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Biomedical subjects

S W Greenhouse

Publications and source records attributed to S W Greenhouse.

At least 19 recordsLinked to original sources
PubMed2000

Relationship of infarct artery patency and left ventricular ejection fraction to health-related quality of life after myocardial infarction: the GUSTO-I Angiographic Study experience.

BACKGROUND: Post-myocardial infarction global ejection fraction and infarct-related artery patency might be expected to be associated with health-related quality-of-life (HRQOL) outcomes, but this association has not been previously shown. The GUSTO-I Angiographic Study cohort 2-year follow-up afforded an examination of such potential relationships. METHODS AND RESULTS: A total of 1848 patients (87.7% response rate) who were enrolled in the GUSTO-I Angiographic Study were contacted for a telephone interview regarding their current HRQOL (physical function, psychological well-being, perceived health status, and social function) 2 years after MI. In multivariable models, left ventricular ejection fraction (EF) was significantly related to physical (P:=0.021) and social (P:=0.014) function, psychological well-being (P:=0.042), and perceived health status (P:=0.024). Infarct-related artery patency was not directly related to any HRQOL outcome. A decreasing EF was predictive of poorer outcomes in each HRQOL dimension. Men consistently had better outcomes in all HRQOL dimension with the exception of perceived health status. Increasing age was predictive of poorer outcomes in all dimensions of HRQOL except for psychological well-being where the inverse occurred; younger patients experienced greater depression, anxiety and worry than their older counterparts. The presence of comorbidities increased the likelihood of worse outcomes in all dimensions. CONCLUSIONS: This is the first study to demonstrate a significant relationship between EF and long-term HRQOL outcomes. This advantage in left ventricular function preservation should be added to the mortality advantage when considering the impact of treatment strategies for myocardial infarction.

Aged↗
PubMed1999

A selection of Mantel's contributions to laboratory research.

Nathan Mantel served as a statistician in the National Cancer Institute of the NIH for more than 25 years. During this period he was a consultant to many laboratory investigators, epidemiologists, clinicians and incidentally statisticians. These consultant activities in the design and analysis of data led to many of the research problems that he was engaged in as an independent investigator. Among these were many contributions to quantitative methods in laboratory research. This report discusses six such issues.

Epidemiology↗
PubMed1999

A randomized trial comparing primary angioplasty with a strategy of short-acting thrombolysis and immediate planned rescue angioplasty in acute myocardial infarction: the PACT trial. PACT investigators. Plasminogen-activator Angioplasty Compatibility Trial.

OBJECTIVES: The study evaluated the efficacy and safety of a short-acting reduced-dose fibrinolytic regimen to promote early infarct-related artery (IRA) patency during the inherent delay experienced by infarct patients referred for angioplasty as the principal recanalization modality. BACKGROUND: Previous approaches using long-acting, full-dose thrombolytic infusions rarely showed benefit, but they did increase adverse event rates. METHODS: Following aspirin and heparin, 606 patients were randomized to a 50-mg bolus of recombinant tissue-type plasminogen activator (rt-PA) (alpha half-life 4.5 min) or to placebo followed by immediate angiography with angioplasty if needed. The end points included patency rates on catheterization laboratory (cath lab) arrival, technical results when PTCA (percutaneous transluminal coronary angioplasty) was performed, complication rates, and left ventricular (LV) function by treatment assignment and time to restored patency following angioplasty. RESULTS: Patency on cath lab arrival was 61% with rt-PA (28% Thrombolysis in Myocardial Infarction trial [TIMI]-2, 33% TIMI-3), and 34% with placebo (19% TIMI-2, 15% TIMI-3) (p = 0.001). Rescue and primary PTCA restored TIMI-3 in closed arteries equally (77%, 79%). No differences were observed in stroke or major bleeding. Left ventricular function was similar in both treatment groups, but convalescent ejection fraction (EF) was highest with a patent IRA (TIMI-3) on cath lab arrival (62.4%) or when produced by angioplasty within an hour of bolus (62.5%). However, in 88% of angioplasties, the delay exceeded 1 h: convalescent EF 57.3%. CONCLUSIONS: Tailored thrombolytic regimens compatible with subsequent interventions lead to more frequent early recanalization (before cath arrival), which facilitates greater LV function preservation with no augmentation of adverse events.

Aged↗
PubMed1998

Extended mortality benefit of early postinfarction reperfusion. GUSTO-I Angiographic Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries Trial.

BACKGROUND: Reperfusion therapy for myocardial infarction, understood to reduce mortality by preserving left ventricular function, was initially expected to provide increasing benefits over time. Surprisingly, large controlled thrombolysis trials demonstrated maximum benefit at 4 to 6 weeks with no subsequent increased treatment advantage. Such studies, however, compared groups by assigned treatment, not physiological effectiveness. METHODS AND RESULTS: We calculated 2-year survival differences among 2431 myocardial infarction patients according to early infarct artery patency and outcome left ventricular ejection fraction using Kaplan-Meier curves. Hazard ratios for significant survival determinants were derived from Cox regression models. Two-year vital status (minimum, 688 days) was determined in 2375 patients (97.7%). A substantial mortality advantage for early complete reperfusion (Thrombolysis in Myocardial Infarction [TIMI] grade 3) and for preserved ejection fraction occurred beyond 30 days. The unadjusted hazard ratio for the TIMI 3 group compared with lesser grades at 30 days was 0.57 (95% confidence interval [CI], 0.35 to 0.94) and 30 days to > or = 688 days was 0.39 (95% CI, 0.22 to 0.69). Consequently, early TIMI 3 flow was associated with approximately a 3 patient per 100 mortality reduction the first month with an additional 5 lives per 100 from 30 days to 2 years. For ejection fraction >40% compared with < or = 40%, the unadjusted hazard ratio was 0.25 (95% CI, 0.16 to 0.37) at 30 days and 0.22 (95% CI, 0.15 to 0.33) after 30 days through 2 years (lives saved, approximately 9 and 11 per 100, respectively). CONCLUSIONS: Successful reperfusion and myocardial salvage produce significant mortality benefits that are amplified beyond the initial 30 days.

Female↗
PubMed1996

Increased left ventricular dysfunction in elderly patients despite successful thrombolysis: the GUSTO-I angiographic experience.

OBJECTIVE: This study sought to determine whether the recovery of regional and global left ventricular function is reduced in elderly patients despite successful thrombolytic therapy for acute myocardial infarction. Comparisons were made between elderly (> or = 75 years old, n = 47) and adult (< 75 years old, n = 434) patients enrolled in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) angiographic trial who underwent catheterization at 90 min and 5 to 7 days after thrombolysis and who had an open infarct-related artery with Thrombolysis in Myocardial Infarction (TIMI) grade 2 to 3 flow at both times. BACKGROUND: The morbidity and mortality of acute myocardial infarction is increased in elderly patients, presumably because of multiple adverse coexistent baseline variables. However, functional recovery after thrombolysis has not been characterized in the elderly. METHODS: Ejection fraction, end-systolic volume index, infarct and noninfarct zone contractile function (SD/chord) and infarct extent (number of chords) were determined. RESULTS: At 90 min, elderly patients with an open infarct-related artery had decreased infarct zone contractile function (-2.8 +/- 0.2 vs. -2.3 +/- 0.1 SD/chord in adults, p < or = 0.05) and a greater extent of injury (26.0 +/- 2.6 vs. 20.7 +/- 0.8 chords in adults, p < or = 0.05). At 5- to 7-day follow-up ventriculography, ejection fraction was reduced, and end-systolic volume index was significantly increased in elderly patients compared with adults. The severity of regional wall motion dysfunction in the infarct zone was also greater in the elderly than in adults at 5- to 7-day follow-up (-2.6 +/- 0.2 vs. -1.9 +/- 0.1 SD/chord, respectively, p < or = 0.005). Non-infarct zone contractile function at 90-min ventriculography was similar in both groups. Despite a patent infarct-related artery at 90-min, the 30-day mortality rate in the elderly remained elevated (17.8%) compared with that of adults (4%) (p < or = 0.0001). Elderly patients were predominantly female and had a higher prevalence of hypertension, multivessel coronary disease, previous infarction, anterior infarctions and later time to treatment (between 3 and 6 h) than adults. However, age > or = 75 years remained an independent determinant by multivariable regression analysis of 1-week postinfarction end-systolic volume index, regional left ventricular dysfunction (p = 0.02 and p < or = 0.008, respectively) and 30-day mortality (p < or = 0.0001). CONCLUSIONS: Elderly patients had increased damage in the infarct zone and had persistently increased mortality despite sustained infarct-related artery patency after successful thrombolysis. Although the causes are probably multifactorial, a more rapid progression of ischemic injury or a blunted postreperfusion recovery appears to contribute to the poorer outcomes in elderly patients.

Adult↗
PubMed1996

Angiographic findings and outcome in diabetic patients treated with thrombolytic therapy for acute myocardial infarction: the GUSTO-I experience.

OBJECTIVES: This study sought to determine whether diabetes mellitus, in the setting of thrombolysis for acute myocardial infarction, affects 1) early infarct-related artery patency and reocclusion rates; and 2) global and regional ventricular function indexes. We also sought to assess whether angiographic or baseline clinical variables, or both, can account for the known excess mortality after myocardial infarction in the diabetic population. BACKGROUND: Mortality after acute myocardial infarction in patients with diabetes is approximately twice that of nondiabetic patients. It is uncertain whether this difference in mortality is due to a lower rate of successful thrombolysis, increased reocclusion after successful thrombolysis, greater ventricular injury or a more adverse angiographic or clinical profile in diabetic patients. METHODS: Patency rates and global and regional left ventricular function were determined in patients enrolled in the GUSTO-I Angiographic Trial. Thirty-day mortality differences between those with and without diabetes were compared. RESULTS: The diabetic cohort had a significantly higher proportion of female and elderly patients, and they were more often hypertensive, came to the hospital later and had more congestive heart failure and a higher number of previous myocardial infarctions and bypass surgery procedures. Ninety-minute patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3) rates in patients with and without diabetes were 40.3% and 37.6%, respectively (p = 0.7). Reocclusion rates were 9.2% vs. 5.3% (p = 0.17). Ejection fraction at 90 min after thrombolysis was similar in diabetic and nondiabetic patients ([mean +/- SEM] 6.10 +/- 1.6% vs. 60.1 +/- 0.7%, p = 0.7), as was regional ventricular function (number of abnormal chords: 19.1 +/- 2.0 vs. 17.5 +/- 0.8, p = 0.3; SD/chord: -2.3 +/- 0.2 vs. -2.4 +/- 0.1, p = 0.6). Diabetic patients had less compensatory hyperkinesia in the noninfarct zone (SD/ chord: 1.3 +/- 0.2 vs. 1.7 +/- 0.1, p < or = 0.01). No significant difference in ventricular function was noted at 5- to 7-day follow-up. The 30-day mortality rate was 11.3% in diabetic versus 5.9% in nondiabetic patients (p < or = 0.0001). After adjustment for clinical and angiographic variables, diabetes remained an independent determinant of 30-day mortality (p = 0.02). CONCLUSIONS: Early (90-min) infarct-related artery patency as well as regional and global ventricular function do not differ between patients with and without diabetes after thrombolytic therapy, except for reduced compensatory hyperkinesia in the noninfarct zone among patients with diabetes. Diabetes remained an independent determinant of 30-day mortality after correction for clinical and angiographic variables.

Aged↗
PubMed1995

Biostatistical concepts and methods in the legal setting.

Biostatistical concepts and methods apply to various problems arising in actual U.S. legal cases. These involve: measures of association, assessing the potential effect of omitted variables and the Peters-Belson approach to regression. In particular, we present the inapplicability of Fisher's exact test in the case where the process determining the marginal sample sizes is not independent of the hypothesis under study by the 2 x 2 table. We adapt Cornfield's procedure to assess whether the omission of another factor could have contributed to a non-significant finding of the effect of the major factor under investigation. Finally, we demonstrate the relevance and utility of the Peters-Belson regression methodology to equal pay and promotion cases.

Biometry↗
PubMed1990

Some historical and methodological developments in early clinical trials at the National Institutes of Health.

This paper reviews five randomized clinical trials with unusual design or analysis features from institutes other than the National Cancer Institute or the National Heart, Lung and Blood Institute. These are: a Cooperative Study of Retrolental Fibroplasia sponsored by the National Institute of Neurological Diseases and Blindness; the Diabetic Retinopathy Study sponsored by the National Eye Institute; the University Group Diabetes Program sponsored by the National Institute of Arthritis and Metabolic Diseases; a Clinical Trial of the Extracranial to Intracranial Arterial Anastomosis (EC/IC bypass) by the National Institute of Neurological and Communicative Disorders and Stroke; and the Clinical Trial of Hereditary Angioedema by the National Institute of Allergy and Infectious Diseases.

Anastomosis, Surgical↗
PubMed1983

Early stopping for sequential restricted tests of binomial distributions.

In applications of restricted sequential procedures, the accumulating data can provide a strong indication that rejection of the null hypothesis is very unlikely if sampling is continued; however, trial termination with acceptance of the null hypothesis can require a large number of additional observations. Modifications of restricted sequential plans, based on the conditional probability of an inference contrary to that suggested by the data, are presented for trials with binary responses. The derived tests provide the potential for early stopping with acceptance of the null hypothesis and reduction of the expected stopping times. Properties of the stopping-time distributions are obtained exactly by considering the absorption probabilities of a binomial random walk on the lattice determined by the restricted sequential design. Relative efficiencies of the derived tests to the corresponding sequential probability ratio tests are presented, along with an example based on data from a clinical trial.

Statistics as Topic↗
PubMed1982

Jerome Cornfield's contributions to epidemiology.

This paper reviews the contributions Jerome Cornfield made to epidemiologic methodology. Section 2 discusses his development of the odds ratio obtained in a case-control study as an estimate of the relative risk of the disease under study. Section 3 presents Cornfield's introduction of the multiple logistic risk function as a smoothing function for data classified in a multi-way contingency table in order to determine the joint effects of several risk factors on the incidence of a disease. Section 4 gives a brief description of his work in the analysis of contingency tables. In Section 5, there is a summary of his views on a number of issues relating to the research, mostly case-control studies, on the relationship between smoking and lung cancer. The discussion in this section is selective and undoubtedly does not reflect all the important things he had to say on the subject. Finally, in Section 6, there is a discussion, based on only one of his papers on the subject, of some very significant thoughts on intervention studies in coronary disease.

Coronary Disease↗
PubMed1977

Gray scale measurement of biparietal diameter.

Fetal biparietal diameter measurements were obtained simultaneously by gray scale and bistable ultrasonography. The bistable presentation was measured from leading edge to leading edge, while the gray scale presentation was measured from leading point to leading point and middle to middle of the band of echoes defining the fetal head. Statistical analysis of 50 patients demonstrated good reproducibility of the biparietal diameter measurement by each method and intraobserver variation fell well within the acceptable range. In all but one patient differences in measurements between observers and measurement methods were trivial and of no clinical significance. In the patients in whom there was a statistically significant difference, the variability was from 1 to 2 mm with the exception of one patient in whom the variability was about 4 mm.

Cephalometry↗