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Biomedical subjects

D B Pryor

Publications and source records attributed to D B Pryor.

At least 109 records · Page 6Linked to original sources
PubMed1983

An improving prognosis over time in medically treated patients with coronary artery disease.

The national mortality rate from coronary heart disease has decreased during the past decade, for reasons that are not yet clear. The mortality rate and the total number of cardiovascular events both decreased during the last 10 years in 1,911 medically treated patients with significant coronary artery disease. This decrease cannot be explained by less sick patients being referred for evaluation. This study suggests that at least part of the decrease in coronary heart disease mortality observed nationally is occurring in patients with established coronary disease.

Coronary Disease↗
PubMed1983

Estimating the likelihood of significant coronary artery disease.

Among 23 clinical characteristics examined in 3,627 consecutive, symptomatic patients referred for cardiac catheterization between 1969 and 1979, nine were found to be important for estimating the likelihood a patient had significant coronary artery disease. A model using these characteristics accurately estimated the likelihood of disease when applied prospectively to 1,811 patients referred since 1979 and when used to estimate the prevalence of disease in subgroups reported in the literature. Since accurate estimates of the likelihood of significant disease that are based on clinical characteristics are reproducible, they should be used in interpreting the results of additional noninvasive tests and in quantitating the added diagnostic value.

Adult↗
PubMed1983

Prognostic value of ventricular arrhythmias associated with treadmill exercise testing in patients studied with cardiac catheterization for suspected ischemic heart disease.

The prognostic information provided by ventricular arrhythmias associated with treadmill exercise testing was evaluated in 1,293 consecutive nonsurgically treated patients undergoing an exercise test within 6 weeks of cardiac catheterization. The 236 patients with simple ventricular arrhythmias (at least one premature ventricular complex, but without paired complexes or ventricular tachycardia) had a higher prevalence of significant coronary artery disease (57 versus 44%), three vessel disease (31 versus 17%) and abnormal left ventricular function (43 versus 24%) than did patients without ventricular arrhythmias. Patients with paired complexes or ventricular tachycardia had an even higher prevalence of significant coronary artery disease (75%), three vessel disease (39%) and abnormal left ventricular function (54%). In the 620 patients with significant coronary artery disease, patients with paired complexes or ventricular tachycardia had a lower 3 year survival rate (75%) than did patients with simple ventricular arrhythmias (83%) and patients with no ventricular arrhythmias (90%). Ventricular arrhythmias were found to add independent prognostic information to the noninvasive evaluation, including history, physical examination, chest roentgenogram, electrocardiogram and other exercise test variables (p = 0.03). Ventricular arrhythmias made no independent contribution once the cardiac catheterization data were known. In patients without significant coronary artery disease, no relation between ventricular arrhythmias and survival was found.

Arrhythmias, Cardiac↗
PubMed1983

Outcome in one-vessel coronary artery disease.

We analyzed the clinical outcomes in 688 patients with isolated stenosis of one major coronary artery. The survival rate among patients with disease of the right coronary artery (RCA) was higher than that among patients with left anterior descending (LAD) or left circumflex coronary artery (LCA) disease. The survival rate among patients in all three anatomic subgroups exceeded 90% at 5 years. The presence of a lesion proximal to the first septal perforator of the LAD was associated with decreased survival compared with the presence of a more distal lesion. For the entire group of one-vessel disease patients, total ischemic events (death and nonfatal infarction) occurred at similar rates regardless of the anatomic location of the lesion. Left ventricular ejection fraction was the baseline descriptor most strongly associated with survival, and the characteristics of the angina had the strongest relationship with nonfatal myocardial infarction. No differences in survival or total cardiac event rates were found with surgical or nonsurgical therapy. The relief of angina was superior with surgical therapy, although the majority of nonsurgically treated patients had significant relief of angina. The survival rate of patients with one-vessel coronary disease is excellent, and the risk of nonfatal infarction is low. Clinical strategies for the care of these patients must consider the long-term clinical course of one-vessel coronary disease.

Angina Pectoris↗
PubMed1983

The prognosis for patients with new-onset angina who have undergone cardiac catheterization.

We investigated the prognostic significance of new-onset angina in patients in whom coronary anatomic characteristics were known. New onset angina was defined as angina of less than 3 months duration. Consecutive patients (n = 1727) with significant coronary artery disease (diagnosed at cardiac catheterization) and who had not had a prior myocardial infarction or congestive heart failure were studied. In patients with new-onset angina (n = 329) there was a higher incidence of single-vessel disease (43% vs 27%) and a lower incidence of triple-vessel (23% vs 35%) and left main artery (5% vs 10%) disease compared with patients with chronic angina (n = 1398). Patients were classified by the presence or absence of preinfarction angina (severe and prolonged angina at rest requiring hospitalization to rule out myocardial infarction). In patients treated without surgery and who did not have preinfarction angina, survival at 1 year was 97% for patients with new-onset angina and 98% for those with chronic angina (p = .27). Among patients not treated surgically who did not have preinfarction angina, at 1 year 16% with new-onset angina and 7% with chronic angina had suffered a cardiac event (nonfatal myocardial infarction or death, p = .006). In patients treated surgically who did not have preinfarction angina, survival at 1 year was 96% both for those with new-onset angina and those with chronic angina (p = .99). The risk of an event in patients treated surgically at 1 year was not statistically different in patients with new-onset angina and those with chronic angina (12% vs 11%, p = .27). Survival and event-free rates were lower in patients with preinfarction angina than in patients who did not have it.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1983

Natural history of cerebral complications of coronary artery bypass graft surgery.

We reviewed 1,669 patients who survived coronary artery bypass graft surgery between 1969 and 1981. A total of 75 cerebral complications were identified, including (1) altered mental state, (2) stroke, and (3) seizure in 64 patients (3.8%). Altered mental state (delirium, hypoxic-metabolic encephalopathy) occurred in 57 (3.4%). Postoperative arrhythmias were associated with an increased risk of altered mental state. Cerebral infarction occurred in 13 (0.8%). Patients who suffered stroke had a higher occurrence of carotid bruits and history of peripheral vascular disease. Seizures occurred in five patients (0.3%). Mortality in patients with a neurologic complication was 29%.

Brain Diseases↗
PubMed1983

Adverse effects of nifedipine therapy on hypertrophic obstructive cardiomyopathy.

A 62-year-old man with obstructive hypertrophic cardiomyopathy was given sublingual nifedipine, 10 mg, during invasive hemodynamic monitoring. After 15 minutes, his left ventricular outflow gradient increased from 22 to 80 mm Hg while arterial pressure fell from 152/70 to 122/64 mm Hg. Left ventricular end-diastolic pressure increased from 15 to 22 mm Hg. These adverse hemodynamic responses may have been a result of vasodilation of the peripheral circulation induced by nifedipine. Thus, some patients with hypertrophic obstructive cardiomyopathy may develop serious hemodynamic compromise when treated with nifedipine.

Atrial Fibrillation↗
PubMed1983

Early discharge after acute myocardial infarction.

Approximately 50% of patients hospitalized with acute myocardial infarction have an uncomplicated course and an excellent prognosis. To be considered as having an uncomplicated course, patients should not have ventricular tachycardia or fibrillation, second or third degree atrioventricular block, pulmonary edema, cardiogenic shock, infarct extension, persistent hypotension, sinus tachycardia, or sustained supraventricular tachycardia occurring within the first 4 days of hospitalization. Patients with recurrent angina in the postinfarction period may also be at increased risk. Early and rapidly progressive rehabilitation programs permit the safe discharge of patients with an uncomplicated course after 7 days. Functional exercise testing before, or soon after, early discharge may identify high-risk patients and alter their management.

Follow-Up Studies↗
PubMed1982

Evaluating the yield of medical tests.

A method is presented for evaluating the amount of information a medical test provides about individual patients. Emphasis is placed on the role of a test in the evaluation of patients with a chronic disease. In this context, the yield of a test is best interpreted by analyzing the prognostic information it furnishes. Information from the history, physical examination, and routine procedures should be used in assessing the yield of a new test. As an example, the method is applied to the use of the treadmill exercise test in evaluating the prognosis of patients with suspected coronary artery disease. The treadmill test is shown to provide surprisingly little prognostic information beyond that obtained from basic clinical measurements.

Catheterization↗
PubMed1982

Prognostic implications of ventricular arrhythmias during 24 hour ambulatory monitoring in patients undergoing cardiac catheterization for coronary artery disease.

The prognostic importance of ventricular arrhythmias detected during 24 hour ambulatory monitoring was evaluated in 395 patients with and 260 patients without significant coronary artery disease. Ventricular arrhythmias were found to be strongly related to abnormal left ventricular function. A modification of the Lown grading system (ventricular arrhythmia score) was the most useful scheme for classifying ventricular arrhythmias according to prognostic importance. When only noninvasive characteristics were considered, the score contributed independent prognostic information, and the complexity of ventricular arrhythmias as measured by this score was inversely related to survival. However, when invasive measurements were included, the ventricular arrhythmia score did not contribute independent prognostic information. Furthermore, ejection fraction was more useful than the ventricular arrhythmia score in identifying patients at high risk of sudden death.

Adrenergic beta-Antagonists↗
PubMed1982

Problems and advantages of an observational data base approach to evaluating the effect of therapy on outcome.

In this report, we summarize the strengths and problems of an observational data base approach to evaluating therapy and studying patient outcomes in long-term chronic disease. Because this approach includes a greater spectrum of patients than randomized clinical trials, it offers a definite advantage with regard to the elucidation of prognostic factors and the application of results to specific patients. The major difficulty with the observational data base approach is that the important prognostic factors must be known for treatment comparisons to be valid. Both the observational data base and randomized trial approaches are susceptible to criticism because the multiple comparisons and multiple experiments usually involved make the results of any one study not definitive. Either approach is useful in generating or confirming a hypothesis about particular subgroups. Regardless of the method used, proof that a particular therapy increases survival in any group or subgroup of patients with coronary artery disease usually requires confirmation by multiple studies. Finally, observational data base approach, because it capitalizes on data generated and paid for in the patient care process, offers the most feasible approach for evaluating whether changes in prognosis are occurring over time and whether such changes are independent of the mix of the patient population.

Clinical Trials as Topic↗
PubMedDate not supplied

Regression modelling strategies for improved prognostic prediction.

Regression models such as the Cox proportional hazards model have had increasing use in modelling and estimating the prognosis of patients with a variety of diseases. Many applications involve a large number of variables to be modelled using a relatively small patient sample. Problems of overfitting and of identifying important covariates are exacerbated in analysing prognosis because the accuracy of a model is more a function of the number of events than of the sample size. We used a general index of predictive discrimination to measure the ability of a model developed on training samples of varying sizes to predict survival in an independent test sample of patients suspected of having coronary artery disease. We compared three methods of model fitting: (1) standard 'step-up' variable selection, (2) incomplete principal components regression, and (3) Cox model regression after developing clinical indices from variable clusters. We found regression using principal components to offer superior predictions in the test sample, whereas regression using indices offers easily interpretable models nearly as good as the principal components models. Standard variable selection has a number of deficiencies.

Coronary Disease↗
PubMedDate not supplied

Predicting the outcomes of electrophysiologic studies of patients with unexplained syncope: preliminary validation of a derived model.

PURPOSE: To develop and validate a predictive model that would allow clinicians to determine whether an electrophysiologic (EP) study is likely to result in useful diagnostic information for a patient who has unexplained syncope. PATIENTS: One hundred seventy-nine consecutive patients with unexplained syncope who underwent EP studies at two university medical centers comprised the training sample. A test sample to validate the model was made up of 138 patients from the clinical literature who had undergone EP studies for syncope. DESIGN: Retrospective analysis of patients undergoing EP studies for syncope. The data collector was blinded to the study hypothesis; the electrophysiologist assessing outcomes was blinded to clinical and historical data. Clinical predictor variables available from the history, the physical examination, electrocardiography (ECG), and Holter monitoring were analyzed via two multivariable predictive modeling strategies (ordinal logistic regression and recursive partitioning) for their abilities to predict the results of EP studies, namely tachyarrhythmic and bradyarrhythmic outcomes. These categories were further divided into full arrhythmia and borderline arrhythmia groups. RESULTS: Important outcomes were 1) sustained monomorphic ventricular tachycardia (VT) and 2) bradyarrhythmias, including sinus node and atrioventricular (AV) conducting disease. The results of the logistic regression (in this study, the superior strategy) showed that the presence of organic heart disease [odds ratio (OR) = 3.0, p less than 0.001] and frequent premature ventricular contractions on ECG (OR = 6.7, p less than 0.004) were associated with VT, while the following abnormal ECG findings were associated with bradyarrhythmias: first-degree heart block (OR = 7.9, p less than 0.001), bundle-branch block (OR = 3.0, p less than 0.02), and sinus bradycardia (OR = 3.5, p less than 0.03). Eighty-seven percent of the 31 patients with important outcomes at EP study had at least one of these clinical risk factors, while 95% of the patients with none of these risk factors had normal or nondiagnostic EP studies. In the validation sample, the presence of one or more risk factors would have correctly identified 88% of the test VT patients and 65% of the test bradyarrhythmia patients as needing EP study. CONCLUSION: These five identified predictive factors, available from the history, the physical examination, and the initial ECG, could be useful to clinicians in selecting those patients with unexplained syncope who will have a serious arrhythmia identified by EP studies.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Prevention of sudden death in patients with coronary artery disease: the Multicenter Unsustained Tachycardia Trial (MUSTT).

This trial will significantly advance our understanding of the prognostic and therapeutic usefulness of electrophysiologic studies in patients with coronary artery disease. Several features of this trial are worth emphasizing. First, the protocol for performing programmed stimulation and serial drug testing is designed to mirror those currently in use by many practicing electrophysiologists. While practice patterns vary, the procedures used in the trial reflect what is considered "usual and standard" practice. Second, because half of the patients with inducible sustained ventricular tachycardia will be given no antiarrhythmic therapy, we will be able to ascertain the true risk of sudden death in this patient population without the influence of these agents. Third, this trial will assess the usefulness of a method of guiding antiarrhythmic therapy (electrophysiologic testing) to reduce mortality in this high-risk population. It will not evaluate the efficacy of a specific type of antiarrhythmic therapy.

Amiodarone↗
PubMedDate not supplied

Psychosocial and physical predictors of anginal pain relief with medical management.

This study was undertaken to identify psychosocial and physical characteristics that independently predict anginal pain relief. The original study group comprised over 570 patients in whom the characteristics were identified at the time of coronary arteriography and who were followed up after 6 months of standard medical therapy. In the subset of 382 of these patients who were assessed as having NYHA Class III or IV angina at the time of angiography, a multivariable analysis of 101 baseline descriptors showed that higher scores on the MMPI hypochondriasis scale, unemployment, and more severe right coronary occlusion were significant independent predictors of failure to achieve two-class improvement at follow-up. These three characteristics also predicted continuing severe angina in a subsequent, independent sample of 91 new patients. These findings could help physicians select appropriate treatment by prospectively identifying patients who are unlikely to respond to standard medical treatment of angina.

Adrenergic beta-Antagonists↗