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D B Mark

Publications and source records attributed to D B Mark.

At least 145 records · Page 8Linked to original sources
PubMed1990

Feasibility and cost-saving potential of outpatient cardiac catheterization.

To determine the feasibility and cost-saving potential of substituting outpatient for inpatient cardiac catheterization, 986 consecutive procedures were studied at a large referral hospital. Patients were classified prospectively as to their eligibility for outpatient cardiac catheterization according to published guidelines. Resource consumption was recorded, and cost savings were then calculated by analyzing the specific supply and personnel costs that could change as a result of inpatient versus outpatient status. Of the total of 986 patients who underwent diagnostic catheterization, 240 (24%) were outpatients, 279 (28%) were inpatients but had no exclusion criteria for outpatient catheterization and 467 (47%) were inpatients who had one or more exclusions for outpatient catheterization. The most common reasons for exclusion from outpatient catheterization were congestive heart failure (22%), unstable angina (15%), noncoronary heart disease (14%), recent myocardial infarction (11%) and severe noncardiac disease (9%). Inpatients with no exclusions for the outpatient procedure tended to be sicker than outpatients because they were older (p = 0.002), had a lower ejection fraction (p = 0.009) and had more triple vessel coronary artery disease (p less than 0.0001). The cost of the catheterization procedure itself was not different between inpatients and outpatients. Laboratory testing was more frequent among inpatients, however, and "room and board" costs were significantly higher. Although the difference in hospital charges for inpatients and outpatients was $580, a rigorous analysis indicated that the potential cost savings was only 38% of this amount, or $218 per eligible patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗
PubMed1990

Prognostic value of radionuclide angiography in medically treated patients with coronary artery disease. A comparison with clinical and catheterization variables.

To evaluate the usefulness of multiple measures from rest and exercise radionuclide angiography (RNA) in predicting cardiovascular death and cardiovascular events (death or nonfatal myocardial infarction) and to assess the prognostic usefulness of the RNA relative to clinical and catheterization data, we studied 571 stable patients with symptomatic coronary artery disease who had upright rest/exercise first-pass RNA within 3 months of catheterization and were medically treated. With a median follow-up of 5.4 years, 90 patients have died from cardiovascular causes, and 147 patients have either died or suffered a nonfatal myocardial infarction. Using the Cox regression model and a preselected group of RNA variables, the most important RNA predictor of mortality was exercise ejection fraction (chi 2 = 81, p less than 0.00001). Neither rest ejection fraction nor the change in ejection fraction from rest to exercise contributed additional predictive information. Two other RNA study variables, the change in heart rate from rest to exercise and rest end-diastolic volume index, did contribute additional prognostic information to the exercise ejection fraction (chi 2 = 23, p less than 0.0001). Compared with noninvasive clinical data (history, physical examination, electrocardiogram, and chest radiograph), RNA variables were considerably more predictive of mortality (chi 2 = 71 [clinical variables] versus chi 2 = 104 [RNA]). Remarkably, the strength of the relation of RNA variables with mortality was equivalent to that of the set of catheterization variables previously demonstrated in our large angiographic population to be prognostically important (chi 2 = 104 [RNA] versus chi 2 = 102 [catheterization variables]). The RNA contained 84% of the information provided by clinical and catheterization descriptors combined. Furthermore, the RNA contributed significant additional prognostic information to the clinical and catheterization data (chi 2 = 13.6, p = 0.0035). For cardiovascular events, the relative prognostic usefulness of the RNA was similar, although relations with this outcome were generally weaker. Descriptors from the rest/exercise RNA exhibit a powerful relation with long-term outcomes and can be useful in defining risk, even when clinical and catheterization data are available.

Cardiac Catheterization↗
PubMed1990

Resource use and cost of initial coronary revascularization. Coronary angioplasty versus coronary bypass surgery.

Although there is intense interest in the cost-saving potential of therapeutic alternatives, most studies have analyzed hospital charges rather than actual economic costs. To analyze cost differences rigorously, we studied 115 patients undergoing initial elective angioplasty (percutaneous transluminal coronary angioplasty, PTCA) and 274 patients undergoing initial elective surgery (coronary artery bypass graft surgery, CABG). Detailed resource consumption profiles were constructed and used to estimate the cost savings from switching a patient from CABG to PTCA. Four cost-accounting methods were used in the analysis; each method made different assumptions about the costs that would vary and the costs that would be fixed according to the number of procedures performed. The variable costs in the four methods were the 1) cost of supplies, 2) cost of personnel and supplies, 3) average direct costs, and 4) average direct costs plus allocated hospital overhead. The mean hospital charges for CABG patients were $19,644 versus $9,556 for PTCA patients (p less than 0.0001). The estimated cost difference between CABG and PTCA was substantially less than the $10,088 difference in charges, however, with net savings of 19%, 46%, 53%, and 78% of charges using cost-accounting methods 1-4, respectively. Thus, although the initial hospital charges for PTCA are significantly less than for CABG, the actual economic cost savings may be significantly overestimated by the use of hospital charge data.

Accounting↗
PubMed1989

Bleeding during thrombolytic therapy for acute myocardial infarction: mechanisms and management.

Hemorrhage is the major adverse effect of thrombolytic therapy, but its incidence can be reduced by careful selection of patients and avoidance of unnecessary invasive procedures. More than 70% of bleeding episodes occur at vascular puncture sites. Hypofibrinogenemia and elevation of fibrinogen degradation products have been weakly correlated with the risk of hemorrhage. Although depletion of factors V and VIII may occur, the role of such depletion in bleeding is unknown. Several in-vitro studies have shown plasmin-induced platelet dysfunction, but clinical data are limited. Nevertheless, the role of platelet inhibition should be considered because many patients are treated with antiplatelet agents. Most patients who have bleeding can be managed by interruption of thrombolytic and anticoagulant therapy, volume replacement, and manual pressure applied to an incompetent vessel. Protamine should be considered if heparin has been administered within 4 hours of the onset of bleeding. In the few patients who fail to respond to these conservative measures, judicious use of transfusion products may be indicated. Transfusion of cryoprecipitate, fresh frozen plasma, and platelets should be considered with clinical and laboratory reassessment after each administration. A target fibrinogen level of 1 g/L is desirable with cryoprecipitate infusion. Antifibrinolytic agents are available as a last alternative. We have developed an algorithm for using these products.

Antifibrinolytic Agents↗
PubMed1989

Clinical correlates and prognostic significance of type A behavior and silent myocardial ischemia on the treadmill.

Type A patients with coronary artery disease (CAD) tend to ignore or underreport symptoms, especially during challenging tasks such as the treadmill exercise test. To determine whether type A CAD patients might be more likely than type B patients to have silent ischemia during exercise and consequently a worse prognosis, 403 patients with stable CAD who had significant coronary disease on angiography, a positive Bruce protocol treadmill test and a structured interview to assess type A behavior were studied. Median follow-up time was 6 years. Type A patients were more likely to experience silent ischemia during exercise than were type B patients (35 vs 25%, p = 0.05). Patients with silent ischemia during exercise had a history of fewer anginal episodes/week, and type A patients with silent ischemia were less likely to have had a history of typical angina. However, using the Cox model, there were no significant differences in survival between type A patients and B patients with silent ischemia (4-year survival 86 vs 79%, p = 0.44) and no significant differences in survival between type A patients with silent ischemia and type A patients with symptomatic ischemia (6-year survival 86 vs 80%, p = 0.59). Similar results were obtained for infarction-free survival. Type A patients are more likely than type B patients to have silent ischemia during exercise, but long-term survival is not affected.

Angina Pectoris↗
PubMed1989

A brief self-administered questionnaire to determine functional capacity (the Duke Activity Status Index).

To develop a brief, self-administered questionnaire that accurately measures functional capacity and assesses aspects of quality of life, 50 subjects undergoing exercise testing with measurement of peak oxygen uptake were studied. All subjects were questioned about their ability to perform a variety of common activities by an interviewer blinded to exercise test findings. A 12-item scale (the Duke Activity Status Index) was then developed that correlated well with peak oxygen uptake (Spearman correlation coefficient 0.80). To test this new index, an independent group of 50 subjects completed a self-administered questionnaire to determine functional capacity and underwent exercise testing with measurement of peak oxygen uptake. The Duke Activity Status Index correlated significantly (p less than 0.0001) with peak oxygen uptake (Spearman correlation coefficient 0.58) in this independent sample. The Duke Activity Status Index is a valid measure of functional capacity that can be obtained by self-administered questionnaire.

Activities of Daily Living↗
PubMed1989

The evolution of medical and surgical therapy for coronary artery disease. A 15-year perspective.

To elucidate the factors associated with improved survival following coronary artery bypass surgery, we studied 5809 patients receiving medical or surgical therapy for coronary artery disease. Three factors were associated with a significant surgical survival benefit: more severe coronary disease, a worse prognosis with medical therapy, and a more recent operative date. Patients with more extensive coronary obstruction had the greatest improvement in survival. Patients with a poor prognosis because of factors such as older age, severe angina, or left ventricular dysfunction had a reduction in risk that was proportionate to their overall risk on medical therapy. Survival with surgery progressively improved over the study period and by 1984 surgery was significantly better than medical therapy for most patient subgroups. Thus, contemporary coronary revascularization is associated with improved longevity in many patients with ischemic heart disease, especially in those with adverse prognostic indicators.

Age Factors↗
PubMed1989

Prediction of early recurrent myocardial ischemia and coronary reocclusion after successful thrombolysis: a qualitative and quantitative angiographic study.

To determine the association of qualitative and quantitative measurements of the myocardial infarct-related coronary narrowing with subsequent recurrent ischemia/reocclusion after successful thrombolysis, 47 patients treated with high-dose (150 mg) tissue plasminogen activator over 6 to 8 hours were studied in the setting of acute myocardial infarction. No patient underwent emergent coronary angioplasty. All patients had Thrombolysis in Myocardial Infarction (TIMI) grade 2 flow or higher at the baseline (90-minute) angiogram; 31 patients had a protocol 24-hour catheterization as well. Eighteen patients had recurrent ischemia/reocclusion whereas 29 had an uneventful hospital course. There was no significant difference in baseline clinical characteristics between the 2 groups. Twenty-five (86%) of those with an uneventful course had TIMI grade 3 flow at baseline angiogram compared with 56% of patients with recurrent events. No significant difference in angiographic morphologic characteristics was found between the 2 groups at baseline catheterization. At 24 hours, however, none of the patients who subsequently had recurrent events had a concentric narrowing, while 13 (58%) of them had a complex morphology. In contrast, quantitative parameters of minimal lumen diameter, percent area stenosis and percent diameter stenosis at baseline and 24 hours were not significantly different between those who did and did not have recurrent ischemia/reocclusion. These findings suggest that the degree and quality of coronary flow at baseline catheterization are more important determinants of sustained patency and event-free hospitalization than are quantitative dimensions or coronary morphology. In addition, narrowings that fail to become concentric within the first 24 hours are more likely to be associated with subsequent ischemia or reocclusion during the early periinfarct period.

Aged↗
PubMed1989

Painless exercise ST deviation on the treadmill: long-term prognosis.

To evaluate the clinical correlates and long-term prognostic significance of silent ischemia during exercise, 1,698 consecutive symptomatic patients with coronary artery disease who had both treadmill testing and cardiac catheterization were studied. These patients were classified into three groups: Group 1 = patients with no exercise ST deviation (n = 856), Group 2 = patients with painless exercise ST deviation (n = 242) and Group 3 = patients with both angina and ST segment deviation during exercise (n = 600). Patients with exercise angina had a history of a longer and more aggressive anginal course (with a greater frequency of angina, with nocturnal episodes and/or progressive symptom pattern) and more severe coronary artery disease (almost two-thirds had three vessel disease). The 5 year survival rate among the patients with painless ST deviation was similar to that of patients without ST deviation (86% and 88%, respectively) and was significantly better than that of patients with both symptoms and ST deviation (5 year survival rate 73% in patients with exercise-limiting angina). Similar trends were obtained in subgroups defined by the amount of coronary artery disease present. In the total study group of 1,698 patients, silent ischemia on the treadmill was not a benign finding (average annual mortality rate 2.8%) but, compared with symptomatic ischemia, did indicate a subgroup of patients with coronary artery disease who had a less aggressive anginal course, less coronary artery disease and a better prognosis. Thus, silent ischemia during exercise testing in patients with symptomatic coronary artery disease represents an intermediate risk response in the spectrum of exercise-induced ischemia.

Adult↗
PubMed1989

Exercise treadmill testing is a poor predictor of anatomic restenosis after angioplasty for acute myocardial infarction.

This study evaluated whether an exercise treadmill test could predict restenosis in 289 patients 6 months after a successful emergency angioplasty of the infarct-related artery for acute myocardial infarction. After excluding those with interim interventions (64), medical events (36), or medical contraindications to follow-up testing (25), both a treadmill test and a cardiac catheterization were completed in 144 patients, 88% of those eligible for this assessment. Four patients with left bundle branch block or pacemaker rhythm at the time of treadmill testing were also excluded from analysis. Of six follow-up clinical and treadmill variables examined by multivariable logistic regression analysis, only exercise ST deviation was independently correlated with restenosis at follow-up (chi 2 = 5, p = 0.02). The clinical diagnosis of angina at follow-up, although marginally related to restenosis when considered by itself (p = 0.04), did not add significant information once ST deviation was known. The sensitivity of ST deviation of 0.10 mV or greater for detecting restenosis was only 24% (13 of 55 patients), and the specificity was 88% (75 of 85 patients). The sensitivity of exercise-induced ST deviation for detection of restenosis was not affected by extent or severity of wall motion abnormalities at follow-up, by the timing of thrombolytic therapy or of angioplasty, or by the presence of collateral blood flow at the time of acute angiography. A second multivariable analysis evaluating the association of the same variables with number of vessels with significant coronary disease at the 6-month catheterization found an association with both exercise ST deviation (p = 0.003) and exercise duration (p = 0.04). Angina symptoms and exercise treadmill test results in this population had limited value for predicting anatomic restenosis 6 months after emergency angioplasty for acute myocardial infarction.

Angina Pectoris↗
PubMed1989

Clinical experience and predicting survival in coronary disease.

To study the accuracy with which long-term prognosis can be predicted in patients with coronary artery disease, prognostic predictions obtained from a large, diverse sample of practicing cardiologists were compared with predictions from a multivariable statistical model. Test samples of 10 patients each were selected from a large series of medically treated patients with significant coronary disease. Using detailed clinical summaries, 49 cardiologists each predicted the probability of 3-year survival and infarction-free survival for 10 patients. Cox regression models, developed using patients who were not in the test samples, were also used to predict corresponding outcome probabilities for each test patient. Overall, the model estimates of prognosis were significantly better than the doctors' predictions. The rank correlation of model predictions with 3-year survival was 0.60, compared with 0.52 for the physicians. Model predictions added significant prognostic information to the doctors' predictions, whereas the converse was not true. Where predictions were made by multiple doctors, the inter-physician variability was substantial. Neither practice characteristics nor extent of clinical experience significantly affected the physicians' predictive accuracy. In coronary artery disease, statistical models developed from carefully collected data can provide prognostic predictions that are more accurate than predictions of experienced clinicians made from detailed case summaries.

Coronary Disease↗
PubMed1988

Helicopter transport of patients during acute myocardial infarction.

Initial experience with a regional system of emergency helicopter transport of patients with acute myocardial infarction (AMI) referred for emergent cardiac catheterization and percutaneous transluminal coronary angioplasty (PTCA) is described. Two hundred fifty patients with AMI were transported from within a 150-mile radius to Duke University Medical Center over a 15-month period. All patients were within 12 hours of onset of symptoms. Thrombolytic therapy was administered to 240 (96%) patients (72% before or in-flight). The time to administration of thrombolytic therapy ranged from 30 to 120 minutes (median 180), while the time to arrival in the interventional catheterization laboratory ranged from 105 to 815 minutes (median 300). The flight time was 12 to 77 minutes (median 31). Most patients had 1- or 2-vessel coronary artery disease; the baseline ejection fraction ranged from 27 to 70% (median 42). Transient hypotension was the most common complication both pre-flight and in-flight. Third-degree atrioventricular block and nonsustained ventricular tachycardia were the next most common complications. Ventricular fibrillation or sustained ventricular tachycardia occurred before takeoff in 38 patients (15%). No patients had ventricular fibrillation, asystole or respiratory arrest during transport. Fluid boluses for hypotension were the most common intervention. Five patients required cardiopulmonary resuscitation in-flight; 3 before lift-off and 2 required a brief period of cardiopulmonary resuscitation during sustained ventricular tachycardia. Fourteen patients had pressor therapy, military antishock trousers or both to maintain adequate blood pressure. Neither cardioversion, defibrillation nor intubation were performed in-flight. Thus, inflight complications are infrequent and can be managed en route to an intervention center.(ABSTRACT TRUNCATED AT 250 WORDS)

Aircraft↗
PubMed1988

Adoption of thrombolytic therapy in the management of acute myocardial infarction.

A national survey of 1,065 physicians was carried out to document current use of thrombolytic therapy for acute myocardial infarction (AMI). In early 1987, thrombolytic therapy was used by 66% of respondents. Among those who used thrombolytic therapy, 92% used streptokinase, 13% used tissue-type plasminogen activator and 3% used urokinase. Most (72%) used intravenous administration exclusively and only 5% used intracoronary administration exclusively. Despite widespread acceptance of thrombolytic therapy, most physicians gave it to less than 25% of their patients. Duration of symptoms was rated as the single most important factor affecting the decision to use thrombolytic therapy; 45% had a time limit of less than 4 hours and 85% had a time limit of less than 6 hours. Complications of AMI and electrocardiographic findings were factors also considered in the decision to give this therapy. A physician's adoption of thrombolytic therapy was significantly associated with several characteristics: specialty type, number of AMI patients treated, physician age and access to cardiac catheterization. In addition, physicians using thrombolytic therapy had a significantly different use of medications and laboratory tests for all patients with AMI. This survey documents rapid acceptance of thrombolytic therapy for AMI, particularly in patients with short duration of symptoms or evidence of high risk.

Cardiac Catheterization↗
PubMed1988

Trends in physician management of uncomplicated acute myocardial infarction, 1970 to 1987.

To document current management of uncomplicated acute myocardial infarction (AMI), a national survey of 1,065 physicians was performed. Items from previous surveys in 1970 and 1979 were included to permit analysis of time trends in management. Median hospital stay dropped from 21 days in 1970 to 9 days in 1987. Use of beta blockers and aspirin doubled between 1979 and 1987, while use of anticoagulation and sulfinpyrazone dropped 4- to 10-fold. In 1987, coronary angiography was used commonly, especially in younger patients or those with either a non-Q-wave AMI, intravenous thrombolytic therapy or a positive exercise test. These findings document the increasingly aggressive approach to the management of patients with uncomplicated AMI.

Activities of Daily Living↗
PubMed1988

Comparison of predictions based on observational data with the results of randomized controlled clinical trials of coronary artery bypass surgery.

Clinical decisions are most secure when based on findings from several large randomized clinical trials, but relevant randomized trial data are often unavailable. Analyses using clinical data bases might provide useful information if statistical methods can adequately correct for the lack of randomization. To test this approach, the findings of the three major randomized trials of coronary bypass surgery were compared with predictions of multivariable statistical models derived from observations in the Duke Cardiovascular Disease Databank. Clinical characteristics of patients at Duke University Medical Center who met eligibility requirements for each major randomized trial were used in the models to predict 5 year survival rates expected for medical and surgical therapy in each randomized trial. Model predictions agreed well with randomized trial results and were within the 95% confidence limits of the observed survival rates in 24 (92%) of 26 clinical subgroups. The overall correlation between predicted and observed survival rates was good (Spearman coefficient 0.73, p less than 0.0001). These results suggest that carefully performed analyses of observational data can complement the results of randomized trials.

Angina Pectoris↗
PubMed1988

Importance of clinical measures of ischemia in the prognosis of patients with documented coronary artery disease.

To examine the value of clinical measures of ischemia for stratifying prognosis, 5,886 consecutive patients who had symptomatic significant (greater than or equal to 75% stenosis) coronary artery disease were studied. Using the Cox regression model in a randomly selected half of the patients, the prognostically independent clinical variables were weighted and arranged into a simple angina score: angina score = angina course X (1 + daily angina frequency) + ST-T changes, where angina course was equal to 3 if unstable or variant angina was present, 2 if the patient's angina was progressive with nocturnal episodes, 1 if it was progressive without nocturnal symptoms and 0 if it was stable; 6 points were added for the presence of "ischemic" ST-T changes. This angina score was then validated in an independent patient sample. The score was a more powerful predictor of prognosis than was any individual anginal descriptor. Furthermore, the angina score added significant independent prognostic information to the patient's age, sex, coronary anatomy and left ventricular function. Patients with three vessel disease and a normal ventricle (n = 1,233) had a 2 year infarction-free survival rate of 90% with an angina score of 0 and a 68% survival rate with an angina score greater than or equal to 9. With an ejection fraction less than 50% and three vessel disease (n = 1,116), the corresponding infarction-free survival figures were 76 and 56%.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1988

Prognostic value of the simplified Selvester QRS score in patients with coronary artery disease.

The relation of the simplified Selvester QRS scoring system for the estimation of myocardial infarct size to survival was studied in 1,915 nonsurgically treated patients with documented coronary artery disease. Electrocardiograms (ECGs) were scored according to a simplified 29 point QRS scoring system. Using Cox model analyses, QRS scores were found to provide strong prognostic information by themselves (p less than 0.0001). Higher QRS scores were associated with lower survival rates. Patients with a score of 0 had a 1 year survival rate of 95% and a 5 year survival rate of 88%; patients with a score of 10 or more had survival rates of 81 and 52%, respectively, at the same intervals. Directly compared with the presence or absence of Q waves on the ECG, QRS scores provided greater prognostic information (p less than 0.001). When compared with 13 individual factors previously shown to provide the greatest independent prognostic information, the QRS score was the third most powerful individual prognostic factor. It did not contribute independent prognostic information in combination with the whole group, but did provide independent information in combination with the six most predictive factors. Its prognostic information overlapped mostly with clinical factors related to heart failure, and combined best with clinical factors related to the severity of ongoing myocardial ischemia. Because it is inexpensive and simple and maximizes the prognostic information from the ECG, the simplified Selvester QRS scoring system can be a useful clinical descriptor for practitioners and clinical investigators.

Cardiac Catheterization↗