[Quantitative morphology of coronary arteriosclerosis and coronary insufficiency (author's transl)]

International nifedipine trial on anti-atherosclerotic therapy (INTACT)--methodologic implications and results of a coronary angiographic follow-up study using computer-assisted film analysis

Animal experiments demonstrated a significant suppressive effect of various calcium channel blockers on the formation of atherosclerotic lesions. Therefore, a prospective, placebo-controlled, randomized, double blind multicenter study was performed to investigate the inhibitory influence of the calcium channel blocker nifedipine (80 mg/day) on the progression of coronary artery disease in man. Study endpoints were changes of coronary morphology documented by coronary angiography with particular respect to the formation of new coronary stenoses. In 348 out of 425 patients included in the study, coronary angiograms were repeated after three years. The angiograms were standardized by induction of a maximal coronary vasodilation with high doses of nitrates and by using absolutely identical angiographic projections. Quantitative analysis of coronary cineangiograms was performed with the computer-assisted contour detection system CAAS. Parameters were mean and minimal diameter of all segments and minimal stenosis diameter, percent diameter stenosis, length and plaque area of all stenoses. Continuous intake of study medication was registered in 282 patients, 134 on nifedipine and 148 patients on placebo. In these patients, a total of 3808 coronary segments with 893 stenoses (greater than or equal to 20% diameter reduction in at least one angiographic projection) were compared on the baseline and follow-up cineangiograms. The changes in all angiographic parameters analyzed averaged over all patients by considering all angiographic projections analyzed, indicated significant progression of the disease (p less than 0.006). The average changes in all parameters were even about three times more profound, when in the individual patients only the respective projections indicating the maximal changes were considered for the calculation (p less than 0.001). However, with neither of these two analysis modes, the differences in progression between the treatment groups were statistically significant. In the follow-up angiograms, a total of 196 new coronary lesions (185 stenoses, 11 occlusions) were found at previously normal arterial sites. In patients on nifedipine, an average of only 0.58 new lesions per patient were detected versus 0.80 lesions per patient on placebo (-27%; p = 0.031). INTACT is the first prospective angiographic trial on the progression of coronary artery disease using computer-assisted quantitative coronary angiography in such a high number of patients. All parameters analyzed indicated significant progression of coronary artery sclerosis. Nifedipine had no influence on the progression of preexisting coronary stenoses, but inhibited significantly the formation of new angiographically recognizable lesions. Further prospective coronary angiographic trials with calcium channel blockers using a comparably exact method are needed to confirm the results of this study.

Impact of compensatory enlargement of atherosclerotic coronary arteries on angiographic assessment of coronary artery disease

To determine whether compensatory enlargement of atherosclerotic coronary arteries occurs and to what degree it affects the angiographic assessment of coronary artery disease, we performed postmortem coronary angiography of 30 human hearts with suspected coronary artery disease and studied 70 histologic cross sections of the proximal left anterior descending artery and proximal right coronary artery. Angiographic and morphometric analyses of 50 stenoses in proximal and middle sections of the left anterior descending artery, right coronary artery, and left circumflex artery were performed. The control group of 10 human hearts without suspected coronary artery disease was evaluated in the same way. For this purpose, coronary arteries were filled with a methylmethacrylic radiopaque resin at a pressure of 100 mm Hg and closely embedded in a methylmethacrylic resin by use of which shrinkage and mechanical artifacts could be avoided. The area circumscribed by the internal elastic lamina was taken as a measure of the area of the arterial lumen if no plaque had been present. The angiographic and corresponding morphometric degree of stenosis was assessed. A significant correlation (r = 0.85, p less than or equal to 0.0001) was found between the internal elastic lamina area and the area of the plaque (lesion area), suggesting that coronary arteries may enlarge as lesion area increases. With the morphometric degree of stenosis, the expected anatomic diminution of the coronary artery was abolished (r = 0.79, p less than or equal to 0.0001), indicating compensatory enlargement in atherosclerotic segments. Accordingly, the degree of stenosis assessed from in vitro angiograms was underestimated. Compensatory coronary enlargement of the stenotic segment was the main reason for angiographic underestimation. The underestimation factor of up to 3.50 for very mild stenoses decreased to 1.37 at an angiographic degree of 50% area stenosis and 30% diameter stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Postmortem angiographic and pathologic-anatomic findings in coronary heart disease: a comparative study using planimetry

Comparisons of the results of angiographic and pathologic-anatomic estimations of the degree of coronary artery stenosis are rare and the findings contradictory. In the present study, postmortem examinations were carried out on 26 hearts with coronary artery disease. Quantitative planimetric measurements of 203 coronary artery cross-sections were performed and compared with the results of postmortem coronary angiograms. Using a score rating scale, a highly significant difference (P < 0.001) between the angiographic and morphologic findings was detected, with the degree of stenosis and underestimated angiographically in 96 of the 203 sections (47%), overestimated in 18 (9%), and correctly estimated in 89 (44%). The tendency to underestimation was equal in all of the coronary arteries (left anterior descending, circumflex, and right coronary arteries); there were no statistically significant differences (P < 0.20, P < 0.30, P < 0.10). The frequency of angiographic underestimation of the degree of morphologic stenosis--especially in critical stenoses of more than 60%)--has important implications in the assessment of whether coronary artery surgery is warranted.

[Quantitative morphology of coronary arteriosclerosis and coronary insufficiency in heart hypertrophy (author's transl)]

After post-mortem coronary angiography the degree of ventricular hypertrophy was estimated on 18 hearts. The cases were divided in three groups: 9 hearts with right ventricular hypertrophy, 4 hearts with left ventricular hypertrophy and 5 hearts with hypertrophy of both ventricles. Cytophotometric studies revealed a close correlation between absolute weight of heart segments and DNA content of muscle cell nuclei of both ventricles . Radius and area of lumen, thickness and area of both intima and media were measured at serial cross sections of all three coronary arteries. Using these data indices on coronary sclerosis and, including the heart weight, indices on coronary insufficiency were calculated. By determining these indices for the isolated right and left ventricle and the interventricular septum additional criteria suggesting failure of coronary perfusion were obtained. These criteria disclosed that in cases of right ventricular hypertrophy the connective tissue of the right ventricular myocardium was increased only at high values of the insufficiency indices. On the other hand in cases of left ventricular hypertrophy the morphological features of decreased perfusion of the right ventricle were observed at low index values. In all three groups the increased vulnerability of the left ventricle to failure of coronary perfusion was numerically proved.

[Forensic usefulness of coronarometric studies (author's transl)]

Authors examine the forensic usefulness and scope of angiometric studies in cases of sudden death that are presumably caused by coronary heart disease (CHD). Hearts of 35 men aged between 40 and 59 years who died of CHD are studied angiographically, morphologically and microscopically. The control group consists of 34 men of the same range of age who died of unnatural causes. Following to a schematic model with special regard to hemodynamic aspects and the degree of the stenosis a stenosis score is made up for each heart and correlated on a diagram with the corresponding heart weight. It appears that the cases of both groups are different areas but are showing a certain degree of overlap. The variation within both groups is discussed. With regard to the CHD group it is presumed that the factors causing death are too variable as to be defined by the deviced methods exclusively. The causal role of factors other than atherosclerosis in the occurrence of CHD is discussed. Authors conclude that the methods examined could be useful in special forensic problems.

[Comparative enzyme-histochemical studies on normal myocardium, in cases of coronary insufficiency and myocardial infarction (author's transl)]

Comparative histochemical studies with Tetrazolium salt solutions were performed on 25 human and 3 canine hearts. After perfusion of whole hearts with Tetrazolium solutions extensive unstained areas were observed which proved to be artefacts, since they reacted positively after incubation of the heart-slices. The perfusion method of Lichtig, Feldman, Glagov and Wissler (1973) which was proposed for macroscopic and microscopic diagnosis of ischemic cardiac lesions was not found to be suitable for the identification of microcirculatory disturbances. The usual incubation method, however, proved to be useful for the macroscopic localization of recent myocardial infarcts.

[Quantitative morphology of the coronary arteries in the second and third decades of life (author's transl)]

1. In 8 cases in the second decade and 10 cases in the third decade without coronary sclerosis and 5 cases with early sclerosis quantitative measurements were made on graded sections of the coronary arteries which were fixed in toto by compression. The surfaces of the lumen, intima and media were determined planimetrically and the thickness of the intima and media and the radius of the lumen of the three main branches of the coronary arteries were determined micrometrically. A post-mortem coronary angiogram was made of each heart and the connective tissue content of the right and left heart was determined planimetrically. 2. Higher values are found in the absolute measurements of surface and thickness of each cross-section in the third decade than in the second. In both age groups the anterior descending ramus is predominant in all criteria. About the end of the second decade the intima attains the thickness of the media and shows the greatest variability of all parameters, especially in the second decade. In both decades the media plays an equally important role in growth as the intima. In the anterior descending ramus the intima has a higher percentage growth rate than in the right coronary artery and in the left ramus circumflexus. In the third decade it has reached a mean thickness of 122 mu in the initial part of the anterior descending ramus and a mean surface area of 1.18 mm2. In the same area the mean thickness of the media also in the third decade, would be 124 mu, and the mean surface area of the media 1.64 mm2. 3. The indices of coronary sclerosis and coronary insufficiency were determined by the method of Freudenberg, Knieriem, Möller and Janzen (1974). Using the mean values for the second and third decades and calculating the regression in the fourth to seventh decades, we found as upper normal limits a coronary sclerosis index of I = 0.3 for hearts without coronary sclerosis, for the coronary sclerosis index II = 0.6, for the coronary insufficiency index I = 0.3, for the coronary insufficiency index II = 0.6 and for the coronary insufficiency index III = 1.0.