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Biomedical subjects

R C Pasternak

Publications and source records attributed to R C Pasternak.

9 recordsLinked to original sources
PubMed1992

Cost effectiveness of thrombolytic therapy with streptokinase in elderly patients with suspected acute myocardial infarction.

BACKGROUND: There is a lack of consensus among cardiologists about the potential benefit of thrombolytic therapy for suspected acute myocardial infarction in older patients. To investigate this issue, we constructed a decision-analytic model for patients 75 years of age or older who present with ST-segment elevation within six hours of the onset of symptoms suggesting acute myocardial infarction. METHODS: The variables incorporated in this model were the probability that the patient has an acute myocardial infarction, the probability of in-hospital death among patients with acute myocardial infarction who do not receive thrombolytic therapy, the probability of a fatal or incapacitating complication resulting from thrombolytic therapy, and the expected relative reduction in the risk of death associated with thrombolytic therapy in patients with acute myocardial infarction. Our analyses were based primarily on the use of streptokinase as the thrombolytic agent. RESULTS: Given our base-line assumptions, the probability of dying in the hospital was 21.4 percent if thrombolytic therapy was given and 24.4 percent if it was not given. In one-way sensitivity analyses, thrombolytic therapy decreased the risk of dying if the probability that the patient had an acute myocardial infarction was assumed to be greater than 9 percent, if the probability of dying in the hospital after an acute myocardial infarction without thrombolytic therapy was assumed to be greater than 3 percent, if the rate of fatal or incapacitating complications due to thrombolytic therapy was assumed to be 4 percent or less, or if the relative reduction in the risk of death associated with thrombolytic therapy was assumed to be greater than 1 percent. On the basis of our base-line assumptions, our estimate of the cost effectiveness of streptokinase therapy (the cost per year of life saved) for an 80-year-old patient with suspected acute myocardial infarction was $21,200. For a wide range of assumptions about risks, benefits, and costs, the cost per year of life saved remained less than $55,000. CONCLUSIONS: Within the limitations imposed by the assumptions used in our analysis, thrombolytic therapy with streptokinase was found to be a beneficial and cost-effective treatment for suspected acute myocardial infarction in elderly patients in a wide variety of clinical circumstances.

Age Factors↗
PubMed1992

Quantitative angiographic and statistical methods to assess serial changes in coronary luminal diameter and implications for atherosclerosis regression trials.

The purpose of this study was (1) to determine a threshold for categorizing individual coronary lesions as either significantly progressing or regressing, (2) to determine whether multiple lesions within individual patients progress at independent rates, and (3) to calculate sample sizes for atherosclerosis regression trials. Seventeen patients with 46 significant lesions (2.7 lesions/patient) underwent repeat coronary arteriography 3.0 years apart. With use of the standard error of the mean change in diameter from initial to repeat catheterization across 5 pairs of consecutive end-diastolic frames, individual lesions were categorized as either significantly (p less than 0.01) progressing or regressing if there was a 0.27 mm change in minimum diameter or a 7.8 percent point change in percent stenosis. The mean diameter change of a sample of lesions can also be analyzed as a continuous variable using either the lesions or the patient as the primary unit of analysis. A lesion-specific analysis can be accomplished using a multiple regression model that accounts for the intraclass correlation (rho) in the degree of change among multiple lesions within individual patients. The intraclass correlations in percent stenosis (rho = 0.01) and minimum diameter (rho = -0.24) were low, indicating that disease progression in different lesions within individual patients is nearly independent. With use of this model, 50 patients per treatment group would permit the detection of a 5.5% difference between treatment group means in the change in minimum diameter and a 2.7% percentage point (not percent) difference in the change in percent stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Selection of patients for coronary angiography and coronary revascularization early after myocardial infarction: is there evidence for a gender bias?

OBJECTIVE: To determine whether a gender bias exists in the selection of patients for diagnostic and therapeutic cardiovascular procedures early after myocardial infarction. DESIGN: A retrospective cohort study. SETTING: A community-based tertiary care teaching hospital. PATIENTS: A total of 2473 consecutive patients with a principal discharge diagnosis of acute myocardial infarction and a peak creatine kinase MB fraction of at least 4%. MEASUREMENTS: Comparison of men and women regarding the frequency with which they underwent various cardiac procedures. RESULTS: Women had coronary angiography during hospitalization for myocardial infarction much less frequently than men (odds ratio, 0.55; 95% Cl, 0.46 to 0.65), but the age-adjusted rates were similar in women and men (odds ratio, 0.91; Cl, 0.75 to 1.12). An abnormal ejection fraction (less than 50%) was equally frequent in women and men who underwent left ventriculography (odds ratio, 0.85; Cl, 0.56 to 1.30). Among patients who had coronary angiography, women had a significantly lower rate of severe coronary artery disease, defined as either a left main stenosis of more than 50%, three-vessel disease, or two-vessel disease with a proximal left anterior descending stenosis of more than 70% (odds ratio, 0.67; Cl, 0.48 to 0.93). When adjustments were made for age, women had percutaneous transluminal coronary angioplasty as often as men (odds ratio, 1.16; Cl, 0.83 to 1.62) but had coronary artery bypass graft surgery significantly less frequently (odds ratio, 0.58; Cl, 0.37 to 0.91). When adjustments were made for age and the severity of coronary artery disease, the difference in rates was of borderline significance (odds ratio, 0.65; Cl, 0.41 to 1.01). CONCLUSIONS: No evidence of a difference in the rate of coronary angiography early after myocardial infarction between women and men was found after age adjustment. Among patients who have cardiac catheterization early after myocardial infarction, women and men are equally likely to have angioplasty, but women are less likely than men to have coronary artery bypass surgery.

Adult↗
PubMed1979

Variant angina. Clinical spectrum and results of medical and surgical therapy.

Fifty-four patients with variant angina are described. They are divided into patients without hemodynamically (less than 50%) important coronary artery lesions (Group 1), patients with intermediate (greater than or equal to 50% and less than 90%) fixed obstruction (Group 2A), and patients with high grade (greater than or equal to 90%) fixed obstruction (Group 2B). Inferior ischemia occurred significantly more often in Group 1 (90% versus 33%. p less than 0.001), and exertional angina was more frequent in Group 2 (70% versus 36%, p less than 0.05). Maximum medical therapy with propranolol and nitrates failed to control angina in 55% of Group 1, 69% of Group 2A, and 63% of Group 2B. Twelve patients underwent intra-aortic balloon pumping (IABP), and in 10 there was complete control of variant angina. A total of 35 Group I patients underwent coronary artery bypass grafting (CABG), with a 2.9% mortality rate in patients without preoperative cardiogenic shock. Of these patients, 55% in Group 2A and 73% in Group 2B experienced marked improvement in their angina status. Therefore, we currently recommend bypass grafting for medically intractable variant angina in those patients with severely stenotic, fixed atherosclerotic lesions.

Angina Pectoris↗
PubMed1976

Echocardiographic diagnosis of large fungal verruca attached to mitral valve.

In a patient with endocarditis due to Candida tropicalis echocardiograms from mitral valve vegetations were found to mimic the typical pattern of a left atrial myxoma. A mass was shown occupying the mitral orifice posterior to the anterior mitral leaflet; densities also appeared in the left atrium. Though these echocardiographic findings were consistent with the diagnosis of a left atrial myxoma, there were other distinctive differential diagnostic features. Other diagnostic possibilities must, therefore, be considered in the interpretation of echocardiograms which suggest left atrial tumour.

Candida↗