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Biomedical subjects

E F Cook

Publications and source records attributed to E F Cook.

At least 109 records · Page 6Linked to original sources
PubMed1987

Evaluation of creatine kinase and creatine kinase-MB for diagnosing myocardial infarction. Clinical impact in the emergency room.

We prospectively studied the performance of emergency room strategies using a single sampling of total creatine kinase (CK) only and total CK with, if total CK levels were elevated, CK-MB levels in 639 patients with acute chest pain, including 386 patients who were admitted and 253 patients who were discharged. Acute myocardial infarction was diagnosed in 104 patients and excluded in 535. An elevated total CK level had a sensitivity of only 38% and specificity of only 80%, whereas a CK-MB level over 5% of an elevated total CK level had a sensitivity of only 34% and specificity of 88%. The sensitivities of both CK and CK-MB were higher in patients who arrived more than four hours after the onset of symptoms, and, in this population, the strategy using CK-MB performed significantly better than the strategy using total CK alone. Since a very positive CK-MB in a low-risk patient can greatly raise the probability of myocardial infarction, future strategies using CK-MB may have a role in selected subsets in determining which patients should not be sent home. However, the sensitivity of a single sampling of CK and CK-MB is too low for these assays to be used to exclude myocardial infarction in the emergency room or to be used as the rationale for deciding not to admit a patient.

Adult↗
PubMed1986

Long-term survival of more than 2,000 patients after coronary artery bypass grafting.

Among 2,004 patients who underwent their first coronary artery bypass graft operation between January 1970 and December 1980 without concomitant valve replacement or aneurysmectomy, life-table survival was 89% at 5 years and 80% at 8 years after surgery. In a multivariate Cox model analysis, the independent correlates of long-term survival were emergent operation with cardiogenic shock (multivariate mortality rate ratio [RR] = 14.0), use of a postoperative intraaortic balloon pump (RR = 3.9), ejection fraction less than 50% (RR = 2.4), preoperative history of congestive heart failure (RR = 2.2), cardiopulmonary bypass time (RR = 1.4 for each 30-minute increment), uncorrected mitral regurgitation (RR = 1.5 for each increment of angiographic gradation), left main coronary artery narrowing (RR = 1.7) and diabetes (RR = 1.6). After controlling for these factors, age, sex and the percentage of narrowings that were bypassed were not independent correlates of long-term survival.

Adult↗
PubMed1986

Value of noninvasive testing in adults with suspected aortic stenosis.

To determine the predictors of surgically correctable aortic stenosis in patients with systolic murmurs, 231 patients were evaluated. Five variables (carotid upstroke timing, carotid upstroke volume, aortic valve calcification on chest radiography, single or absent second heart sound, and a murmur with its maximal intensity at the right upper sternal border) were significant multivariate correlates. Two echocardiographic factors (a maximal aortic valve leaflet separation of 7 mm or less and hypertrophy of the posterior wall of the left ventricle to 12 mm or more) and one systolic time interval factor (a rate-corrected ejection time of more than 340 msec) added significant incremental information. When prospectively tested on an independent set of 86 patients with suspected aortic outflow obstruction, the combined clinical and noninvasive information correctly placed 10 patients (12 percent) into a low-risk group in which catheterization may not be indicated and 15 patients (17 percent) into a high-risk group in which it might be avoided or limited to coronary arteriography. This approach to predicting aortic stenosis deserves wider prospective testing.

Angina Pectoris↗
PubMed1986

Clinical response to coronary artery reoperations.

Repeat coronary artery bypass operations were performed on 112 patients at a university hospital between 1971 and 1981. When compared with patients who did poorly after a first operation but did not have repeat surgery, patients undergoing repeat surgery tended to be younger, to have a higher smoking rate and to have fewer prior myocardial infarctions, fewer diseased vessels and fewer lesions in distal vessels. At least 1 graft was occluded in 83% of patients undergoing reoperation, and a mean of 1.7 grafts were placed at reoperation. The operative mortality rate was 4%, with a follow-up mortality rate of 6% at a mean of 3.8 years. After reoperation, patients initially showed improvement to a mean specific activity scale class of 1.6, compared with 2.4 before the first operation and 2.7 before the second operation. The principal correlate of a better long-term symptomatic response compared with that in the period before the first operation was a lower serum cholesterol level, whereas the principal correlate of a better symptomatic response compared with that in the period just before the reoperation was the left ventricular ejection fraction. As recurrent symptoms after a first coronary artery operation become more prevalent, consideration of the selection factors and prognostic correlates of reoperation will become increasingly important.

Coronary Angiography↗
PubMed1985

Screening procedures in the asymptomatic adult. Comparison of physicians' recommendations, patients' desires, published guidelines, and actual practice.

To assess attitudes and practices regarding screening tests and preventive procedures, we surveyed 83 physicians in a hospital-based ambulatory care practice and compared their recommendations with the recommendations in published guidelines, the desires of 188 of their own patients, and the physicians' actual practice patterns on the surveyed patients. The surveyed physicians recommended screening procedures more frequently than the published guidelines in 48 situations and less frequently in 18 situations. Physicians at earlier levels of training tended to recommend more procedures than those who had completed training. Patients desired far more frequent screening than recommended either by their physicians or by the published guidelines. Physicians did not live up to their own recommendations for four of 14 procedures or to published guidelines for five of 14 procedures, with such failure occurring principally in situations where the test or procedure would normally be done personally by the physician.

Adolescent↗
PubMed1985

Case-control analysis of risk factors for presence of aortic stenosis in adults (age 50 years or older).

To analyze whether atherosclerotic risk factors, including systemic hypertension, an elevated serum cholesterol level, smoking and diabetes, were associated with the presence of aortic stenosis (AS) in adults, 105 adults who had AS without coronary artery disease (CAD) were compared with 110 control subjects who had other types of valvular disease, 170 control subjects who underwent catheterization and had neither valvular disease nor CAD, and 269 matched control subjects who underwent general surgery. When using each control group separately or in combination, no risk factor showed consistent evidence of a significant association with the development of AS. If the true magnitudes of these associations are of the order previously reported for the development of CAD, the power of our study for detecting statistical significance ranges from 56 to 99%. In a supplemental analysis, 45 cases with both AS and CAD did not have a higher prevalence of risk factors than cases without CAD. Although a weak association between atherosclerotic risk factors and AS cannot be excluded, any such association is unlikely to be as strong as for predicting CAD.

Aged↗
PubMed1985

Evaluation of prognostic classifications for patients with syncope.

To evaluate two published sets of prognostic classifications for patients with syncope, 176 consecutive patients who presented to an emergency room with syncope were studied. Although relatively few patients had cardiac syncope, these data confirmed their high one-year mortality. At the other extreme, it was also confirmed that patients who were 30 years of age or less or 70 years of age or less and had vasovagal/psychogenic syncope or syncope of unknown cause had a benign prognosis, with only two deaths in 225 patients in pooled data. However, these data did not confirm the previously reported prognoses for "medium-risk patients" or for patients with diagnosable noncardiovascular causes of syncope, largely because of differences in criteria for patient eligibility. It is concluded that available data allow over 70 percent of patients with syncope to be placed into either very-high or very-low-risk groups. However, further investigation, taking into account differences in patient selection criteria, will be required before accurate prognostic classifications can be derived for the nearly 30 percent of patients who do not fall into one of these extreme prognostic categories.

Adolescent↗
PubMed1985

Treatment of hypertension and its effect on cardiovascular risk factors: data from the Framingham Heart Study.

Analysis of the Framingham Heart Study experience between 1958 and 1970 showed a progressive increase in the rate of treatment and control of hypertension. With cross-sectional criteria to define diastolic hypertension, the treatment rate rose from 35% in 1958 through 1960 to 69% in 1968 through 1970 (p less than .001), and the treatment rate for sustained hypertension rose from 55% in 1958 through 1960 to 85% in 1968 through 1970 (p less than .001). Treated hypertensive subjects had higher pretreatment values of blood pressure but not of other cardiovascular risk factors than untreated hypertensive subjects. Treatment was more successful in controlling hypertension in later years (p less than .001), but in all years treatment reduced systolic and diastolic blood pressure without causing significant changes in mean serum cholesterol or glucose levels. In treated hypertensive subjects, the 8 year predicted risk of coronary heart disease declined by 2.3 events per 100 people compared with that in untreated hypertensive subjects (p less than .0001). The observed incidence of coronary heart disease was consistent with these predictions and suggested that treatment may be especially beneficial in subjects who have systolic blood pressures of 180 mm Hg or higher and who are treated for more than 2 successive years.

Adult↗
PubMed1985

Acute chest pain in the emergency room. Identification and examination of low-risk patients.

Clinical and laboratory data from 596 patients who came to an emergency room complaining of chest pain indicated that no single variable could identify low-risk patients as well as a normal ECG. A combination of three variables--sharp or stabbing pain, no history of angina or myocardial infarction, and pain with pleuritic or positional components or pain that was reproduced by palpation of the chest wall--defined a very-low-risk group in which ECGs did not add accuracy to the evaluation and were potentially misleading; however, only 48 patients (8%) fell into this category. Standard cardiac enzyme levels were of almost no use as an emergency room indicator of myocardial infarction. These findings emphasize the difficulty of identifying patients at low risk for myocardial infarction or unstable angina in the emergency room without consideration of many factors from the history, the physical examination, and the ECG.

Acute Disease↗
PubMed1984

On-site physician staffing in a community hospital intensive care unit. Impact on test and procedure use and on patient outcome.

To determine whether on-site physician staffing changed test and procedure use and improved patient outcome in a community hospital intensive care unit (ICU), we studied all ICU admissions for matched periods before and after the staffing change. Compared with the 463 year-1 patients, the 491 year-2 patients were no more likely to receive life-support interventions (respirators, dialysis, or pacemakers), but had substantially more monitoring interventions, such as pulmonary artery catheters (22% v 2%, P less than .0001) and arterial catheters (9% v 0%, P less than .0001). After controlling for factors that predicted death (age, mental status at time of admission, reason for ICU admission), year-2 patients were significantly more likely to survive the ICU and subsequent hospital stay (P = .01). Nearly all of the improvement of survival rate took place among patients with intermediate likelihoods of death; this improved survival rate persisted at the 12-month follow-up (P = .01).

Female↗
PubMed1984

Empiric comparison of multivariate analytic techniques: advantages and disadvantages of recursive partitioning analysis.

The recent ready availability of recursive partitioning analysis has provided medical investigators with an alternative to the usual parametric multivariate techniques. We believe that recursive partitioning analysis has several distinct advantages: it provides a simple and intuitive method for classifying subjects, it is designed to identify synergistic interactions among factors, it may identify nonlinear relationships with the endpoint, it provides a simple format for constructing homogeneous risk strata, and it considers prior probabilities and penalties for misclassification in its variable selection process. Conversely, parametric multivariate techniques have several advantages over recursive partitioning analysis: they may be better at finding predictive factors during the later stages of the selection process, they may be less subject to the problems of multiple testing and over-training, and they may be better able to account for the full predictive power of a continuous factor. Although neither type of technique is better in all situations, we believe that recursive partitioning analysis will often be the preferred multivariate method and is especially useful for identifying interaction terms that may then be included in parametric multivariate analyses.

Adult↗
PubMed1984

The selective impact of a cardiology data bank on physicians' therapeutic recommendations.

We asked the physicians and medical students caring for 60 patients with symptomatic coronary artery disease, immediately after reviewing cardiac catheterization data, to choose medical or surgical therapy and to estimate prognosis one and three years after either therapy. The next day, each participant was given prognostic estimates generated from a large coronary artery disease data bank and again asked to estimate prognosis and choose therapy. Participants unanimously chose medicine for 20 patients (Group I) and surgery for 21 patients (Group III). For 19 patients (Group II), participants were divided on their choice of therapy. After seeing data bank estimates, participants rarely changed recommendations for Group I or Group III, but changed ten percent (9/90, p less than 0.01) of their Group II recommendations. Changes of recommendations by far (9/12, p = 0.02) favored medicine, causing the majority recommendation to change to medicine for two Group II patients. Therapeutic recommendations were guided mostly by pathoanatomy and the chance of improving medical regimens. Computer-generated prognostic data selectively influenced choices among the Group II cases where recommendations had been divided, resulting in changes toward less costly therapy.

Cardiac Catheterization↗
PubMed1984

The decline in ischemic heart disease mortality rates. An analysis of the comparative effects of medical interventions and changes in lifestyle.

Using reasonable assumptions gathered from the published literature, we estimated that more than half of the decline in ischemic heart disease mortality between 1968 and 1976 was related to changes in lifestyle, specifically to reductions in serum cholesterol levels and cigarette smoking. In comparison, about 40% of the decline can be directly attributed to specific medical treatment of clinical ischemic heart disease and hypertension being the leading estimated contributors. Because many of these interventions have not yet been applied to their maximum potential, a continued decline in mortality rates might be anticipated in the coming decades. However, the relative costs of these medical interventions and lifestyle changes and the extent to which they interact with each other must be considered before an optimal national health strategy can be derived.

Arrhythmias, Cardiac↗
PubMed1984

Medical consequences of missed appointments.

"No-show" patients (n = 100) were matched by age and number of appointments scheduled in a six-month period with 100 control patients who kept an appointment. No-show patients were less likely than control patients to have chronic medical problems (78% v 94%, respectively) and to be receiving long-term medications (58% v 73%, respectively) at the time of entry into this study. At follow-up at 29 to 51 weeks, no-show and control patients did not differ significantly in the development of new medical problems or the exacerbation of old medical problems either before or after controlling for differences in baseline health status. No hospitalizations or deaths could be directly attributed to a missed appointment. No-show patients were more likely than control patients to say they felt better at follow-up (42% v 26%, respectively). No-show patients may believe the benefit of keeping an appointment is not worth the inconvenience or expense. We suggest that physicians should carefully justify the need for a follow-up visit and consider negotiating follow-up schedules with their patients.

Adolescent↗
PubMed1983

Survival after cardiopulmonary resuscitation in the hospital.

Little is known about prognostic factors that determine outcomes after in-hospital cardiopulmonary resuscitation. We studied prospectively 294 consecutive patients who were resuscitated in a university teaching hospital. Forty-one patients (14 per cent) were discharged from the hospital; three quarters of them were still alive six months later. A multivariate analysis revealed that pneumonia, hypotension, renal failure, cancer, and a homebound life style before hospitalization were significantly associated with in-hospital mortality (P less than 0.05). None of the 58 patients with pneumonia and none of the 179 in whom resuscitation took longer than 30 minutes survived to be discharged. On the other hand, fully 42 per cent of the patients who survived for 24 hours after resuscitation left the hospital. At the time of discharge from the hospital and again six months later, 93 per cent of the survivors were mentally intact. Although depression was generally present at the time of discharge, it tended to resolve subsequently. However, all patients reported some decrease in functional capacity, often attributed to fear. This persisted at six months after discharge. Age alone did not appear to influence the prognosis for survival after cardiopulmonary resuscitation or the adjustment to chronic illness after discharge from the hospital.

Adolescent↗
PubMed1983

The changing "natural history" of symptomatic coronary artery disease: basis versus bias.

In contrast to the 20 to 30% reduction in ischemic heart disease mortality that has been demonstrated by national mortality statistics and by several randomized controlled trials, an uncritical reading of recent "natural history" studies suggests far greater improvements in the survival of symptomatic coronary patients. Although the intrinsic accuracy of such natural history studies is not questioned, attempts to compare patients from different studies and different eras may greatly overestimate the true improvement in natural history because of at least 3 biases in the selection of cases from the spectrum of diseased patients. Because of lead-time bias, patients who are diagnosed earlier live longer regardless of whether interventions are efficacious. Because of referral bias, current patients may have symptoms or anatomy that place them at a different stage of severity than patients who were chosen for earlier studies. Because of incidence-prevalence bias, prevalence studies will be over-represented with survivors of previous incidence cohorts who have slower-progressing disease. We suggest that all natural history studies be carefully scrutinized for such biases before they are compared with each other.

Analysis of Variance↗