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Prospective comparison of infrainguinal bypass grafting in patients with and without antiphospholipid antibodies.

PURPOSE: The antiphospholipid antibodies (APL)-anticardiolipin antibodies (ACL) and lupus anticoagulant (LA)-are widely believed to be associated with decreased lower extremity bypass graft patency rates. To date, no prospective cohort study has confirmed this assumption. A prospective comparison of the result of infrainguinal revascularization procedures performed since 1990 in patients with and without APL forms the basis of this report. METHODS: Patients who underwent elective infrainguinal bypass procedures from 1990 to 1994 were evaluated for hypercoagulable states (ACL, LA, protein C, protein S, and antithrombin III). Patient data were prospectively entered in a computerized vascular registry, and postoperative follow-up was maintained for life. Graft patency, limb salvage, and patient survival rates were calculated by life-table methods. RESULTS: Three hundred twenty-seven lower extremity bypass grafting procedures were performed in 262 patients. APLs were present in 83 patients (32%); 70 patients (84%) had ACLs only, 11 patients (13%) had LA only, and two patients (3%) had both ACLs and LA. There was no significant difference between APL-positive and APL-negative patients with respect to demographics, associated medical conditions, indication for operations, and type of procedures performed. More patients who had APLs had warfarin treatment after surgery (43% vs 24%, p = 0.002). Life table 4-year primary patency rates showed minimal difference (APL-positive, 43%; APL-negative, 59%; p = 0.087), and no significant difference was noted in assisted primary patency rates (APL positive, 72%; APL negative, 73%; p = NS), limb salvage rates (APL positive, 79%; APL negative, 88%; p = NS), and patient survival rates (APL positive, 67%; APL negative, 66%; p = NS). CONCLUSIONS: APLs were found in a surprising one third of the patients who underwent leg bypass grafting procedures. The majority of APLs identified were ACLs (87%). There was minimal difference in graft primary patency rates, and no difference in assisted primary patency, limb salvage, and survival rates between patients with and without APLs who underwent leg bypass grafting procedures. The extreme morbidity rate associated with APLs in previous reports is not confirmed by this prospective study. APLs should not be regarded as a contraindication to indicated leg bypass grafting procedures.

Aged↗

Operative mortality and long-term survival of patients operated on for acute lower limb ischaemia.

OBJECTIVES: To investigate the operative mortality and long-term survival of patients with lower limb embolism or acute thrombosis. DESIGN: A retrospective survival analysis. MATERIALS: Eighty patients with acute thrombosis treated by bypass and 192 patients with embolism treated by embolectomy during the years from 1985 to 1996 were studied. METHODS: The observed survival rates were calculated with the product limit method. The expected survival rates were estimated from death-rate tables. The standard mortality rate was compared over a 5-year follow-up. RESULTS: The patients treated for embolism had an operative mortality of 17% and a 5-year survival rate of 17%, which was significantly lower than the expected rate of 62%. Those treated for acute thrombosis had an operative mortality of 14% and a 5-year survival rate of 44%. This was significantly higher than for the embolism group, but significantly lower than the expected rate of 74%. Both groups had a standard mortality rate of 2.2 at 5 years. CONCLUSION: Patients with acute ischaemia have a poor short-term and long-term prognosis. The patients treated for embolism are older and they have a shorter life expectancy than those treated for acute thrombosis. The standard mortality rate of the two groups appears similar.

Aged↗

Corneal graft survival: a retrospective Australian study.

Four hundred and forty-eight consecutive corneal grafts are analysed and their survival calculated using the actuarial life-table method. Overall survival at two years is 81 +/- 4% and at five years is 65 +/- 5%. Within diagnostic subgroups keratoconus has the best prognosis. Previous graft failure and recipient corneal vascularization are shown to have a negative effect on graft survival. Sex of patient, urgency of operation and use of combined procedures do not affect survival and second regrafts fare no worse than first regrafts. The use of the actuarial life-table method of analysing graft survival is discussed and its importance emphasized.

Actuarial Analysis↗

Conservative management of residual and recurrent lesions after carotid endarterectomy: long-term results.

PURPOSE: To document the natural history of residual and recurrent carotid stenoses that are initially treated without surgery, and to identify risk factors for recurrent stenosis. METHODS: Review of data from a prospective carotid database with clinical and duplex follow-up. Analysis of rate of restenosis and rate of late reoperation by life table. Risk factor analysis by chi 2 and LEE-DESU statistics. RESULTS: Three hundred forty-eight patients were available for follow-up, with 12 residual lesions (3.7%) and 22 recurrent lesions (6.6%). Rate of recurrent stenosis by life table analysis was 8.7% and 13% at 3 and 5 years. Restenosis was associated with smoking (p = 0.04) and contralateral progression. Only 21% of patients were underwent an operation within 5 years (p = 0.007) of restenosis developing, but eventually 10 of 22 patients required reoperation at long-term follow-up, eight for symptoms and two for progressive proximal stenoses. The late stroke rate was increased in patients who had residual or recurrent lesions compared with those who had normal duplex study results (18% vs 6%; p = 0.16) and was related to the ipsilateral artery. CONCLUSIONS: Recurrent lesions that remain asymptomatic can be managed without operation with likelihood of success in the near term (5 years). However, these patients are at increased risk of late stroke, and almost half will eventually require operation. Therefore, in good-risk patients operation for asymptomatic restenosis should be considered.

Aged↗

[Technology integration and process management. Concept and implementation of a new platform for simultaneous diagnosis and therapy of acutely ill and injured patients and for elective computer assisted surgery (CAS)].

Modern imaging and computer technology gain more and more importance in surgery. This is true for elective and emergency diagnosis and treatment. However integration of technology and optimization of process management is severely behind. A new diagnostic-therapeutic platform should balance this deficit. The platform is composed of a fully equipped operation room environment with integrated high end computer-tomography with navigation, a digital subtraction angiography and an OR- and imaging-table particularly developed for this set-up. The platform may be used for elective diagnosis, for diagnosis and therapy in polytraumatized patients in one and the same location (one stop shop) and for computer assisted surgery (CAS). Bringing the technology to the patient and not the patient to the technology can save time consuming and potentially dangerous transports and expensive personnel can be reduced. Navigation-technology and high quality intra-operative imaging expand the spectrum of minimally invasive surgery.

Diagnostic Imaging↗

ESWL and endourology on the same table: a feasible concept?

Within 26 months a total of 4,126 procedures were performed on the ESWL multipurpose table. Forty percent of the procedures were comprised of endourology, 25% functional urinary tract radiology, and 37% ESWL therapy. Biplane fluoroscopy is an extraordinary help for percutaneous interventions. A further advantage is the possibility to perform endourology and ESWL in one session without having to transport the patient. This has facilitated pre- and post-operative ancillary measures in a total of 35.3%. Seventy-six percent of stones greater than 15 mm were managed via indwelling stents. In situ ESWL for ureteral stones has become the therapy of choice in more than 80% of patients due to the availability of radiological localization systems and a complication and failure rate of 20% for the push-and-smash procedure. The multipurpose table is equally successful as the piezoelectric system for ESWL therapy. Drawbacks include operational inconvenience with percutaneous interventions and the necessity to change patient position during ureterorenoscopy and retrograde pyelography. The multipurpose unit used is a valid compromise for ESWL and percutaneous endourology. For purely diagnostic interventions, a standard x-ray table is preferred.

Adolescent↗

3D optoelectronic analysis of interfractional patient setup variability in frameless extracranial stereotactic radiotherapy.

PURPOSE: To investigate size and frequency of interfractional patient setup variability in hypofractionated stereotactic extracranial radiotherapy. METHODS AND MATERIALS: Infrared optical 3D tracking of surface markers was applied to quantify setup variability on 51 patients. Isocenter position repeatability was assessed by means of frameless anatomic calibration and was compared with portal image evaluation. Specific data analysis allowed for compensation of patients' breathing movements and for separation of the effects of operator-dependent misalignments and respiration-induced displacements. Effects of patient position (supine vs. prone) and treatment table configuration were investigated. RESULTS: Patient positioning assisted by the optical tracking device allowed reducing displacements of surface control points within the 3-mm range. Errors in isocenter localization were in the range of a few millimeters. This was in agreement with the portal image evaluation. Breathing motion introduced appreciable errors, which increased control points and isocenter 3D variability. This effect was significantly higher than those related to other investigated factors. CONCLUSIONS: The role of infrared optical tracking devices for patient positioning is assessed on a large patient population. Their use in the frame of high-precision radiotherapy is emphasized by the application of related methodologies for breathing phase detection and frameless isocenter localization.

Abdominal Neoplasms↗

Comparison of surgical performance during laparoscopic radical prostatectomy of two robotic camera holders, EndoAssist and AESOP: a pilot study.

OBJECTIVES: Robotic camera holders provide steady camera movement and view during laparoscopic surgery. We compared two such robots, EndoAssist and AESOP, by evaluating timed setup and surgical performance during laparoscopic radical prostatectomy (LRP). METHODS: We prospectively collected data for 20 patients undergoing LRP using either the EndoAssist or AESOP. AESOP was mounted to the surgical bed and controlled by an experienced assistant using a hand-held remote control. The EndoAssist device was placed over the patient's right shoulder. Its movements were executed by the surgeon using a head-mounted optical emitter with brief head movements detected by a sensor mounted atop the surgeon's video monitor. The robot setup time and LRP operative steps were timed and compared between the two cohorts. RESULTS: The time for robot setup favored AESOP over the EndoAssist (2.0 minutes versus 5.3 minutes, P = 0.001). The time for accomplishing vas deferens and seminal vesicle dissection favored the EndoAssist (23 minutes versus 33 minutes, P = 0.04). However, no statistically significant difference was found in the efficiency of task performance between the two robots in any of the other 11 steps measured. CONCLUSIONS: The EndoAssist appears to be equally efficient to the assistant-controlled AESOP robot with respect to surgical performance during LRP. The advantages of the EndoAssist include its accurate response and ability to provide the surgeon with complete control of the desired operative view without relying on an assistant. Its disadvantages include its large profile, lack of a table-mounted design, and the need for pedal activation. Additional modifications are needed to improve the efficiency and design of this novel robotic device further.

Humans↗

Resumption of motor vehicle operation in vasovagal fainters.

This study surveyed current practice patterns with respect to the manner by which cardiac arrhythmia specialists advise patients with vasovagal syncope regarding resumption of motor vehicle operation. Among 66 physician-respondents from 9 countries, 98% indicated that they rely on tilt-table testing to establish a diagnosis, and, if an effective treatment is found based on serial tilt-table testing, they recommend a 6- to 7-week symptom-free waiting period before advising return to driving.

Attitude of Health Personnel↗

Planning for subgroup analysis: a case study of treatment-marker interaction in metastatic colorectal cancer.

Subgroup analysis is a common secondary objective in clinical trials. In oncology where the outcome is often binary (such as tumor response) or time-to-event (such as survival), subgroup analysis can be formulated using an interaction term in logistic or proportional hazards regression models. We focus on a case study of planning a randomized trial in metastatic colorectal cancer possibly involving a treatment-marker interaction. We present a method that can be used to compute the power of interaction tests for a given sample size or to compute the necessary sample sizes for a desired level of power for the planned subgroup analysis. The principle idea is borrowed from analysis of variance and uses appropriate contrasts after a variance-stabilizing transformation. This method is conceptually and operationally simple. It can be applied to binary- or ordinal-marker measurements, and existing sample size tables or software can be used. The accuracy of the approximation is shown to be reasonable by simulation studies.

Biomarkers, Tumor↗

Merging claims databases with a tumor registry to evaluate variations in cancer mortality: results from a pilot study of 698 colorectal cancer patients treated at one hospital in the 1990s.

BACKGROUND: Prognostic models are essential for evaluating variations in cancer mortality statistics. While cancer stage is the most widely accepted and commonly used predictor of survival for cancer, electronic claims databases contain large amounts of information on cancer patients. Previous studies have used Medicare databases and tumor registry information from the Surveillance Epidemiology and End Results data sets to evaluate variations in outcomes for older cancer patients. We evaluated if similar analytic efforts could be carried out with readily available data sets for colorectal cancer patients of all ages who received care at a single hospital during the 1990s. METHODS: Hospital tumor registry and discharge claims data for patients at one mid-western hospital with surgically treated stage I-III colorectal cancer from 1990-1998 were used to model survival. Kaplan-Meier logrank tests and Cox proportional hazards models tested the statistical significance of demographic, operative, and clinicopathological factors as predictors of survival. Survival probabilities also were compared to U.S. population life table data to determine if survival deficits were larger for younger cancer patients. RESULTS: Of the 698 colorectal cancer patients, overall five-year survival probability was 65%, with a median follow-up of 44.7 months. Factors associated with higher relative risks of death included sociodemographic characteristics [female gender (1.5, 95% CI: 1.1-1.9), ages 70-79 years (1.7, 95% CI: 1.2-2.3), and > or = 80 years (3.3, 95% CI: 2.4-4.7) as compared to younger patients], clinical characteristics [moderate (1.5, 95% CI: 1.1-2.1) or severe (2.1, 95%: 1.4-3.2) comorbid illness, as compared to mild or no comorbid illnesses and emergency admission (2.1, 95% CI: 1.5-2.9)], pathological characteristics [positive surgical margins (3.5, 95% CI: 2.3-5.3): and higher cancer stage (stage II RR = 1.5, 95% CI = 1.1-2.2; stage III RR = 2.2, 95% CI = 1.5-3.2), as compared to stage I]. A comparison to the age- and gender-matched survival probabilities of the general population demonstrated similar deficits in survival for older patients (> or = 70 years) and younger patients (< 70 years). CONCLUSIONS: While cancer stage is a reliable predictor of survival, other sociodemographic and clinical data elements can improve the evaluation of expected survival rates for patients with surgically resectable colorectal cancers. To facilitate comparative interpretations of mortality data, consideration should be given to merging hospital discharge claims data sets with tumor registry information in a manner analogous to that which has been done for older cancer patients who are covered by the Medicare program.

Adult↗

Alignment with context dependent scoring function.

In the paper by Gambin et al. (2002) we introduced the model of contextual alignment of biological sequences. It is an extension of the classical alignment, in which the cost of a substitution depends on the surrounding symbols. Consequently, in this model the cost of transforming one sequence into another depends on the order of editing operations. In this paper, we strengthen some of our results which concern reconstructing (the representation of) all the orders of operations which yield this optimal cost. We also present a procedure to construct context-dependent substitution tables and discuss the distribution of scores of local contextual alignment, which is shown to follow the extreme value distribution in the gap-free, reduced context case. We also demonstrate a linear time algorithm to compute the optimal local and global alignment without gaps.

Algorithms↗

Selective gastric vagotomy and drainage for duodenal ulcer: a 10-13-year follow-up study.

From 1964 to 1968 selective gastric vagotomy (SGV) and drainage was performed in 174 patients. Of these, 105 patients were followed-up 10-13 years after operation; 56 were dead. Ulcers recurred in 18 patients. The cumulated recurrence rate after 13 years (life table method) was 15% (95% confidence limits: 8-23). The method for drainage was usually either a Heineke-Mikulicz or a Finney pyloroplasty. There was a significantly higher risk of ulcer recurrence in the group that underwent Heineke-Mikulicz drainage procedures. The incidence of dumping and diarrhea had not changed during a five-year follow-up period. Two patients were slightly anemic. No patient was iron-deficient. Apart from two recurrent ulcers, gastroscopic examinations in 36 patients revealed no major changes, and biopsy specimens showed slight to moderate chronic atrophic gastritis in most cases. Visick grading showed 77% of the ulcers in Grade I + II, 19% in Grade VI. It is concluded that SGV has no place in the elective treatment of duodenal ulcer. Two alternatives are suggested.

Adult↗

Primary shielding barriers for diagnostic x-ray facilities: a new model.

Traditional methods of diagnostic x-ray shielding design assume that the raw primary beam impinges directly on the structural barrier with attenuation by the patient and by the hardware in the x-ray beam (cassette, cassette holder, x-ray table) being ignored. Moreover, primary barrier calculations are done assuming a single, conservatively high value of the operating potential, rather than the lower kVp values more representative of clinical usage. This results in extreme conservatism, which is no longer defensible in light of the lowered dose limit to a member of the general public of 1 mSv y-1, which is equal in magnitude to natural background radiation (excluding radon). A shielding model is developed that accounts for attenuation of the primary beam prior to impinging on the structural barrier and which uses a workload which is distributed over a range of clinically realistic operating potentials. The resulting model is as simple to use as that, assuming a single value of the kVp. Sample calculations are performed and the results compared to those from more traditional shielding calculation methods.

Building Codes↗

Patients with a history of elevated prostate-specific antigen levels and negative transrectal US-guided quadrant or sextant biopsy results: value of MR imaging.

PURPOSE: To determine the role of magnetic resonance (MR) imaging performed with a combined endorectal body phased-array coil for patients with elevated prostate-specific antigen (PSA) levels or suspicious free-to-total PSA ratios in whom prior transrectal ultrasonographically (US) guided biopsy findings were negative for prostate cancer. MATERIALS AND METHODS: Forty-four patients with PSA levels greater than 4 ng/mL or free-to-total PSA ratios lower than 15% but negative biopsy findings were examined with T1- and T2-weighted MR imaging at 1.5 T with a combined endorectal body phased-array coil. All patients underwent digital rectal examination (DRE) and transrectal US. Thirty-eight patients underwent repeat biopsy after MR imaging. The accuracy of MR imaging for detection of prostate cancer was assessed prospectively. Retrospectively, MR imaging findings were correlated with individual biopsy site findings. MR imaging and biopsy results were correlated by using a cross table to calculate sensitivity, specificity, and positive predictive value (PPV). Retrospective analysis results were evaluated with receiver operating characteristic analysis. A P value of less than.05 indicated significance (chi(2) test according to Pearson). RESULTS: At prospective analysis, MR imaging had a sensitivity of 83% and a PPV of 50% for detection of prostate cancer; these values were 33% and 67%, respectively, for DRE and 33% and 57%, respectively, for transrectal US. At retrospective site-by-site analysis, MR imaging results did not correlate significantly with individual biopsy site findings (P =.126); sensitivity was 65% and PPV was 12%. CONCLUSION: In this patient population, MR imaging has higher sensitivity for detection of prostate cancer than DRE or transrectal US.

Aged↗

Clinical-pathologic correlation in Huntington's disease: a neuropsychological and computed tomography study.

To examine the premise that cognitive impairment in Huntington's disease (HD) is related to striatal degeneration, we determined those cognitive deficits most closely associated with linear CT indices of brain atrophy in HD. We systematically evaluated 60 drug-free HD patients who were judged to be in stages I (n = 34) or II (n = 26) of illness. All subjects underwent comprehensive neuropsychological assessment covering a broad spectrum of cognitive operations and standardized head CT imaging for determination of frontal horn (FH), intercaudate (CC), and outer-table (OT) distances. We grouped the cognitive test results, based on a principal-component factor analysis, to form factors 1 (complex psychomotor), 2 (verbal memory), 3 (visuospatial), and 4 (general knowledge). Factors 1 and 3 sharply discriminated between subjects in stages I and II of illness. Factors 1, 2, and 3 correlated strongly with CC/OT, an index of caudate atrophy, whereas only factor 2 correlated with FH/OT, an index of frontal atrophy. These data demonstrate that cognitive impairment is a clear-cut characteristic of early HD that is linked closely to the extent of caudate atrophy as measured by CT.

Adult↗

Chromatographic methods for analysis of aminoglycoside antibiotics.

Aminoglycosides are antimicrobial agents used frequently in treatment of human and animal diseases caused by aerobic, gram-negative bacteria. Because of the toxicity of these compounds, considerable effort has been attributed to analysis of aminoglycoside content in drug preparations, in serum and urine specimen in therapeutic drug monitoring, and in edible animal tissues in residue control. The present review emphasizes the analytical problems associated with aminoglycoside analysis. Screening methods based on microbiological and immunological procedures were briefly discussed. Gas chromatography and especially high-performance liquid chromatography appeared the most widely used chemical methods for the analysis of these compounds. Due to lack of volatility, chromophore, and hydrophility of aminoglycosides, most methods applied derivatization for enhancement of their chromatographic characteristics. The applicability and advantages of the various derivatization procedures were discussed in detail. A wide variety of detection methods, including mass spectrometry have been used. Packed column separation was generally used for gas chromatographic separation. In liquid chromatography, reversed phase, ion pair, ion exchange, and normal phase separation has been employed. Mass spectrometry, as a detection method, was discussed in detail. Extraction procedures from body fluids and tissues were emphasized. The performance and the operational conditions of the methods were described and detailed information of the data was provided also in table format.

Aminoglycosides↗