Biomedical subjects
R Chilton
Publications and source records attributed to R Chilton.
The expanding role of HMG-CoA reductase inhibitors (statins) in the prevention and treatment of ischemic heart disease.
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Web alert.
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Can computerization of the exercise test replace the cardiologist?
BACKGROUND: The type of practitioners who use the standard exercise test is changing. Once a tool of the cardiologist, the standard exercise test is now being performed by internists and other noncardiologists. Because this change could be facilitated by computerization similar to the computerized interpretation programs available for the resting electrocardiograph (ECG), we performed this analysis. A secondary aim was to demonstrate the effects of medication status and resting ECG abnormalities on test diagnostic characteristics because these factors affect utility of the exercise test by the generalist. METHODS AND RESULTS: A retrospective analysis was performed of consecutive patients referred at 2 university-affiliated Veteran's Affairs Medical Centers and a Hungarian Hospital for evaluation of chest pain and possible ischemic heart disease. There were 1384 consecutive male patients without a prior myocardial infarction with complete data who had exercise tests and coronary angiography between 1987 and 1997. Measurements included clinical, exercise test data, and visual interpretation of the ECG recordings as well as more than 100 computed measurements from the digitized ECG recordings and compilation of angiographic data from clinical reports. The computer measurements had similar diagnostic power compared with visual interpretation. Computerized measurements from maximal exercise or recovery were equivalent or superior to all other measurements. Prediction equations applied by computer were superior to single ECG measurements. Beta-blockers had no effect on test characteristics, whereas resting ST depression was associated with decreased specificity and increased sensitivity. CONCLUSIONS: Computerized exercise ST measurements are comparable to visual ST measurements by a cardiologist; computerized scores that included clinical and exercise test results exhibited the greatest diagnostic power. Applying scores with a computer allows the practicing physician to improve the diagnostic characteristics of the standard exercise test. This approach is successful even when there is resting ST depression, thus lessening the need for more expensive nuclear or imaging studies.
Predicting severe angiographic coronary artery disease using computerization of clinical and exercise test data.
Currently the standard exercise test is shifting from being a tool for the cardiologist to utilization by the nonspecialist. This change could be facilitated by computerization similar to the interpretation programs available for the resting ECG. Therefore, we sought to determine if computerization of both exercise ECG measurements and prediction equations can substitute for visual analysis performed by cardiologists to predict which patients have severe angiographic coronary artery disease. We performed a retrospective analysis of consecutive patients referred for evaluation of possible or known coronary artery disease who underwent both exercise testing with digital recording of their exercise ECGs and coronary angiography at two university-affiliated Veteran's Affairs medical centers and a Hungarian hospital. There were 2,385 consecutive male patients with complete data who had exercise tests between 1987 and 1997. Measurements included clinical and exercise test data, and visual interpretation of the ECG paper tracings and > 100 computed measurements from the digitized ECG recordings and compilation of angiographic data from clinical reports. The computer measurements had similar diagnostic power compared with visual interpretation. Computerized ECG measurements from maximal exercise or recovery were equivalent or superior to all other measurements. Prediction equations applied by computer were only able to correctly classify two or three more patients out of 100 tested than ECG measurements alone. beta-Blockers had no effect on test characteristics while ST depression on the resting ECG decreased specificity. By setting probability limits using the scores from the equations, the population was divided into high-, intermediate-, and low-probability groups. A strategy using further testing in the intermediate group resulted in 86% sensitivity and 85% specificity for identifying patients with severe coronary disease. We conclude that computerized exercise ST measurements are comparable to visual ST measurements by a cardiologist and computerized scores only minimally improved the discriminatory power of the test. However, using these scores in a stratification algorithm allows the nonspecialist physician to improve the discriminatory characteristics of the standard exercise test even when resting ST depression is present. Computerization permitted accurate identification of patients with severe coronary disease who require referral.
Angioscopic evaluation of site-specific administration of ReoPro.
Systemic administration of newer antiplatelet agents such as the GP IIb/IIIa agent ReoPro (Centocor BV Leiden, The Netherlands) has been shown to decrease the early incidence of recurrent ischemia and recurrent myocardial infarction. The currently approved protocol for administration of ReoPro involves an initial weight adjusted bolus followed by a systemic infusion over the next 12 hr. The systemic administration is proposed as the only route of administration because it is stated that the drug must be exposed to circulating platelets. An alternative approach would be to deliver ReoPro locally and allow the platelets to disaggregate only when in contact with the local arterial wall. The optimal method of monitoring the efficacy of such a strategy is to visually assess the presence of platelet rich or red blood cell rich thrombus using angioscopy. We report our initial experience in 12 patients who received local administration of ReoPro using currently approved catheters for local administration of agents into coronary arteries who were evaluated before and after intervention using intracoronary angioscopy. None of the patients received a subsequent 12-hr infusion. There was successful resolution of thrombus in 11 of 12 patients. Recurrent ischemia occurred in one patient without myocardial infarction.
Fluvastatin versus pravastatin.
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Twenty-three years of addict reporting: a reanalysis of police supplied drug use data.
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