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Biomedical subjects

P Peduzzi

Publications and source records attributed to P Peduzzi.

At least 55 records · Page 3Linked to original sources
PubMed1984

Characteristics and outcome of medical nonadherers in the Veterans Administration Cooperative Study of Coronary Artery Surgery.

During a 7-year follow-up period in the Veterans Administration Study of Bypass Surgery, 75 (24%) of 311 medically assigned patients without left main disease "crossed over" to surgical treatment. Nineteen baseline, clinical, electrocardiographic and angiographic characteristics of the 75 crossover patients were compared with those of the 236 patients who adhered to medical treatment. At entry into the study, the crossover group contained more patients with severe angina than did the medical adherers group (p less than 0.05) and fewer patients with electrocardiographic evidence of previous myocardial infarction (p less than 0.05). Other entry characteristics were similar in distribution among those in the medical-adherer and crossover groups. The 2 major reasons for crossover were persistence or progression of angina, which occurred in 43 and 37% of the 75 crossover patients, respectively. There was no relation between progression of symptoms and angiographic progression of coronary narrowing. Thus, crossover was not determined by more severe coronary narrowing, but was associated with more severe symptoms and a lower incidence of infarction. The medically randomized patients who later underwent surgery (medical "nonadherers") experienced the same relief of angina 1 year after surgery as did the surgically randomized patients who initially received surgery (surgical "adherers"); however, their overall 7-year survival was lower (77% for medical nonadherers vs 83% for surgical adherers; difference not significant).

Clinical Trials as Topic↗
PubMed1982

The problem of attributing deaths of nonadherers: the VA coronary bypass experience.

In the VA Coronary Artery Surgery Study 84 of the 354 patients randomized to medical treatment had subsequent bypass surgery during a 6-year follow-up period. Of these, 18 had left main disease. The remaining 66 of 311 without left main disease crossed over to surgery at a constant rate of about 4% per year. The traditional assumption that patients who crossed over were at greater risk of dying than those who adhered was not substantiated by an analysis of known baseline risk factors. Crossover was not related to number of vessels diseased or other angiographic or noninvasive risk factors but was related to severity of angina which was not a risk factor in this study. These findings lend support to the validity of analyzing our survival data by the crossover method where nonadherers are counted as lost to follow-up at the time of treatment change.

Clinical Trials as Topic↗
PubMed1982

The Veterans Administration Cooperative Study of stable angina: current status.

The current status of the Veterans Administration Cooperative Study of the effect of surgery on survival in patients with stable angina is presented. The outcome in 686 adult males randomly allocated to medical or surgical treatment groups in 1972-1974 was studied in subgroups of patients classified by invasive (arteriographic) and noninvasive risk factors. In 91 patients with left main lesions reducing the luminal diameter 50% or more, surgery significantly improved survival in the two-thirds characterized as middle or high risk by four simple noninvasive predictors of prognosis (New York Heart Association functional classification III or IV, history of myocardial infarction, history of hypertension, and ST-segment depression on the resting baseline ECG as assessed on a centralized reading). Patients with three-vessel disease and no significant disease of the left main coronary artery also had better survival rates when treated surgically. However, this was statistically significant at 6 years only in the 10 hospitals in which the aggregate operative mortality was 3.3%. Patients without left main lesions were also categorized by four noninvasive predictors of risk. Categorizing such patients into roughly equal groups of high, middle, and low risk identified a high-risk group, in which surgery was associated with statistically improved survival, and low- and middle-risk groups in which it was not. The use of both invasive and noninvasive factors to assess risk in patients with chronic stable angina pectoris provided greater predictive power than either angiography or noninvasive factors alone.

Angina Pectoris↗
PubMed1982

Survival in subgroups of patients with left main coronary artery disease. Veterans Administration Cooperative Study of Surgery for Coronary Arterial Occlusive Disease.

This report presents the 42-month survival experience of 91 patients with a significant lesion of the left main coronary artery in the Veterans Administration Cooperative Study of Coronary Bypass Surgery. Survival in surgical patients was significantly better than that in the medical group (p = 0.016), even after adjustments were made for two important differences in baseline characteristics--duration of angina and high risk by angiographic criteria--between the two groups (p = 0.019). Subgroups based on severity of left main stenosis and on left ventricular (LV) function showed significant trends in favor of surgery in patients with more than 75% left main stenosis and in those with abnormal LV function. A similar but nonsignificant trend was seen in the two subgroups with 50-75% stenosis or with normal LV function. The surgical benefits were not significantly different between the categories of the subgroups defined separately by stenosis and LV function. Low-, middle- and high-risk subgroups based on four noninvasive clinical predictors also showed significantly improved survival with surgery in the high-risk group. The low-risk groups showed a slight, nonsignificant disadvantage with surgical treatment. These data support the view that patients with left main disease are not a homogeneous group. High- and low-risk subgroups with different outcomes and responses to treatment can be delineated by angiographic or clinical criteria. For most patients with left main disease, coronary artery bypass grafting offers improved longevity.

Adult↗
PubMed1981

Effect of bypass surgery on survival in patients in low- and high-risk subgroups delineated by the use of simple clinical variables.

A multivariate risk function was developed on data from all 508 medical patients in the Veterans Administration (VA) randomized study of coronary bypass surgery. The variables, in order of importance, were ST-segment depression on resting ECG, history of myocardial infarction, history of hypertension and New York Heart Association functional classification III or IV. These noninvasive variables have been reported to be risk factors in natural-history studies of coronary heart disease (CHD). Applying the risk function to medical and surgical patients of the 1972-1974 cohort yielded a 5-year probability of dying for each patient. Investigation of treatment effects in approximate terciles obtained by collapsing the probability distribution into low-, middle- and high-risk groups showed that surgery was beneficial for patients in the high-risk tercile even after removal of patients with left main coronary artery disease (17% surgical vs 34% medical mortality at 5 years; p less than 0.01). This finding was accentuated when patients in the 10 hospitals with the lowest operative mortality (3.3%) were compared. Mortality results in the low-risk tercile favored medical treatment (medical vs surgical mortality 7% vs 17%; p less than 0.05). The risk function predicted mortality well not only for te VA medical group, but also for an independent symptomatic CHD population from the University of Alabama arteriography registry. This report further delineates the advantages and limitations of coronary bypass surgery in CHD patients with chronic stable angina.

Coronary Artery Bypass↗
PubMed1980

A computer program for comparing survival experience of two groups after adjustment for relevant covariates.

A computer program is described which evaluates the difference in survival between two groups of patients based on the methods of Mantel [1] and Hankey and Myers [3]. Life table analysis is based on the stratification of prognostic variables. In addition, an adjusted survival curve is computed for one group of patients relative to the other group based on differences in the distribution of these variables. Plots of cumulative survival curves are optionally provided.

Computers↗
PubMed1979

A computer program for life table regression analysis with time dependent covariates.

This paper presents a computer program for analyzing time-dependent covariables in survival studies by the life table regression model described by Holford [3]. Basically, life table regression incorporates the elements of regression and the life table into a single model. Regression parameters are estimated by the method of maximum likelihood using the Newton-Raphson iterative procedure. The program provides two methods for testing hypotheses concerning regression coefficients, namely the standard normal deviate test and a Wald statistic based on the first and second derivatives of the log likelihood. Residual plots are provided to assess the fit of the model to the data.

Actuarial Analysis↗
PubMedDate not supplied

An evaluation of central laboratories in three VA cooperative studies.

We compared central laboratory with local determinations of key clinical measurements in three VA Cooperative Studies. Electrocardiographic evidence of new myocardial infarction was assessed in the study of Aspirin Therapy and Unstable Angina, ejection fraction measurement in the Coronary Artery Bypass Surgery Trial and lesion size in the Angioplasty Compared with Medicine (ACME) Trial. The findings in the Aspirin Trial indicated that central coding of all serial electrocardiograms in 1266 patients to detect new acute myocardial infarction by computer algorithm was not cost-effective when compared with the local investigator's diagnosis on the basis of a central Electrocardiographic Committee as the reference standard. In the other two trials, the contribution of the central laboratories was important because the assessments of the local investigators generally underestimated the degree of abnormality in the Bypass Trial and overestimated it in the ACME Trial. The VA results have clearly demonstrated two cases in which the decision for central evaluation was prudent, but one case in which it was not cost-effective. These equivocal findings indicate the need to evaluate the contribution of central laboratories when used as an adjunct to local determinations. Such evaluations may provide guidelines for decision-making in the design of future trials.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Informed consent for PSA screening: does it happen?

CONTEXT: Screening for prostate cancer with serum prostate-specific antigen (PSA) is controversial. Ideally, patients should be aware of the potential benefits and risks related to testing. PURPOSE: To assess whether patients remembered having PSA screening and to determine whether they recalled having a discussion with their primary care provider about the pros and cons of such testing. METHODS: A questionnaire was sent to patients who had PSA screening ordered by a primary care practitioner during a 2-month period at a university-affiliated Veterans Affairs medical center. Approximately 3 months after the PSA test was done, patients were asked about their baseline health as well as their knowledge of and attitudes toward screening with PSA and treatment for prostate cancer. RESULTS: The overall response rate was 197 out of 421 (46%) patients. Among 173 eligible respondents without prostate cancer, 53 (31%) were unaware that their physician had ordered a PSA test. Among the 120 patients who were aware of receiving the test, only 56 (47%) recalled having a discussion with their primary care provider about the risks and benefits of screening. Support for the test was more common among patients who recalled having PSA screening than those who did not recall having the test (91% vs. 70%, respectively; P = 0.003). CONCLUSIONS: Patients who have PSA screening often are unable to recall relevant facts about the test and may have no knowledge of its associated risks and benefits. The role and effectiveness of obtaining verbal informed consent for PSA screening should be re-evaluated.

Adult↗