Post-mortem three-dimensional reconstruction of the entire coronary arterial circulation using electron-beam computed tomography.
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Autopsy↗
Biomedical subjects
A G Wasserman
Publications and source records attributed to A G Wasserman.
The continuation of the Prevention of Events With Angiotensin-Converting Enzyme Inhibition (PEACE) Trial.
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Angiotensin-Converting Enzyme Inhibitors↗
Measuring contributions to the clinical mission of medical schools and teaching hospitals.
This is the final report of a panel convened as part of the Association of American Medical College's (AAMC's) Mission-based Management Program to examine the use of metrics (i.e., measures) in assessing faculty and departmental contributions to the clinical mission. The authors begin by focusing on methods employed to estimate clinical effort and calculate a "clinical full-time equivalent," a prerequisite to comparing productivity among faculty members and departments. They then identify commonly used metrics, including relative-value units, total patient-care gross charges, total net patient fee-for-service revenue, total volume per CPT (current procedural terminologies) code by service category and number of patients per physician, discussing their advantages and disadvantages. These measures reflect the "twin pillars" of measurement criteria, those based on financial or revenue information, and those based on measured activity. In addition, the authors urge that the assessment of quality of care become more highly developed and integrated into an institution's measurement criteria. The authors acknowledge the various ways users of clinical metrics can develop standards against which to benchmark performance. They identify organizations that are sources of information about external national standards, acknowledge various factors that confound the interpretation of productivity data, and urge schools to identify and measure secondary service indicators to assist with interpretation and provide a fuller picture of performance. Finally, they discuss other, non-patient-care, activities that contribute to the clinical mission, information about which should be incorporated into the overall assessment. In summary, the authors encourage the use of clinical productivity metrics as an integral part of a comprehensive evaluation process based upon clearly articulated and agreed-upon goals and objectives. When carefully designed, these measurement systems can provide critical information that will enable institutional leaders to recognize and reward faculty and departmental performance in fulfillment of the clinical mission.
Efficiency, Organizational↗
Using coronary calcification scanning in the clinical practice of preventive cardiology.
Preventive therapies such as cholesterol reduction significantly reduce the risk of acute coronary events. Diagnostic tools that identify asymptomatic coronary atherosclerosis would permit initiation of aggressive preventive therapies at an earlier stage of coronary disease. Histologic and angiographic data demonstrate that coronary calcium has a very high sensitivity for the presence of coronary plaque. Therefore, coronary calcification can be regarded as a marker for coronary atherosclerosis. Coronary calcium scanning has been suggested as a tool for identification of a high-risk asymptomatic patient group. It can be utilized to guide the aggressiveness of risk factor modification and therapeutic preventive interventions toward those at higher risk for future events. Based on the available data, we review the clinical use of coronary calcium scanning in preventive cardiology.
Calcinosis↗
Electron beam computed tomographic angiography and 3-dimensional reconstruction of a stented saphenous vein graft.
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Aged↗
Alterations in serum levels of lipids and lipoproteins with indinavir therapy for human immunodeficiency virus-infected patients.
Alterations in lipid metabolism have been associated with the use of protease inhibitors. Sequential lipid analyses were performed on serum samples from human immunodeficiency virus-infected antiretroviral-naive patients who received indinavir in combination with two nucleoside reverse transcriptase inhibitors. Serum levels of cholesterol, triglycerides, high-density lipoproteins (HDLs), and low-density lipoproteins (LDLs) were measured at baseline and at periodic intervals. After 48 weeks of indinavir therapy, mean serum levels +/- SD rose as follows: cholesterol, from 167.2 +/- 36.0 to 206.3 +/- 32.4 mg/dL (P < .0005); triglycerides, from 110.4 +/- 47.5 to 158.4 +/- 72.5 mg/dL (P < .0101); and LDLs, from 106.6 +/- 35.1 to 136.1 +/- 31.6 mg/dL (P = .0029). There was no significant change in the serum HDL fraction. Mean serum lipoprotein (a) levels +/- SD rose from 6.5 +/- 1.4 to 9.6 +/- 2.0 mg/dL after 30 weeks (P = .0695). Potential mechanisms for the noted increases include alterations in serum lipoprotein lipase activity or changes in hepatic lipid metabolism. The clinical significance of these changes remains to be determined.
Cholesterol↗
Doppler guide wire flow-velocity indexes measured distal to coronary stenoses associated with reversible thallium perfusion defects.
A Doppler guide wire was used to measure phasic coronary blood flow velocity distal to coronary stenoses in 17 symptomatic patients with corresponding positive exercise or adenosine thallium scintigrams. Distal average peak velocity and diastolic/systolic flow-velocity ratio were obtained in 16 vessels with stenoses (55% to 85% diameter stenosis) and a corresponding reversible thallium defect and in 11 control vessels with no stenosis or thallium defect. Coronary flow-velocity reserve was obtained with intracoronary adenosine. Coronary flow reserve (2.3 +/- 0.4 vs 1.2 +/- 0.3, p < 0.01) and diastolic/systolic flow-velocity ratio (1.95 +/- 0.56 vs 1.44 +/- 0.59, p < 0.04) were significantly different between normal vessels and distal to stenoses, respectively. Excellent concordance between distal coronary flow reserve and diastolic/systolic flow-velocity ratio to thallium scintigraphy was noted. A coronary flow reserve of < 1.8 and a diastolic/systolic flow-velocity ratio of < 1.7 predicted a reversible thallium perfusion scintigram (concordance 96% and 88%, respectively). Distal coronary flow velocity indexes may provide an alternative means of physiologic assessment of lesion severity during coronary angiography.
Adenosine↗
Prevention of nitroglycerin tolerance with diuretics.
Tolerance to prolonged nitroglycerin (NTG) may be due to drug-induced intravascular expansion. To test the hypothesis that concomitant diuretics may reduce volume expansions and thus prevent NTG tolerance, we studied 23 healthy volunteers randomized to hydrochlorthiazide or placebo before and during 74-hour continuous NTG exposure. Venodilator response to NTG was tested serially with venous forearm plethysmography. In the preNTG patch phase venodilator response was similar in both the placebo and diuretic groups. Venodilator capacity was compared after "acute" (2-hour) and "chronic" (74-hour) NTG exposure with NTG patches. Attenuation to NTG was seen in the placebo group, but NTG venodilator activity was fully maintained in the diuretic group. These data suggest that diuretics may be helpful in the prevention of NTG tolerance.
Administration, Oral↗
The role of thrombolytic therapy for acute myocardial infarction.
Thrombolytic therapy is widely available and easily administered and can restore IRA flow. IRA patency restored by thrombolysis salvages ventricular function and reduces mortality rates, albeit with an increased risk of hemorrhagic stroke. The risk of coronary reocclusion after t-PA administration can be reduced with concomitant use of intravenous heparin given in therapeutic doses. It appears that, in terms of mortality reduction and myocardial salvage, the greatest benefit is achieved when early IRA perfusion is normal (TIMI grade 3). Unfortunately, only 50% of patients treated with the most aggressive regimens will achieve normal flow when assessed 90 min after initiating thrombolysis. New strategies using currently available agents given in different dosing regimens, combinations of strategies, and new antithrombotic agents hold the promise of increasing early patency and further reducing both mortality and ventricular dysfunction.
Cerebrovascular Disorders↗
Safety of immediate treadmill testing in selected emergency department patients with chest pain: a preliminary report.
To determine the feasibility and safety of an immediate, symptom-limited, treadmill test on selected emergency department (ED) patients, a convenience sample of 28 patients underwent an exercise treadmill test (ETT) within the first several hours after hospital arrival using the modified Bruce protocol. Patients were included in the study if they presented with otherwise unexplained chest pain consistent with (but not characteristic for) angina pectoris and had a normal electrocardiogram. A negative ETT was seen in 23 of 28 patients, and five of 28 patients had a positive ETT. No patients had serial enzyme or electrocardiogram evolution suggestive of myocardial ischemia, and all patients with a negative ETT were discharged after a full inpatient evaluation designed to rule out unstable coronary disease. At a mean follow-up period of 6.1 months there has been no cardiac morbidity or mortality in the patients with negative ETTs. It was concluded that early ETTS of selected ED patients with chest pain is safe, and an exercise test administered during the ED visit which is negative can preclude unnecessary hospitalization.
Adult↗
Methionine restores the venodilative response to nitroglycerin after the development of tolerance.
Depletion of sulfhydryl groups may contribute to nitroglycerin tolerance after long-term exposure. This study was performed to assess whether methionine, an amino acid capable of augmenting sulfhydryl availability, would restore the venodilative response to sublingual nitroglycerin once tolerance had developed. The venodilative response to organic nitrates was assessed with use of the equilibration technique of forearm plethysmography. Venous volume was measured before and after sublingual administration of 0.4 mg of nitroglycerin at baseline study and after 5 g of intravenous methionine. Retesting was performed 2 h after application of a 10 mg nitroglycerin patch and compared with the response after 74 h of nitroglycerin patch exposure before and after intravenous methionine. Methionine alone had no intrinsic venodilative action. Although the venous volume at rest was unchanged after methionine administration, the response to sublingual nitroglycerin was potentiated compared with baseline values (37 +/- 15% versus 32 +/- 13%, p less than 0.02). During nitroglycerin patch exposure, the response to sublingual nitroglycerin was significantly attenuated at 74 h compared with the response at 2 h of exposure (16 +/- 10% versus 31 +/- 13%, p less than 0.001). The venodilative response to sublingual nitroglycerin was restored at 74 h after methionine administration (35 +/- 14% versus 16 +/- 10%, p less than 0.001). Thus, methionine potentiates the venodilative effect of sublingual nitroglycerin both immediately and in the setting of nitrate tolerance.
Administration, Cutaneous↗
Prevention of nitrate tolerance with angiotension converting enzyme inhibitors.
BACKGROUND: Activation of neurohumoral hormones or sulfhydryl group depletion may contribute to the development of nitroglycerin tolerance. In an attempt to prevent nitrate tolerance, this study evaluated the interaction of nitroglycerin with angiotensin converting enzyme (ACE) inhibitors with and without a sulfhydryl group. METHODS AND RESULTS: Thirty-four subjects were randomized to a 7-day regimen of enalapril 10 mg b.i.d., captopril 25 mg t.i.d., or placebo. Venodilator response to nitroglycerin was assessed with forearm plethysmography by measuring the change in venous volume after administration of 0.4 mg sublingual nitroglycerin. Plethysmographic measurements were obtained serially 1) at baseline, 2) after 4 days of ACE inhibitor or placebo, 3) 2 hours after application of a 10 mg/24 hr nitroglycerin patch, and 4) 74 hours after continuous nitropatch application. ACE inhibition alone caused no significant change in the response to sublingual nitroglycerin. Nitrate response remained unchanged after 2 hours ("acute") of nitropatch exposure in all three groups. After 74 hours ("chronic") of continuous nitropatch application, the venodilator response to sublingual nitroglycerin was reduced by 40% in the placebo group, 10% in the enalapril group, and 2% in the captopril group. This attenuation was significant only in the placebo group (p less than 0.01). Pairwise comparison of nitrate response between groups was significantly different between the captopril and placebo groups (p less than 0.01) and between the placebo and enalapril groups (p less than 0.05). Plasma renin levels increased equally in the enalapril and captopril groups. Body weight increased only in the placebo group, suggesting prevention of nitrate-induced volume expansion in the ACE inhibitor groups. CONCLUSIONS: This study demonstrates that ACE inhibitors may prevent nitrate tolerance to long-term nitrate therapy.
Administration, Cutaneous↗
Patient selection for thrombolytic therapy.
Recent studies have shown that the use of thrombolytic therapy in patients with acute myocardial infarction can reduce mortality 20 to 52%. However, patient selection issues remain to be resolved. These issues include the time window for therapy, treatment based on the site of infarction, treatment based on electrocardiographic criteria and treatment of the elderly population.
Aged↗
Clinical and hemodynamic significance of left ventricular diastolic volume changes by exercise radionuclide ventriculography in coronary artery disease.
Recent studies have suggested that left ventricular (LV) dilatation during exercise radionuclide ventriculography may identify coronary artery disease (CAD). Coronary anatomy and LV end-diastolic pressure at catheterization were compared with results of supine exercise radionuclide ventriculography in 66 patients evaluated for chest pain. Forty-six patients had significant CAD (greater than 75% diameter stenosis) and 20 patients were normal. Radionuclide ventriculography was performed within 18 hours of catheterization, at rest and at peak exercise. Relative LV end-diastolic volumes were extrapolated from end-diastolic counts. LV end-diastolic counts increased during exercise in 19 of 20 normal subjects. In patients with CAD, LV end-diastolic counts increased in 35 (group A) and decreased in 11 (group B). The percent change in LV end-diastolic counts from rest to exercise, rest ejection fraction, exercise ejection fraction and rest LV end-diastolic pressure for each group were 20 +/- 23%, 60 +/- 13%, 67 +/- 13% and 8 +/- 3 mm Hg in normal subjects; 20 +/- 20%, 50 +/- 12%, 47 +/- 13% and 12 +/- 4 mm Hg in group A; and -9 +/- 8%, 54 +/- 21%, 49 +/- 18% and 21 +/- 7 mm Hg in group B (mean +/- standard deviation). An increase in LV end-diastolic counts was unrelated to ejection fraction response or presence of underlying CAD but only correlated to rest LV end-diastolic pressure (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Cardiac Catheterization↗
Potentiation of the hemodynamic effects of acutely administered nitroglycerin by methionine.
It is believed that nitroglycerin causes vasodilatation by interacting with sulfhydryl groups present in vascular smooth muscle. This study was performed to assess whether methionine, an amino acid capable of increasing sulfhydryl availability, would potentiate the hemodynamic effects of nitroglycerin. Nitroglycerin was initially infused in incremental doses from 1 to 50 micrograms/min in all patients to determine the dose required to reduce mean arterial pressure by 10% and pulmonary capillary wedge pressure by 30%. After a washout period, 10 patients received 5 g methionine i.v. and five patients received an equal volume of 5% dextrose in water (control). Nitroglycerin dose titration was then repeated. Methionine alone induced no hemodynamic effects, but after methionine infusion, there was a significant reduction in the nitroglycerin infusion rate required to reach each hemodynamic endpoint (p less than 0.01). In the control group, there was no significant change in responsiveness to nitroglycerin between infusions. Thus, methionine potentiates the hemodynamic effects of acutely administered intravenous nitroglycerin.
Analysis of Variance↗
Acute arrhythmogenicity of doxorubicin administration.
The magnitude of acute arrhythmogenicity of doxorubicin administration has not been characterized. In this study the type and frequency of cardiac arrhythmia is determined in the first hour and first 24 hours following doxorubicin given as a 10-minute infusion. Twenty-nine patients with diverse malignancies were studied with Holter monitors on 33 postdoxorubicin days. Control recordings were made on days remote from doxorubicin treatment. The frequency of arrhythmia that could be attributed to doxorubicin was low: 3% of studies in the first hour postinfusion and 24% of studies in 1 to 24 hours postinfusion. The most commonly seen arrhythmia was an increased frequency of ventricular premature beats. Arrhythmia following doxorubicin infusion is rare in the first hour and more common in the remainder of the first 24 hours postinfusion. There are no acute or long-term adverse consequences related to the appearance of arrhythmia due to doxorubicin.
Adult↗
Recurrent early ischemic events after thrombolysis for acute myocardial infarction.
Myocardium salvaged by early thrombolysis and then perfused through a residual stenosis may be at risk for ischemic events. To investigate this possibility, the short-term (2-week) clinical course of 81 consecutive patients managed within a randomized intracoronary thrombolysis trial was reviewed. All patients underwent coronary angiography within 5 hours of symptoms of acute myocardial infarction and were stratified into the following 3 outcome groups: patients with initially subtotal occlusion (subtotal group, n = 17), those with initial total occlusion and infarct artery reperfusion (reperfused group, n = 24) and those with continued infarct artery occlusion (occluded group, n = 40). Recurrent ischemic events were defined as spontaneous typical angina, provokable angina on predischarge exercise testing, and reinfarction. Eleven of 17 patients (65%) in the subtotal and 11 of 23 patients (48%) in the reperfused groups had an ischemic event (difference not significant). In contrast, 4 of 37 patients (11%) with occlusion had an ischemic event (p less than 0.01 compared with patients in the subtotal or reperfused groups). Four patients were excluded because of early (within 72 hours) elective coronary bypass surgery or death from pump failure. To eliminate the impact of multivessel coronary artery disease (CAD), 39 patients with 1-vessel CAD were analyzed separately. Five of 9 patients (56%) in the subtotal group, 3 of 10 (30%) in the reperfused group and only 2 of 20 (10%) in the occluded group had an ischemic event. These observations suggest the need for a more definitive revascularization strategy for acute myocardial infarction.
Angina Pectoris↗