Samuel H. Brooks

Disease of the left main coronary artery. Surgical treatment and long-term follow up in 267 patients.

Of 4,196 patients undergoing coronary angiography, 297 (7 percent) had left main coronary arterial narrowing. In 188 (4.5 percent) the narrowing was greater than or equal to 70 percent and in 109 (3 percent) it was between 50 and 69 percent. Three patients (1 percent) died at cardiac catheterization. Saphenous vein bypass graft surgery was performed in 267 patients with an operative mortality of 7 percent: in 179 patients the left main coronary narrowing was greater than or equal to 70 percent (operative mortality 9 percent), and in 88 between 50 and 69 percent (mortality rate 2 percent). There was an average of 2.6 grafts per patient. The course of these patients was followed up for 4 3/4 years. At 1 year there was a 92.2 percent survival rate. The rate of survival at 2, 3 and 4 3/4 years, was 91, 89 and 86 percent, respectively. After saphenous vein bypass graft surgery, 75 percent of patients are angina-free and 22.4 percent are in improved condition. Grafts were studied in 51 patients and 85 percent of 128 grafts were found to be patent. It appears that there is improvement in survival and a reduction of symptoms after saphenous vein bypass graft surgery in patients with left main coronary arterial narrowing.

Measurement of atherosclerotic luminal irregularity and obstruction by radiographic densitometry.

This report describes a procedure to quantify stenosis and to detect enface plaques in single plane angiograms. We derived an optical density function proportional to local arterial chord length from arteriographs over a wide range of conditions. Standard radiographs were made of silicone rubber bolus used as the radiopaque medium in cadaver arteries. Replicate arterial casts filled with iodine-bearing contrast medium were radiographed for comparison. Identical atherosclerotic areas in both film sets were scanned with a microdensitometer and vessel chord lengths used to construct arterial cross sections for comparison with vessel casts. Cross-sectional areas derived from cadaver and phantom films were highly correlated with those derived from cast slices (r = 0.997). Thus, luminal cross-sectional areas were accurately estimated independent of plaque location, and accuracy of chord length measurement was +/- 0.28 mm in vessels four to 10 mm in diameter.

Design of human atherosclerosis studies by serial angiography.

Atherosclerosis has been studied by femoral angiography in men with myocardial infarction. Smoking history recorded at entry was the strongest variable asssociated with degree of atherosclerosis at the first angiogram. This correlation was significant at the 1% level in two out of three femoral segments. Fifty-four men had two angiograms; 28 of these men had one additional angiogram. Two variables recorded in the interval between angiograms were significantly correlated with atherosclerosis change in one femoral segment; α-lipoprotein level determined by electrophoresis (a negative correlation, p < 0.01) and maximum systolic blood pressure occurring during an exercise tolerance test (a positive correlation, p < 0.01). An estimate of angiographic atherosclerosis assessment error has been obtained (S.D. = 8.28; in a scale of 1–128) and used to calculate sample size for future clinical trials which employ this endpoint. Testing the effect of therapy on lesion change with angiography requires fewer study subjects observed for a shorter period than is necessary to test a commensurate effect on atherosclerosis-related morbidity or mortality rates. For example, an angiographic study with design features comparable to those of the Coronary Drug Project could require a 1-yr observation period and 132 subjects per test group.

Assessment of Atherosclerosis from Angiographic Images

Summary Raised aortic atheromas can be quantitated by densitometer-computer analysis of edge irregularity on angiographic shadows. Combined measurement of edge irregularity and variation in cross-sectional density provides an angiographic index indicative of local cholesterol concentration in aorta walls and atheromas.

Grading of coronary atherosclerosis Comparison of a modified IAP visual grading method and a new quantitative angiographic technique

Abstract We submit a quantitative method for measuring atherosclerosis from angiograms of autopsied hearts. Casts were made of the coronary vessels of human excised hearts by filling coronary arteries with rapid polymerizing radiopaque silicone rubber. Angiograms of the casts resembled clinical arteriograms. Corresponding segments were marked off on angiograms, and the arterial intimal surface and the arteries graded visually by four graders four times. Vessel edges on the angiograms were located by a film digitizer coupled to a computer. Estimates of atherosclerosis were derived from deviations in the smoothness of the edge. Correlation with pooled visual grades was 0.56, P Computer grading was significantly more reproducible. The standard deviation among graders was 19.5 (coefficient of variation 45 %); between computer runs 0.10 (coefficient of variation 1.17%).

Risk factors and mortality among black, Caucasian, and Latina women with acute myocardial infarction

The purpose of this study was to examine the clinical outcome of acute myocardial infarction among women of three ethnic/racial groups and to determine whether observed differences in outcome are explained by differences in associated risk factors. Nine hundred seventeen (917) consecutive admissions occurred among 810 women, of whom 347 (42.8%) were Caucasian, 258 (31.9%) were black, and 205 (25.3%) were Latina. The overall mortality rate was 13%; the Caucasian rate was significantly higher than the Latina rate (16.9% vs 7%, p < 0.01), as was the black rate (13.8% vs 7%, p < 0.05). Comparing survivors with nonsurvivors among the three groups, hypertension was more common for survivors among blacks, as was a history of angina; in-hospital congestive failure was associated with a higher mortality for blacks and Caucasians, as was in-hospital angina for Caucasians. Univariate and multivariate logistic regression for the outcome variables of congestive failure, in-hospital angina, and mortality, showed race to be a significant factor in the lower mortality rate for Latinas in the univariate analysis. In the multivariate analysis, only in-hospital angina and congestive failure significantly influenced mortality. In this study of myocardial infarction among women of lower socioeconomic status, factors other than race were the primary influences on outcome.

Computerized edge tracking and lesion measurement in coronary angiograms A pilot study comparing smokers with non-smokers

Comparison of coronary atherosclerosis change in a pilot angiographic study of retrospectively matched smokers and controls indicates more rapid progression in smokers. The findings indicate the feasibility of small-scale angiographic trials of treatment designed to ameliorate arterial damage in atherosclerotic smokers who cannot quit.

Discrimination of human arterial pathology by computer processing of angiograms for serial assessment of atherosclerosis change

Abstract Femoral angiograms were made in 21 cadavers under conditions which simulated clinical films. Then these arteries were excised, laid open, and color photographed along side of corresponding casts of the arterial lumen. Twenty-seven segments, 5 cm long, were classified as exemplary of normal vessel, uncomplicated stenosis, or hemorrhagic ulceration. The corresponding angiogram images of these arterial segments were digitized and processed to yield outlines of the vessel edges, and from these, computer measures were developed which described how these outlines deviated from ideal ones. Six of these measures were selected by means of stepwise discriminant analysis to distinguish the type of disease along the 27 exemplary segments, and 96% were correctly classified. Computer processing of angiograms shows promise for discriminating the nature of atherosclerotic lesions.

Computer Assessment of Atherosclerosis from Angiographic Images

A computer method for detection and quantification of atherosclerosis from angiograms has been developed and used to measure lesion change in human clinical trials. The technique involves tracking the vessel edges and measuring individual lesions as well as the overall irregularity of the arterial image. Application of the technique to conventional arterial-injection femoral and coronary angiograms is outlined and an experimental study to extend the technique to analysis of intravenous angiograms of the carotid and cornary arteries is described.

Digital image processing of vascular angiograms

A computer image processing technique has been developed to estimate the degree of athero sclerosis in the human femoral artery. With an angiographic film of the vessel as input, the computer has been programmed to estimate vessel abnormality through a series of measurements, some derived primarily from the vessel edge in formation and others from optical density vari ations within the lumen shadow. These measurements are combined into an atherosclerosis index, which as described below was found in a post-mortem study to correlate well with both visual and chemical estimates of atheroscle rotic disease.