Citations

R231H Causes a High Penetrance for Familial AFBackgroundAtrial fibrillation (AF) is the most common cardiac arrhythmia, and its incidence is expected to grow. A genetic predisposition for AF has long been recognized, but its manifestation in these patients likely involves a combination of rare and common genetic variants. Identifying genetic variants that associate with a high penetrance for AF would represent a significant breakthrough for understanding the mechanisms that associate with disease.Method and ResultsCandidate gene sequencing in 5 unrelated families with familial AF identified the KCNQ1 missense mutation p.Arg231His (R231H). In addition to AF, several of the family members have abnormal QTc intervals, syncope or experienced sudden cardiac arrest or death. KCNQ1 encodes the voltage‐gated K+ channel that conducts the slowly activating delayed rectifier K+ current in the heart. Functional and computational analyses suggested that R231H increases KCNQ1 current (IKCNQ1) to shorten the atrial action potential (AP) duration. R231H is predicted to minimally affect ventricular excitability, but it prevented the increase in IKCNQ1 following PKA activation. The unique properties of R231H appeared to be caused by a loss in voltage‐dependent gating.ConclusionsThe R231H variant causes a high penetrance for interfamilial early‐onset AF. Our study indicates R231H likely shortens atrial refractoriness to promote a substrate for reentry. Additionally, R231H might cause abnormal ventricular repolarization by disrupting PKA activation of IKCNQ1. We conclude genetic variants, which increase IKs during the atrial AP, decrease the atrial AP duration, and/or shorten atrial refractoriness, present a high risk for interfamilial AF.

BackgroundPrinciples of informed consent are ethically, morally, and legally grounded in physicians' responsibility to patients. This study examined patient expectations regarding the informed consent during the perioperative process, specifically risk information exchange, preferred method and timing of delivery, and the roles that patient anxiety and understanding might play.MethodsFive hundred patients seen in our pre‐operative clinic were surveyed by written questionnaire. Patients were asked about their level of agreement with a number of statements pertaining to informed consent and their preferences for discussion of types of risks. Anxiety concerns, impact of ability to understand complexities of care, preferences for timing, and method of presentation were assessed.ResultsFour hundred eleven of 500 surveys (82%) were completed. A majority of respondents (92% and 80%, respectively) believed the risk of common but less consequential complications and rare yet severe complications should be discussed. Only 21% agreed that anxiety generated by discussion of risks outweighed benefit and only 6% agreed that discussion of risks should be restricted based on patient inability to appreciate complexities of care. Discussion was preferred on the day of surgery, 1 week before, and 1 month before in 46%, 35%, and 16% of respondents, respectively, and independent of level of anxiety generated by such discussion (P = 0.87). Respondents preferred discussion with their anaesthesia provider alone (44%) or in combination with written information (52%) as compared with written information only (4%) (P < 0.01).ConclusionsGreater awareness of patient preferences and expectations may result in better information exchange between anaesthesia providers and their patients.

Background— A hub-and-spoke telestroke network is an effective way to extend quality acute stroke care to remote hospitals and to improve patient outcomes. This study assessed the cost-effectiveness of a telestroke network in the management of acute ischemic stroke from the perspectives of a network, a hub hospital, and a spoke hospital. Methods and Results— A model was developed to compare costs and effectiveness with and without a telestroke network over a 5-year time horizon. The model considered differences in rates of teleconsultations, intravenous thrombolysis, endovascular stroke therapies, and spoke-to-hub transfers. These inputs were estimated through the use of data from Georgia Health Sciences University and Mayo Clinic telestroke networks. A network model with 1 hub and 7 spokes predicted that 45 more patients would be treated with intravenous thrombolysis and 20 more with endovascular stroke therapies per year compared with no network, leading to an estimate of 6.11 more home discharges. Each year, a telestroke network was associated with $358 435 in cost savings; each spoke had $109 080 in cost savings, whereas the hub had positive costs of $405 121. However, cost sharing can be arranged so that each hospital could achieve an equal amount of cost savings ($44 804/y). Results were sensitive to the number of spokes, marginal treatment costs in spokes and rates of transfer, and endovascular stroke therapies. Conclusions— The results of this study suggest that a telestroke network may increase the number of patients discharged home and reduce the costs borne by the network hospitals. Hospitals should consider their available resources and the network features when deciding whether to join or set up a network.

Background. Repetitive facilitative exercise (RFE), a combination of high repetition rate and neurofacilitation, is a recently developed approach to the rehabilitation of stroke-related limb impairment. Preliminary investigations have been encouraging, but a randomized controlled evaluation has yet to be performed. Objectives. To compare the efficacy of RFE with that of conventional rehabilitation in adults with subacute stroke. Methods. A total of 52 adults with stroke-related upper-limb impairment (Brunnstrom stage ≥III) of 3 to 13 weeks’ duration participated in this randomized, controlled, observer-blinded trial. Participants were randomized into 2 groups and received treatment on a 4-week, 40 min/d, 5 d/wk schedule. Those assigned to RFE received 100 standardized movements of at least 5 joints of their affected upper extremity, whereas those in the control group participated in a conventional upper-extremity rehabilitation program. Primary and secondary outcomes (improvement in group Action Research Arm Test [ARAT] and Fugl-Meyer Arm [FMA] scores, respectively) were assessed at the end of training. Results. In all, 49 participants (26 receiving RFE) completed the trial. ARAT and FMA scores at baseline were 19 ± 21 and 39 ± 21 (mean ± standard deviation). Evaluation at the trial’s completion revealed significantly larger improvements in the RFE group than in the control group in both ARAT ( F = 7.52; P = .009) and FMA ( F = 5.98; P = .019) scores. Conclusions. These findings suggest that RFE may be more effective than conventional rehabilitation in lessening impairment and improving upper-limb motor function during the subacute phase of stroke.

AbstractBackground and AimHamartomatous polyposis syndromes (HPS) are a group of rare inherited autosomal dominant disorders. Small bowel polyposis is one of the manifestations of HPS. Double‐balloon enteroscopy (DBE) with polypectomy may obviate repeated small bowel surgeries for polyp intussusception, obstruction, or bleeding. The efficacy and safety of DBE‐assisted polypectomy in HPS patients with clinically significant small bowel polyposis were evaluated.MethodsAll HPS patients who underwent DBE from January 2007 to April 2011 were identified using a prospectively maintained database. Data on patient demographics, pre‐DBE radiological studies, polyp characteristics, procedural outcomes, and complications were abstracted.ResultsTwenty‐two patients underwent a total of 34 DBE procedures. Pre‐DBE imaging included computed tomography enterography (n = 15), computed tomography enteroclysis (n = 5), small bowel follow‐through (n = 1), and magnetic resonance enterography (n = 1). Any small bowel polyp ≥ 1 cm in size on radiological imaging was referred for DBE‐assisted polypectomy. Antegrade and retrograde DBE were successful in reaching and resecting targeted polyps in 90% (18/20) and 71.4% (10/14) of procedures, respectively. The overall success rate for DBE‐assisted polypectomy was 82.3% (95% confidence interval: 66.5–91.6%). The median size of resected polyps was 2 cm (range 1–5 cm) and all were hamartomas. Minor adverse events occurred in four (11.8%) procedures, including abdominal pain (n = 2), immediate post‐polypectomy bleeding (n = 1), and self‐limited hematochezia (n = 1).ConclusionsDBE‐assisted polypectomy was successful in over 80% of HPS patients with an acceptable margin of safety. To the knowledge of the authors, this is one of the largest single‐center studies to report on the performance and safety of DBE‐assisted polypectomy in HPS patients.

Abstract Diffuse idiopathic skeletal hyperostosis (DISH) is a noninflammatory spondyloarthropathy, characterized by ectopic calcification of spinal tissues. Symptoms include spine pain and stiffness, and in severe cases dysphagia and spinal cord compression. The etiology of DISH is unknown and there are no specific treatments. Recent studies have suggested a role for purine metabolism in the regulation of biomineralization. Equilibrative nucleoside transporter 1 (ENT1) transfers hydrophilic nucleosides, such as adenosine, across the plasma membrane. In mice lacking ENT1, we observed the development of calcified lesions resembling DISH. By 12 months of age, ENT1–/– mice exhibited signs of spine stiffness, hind limb dysfunction, and paralysis. Micro–computed tomography (µCT) revealed ectopic mineralization of paraspinal tissues in the cervical-thoracic region at 2 months of age, which extended to the lumbar and caudal regions with advancing age. Energy-dispersive X-ray microanalysis of lesions revealed a high content of calcium and phosphorus with a ratio similar to that of cortical bone. At 12 months of age, histological examination of ENT1–/– mice revealed large, irregular accumulations of eosinophilic material in paraspinal ligaments and entheses, intervertebral discs, and sternocostal articulations. There was no evidence of mineralization in appendicular joints or blood vessels, indicating specificity for the axial skeleton. Plasma adenosine levels were significantly greater in ENT1–/– mice than in wild-type, consistent with loss of ENT1—a primary adenosine uptake pathway. There was a significant reduction in the expression of Enpp1, Ank, and Alpl in intervertebral discs from ENT1–/– mice compared to wild-type mice. Elevated plasma levels of inorganic pyrophosphate in ENT1–/– mice indicated generalized disruption of pyrophosphate homeostasis. This is the first report of a role for ENT1 in regulating the calcification of soft tissues. Moreover, ENT1–/– mice may be a useful model for investigating pathogenesis and evaluating therapeutics for the prevention of mineralization in DISH and related disorders. © 2013 American Society for Bone and Mineral Research.

ObjectiveThe new criteria for preclinical Alzheimer disease (AD) proposed 3 stages: abnormal levels of β‐amyloid (stage 1), stage 1 plus evidence of brain injury (stage 2), and stage 2 plus subtle cognitive changes (stage 3). However, a large group of subjects with normal β‐amyloid biomarkers have evidence of brain injury; we labeled them as the “suspected non‐Alzheimer pathophysiology” (sNAP) group. The characteristics of the sNAP group are poorly understood.MethodsUsing the preclinical AD classification, 430 cognitively normal subjects from the Mayo Clinic Study of Aging who underwent brain magnetic resonance (MR), 18fluorodeoxyglucose (FDG), and Pittsburgh compound B positron emission tomography (PET) were evaluated for FDG PET regional volumetrics, MR regional brain volumetrics, white matter hyperintensity volume, and number of infarcts. We examined cross‐sectional associations across AD preclinical stages, those with all biomarkers normal, and the sNAP group.ResultsThe sNAP group had a lower proportion (14%) with apolipoprotein E ε4 genotype than the preclinical AD stages 2 + 3. The sNAP group did not show any group differences compared to stages 2 + 3 of the preclinical AD group on measures of FDG PET regional hypometabolism, MR regional brain volume loss, cerebrovascular imaging lesions, vascular risk factors, imaging changes associated with α‐synucleinopathy, or physical findings of parkinsonism.InterpretationCognitively normal persons with brain injury biomarker abnormalities, with or without abnormal levels of β‐amyloid, were indistinguishable on a variety of imaging markers, clinical features, and risk factors. The initial appearance of brain injury biomarkers that occurs in cognitively normal persons with preclinical AD may not depend on β‐amyloidosis. ANN NEUROL 2013;73:472–480

Background— Hemodynamic assessment after volume challenge has been proposed as a way to identify heart failure with preserved ejection fraction. However, the normal hemodynamic response to a volume challenge and how age and sex affect this relationship remain unknown. Methods and Results— Sixty healthy subjects underwent right heart catheterization to measure age- and sex-related normative responses of pulmonary capillary wedge pressure and mean pulmonary arterial pressure to volume loading with rapid saline infusion (100–200 mL/min). Hemodynamic responses to saline infusion in heart failure with preserved ejection fraction (n=11) were then compared with those of healthy young (<50 years of age) and older (≥50 years of age) subjects. In healthy subjects, pulmonary capillary wedge pressure increased from 10±2 to 16±3 mm Hg after ~1 L and to 20±3 mm Hg after ~2 L of saline infusion. Older women displayed a steeper increase in pulmonary capillary wedge pressure relative to volume infused (16±4 mm Hg·L −1 ·m 2 ) than the other 3 groups ( P ≤0.019). Saline infusion resulted in a greater increase in mean pulmonary arterial pressure relative to cardiac output in women compared with men regardless of age. Subjects with heart failure with preserved ejection fraction exhibited a steeper increase in pulmonary capillary wedge pressure relative to infused volume (25±12 mm Hg·L −1 ·m 2 ) than healthy young and older subjects ( P ≤0.005). Conclusions— Filling pressures rise significantly with volume loading, even in healthy volunteers. Older women and patients with heart failure with preserved ejection fraction exhibit the largest increases in pulmonary capillary wedge pressure and mean pulmonary arterial pressure.

Background— Stroke occurs more commonly after carotid artery stenting than after carotid endarterectomy. Details regarding stroke type, severity, and characteristics have not been reported previously. We describe the strokes that have occurred in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST). Methods and Results— CREST is a randomized, open-allocation, controlled trial with blinded end-point adjudication. Stroke was a component of the primary composite outcome. Patients who received their assigned treatment within 30 days of randomization were included. Stroke was adjudicated by a panel of board-certified vascular neurologists with secondary central review of clinically obtained brain images. Stroke type, laterality, timing, and outcome were reported. A periprocedural stroke occurred among 81 of the 2502 patients randomized and among 69 of the 2272 in the present analysis. Strokes were predominantly minor (81%, n=56), ischemic (90%, n=62), in the anterior circulation (94%, n=65), and ipsilateral to the treated artery (88%, n=61). There were 7 hemorrhages, which occurred 3 to 21 days after the procedure, and 5 were fatal. Major stroke occurred in 13 (0.6%) of the 2272 patients. The estimated 4-year mortality after stroke was 21.1% compared with 11.6% for those without stroke. The adjusted risk of death at 4 years was higher after periprocedural stroke (hazard ratio, 2.78; 95% confidence interval, 1.63–4.76). Conclusions— Stroke, particularly severe stroke, was uncommon after carotid intervention in CREST, but stroke was associated with significant morbidity and was independently associated with a nearly 3-fold increased future mortality. The delayed timing of major and hemorrhagic stroke after revascularization suggests that these strokes may be preventable. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00004732.