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At least 19 recordsLinked to original sources

Preoperative MRI predicts outcome of temporal lobectomy: an actuarial analysis.

We used actuarial methods to study outcome after temporal lobectomy in 135 consecutive patients classified into subgroups according to preoperative MRI findings. Sixty months after surgery, 69% of patients with foreign tissue lesions, 50% with hippocampal sclerosis, and 21% with normal MRIs had no postoperative seizures. An eventual seizure-free state of 2 years or more, whether the patient was seizure-free since surgery or not, was achieved by 80% of patients with foreign tissue lesions, 62% of those with hippocampal sclerosis, and 36% of those with normal MRIs. Outcome was worse in those with normal MRIs than in the other two groups. Early postoperative seizures with later remission (the "running down" phenomenon) occurred in all groups. Late seizure recurrence was present only in the hippocampal sclerosis group. These data show that preoperative MRI is a useful predictor of outcome and that actuarial analysis provides insight into different longitudinal patterns of outcome in MRI subgroups. This information can now be used in preoperative counseling.

Actuarial Analysis↗

[Actuarial analysis of time-failure data and its rrelevance for interpretation of results. Audit of the journal "Strahlentherapie und Onkologie" (Radiotherapy and Oncology)].

BACKGROUND: The statistical quality of the contributions to "Strahlentherapie und Onkologie" is assessed, aiming for improvement of the journal and consequently its impact factor. MATERIAL AND METHODS: All 181 articles published during 1998 and 1999 in the categories "review", "original contribution", and "short communication" were analyzed concerning actuarial analysis of time-failure data. RESULT: One hundred and twenty-three publications without time-failure data were excluded from analysis. Forty-five of the remaining 58 publications with time-failure data were evaluated actuarially. This corresponds to 78% (95% confidence interval: 64 to 88%) of papers, in which data were adequately analyzed. Complications were reported in 16 of 58 papers, but in only 3 cases actuarially. The number of patients at risk during the course of follow-up was documented adequately in 22 of the 45 publications with actuarial analysis. CONCLUSION: Authors, peer reviewers, and editors could contribute to improve the quality of the journal by setting value on acturial analysis of time-failure data.

Actuarial Analysis↗

Revision rate after artificial urinary sphincter implantation for incontinence after radical prostatectomy: actuarial analysis.

PURPOSE: We determined the actuarial revision rate for artificial urinary sphincters implanted in patients who were incontinent after radical prostatectomy. MATERIALS AND METHODS: We reviewed the records of 70 consecutive patients who were incontinent after radical prostatectomy and who underwent primary artificial urinary sphincter implantation at the University of Michigan between 1984 and 1999. Questionnaires were mailed to all patients with an indwelling device, and telephone calls were placed to those who did not respond to the mailing. Information about surgical revision and current continence status was obtained from chart review and questionnaire response. The Kaplan-Meier curves for actuarial freedom from operative revision were constructed. RESULTS: Of the 66 patients with available postoperative data 24 (36%) required reoperation at a mean followup of 41 months. The 5-year actuarial rate for freedom from any operative revision was 50%, and the corresponding rate for cuff revision was 60%. A single operative revision did not predispose the patient to further revision. Questionnaire data indicated a continence rate of 80% (range 0 to 2 pads). CONCLUSIONS: Approximately half of the patients who were incontinent after radical prostatectomy may expect to undergo operative revision within 5 years after artificial urinary sphincter implantation. Despite this high reoperation rate, an excellent level of continence is maintained.

Actuarial Analysis↗

Assessing the benefit of biological valve prostheses: cumulative incidence (actual) vs. Kaplan-Meier (actuarial) analysis.

OBJECTIVE: The standard method of analysing structural valve degeneration (SVD) of biological prostheses is the Kaplan-Meier method. In order to assess SVD with regard to competing risks (e.g. death particularly in elderly patients) cumulative incidence (actual analysis) was compared to Kaplan-Meier (actuarial analysis). METHODS: We retrospectively analysed 257 patients older than 60 years, who underwent mitral valve replacement with different biological prostheses between 1974 and 2000. Reoperation-free survival was determined, both according to Kaplan-Meier and cumulative incidence analysis. RESULTS: For the total group of patients older than 60 years, the 10- and 15-year freedom from reoperation was 79+/-5 and 55+/-8%, respectively, according to Kaplan-Meier and 90+/-2 and 83+/-3% according to cumulative incidence analysis. For patients older than 65 years of age (n=170), Kaplan-Meier analysis revealed 85+/-7% freedom from reoperation at 10 years vs. 94+/-3% according to cumulative incidence analysis. For those between 60 and 65 years of age (n=87), Kaplan-Meier freedom from reoperation was 76+/-7% at 10 years and 48+/-9% at 15 years vs. 86+/-4 and 75+/-5% according to cumulative incidence analysis. CONCLUSIONS: Kaplan-Meier analysis overestimates the 10- and 15-year risk of SVD compared to cumulative incidence analysis, thus underestimating the benefit of biological valve replacement. Cumulative incidence analysis may lead to a more complete evaluation of risk and benefit and thus better patient management.

Aged↗

Closed mitral valvotomy: actuarial analysis of results in 654 patients over 12 years and analysis of preoperative predictors of long-term survival.

The records of 654 patients with mitral stenosis who underwent closed mitral valvotomy over a 12-year period were submitted to actuarial analysis. This revealed a low (2.97%) operative mortality. At 12 years, the overall cumulative proportion surviving was 78%; 47% of patients survived without reoperation. The usual clinical indicators of suitability for closed valvotomy were successful in predicting improved survival. The surgeon's assessment of the suitability of the valve correlated well with outcome. Valvotomy during pregnancy was associated with a good long-term outlook. The presence of pulmonary hypertension and atrial fibrillation did not alter survival significantly. Sex ane age were not associated with adverse prognosis. We conclude that closed mitral valvotomy still has a place in the management of mobile mitral stenosis, particularly in areas where there is a high incidence of rheumatic heart disease and a large number of young patients have mobile mitral stenosis.

Actuarial Analysis↗

Early and late results of coronary artery bypass after failed angioplasty. Actuarial analysis of late cardiac events and comparison with initially successful angioplasty.

We reviewed the results of early (less than 24 hours) coronary artery bypass after unsuccessful percutaneous coronary artery angioplasty in 146 patients treated between October 1979 and July 1986. Overall operative mortality was 2.7%, and risk was significantly increased among patients with hemodynamic instability and new occlusion or further narrowing of the dilated vessel (3.8 versus 0%, p less than 0.05). Actuarial analysis was used to compute the rates of cardiac events during the follow-up interval, and event rates were also estimated in a comparison group of 776 patients who had successful first-time PTCA during the same time period. At a follow-up interval of 5 years, the cumulative risks of recurrence of angina and need for an additional procedure (bypass or angioplasty) were significantly (p less than 0.05) lower for patients who had undergone bypass than for those who had successful angioplasty (angina 21% versus 56%, PTCA 2% versus 21%, CAB 6% versus 16%). Cumulative risks of myocardial infarction and death were 4% versus 9% and 6% versus 9% in the two groups. The differences between late outcomes in the bypass and angioplasty groups persisted when patients were stratified into cohorts with single-vessel and multivessel disease, and the highest late event rate occurred in patients in the angioplasty group who had incomplete revascularization. The difference in late events after bypass or angioplasty was greatest during the first year. These late data should be considered when the mode of revascularization (bypass or angioplasty) is selected for symptomatic patients, especially those with multivessel disease.

Actuarial Analysis↗

Actuarial analysis of the occurrence of remissions following thymectomy for myasthenia gravis in 400 patients.

The role of thymectomy in the treatment of myasthenia gravis (MG) was analysed in 400 patients affected with generalised MG operated on between 1974-83, and prospectively followed up for five years after surgery. The occurrence of stable remission (SR) (that is, complete clinical drug-free remission that remains stable for all the subsequent follow up) was the endpoint of survival analyses and the distribution of SR time (SRT, that is, the interval from thymectomy to the occurrence of SR) was assessed by actuarial and Cox multivariate analyses. SRT distribution after surgery showed a slow progressive increase of cumulative SR rate that could both be ascribed to a delayed effect of thymectomy as well as reflect the natural history of MG, itself characterised by an increasing probability of spontaneous remission with time. SRT distribution was similar after stratification for all variables studied except when patients without thymoma were stratified for the need for immunosuppressive treatment in addition to thymectomy. Patients without thymoma who did not require additional immunosuppressive therapy (n = 130) had the highest SR rate occurring in the two years after thymectomy, and differed from patients treated with immunosuppressive drugs who showed the highest SR rate five years after surgery. Actuarial analysis has therefore identified a subgroup of patients where SR, occurring in the first years after surgery, is more likely to be ascribed to thymectomy than merely reflect the natural course of the disease.

Actuarial Analysis↗

Single-stage surgery for cholesteatoma: an actuarial analysis.

Single-stage surgery was used for 215 operations for cholesteatoma. The results were analyzed using months at risk (actuarial) statistics. The methods of data collection and of creating a life-table for cholesteatoma follow-up are described. Ninety-one canal-down procedures are compared with 124 canal-up procedures as to the recidivism rate as well as hearing results. The actuarial tables showed a 45% cumulative success rate for canal-up procedures versus a 90% rate for canal-down operations. The successful canal-up procedures demonstrated slightly better hearing results, however. These success rates seemed to be comparable to those using planned staged surgery. It was concluded that, if single-stage canal-up procedures were used with larger mastoids and canal-down procedures with smaller mastoids, 80% of patients could be controlled without either residual or recurrent disease appearing. For the others, it was felt safe to wait for the disease to reappear rather than to do planned two-stage procedures for all patients. It was further urged that actuarial statistics be employed when reporting the results of surgery for cholesteatoma.

Actuarial Analysis↗

Are we selecting the right patients for treatment of localized prostate cancer? Results of an actuarial analysis.

OBJECTIVES: To determine our accuracy in selecting patients with at least a 10-year life expectancy for aggressive treatment of localized prostate cancer. METHODS: The medical records of 261 consecutive patients who underwent radical retropubic prostatectomy were submitted to the actuarial division of American General Life and Accident Insurance Company (AGLA) for estimation of life expectancy, excluding the diagnosis of prostate cancer. Survival curves were generated from predicted individual survivals. In patients with less than a 10-year life expectancy, AGLA provided us with the basis for assigning suboptimal survival rates. RESULTS: The mean life expectancy for the group was 15.2 years. Two hundred ten men (80%) were projected to have a life expectancy of more than 10 years, including 27 of 55 (49%) and 4 of 8 (50%) men who were older than or equal to 70 and 75 years of age, respectively. Coronary artery disease and diabetes mellitus were the most common coexisting medical conditions that adversely affected risk as single disease entities. CONCLUSIONS: Although clinicians do not estimate life expectancy with the scientific exactitude of an actuary, the ability to assess the patient in person and assimilate pertinent medical information in a less rigid format yields similar results. Selection of men for definitive treatment of localized prostate cancer should be based on the inherent aggressiveness of the disease and the health of the individual and should not be limited by specific age cutoffs. Populations of men undergoing radical prostatectomy are younger and healthier than those in reported series of watchful waiting for prostate cancer.

Actuarial Analysis↗

Actual versus actuarial analysis for cardiac valve complications: the problem of competing risks.

Methods for analyzing rates of events such as heart valve failure following surgery are important for comparing different techniques and devices; however, in patients undergoing major surgery, other risks such as mortality compete with the risk of heart valve failure to determine each patient's final outcome. When multiple, mutually exclusive endpoints are possible, a situation known to statisticians as a competing risks problem arises. No single statistical technique that is currently available provides an entirely satisfactory solution to this problem. We argue that in order for valve failure incidences to be useful clinically, the overall patient outcome milieu from which these failures arise must be considered. In this article, we review recent work in the area of competing-risks analysis as it pertains to heart valve surgery outcome.

Actuarial Analysis↗

Actuarial analysis of reoperation in patients undergoing open mitral commissurotomy for mitral stenosis.

Reoperation is one of the most seriously problematical events in postoperative follow-up of patients undergoing open mitral commissurotomy (OMC) for mitral stenosis. In 217 patients with pure mitral stenosis, even when associated with severe subvalvular changes, the actuarial rate of freedom from reoperation was 94% 12 years after OMC. In contrast, in 85 patients with MS combined with regurgitation, the rate was 66%. In postoperative management of patients undergoing OMC, it is mandatory to know preoperative anatomical findings of the stenosed mitral valve.

Actuarial Analysis↗

Actuarial analysis of a uniform and reliable preservation method for viable heart valve allografts.

CryoLife has developed a method for cryopreserving allograft heart valves for transplantation. Since 1984, 6,907 valves have been processed and 4,216 transplanted. Documentation was available on 2,647 transplants, 11 of which were removed for structural deterioration and 13, for nonstructural deterioration. At the end of 35 months, actuarial survival was 99.17% and the estimated freedom from reoperation, 97.16%. There have been no reports of thromboembolism or valve-related death.

Actuarial Analysis↗