Paul Vos

Geometrical foundations of asymptotic inference

Overview and Preliminaries. ONE-PARAMETER CURVED EXPONENTIAL FAMILIES. First-Order Asymptotics. Second-Order Asymptotics. MULTIPARAMETER CURVED EXPONENTIAL FAMILIES. Extensions of Results from the One-Parameter Case. Exponential Family Regression and Diagnostics. Curvature in Exponential Family Regression. DIFFERENTIAL-GEOMETRIC METHODS. Information-Metric Riemannian Geometry. Statistical Manifolds. Divergence Functions. Recent Developments. Appendices. References. Indexes.

Robotic mitral valve repairs in 300 patients: A single-center experience

OBJECTIVES Mitral valve repair is the standard therapy for patients with degenerative (myxomatous) disease and severe mitral regurgitation. Robotic mitral valve repair provides the least-invasive surgical approach. We report the largest single-center robotic mitral valve repair experience. METHODS Between May 2000 and November 2006, 300 patients underwent a robotic mitral valve repair (daVinci Surgical System; Intuitive Surgical, Inc, Sunnyvale, Calif). All operations were done with 3- to 4-cm right intercostal access, transthoracic aortic occlusion, and peripheral cardiopulmonary bypass. Repairs included 1 or a combination of trapezoidal/triangular leaflet resections, sliding plasties, chordal transfers/replacements, edge-to-edge approximations, and ring annuloplasties. Echocardiographic and survival follow-up were 93% and 100% complete, respectively. RESULTS There were 2 (0.7%) 30-day mortalities and 6 (2.0%) late mortalities. No sternotomy conversions or mitral valve replacements were required. Immediate postrepair echocardiograms showed the following degrees of mitral regurgitation: none/trivial, 294 (98%); mild, 3 (1.0%); moderate, 3 (1.0%); and severe, 0 (0.0%). Complications included 2 (0.7%) strokes, 2 transient ischemic attacks, 3 (1.0%) myocardial infarctions, and 7 (2.3%) reoperations for bleeding. The mean hospital stay was 5.2 +/- 4.2 (standard deviation) days. Sixteen (5.3%) patients required a reoperation. Mean postoperative echocardiographic follow-up at 815 +/- 459 (standard deviation) days demonstrated the following degrees of mitral regurgitation: none/trivial, 192 (68.8%); mild, 66 (23.6%); moderate, 15 (5.4%); and severe, 6 (2.2%). Five-year Kaplan-Meier survival was 96.6% +/- 1.5%, with 93.8% +/- 1.6% freedom from reoperation. CONCLUSIONS Robotic mitral valve repair is safe and is associated with good midterm durability. Further long-term follow-up is necessary.

Hepatosplenic candidiasis in patients with acute leukaemia

A retrospective study of 23 patients with acute leukaemia and hepatosplenic candidiasis (HSC) was conducted to evaluate clinical treatment characteristics in terms of amount and duration of antifungal agents and to assess treatment outcome.

Improved transcutaneous bilirubinometry: comparison of SpectR(X) BiliCheck and Minolta Jaundice Meter JM-102 for estimating total serum bilirubin in a normal newborn population.

OBJECTIVE: To compare a new transcutaneous bilirubinometer, which uses multiple wavelength analysis of reflectance data (BiliCheck system), and the commonly used two-wavelength bilirubinometer (Jaundice Meter JM-102) to estimate serum bilirubin.STUDY DESIGN: Jaundiced newborn term infants (101 babies) had transcutaneous bilirubinometry (TCB) using each bilirubinometer, a determination of skin color using a skin color chart, and a total serum bilirubin determination.RESULTS: The variability of the BiliCheck system was less than the variability of the Jaundice Meter JM-102. The accuracy of the BiliCheck system was not affected by skin color, whereas the Jaundice Meter JM-102 was affected.CONCLUSION: Multiple wavelength analysis, as used in the BiliCheck system, is a significant improvement in TCB.

Robotic Mitral Valve Repair for Anterior Leaflet and Bileaflet Prolapse

BACKGROUND Centers have expanded indications for robotic mitral valve repairs to include complex pathologic features. We studied our results after robotic mitral valve repair for anterior leaflet or bileaflet prolapse. METHODS Data were collected contemporaneously on 289 patients operated on from May 2000 to September 2006. Every patient underwent preoperative transesophageal echocardiography. Follow-up consisted of serial echocardiograms, clinic visits, and phone conversations with patients and their physicians. RESULTS A total of 66 patients (anterior leaflet, n = 14; and bileaflet, n = 52) were identified. Mean age was 52.6 +/- 7.1 years, and 57 (86%) patients had New York Heart Association functional class II or III symptoms. Cardiopulmonary bypass and cross-clamp times were 171 +/- 52 and 132 +/- 39 minutes, respectively. The 30-day and late mortality rates were 3% (n = 2) for each time point. There were no device-related or perfusion-related complications or sternotomy conversions. Complications included 2 strokes (3%), 2 bleeding reexplorations (3%), and 10 pleural effusions requiring intervention (15%). The length of hospital stay for surviving patients was 5 +/- 3 days, and time to extubation averaged 9.5 +/- 13 hours. A total of 6 (9%) patients required valve reoperation. Mean follow-up was 795 +/- 495 days, and echocardiographic mitral regurgitation (n = 60) was none or trace (n = 35, 58.3%), mild (n = 19, 31.6%), moderate (n = 2, 3.3%), and severe (n = 4, 6.7%). CONCLUSIONS Robotic mitral valve repair for anterior leaflet and bileaflet prolapse is feasible and safe. Outcomes and degree of late mitral regurgitation are similar to series using conventional techniques. Long-term follow-up is required to formally address the efficacy of robotic repair techniques.

Functional Communication in Individuals with Chronic Severe Aphasia Using Augmentative Communication

Intervention incorporating augmentative and alternative communication (AAC) is often implemented with adults with aphasia, although studies do not always specify the approaches and strategies used. This study examined abilities of three individuals with chronic non-fluent aphasia (NA) using a dynamic display AAC device to enhance communication. The device, Dialect with Speaking Dynamically Pro, was tailored to each participants skill level using a treatment protocol adapted from Koul, Corwin, and Hayes (). The primary caregiver was the spouse. Pre and post-treatment measures revealed improvement in quality and effectiveness of communication for all participants. Improved linguistic and cognitive functioning was observed for two participants. Results are discussed relative to use of a device with other adults with chronic NA.

Analysis of factors related to the occurrence of chronic disseminated candidiasis in patients with acute leukemia in a non–bone marrow transplant setting

Chronic disseminated candidiasis (CDC) is a serious complication of treatment in patients with acute leukemia. Although some general risk factors are known to predispose to systemic fungal infections, few studies have addressed the relevance of certain clinical and laboratory features in patients with CDC.

Modeling survival in colon cancer: a methodological review

The Cox proportional hazards model is the most widely used model for survival analysis because of its simplicity. The fundamental assumption in this model is the proportionality of the hazard function. When this condition is not met, other modifications or other models must be used for analysis of survival data. We illustrate in this review several methodological approaches to deal with the violation of the proportionality assumption, using survival in colon cancer as an illustrative example.

Analysis of factors influencing aspiration risk following chemoradiation for oropharyngeal cancer

Our aim was to identify risk factors for aspiration following concurrent chemoradiation for oropharyngeal cancer. 46 patients with locally advanced oropharyngeal carcinoma underwent concurrent chemoradiation at our institution. All patients underwent modified barium swallow to assess dysphagia severity and to determine the need for continued tube feedings after treatment. Dysphagia severity was graded as 1-7. There were 5 Grade 2, 11 Grade 3, 5 Grade 4, 5 Grade 5, 10 Grade 6 and 10 Grade 7 scores. 25 patients (54%) developed aspiration (5 trace, 20 severe). The aspiration rate for T1-T2 and T3-T4 tumours was 31% and 67%, respectively (p = 0.03). There was no statistical difference in the aspiration rate between the base of the tongue and tonsillar carcinoma (p = 0.23). Despite anatomical organ preservation, most patients with locally advanced oropharyngeal carcinoma had moderate to severe dysphagia after chemoradiation. Patients with large tumours had a significant risk of developing aspiration following treatment.

Effectiveness of image-guided radiotherapy for laryngeal sparing in head and neck cancer

We would like to compare the effectiveness of image-guided (IGRT) and intensity-modulated (IMRT) radiotherapy to spare the larynx in head and neck cancer patients. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Mean laryngeal and hypopharyngeal dose was compared between 11 patients treated with IMRT and 37 patients treated with IGRT. Mean laryngeal dose was, respectively, 41.2 Gy and 22.8 Gy for the IMRT and IGRT technique (p<0.001). The radiation dose to the middle and inferior pharyngeal muscles was also significantly reduced with the IGRT technique. Mean pharyngeal dose was, respectively, 52 Gy and 26 Gy for the IMRT and IGRT technique (p=0.0001). Laryngeal sparing IGRT technique for head and neck cancer minimizes radiotherapy dose to the larynx and pharynx without sacrificing target coverage, even in the presence of neck lymph nodes.