In medical diagnostic research, medical tests with continuous values are widely employed to distinguish between diseased and non-diseased subjects. The diagnostic accuracy of a medical test can be assessed by using the receiver operating characteristic (ROC) curve of the test. To summarize the ROC curve and determine an optimal cut-off point for test results, the Youden index is commonly used. In particular, the Youden index is optimized over the entire range of values for sensitivity and specificity, which determine the ROC space. However in clinical practice, one may only be interested in the regions of the ROC curve that correspond to low false-positive rates or/and high sensitivities. In this paper, a new summary index for the ROC curve, called the “partial Youden index”, is defined on regions of the ROC space in which sensitivity/specificity values are of practical interest. The traditional Youden index is a special case of the partial Youden index. Various parametric and non-parametric interval estimation methods are proposed for the partial Youden index. Extensive simulation studies are conducted to evaluate the finite sample performances of the proposed methods. A real example is used to illustrate the application of the new methods. 相似文献
Background: Videolaparoscopic (VL) microwave ablation (MWA) is not included in most of the international guidelines as a therapeutic option for hepatocellular carcinoma (HCC). Aim of this study was to assess the safety of VL MWA in patients with HCC for whom resection or percutaneous ablation is unsuitable. Methods: A retrospective analysis was performed on a prospective database of patients with HCC treated with VL MWA at our institution from 2009 to 2016. Patient demographics, operational characteristics, and complications were recorded. Statistical analysis was performed to identify safety profile, overall survival and recurrence rate. Results: A total of 815 VL MWA were performed in 674 patients with a mean age of 64 years. Patients had a mean Model for End-stage Liver Disease score of 10 (±3); 32.8% were Child B, 44.1% Barcelona Clinic Liver Cancer B-C. Perioperative mortality was 0.4%. Overall morbidity was 30.8%, with Dindo-Clavien complications ≥3 in 2%. The median length of stay was 2 days. In 43.1% VL MWA was the first-line therapy. Overall 1-, 3-, and 5-year survival rates were 81.9%, 54.9%, and 35.9%. Conclusions: The present is the largest series of VL ablation and the bigger number of patients with HCC treated with MW reported nowadays. It confirms the safety of a minimally invasive procedure for patients with HCC when resection or percutaneous ablation is not feasible. 相似文献
Objective: To compare the operation time and performance of two uterine manipulators used for total laparoscopic hysterectomy (TLH).
Material and methods:Design: Retrospective cohort analysis. Design classification: Canadian Task Force Classification II-2. Setting: Tertiary-care university-based teaching hospital and academic affiliated private hospital. Patients: All consecutive patients who underwent for TLH between January 2014 and June 2017. All operations were performed by two expert endoscopic surgeons using one of the following uterine manipulators depending on surgeon preferences: Clermont-Ferrand (CF) or Vectec (VT) MAUT60. Patients were excluded if additional surgeries such as urogynecological procedures were performed, TLH was converted to laparotomy prior to colpotomy, and when their operation records could not be obtained. A total of 169 patients were added to final analysis. Operation time, colpotomy time and the subjective performance of manipulators such as movement of the uterus, visualization of the vaginal fornices, and maintenance of pneumoperitoneum were evaluated by watching un-edited operation videos.
Results: A total of 169 patients (83 patients in CF group; 86 patients in VT group) were included in the final analysis. Patients’ baseline characteristics were comparable between groups. Operation time and time required for colpotomy were significantly shorter in the VT group. Lateral movements of the manipulators and elevation of the uterus were better with VT compared to CF (p?=?.001 for both). Compared to the CF, VT was superior for visualization of the vaginal fornices (p?=?.004) and maintenance of pneumoperitoneum (p?<?.001). Both surgeons had perfect agreement on the performance grading of manipulators (p?<?.001, Kappa values were between 0.86–0.92). There was no difference between groups in estimated blood loss and duration of hospital stay. Reinsertion or the need to change the manipulator was not required in either group. No pelvic or vaginal abscess, cuff cellulitis, dehiscence, or hematoma formations were noted.
Conclusion: Laparoscopic hysterectomy assisted with the VT uterine manipulator is associated with shorter operation and colpotomy time. Furthermore, the movements of uterus, visualization of the vaginal fornices, and maintenance of pneumoperitoneum were significantly better with VT compared to the CF manipulator. 相似文献
Exercise intolerance is the cardinal symptom of heart failure (HF) and is of crucial relevance, because it is associated with a poor quality of life and increased mortality. While impaired cardiac reserve is considered to be central in HF, reduced exercise and functional capacity are the result of key patient characteristics and multisystem dysfunction, including aging, impaired pulmonary reserve, as well as peripheral and respiratory skeletal muscle dysfunction. We herein review the different modalities to quantify exercise intolerance, the pathophysiology of HF, and comorbid conditions as they lead to reductions in exercise and functional capacity, highlighting the fact that distinct causes may coexist and variably contribute to exercise intolerance in patients with HF. 相似文献
ObjectiveThe clinical and neurophysiological characteristics of myoclonus in Angelman syndrome (AS) have been evaluated in single case or small cohorts, with contrasting results. We evaluated the features of myoclonus in a wide cohort of AS patients.MethodsWe performed polygraphic EEG-EMG recording in 24 patients with genetically confirmed AS and myoclonus. Neurophysiological investigations included jerk-locked back-averaging (JLBA), cortico-muscular coherence (CMC) and generalised partial directed coherence (GPDC). CMC and GPDC analyses were compared to those obtained from 10 healthy controls (HC).ResultsTwenty-four patients (aged 3–35 years, median 20) were evaluated. Sequences of quasi-continuous rhythmic jerks mostly occurred at alpha frequency or just below (mean 8.4 ± 1.4 Hz), without EEG correlate. JLBA did not show any clear transient preceding the jerks. CMC showed bilateral over-threshold CMC in alpha band that was prominent on the contralateral hemisphere in the patient group as compared to HC group. GPDC showed a significantly higher alpha outflow from both hemispheres toward activated muscles in the patient group, and a significantly higher beta outflow from contralateral hemisphere in the HC group.ConclusionsThese neurophysiological findings suggest a subcortical generator of myoclonus in AS.SignificanceMyoclonus in AS has not a cortical origin as previously hypothesised. 相似文献
Phaeochromocytomas and paragangliomas (PPGL) are catecholamine-secreting neuroendocrine tumours. These tumours may be identified incidentally, as part of a work-up for multiple endocrine neoplasia or following haemodynamic surges during unrelated procedures. Advances in preoperative management and improved management of intraoperative haemodynamic instability have significantly reduced surgical mortality from around 40% to less than 3%. Surgery is the definitive treatment in most cases and laparoscopic resection where possible is associated with improved outcomes. Anaesthetic management of PPGL cases represents a unique haemodynamic challenge both before, during and after tumour resection. In this article we describe the physiology of these tumours, their diagnosis, preoperative optimization methods, intraoperative anaesthetic management and management of postoperative complications. 相似文献