treatment decisions. Current levels of patient involvement in treatment choices have not been quantified, however, and whether patients desire greater decision-making responsibility is unknown. We conducted a prospective study to explore patients' desired vs experienced roles in treatment decisions, characterize perceptions of treatment outcomes, and identify important sources of information. METHODS: Patients undergoing elective vascular procedures completed a survey consisting of multiple choice, Likert scale, and open-ended questions. Statistics are displayed as mean ± standard deviation or count (%). Differences among procedure categories were evaluated using χ(2) or the Fisher exact test at P < .05 based on responses scored 1 to 2, indicating importance, agreement, or satisfaction based on a 1 to 5 Likert scale where 1 = "very important," "strongly agree" or "very satisfied". RESULTS: Of 101 patients who were contacted, 81 participated. Procedure categories included abdominal aortic aneurysm (AAA) repair in 20, arteriovenous (AV) hemodialysis access in 21, carotid endarterectomy (CEA) in 20, and intervention for lower extremity peripheral arterial disease (PAD) in 20. Participants preferred discussion of all treatments being considered vs only the provider's recommended treatment (90% vs 56%) and choosing together with the provider vs having the provider choose for them (93% vs 62%). Although participants indicated adequate information to ask questions without feeling overwhelmed, only 77% agreed that they had the opportunity to ask questions and only 54% indicated that they were offered a choice. Thirty-seven participants (46%) considered their first treatment was successful, 38% considered a subsequent treatment was successful, and 16% considered none of their treatments were successful. Participants undergoing PAD and AV access procedures most often felt confused or overwhelmed (25% and 24%, respectively, vs 0% for AAA and CEA; P < .01). Patients with PAD had adequate information least often (70% vs 85% for AAA, 100% for AV access, and 95% for CEA; P = .01), had the lowest satisfaction with understanding of their diagnosis (65% vs 95% for AAA, 100% for AV access, and 95% for CEA; P < .01), and most often considered none of their treatments successful (35% vs 0% for AAA, 15% for AV access, and 15% for CEA; P = .02). Providers were identified as the most important information source. CONCLUSIONS: Patients have variable levels of participation in decision making related to vascular procedures and often consider their treatments unsuccessful. Although providers are important sources of information, patients still prefer to discuss all options being considered and contribute to shared decision making.