The risk of family history of ischemic heart disease independent of other well described risk factors has remained difficult to quantitate. Significant coronary artery disease was determined by coronary arteriography to be present in 223 patients and absent in 57 control subjects. Age, sex, blood pressure, serum cholesterol, cigarette smoking and the presence of diabetes and left ventricular hypertrophy on the electrocardiogram were tabulated for each patient and the data used to assign a risk score based on the American Heart Association multivariate model. Subjects were stratified and matched according to risk score to estimate risk of family history independent of familial aggregation of these seven other risk factors. Angina, myocardial infarction, cardiac death and any ischemic heart disease were ascertained in 1,319 first degree relatives. Odds ratios for overall, stratified and matched comparisons of these end points in relatives of patients and control subjects ranged between 2.0 and 3.9 (p less than 0.01 for all comparisons), indicating a higher frequency of all ischemic heart disease end points in relatives of patients with documented coronary artery disease. Life table comparison of patients at lowest risk with those at higher risk showed significantly greater cumulative frequency and earlier age of onset of all ischemic heart disease end points in relatives of low risk patients. These observations indicate that some of the risk associated with family history is independent of familial aggregation of other known risk factors and suggest that the independent effects of family history may be most important in individuals who otherwise are at low risk.
A computerized method for measuring relative coronary arterial stenosis by cinevideodensitometric analysis of 35 mm coronary arteriograms was developed and validated. Video images of projected coronary arteriographic frames were digitized into a 512 x 512 matrix (256 gray levels) by computer analysis that compared integrated contrast density measured over stenotic and normal arterial segments after background subtraction. Pixel density was 70 to 80 pixels/mm2 actual area. In phantom studies performed on plexiglass cylinders, cinevideodensitometric measurements correlated linearly with concentration of contrast medium (r = .99), with cross-sectional areas (r = .99) of contrast-filled cylinders 1 to 4 mm in diameter over a wide range of contrast concentrations (25% to 100%), and with relative stenosis of eccentric lesions in the cylinders (r = .99, SEE -3.9%). In another. Second, an estimation of relative stenosis based on minimal cross-sectional area is a more accurate indicator of blood flow than is that based on the degree of relative narrowing expressed in terms of relative diameters,9-U0 which is the traditional method for interpreting coronary arteriograms subjectively.The fact that there are no techniques for accurately grading the severity of coronary atherosclerotic narrowings from coronary arteriograms is a major limitation in the study of ischemic heart disease. DIAGNOSTIC METHODS-CORONARY ARTERY DISEASEAngiograms recorded on conventional 35 mm arteriographic film can be rapidly digitized by computer processing of the projected angiographic image. The projected image is recorded with a vidicon camera, and the resulting video signal is digitized into a 512 x 512 matrix with 255 gray levels, providing quantification of the optical density of each region of the film. The optical density of each arterial segment recorded on the angiographic frame reflects the volume of contrast medium within the arterial lumen, which directly represents the volume of the arterial segment.In this study a method for measuring the cross-sectional area of coronary stenotic lesions by videodensitometric analysis of 35 mm coronary arteriograms was developed and validated in experiments with phantom models and postmortem human hearts. The hypothesis that videodensitornetric analysis of the optical density of contrast medium within an artery reflects the crosssectional area of the arterial lumen was tested. MethodsRadiographic equipment. Coronary cinearteriograms were recorded on 35 mm cine film (Kodak CFR) at 32 frames/sec with an Arriflex camera. The radiographic equipment consisted of a Philips modular generator, an SRN 10/80 x-ray tube, and a trimodal (6, 10, 14 inch) cesium iodide image intensifier mounted on a Poly Diagnost A arm and scanned with a Plumbicon video tube. The focal spot size for coronary cine fluorography was 0.7 mm. The image intensifier was operated in the 6 inch mode, and x-ray exposure time was 5 msec. Due to the large size of the 14 inch image intensifier, the curvature of the input phosphor va...
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